Objective: To explore the effect of microRNA-21 (miR-21) antisense oligonucleotide on the biological characteristics of human cervical squamous carcinoma cell lines SiHa in vivo and in vitro.
Methods: Specific phosphorothioate antisense oligodeoxynucleotides targeting miR-21 were synthesized and transfected into cervical cancer cells in vitro. Expression of miR-21 in SiHa after transfection was detected by real-time RT-PCR. The cell proliferation was evaluated by MTT assay and colony formation experiment. The cell apoptosis was analyzed by annexin V-FITC/PI analysis. The inhibitory effect of miR-21 antisense oligonucleotide on tumor growth was evaluated by tumor growth curves and immunohistochemistry (MaxVision method). H-E staining was used to document morphological changes and fluorometric TUNEL assay was to detect the apoptotic activity.
Results: After the transfection of antisense miR-21, the expression of miR-21 decreased along with an obvious growth inhibition, compared with that of the control groups (P < 0.05). Colony formation of both cell lines was markedly inhibited with antisense miR-21 (55.6% ± 1.4%), as compared with that in the negative group (98.3% ± 2.0%, P < 0.05). Flow cytometry assay showed that antisense miR-21 expression significantly enhanced the cell apoptosis (6.7% ± 1.3% and 29.4% ± 1.7%, P < 0.05). The tumor-forming rates of miR-21 transfected group, and negative control groups were 3/8 and 6/8, respectively (P < 0.05). Ki-67 proliferative marker staining decreased significantly (42% vs 90%) in the transfected group compared with negative control groups. Extensive dead tumor cells were seen in the miR-21 transfected cells along with a marked increase of apoptosis (P < 0.05).
Conclusion: Targeted antisense oligonucleotide miR-21 effectively suppresses the growth of cervical carcinoma SiHa cells both in vitro and in vivo through an induction of apoptosis.