The mechanism of miR-15b inhibiting nasopharyngeal carcinoma cell proliferation

Nasopharyngeal carcinoma (NPC) accounts for the highest incidence in otolaryngology malignant tumors. MiRNAs can regulate malignant tumor growth as tissue sensitive tumor biomarkers. MiR-15b abnormally expressed in tumor and could be treated as biomarker. However, its expression and role in NPC cells is still unclear. This study aimed to investigate the mechanism of miR-15b in NPC occurrence and development. NPC cell line CNE2 was transfected with miR-15b mimics or inhibitor. Real time PCR was used to test miR-15b level. MTT assay was applied to determine cell proliferation. Transwell assay was performed to detected cell invasive ability. Real time PCR and Western blot were adopted to measure Bcl-2 expression. MiR-15b mimics transfection significantly promoted miR-15b overexpression and inhibited CNE2 cell proliferation (P < 0.05). Overexpressed miR-15b obviously downregulated Bcl-2 mRNA and protein expression (P < 0.05). On the contrary, miR-15b inhibitor markedly suppressed its level in NPC cells, promoted cell proliferation, and upregulated Bcl-2 mRNA and protein levels (P < 0.05). MiR-15b expression failed to impact tumor cell invasive ability (P > 0.05). MiR-15b can suppress NPC cell proliferation by downregulating Bcl-2 protein expression and promoting tumor cell apoptosis.