The active ingredient β-sitosterol in Ganoderma regulates CHRM2-mediated aerobic glycolysis to induce apoptosis of lung adenocarcinoma cells.

Abstract

β-sitosterol is a natural plant steroidal compound with anti-cancer properties against various tumors. This work explored the inhibitory effect of β-sitosterol on the progression of lung adenocarcinoma (LUAD) and further analyzed its targets. We applied network pharmacology to obtain the components and targets of Ganoderma spore powder. The biological functions of β-sitosterol and CHRM2 were studied using the homograft mouse model and a series of in vitro experiments involving quantitative reverse transcription polymerase chain reaction, western blot, CCK-8, flow cytometry, immunohistochemistry and immunofluorescence. The regulatory influence of β-sitosterol on the glycolysis pathway was validated by measuring glucose consumption and lactate production, as well as the extracellular acidification rate and oxygen consumption rate. We found that CHRM2 binds directly to β-sitosterol. In vitro, CHRM2 overexpression repressed the apoptosis rate and expression of apoptosis-related proteins in LUAD cells, and promoted glycolysis, while the addition of lonidamine attenuated the apoptosis-inhibiting effect conferred by CHRM2 overexpression. Furthermore, β-sitosterol hindered glycolysis as well as the growth of tumors in vitro and in vivo. CHRM2 overexpression reversed the effect of β-sitosterol on the biological behavior of LUAD cells. Our results emphasize that CHRM2 is a direct target of β-sitosterol in LUAD cells. β-sitosterol can repress the glycolysis pathway, exerting an anti-tumor effect. These findings provide new support for the use of β-sitosterol as a therapeutic agent for LUAD.