title: Bafilomycin A1 induces caspase-independent cell death in hepatocellular carcinoma cells via targeting of autophagy and MAPK pathways.
abstract: Hepatocellular carcinoma (HCC) is refractory to chemotherapies, necessitating novel effective agents. The lysosome inhibitor Bafilomycin A1 (BafA1) at high concentrations displays cytotoxicity in a variety of cancers. Here we show that BafA1 at nanomolar concentrations suppresses HCC cell growth in both 2 dimensional (2D) and 3D cultures. BafA1 induced cell cycle arrest in the G1 phase and triggered Cyclin D1 turnover in HCC cells in a dual-specificity tyrosine phosphorylation-regulated kinase 1B (DYRK1B) dependent manner. Notably, BafA1 induced caspase-independent cell death in HCC cells by impairing autophagy flux as demonstrated by elevated LC3 conversion and p62/SQSTM1 levels. Moreover, genetic ablation of LC3 significantly attenuated BafA1-induced cytotoxicity of HCC cells. We further demonstrate that pharmacological down-regulation or genetic depletion of p38 MAPK decreased BafA1-induced cell death via abolishment of BafA1-induced upregulation of Puma. Notably, knockdown of Puma impaired BafA1-induced HCC cell death, and overexpression of Puma enhanced BafA1-mediated HCC cell death, suggesting a role for Puma in BafA1-mediated cytotoxicity. Interestingly, pharmacological inhibition of JNK with SP600125 enhanced BafA1-mediated cytotoxicity both in vitro and in xenografts derived from HCC cells. Taken together, our data suggest that BafA1 may offer potential as an effective therapy for HCC.
authors.affiliation: Department of Hepatobiliary Surgery, the First Affiliated Hospital, Dalian Medical University, No. 222 Zhongshan Road, Dalian 116021, China.|The First Department of Ultrasound, the First Affiliated Hospital to Dalian Medical University, No. 222 Zhongshan Road, Dalian 116021, China.|Dalian Key Laboratory of Hepatobiliary Pancreatic Diseases Prevention and Treatment, Dalian 116021, China.|Dalian Medical University Graduate School, 9 Lvshun Road South, Dalian 116044, China.
authors.forename: Yumei
authors.initials: Y
authors.lastname: Yan
authors.affiliation: Institute of Cancer Stem Cell, Dalian Medical University Cancer Center, 9 Lvshun Road South, Dalian 116044, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Jiang
authors.affiliation: Department of Hepatobiliary Surgery, the First Affiliated Hospital, Dalian Medical University, No. 222 Zhongshan Road, Dalian 116021, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Liu
authors.affiliation: Department of Hepatobiliary Surgery, the First Affiliated Hospital, Dalian Medical University, No. 222 Zhongshan Road, Dalian 116021, China.
authors.forename: Xianbin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Hepatobiliary Surgery, the First Affiliated Hospital, Dalian Medical University, No. 222 Zhongshan Road, Dalian 116021, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Dong
authors.affiliation: Department of Hepatobiliary Surgery, the First Affiliated Hospital, Dalian Medical University, No. 222 Zhongshan Road, Dalian 116021, China.
authors.forename: Jingchun
authors.initials: J
authors.lastname: Gao
authors.affiliation: Institute of Cancer Stem Cell, Dalian Medical University Cancer Center, 9 Lvshun Road South, Dalian 116044, China.
authors.forename: Quentin
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Thoracic Oncology Research Group, Trinity Translational Medicine Institute, Trinity Centre for Health Sciences, St. James's Hospital &Trinity College, Dublin, Ireland.
authors.forename: Martin P
authors.initials: MP
authors.lastname: Barr
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, China.
authors.forename: Quan
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: The First Department of Ultrasound, the First Affiliated Hospital to Dalian Medical University, No. 222 Zhongshan Road, Dalian 116021, China.
authors.forename: Xiukun
authors.initials: X
authors.lastname: Hou
authors.affiliation: Institute of Cancer Stem Cell, Dalian Medical University Cancer Center, 9 Lvshun Road South, Dalian 116044, China.
authors.forename: Songshu
authors.initials: S
authors.lastname: Meng
authors.affiliation: Department of Hepatobiliary Surgery, the First Affiliated Hospital, Dalian Medical University, No. 222 Zhongshan Road, Dalian 116021, China.|Dalian Key Laboratory of Hepatobiliary Pancreatic Diseases Prevention and Treatment, Dalian 116021, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Gong
mesh_terms: D000818:Animals; D001343:Autophagy / Q000187:drug effects* / Q000235:genetics; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D020169:Caspases / Q000235:genetics / Q000378:metabolism; D005260:Female; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D020935:MAP Kinase Signaling System / Q000187:drug effects* / Q000235:genetics; D018942:Macrolides / Q000494:pharmacology*; D051379:Mice; D008819:Mice, Nude; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
chemical_list: D018942:Macrolides; D009363:Neoplasm Proteins; C040929:bafilomycin A1; D020169:Caspases