Expression Of EZH2 And PTEN In Prostate Cancer And Its Clinicopathologic Significance

Objective To study the MDR-reversing effect of arsenic trioxide on human hepatocellular carcinoma Bel-7402/ADM in vitro and its potential mechanism.Methods Multidrug resistant cell line Bel-7402/ADM of human hepatocellular carcinoma was established in nude mice by orthotopic transplantation; MTT assay was used to test multidrug resistence of Bel-7402/ADM ;MTT assay was used to test the toxicity of the arsenic trioxide and the chemosensitivity to chemotherapeutics in arsenic trioxide-treated Bel-7402 and Bel-7402/ADM cell lines; Flow cytometry was used to determine cell apoptosis by Annexin V-FITC-PI double staining; The expression of Bcl-2 and Bax was measured by RT-PCR and Western blotting.Results1. The resistance of cell Bel-7402/ADM which was induced by Orthotopic liver transplantation in nude mice eight weeks of application of ADM to ADM and CDDP were increased by 13.58 and 12.25 times respectively, and its resistance to MMC and 5-FU were not significant. RT-PCR detected Bcl-2mRNA high expression and BaxmRNA low expression in Bel-7402/ADM, while Western blotting detected Bcl-2 protein high expression and Bax protein low expression in Bel-7402/ADM, and the difference was statistically significant compared with cell Bel-7402 (P<0.01).2. Cytotoxicity Detection of As₂O₃ to Bel-7402, Bel-7402/ADM. The results showed that when As₂O₃ was at 0.25mg/L, Bel-7402, Bel-7402/ADM cytotoxicity was not ob- vious, however, a dose-response relationship was found when exceed this concentrat- ion. The IC50 of As₂O₃ to Bel-7402, Bel-7402/ADM were 0.91±0.04mg / L and 0.95±0.04mg / L respectively .3. As₂O₃ can improve sensitivity of the resistant cells to chemotherapeutic drug. The IC50 of the ADM and CDDP on the Bel-7402, Bel-7402/ADM were significantly reduced after the use of 0.1 mg / L concentration of As₂O₃. The reversal multiples of drug resistance of As₂O₃ to Bel-7402/ADM were ADM: 2.85-fold and CDDP: 3.38-fold respectively.4. The amount of cell-free agent As₂O₃ combined ADM can induce the apoptosis of Bel-7402 and Bel-7402/ADM, which was significantly different when ADM alone was used. Compared with the control group, early apoptotic cells mortality rate was significantly higher and the difference was statistically significant after the combination of experimental group of ADM and non-cytotoxicity As₂O₃(P<0.05).5. As₂O₃ can down-regulate the expression of Bcl-2 of Bel-7402/ADM cells, while increase Bax expressionof Bel-7402/ADM cells. After As₂O₃ acted on Bel-7402/AD- M cells, PR-PCR and Western blotting results showed that the Bcl-2 expression was reduced while the Bax expression was increased. The difference was statistically significant(P<0.01). Bcl-2's expression was still higher than parents group(P<0.05), while Bax's expression was not significantly different compared with parents group(P>0.05).Conclusions1. The Establishment of multidrug resistance in a model of orthotopic transplantation of human hepatocellular carcinoma in nude mice was in a short time and its reliability and validity were good. The multidrug resistance mechanisms of hepatocellular carcinoma may be related to high expression of Bcl-2 and low expression of Bax leading to apoptosis resistence. 2. As₂O₃ was a in the role of human liver cancer cells in vitro reversal of multidrug re- sistance, and may be it was related to reduced expression of Bcl-2, increased expres- sion of Bax, and the promotion of drug-resistant cell easy to apoptosis.3. As₂O₃ in vitro showed a strong reversal of the role of multidrug resistance of hepatocellular carcinoma, and provides a new way for clinical liver cancer chemotherapy.