Kaempferol targets estrogen-related receptor α and inhibits cell proliferation and invasion in retinoblastoma via Wnt/β-catenin signaling pathway

Retinoblastoma is a pediatric retinal tumor caused by mutational inactivation of the tumor suppressor pRb, and the present study aims to examine the role of kaempferol in retinoblastoma and explore its underlying molecular mechanisms. The mRNA and protein expression levels were measured by quantitative real time PCR (qRT-PCR) and western blot, respectively; cell growth and invasion was determined by CCK-8 assay, colony formation assay, and cell invasion assay; cell cycle was determined by flow cytometry, and cell apoptosis was examined by flow cytometry and TUNEL assay. The target of kaempferol was confirmed by luciferase reporter assay. Kaempferol inhibited cell growth and invasion in a concentration-dependent manner in retinoblastoma SO-RB50 cells. Clinical sample analysis showed that estrogen-related receptor α (ERRα) is up-regulated in retinoblastoma tissues and SO-RB50 cells. Luciferase reporter assay further showed that kaempferol exerted its effect via targeting ERRα. Mechanistic study also showed that kaempferol caused G2/M arrest as well as apoptosis in SO-RB50 cells and also suppressed Wnt/β-catenin signaling via targeting ERRα. In conclusion, our studies indicate that kaempferol targets ERRα and inhibits cell proliferation and invasion in retinoblastoma via Wnt/β-catenin signaling pathway.