SIRT1 and AMPK mediate hypoxia-induced resistance of non-small cell lung cancers to cisplatin and doxorubicin.
SIRT1 is an NAD(+)-dependent protein deacetylase induced by metabolic stresses, such as nutrition or oxygen deprivation. Although SIRT1 contributes to aging and metabolic disorders, its role in cancer progression and therapeutic responses remains controversial. Because hypoxia occurs widely in solid tumors, where it provokes drug resistance, we investigated the involvement of SIRT1 in hypoxia-induced chemoresistance. SIRT1 was downregulated in a panel of non-small cell lung carcinoma (NSCLC) cells exposed to hypoxia for 48 hours. The master metabolic kinase AMP-activated protein kinase (AMPK) was inactivated under the same conditions, likely due to attenuation of the SIRT1/LKB1-mediated AMPK activation process. Notably, hypoxic inactivation of this SIRT1-AMPK pathway led to cisplatin and doxorubicin resistance. Mechanistic investigations suggested that this pathway supported the cytotoxic response to cisplatin and doxorubicin by licensing an apoptotic process controlled by mitochondria. We confirmed the involvement of this pathway in a mouse xenograft model of human NSCLC. Furthermore, we demonstrated that a SIRT1 activator SRT1720 augmented the antitumor effects of cisplatin, and these effects could be blocked by administration of an AMPK inhibitor compound C. Taken together, our results offer preclinical proof-of-concept to target the SIRT1-AMPK pathway as a strategy to overcome hypoxia-induced chemoresistance in NSCLC.
Authors' Affiliation: Departments of Pharmacology and Biomedical Science, Ischemic/Hypoxic Disease Institute, Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea.
Dong Hoon
DH
Shin
Yong-Joon
YJ
Choi
Jong-Wan
JW
Park
D055372:AMP-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D015687:Cell Hypoxia / Q000502:physiology*; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology*; D004317:Doxorubicin / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008819:Mice, Nude; D015398:Signal Transduction; D056564:Sirtuin 1 / Q000235:genetics / Q000378:metabolism*; D023041:Xenograft Model Antitumor Assays
D004317:Doxorubicin; D055372:AMP-Activated Protein Kinases; C447939:SIRT1 protein, human; D056564:Sirtuin 1; D002945:Cisplatin