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

Background: β-sitosterol is a natural plant steroidal compound with anti-cancer properties against various tumors. This work attempts to explore the inhibitory effect of β-sitosterol on the progression of lung adenocarcinoma (LUAD) and further analyze its targets.

Methods: In this work, 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 including quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blot (WB), CCK-8, flow cytometry, immunohistochemistry (IHC), and immunofluorescence (IF) experiments. The regulatory influence of β-sitosterol on the glycolysis pathway was validated by detecting glucose consumption and lactate production, as well as extracellular acidification rate (ECAR) and oxygen consumption rate (OCR).

Results: In this project, we unearthed that CHRM2 was a protein that directly binds to β-sitosterol. In vitro, CHRM2 overexpression repressed the apoptosis rate and expression of apoptosis-related proteins and promoted glycolysis, while the addition of lonidamine attenuated the inhibitory effect conferred by CHRM2 overexpression on LUAD apoptosis. 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.

Conclusion: Our project emphasized 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 can provide new evidence for supporting the potential use of β-sitosterol as a therapeutic agent for LUAD.