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Ursolic acid induces human hepatoma cell line SMMC-7721 apoptosis via p53-dependent pathway
Yan-Xia Yu1, Zhen-Lun Gu, Jiang-Lin Yin
1Soochow Institute of Chinese Materia Medica, Suzhou, Suzhou, Jiangsu 215007, China.
Background:
Ursolic acid (UA) is a ubiquitous molecule in the plant kingdom with specific anticancer effects that have been shown in vitro and in vivo. Although UA can inhibit the proliferation of liver cancer cells and induce apoptosis of many types of tumor cells, the molecular mechanism of its anti-hepatoma activity is still not well defined. The objective of this study was to investigate the inhibitory effect and mechanisms of UA on the human hepatoma cell line SMMC-7721.
Methods:
After treatment with UA, the growth inhibition of SMMC-7721 cells was assessed by MTT assay. Cells were also evaluated by flow cytometric analysis, Wright-Giemasa staining, Hoechst 33258 staining and transmission electron microscope after they were induced by UA. DNA microarray technology was used to investigate the gene expression pattern of SMMC-7721 cells exposed to UA 40 micromol/L. The molecular mechanism of cells death was analyzed by real-time RT-PCR and Western blotting.
Results:
The proliferation of SMMC-7721 cells was significantly inhibited in a dose- and time-dependent manner after UA treatment. UA induced cell cycle arrest and apoptosis. The DNA microarray analysis indicated that 64 genes were found to be markedly up- or down-expressed, including GDF15, SOD2, ATF3, and fos. The result of Western blotting showed the apoptotic proteins p53 and Bax were up-regulated while the anti-apoptotic protein Bcl-2 was down-regulated. Real-time RT-PCR confirmed UA could up-regulate the mRNA expressions of GDF15, SOD2, ATF3 and down-regulate the mRAN expression of fos. Meanwhile these effects were partly blocked by pretreatment with the p53 inhibitor Pft-alpha.
Conclusion:
Activation of the p53 pathway is involved in UA inhibition of SMMC-7721 human hepatocellular carcinoma cell growth and induction of apoptosis.
Insights
Ursolic acid (UA) inhibits human hepatoma cell growth and induces apoptosis by activating the p53 pathway. This study clarifies the molecular mechanisms behind UA's anti-cancer effects in liver cancer cells.
Area of Science:
- Molecular Biology
- Cancer Research
- Pharmacology
Background:
- Ursolic acid (UA) exhibits anticancer properties against various tumor cells.
- The precise molecular mechanisms of UA's anti-hepatoma activity remain incompletely understood.
- This study investigates UA's effects on the SMMC-7721 human hepatoma cell line.
Purpose of the Study:
- To elucidate the molecular mechanisms underlying the inhibitory effects of Ursolic acid (UA) on human hepatoma cell line SMMC-7721.
- To determine if UA induces cell cycle arrest and apoptosis in SMMC-7721 cells.
- To identify specific genes and proteins modulated by UA treatment.
Main Methods:
- Cell proliferation was assessed using MTT assays.
- Apoptosis and cell cycle arrest were evaluated via flow cytometry, Hoechst staining, and electron microscopy.
- Gene expression profiling was performed using DNA microarrays, with validation by real-time RT-PCR and Western blotting.
Main Results:
- UA significantly inhibited SMMC-7721 cell proliferation in a dose- and time-dependent manner.
- UA treatment led to cell cycle arrest and induced apoptosis, evidenced by altered expression of key apoptotic proteins (p53, Bax, Bcl-2).
- Microarray analysis revealed differential expression of genes including GDF15, SOD2, ATF3, and fos, with RT-PCR confirming these changes.
Conclusions:
- Ursolic acid effectively inhibits human hepatocellular carcinoma cell growth.
- The p53 signaling pathway plays a crucial role in UA-induced apoptosis and growth inhibition.
- UA's molecular mechanisms involve the modulation of specific pro-apoptotic and stress-response genes.
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