title: ADAM17 mediates hypoxia-induced drug resistance in hepatocellular carcinoma cells through activation of EGFR/PI3K/Akt pathway.
abstract: A disintegrin and metalloproteinase-17 (ADAM17) is a member of the metalloproteinase superfamily and involved in the cleavage of ectodomain of many transmembrane proteins. ADAM17 is overexpressed in a variety of human tumors, which is associated with tumor development and progression. In the present study, we sought to investigate the expression and function of ADAM17 in hypoxia-treated hepatocellular carcinoma (HCC) cells. Western blot analysis was used to measure the expression of ADAM17 in HCC cell lines (Hep3B and HepG2 cells). Annexin V/PI double staining was performed to analyze the effects of ADAM17 on hypoxia-mediated cisplatin resistance. ADAM17 expression was upregulated by hypoxia treatment in HCC cells at both mRNA and protein levels. Overexpression of ADAM17 reduced cisplatin-induced apoptosis in HCC cells, accompanies by less cleavage of caspase-3 and poly (ADP-ribose) polymerase (PARP). Forced expression of ADAM17 enhanced the phosphorylation of epidermal growth factor receptor (EGFR) and Akt without affecting the expression of total EGFR and Akt. Pretreatment with EGFR inhibitor AG1478 or phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 rescued ADAM17-mediated cisplatin resistance of HCC cells. ADAM17 silencing attenuated hypoxia-induced cisplatin resistance and enhanced the accumulation of cleaved caspase-3 and PARP. Western blot analysis showed that overexpression of hypoxia-inducible factor-1α (HIF-1α), a transcription factor, upregulated the expression of ADAM17 and HIF-1α silencing downregulated the expression of ADAM17 in hypoxia-treated HCC cells, indicating the regulation of ADAM17 by HIF-1α. Taken together, our results indicated that ADAM17 is upregulated by hypoxia and contributes to hypoxia-induced cisplatin resistance via EGFR/PI3K/Akt pathway.
authors.affiliation: Department of Pharmacy, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou 450014, China. bioxiangjunwang@163.com
authors.forename: Xiang-Jun
authors.initials: XJ
authors.lastname: Wang
authors.forename: Chang-Wei
authors.initials: CW
authors.lastname: Feng
authors.forename: Min
authors.initials: M
authors.lastname: Li
mesh_terms: D051722:ADAM Proteins / Q000235:genetics / Q000378:metabolism*; D000072198:ADAM17 Protein; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000235:genetics; D066246:ErbB Receptors / Q000378:metabolism*; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors
chemical_list: D000970:Antineoplastic Agents; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D019869:Phosphatidylinositol 3-Kinases; C512478:EGFR protein, human; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human; D002945:Cisplatin