RETRACTED: Physcion 8-O-β-glucopyranosideregulates cell cycle, apoptosis, and invasion in glioblastoma cells through modulating Skp2 (Retracted article. See vol. 144, 2021)

Glioblastoma multiforme (GBM) is the most common malignant glioma in the central nervous system. This study aimed to investigate the anti-tumor activity of physcion 8-O-beta-glucopyranoside (PG) in GBM cells. This showed that PG could significantly block cell cycle progression, induce apoptosis, and suppress invasion in both model GBM cell lines (U87 and U251). At the molecular level, PG repressed the expression of S-phase kinase protein 2 (Skp2), which was responsible for the anti-tumor effect of PG in GBM cells. The ectopic overexpression of Skp2 significantly abrogated the inducing effect of PG on apoptosis as well as the suppressing effect of PG on cell invasion. In contrast, the knockdown of Skp2 by short hairpin RNA enhanced the anti-tumor effect of PG in GBM cells. Moreover, the findings indicated that PG repressed the expression of Skp2 through generating reactive oxygen species and hence modulating AMPK/mTOR signaling.