Research Of Silibinin-induced Autophagy In Salivary Adenoid Cystic Carcinoma Cell Line ACC-M In Vitro

Part Ⅰ Expression and clinical significance of autophagy associated protein in salivary adenoid cystic carcinomaObjective The purpose of this study was to explore the expression of microtubule associated protein1light chain3(LC3) in salivary adenoid cystic carcinoma and investigate the role of autophagy in carcinogenesis of salivary adenoid cystic carcinoma.Methods The expression of LC3in group of adenoid cystic carcinoma (46specimens) and normal salivary tissues (23specimens) were detected by immunohistochemical staining.Results The positive rates of LC3were42.22%in adenoid cystic carcinoma and91.30%in normal salivary tissues. There is a significant difference between them (P<0.05).Conclusion The positive rates of LC3were lower in adenoid cystic carcinoma than in normal salivary tissues. This study suggests that autophagy may be related to the carcinogenesis of adenoid cystic carcinoma. Part II Research of silibinin-induced autophagy in salivary adenoid cystic carcinoma cell line ACC-M in vitroObjective The purpose of this study was to evaluate effect of silibinin on the proliferation and autophagy of human salivary adenoid cystic carcinoma cell line ACC-M in vitro. Methods The inhibitory effect on ACC-M cell proliferation at various concentrations of silibinin was assessed in vitro using the methyl thiazolyl tetrazolium (MTT) assay. The morphological observation was performed microscopically. The auto-fluorescent drug monodansyl cadaverine (MDC) and transmission electron microscope was used to detect autophagosome. The expression of autophagy key protein microtubule associated protein1light chain3(LC3) was analyzed by Western blot. All values were expressed as x±s of three independent experiments and analysed by ANOVA. P<0.05was considered significantly different.Results Silibinin concentration-time dependently inhibited the growth of ACC-M Cells. Silibinin induced autophagy of ACC-M cells. MDC staining showed increased bright green fluorescence densely gathered in the cytoplasm. The double membrane structure was observed under transmission electron microscope in the experimental group cells. Western blot show silibinin promoted the expression of LC3-I and LC3-Ⅱ.The ratio of LC3-Ⅱ/LC3-Ⅰ dependents on concentration and time.Conclusion Silibinin can significantly inhibit cell proliferation in vitro and promote autophagy in salivary gland adenoid cystic carcinoma ACC-M cells.