title: Gemcitabine and mitomycin induced autophagy regulates cancer stem cell pool in urothelial carcinoma cells.
abstract: Urothelial carcinoma (UC) is characterized by therapeutic resistance and frequent tumor relapse. It has been suggested that UC are driven by a rare subset of cancer stem cells (CSCs). In order to understand UC recurrence post therapy, we investigated the behavior of urothelial CSCs after exposure to commonly used chemotherapeutic agents, gemcitabine (GC) and mitomycin (MM). Although, the role of autophagy in CSC maintenance is well documented, the relationship of autophagy and CSCs with respect to drug resistance remains elusive. In the present study, we found that both GC and MM increased the percentage of CSCs in primary cultured urothelial carcinoma cells (UCC). These CSCs exhibited higher autophagy flux and higher expression of glycolytic genes. Inhibition of autophagy led to decrease in the expression of glycolysis genes. Inhibition of autophagy and glycolysis caused decrease in expression of stemness genes (Oct-4, Nanog), drug resistance genes (ABCG2, MDR1) and sensitized CSCs to GC and MM induced apoptosis. This finding suggests that autophagy and glycolysis may play a central role in drug resistance. Altogether, we conclude that autophagy may support cell survival by buffering bioenergetic demands for maintenance of high glycolytic flux in CSCs. Therefore, autophagy-based, "customized" combinatorial approaches may provide a new method to counter CSC-driven resistance and may prevent relapse in UC. The synergistic cytotoxic effect of GC/ MM with autophagy inhibitor (chloroquine) or with glycolytic inhibitor (2-deoxyglucose) may be of help in improving the outcome in patients with urothelial carcinoma of urinary bladder.
authors.affiliation: Department of Urology, Post Graduate Institute of Medical Education and Research, Chandigarh 160012, India.
authors.forename: Rani
authors.initials: R
authors.lastname: Ojha
authors.affiliation: Department of Nephrology, Post Graduate Institute of Medical Education and Research, Chandigarh 160012, India.
authors.forename: V
authors.initials: V
authors.lastname: Jha
authors.affiliation: Department of Urology, Post Graduate Institute of Medical Education and Research, Chandigarh 160012, India. Electronic address: shrawanksingh2002@yahoo.com.
authors.forename: S K
authors.initials: SK
authors.lastname: Singh
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000494:pharmacology; D001343:Autophagy / Q000187:drug effects* / Q000235:genetics; D000071193:Autophagy-Related Protein 7; D015153:Blotting, Western; D002295:Carcinoma, Transitional Cell / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D005260:Female; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006019:Glycolysis / Q000187:drug effects / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D016685:Mitomycin / Q000494:pharmacology*; D014411:Neoplastic Stem Cells / Q000187:drug effects* / Q000378:metabolism; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D044764:Ubiquitin-Activating Enzymes / Q000235:genetics / Q000378:metabolism; D001749:Urinary Bladder Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D055815:Young Adult; D000093542:Gemcitabine
chemical_list: D000970:Antineoplastic Agents; D003841:Deoxycytidine; D016685:Mitomycin; C509349:ATG7 protein, human; D000071193:Autophagy-Related Protein 7; D044764:Ubiquitin-Activating Enzymes; D000093542:Gemcitabine
keywords: Apoptosis; Autophagy; Cancer stem cells; Chemotherapy; Glycolysis; Urothelial carcinoma