Lobetyolin inhibits the proliferation of breast cancer cells via ASCT2 down-regulation-induced apoptosis

This study aimed to investigate the anti-cancer effect of lobetyolin on breast cancer cells. Lobetyolin was incubated with MDA-MB-231 and MDA-MB-468 breast cancer cells for 24 h. Glucose uptake and the mRNA expression of GLUT4 (SLC2A4), HK2 and PKM2 were detected to assess the effect of lobetyolin on glucose metabolism. Glutamine uptake and the mRNA expression of ASCT2 (SLC1A5), GLS1, GDH and GLUL were measured to assess the effect of lobetyolin on glutamine metabolism. Annexin V/PI double staining and Hoechst 33342 staining were used to investigate the effect of lobetyolin on cell apoptosis. Immunoblot was employed to estimate the effect of lobetyolin on the expression of proliferation-related markers and apoptosis-related markers. SLC1A5 knockdown with specific siRNA was performed to study the role of ASCT2 played in the anti-cancer effect of lobetyolin on MDA-MB-231 and MDA-MB-468 breast cancer cells. C-MYC knockdown with specific siRNA was performed to study the role of c-Myc played in lobetyolin-induced ASCT2 down-regulation. Myr-AKT overexpression was performed to investigate the role of AKT/GSK3 beta signaling played in lobetyolin-induced down-regulation of c-Myc and ASCT2. The results showed that lobetyolin inhibited the proliferation of both MDA-MB-231 and MDA-MB-468 breast cancer cells. Lobetyolin disrupted glutamine uptake via down-regulating ASCT2. SLC1A5 knockdown attenuated the anti-cancer effect of lobetyolin. C-MYC knockdown attenuated lobetyolin-caused down-regulation of ASCT2 and Myr-AKT overexpression reversed lobetyolin-caused down-regulation of both c-Myc and ASCT2. In conclusion, the present work suggested that lobetyolin exerted anti-cancer effect via ASCT2 down-regulation-induced apoptosis in breast cancer cells.