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Anti-proliferating effects of ginsenoside Rh2 on MCF-7 human breast cancer cells
Abstract:
Ginsenoside Rh2 (G-Rh2) isolated from the root of Panax ginseng has been shown to have anti-cancer proliferation, differentiation and chemopreventive effects in certain cancer cell types. We investigated the mechanism of G-Rh2-induced growth inhibition in MCF-7 human breast carcinoma cells. G-Rh2 significantly inhibited the cell growth in a concentration-dependent manner, which effect was reversible, and induced a G1 arrest in cell cycle progression. G-Rh2 treatment down-regulated the protein level of cyclin D3 but upregulated the expression of cyclin-dependent kinase (Cdk) inhibitor p21WAF1/CIP1. The increased levels of p21 were associated with increased binding of p21 and Cdk2 concomitant with marked decrease in Cdk2 and cyclin E-dependent kinase activities with no changes in Cdk2 and cyclin E expression. G-Rh2 markedly reduced the phosphorylated retinoblastoma protein (pRb) and enchanced association of unphosphorylated pRb and the transcription factor E2F-1. These data suggest that G-Rh2 inhibited the growth of MCF-7 cells, by inducing protein expression of p21 and reducing the protein levels of cyclin D which resulted in the down-regulation of cyclin/Cdk complex kinase activity, decreasing phosphorylation of pRb, and inhibiting E2F release.
Insights
Ginsenoside Rh2 (G-Rh2) inhibits human breast cancer cell growth by halting the cell cycle. This natural compound upregulates p21 expression and downregulates cyclin D, ultimately blocking cell proliferation.
Area of Science:
- Pharmacology
- Molecular Biology
- Cancer Research
Background:
- Ginsenoside Rh2 (G-Rh2), derived from Panax ginseng, exhibits anti-cancer properties.
- Previous studies indicate G-Rh2's potential in cancer cell proliferation, differentiation, and chemoprevention.
Purpose of the Study:
- To elucidate the mechanism behind G-Rh2-induced growth inhibition in MCF-7 human breast carcinoma cells.
Main Methods:
- Investigated G-Rh2's effect on cell cycle progression in MCF-7 cells.
- Analyzed protein levels of cyclin D3, p21WAF1/CIP1, and retinoblastoma protein (pRb).
- Assessed the activity of cyclin-dependent kinases (Cdks) and their interactions with inhibitors and substrates.
Main Results:
- G-Rh2 demonstrated dose-dependent and reversible inhibition of MCF-7 cell growth.
- Induced a G1 phase arrest in the cell cycle.
- Downregulated cyclin D3 and upregulated p21WAF1/CIP1 expression.
- Increased p21 binding to Cdk2, decreasing Cdk2 and cyclin E kinase activities.
- Reduced pRb phosphorylation and enhanced pRb-E2F-1 association.
Conclusions:
- G-Rh2 inhibits MCF-7 cell growth by inducing p21 and reducing cyclin D, leading to decreased cyclin/Cdk activity.
- This mechanism results in reduced pRb phosphorylation and inhibited E2F release, effectively halting cell cycle progression.