title: Adenovirus-mediated FKHRL1/TM sensitizes melanoma cells to apoptosis induced by temozolomide.
abstract: Melanoma exhibits variable resistance to the alkylating agent temozolomide (TMZ). We evaluated the potential of adenovirus expressing forkhead human transcription factor like 1 triple mutant (Ad-FKHRL1/TM) to sensitize melanoma cells to TMZ. Four melanoma cell lines were treated with Ad-FKHRL1/TM and TMZ, alone or in combination. Apoptosis was assessed by activation and inhibition of caspase pathway, nuclei fragmentation, and annexin V staining. The potential therapeutic efficacy of Ad-FKHRL1/TM with TMZ was also assessed in a mouse melanoma xenograft model. Combination therapy of Ad-FKHRL1/TM and TMZ resulted in greater cell killing (<20% cell viability) compared with single therapy and controls (p<0.05). Combination indices of Ad-FKHRL1/TM and TMZ therapy indicated significant (p<0.05) synergistic killing effect. Greater apoptosis induction was found in cells treated with Ad-FKHRL1/TM and TMZ than with Ad-FKHRL1/TM or TMZ-treated cells alone. Treatment with TMZ enhanced adenovirus transgene expression in a cell type-dependent manner. In an in vivo model, combination therapy of Ad-FKHRL1/TM with TMZ results in greater tumor growth reduction in comparison with single treatments. We suggest that Ad-FKHRL1/TM is a promising vector to sensitize melanoma cells to TMZ, and that a combination of both approaches would be effective in the clinical setting.
authors.affiliation: 1 The Hiram C. Polk Jr., MD, Department of Surgery, University of Louisville School of Medicine , Louisville, KY 40292.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Egger
authors.forename: Lacey R
authors.initials: LR
authors.lastname: McNally
authors.forename: Jonathan
authors.initials: J
authors.lastname: Nitz
authors.forename: Kelly M
authors.initials: KM
authors.lastname: McMasters
authors.forename: Jorge G
authors.initials: JG
authors.lastname: Gomez-Gutierrez
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D003606:Dacarbazine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors / Q000235:genetics* / Q000378:metabolism; D015316:Genetic Therapy; D006801:Humans; D008297:Male; D008545:Melanoma / Q000628:therapy*; D051379:Mice; D008807:Mice, Inbred BALB C; D000077204:Temozolomide; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
chemical_list: C499517:FOXO3 protein, human; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors; D014157:Transcription Factors; D003606:Dacarbazine; D000077204:Temozolomide