Polyphyllin VII enhances the sensitivity of endometrial carcinoma cells to medroxyprogesterone acetate through upregulating miR‑33a‑5p expression

Endometrial carcinoma (EC) often exhibits resistance to hormone therapies, such as medroxyprogesterone acetate (MPA), highlighting the need for novel strategies to enhance therapeutic efficacy. The present study aimed to investigate the effects of polyphyllin VII (PPVII) on the efficacy of MPA in EC, focusing on the regulatory role of microRNA (miR)-33a-5p. Briefly, an MPA-resistant Ishikawa cell line (Ishikawa/MPA-R), maintained with 10 µM MPA, was established and transfected with negative control (NC) and miR-33a-5p inhibitors. Following treatment with PPVII and MPA, the proliferation capacity and apoptosis levels of the Ishikawa and Ishikawa/MPA-R cells were evaluated using reverse transcription-quantitative polymerase chain reaction, MTT assay, clonogenic assay, flow cytometry, western blotting and dual-luciferase assay. Next, the expression levels of miR-33a-5p and F-box and leucine rich repeat protein 16 (FBXL16) were measured, and the regulatory relationship between miR-33a-5p and FBXL16 was analyzed. Significant reductions in cell viability were observed in all groups following treatment with increased concentrations of MPA and PPVII, with the greatest effect observed in the combined MPA + PPVII group (P