Gentiopicroside inhibits retinoblastoma cell proliferation, invasion, and tumorigenesis in nude mice by suppressing the PI3K/AKT pathway.

Retinoblastoma is a prevalent pediatric intraocular tumor. The suppressive effect of gentiopicroside (GPS) has been reported on various tumors. This study sought to determine the effect of GPS on retinoblastoma cell proliferation, apoptosis, invasion, and epithelial-mesenchymal transition (EMT), and tumorigenesis in nude mice. The effect and mechanism of GPS on growth, apoptosis, invasion, and EMT were determined by cell counting kit-8 (CCK-8), western blot, flow cytometry, and transwell assays in retinoblastoma cells. Y79 cells were injected into the vitreous cavity of BALB/c‑nude mice to construct a retinoblastoma mouse model. Tumor growth and mouse weight were monitored for sequential 5 weeks. The effect of GPS in vivo was assessed by immunohistochemistry (IHC), terminal deoxynucleotidyl transferase deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL), and western blot assays. GPS decreased the cell viability of both Y79 and Weri-Rb1 cells with the IC50 of 18.85 μM and 27.57 μM, respectively. Besides, GPS reduced the relative expression of proteins involved in proliferation and EMT, and the number of invading cells, while increased the apoptosis rate and the relative expressions of apoptosis proteins in retinoblastoma cells. Mechanically, GPS decreased the relative protein level of PI3K/AKT pathway, which was then recovered after 740 Y-P was applied. Correspondingly, 740 Y-P reversed the inhibitory effect of GPS on growth, invasion, and EMT, and the increased effect of GPS on apoptosis. Additionally, GPS decreased tumor volume and weight as well as the relative level of Ki-67, VEGF, p-PI3K/PI3K, and p-AKT/AKT, while increased the apoptosis rate in vivo. GPS inhibited retinoblastoma cell proliferation and invasion via deactivating the PI3K/AKT pathway in both cell and animal models.