NF-κB signaling pathway mediates the anti-tumor effect of Ginsenoside Rg1 in glioblastoma

The identification of novel therapeutics for malignant glioblastoma multiforme (GBM) remains critical, given the tumor's highly invasive nature and poor prognosis. This study aimed to investigate the effect of Ginsenoside Rg1 (GS Rg1) on human GBM U87-MG and U251-MG cells.

Cell viability and proliferation was detected by MTT and BrdU assay, respectively. The level of NF-κB phosphorylation was quantified. The activity of the cathepsin B, Caspase-3 and Caspase-9 was measured by ELISA assay. The level of transcription of all genes were quantified by QRT-PCR assay.

GS Rg1 exerted potent dose-dependent anti-tumor effects on U87MG and U251MG cells. It significantly suppressed cell viability and proliferation, as determined by MTT and BrdU assays, respectively. Mechanistically, GS Rg1 induced apoptosis by activating caspase-3 and caspase-9 and shifting the Bax/Bcl-2 ratio in favor of pro-apoptotic signaling. This was accompanied by the downregulation of key anti-apoptotic (Survivin, Bfl-1) and proliferative (c-Myc, hTERT) genes. A central finding was the potent inhibition of the canonical NF-κB pathway, evidenced by reduced phosphorylation of NF-κB and decreased expression of its upstream kinase, IKK2. Consequently, GS Rg1 suppressed the transcription and activity of major NF-κB-dependent invasion mediators, including MMP-2, MMP-9, cathepsin B, uPA, and MMP-14. Furthermore, it inhibited the expression of the pH regulator CA9. Intriguingly, GS Rg1 upregulated the expression of NEMO, STAT3, and NHE1, suggesting compensatory mechanisms or alternative signaling modulation.

Our findings demonstrate that GS Rg1 exerts multi-faceted anti-tumor effects in glioblastoma cells by targeting the NF-κB signaling pathway.