- Email: [email protected]
Drug Repurposing: New Treatments for Zika Virus Infection?
TRMOME 1179 No. of Pages 3
Spotlight
Drug Repurposing: New Treatments for Zika Virus Infection? 1,2,
Feixiong Cheng, * James L. Murray,3 and Donald H. Rubin4,5,6 To date, no antiviral agents have been approved for treating Zika virus (ZIKV) infection. Two recent drug-repurposing studies published in Cell Host & Microbe and Nature Medicine demonstrated that screening FDA-approved drugs for antiviral activity is a promising strategy for identifying therapeutics with novel activity against ZIKV infection. Zika virus (ZIKV), a mosquito-borne flavivirus, is associated with severe birth defects and Guillain–Barré syndrome [1]. It is estimated that 1.5 million people have been infected by ZIKV in Brazil after a large outbreak in late 2014, with more than 3500 cases of microcephaly being reported between October 2015 and January 2016 [1]. As of August 24, 2016, 2517 cases had been reported in the United States, including 22 sexually transmitted cases (www.cdc.gov/zika/geo/ united-states.html). In February of 2016, the World Health Organization declared the ZIKV pandemic a Public Health Emergency of International Concern. However, there are no approved therapies to prevent and treat ZIKV infection. Traditional antiviral drug-discovery pipelines involve complex, expensive, and time-consuming processes. The efficacy of pharmaceutical agents targeting viral proteins may be limited because of the emergence of resistant viruses and the potential for untoward side effects [2]. The prospect of drug repurposing, in other words finding new indications for existing
FDA-approved drugs, is emerging as a promising alternative to expedite drug development for infectious diseases [3]. Drug repurposing is especially important for combating rapidly spreading infectious diseases, such as hepatitis C virus [4] and Ebola virus [5,6]. Thus, the systematic screening of FDA-approved drugs may reveal novel agents for treating ZIKV infection [7,8].
one of three different ZIKV strains: PRVABC59 (2015 Puerto STRAIN), FSS13025 (2010 Cambodian strain), and MR766 (1947 Ugandan strain). Using expression of ZIKV protein NS1 as a read-out, Xu et al. further found that two compounds (niclosamide and PHA690509) substantially suppressed ZIKV infection in SNB-19 cells. PHA-690509, a cyclin-dependent kinase inhibitor (CDKi), is under investigation for antiviral activity against diverse viruses [8]. Based on these observations, they identified nine additional hits that suppressed ZIKV infection in SNB-19 cells by examining 27 chemical structurally diverse CDKis. Finally, they further showed that combining treatment with emricasan and PHA-690509 showed similar anti-ZIKV activity compared to either agent alone. However, treatment of PRVABC59-infected hNPCs with emricasan for 72 h followed by niclosamide treatment for 48 h led to ZIKV-negative hNPCs. This suggested that greater ZIKV inhibition might be possible with a treatment combination of emricasan and niclosamide.
Barrows and colleagues [7] screened a library of 774 FDA-approved drugs for efficacy in blocking infection of human HuH-7 hepatocyte cells by a newly isolated ZIKV strain (ZIKV MEX_I_7). They identified 24 potential drugs with validated anti-ZIKV activities, such as ivermectin, mycophenolic acid (MPA), and daptomycin [7]. Specifically, MPA and daptomycin showed particularly high anti-ZIKV activity, with half-maximal effective concentrations (EC50) ranging from 0.1 to 1.0 mM. They further demonstrated that some of these drugs could inhibit ZIKV infection in multiple human cell types, including human cervical, placental, and neural stem cell lines, indicating stable activity against ZIKV. However, the authors did not identify the mechanism-of-action (MoA) for the In summary, the systematic screening of anti-ZIKV activities, in contrast to a previ- FDA-approved drugs highlights emerging avenues for treating ZIKV infection. Howous drug-repurposing study [5]. ever, the MoAs of the identified hits were Xu et al. systematically screened over not explored in either study [7,8]. An inte6000 compounds using a high-through- grated, systems biology-based approach put screening approach that quantified that incorporates drug–target networks, caspase-3 activity and cell viability in virus–host interactomes, and drug microhuman neural progenitor cells (hNPCs) array data may serve as an alternative infected with a prototypic ZIKV strain, approach for identifying anti-ZIKV MoAs MR766 [8]. These compounds included [6]. As shown in Figure 1, recently identi2816 FDA-approved drugs, 2000 drugs fied [6] crosstalk pathways (e.g., pro-apoin clinical trials, and 1280 pharmacologi- ptotic and cell-cycle pathways) between cally active compounds. The authors iden- cancer and viral replication may explain tified over 100 compounds that inhibited why cancer drugs (bortezomib, sorafenib, ZIKV-induced caspase-3 activity in SNB- and niclosamide) often show anti-ZIKV 19 cells. Emricasan, a pan-caspase inhib- activity. For example, niclosamide, an itor, was the most potent anti-ZIKV drug, FDA-approved drug for treating cestode with half-maximal inhibitory concentra- infections in both humans and domestic tions ranging from 0.13 to 0.19 mM in both livestock, has shown broad-spectrum activity potentially via caspase-activity and cell-viability assays. anticancer These experiments were conducted in inhibition of oxidative phosphorylation SNB-19 glioblastoma cells infected with [9]. In addition, bortezomib, an
Trends in Molecular Medicine, Month Year, Vol. xx, No. yy
1
TRMOME 1179 No. of Pages 3
OH HO
Biosynthesis: Guanosine nucleode synthesis
Cytoplasm
O O
O
O
N
O
Mycophenolic acid
NADH
OH B OH
H N
N H
O
N
Bortezomib
NAD+
IMPDH Mitochondria
Inhibitors of Zika Virus (ZIKV)
Pro-apoptoc pathway
Proteasome pathway O
F
O
Oxidave phosphorylaon
O N+
O CI
N H OH
N H O
O–
O
Niclosamide
O H O
N H O
S
O
N H
F
O
F F
Emricasan
H N
CI
H N
Protein degradaon
N
PHA-690509 CASP1/3/7
CDKs
Nucleus
Regulang cell-cycle transion
Figure 1. Potential Mechanisms of[4_TD$IF] Zika Virus [5_TD$IF](ZIKV[6_TD$IF]) Inhibition by Select Pharmaceuticals. Five pathways potentially involved in [7_TD$IF]ZIKV[3_TD$IF] replication and their inhibition by pharmacological agents with anti-ZIKV activity are illustrated: (i) biosynthesis (guanosine nucleotide synthesis) by mycophenolic acid, (ii) oxidative phosphorylation by niclosamide, (ii) cell-cycle progression by cyclin-dependent kinase inhibitors (PHA-690509), (iv) protein degradation by pan-caspase inhibitors (emricasan), and (v) pro-apoptotic pathways by proteasome inhibitors (bortezomib). Abbreviations: CASP1/3/7, caspase-1/caspase-3/caspase-7; CDKs, cyclindependent kinases; IMPDH, inosine-[8_TD$IF]50 -monophosphate dehydrogenase; NAD+, oxidized nicotinamide adenine dinucleotide; NADH, reduced nicotinamide adenine dinucleotide.
good safety and pharmacokinetics in vivo, ZIKV infection can severely affect pregnant women and fetuses. Clinical trials of repurposed drugs are essential if treatment is to be contemplated for this high-risk group [7,8]. Further, accurate elucidation of the molecular mechanisms underlying the inhibition of ZIKV infection could focus on particular cellular pathways (Figure 1) and lead to the development of highly effective single or Although FDA-approved drugs and clini- combinatorial antiviral therapies. For cal investigational agents have shown example, the potential hits identified antineoplastic proteasome inhibitor acting by potentially blocking pro-apoptotic pathways in cancer, has been identified as a potential anti-ZIKV agent with an EC50 in the micromolar range. Therefore, querying clinically approved anticancer agents (e.g., tyrosine-kinase inhibitors) with low cytotoxicity may provide unexpected opportunities for treating ZIKV infection.
2
Trends in Molecular Medicine, Month Year, Vol. xx, No. yy
might shed light on the precise cellular genes required for ZIKV infection. Combining drug–target network analysis and functional validation might help to identify new genes or pathways serving important roles in ZIKV infection. Developing new high-throughput, drug-repurposing assays, and leveraging existing functional genomics tools (such as gene-trap insertional mutagenesis, RNA interference, and CRISPR/Cas9 editing) against viral replication pathways, may show great promise in the discovery of effective
TRMOME 1179 No. of Pages 3
therapies against ZIKV and other infectious agents.
5. Sakurai, Y. et al. (2015) Two-pore channels control Ebola virus host cell entry and are drug targets for disease treatment. Science 347, 995–998
*Correspondence: [email protected] (F. Cheng). http://dx.doi.org/10.1016/j.molmed.2016.09.006
1
Center for Complex Networks Research, Northeastern University, Boston, MA 02115, USA 2 Center for Cancer Systems Biology, Dana-Farber Cancer Institute, Boston, [9_TD$IF]MA 02215, USA 3
GeneTAG Technology, Inc., Atlanta, GA 30340, USA Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA 5 Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA 4
6
Research Medicine, VA Tennessee Valley Healthcare System, Nashville, TN 37212, USA
References 1. Tabata, T. et al. (2016) Zika virus targets different primary human placental cells, suggesting two routes for vertical transmission. Cell Host Microbe 20, 155–166 2. Laxminarayan, R. et al. (2016) Achieving global targets for antimicrobial resistance. Science 353, 874–875
6. Cheng, F. et al. (2016) Systems biology-based investigation of cellular antiviral drug targets identified by gene-trap insertional mutagenesis. PLoS Comput. Biol. 12, e1005074 7. Barrows, N.J. et al. (2016) A screen of FDA-approved drugs for inhibitors of Zika virus infection. Cell Host Microbe 20, 259–270
3. Nosengo, N. (2016) Can you teach old drugs new tricks? Nature 534, 314–316
8. Xu, M. et al. (2016) Identification of small-molecule inhibitors of Zika virus infection and induced neural cell death via a drug repurposing screen. Nat. Med. Published online August 29, 2016. http://dx.doi.org/10.1038/nm.4184
4. He, S. et al. (2015) Repurposing of the antihistamine chlorcyclizine and related compounds for treatment of hepatitis C virus infection. Sci. Transl. Med. 7, 282ra249
9. Satoh, K. et al. (2016) Identification of niclosamide as a novel anticancer agent for adrenocortical carcinoma. Clin. Cancer Res. 22, 3458–3466
Trends in Molecular Medicine, Month Year, Vol. xx, No. yy
3
Spotlight
Drug Repurposing: New Treatments for Zika Virus Infection? 1,2,
Feixiong Cheng, * James L. Murray,3 and Donald H. Rubin4,5,6 To date, no antiviral agents have been approved for treating Zika virus (ZIKV) infection. Two recent drug-repurposing studies published in Cell Host & Microbe and Nature Medicine demonstrated that screening FDA-approved drugs for antiviral activity is a promising strategy for identifying therapeutics with novel activity against ZIKV infection. Zika virus (ZIKV), a mosquito-borne flavivirus, is associated with severe birth defects and Guillain–Barré syndrome [1]. It is estimated that 1.5 million people have been infected by ZIKV in Brazil after a large outbreak in late 2014, with more than 3500 cases of microcephaly being reported between October 2015 and January 2016 [1]. As of August 24, 2016, 2517 cases had been reported in the United States, including 22 sexually transmitted cases (www.cdc.gov/zika/geo/ united-states.html). In February of 2016, the World Health Organization declared the ZIKV pandemic a Public Health Emergency of International Concern. However, there are no approved therapies to prevent and treat ZIKV infection. Traditional antiviral drug-discovery pipelines involve complex, expensive, and time-consuming processes. The efficacy of pharmaceutical agents targeting viral proteins may be limited because of the emergence of resistant viruses and the potential for untoward side effects [2]. The prospect of drug repurposing, in other words finding new indications for existing
FDA-approved drugs, is emerging as a promising alternative to expedite drug development for infectious diseases [3]. Drug repurposing is especially important for combating rapidly spreading infectious diseases, such as hepatitis C virus [4] and Ebola virus [5,6]. Thus, the systematic screening of FDA-approved drugs may reveal novel agents for treating ZIKV infection [7,8].
one of three different ZIKV strains: PRVABC59 (2015 Puerto STRAIN), FSS13025 (2010 Cambodian strain), and MR766 (1947 Ugandan strain). Using expression of ZIKV protein NS1 as a read-out, Xu et al. further found that two compounds (niclosamide and PHA690509) substantially suppressed ZIKV infection in SNB-19 cells. PHA-690509, a cyclin-dependent kinase inhibitor (CDKi), is under investigation for antiviral activity against diverse viruses [8]. Based on these observations, they identified nine additional hits that suppressed ZIKV infection in SNB-19 cells by examining 27 chemical structurally diverse CDKis. Finally, they further showed that combining treatment with emricasan and PHA-690509 showed similar anti-ZIKV activity compared to either agent alone. However, treatment of PRVABC59-infected hNPCs with emricasan for 72 h followed by niclosamide treatment for 48 h led to ZIKV-negative hNPCs. This suggested that greater ZIKV inhibition might be possible with a treatment combination of emricasan and niclosamide.
Barrows and colleagues [7] screened a library of 774 FDA-approved drugs for efficacy in blocking infection of human HuH-7 hepatocyte cells by a newly isolated ZIKV strain (ZIKV MEX_I_7). They identified 24 potential drugs with validated anti-ZIKV activities, such as ivermectin, mycophenolic acid (MPA), and daptomycin [7]. Specifically, MPA and daptomycin showed particularly high anti-ZIKV activity, with half-maximal effective concentrations (EC50) ranging from 0.1 to 1.0 mM. They further demonstrated that some of these drugs could inhibit ZIKV infection in multiple human cell types, including human cervical, placental, and neural stem cell lines, indicating stable activity against ZIKV. However, the authors did not identify the mechanism-of-action (MoA) for the In summary, the systematic screening of anti-ZIKV activities, in contrast to a previ- FDA-approved drugs highlights emerging avenues for treating ZIKV infection. Howous drug-repurposing study [5]. ever, the MoAs of the identified hits were Xu et al. systematically screened over not explored in either study [7,8]. An inte6000 compounds using a high-through- grated, systems biology-based approach put screening approach that quantified that incorporates drug–target networks, caspase-3 activity and cell viability in virus–host interactomes, and drug microhuman neural progenitor cells (hNPCs) array data may serve as an alternative infected with a prototypic ZIKV strain, approach for identifying anti-ZIKV MoAs MR766 [8]. These compounds included [6]. As shown in Figure 1, recently identi2816 FDA-approved drugs, 2000 drugs fied [6] crosstalk pathways (e.g., pro-apoin clinical trials, and 1280 pharmacologi- ptotic and cell-cycle pathways) between cally active compounds. The authors iden- cancer and viral replication may explain tified over 100 compounds that inhibited why cancer drugs (bortezomib, sorafenib, ZIKV-induced caspase-3 activity in SNB- and niclosamide) often show anti-ZIKV 19 cells. Emricasan, a pan-caspase inhib- activity. For example, niclosamide, an itor, was the most potent anti-ZIKV drug, FDA-approved drug for treating cestode with half-maximal inhibitory concentra- infections in both humans and domestic tions ranging from 0.13 to 0.19 mM in both livestock, has shown broad-spectrum activity potentially via caspase-activity and cell-viability assays. anticancer These experiments were conducted in inhibition of oxidative phosphorylation SNB-19 glioblastoma cells infected with [9]. In addition, bortezomib, an
Trends in Molecular Medicine, Month Year, Vol. xx, No. yy
1
TRMOME 1179 No. of Pages 3
OH HO
Biosynthesis: Guanosine nucleode synthesis
Cytoplasm
O O
O
O
N
O
Mycophenolic acid
NADH
OH B OH
H N
N H
O
N
Bortezomib
NAD+
IMPDH Mitochondria
Inhibitors of Zika Virus (ZIKV)
Pro-apoptoc pathway
Proteasome pathway O
F
O
Oxidave phosphorylaon
O N+
O CI
N H OH
N H O
O–
O
Niclosamide
O H O
N H O
S
O
N H
F
O
F F
Emricasan
H N
CI
H N
Protein degradaon
N
PHA-690509 CASP1/3/7
CDKs
Nucleus
Regulang cell-cycle transion
Figure 1. Potential Mechanisms of[4_TD$IF] Zika Virus [5_TD$IF](ZIKV[6_TD$IF]) Inhibition by Select Pharmaceuticals. Five pathways potentially involved in [7_TD$IF]ZIKV[3_TD$IF] replication and their inhibition by pharmacological agents with anti-ZIKV activity are illustrated: (i) biosynthesis (guanosine nucleotide synthesis) by mycophenolic acid, (ii) oxidative phosphorylation by niclosamide, (ii) cell-cycle progression by cyclin-dependent kinase inhibitors (PHA-690509), (iv) protein degradation by pan-caspase inhibitors (emricasan), and (v) pro-apoptotic pathways by proteasome inhibitors (bortezomib). Abbreviations: CASP1/3/7, caspase-1/caspase-3/caspase-7; CDKs, cyclindependent kinases; IMPDH, inosine-[8_TD$IF]50 -monophosphate dehydrogenase; NAD+, oxidized nicotinamide adenine dinucleotide; NADH, reduced nicotinamide adenine dinucleotide.
good safety and pharmacokinetics in vivo, ZIKV infection can severely affect pregnant women and fetuses. Clinical trials of repurposed drugs are essential if treatment is to be contemplated for this high-risk group [7,8]. Further, accurate elucidation of the molecular mechanisms underlying the inhibition of ZIKV infection could focus on particular cellular pathways (Figure 1) and lead to the development of highly effective single or Although FDA-approved drugs and clini- combinatorial antiviral therapies. For cal investigational agents have shown example, the potential hits identified antineoplastic proteasome inhibitor acting by potentially blocking pro-apoptotic pathways in cancer, has been identified as a potential anti-ZIKV agent with an EC50 in the micromolar range. Therefore, querying clinically approved anticancer agents (e.g., tyrosine-kinase inhibitors) with low cytotoxicity may provide unexpected opportunities for treating ZIKV infection.
2
Trends in Molecular Medicine, Month Year, Vol. xx, No. yy
might shed light on the precise cellular genes required for ZIKV infection. Combining drug–target network analysis and functional validation might help to identify new genes or pathways serving important roles in ZIKV infection. Developing new high-throughput, drug-repurposing assays, and leveraging existing functional genomics tools (such as gene-trap insertional mutagenesis, RNA interference, and CRISPR/Cas9 editing) against viral replication pathways, may show great promise in the discovery of effective
TRMOME 1179 No. of Pages 3
therapies against ZIKV and other infectious agents.
5. Sakurai, Y. et al. (2015) Two-pore channels control Ebola virus host cell entry and are drug targets for disease treatment. Science 347, 995–998
*Correspondence: [email protected] (F. Cheng). http://dx.doi.org/10.1016/j.molmed.2016.09.006
1
Center for Complex Networks Research, Northeastern University, Boston, MA 02115, USA 2 Center for Cancer Systems Biology, Dana-Farber Cancer Institute, Boston, [9_TD$IF]MA 02215, USA 3
GeneTAG Technology, Inc., Atlanta, GA 30340, USA Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA 5 Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA 4
6
Research Medicine, VA Tennessee Valley Healthcare System, Nashville, TN 37212, USA
References 1. Tabata, T. et al. (2016) Zika virus targets different primary human placental cells, suggesting two routes for vertical transmission. Cell Host Microbe 20, 155–166 2. Laxminarayan, R. et al. (2016) Achieving global targets for antimicrobial resistance. Science 353, 874–875
6. Cheng, F. et al. (2016) Systems biology-based investigation of cellular antiviral drug targets identified by gene-trap insertional mutagenesis. PLoS Comput. Biol. 12, e1005074 7. Barrows, N.J. et al. (2016) A screen of FDA-approved drugs for inhibitors of Zika virus infection. Cell Host Microbe 20, 259–270
3. Nosengo, N. (2016) Can you teach old drugs new tricks? Nature 534, 314–316
8. Xu, M. et al. (2016) Identification of small-molecule inhibitors of Zika virus infection and induced neural cell death via a drug repurposing screen. Nat. Med. Published online August 29, 2016. http://dx.doi.org/10.1038/nm.4184
4. He, S. et al. (2015) Repurposing of the antihistamine chlorcyclizine and related compounds for treatment of hepatitis C virus infection. Sci. Transl. Med. 7, 282ra249
9. Satoh, K. et al. (2016) Identification of niclosamide as a novel anticancer agent for adrenocortical carcinoma. Clin. Cancer Res. 22, 3458–3466
Trends in Molecular Medicine, Month Year, Vol. xx, No. yy
3