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Heat Shock Proteins and Cytoskeleton Hypothesis in Proteasome Inhibitors-Induced Peripheral Neuropathy
growth inhibition was more significant in shNRF2-HT29 group. Collectively, these results showed that NRF2 suppression in cancer cells altered mitochondrial function, which results in AMPK activation to generate energy for cancer cell survival.
doi: xxxxx doi: 10.1016/j.freeradbiomed.2015.10.176
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Andrew Little1, Aida Habibovic1, Milena Hristova1, and Albert van der Vliet1 1 University of Vermont, USA
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Betul Karademir1, Gulce Sari1, Sravani Musuruni2, Grzegorz Wicher2, Tobias Jung3, Jia Mi2, Jonas Bergquist2, and Tilman Grune3 1 Marmara University, Istanbul, Turkey, 2Uppsala University, Uppsala, Sweden, 3German Institute of Human Nutrition, Potsdam-Rehbruecke (DIfE), Germany Proteasome inhibitors are promising chemotherapeutic agents due to different levels and activities of proteasome components in cancer and normal cells. Bortezomib as a proteasome inhibitor is widely used in the clinic over 15 years in addition to classical chemotherapy and radiotherapy. Many studies have also shown that it is a crucial agent to overcome the drug resistance which is a main problem in treatment process. However, peripheral neuropathy as the main toxic side effect of this inhibitor is the main reason for dose limitations. In this point, second generation proteasome inhibitors have been developed to decrease this side effect and carfilzomib is the mostly used one. The less toxic effect of carfilzomib has been speculated as boron moiety of bortezomib affects the non-proteasomal targets whereas epoxyketone moiety of carfilzomib does not. However related mechanisms are still unknown and therefore futher studies are required. In this study, we aimed to compare the differences between bortezomib and carfilzomib treated cells regarding the mechanisms of peripheral neuropathy. In this direction, we isolated neural stem cells from embryonic mouse cortex and treated with bortezomib and carfilzomib. First of all, we tested proteasome inhibition following treatment of cells with inhibitors for 3h and 24h. Afterwards, proteomic analysis was performed by nanoLC-MS/MS using a 7 T hybrid LTQ-FT mass spectrometer. 3URWHLQ LGHQWL¿FDWLRQ ZDV FDUULHG RXW XVLQJ 0$6&27 VHDUFK engine with a confidence level of 95% and proteins were quantified using MaxQuant software. Obtained data showed significant differences in cytoskeleton related proteins such as transgelin-2, actin related protein-2 and beta tubulin. Furthermore, the levels of heat shock proteins 10, 70 and 90 were found be effected. Different expression patterns of HSPs and also the relation between HSPs and cytoskeleton damage which is thought to be contributing to bortezomib-induced peripheral neuropathy. We conclude that HSPs are important not only for organization of unfolded proteins accumulated after proteasome inhibition, but also for re-stabilization of cytoskeleton against cytoskeletonal damage which provokes chemotherapy (especially bortezomib)induced neuropathy.
doi: xxxxx doi: 10.1016/j.freeradbiomed.2015.10.177
137
Lung cancer is the leading cause of cancer-related mortality in the USA and worldwide, accounting for over 1.5 million deaths per year. Although lung cancer is a heterogeneous disease, nonsmall cell lung cancer (NSCLC) comprises about 80% of lung cancers. Recently, it has been shown that DUOX1, an NADPH oxidase homolog normally expressed within differentiated airway and alveolar epithelia, is significantly reduced in various forms of NSCLC. Our recent studies indicate that RNAi-mediated suppression of DUOX1 in lung epithelial cancer cells induces features of epithelial-to-mesenchymal transition (EMT), and leads to acquired resistance to the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) erlotinib and enhanced cancer stem cell characteristics. Conversely, EMT features could be reversed upon overexpression of DUOX1 into lung cancer cells. In addition, DUOX1 silencing was also found to promote invasive properties of lung cancer cells in vitro and in vivo. Although the mechanism(s) by which DUOX1 silencing promotes EMT, tumor invasiveness and TKI resistance are not understood, previous findings linking epithelial DUOX1 with redox-dependent regulation of epithelial signaling via the non-receptor tyrosine kinase, Src, and the receptor tyrosine kinase, EGFR, would suggest that loss of DUOX1 in lung cancer may be associated with aberrant regulation of Src and/or EGFR, tyrosine kinases that are frequently overexpressed and activated in lung cancer and strongly contribute to tumor growth and survival. Furthermore, nuclear Src/EGFR localization in lung cancers was recently associated with metastatic cell behavior and poor clinical outcome. Preliminary findings in alveolar lung cancer A549 cells indicate that DUOX1 overexpression redistributes Src localization to the plasma membrane and decreases nuclear accumulation. Moreover, DUOX1-overexpressing A549 cells also display suppressed EGFR internalization and nuclear translocation upon EGF stimulation. Collectively, our findings indicate that DUOX1 silencing in lung cancer may contribute to EMT and/or tumor invasiveness by altering Src/EGFR localization and activation mechanisms. Supported by NIH R01HL085646, NIH T32HL076122, and VCC/LCCRO.
doi: xxxxx doi: 10.1016/j.freeradbiomed.2015.10.178 138 $PHOLRUDWLRQRI'LHWK\OQLWURVDPLQH '(1 )HUULF 1LWURORWULDFHWDWH )H17$ 0HGLDWHG5HQDO &DUFLQRJHQHVLVE\'LHWDU\6LO\PDULQ$0HFKDQLVWLF $SSURDFK
Irshad Ahmad Lone1, M Sarwar Alam2, and M Athar2 1 Govt. Degree College Handwara, India, 2Jamia Hamdard, Hamdard Nagar, India Silymarin, a biologically active flavonoid complex, is a potent oxygen free radical scavenger and a metal chelator. Ferric nitrolotriacetate (Fe-NTA) is a potent nephrotoxic agent and a renal carcinogen that mediates its effect by inducing oxidative stress. In the present communication, we document the
S68
SFRBM 2015
doi: xxxxx doi: 10.1016/j.freeradbiomed.2015.10.176
'82;6LOHQFLQJLQ/XQJ&DQFHU,V$VVRFLDWHGZLWK (07$FTXLUHG(UORWLQLE5HVLVWDQFHDQG$OWHUHG /RFDOL]DWLRQDQG$FWLYDWLRQRI6UFDQG(*)5
Andrew Little1, Aida Habibovic1, Milena Hristova1, and Albert van der Vliet1 1 University of Vermont, USA
136 +HDW6KRFN3URWHLQVDQG&\WRVNHOHWRQ+\SRWKHVLVLQ 3URWHDVRPH,QKLELWRUV,QGXFHG3HULSKHUDO 1HXURSDWK\
Betul Karademir1, Gulce Sari1, Sravani Musuruni2, Grzegorz Wicher2, Tobias Jung3, Jia Mi2, Jonas Bergquist2, and Tilman Grune3 1 Marmara University, Istanbul, Turkey, 2Uppsala University, Uppsala, Sweden, 3German Institute of Human Nutrition, Potsdam-Rehbruecke (DIfE), Germany Proteasome inhibitors are promising chemotherapeutic agents due to different levels and activities of proteasome components in cancer and normal cells. Bortezomib as a proteasome inhibitor is widely used in the clinic over 15 years in addition to classical chemotherapy and radiotherapy. Many studies have also shown that it is a crucial agent to overcome the drug resistance which is a main problem in treatment process. However, peripheral neuropathy as the main toxic side effect of this inhibitor is the main reason for dose limitations. In this point, second generation proteasome inhibitors have been developed to decrease this side effect and carfilzomib is the mostly used one. The less toxic effect of carfilzomib has been speculated as boron moiety of bortezomib affects the non-proteasomal targets whereas epoxyketone moiety of carfilzomib does not. However related mechanisms are still unknown and therefore futher studies are required. In this study, we aimed to compare the differences between bortezomib and carfilzomib treated cells regarding the mechanisms of peripheral neuropathy. In this direction, we isolated neural stem cells from embryonic mouse cortex and treated with bortezomib and carfilzomib. First of all, we tested proteasome inhibition following treatment of cells with inhibitors for 3h and 24h. Afterwards, proteomic analysis was performed by nanoLC-MS/MS using a 7 T hybrid LTQ-FT mass spectrometer. 3URWHLQ LGHQWL¿FDWLRQ ZDV FDUULHG RXW XVLQJ 0$6&27 VHDUFK engine with a confidence level of 95% and proteins were quantified using MaxQuant software. Obtained data showed significant differences in cytoskeleton related proteins such as transgelin-2, actin related protein-2 and beta tubulin. Furthermore, the levels of heat shock proteins 10, 70 and 90 were found be effected. Different expression patterns of HSPs and also the relation between HSPs and cytoskeleton damage which is thought to be contributing to bortezomib-induced peripheral neuropathy. We conclude that HSPs are important not only for organization of unfolded proteins accumulated after proteasome inhibition, but also for re-stabilization of cytoskeleton against cytoskeletonal damage which provokes chemotherapy (especially bortezomib)induced neuropathy.
doi: xxxxx doi: 10.1016/j.freeradbiomed.2015.10.177
137
Lung cancer is the leading cause of cancer-related mortality in the USA and worldwide, accounting for over 1.5 million deaths per year. Although lung cancer is a heterogeneous disease, nonsmall cell lung cancer (NSCLC) comprises about 80% of lung cancers. Recently, it has been shown that DUOX1, an NADPH oxidase homolog normally expressed within differentiated airway and alveolar epithelia, is significantly reduced in various forms of NSCLC. Our recent studies indicate that RNAi-mediated suppression of DUOX1 in lung epithelial cancer cells induces features of epithelial-to-mesenchymal transition (EMT), and leads to acquired resistance to the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) erlotinib and enhanced cancer stem cell characteristics. Conversely, EMT features could be reversed upon overexpression of DUOX1 into lung cancer cells. In addition, DUOX1 silencing was also found to promote invasive properties of lung cancer cells in vitro and in vivo. Although the mechanism(s) by which DUOX1 silencing promotes EMT, tumor invasiveness and TKI resistance are not understood, previous findings linking epithelial DUOX1 with redox-dependent regulation of epithelial signaling via the non-receptor tyrosine kinase, Src, and the receptor tyrosine kinase, EGFR, would suggest that loss of DUOX1 in lung cancer may be associated with aberrant regulation of Src and/or EGFR, tyrosine kinases that are frequently overexpressed and activated in lung cancer and strongly contribute to tumor growth and survival. Furthermore, nuclear Src/EGFR localization in lung cancers was recently associated with metastatic cell behavior and poor clinical outcome. Preliminary findings in alveolar lung cancer A549 cells indicate that DUOX1 overexpression redistributes Src localization to the plasma membrane and decreases nuclear accumulation. Moreover, DUOX1-overexpressing A549 cells also display suppressed EGFR internalization and nuclear translocation upon EGF stimulation. Collectively, our findings indicate that DUOX1 silencing in lung cancer may contribute to EMT and/or tumor invasiveness by altering Src/EGFR localization and activation mechanisms. Supported by NIH R01HL085646, NIH T32HL076122, and VCC/LCCRO.
doi: xxxxx doi: 10.1016/j.freeradbiomed.2015.10.178 138 $PHOLRUDWLRQRI'LHWK\OQLWURVDPLQH '(1 )HUULF 1LWURORWULDFHWDWH )H17$ 0HGLDWHG5HQDO &DUFLQRJHQHVLVE\'LHWDU\6LO\PDULQ$0HFKDQLVWLF $SSURDFK
Irshad Ahmad Lone1, M Sarwar Alam2, and M Athar2 1 Govt. Degree College Handwara, India, 2Jamia Hamdard, Hamdard Nagar, India Silymarin, a biologically active flavonoid complex, is a potent oxygen free radical scavenger and a metal chelator. Ferric nitrolotriacetate (Fe-NTA) is a potent nephrotoxic agent and a renal carcinogen that mediates its effect by inducing oxidative stress. In the present communication, we document the
S68
SFRBM 2015