RESUMEN
Although microRNA-155 (miR-155) is known to play an important role in many cancers, its expression and function in oral squamous cell carcinoma (OSCC) was not fully understood. Thus, in the present study, we investigated the expression of miR-155 and also the role this miR plays in OSCC. We used the OSCC cell line (CAL27) and paired tumor and non-tumor tissue samples from patients with OSCC in order to detect the expression of miR-155. Cell proliferation, migration and invasion assays were then undertaken in order to determine the effect of miR-155 on the biological behavior of CAL27 cells following transient transfection with miR-155 mimic and antagomir. The regulatory effect of miR-155 on its target gene B-cell CLL/lymphoma 6 (BCL6) and downstream gene cyclin D2 (CCND2) was also analyzed. We found that miR-155 expression in OSCC cell and tumor tissues was significantly higher than that of the controls. We noted that the miR-155 mimic enhanced CAL27 cell proliferation, migration and invasion ability, downregulated BCL6 levels, and increased cyclin D2 expression. However, we noted that abrogating miR-155 with the miR-155 antagomir suppressed CAL27 cell proliferation, migration and invasion, upregulated BCL6 and reduced cyclin D2 expression. These results indicate that miR-155 plays a tumor-promoting role in OSCC by regulating the BCL6/cyclin D2 axis.
Asunto(s)
Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patología , Ciclina D2/genética , Regulación Neoplásica de la Expresión Génica , MicroARNs/genética , Neoplasias de la Boca/genética , Neoplasias de la Boca/patología , Proteínas Proto-Oncogénicas c-bcl-6/genética , Adulto , Anciano , Anciano de 80 o más Años , Carcinoma de Células Escamosas/metabolismo , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular , Ciclina D2/metabolismo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neoplasias de la Boca/metabolismo , Invasividad Neoplásica , Proteínas Proto-Oncogénicas c-bcl-6/metabolismoRESUMEN
BACKGROUND: Clotrimazole is an antifungal imidazole derivative showing anti- neoplastic effect in some tumors, but its anticancer potential is still unclear in oral squamous cell carcinoma (OSCC). The aim of this study was to evaluate the antitumor effect of clotrimazole, and to investigate the possible mechanism of clotrimazole-mediated antitumor activity in OSCC. METHODOLOGY: In vitro experiments, the cell viability and clonogenic ability of three human OSCC cell lines CAL27, SCC25 and UM1 were detected after clotrimazole treatment by CCK8 assay and colony formation assay. Cell cycle progression and apoptosis were assessed by flow cytometry, and the involvement of several mediators of apoptosis was examined by western blot analysis. Then, the in vivo antitumor effect of clotrimazole was investigated in CAL27 xenograft model. Immunohistochemistry and western blot analysis were performed to determine the presence of apoptotic cells and the expression of Bcl-2 and Bax in tumors from mice treated with or without clotrimazole. RESULTS: Clotrimazole inhibited proliferation in all three OSCC cell lines in a dose-and time-dependent manner, and significantly reduced the colony formation of OSCC cells in vitro. Clotrimazole caused cell cycle arrest at the G0/G1 phase. In addition, clotrimazole induced apoptosis in OSCC cells, and significantly down-regulated the anti-apoptotic protein Bcl-2 and up-regulated the pro-apoptotic protein Bax. Notably, clotrimazole treatment inhibited OSCC tumor growth and cell proliferation in CAL27 xenograft model. Clotrimazole also markedly reduced Bcl-2 expression and increased the protein level of Bax in tumor tissues of xenograft model. CONCLUSION: Our findings demonstrated a potent anticancer effect of clotrimazole by inducing cell cycle arrest and cellular apoptosis in OSCC.