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A model of neuropathic pain induced by sorafenib in the rat: Effect of dimiracetam
NeuroToxicology 50 (2015) 101–107
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NeuroToxicology
Full Length Article
A model of neuropathic pain induced by sorafenib in the rat: Effect of dimiracetam Lorenzo Di Cesare Mannelli a,*, Mario Maresca a, Carlo Farina b,c, Michael W. Scherz c, Carla Ghelardini a a
Department of Neuroscience, Psychology, Drug Research and Child Health, - Neurofarba - Pharmacology and Toxicology Section, University of Florence, Viale G. Pieraccini, 6, 50139 Firenze, Italy Neurotune AG, Wagistrasse 27a, CH-8952 Schlieren, Switzerland c Metys Pharmaceuticals, Friedrichstrasse 6, CH-4055 Basel, Switzerland b
A R T I C L E I N F O
A B S T R A C T
Article history: Received 25 May 2015 Received in revised form 28 July 2015 Accepted 3 August 2015 Available online 5 August 2015
Background: Sorafenib is a kinase inhibitor anticancer drug whose repeated administration causes the onset of a peripheral painful neuropathy. Notably, the efficacy of common analgesic drugs is not adequate and this often leads pre-mature discontinuation of anticancer therapy. The aim of this study was to establish a rat model of sorafenib-induced neuropathic pain, and to assess the effect of the new anti-neuropathic compound dimiracetam in comparison with gabapentin, pregabalin and duloxetine. Methods: Male Sprague-Dawley rats were treated i.v. (10 mg kg 1), i.p. (10 and 30 mg kg 1) or p.o. (80 and 160 mg kg 1) with sorafenib once daily for 21 days. Pain behaviour measurements (cold plate, paw pressure, electronic von Frey) were performed on days 0, 7, 14 and 21. Results: Sorafenib lowered the paw-licking threshold to non-noxious cold stimuli on day 14 of all protocols evaluated. The i.p. administration resulted in greater efficacy than the other administration routes. Sorafenib treatments did not affect paw-withdrawal responses to non-noxious or to noxious mechanical stimuli. On day 14, dimiracetam (300 mg kg 1), gabapentin (100 mg kg 1), pregabalin (30 mg kg 1) and duloxetine (30 mg kg 1) were acutely administered p.o. in sorafenib i.p.-treated rats. A single oral dose of dimiracetam induced a statistically significant increase of the pain threshold 15 min after administration. Pregabalin induced a comparable effect, whereas gabapentin and duloxetine were ineffective. Repeated twice-daily administration of dimiracetam (150 mg kg 1 p.o.), starting on the first day of i.p sorafenib administration, significantly protected rats from sorafenib-induced decrease in the paw-licking threshold. Conclusions: A rat model of sorafenib-induced hypersensitivity to cold stimulation has been established. Dimiracetam and pregabalin are effective in prevention of sorafenib-induced neuropathy in this model. ß 2015 Elsevier Inc. All rights reserved.
Keywords: Chemotherapy-induced neuropathy Neuropathic pain Sorafenib Dimiracetam Pregabalin Pain model
1. Background Neuropathic symptoms are commonly observed in patients receiving antitumor chemotherapy, often preventing completion of the chemotherapeutic cycle (Kennedy, 2007). Chemotherapyinduced neuropathy consists mainly of sensory symptoms, rather than of motor symptoms (Cavaletti et al., 2013), and includes mechanical and cold allodynia, ongoing burning pain, tingling, and allodynic sensation in hands and feet, as well as a chronic foot/leg,
* Corresponding author. Tel.: +39 0552758395; fax: +39 0552758181. E-mail address: lorenzo.mannelli@unifi.it (L. Di Cesare Mannelli). http://dx.doi.org/10.1016/j.neuro.2015.08.002 0161-813X/ß 2015 Elsevier Inc. All rights reserved.
hand/arm numbness (Cersosimo, 2005). Platinum analogues, taxanes, vinka alkaloids, epothilones and proteosoma inhibitors have been reported to be the most predominant anticancer drug families causing peripheral neuropathy even if with different neurotoxic profiles and with several clinical manifestations (Chu et al., 2015). Besides them, sorafenib, a non-selective multikinase-inhibitor (MKI) approved for the treatment of renal cell carcinoma (RCC), hepatocellular carcinoma (HCC) and metastatic differentiated thyroid carcinoma (DTC) (Escudier et al., 2007; Llovet et al., 2008; Blair and Plosker, 2015), generates the handfoot syndrome (HFS), characterized by ulcerative dermatitis and pain on hands and feet after 3 weeks of treatment (Awada et al., 2005; Cicek et al., 2009).
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It is important to note that there is currently no effective treatment to prevent or reverse the painful condition associated to chemotherapy-induced neuropathy (Hershman et al., 2014). The unequivocal treatment of pain induced by anticancer drugs is made difficult by the several, unclear mechanisms underlying chemotherapy-induced neurotoxicity. Accordingly, the management of the sorafenib-dependent painful neuropathy occurring in HFS lacks effective treatment strategies (Walko and Grande, 2014) and, to date, the mechanisms of this adverse effect have not yet been elucidated. The management of pain in HFS is limited to topical or systemic treatments (nonsteroidal anti-inflammatory drugs, codeine and pregabalin), unable to completely control the symptom and to avoid dose modification or discontinuation of the anticancer therapy (Lacouture et al., 2008). The development of effective therapeutic strategies for the control of sorafenib-induced neuropathy is limited by both the lack of knowledge about its mechanism of neurotoxicity, and the absence of an animal model for preclinical research. The aim of the present study was to develop a rat model of sorafenib-induced neuropathic pain by evaluating the effect of different dosages and routes of administration on the pain threshold alteration evoked by mechanical and thermal noxious and non-noxious stimuli. Moreover, the efficacy of compounds usually recommended for the management of chemotherapyinduced neuropathy was evaluated. 2. Methods 2.1. Animals Male Sprague-Dawley rats (Harlan, Varese, Italy) weighing approximately 200 to 250 g at the beginning of the experimental procedure were used. Animals were housed in CeSAL (Centro Stabulazione Animali da Laboratorio, University of Florence) and used at least 1 week after their arrival. Four rats were housed per cage (size 26–41 cm); animals were fed with standard laboratory diet and tap water ad libitum, and kept at 23 1 8C with a 12 h light/dark cycle, light at 7 a.m. All animal manipulations were carried out according to the European Community guidelines for animal care (DL 116/92, application of the European Communities Council Directive of 24 November 1986 (86/609/EEC). The ethical policy of the University of Florence complies with the Guide for the Care and Use of Laboratory Animals of the US National Institutes of Health (NIH Publication No. 85-23, revised 1996; University of Florence assurance number: A5278-01). Formal approval to conduct the experiments described was obtained from the Italian Ministry of Health (N854/ 2014-B) and from the Animal Subjects Review Board of the University of Florence. Experiments involving animals have been reported according to ARRIVE guidelines (Kilkenny et al., 2010). 2.2. Drug administration Sorafenib (APIChem Technology Co., Ltd, Hangzhou, China) was dissolved in a vehicle constituted by 1% ethanol, 1% Cremophor, 98% saline for the intraperitoneal (i.p.) and intravenously (i.v.; in the tail vein) injections and in carboxymethylcellulose for the per os (p.o.) treatment. Gabapentin, pregabalin, duloxetine (SigmaAldrich, Milan, Italy) and dimiracetam (Neurotune AG, Schlieren, Switzerland) were dissolved in water. Control rats were treated with an equal volume of vehicles. Sorafenib was administered i.p. and p.o once daily for 21 days and i.v. for 14 days. Gabapentin (100 mg kg 1), pregabalin (30 mg kg 1), duloxetine (30 mg kg 1) and dimiracetam (300 mg kg 1) were injected once on day 14 of the sorafenib treatment (i.p.) to evaluate their acute effect. In the preventive protocol dimiracetam (150 mg kg 1) and pregabalin (15 mg kg 1) were given twice daily (in the morning and in the
evening) p.o. for 14 days starting from first day in which sorafenib was injected. In the preventive protocol 10 mg kg 1 sorafenib was injected daily i.p. for 14 days. 2.3. Paw pressure test The nociceptive threshold in the rat was determined by an analgesimeter (Ugo Basile, Varese, Italy), according to the method described by (Leighton et al., 1988). Briefly, a constantly increasing pressure was applied to a small area of the dorsal surface of the hind paw using a blunt conical probe by a mechanical device. Mechanical pressure was increased until vocalization or a withdrawal reflex occurred while rats were lightly restrained. Vocalization or withdrawal reflex thresholds were expressed in grams (g). Rats scoring below 40 g or over 75 g during the test before drug administration were rejected (25% of all rats). Mechanical pressure application was stopped at 120 g. 2.4. Von Frey test The animals were placed in 20 cm 20 cm plexiglas boxes equipped with a metallic mesh floor, 20 cm above the bench. A habituation of 15 min was allowed before the test. An electronic Von Frey hair unit (Ugo Basile, Varese, Italy) was used: the withdrawal threshold was evaluated by applying force ranging from 0 to 50 grams with a 0.2 gram accuracy. Punctuate stimulus was delivered to the mid-plantar area of each anterior paw from below the mesh floor through a plastic tip and the withdrawal threshold was automatically displayed on the screen. Paw sensitivity threshold was defined as the minimum pressure required to elicit a robust and immediate withdrawal reflex of the paw. Voluntary movements associated with locomotion were not taken as a withdrawal response. Stimuli were applied on each anterior paw with an interval of 5 s. The measure was repeated 5 times and the final value was obtained by averaging the 5 measures (Sakurai et al., 2009). 2.5. Cold plate test The animals were placed in a stainless box (12 cm 20 cm 10 cm) with a cold plate as floor. The temperature of the cold plate was kept constant at 4 8C 1 8C. Pain-related behaviours (i.e. lifting and licking of the hind paw) were observed and the time (s) of the first sign was recorded. The cut-off time of the latency of paw lifting or licking was set at 60 s. 2.6. Statistical analysis Behavioral measurements were performed on 10 rats for each treatment carried out in 2 different experimental sets. Results were expressed as means s.e.m. and the analysis of variance was performed by one way ANOVA. A Bonferroni’s significant difference procedure was used as post-hoc comparison. P values of less than 0.05 or 0.01 were considered significant. Data were analyzed using the ‘‘Origin 9’’ software (OriginLab, Northampton, USA). 3. Results Sorafenib was i.v. infused (10 mg kg 1) daily for 14 days, while the i.p. (10 or 30 mg kg 1) and p.o. (80 or 160 mg kg 1) administrations were repeated daily for 21 days. Behavioural measurements were performed on days 0, 7, 14 and 21. In Figure 1, the response to a cold non-noxious stimulus (Cold plate test) is shown. Sorafenib i.v. (10 mg kg 1) significantly lowered rats’ licking latency on day 14 (20.5 2.5 s vs 28.4 2.0 s of vehicletreated group) (Figure 1a). The i.p. injection of 10 and 30 mg kg-1 of
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Fig. 1. Thermal non-noxious stimulus, Cold plate test. The response to a thermal stimulus was evaluated by cold plate test measuring the latency (seconds) to painrelated behaviors (lifting or licking of the paw). Rats were intravenously, intraperitoneally or orally treated once daily with sorafenib (10, 30, 80 and 160 mg kg 1). Behavioural test was performed on day 0, 7, 14 and 21 (only for i.p. and p.o. administrations). Control animals were treated with vehicles. Each value represents the mean of 10 rats per group, performed in 2 different experimental sets. *P < 0.01 versus vehicle treated rats.
sorafenib significantly reduced the time response to a cold stimulus on day 14 (12.1 2.1 s and 12.2 0.8 s, respectively, vs 28.4 2.0 s of vehicle) and on day 21 (12.0 3.6 s and 11.3 0.6 s, respectively, vs 29.0 0.7 s of vehicle) (Figure 1b). Moreover, the p.o. administration of sorafenib reduced the pain threshold on day 21, as shown in Figure 1c. The effects induced by 80 or 160 mg kg-1 of sorafenib i.p. were comparable: 20.0 3.4 s and 18.0 1.8 s, respectively, vs 29.0 0.7 s of vehicle-treated rats. The response to a mechanical non-noxious stimulus was evaluated by the Von Frey test (Fig. 2). Sorafenib i.v. did not significantly alter the withdrawal threshold after 7 and 14 days of treatment (Fig. 2a). The i.p.-treated group (30 mg kg 1) showed a decreased threshold on days 14 and 21 (24.7 3.4 g and
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Fig. 2. Mechanical non-noxious stimulus, Von Frey test. The withdrawal threshold was evaluated by Von Frey apparatus as a response evoked by a mechanical stimulus. Rats were intravenously, intraperitoneally or orally treated with sorafenib (10, 30, 80 or 160 mg kg 1) and behavioural measurements were assessed on day 0, 7, 14 and 21 (only for i.p. and p.o. administrations). Control animals were treated with vehicles or saline. Each value represents the mean of 10 rats per group, performed in 2 different experimental sets.
25.7 2.1 g, respectively, vs 31.9 2.0 g of vehicle) without reaching statistical significance (Fig. 2b). The p.o. treatment did not modify the response evoked by a mechanical non-noxious stimulus (Fig. 2c). Fig. 3 shows the animal sensitivity to a mechanical noxious stimulus measured by the Paw pressure test. The repeated administration of sorafenib (i.v., i.p. or p.o.) did not evoke significant hypersensitivity. Focusing on the i.p. administration protocol and on the measurements performed by cold non-noxious stimuli, the responsiveness of sorafenib-induced pain to a common pain reliever was evaluated. On day 14 of sorafenib i.p. administration, 100 mg kg 1 gabapentin, 30 mg kg 1 pregabalin, 30 mg kg 1 duloxetine and 300 mg kg 1 dimiracetam were acutely administered p.o. and the pain threshold was evaluated over time (Cold
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Fig. 4. Thermal non-noxious stimulus, Cold plate test. The response to a thermal stimulus was evaluated by cold plate test measuring the latency (seconds) to painrelated behaviours (lifting or licking of the paw). Rats were daily intraperitoneally treated with sorafenib 10 mg kg 1 and behaviour was measured on day 14. Gabapentin 100 mg kg 1, pregabalin 30 mg kg 1, duloxetine 30 mg kg 1 were p.o. administered and measurements were assessed 15, 30, 45 and 60 min after injection. Control rats were treated with vehicle. Each value represents the mean of 10 rats per group, performed in 2 different experimental sets. ^P < 0.05 versus sorafenib + vehicle treated rats.
Fig. 3. Mechanical noxious stimulus, Paw pressure test. Rats were intravenously, intraperitoneally or orally treated once daily with sorafenib (10, 30, 80 and 160 mg kg 1), and the sensibility to a mechanical stimulus was measured by Paw pressure test on day 0, 7, 14 and 21 (only for i.p. and p.o. administrations). Control animals were treated with vehicles or saline. Each value represents the mean of 10 rats per group, performed in 2 different experimental sets.
plate test). As depicted in Fig. 4, a single oral dose of dimiracetam significantly increased the licking latency 15 min after injection (19.8 1.5 s). The efficacy was comparable to that induced by pregabalin (19.0 1.7 s). Gabapentin and duloxetine were ineffective. To assess the preventive effect of repeated doses of dimiracetam, a subchronic treatment protocol was performed. Dimiracetam was administered twice daily at the dose of 150 mg kg 1 p.o. from the first day in which sorafenib (10 mg kg 1 i.p. daily) was injected. Pregabalin (15 mg kg 1 p.o. twice daily) was used as reference compound. On day 14, the pain threshold was evaluated by the Cold plate test at time 0, before dimiracetam or gabapentin morning administration (Fig. 5). Dimiracetam-treated animals showed a licking latency significantly higher (sorafenib + dimiracetam; 24.3 0.8 s) than sorafenib + vehicle-treated rats (14.8 1.3 s). The effect of dimiracetam was unmodified by a new administration
Fig. 5. Effect of dimiracetam-repeated treatment, Cold plate test. Rats were daily intraperitoneally treated with sorafenib 10 mg kg 1 and dimiracetam (150 mg kg 1 p.o. twice daily), in comparison to pregabalin (15 mg kg 1 p.o. twice daily) or vehicle. On day 14, the response to a thermal stimulus was evaluated by cold plate test measuring the latency (seconds) to pain-related behaviours (lifting or licking of the paw). Measurements were performed before dimiracetam or pregabalin treatments (time 0) and over time after the morning treatment. Control rats were treated with vehicle. Each value represents the mean of 10 rats per group, performed in 2 different experimental sets. ^P < 0.05 and ^^P < 0.01 versus sorafenib + vehicle treated rats.
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and it was still significant 48 h after treatment. The effect of pregabalin was lower (20.9 0.9 s) and shorter lasting (24 h). 4. Discussion The present results describe a model of sorafenib-induced neuropathic pain in the rat. Repeated treatment with sorafenib by different routes of administration (i.v., i.p. and p.o.) induces hypersensitivity to thermal (cold) non-noxious, but not to mechanical noxious or non-noxious stimuli. The oral dose usually employed in clinic (400 mg twice daily; Walko and Grande, 2014) is comparable to the lower dose in the rat (80 mg kg 1) studied here, as calculated by the body surface area (BSA) normalization method (Reagan-Shaw et al., 2008). The high dose (160 mg kg 1) has a similar neuropathic effect. The i.v. and i.p. administrations of sorafenib also exert a strong decrease of pain threshold in response to a cold stimulus. Notably, sorafenib i.p. (10 and 30 mg kg 1) causes a greater hypersensitivity in comparison to the oral treatments of 80 mg kg 1 or 160 mg kg 1. Although no significant alteration in response to a mechanical noxious or non-noxious stimulus are evident, 10 mg kg 1 sorafenib i.v. and 30 mg kg 1 i.p. show a tendency to lower the paw withdrawal threshold in response to a mechanical non-noxious stimulus. Sorafenib is a non-selective multi-kinase-inhibitor approved for the treatment of renal cell carcinoma (RCC), hepatocellular cell carcinoma (HCC) and metastatic differentiated thyroid carcinoma (DTC) by the US Food and Drug Administration (Escudier et al., 2007; Llovet et al., 2008; Blair and Plosker, 2015). The efficacy of sorafenib has also been demonstrated, alone or in association, in clinical phase I/II study and in patients with metastatic breast cancer (Baselga et al., 2012). Several clinical studies highlighted the onset of a variety of side effects, during the treatment with sorafenib and other MKIs such as Sunitinib (Lacouture et al., 2008; Smolle et al., 2014). Among them, the development of painful neuropathic syndrome has been frequently reported (Awada et al., 2005; Abou-Alfa et al., 2006). In particular, Lo Conte and colleagues described HFS, also called palmar-plantar erythrodysesthesia (PPE) as the most limiting adverse effect recurring in 30% of patients treated with sorafenib 400 mg b.i.d. p.o. (Lo Conte et al., 2013). Tingling, numbness and tightness on hands and feet are the earliest symptoms representing the 1st grade of toxicity. Within few days the syndrome evolves in dysesthesia and severe pain, the main clinical manifestations of the 2nd and 3rd grades of HFS, forcing patients to interrupt chemotherapy (Lacouture et al., 2008; Walko and Grande, 2014). Clinical data suggest that a small-fiber neuropathy could be the cause of pain and dysesthesia in HFS (Stubblefield et al., 2006). The preferential damage to the small diameter, myelinated and unmyelinated fibers could directly alter the afferent thermal (hot and cold) and nociceptive transmission (Al-Shekhlee et al., 2002). Our data suggest sorafenib may specifically interfere with the nociceptive C-fibers, normally involved in thermal stimuli transmission (Shir and Seltzer, 1990), as we observe the development of thermal but not mechanical hypersensitivity in the rat. In particular, we evaluated the response to cold non noxious stimuli since cold allodynia has been associated to several types of neuropathy induced by anticancer drug (Sisignano et al., 2014). On the contrary, hypersensitivity to heat is common in animal models of traumatic nerve injury pain but it is very minor or absent in rat models of chemotherapy-induced as well as in patients suggesting that the pathophysiological mechanisms responsible for neuropathic pain are at least partly different depending on the cause of the nerve damage (Bennett, 2010). Moreover, some author suggests the loss of heat sensitivity as a hallmark symptom due to preferential damage to myelinated primary afferent sensory nerve fibers in the presence or absence of
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demyelination in chemotherapy-induced neuropathy (Han and Smith, 2013). Sorafenib seems to evoke electively a cold hypersensitivity even if the mechanism by which sorafenib affects fiber transmission and, in turn, evokes the onset of painful neuropathy is not well established. Sorafenib was initially designed as a potent inhibitor of Raf serine/threonine kinase isoforms. Nevertheless, its anti-angiogenesis and anti-proliferative effects are primarily due to the blockade of VEGF receptors (VEGFR-1, VEGFR-2 and VEGFR-3) and PDGF receptors (PDGFR-b, in particular), considered the initiators of the signaling pathway of tumor vessel formation. The inhibition of cKIT and Flt3, two receptor tyrosine kinases, contributes to the sorafenib anti-angiogenesis properties (Erber et al., 2004; Wilhelm et al., 2004; Wilhelm et al., 2008) as well as the inhibitory properties against the soluble epoxide hydrolase may participate in sorafenib efficacy (Liu et al., 2009). Since the inhibition of PDGFR or VEGFR alone does not result in HFS provoked by MKIs, both VEGFRs and PDGFRs blockade seems to be essential for the neurotoxicity (Thompson et al., 2006). VEGF has several functions in neural cells independent from its role in vessels. It promotes neurogenesis, neuronal migration and survival, axon guidance and synaptic plasticity (Mackenzie and Ruhrberg, 2012). Furthermore, VEGF exerts neuroprotective effects in diabetic- and paclitaxelinduced sensory neuropathy via the up regulation of BCL2 protein (Verheyen et al., 2013). On the other hand, the inhibition of VEGFR pathway as well as the reduction of VEGF levels may cause neuronal damage, affecting BCL2 protein expression (Verheyen et al., 2013). PDGFRs are generally expressed on the surface of pericytes, one of the main cell components of the blood brain barrier (BBB) together with astrocytes and endothelial cells so forming the neurovascular unit (Winkler et al., 2010). PDGFR stimulation regulates pericyte recruitment and enhances their proliferation (Winkler et al., 2011) contributing to the BBB homeostasis maintenance. On the other hand, PDGFR inhibition promotes pericyte degeneration, which, in turn, may be the cause of the BBB disruption and the starting point of neuroinflammatory and neurodegenerative processes (Dalkara et al., 2011). Moreover, also c-KIT and Flt-3 receptor are involved in neurotrophic and neuroprotective signals (Dhandapani et al., 2005) even if the effect of their inhibition in pain sensitivity has not yet been investigated. The lack of knowledge about the mechanisms of sorafenib neurotoxicity involves a poverty of therapeutic options. Currently, the prophylactic approach is aimed to prevent dermatological symptoms. For the 1st grade of toxicity, urea or salicylic acid creams or 0.05% clobetasol are prescribed for the treatment of dermatological symptoms. Later, according to the onset of painful signs, topic 2% lidocaine is suggested. Progressively, when painful symptoms become more intense, systemic pain relievers (NSAIDs, codeine or pregabalin) are recommended. However, for the high grades of toxicity a dose reduction of sorafenib by about 50% for a 7 to 28 day period should be considered. The discontinuation of therapy may be suggested until regression to the 1st grade of toxicity (Lacouture et al., 2008). The inadequacy of care for neuropathic sensory symptoms caused by the use of sorafenib (Walko and Grande, 2014), fits into the complicated context of the prevention and treatment of neuropathies induced by chemotherapy agents. To date, compounds used for the treatment of other neuropathies such as diabetic neuropathy and post-herpetic neuropathy, are commonly employed also in the management of chemotherapy-induced neuropathies even though their different etiopathology. As reported by Hershman et al. (2014), no agents are recommended for the prevention of chemotherapy-induced neuropathies since the paucity of high-quality, consistent evidence. Duloxetine has been reported to decrease pain, numbness and tingling in oxaliplatin – but not in paclitaxel-treated patients (Smith et al.,
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2013), two small trials failed to demonstrate the efficacy of tricyclic antidepressant in decreasing painful symptoms during taxanes, platinum or Vinca alkaloid treatments (Hammack et al., 2002; Kautio et al., 2008). Furthermore, the use of gabapentin has been demonstrated inconclusive in chemotherapy-induced neuropathy (Rao et al., 2007; Rao et al., 2008), but given the limited other treatment options and the utility of this molecule (or that of related drugs like pregabalin) in other neuropathic pain conditions encourages its clinical use (Hershman et al., 2014). To the best of our knowledge no clinical data are available about the treatment of sorafenib neurotoxicity. In the preclinical model of sorafenib-induced neuropathic pain developed in the present research gabapentin and duloxetine are ineffective. Interestingly, the racetam derivative dimiracetam shows an efficacy comparable to that induced by pregabalin. A single administration of dimiracetam counteracts established pain induced by sorafenib. Moreover, the association dimiracetamsorafenib in a repeated-treatment protocol significantly reduced hypersensitivity showing a longer lasting effect than pregabalin. Racetams, also called nootropics, are a family of 2-pyrrolidinone derivatives originally profiled as cognition enhancers. A report of efficacy of nefiracetam against tactile and thermal hyperalgesia in mice (Rashid and Ueda, 2002) suggested that chemical modifications of the racetam structure might confer powerful antineuropathic pain activity. Dimiracetam was active on trauma-dependent neuropathic pain induced by chronic constriction injury of the sciatic nerve and on diabetic neuropathy retaining at the same time its outstanding efficacy of improving cognition in animal models (Farina et al., 2008). Recently we have reported that dimiracetam, acutely or repeatedly administered, is very effective in models of chemotherapy-induced neuropathic pain induced by the anticancer agent oxaliplatin or by antiretroviral drugs with an excellent tolerability profile (Fariello et al., 2014). Dimiracetam shares with pregabalin an effect on the glutamatergic system since pregabalin reduces the release of synaptic vesicles from glutamatergic terminals (Micheva et al., 2006) and dimiracetam counteracts the NMDA-induced release of glutamate in synaptosomal preparations from rat spinal cord (Fariello et al., 2014). This evidence suggests the central nervous system as a relevant site for the dimiracetam’s mechanism of action. Dimiracetam is currently in clinical development for treatment and/or prevention of chemotherapy-induced peripheral neuropathy. 5. Conclusions Sorafenib repeated administrations in the rat induce the onset of sensitive neuropathy characterized by hypersensitivity to thermal (cold) stimuli. The pain relieving efficacy of dimiracetam is shown, suggesting this compound may be a promising treatment for sorafenib-induced neuropathic pain. Conflict of interests MS and CF are employees of Metys Pharmaceuticals. CG performed the work in the framework of a research contract with Neurotune AG. This study was performed without any financial or other contractual agreements that may cause conflict of interest. The other authors declare no conflict of interests. Author’s contribution LDCM and MM performed the experimental tests; LDCM, CG and CF performed the statistical analysis of data; LDCM, CG, CF and MS participated in the design of the study; LDCM, MM, CG, CF and MS conceived of the study, and participated in its coordination
and helped to draft the manuscript. All authors read and approved the final manuscript. Acknowledgements This research was funded by the Italian Ministry of Instruction, University and Research (MIUR), University of Florence and Neurotune AG. References Abou-Alfa, G.K., Schwartz, L., Ricci, S., Amadori, D., Santoro, A., Figer, A., Phase, I.I., 2006. study of sorafenib in patients with advanced hepatocellular carcinoma. J. Clin. Oncol. 24, 4293–4300. Al-Shekhlee, A., Chelimsky, T.C., Preston, D.C., 2002. Review: small-fiber neuropathy. Neurologist 8, 237–253. Awada, A., Hendlisz, A., Gil, T., Bartholomeus, S., Mano, M., de Valeriola, D., et al., 2005. Phase I safety and pharmacokinetics of BAY 43-9006 administered for 21 days on/7 days off in patients with advanced, refractory solid tumours. Br. J. Cancer 92, 1855–1861. Baselga, J., Segalla, J.G., Roche´ , H., Del Giglio, A., Pinczowski, H., Ciruelos, E.M., 2012. Sorafenib in combination with capecitabine: an oral regimen for patients with HER2-negative locally advanced or metastatic breast cancer. J. Clin. Oncol. 30, 1484–1491. Bennett, G.J., 2010. Pathophysiology and animal models of cancer-related painful peripheral neuropathy. Oncologist 15 (Suppl. 2), 9–12. Blair, H.A., Plosker, G.L., 2015. Sorafenib: a review of its use in patients with radioactive iodine-refractory, metastatic differentiatedthyroid carcinoma. Target Oncol. 10, 171–178. Cavaletti, G., Cornblath, D.R., Merkies, I.S., Postma, T.J., Rossi, E., Frigeni, B., et al., 2013. The chemotherapy-induced peripheral neuropathy outcome measures standardization study: from consensus to the first validity and reliability findings. Ann. Oncol. 24, 454–462. Cersosimo, R.J., 2005. Oxaliplatin-associated neuropathy: a review. Ann. Pharmacother. 39, 128–135. Chu, S.H., Lee, Y.J., Lee, E.S., Geng, Y., Wang, X.S., Cleeland, C.S., 2015. Current use of drugs affecting the central nervous system for chemotherapy-induced peripheral neuropathy in cancer patients: a systematic review. Support Care Cancer 23, 513–524. Cicek, D., Kandi, B., Dagli, F.A., Karaoglu, A., Haligur, B.D., 2009. Pre-treatment global quality of health predicts progression free survival in metastatic kidney cancer patients treated with sorafenib or sunitinib. J. Can. Res. Clin. Oncol. 135, 61–67. Dalkara, T., Gursoy-Ozdemir, Y., Yemisci, M., 2011. Brain microvascular pericytes in health and disease. Acta Neuropathol. 122, 1–9. Dhandapani, K.M., Wade, F.M., Wakade, C., Mahesh, V.B., Brann, D.W., 2005. Neuroprotection by stem cell factor in rat cortical neurons involves AKT and NFkappaB. J. Neurochem. 95, 9–19. Erber, R., Thurnher, A., Katsen, A.D., Groth, G., Kerger, H., Hammes, H.P., et al., 2004. Combined inhibition of VEGF and PDGF signaling enforces tumor vessel regression by interfering with pericyte-mediated endothelial cell survival mechanisms. FASEB J. 18, 338–340. Escudier, B., Eisen, T., Stadler, W.M., Szczylik, C., Oudard, S., Siebels, M., et al., 2007. Sorafenib in advanced clear-cell renal-cell carcinoma. N. Engl. J. Med. 356, 125–134. Fariello, R.G., Ghelardini, C., Di Cesare Mannelli, L., Bonanno, G., Pittaluga, A., Milanese, M., et al., 2014. Broad spectrum and prolonged efficacy of dimiracetam in models of neuropathic pain. Neuropharmacology 81, 85–94. Farina, C., Gagliardi, S., Ghelardini, C., Martinelli, M., Norcini, M., Parini, C., Petrillo, P., Ronzoni, S., 2008. Synthesis and biological evaluation of novel dimiracetam derivatives useful for the treatment of neuropathic pain. Bioorg. Med. Chem. 16, 3224–3232. Hammack, J.E., Michalak, J.C., Loprinzi, C.L., Sloan, J.A., Novotny, P.J., Soori, G.S., et al., 2002. Phase III evaluation of nortriptyline for alleviation of symptoms of cis-platinum-inducedperipheral neuropathy. Pain 98, 195–203. Han, Y., Smith, M.T., 2013. Pathobiology of cancer chemotherapy-induced peripheral neuropathy (CIPN). Front. Pharmacol. 4, 156, http://dx.doi.org/ 10.3389/fphar.2013.00156. Hershman, D.L., Lacchetti, C., Dworkin, R.H., Lavoie Smith, E.M., Bleeker, J., Cavaletti, G., et al., 2014. Prevention and management of chemotherapyinduced peripheral neuropathy in survivors of adult cancers: American Society of Clinical Oncology clinical practice guideline. J. Clin. Oncol. 32, 1941–1967. Kautio, A.L., Haanpa¨a¨, M., Saarto, T., Kalso, E., 2008. Amitriptyline in the treatment of chemotherapy-induced neuropathic symptoms. J. Pain Symptom Manage. 35, 31–39. Kennedy, J.D., 2007. Neuropathic pain: molecular complexity underlies continuing unmet medical need. J. Med. Chem. 50, 2547–2556. Kilkenny, C., Browne, W.J., Cuthill, I.C., Emerson, M., Altman, D.G., 2010. Improving bioscience research reporting: The ARRIVE guidelines for reporting animal research. J. Pharmacol. Pharmacother. 1, 94–99. Lacouture, M.E., Wu, S., Robert, C., Atkins, M.B., Kong, H.H., Guitart, J., et al., 2008. Evolving strategies for the management of hand-foot skin reaction
L. Di Cesare Mannelli et al. / NeuroToxicology 50 (2015) 101–107 associated with the multitargeted kinase inhibitors sorafenib and sunitinib. Oncologist 13, 1001–1011. Leighton, G.E., Rodriguez, R.E., Hill, R.G., Hughes, J., 1988. k-Opioid agonist produce antinociception after i.v.and i.c.v. but not intrathecal administration in the rat. Br. J. Pharmacol. 93, 553–560. Liu, J.Y., Park, S.H., Morisseau, C., Hwang, S.H., Hammock, B.D., Weiss, R.H., 2009. Sorafenib has soluble epoxide hydrolase inhibitory activity, which contributes to its effect profile in vivo. Mol. Cancer Ther. 8, 2193–2203. Llovet, J.M., Ricci, S., Mazzaferro, V., Hilgard, P., Gane, E., Blanc, J.F., et al., 2008. Sorafenib in advanced hepatocellular carcinoma. N. Engl. J. Med. 359, 378–390. Lo Conte, N.K., Holen, K.D., Schelman, W.R., Mulkerin, D.L., Deming, D.A., Hernan, H.R., et al., 2013. A phase I study of sorafenib, oxaliplatin and 2 days of high dose capecitabine in advanced pancreatic and biliary tract cancer: a Wisconsin oncology network study. Invest. New Drugs 31, 943–948. Mackenzie, F., Ruhrberg, C., 2012. Diverse roles for VEGF-A in the nervous system. Development 139, 1371–1380. Micheva, K.D., Taylor, C.P., Smith, S.J., 2006. Pregabalin reduces the release of synaptic vesicles from cultured hippocampal neurons. Mol. Pharmacol. 70, 467–476. Rao, R.D., Flynn, P.J., Sloan, J.A., Wong, G.Y., Novotny, P., Johnson, D.B., et al., 2008. Efficacy of lamotrigine in the management of chemotherapy-induced peripheral neuropathy: a phase 3 randomized, double-blind, placebocontrolled trial, N01C3. Cancer 112, 2802–2808. Rao, R.D., Michalak, J.C., Sloan, J.A., Loprinzi, C.L., Soori, G.S., Nikcevich, D.A., et al., 2007. Efficacy of gabapentin in the management of chemotherapyinduced peripheral neuropathy: a phase 3 randomized, double-blind, placebo-controlled, crossover trial (N00C3). Cancer 110, 2110–2118. Rashid, M.H., Ueda, H., 2002. Nonopioid and neuropathy-specific analgesic action of the nootropic drug nefiracetam in mice. J. Pharmacol. Exp. Ther. 303, 226–231. Reagan-Shaw, S., Nihal, M., Ahmad, N., 2008. Dose translation from animal to human studies revisited. FASEB J. 22, 659–661. Sakurai, M., Egashira, N., Kawashiri, T., Yano, T., Ikesue, H., Oishi, R., 2009. Oxaliplatin induced neuropathy in the rat: involvement of oxalate in cold hyperalgesia but not mechanical allodynia. Pain 147, 165–174. Shir, Y., Seltzer, Z., 1990. A-Fibers mediate mechanical hyperesthesia and allodynia and C-fibers mediate thermal hyperalgesia in a new model of causalgiform pain disorders in rats. Neurosci. Lett. 115, 62–67.
107
Sisignano, M., Baron, R., Scholich, K., Geisslinger, G., 2014. Mechanism-based treatment for chemotherapy-induced peripheral neuropathic pain. Nat. Rev. Neurol. 10, 694–707. Smith, E.M., Pang, H., Cirrincione, C., Fleishman, S., Paskett, E.D., Ahles, T., et al., 2013. Alliance for Clinical Trials in Oncology. Effect of duloxetine on pain, function, and quality of life among patients with chemotherapy-induced painful peripheral neuropathy: a randomized clinical trial. Jama 309, 1359– 1367. Smolle, E., Taucher, V., Petru, E., Haybaeck, J., 2014. Targeted treatment of ovarian cancer- the multiple - kinase - inhibitor sorafenib as a potential option. Anticancer Res. 34, 1519–1530. Stubblefield, M.D., Custodio, C.M., Kaufmann, P., 2006. Small-fiber-neuropathy associated with capecitabine (Xeloda)-induced hand–foot syndrome: a case report. J. Clin. Neuromuscul. Dis. 7, 128–132. Thompson, D.S., Greco, F.A., Spigel, D.R., 2006. Bevacizumab, erlotinib, and imatinib in the treatment of patients with advanced renal cell carcinoma: update of a multicenter phase II trial. J. Clin. Oncol. 24 (Suppl 18), 4594. Verheyen, A., Peeraer, E., Lambrechts, D., Poesen, K., Carmeliet, P., Shibuya, M., et al., 2013. Therapeutic potential of VEGF and VEGF-derived peptide in peripheral neuropathies. Neuroscience 244, 77–89. Walko, C.M., Grande, C., 2014. Management of common adverse events in patients treated with sorafenib: nurse and pharmacist perspective. Semin. Oncol. 41 (Suppl 2), S17–S28. Wilhelm, S.M., Adnane, L., Newell, P., Villanueva, A., Llovet, J.M., Lynch, M., 2008. Preclinical overview of sorafenib, a multikinase inhibitor that targets both Raf and VEGF and PDGF receptor tyrosine kinase signaling. Mol. Cancer Ther. 7, 3129–3140. Wilhelm, S.M., Carter, C., Tang, L., Wilkie, D., McNabola, A., Rong, H., et al., 2004. BAY 43-9006 exhibits broad spectrum oral antitumor activity and targets the Raf/MEK/ERK pathway and receptor tyrosine kinases involved in tumor progression and angiogenesis. Cancer Res. 64, 7099–7109. Winkler, E.A., Bell, R.D., Zlokovic, B.V., 2011. Central nervous system pericytes in health and disease. Nat. Neurosci. 14, 1398–1405. Winkler, E.A., Bell, R.D., Zlokovic, B.V., 2010. Pericyte-specific expression of PDGF beta receptor in mouse models with normal and deficient PDGF beta receptor signaling. Mol. Neurodegener. 5, 32.
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NeuroToxicology
Full Length Article
A model of neuropathic pain induced by sorafenib in the rat: Effect of dimiracetam Lorenzo Di Cesare Mannelli a,*, Mario Maresca a, Carlo Farina b,c, Michael W. Scherz c, Carla Ghelardini a a
Department of Neuroscience, Psychology, Drug Research and Child Health, - Neurofarba - Pharmacology and Toxicology Section, University of Florence, Viale G. Pieraccini, 6, 50139 Firenze, Italy Neurotune AG, Wagistrasse 27a, CH-8952 Schlieren, Switzerland c Metys Pharmaceuticals, Friedrichstrasse 6, CH-4055 Basel, Switzerland b
A R T I C L E I N F O
A B S T R A C T
Article history: Received 25 May 2015 Received in revised form 28 July 2015 Accepted 3 August 2015 Available online 5 August 2015
Background: Sorafenib is a kinase inhibitor anticancer drug whose repeated administration causes the onset of a peripheral painful neuropathy. Notably, the efficacy of common analgesic drugs is not adequate and this often leads pre-mature discontinuation of anticancer therapy. The aim of this study was to establish a rat model of sorafenib-induced neuropathic pain, and to assess the effect of the new anti-neuropathic compound dimiracetam in comparison with gabapentin, pregabalin and duloxetine. Methods: Male Sprague-Dawley rats were treated i.v. (10 mg kg 1), i.p. (10 and 30 mg kg 1) or p.o. (80 and 160 mg kg 1) with sorafenib once daily for 21 days. Pain behaviour measurements (cold plate, paw pressure, electronic von Frey) were performed on days 0, 7, 14 and 21. Results: Sorafenib lowered the paw-licking threshold to non-noxious cold stimuli on day 14 of all protocols evaluated. The i.p. administration resulted in greater efficacy than the other administration routes. Sorafenib treatments did not affect paw-withdrawal responses to non-noxious or to noxious mechanical stimuli. On day 14, dimiracetam (300 mg kg 1), gabapentin (100 mg kg 1), pregabalin (30 mg kg 1) and duloxetine (30 mg kg 1) were acutely administered p.o. in sorafenib i.p.-treated rats. A single oral dose of dimiracetam induced a statistically significant increase of the pain threshold 15 min after administration. Pregabalin induced a comparable effect, whereas gabapentin and duloxetine were ineffective. Repeated twice-daily administration of dimiracetam (150 mg kg 1 p.o.), starting on the first day of i.p sorafenib administration, significantly protected rats from sorafenib-induced decrease in the paw-licking threshold. Conclusions: A rat model of sorafenib-induced hypersensitivity to cold stimulation has been established. Dimiracetam and pregabalin are effective in prevention of sorafenib-induced neuropathy in this model. ß 2015 Elsevier Inc. All rights reserved.
Keywords: Chemotherapy-induced neuropathy Neuropathic pain Sorafenib Dimiracetam Pregabalin Pain model
1. Background Neuropathic symptoms are commonly observed in patients receiving antitumor chemotherapy, often preventing completion of the chemotherapeutic cycle (Kennedy, 2007). Chemotherapyinduced neuropathy consists mainly of sensory symptoms, rather than of motor symptoms (Cavaletti et al., 2013), and includes mechanical and cold allodynia, ongoing burning pain, tingling, and allodynic sensation in hands and feet, as well as a chronic foot/leg,
* Corresponding author. Tel.: +39 0552758395; fax: +39 0552758181. E-mail address: lorenzo.mannelli@unifi.it (L. Di Cesare Mannelli). http://dx.doi.org/10.1016/j.neuro.2015.08.002 0161-813X/ß 2015 Elsevier Inc. All rights reserved.
hand/arm numbness (Cersosimo, 2005). Platinum analogues, taxanes, vinka alkaloids, epothilones and proteosoma inhibitors have been reported to be the most predominant anticancer drug families causing peripheral neuropathy even if with different neurotoxic profiles and with several clinical manifestations (Chu et al., 2015). Besides them, sorafenib, a non-selective multikinase-inhibitor (MKI) approved for the treatment of renal cell carcinoma (RCC), hepatocellular carcinoma (HCC) and metastatic differentiated thyroid carcinoma (DTC) (Escudier et al., 2007; Llovet et al., 2008; Blair and Plosker, 2015), generates the handfoot syndrome (HFS), characterized by ulcerative dermatitis and pain on hands and feet after 3 weeks of treatment (Awada et al., 2005; Cicek et al., 2009).
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It is important to note that there is currently no effective treatment to prevent or reverse the painful condition associated to chemotherapy-induced neuropathy (Hershman et al., 2014). The unequivocal treatment of pain induced by anticancer drugs is made difficult by the several, unclear mechanisms underlying chemotherapy-induced neurotoxicity. Accordingly, the management of the sorafenib-dependent painful neuropathy occurring in HFS lacks effective treatment strategies (Walko and Grande, 2014) and, to date, the mechanisms of this adverse effect have not yet been elucidated. The management of pain in HFS is limited to topical or systemic treatments (nonsteroidal anti-inflammatory drugs, codeine and pregabalin), unable to completely control the symptom and to avoid dose modification or discontinuation of the anticancer therapy (Lacouture et al., 2008). The development of effective therapeutic strategies for the control of sorafenib-induced neuropathy is limited by both the lack of knowledge about its mechanism of neurotoxicity, and the absence of an animal model for preclinical research. The aim of the present study was to develop a rat model of sorafenib-induced neuropathic pain by evaluating the effect of different dosages and routes of administration on the pain threshold alteration evoked by mechanical and thermal noxious and non-noxious stimuli. Moreover, the efficacy of compounds usually recommended for the management of chemotherapyinduced neuropathy was evaluated. 2. Methods 2.1. Animals Male Sprague-Dawley rats (Harlan, Varese, Italy) weighing approximately 200 to 250 g at the beginning of the experimental procedure were used. Animals were housed in CeSAL (Centro Stabulazione Animali da Laboratorio, University of Florence) and used at least 1 week after their arrival. Four rats were housed per cage (size 26–41 cm); animals were fed with standard laboratory diet and tap water ad libitum, and kept at 23 1 8C with a 12 h light/dark cycle, light at 7 a.m. All animal manipulations were carried out according to the European Community guidelines for animal care (DL 116/92, application of the European Communities Council Directive of 24 November 1986 (86/609/EEC). The ethical policy of the University of Florence complies with the Guide for the Care and Use of Laboratory Animals of the US National Institutes of Health (NIH Publication No. 85-23, revised 1996; University of Florence assurance number: A5278-01). Formal approval to conduct the experiments described was obtained from the Italian Ministry of Health (N854/ 2014-B) and from the Animal Subjects Review Board of the University of Florence. Experiments involving animals have been reported according to ARRIVE guidelines (Kilkenny et al., 2010). 2.2. Drug administration Sorafenib (APIChem Technology Co., Ltd, Hangzhou, China) was dissolved in a vehicle constituted by 1% ethanol, 1% Cremophor, 98% saline for the intraperitoneal (i.p.) and intravenously (i.v.; in the tail vein) injections and in carboxymethylcellulose for the per os (p.o.) treatment. Gabapentin, pregabalin, duloxetine (SigmaAldrich, Milan, Italy) and dimiracetam (Neurotune AG, Schlieren, Switzerland) were dissolved in water. Control rats were treated with an equal volume of vehicles. Sorafenib was administered i.p. and p.o once daily for 21 days and i.v. for 14 days. Gabapentin (100 mg kg 1), pregabalin (30 mg kg 1), duloxetine (30 mg kg 1) and dimiracetam (300 mg kg 1) were injected once on day 14 of the sorafenib treatment (i.p.) to evaluate their acute effect. In the preventive protocol dimiracetam (150 mg kg 1) and pregabalin (15 mg kg 1) were given twice daily (in the morning and in the
evening) p.o. for 14 days starting from first day in which sorafenib was injected. In the preventive protocol 10 mg kg 1 sorafenib was injected daily i.p. for 14 days. 2.3. Paw pressure test The nociceptive threshold in the rat was determined by an analgesimeter (Ugo Basile, Varese, Italy), according to the method described by (Leighton et al., 1988). Briefly, a constantly increasing pressure was applied to a small area of the dorsal surface of the hind paw using a blunt conical probe by a mechanical device. Mechanical pressure was increased until vocalization or a withdrawal reflex occurred while rats were lightly restrained. Vocalization or withdrawal reflex thresholds were expressed in grams (g). Rats scoring below 40 g or over 75 g during the test before drug administration were rejected (25% of all rats). Mechanical pressure application was stopped at 120 g. 2.4. Von Frey test The animals were placed in 20 cm 20 cm plexiglas boxes equipped with a metallic mesh floor, 20 cm above the bench. A habituation of 15 min was allowed before the test. An electronic Von Frey hair unit (Ugo Basile, Varese, Italy) was used: the withdrawal threshold was evaluated by applying force ranging from 0 to 50 grams with a 0.2 gram accuracy. Punctuate stimulus was delivered to the mid-plantar area of each anterior paw from below the mesh floor through a plastic tip and the withdrawal threshold was automatically displayed on the screen. Paw sensitivity threshold was defined as the minimum pressure required to elicit a robust and immediate withdrawal reflex of the paw. Voluntary movements associated with locomotion were not taken as a withdrawal response. Stimuli were applied on each anterior paw with an interval of 5 s. The measure was repeated 5 times and the final value was obtained by averaging the 5 measures (Sakurai et al., 2009). 2.5. Cold plate test The animals were placed in a stainless box (12 cm 20 cm 10 cm) with a cold plate as floor. The temperature of the cold plate was kept constant at 4 8C 1 8C. Pain-related behaviours (i.e. lifting and licking of the hind paw) were observed and the time (s) of the first sign was recorded. The cut-off time of the latency of paw lifting or licking was set at 60 s. 2.6. Statistical analysis Behavioral measurements were performed on 10 rats for each treatment carried out in 2 different experimental sets. Results were expressed as means s.e.m. and the analysis of variance was performed by one way ANOVA. A Bonferroni’s significant difference procedure was used as post-hoc comparison. P values of less than 0.05 or 0.01 were considered significant. Data were analyzed using the ‘‘Origin 9’’ software (OriginLab, Northampton, USA). 3. Results Sorafenib was i.v. infused (10 mg kg 1) daily for 14 days, while the i.p. (10 or 30 mg kg 1) and p.o. (80 or 160 mg kg 1) administrations were repeated daily for 21 days. Behavioural measurements were performed on days 0, 7, 14 and 21. In Figure 1, the response to a cold non-noxious stimulus (Cold plate test) is shown. Sorafenib i.v. (10 mg kg 1) significantly lowered rats’ licking latency on day 14 (20.5 2.5 s vs 28.4 2.0 s of vehicletreated group) (Figure 1a). The i.p. injection of 10 and 30 mg kg-1 of
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Fig. 1. Thermal non-noxious stimulus, Cold plate test. The response to a thermal stimulus was evaluated by cold plate test measuring the latency (seconds) to painrelated behaviors (lifting or licking of the paw). Rats were intravenously, intraperitoneally or orally treated once daily with sorafenib (10, 30, 80 and 160 mg kg 1). Behavioural test was performed on day 0, 7, 14 and 21 (only for i.p. and p.o. administrations). Control animals were treated with vehicles. Each value represents the mean of 10 rats per group, performed in 2 different experimental sets. *P < 0.01 versus vehicle treated rats.
sorafenib significantly reduced the time response to a cold stimulus on day 14 (12.1 2.1 s and 12.2 0.8 s, respectively, vs 28.4 2.0 s of vehicle) and on day 21 (12.0 3.6 s and 11.3 0.6 s, respectively, vs 29.0 0.7 s of vehicle) (Figure 1b). Moreover, the p.o. administration of sorafenib reduced the pain threshold on day 21, as shown in Figure 1c. The effects induced by 80 or 160 mg kg-1 of sorafenib i.p. were comparable: 20.0 3.4 s and 18.0 1.8 s, respectively, vs 29.0 0.7 s of vehicle-treated rats. The response to a mechanical non-noxious stimulus was evaluated by the Von Frey test (Fig. 2). Sorafenib i.v. did not significantly alter the withdrawal threshold after 7 and 14 days of treatment (Fig. 2a). The i.p.-treated group (30 mg kg 1) showed a decreased threshold on days 14 and 21 (24.7 3.4 g and
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Fig. 2. Mechanical non-noxious stimulus, Von Frey test. The withdrawal threshold was evaluated by Von Frey apparatus as a response evoked by a mechanical stimulus. Rats were intravenously, intraperitoneally or orally treated with sorafenib (10, 30, 80 or 160 mg kg 1) and behavioural measurements were assessed on day 0, 7, 14 and 21 (only for i.p. and p.o. administrations). Control animals were treated with vehicles or saline. Each value represents the mean of 10 rats per group, performed in 2 different experimental sets.
25.7 2.1 g, respectively, vs 31.9 2.0 g of vehicle) without reaching statistical significance (Fig. 2b). The p.o. treatment did not modify the response evoked by a mechanical non-noxious stimulus (Fig. 2c). Fig. 3 shows the animal sensitivity to a mechanical noxious stimulus measured by the Paw pressure test. The repeated administration of sorafenib (i.v., i.p. or p.o.) did not evoke significant hypersensitivity. Focusing on the i.p. administration protocol and on the measurements performed by cold non-noxious stimuli, the responsiveness of sorafenib-induced pain to a common pain reliever was evaluated. On day 14 of sorafenib i.p. administration, 100 mg kg 1 gabapentin, 30 mg kg 1 pregabalin, 30 mg kg 1 duloxetine and 300 mg kg 1 dimiracetam were acutely administered p.o. and the pain threshold was evaluated over time (Cold
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Fig. 4. Thermal non-noxious stimulus, Cold plate test. The response to a thermal stimulus was evaluated by cold plate test measuring the latency (seconds) to painrelated behaviours (lifting or licking of the paw). Rats were daily intraperitoneally treated with sorafenib 10 mg kg 1 and behaviour was measured on day 14. Gabapentin 100 mg kg 1, pregabalin 30 mg kg 1, duloxetine 30 mg kg 1 were p.o. administered and measurements were assessed 15, 30, 45 and 60 min after injection. Control rats were treated with vehicle. Each value represents the mean of 10 rats per group, performed in 2 different experimental sets. ^P < 0.05 versus sorafenib + vehicle treated rats.
Fig. 3. Mechanical noxious stimulus, Paw pressure test. Rats were intravenously, intraperitoneally or orally treated once daily with sorafenib (10, 30, 80 and 160 mg kg 1), and the sensibility to a mechanical stimulus was measured by Paw pressure test on day 0, 7, 14 and 21 (only for i.p. and p.o. administrations). Control animals were treated with vehicles or saline. Each value represents the mean of 10 rats per group, performed in 2 different experimental sets.
plate test). As depicted in Fig. 4, a single oral dose of dimiracetam significantly increased the licking latency 15 min after injection (19.8 1.5 s). The efficacy was comparable to that induced by pregabalin (19.0 1.7 s). Gabapentin and duloxetine were ineffective. To assess the preventive effect of repeated doses of dimiracetam, a subchronic treatment protocol was performed. Dimiracetam was administered twice daily at the dose of 150 mg kg 1 p.o. from the first day in which sorafenib (10 mg kg 1 i.p. daily) was injected. Pregabalin (15 mg kg 1 p.o. twice daily) was used as reference compound. On day 14, the pain threshold was evaluated by the Cold plate test at time 0, before dimiracetam or gabapentin morning administration (Fig. 5). Dimiracetam-treated animals showed a licking latency significantly higher (sorafenib + dimiracetam; 24.3 0.8 s) than sorafenib + vehicle-treated rats (14.8 1.3 s). The effect of dimiracetam was unmodified by a new administration
Fig. 5. Effect of dimiracetam-repeated treatment, Cold plate test. Rats were daily intraperitoneally treated with sorafenib 10 mg kg 1 and dimiracetam (150 mg kg 1 p.o. twice daily), in comparison to pregabalin (15 mg kg 1 p.o. twice daily) or vehicle. On day 14, the response to a thermal stimulus was evaluated by cold plate test measuring the latency (seconds) to pain-related behaviours (lifting or licking of the paw). Measurements were performed before dimiracetam or pregabalin treatments (time 0) and over time after the morning treatment. Control rats were treated with vehicle. Each value represents the mean of 10 rats per group, performed in 2 different experimental sets. ^P < 0.05 and ^^P < 0.01 versus sorafenib + vehicle treated rats.
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and it was still significant 48 h after treatment. The effect of pregabalin was lower (20.9 0.9 s) and shorter lasting (24 h). 4. Discussion The present results describe a model of sorafenib-induced neuropathic pain in the rat. Repeated treatment with sorafenib by different routes of administration (i.v., i.p. and p.o.) induces hypersensitivity to thermal (cold) non-noxious, but not to mechanical noxious or non-noxious stimuli. The oral dose usually employed in clinic (400 mg twice daily; Walko and Grande, 2014) is comparable to the lower dose in the rat (80 mg kg 1) studied here, as calculated by the body surface area (BSA) normalization method (Reagan-Shaw et al., 2008). The high dose (160 mg kg 1) has a similar neuropathic effect. The i.v. and i.p. administrations of sorafenib also exert a strong decrease of pain threshold in response to a cold stimulus. Notably, sorafenib i.p. (10 and 30 mg kg 1) causes a greater hypersensitivity in comparison to the oral treatments of 80 mg kg 1 or 160 mg kg 1. Although no significant alteration in response to a mechanical noxious or non-noxious stimulus are evident, 10 mg kg 1 sorafenib i.v. and 30 mg kg 1 i.p. show a tendency to lower the paw withdrawal threshold in response to a mechanical non-noxious stimulus. Sorafenib is a non-selective multi-kinase-inhibitor approved for the treatment of renal cell carcinoma (RCC), hepatocellular cell carcinoma (HCC) and metastatic differentiated thyroid carcinoma (DTC) by the US Food and Drug Administration (Escudier et al., 2007; Llovet et al., 2008; Blair and Plosker, 2015). The efficacy of sorafenib has also been demonstrated, alone or in association, in clinical phase I/II study and in patients with metastatic breast cancer (Baselga et al., 2012). Several clinical studies highlighted the onset of a variety of side effects, during the treatment with sorafenib and other MKIs such as Sunitinib (Lacouture et al., 2008; Smolle et al., 2014). Among them, the development of painful neuropathic syndrome has been frequently reported (Awada et al., 2005; Abou-Alfa et al., 2006). In particular, Lo Conte and colleagues described HFS, also called palmar-plantar erythrodysesthesia (PPE) as the most limiting adverse effect recurring in 30% of patients treated with sorafenib 400 mg b.i.d. p.o. (Lo Conte et al., 2013). Tingling, numbness and tightness on hands and feet are the earliest symptoms representing the 1st grade of toxicity. Within few days the syndrome evolves in dysesthesia and severe pain, the main clinical manifestations of the 2nd and 3rd grades of HFS, forcing patients to interrupt chemotherapy (Lacouture et al., 2008; Walko and Grande, 2014). Clinical data suggest that a small-fiber neuropathy could be the cause of pain and dysesthesia in HFS (Stubblefield et al., 2006). The preferential damage to the small diameter, myelinated and unmyelinated fibers could directly alter the afferent thermal (hot and cold) and nociceptive transmission (Al-Shekhlee et al., 2002). Our data suggest sorafenib may specifically interfere with the nociceptive C-fibers, normally involved in thermal stimuli transmission (Shir and Seltzer, 1990), as we observe the development of thermal but not mechanical hypersensitivity in the rat. In particular, we evaluated the response to cold non noxious stimuli since cold allodynia has been associated to several types of neuropathy induced by anticancer drug (Sisignano et al., 2014). On the contrary, hypersensitivity to heat is common in animal models of traumatic nerve injury pain but it is very minor or absent in rat models of chemotherapy-induced as well as in patients suggesting that the pathophysiological mechanisms responsible for neuropathic pain are at least partly different depending on the cause of the nerve damage (Bennett, 2010). Moreover, some author suggests the loss of heat sensitivity as a hallmark symptom due to preferential damage to myelinated primary afferent sensory nerve fibers in the presence or absence of
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demyelination in chemotherapy-induced neuropathy (Han and Smith, 2013). Sorafenib seems to evoke electively a cold hypersensitivity even if the mechanism by which sorafenib affects fiber transmission and, in turn, evokes the onset of painful neuropathy is not well established. Sorafenib was initially designed as a potent inhibitor of Raf serine/threonine kinase isoforms. Nevertheless, its anti-angiogenesis and anti-proliferative effects are primarily due to the blockade of VEGF receptors (VEGFR-1, VEGFR-2 and VEGFR-3) and PDGF receptors (PDGFR-b, in particular), considered the initiators of the signaling pathway of tumor vessel formation. The inhibition of cKIT and Flt3, two receptor tyrosine kinases, contributes to the sorafenib anti-angiogenesis properties (Erber et al., 2004; Wilhelm et al., 2004; Wilhelm et al., 2008) as well as the inhibitory properties against the soluble epoxide hydrolase may participate in sorafenib efficacy (Liu et al., 2009). Since the inhibition of PDGFR or VEGFR alone does not result in HFS provoked by MKIs, both VEGFRs and PDGFRs blockade seems to be essential for the neurotoxicity (Thompson et al., 2006). VEGF has several functions in neural cells independent from its role in vessels. It promotes neurogenesis, neuronal migration and survival, axon guidance and synaptic plasticity (Mackenzie and Ruhrberg, 2012). Furthermore, VEGF exerts neuroprotective effects in diabetic- and paclitaxelinduced sensory neuropathy via the up regulation of BCL2 protein (Verheyen et al., 2013). On the other hand, the inhibition of VEGFR pathway as well as the reduction of VEGF levels may cause neuronal damage, affecting BCL2 protein expression (Verheyen et al., 2013). PDGFRs are generally expressed on the surface of pericytes, one of the main cell components of the blood brain barrier (BBB) together with astrocytes and endothelial cells so forming the neurovascular unit (Winkler et al., 2010). PDGFR stimulation regulates pericyte recruitment and enhances their proliferation (Winkler et al., 2011) contributing to the BBB homeostasis maintenance. On the other hand, PDGFR inhibition promotes pericyte degeneration, which, in turn, may be the cause of the BBB disruption and the starting point of neuroinflammatory and neurodegenerative processes (Dalkara et al., 2011). Moreover, also c-KIT and Flt-3 receptor are involved in neurotrophic and neuroprotective signals (Dhandapani et al., 2005) even if the effect of their inhibition in pain sensitivity has not yet been investigated. The lack of knowledge about the mechanisms of sorafenib neurotoxicity involves a poverty of therapeutic options. Currently, the prophylactic approach is aimed to prevent dermatological symptoms. For the 1st grade of toxicity, urea or salicylic acid creams or 0.05% clobetasol are prescribed for the treatment of dermatological symptoms. Later, according to the onset of painful signs, topic 2% lidocaine is suggested. Progressively, when painful symptoms become more intense, systemic pain relievers (NSAIDs, codeine or pregabalin) are recommended. However, for the high grades of toxicity a dose reduction of sorafenib by about 50% for a 7 to 28 day period should be considered. The discontinuation of therapy may be suggested until regression to the 1st grade of toxicity (Lacouture et al., 2008). The inadequacy of care for neuropathic sensory symptoms caused by the use of sorafenib (Walko and Grande, 2014), fits into the complicated context of the prevention and treatment of neuropathies induced by chemotherapy agents. To date, compounds used for the treatment of other neuropathies such as diabetic neuropathy and post-herpetic neuropathy, are commonly employed also in the management of chemotherapy-induced neuropathies even though their different etiopathology. As reported by Hershman et al. (2014), no agents are recommended for the prevention of chemotherapy-induced neuropathies since the paucity of high-quality, consistent evidence. Duloxetine has been reported to decrease pain, numbness and tingling in oxaliplatin – but not in paclitaxel-treated patients (Smith et al.,
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2013), two small trials failed to demonstrate the efficacy of tricyclic antidepressant in decreasing painful symptoms during taxanes, platinum or Vinca alkaloid treatments (Hammack et al., 2002; Kautio et al., 2008). Furthermore, the use of gabapentin has been demonstrated inconclusive in chemotherapy-induced neuropathy (Rao et al., 2007; Rao et al., 2008), but given the limited other treatment options and the utility of this molecule (or that of related drugs like pregabalin) in other neuropathic pain conditions encourages its clinical use (Hershman et al., 2014). To the best of our knowledge no clinical data are available about the treatment of sorafenib neurotoxicity. In the preclinical model of sorafenib-induced neuropathic pain developed in the present research gabapentin and duloxetine are ineffective. Interestingly, the racetam derivative dimiracetam shows an efficacy comparable to that induced by pregabalin. A single administration of dimiracetam counteracts established pain induced by sorafenib. Moreover, the association dimiracetamsorafenib in a repeated-treatment protocol significantly reduced hypersensitivity showing a longer lasting effect than pregabalin. Racetams, also called nootropics, are a family of 2-pyrrolidinone derivatives originally profiled as cognition enhancers. A report of efficacy of nefiracetam against tactile and thermal hyperalgesia in mice (Rashid and Ueda, 2002) suggested that chemical modifications of the racetam structure might confer powerful antineuropathic pain activity. Dimiracetam was active on trauma-dependent neuropathic pain induced by chronic constriction injury of the sciatic nerve and on diabetic neuropathy retaining at the same time its outstanding efficacy of improving cognition in animal models (Farina et al., 2008). Recently we have reported that dimiracetam, acutely or repeatedly administered, is very effective in models of chemotherapy-induced neuropathic pain induced by the anticancer agent oxaliplatin or by antiretroviral drugs with an excellent tolerability profile (Fariello et al., 2014). Dimiracetam shares with pregabalin an effect on the glutamatergic system since pregabalin reduces the release of synaptic vesicles from glutamatergic terminals (Micheva et al., 2006) and dimiracetam counteracts the NMDA-induced release of glutamate in synaptosomal preparations from rat spinal cord (Fariello et al., 2014). This evidence suggests the central nervous system as a relevant site for the dimiracetam’s mechanism of action. Dimiracetam is currently in clinical development for treatment and/or prevention of chemotherapy-induced peripheral neuropathy. 5. Conclusions Sorafenib repeated administrations in the rat induce the onset of sensitive neuropathy characterized by hypersensitivity to thermal (cold) stimuli. The pain relieving efficacy of dimiracetam is shown, suggesting this compound may be a promising treatment for sorafenib-induced neuropathic pain. Conflict of interests MS and CF are employees of Metys Pharmaceuticals. CG performed the work in the framework of a research contract with Neurotune AG. This study was performed without any financial or other contractual agreements that may cause conflict of interest. The other authors declare no conflict of interests. Author’s contribution LDCM and MM performed the experimental tests; LDCM, CG and CF performed the statistical analysis of data; LDCM, CG, CF and MS participated in the design of the study; LDCM, MM, CG, CF and MS conceived of the study, and participated in its coordination
and helped to draft the manuscript. All authors read and approved the final manuscript. Acknowledgements This research was funded by the Italian Ministry of Instruction, University and Research (MIUR), University of Florence and Neurotune AG. References Abou-Alfa, G.K., Schwartz, L., Ricci, S., Amadori, D., Santoro, A., Figer, A., Phase, I.I., 2006. study of sorafenib in patients with advanced hepatocellular carcinoma. J. Clin. Oncol. 24, 4293–4300. Al-Shekhlee, A., Chelimsky, T.C., Preston, D.C., 2002. Review: small-fiber neuropathy. Neurologist 8, 237–253. Awada, A., Hendlisz, A., Gil, T., Bartholomeus, S., Mano, M., de Valeriola, D., et al., 2005. Phase I safety and pharmacokinetics of BAY 43-9006 administered for 21 days on/7 days off in patients with advanced, refractory solid tumours. Br. J. Cancer 92, 1855–1861. Baselga, J., Segalla, J.G., Roche´ , H., Del Giglio, A., Pinczowski, H., Ciruelos, E.M., 2012. Sorafenib in combination with capecitabine: an oral regimen for patients with HER2-negative locally advanced or metastatic breast cancer. J. Clin. Oncol. 30, 1484–1491. Bennett, G.J., 2010. Pathophysiology and animal models of cancer-related painful peripheral neuropathy. Oncologist 15 (Suppl. 2), 9–12. Blair, H.A., Plosker, G.L., 2015. Sorafenib: a review of its use in patients with radioactive iodine-refractory, metastatic differentiatedthyroid carcinoma. Target Oncol. 10, 171–178. Cavaletti, G., Cornblath, D.R., Merkies, I.S., Postma, T.J., Rossi, E., Frigeni, B., et al., 2013. The chemotherapy-induced peripheral neuropathy outcome measures standardization study: from consensus to the first validity and reliability findings. Ann. Oncol. 24, 454–462. Cersosimo, R.J., 2005. Oxaliplatin-associated neuropathy: a review. Ann. Pharmacother. 39, 128–135. Chu, S.H., Lee, Y.J., Lee, E.S., Geng, Y., Wang, X.S., Cleeland, C.S., 2015. Current use of drugs affecting the central nervous system for chemotherapy-induced peripheral neuropathy in cancer patients: a systematic review. Support Care Cancer 23, 513–524. Cicek, D., Kandi, B., Dagli, F.A., Karaoglu, A., Haligur, B.D., 2009. Pre-treatment global quality of health predicts progression free survival in metastatic kidney cancer patients treated with sorafenib or sunitinib. J. Can. Res. Clin. Oncol. 135, 61–67. Dalkara, T., Gursoy-Ozdemir, Y., Yemisci, M., 2011. Brain microvascular pericytes in health and disease. Acta Neuropathol. 122, 1–9. Dhandapani, K.M., Wade, F.M., Wakade, C., Mahesh, V.B., Brann, D.W., 2005. Neuroprotection by stem cell factor in rat cortical neurons involves AKT and NFkappaB. J. Neurochem. 95, 9–19. Erber, R., Thurnher, A., Katsen, A.D., Groth, G., Kerger, H., Hammes, H.P., et al., 2004. Combined inhibition of VEGF and PDGF signaling enforces tumor vessel regression by interfering with pericyte-mediated endothelial cell survival mechanisms. FASEB J. 18, 338–340. Escudier, B., Eisen, T., Stadler, W.M., Szczylik, C., Oudard, S., Siebels, M., et al., 2007. Sorafenib in advanced clear-cell renal-cell carcinoma. N. Engl. J. Med. 356, 125–134. Fariello, R.G., Ghelardini, C., Di Cesare Mannelli, L., Bonanno, G., Pittaluga, A., Milanese, M., et al., 2014. Broad spectrum and prolonged efficacy of dimiracetam in models of neuropathic pain. Neuropharmacology 81, 85–94. Farina, C., Gagliardi, S., Ghelardini, C., Martinelli, M., Norcini, M., Parini, C., Petrillo, P., Ronzoni, S., 2008. Synthesis and biological evaluation of novel dimiracetam derivatives useful for the treatment of neuropathic pain. Bioorg. Med. Chem. 16, 3224–3232. Hammack, J.E., Michalak, J.C., Loprinzi, C.L., Sloan, J.A., Novotny, P.J., Soori, G.S., et al., 2002. Phase III evaluation of nortriptyline for alleviation of symptoms of cis-platinum-inducedperipheral neuropathy. Pain 98, 195–203. Han, Y., Smith, M.T., 2013. Pathobiology of cancer chemotherapy-induced peripheral neuropathy (CIPN). Front. Pharmacol. 4, 156, http://dx.doi.org/ 10.3389/fphar.2013.00156. Hershman, D.L., Lacchetti, C., Dworkin, R.H., Lavoie Smith, E.M., Bleeker, J., Cavaletti, G., et al., 2014. Prevention and management of chemotherapyinduced peripheral neuropathy in survivors of adult cancers: American Society of Clinical Oncology clinical practice guideline. J. Clin. Oncol. 32, 1941–1967. Kautio, A.L., Haanpa¨a¨, M., Saarto, T., Kalso, E., 2008. Amitriptyline in the treatment of chemotherapy-induced neuropathic symptoms. J. Pain Symptom Manage. 35, 31–39. Kennedy, J.D., 2007. Neuropathic pain: molecular complexity underlies continuing unmet medical need. J. Med. Chem. 50, 2547–2556. Kilkenny, C., Browne, W.J., Cuthill, I.C., Emerson, M., Altman, D.G., 2010. Improving bioscience research reporting: The ARRIVE guidelines for reporting animal research. J. Pharmacol. Pharmacother. 1, 94–99. Lacouture, M.E., Wu, S., Robert, C., Atkins, M.B., Kong, H.H., Guitart, J., et al., 2008. Evolving strategies for the management of hand-foot skin reaction
L. Di Cesare Mannelli et al. / NeuroToxicology 50 (2015) 101–107 associated with the multitargeted kinase inhibitors sorafenib and sunitinib. Oncologist 13, 1001–1011. Leighton, G.E., Rodriguez, R.E., Hill, R.G., Hughes, J., 1988. k-Opioid agonist produce antinociception after i.v.and i.c.v. but not intrathecal administration in the rat. Br. J. Pharmacol. 93, 553–560. Liu, J.Y., Park, S.H., Morisseau, C., Hwang, S.H., Hammock, B.D., Weiss, R.H., 2009. Sorafenib has soluble epoxide hydrolase inhibitory activity, which contributes to its effect profile in vivo. Mol. Cancer Ther. 8, 2193–2203. Llovet, J.M., Ricci, S., Mazzaferro, V., Hilgard, P., Gane, E., Blanc, J.F., et al., 2008. Sorafenib in advanced hepatocellular carcinoma. N. Engl. J. Med. 359, 378–390. Lo Conte, N.K., Holen, K.D., Schelman, W.R., Mulkerin, D.L., Deming, D.A., Hernan, H.R., et al., 2013. A phase I study of sorafenib, oxaliplatin and 2 days of high dose capecitabine in advanced pancreatic and biliary tract cancer: a Wisconsin oncology network study. Invest. New Drugs 31, 943–948. Mackenzie, F., Ruhrberg, C., 2012. Diverse roles for VEGF-A in the nervous system. Development 139, 1371–1380. Micheva, K.D., Taylor, C.P., Smith, S.J., 2006. Pregabalin reduces the release of synaptic vesicles from cultured hippocampal neurons. Mol. Pharmacol. 70, 467–476. Rao, R.D., Flynn, P.J., Sloan, J.A., Wong, G.Y., Novotny, P., Johnson, D.B., et al., 2008. Efficacy of lamotrigine in the management of chemotherapy-induced peripheral neuropathy: a phase 3 randomized, double-blind, placebocontrolled trial, N01C3. Cancer 112, 2802–2808. Rao, R.D., Michalak, J.C., Sloan, J.A., Loprinzi, C.L., Soori, G.S., Nikcevich, D.A., et al., 2007. Efficacy of gabapentin in the management of chemotherapyinduced peripheral neuropathy: a phase 3 randomized, double-blind, placebo-controlled, crossover trial (N00C3). Cancer 110, 2110–2118. Rashid, M.H., Ueda, H., 2002. Nonopioid and neuropathy-specific analgesic action of the nootropic drug nefiracetam in mice. J. Pharmacol. Exp. Ther. 303, 226–231. Reagan-Shaw, S., Nihal, M., Ahmad, N., 2008. Dose translation from animal to human studies revisited. FASEB J. 22, 659–661. Sakurai, M., Egashira, N., Kawashiri, T., Yano, T., Ikesue, H., Oishi, R., 2009. Oxaliplatin induced neuropathy in the rat: involvement of oxalate in cold hyperalgesia but not mechanical allodynia. Pain 147, 165–174. Shir, Y., Seltzer, Z., 1990. A-Fibers mediate mechanical hyperesthesia and allodynia and C-fibers mediate thermal hyperalgesia in a new model of causalgiform pain disorders in rats. Neurosci. Lett. 115, 62–67.
107
Sisignano, M., Baron, R., Scholich, K., Geisslinger, G., 2014. Mechanism-based treatment for chemotherapy-induced peripheral neuropathic pain. Nat. Rev. Neurol. 10, 694–707. Smith, E.M., Pang, H., Cirrincione, C., Fleishman, S., Paskett, E.D., Ahles, T., et al., 2013. Alliance for Clinical Trials in Oncology. Effect of duloxetine on pain, function, and quality of life among patients with chemotherapy-induced painful peripheral neuropathy: a randomized clinical trial. Jama 309, 1359– 1367. Smolle, E., Taucher, V., Petru, E., Haybaeck, J., 2014. Targeted treatment of ovarian cancer- the multiple - kinase - inhibitor sorafenib as a potential option. Anticancer Res. 34, 1519–1530. Stubblefield, M.D., Custodio, C.M., Kaufmann, P., 2006. Small-fiber-neuropathy associated with capecitabine (Xeloda)-induced hand–foot syndrome: a case report. J. Clin. Neuromuscul. Dis. 7, 128–132. Thompson, D.S., Greco, F.A., Spigel, D.R., 2006. Bevacizumab, erlotinib, and imatinib in the treatment of patients with advanced renal cell carcinoma: update of a multicenter phase II trial. J. Clin. Oncol. 24 (Suppl 18), 4594. Verheyen, A., Peeraer, E., Lambrechts, D., Poesen, K., Carmeliet, P., Shibuya, M., et al., 2013. Therapeutic potential of VEGF and VEGF-derived peptide in peripheral neuropathies. Neuroscience 244, 77–89. Walko, C.M., Grande, C., 2014. Management of common adverse events in patients treated with sorafenib: nurse and pharmacist perspective. Semin. Oncol. 41 (Suppl 2), S17–S28. Wilhelm, S.M., Adnane, L., Newell, P., Villanueva, A., Llovet, J.M., Lynch, M., 2008. Preclinical overview of sorafenib, a multikinase inhibitor that targets both Raf and VEGF and PDGF receptor tyrosine kinase signaling. Mol. Cancer Ther. 7, 3129–3140. Wilhelm, S.M., Carter, C., Tang, L., Wilkie, D., McNabola, A., Rong, H., et al., 2004. BAY 43-9006 exhibits broad spectrum oral antitumor activity and targets the Raf/MEK/ERK pathway and receptor tyrosine kinases involved in tumor progression and angiogenesis. Cancer Res. 64, 7099–7109. Winkler, E.A., Bell, R.D., Zlokovic, B.V., 2011. Central nervous system pericytes in health and disease. Nat. Neurosci. 14, 1398–1405. Winkler, E.A., Bell, R.D., Zlokovic, B.V., 2010. Pericyte-specific expression of PDGF beta receptor in mouse models with normal and deficient PDGF beta receptor signaling. Mol. Neurodegener. 5, 32.