Το evaluate the effect of L-Tetrahydropalmatine (L-THP) on the sensitivity of a cisplatin resistant ovarian cancer (OC) cell line. As miR-93 is reported to be overexpressed in OC and cisplatin resistance, we also evaluated its pathway in OC.
The levels of miR-93 were evaluated using RT-PCR and Luciferase assay was performed to confirm the target of miR-93. The extent of apoptosis was evaluated by Annexin V and propidium iodide (PI) staining, whereas Hoechst 33258 staining was done for identifying the number of apoptotic cells.
The cisplatin-resistant A2780/DDP cell line showed lower survival rate compared to control when incubated with L-THP along with cisplatin. L-THP caused G0/G1 cell cycle arrest and increased the sensitivity to cisplatin. Furthermore, we found that the levels of miR-93 in cisplatin-resistant cells were highly expressed compared to parental cells. L-THP suppressed the expression of miR-93 and increased the levels of PTEN, a crucial tumor suppressor in OC. It was further observed that the cells transfected with PTEN siRNA showed increased survival compared with the control group and this phenomenon could be reversed by the AKT inhibitor Triciribine. The A2780 cells treated with PTEN siRNA showed similar survival rate to the cells with miR-93 overexpression.
The findings of this study suggested L-THP increased the sensitivity of ovarian cancer cells to cisplatin via modulating miR-93/PTEN/AKT pathway in A2780/DDP ovarian cancer cell line.