Effects of transfection with antisense microRNA-155 oligonucleotides on the growth of a human cutaneous squamous cell carcinoma cell line A431

Objective To evaluate effects of antisense oligonucleotides against microRNA-155 (miRNA-155) on the proliferation, apoptosis, migration and invasion of a human cutaneous squamous cell carcinoma cell line A431. Methods A431 cells were divided into 3 groups: nonsense oligonucleotide group transfected with nonsense control oligonucleotides using liposomes, antisense oligonucleotide group transfected with antisense oligonucleotides against microRNA-155 using liposomes, and blank control group treated with Dulbecco′s minimum essential medium (DMEM) containing Lipofectamine 2000. Real-time quantitative polymerase chain reaction (qRT-PCR) was performed to determine the expression of miRNA-155 in A431 cells. Methyl thiazolyl tetrazolium (MTT) assay was conducted to estimate cellular proliferative activity at 24, 36, 72, 96 and 120 hours after transfection, flow cytometry to detect apoptosis and cell cycle changes, and Transwell assay to evaluate the migration and invasion of A431 cells. Statistical analysis was carried out by one-way analysis of variance (ANOVA) for intergroup comparisons and by least significant difference (LSD) -t test for multiple comparisons. Results After transfection, there were significant differences in the expression of miRNA-155 among the nonsense oligonucleotide group, antisense oligonucleotide group and blank control group (0.98 ± 0.02, 0.28 ± 0.18, 1.00 ± 0.01 respectively, F = 634.57, P < 0.001) , and the expression of miRNA-155 was significantly lower in the antisense oligonucleotide group than in the blank control group and nonsense oligonucleotide group (both P < 0.05) . At 72, 96 and 120 hours, there were significant differences in the survival rate of A431 cells among the 3 groups (all P < 0.05) , and the antisense oligonucleotide group showed a significantly lower survival rate of A431 cells compared with the blank control group and nonsense oligonucleotide group (all P < 0.05) . Additionally, the proportions of cells at G0/G1 phase and at S phase, and the cellular proliferative index all significantly differed among the 3 groups (F = 23.46, 36.81, 19.35, respectively, P < 0.01) . The antisense oligonucleotide group showed significantly higher proportion of cells at G0/G1 phase (74.63% ± 2.13%) , but lower proportion of cells at S phase (9.88% ± 1.83%) and cellular proliferative index (25.36 ± 2.13) compared with the blank control group (62.92% ± 2.56%, 18.86% ± 2.78%, 37.08 ± 2.56, respectively, all P < 0.05) and nonsense oligonucleotide group (63.75% ± 3.06%, 18.33% ± 3.72%, 36.25 ± 3.06, respectively, all P < 0.05) . Additionally, the antisense oligonucleotide group showed significantly lower numbers of migratory cells and invasive cells compared with the blank control group and nonsense oligonucleotide group (all P < 0.05) . Conclusion Transfection of A431 squamous cell carcinoma cells with antisense miRNA-155 oligonucleotides can decrease the expression of miRNA-155, effectively inhibit the proliferation, migration and invasion of A431 cells, and promote cell apoptosis. Key words: Carcinoma, squamous cell; MicroRNAs; RNA, antisense; Cell proliferation; Apoptosis