title: AMPK-autophagy inhibition sensitizes icaritin-induced anti-colorectal cancer cell activity.
abstract: The current research studied the potential effect of autophagy on icaritin-induced anti-colorectal cancer (CRC) cell activity. Treatment of icaritin in both primary and established (HT-29) CRC cells induced feedback activation of autophagy, evidenced by p62 degradation, Beclin-1 and autophagy-related gene-5 (ATG-5) upregulation, as well as light chain 3B (LC3B)-GFP puncta formation. Pharmacological inhibiting of autophagy dramatically potentiated icaritin-induced CRC cell death and apoptosis. Meanwhile, shRNA-mediated knockdown of Beclin-1 or ATG-5 also sensitized icaritin-induced CRC cell death and apoptosis. Icaritin activated AMP-activated protein kinase (AMPK) signaling in CRC cells, functioning as the upstream signaling for autophagy activation. shRNA/siRNA-mediated knockdown of AMPKα1inhibited icaritin-induced autophagy activation, but exacerbated CRC cell death. On the other hand, the AMPK activator compound 13 (C13) or the autophagy activator MHY1485 attenuated icaritin-induced cytotoxicity. In nude mice, icaritin (oral administration)-induced HT-29 tumor growth inhibition was potentiated when combined with AMPKα1 shRNA knockdown in tumors. We conclude that feedback activation of AMPK-autophagy pathway could be a primary resistance factor of icaritin.
authors.affiliation: Department of Interventional Radiology, Wujiang Hospital Affiliated to Nantong University, Wujiang, Suzhou, China.
authors.forename: Chunxian
authors.initials: C
authors.lastname: Zhou
authors.affiliation: The Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Suzhou, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Gu
authors.affiliation: Department of Interventional Radiology, Wujiang Hospital Affiliated to Nantong University, Wujiang, Suzhou, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Department of Interventional Radiology, Wujiang Hospital Affiliated to Nantong University, Wujiang, Suzhou, China.
authors.forename: Da
authors.initials: D
authors.lastname: Dong
authors.affiliation: Department of Interventional Radiology, Wujiang Hospital Affiliated to Nantong University, Wujiang, Suzhou, China.
authors.forename: Qunying
authors.initials: Q
authors.lastname: Yang
authors.affiliation: Department of Oncology, Kunshan First People's Hospital Affiliated to Jiangsu University, Kunshan, 215300, China.
authors.forename: Min-Bin
authors.initials: MB
authors.lastname: Chen
authors.affiliation: Department of Interventional Radiology, Wujiang Hospital Affiliated to Nantong University, Wujiang, Suzhou, China.
authors.forename: Dongfeng
authors.initials: D
authors.lastname: Xu
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D001343:Autophagy / Q000187:drug effects* / Q000235:genetics; D000071187:Autophagy-Related Protein 5 / Q000235:genetics / Q000378:metabolism; D000071186:Beclin-1 / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology*; D019073:HT29 Cells; D006801:Humans; D008297:Male; D008819:Mice, Nude; D008875:Middle Aged; D009025:Morpholines / Q000494:pharmacology; D034622:RNA Interference; D015398:Signal Transduction / Q000187:drug effects* / Q000235:genetics; D014227:Triazines / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays / Q000379:methods
chemical_list: C577756:4,6-dimorpholino-N-(4-nitrophenyl)-1,3,5-triazin-2-amine; D000071187:Autophagy-Related Protein 5; D000071186:Beclin-1; D005419:Flavonoids; D009025:Morpholines; D014227:Triazines; D055372:AMP-Activated Protein Kinases; C499403:icaritin
keywords: AMPK; autophagy; chemosensitization; colorectal cancer; icaritin