STCB Inhibits HepG2 Cell Proliferation by Regulating Ras Signaling and Autophagy

The role of traditional Chinese medicine in cancer treatment is becoming increasingly pivotal. Tupistra chinensis Baker (STCB), a member of the Lily family, is an herbal plant with antipyretic and detoxifying properties. It has also been used to alleviate abdominal distension. Previous studies have shown that saponin extracted from STCB inhibits proliferation of hepatic carcinoma (HCC) cells. The present study aimed to explore the mechanisms implicated in the regulation of HCC progression by STCB.

The impact of STCB on HepG2 hepatoblastoma cell proliferation in vitro was evaluated using Cell Counting Kit-8 assay. The levels of Ras signaling-related and autophagy-related proteins in cancer cells and tumor tissues were determined using Western blot, immunohistochemistry, and immunofluorescence assays.

STCB significantly inhibited cell growth similar to Salirasib in vitro. STCB combined with Salirasib resulted in a higher inhibition rate of HepG2 cell growth. STCB treatment also suppressed Ras expression and phosphorylation of its downstream proteins. STCB treatment also upregulated levels of autophagy-related proteins. In mouse xenograft models, STCB impeded growth of subcutaneously transplanted hepatic tumors as well as inhibited Ras signaling, similar to cisplatin treatment.

STCB significantly inhibited HepG2 cell proliferation by downregulating Ras signaling-related proteins and inducing autophagy.