Replication-defective adenovirus in combination with Dacarbazine results in enhanced melanoma cells apoptosis

Objective To observe the effects of the combined use of replication-defective adenovirus carrying mda-7 ( Ad-mda-7) with Dacarbazine (DTIC) on the apoptosis of a melanoma cell line Ml4.Methods M14 cells were divided into 4 groups; PBS group, DTIC group, Ad-mda-7 group, Ad-mda-7 plus DTIC group. The inhibitory rate of cells was assessed by CCK-8 assay. Cell cytotoxic effect and apoptosis were determined by crystal violet staining method and Annexin V asssy, respectively. Furthermore, mda-7 proteins, bax, Mcl-1, bcl-xL, Caspase-9 and Caspase-3 apoptosis related proteins were determined by Western blotting. Results CCK-8 assay revealed the inhibitory rate after 48 h in the Ad-mda-7 (10 MOI) plus DTIC (10 mg/L) group (73.56 ±2.58)% was significantly higher than Ad-mda-7 group (33.30 ± 3.38 ) % and DTIC group (15.75 ± 3.21) % ( P < 0.05). Crystal violet staining method showed Ad-mda-7 plus DTIC could induce more significant cytotoxiciy to M14 cells than Ad-mda-7 group or DTIC group. Annexin V assay indicated that the apoptosis rate after 48 h in Ad-mda-7 + DTIC group (71.47 ± 3.57)% was significantly higher than in Ad-mda-7 group (40.11 ±3.61)% and DTIC group (23.27 ± 2.30)% (P<0.05). Western blotting analysis confirmed that M14 cells treated with Ad-mda-7 plus DTIC could express mda-7 with high efficiency, and simultaneously, the bax expression was increased, the expression of Mcl-1 and bcl-xL reduced and Caspase-9 and Caspase-3 were acitivated. Conclusion Ad-mda-7 in combination with DTIC exhibited a remarkably increased apoptosis-inducing effects in melanoma cells. Key words: Adenovirus vector;  mda-7;  DTIC;  Melanoma