HIF1/2α mediates hypoxia-induced LDHA expression in human pancreatic cancer cells

Abstract

// Xin-gang Cui 2, * , Zhi-tao Han 1, 6, * , Shao-hui He 1, * , Xing-da Wu 3, * , Tian-rui Chen 1 , Cheng-hao Shao 4 , Dan-lei Chen 4 , Ning Su 5 , Yuan-ming Chen 6 , Ting Wang 1 , Jing Wang 1 , Dian-Wen Song 1 , Wang-jun Yan 1 , Xing-Hai Yang 1 , Tielong Liu 1 , Hai-feng Wei 1 , Jianru Xiao 1 1 Department of Bone Tumor Surgery, Changzheng Hospital, Second Military Medical University, Shanghai, China 2 Department of Urinary Surgery of Third Affiliated Hospital, Second Military Medical University, Shanghai, China 3 Department of Pancreatic Surgery, the First Hospital of China Medical University, Shenyang, China 4 Department of Pancreatic Surgery, Changzheng Hospital, the Second Military Medical University, Shanghai, China 5 Department of Colorectal Surgery, Changzheng Hospital, Second Military Medical University, Shanghai, China 6 Department of Spine Surgery, Ruikang Hospital, Guangxi University Of Chinese Medicine, Guangxi, China * Xin-gang Cui, Zhi-tao Han, Shao-hui He, Xing-da Wu contributed equally to this work Correspondence to: Jianru Xiao, email: jianruxiao83@163.com Tielong Liu, email: czyyltl@163.com Hai-feng Wei, email: weihfspine@163.com Keywords: HIF-1, HIF-2, hypoxia, LDHA, pancreatic cancer Received: December 30, 2015     Accepted: December 15, 2016     Published: February 10, 2017 ABSTRACT Glycolysis is a typical conduit for energy metabolism in pancreatic cancer (PC) due to the hypoxic microenviroment. Lactate dehydrogenase A (LDHA) catalyzes the conversion of pyruvate to lactate and is considered to be a key checkpoint of anaerobic glycolysis. The aim of the present study was to explore the mechanism of interactions between hypoxia, HIF-1/2α and LDHA, and the function of LDHA on PC cells by analyzing 244 PC and paratumor specimens. It was found that LDHA was over-expressed and related to tumor stages. The result of in vitro study demonstrated that hypoxia induced LDHA expression. To explore the relationship between HIF and LDHA, chromatin immunoprecipitation assay and luciferase assay were performed. The result showed that HIF-1/2α bound to LDHA at 89bp under the hypoxic condition. Furthermore, knockdown of endogenous HIF-1α and HIF-2α decreased the LDHA expression even in the hypoxic condition, which was accompanied with a significant decrease in lactate production and glucose utilization (p < 0.01). Immunofluorescence in the 244 specimens showed that HIF-1/2α was over-expressed and associated with LDHA over-expression (p < 0.0001). Forced expression of LDHA promoted the growth and migration of PC cells, while knocking down the expression of LDHA inhibited the cell growth and migration markedly. In summary, the present study proved that HIF1/2α could activate LDHA expression in human PC cells, and high expression of LDHA promoted the growth and migration of PC cells.