title: Doxycycline induces caspase-dependent apoptosis in human pancreatic cancer cells.
abstract: Doxycycline (DC) belongs to the tetracycline family of antibiotics and has been used clinically for over 5 decades. Despite advances in understanding the molecular pathogenesis of pancreatic cancer, no chemotherapy course has shown significant effectiveness. Hence new treatments are needed. In this study we report the pro-apoptotic effects of DC in 2 pancreatic adenocarcinoma cell lines, T3M4 and GER. Cell proliferation was measured using the SRB protein dye. Induction of apoptosis was detected using ELISA. Caspase activation was detected using either immunoblotting or a colorimetric assay based on cleavage of caspase-associated substrates. Expression of proteins and post-translational modifications were determined using immunoblotting. Treatment of pancreatic cancer cells with DC reduces their proliferation. This reduction is, at least partly, due to increased caspase-dependent apoptosis involving activation of caspase3, caspase7, caspase8, caspase9, caspase10 and increased levels of FADD. Inhibition of caspase8 or caspase10 but not caspase9 significantly decreases DC-induced apoptosis in both cell lines. Furthermore treatment of pancreatic cancer cells with DC increases protein levels of Bax and phosphorylation of members of the p38MAPK pathway such as p38MAPK, MKK3/6 and MAPKAPK2. These results provide an insight into mechanisms behind the pro-apoptotic effects of DC in pancreatic cancer cells.
authors.affiliation: Division of Oncology, Department of Cellular and Molecular Medicine, St. George's University of London, London, United Kingdom.
authors.forename: Petros X E
authors.initials: PX
authors.lastname: Mouratidis
authors.forename: Kay W
authors.initials: KW
authors.lastname: Colston
authors.forename: Angus G
authors.initials: AG
authors.lastname: Dalgleish
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism*; D049109:Cell Proliferation / Q000187:drug effects; D004318:Doxycycline / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D053200:Fas-Associated Death Domain Protein / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D020928:Mitogen-Activated Protein Kinases; D010190:Pancreatic Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D010766:Phosphorylation / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D061945:Caspase Inhibitors; D053200:Fas-Associated Death Domain Protein; D019253:Proto-Oncogene Proteins c-bcl-2; D020928:Mitogen-Activated Protein Kinases; D020169:Caspases; D004318:Doxycycline