Effect Of Glycyrrchizin On Inhibition Of Bladder Cancer T24 Cells And The Mechanism

Background and objective: Bladder cancer is common genitourinary neoplasm. The incidence of male urogenital neoplasms abroad, second only to prostate cancer tumors, ranking 2nd, as in the domestic accounts for the first, the urinary bladder transitional cell cancer often take surgery, and treat by chemotherapy medicine after the operation. However, the efficacies of postoperative chemotherapy drugs are less than ideal at present. More than half of the patients who have retained the bladder will be recurrence, and 10%-15% of them will increase the tendency of malignancy. Looking for the drugs which have high performance and low toxicity to improve bladder cancer treatment has a positive meaning. Therefore, the discovery and development of new anticancer drugs is still a very difficult and long-term mission and challenges for the medical profession.Traditional Chinese medicine has the unique advantage in treatment, rehabilitation, health and other aspects. However, the research in prevention and treatment of bladder cancer is still rare. There are few reports of prevention and cure on bladder cancer. Some new researches showed that Glycyrrchizin (GL) could suppress the proliferation of some cancer cells as galactophore cancer, hepatic cance and prostatic cancer in vitro. To study the effects of GL on biology characters of T24 bladder cancer cells, and its associated mechanisms of apoptosis, we treated T24 cells with GL by several techniques, and maybe provide some theoretical evidences for developing quercetin as an anti-tumor drug.Methods:1 T24 bladder cancer cells were treated with GL in vitro and observe the amount of treatment effect. Afiter using the different concentrations (6.25, 12.5, 25, 50, 100, 200, 400, 800μmol/L), dealing with different time (24, 48 and 72 h), Morphologic changes were studied with the optical microscope. Effect of GL on proliferation of T24 cells was analyzed by MTT assay.2 After 48 h at different concentrations (25, 50, 100, 200, 400μmol/L) GL, Cell cycle and apoptosis rate of SW480 cells induced with GL were detected by flowcytometry.3 After treatment with quercetin, protein expression of cyclin B1 in T24 cells was analyzed by Western blot analysis.Results:1 Glycyrrhizin inhibited T24 cell proliferationDifferent concentrations of glycyrrhizin effect T24 cells after 24 h, suspension cells increased, the cells became smaller and round, Cell nucleus got pyknosis and broken, cells particles increased, and cell debris in the culture medium increased. By MTT analysis, it is shown that proliferation of T24 cells was significantly inhibited by GL at concentrations of 12.5, 25, 50, 100, 200, 400, 800μmol/L (P<0.01), By LSD-t test showed that at the same time the drug treatment group and control group, the difference had statistical significance (P <0.01); The same concentration, 24, 48, 72 h comparison between the difference was statistically significant (P<0.01), and showing a dose- and time-dependent manner.2 Glycyrrhizin induced T24 cell cycle arrest and apoptosisAfter treatment with 25,50,100,200,400μmol GL for 48h, the percentages of T24 cells at G0/G1 phase were increased markedly, and those at G2/M and S phase were decreased (P<0.01). After incubated with 200μmol/L GL for 48 h, apoptosis rate of T24 cells increased from (3.05±0.44)% of control group to (41.11±5.29 )%(P<0.01).3 GL can down-regulate Expression of PCNA in T24 cells markedly by quercetin in a dose-dependent mannerGlycyrrhizin can significantly reduced expression of PCNA protein. After treat T24 cell with glycyrrhizin (50,100,200,400μmol/L) for 48 hours, , Western blot test results to suggest tha PCNA protein expression levels are decreased With the concentration of glycyrrhizin, Expression of PCNA in T24 cells could be down-regulated by quercetin in a dose-depedent manner .4 GL can down-regulate Expression of Bcl-2 and up-regulate Expression of Bax in T24 cells markedly by quercetin in a dose-dependent manner.Western blot results showed that glycyrrhizin (50,100,200,400μmol / L) treat T24 cells for 48 hours, with the role of the increase in the concentration, the expression of Bcl-2 gradually decreased, while Bax expression was gradually increased, showing a significant The concentration-dependent, the ratio of Bax/Bcl-2 of T24 cells gradually increased.Conclusions: Glycyrrhizin can significantly inhibit T24 cell proliferation, possibly through reduced expression of PCNA protein in the T24 cell cycle arrest in G0/G1 phase; glycyrrhizin can induce apoptosis, and the mechanism may be through down-regulating Bcl-2 protein in T24 cells expression and up-regulating Bax protein expression, increased Bax/Bcl-2 ratio of relevant, showing a significant dose-dependent.