title: Anticancer activity of a combination of cisplatin and fisetin in embryonal carcinoma cells and xenograft tumors.
abstract: Use of chemotherapeutic drug cisplatin is limited because of its toxicity. Therefore, efforts continue for the discovery of novel combination therapies with cisplatin to reduce its effective treatment dose. This study evaluates the potential of fisetin, a flavonoid, to increase cisplatin cytotoxicity in human embryonal carcinoma NT2/D1 cells. Addition of fisetin to cisplatin enhanced cisplatin cytotoxicity in vitro at four times lower dose than that required by cisplatin monotherapy for similar cytotoxic effects. Cisplatin, fisetin monotherapy, and addition of fisetin to cisplatin in a combination increased FasL expression. Cisplatin and fisetin as single agents activated caspases-8 and -3 and caspases-9 and -7, respectively, whereas combination treatment activated all 4 caspases. Increases in p53 and p21 and decreases in cyclin B1 and survivin occurred, all effects being more exaggerated with the combination. Fisetin, with or without cisplatin, increased expression of proapoptotic protein Bak and induced its mitochondrial oligomerization. Bid truncation and mitochondrial translocation of Bid and p53 was induced by fisetin in the presence or absence of cisplatin. Downregulation of p53 by short hairpin RNA during drug treatment decreased p21 levels but caused survivin increase, thus reducing cell death. Upstream to p53, inhibition of p38 phosphorylation reduced p53 phosphorylation and cell death. In a NT2/D1 mouse xenograft model, combination therapy was most effective in reducing tumor size. In summary, findings of this study suggest that addition of fisetin to cisplatin activates both the mitochondrial and the cell death receptor pathway and could be a promising regimen for the elimination of embryonal carcinoma cells.
authors.affiliation: Cell Death and Differentiation Research Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India.
authors.forename: Rakshamani
authors.initials: R
authors.lastname: Tripathi
authors.forename: Tanmoy
authors.initials: T
authors.lastname: Samadder
authors.forename: Sarika
authors.initials: S
authors.lastname: Gupta
authors.forename: Avadhesha
authors.initials: A
authors.lastname: Surolia
authors.forename: Chandrima
authors.initials: C
authors.lastname: Shaha
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000737:chemistry / Q000494:pharmacology*; D004357:Drug Synergism; D054278:Embryonal Carcinoma Stem Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D005419:Flavonoids / Q000737:chemistry / Q000494:pharmacology*; D044948:Flavonols; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D008928:Mitochondria / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D005419:Flavonoids; D044948:Flavonols; D034741:RNA, Small Interfering; D016159:Tumor Suppressor Protein p53; D048051:p38 Mitogen-Activated Protein Kinases; D020169:Caspases; C017875:fisetin; D002945:Cisplatin