Abstract

This study explored Cisplatin resistance effect of microRNA-21 (miR-21) antisense oligonucleotide (AS-ODN) in human melanoma A375 cell. AS-ODN was transfected in melanoma A375 cells and Cisplatin-resistant cell line A375/CDDP, and divided into the AS-ODN, nonsense oligonucleotide (NS-ODN) and normal groups. Cell ultrastructure changes were observed through transmission electron microscope. MiR-21 AS-ODN could be tested cell growth effect in different time periods by trypan blue exclusion. MiR-21 mRNA expression change was detected by quantitative fluorescence PCR. Cell apoptosis, cycle distribution and miR-21 AS-ODN effect on proliferation and Cisplatin sensitivity were tested by flow cytometry, MTT assay, TUNEL, and Clonogenic assay. Cell apoptosis was observed after transfection 24 h with the AS-ODN group, while the NS-ODN and normal group cells had no apoptotic symptoms; Compared with the normal group, the AS-ODN group began to show obvious cell growth inhibition effect after transfection 24 h lasting 72 h (all P < 0.05), but the NS-ODN group had no significant difference ( P > 0.05). miR-21 mRNA expression in the AS-ODN group was obviously decreased with rising apoptosis rate (all P < 0.05) and there was no significant difference in the NS-ODN group ( P > 0.05). MiR-21 AS-ODN could remarkably increase A375 cell and A375/CDDP cell sensitivity to Cisplatin ( P < 0.05), while A375 cell sensitivity to Cisplatin between the NS-ODN group and the normal group had no difference. MiR-21 AS-ODN decreased IC 50 and increased Cisplatin sensitivity for A375 cells and A375/CDDP cells, which would be a new target of melanoma treatment.