| Bladder transitional cell cancer is the most common malignancy in urinary system, and its morbidity has increased during these years. Superficial tumors comprises of more than two thirds of bladder transitional cell cancers and can usually be treated with transurethal resection. Treatment difficulty and poor prognosis ensued once muscle invasive tumors occurred. There has not yet been any markers which can be used to early detect the occurrence or the tendency of muscle invasive disease in bladder transitional cell cancer. Large quantities of researches indicated that angiogenesis is essential for growth, invasion and metastasis of solid tumors. The increased activity of vascular growth factors plays important roles in tumor angiogenesis. It has been rescently demonstrated that platelet-derived endothelial cell growth factor (PD-ECGF) plays an important role in the growth, invasion and metastatic process of several maligant tumor. The enzyme activity of PD-ECGF, which is identical to thymidine phosphorylase (TP), is an essential enzyme to activate 5'-deoxy-5-fluorouridine (5'DFUR) and 5-fluorouracil (5FU) in vivo. The anticancer activity of 5'DFUR and 5FU have been demonstrated increased by enzyme activity of PD-ECGF/TP in gastric, colon and breast cancer cells.This research investigated regulation effect of interferon gamma on PD-ECGF/TP mRNA and protein expression in RT-4 and T24 bladder transitional cancer cells using RT-PCR and Western blot, respectively. The relationship between these regulation effects and in vitro cytotoxicity of 5'DFUR or 5FU in RT-4 and T24 cells was also analyzed. The PD-ECGF/TP mRNA and protein expressions in resected bladder transitional carcinoma tissues were determined by RT-PCR and immunohistochemistry, repectively. The relationship between PD-ECGF/TP mRNA and protein expressions and biological behaviors of bladder cancer such as tumor invasion, grade and recurrence was also discussed.Section one Interferon gamma-induced up-regulation of PD-ECGF/TP enhances the cytotoxicity of 5'DFUR and 5FU in RT-4 and T24 bladder transitional cancer cells. Materials and MethodsRT-4 and T24 bladder cancer cells represents low-grade and high-grade bladder transitional cancer cells, respectively. RT-PCR and Western blot were used to analyze the mRNA and protein expressions in these cells. MTS method was performed to determine the cytotoxicity of 5'DFUR and 5FU and mitomysin C (MMC).Results Interferon gamma –untreated RT-4 or T24 bladder cancer cells expressed low level of PD-ECGF/TP mRNA. Markedly increased expression of PD-ECGF/TP mRNA was shown in RT-4 and T24 cells in a positive dose-related manner after interferon gamma treatment. The PD-ECGF/TP mRNA started to increase after 4 hours of interferon gamma treatment and reached the highest after 16 hours. Protein expression of PD-ECGF/TP as detected by Western blot showed increased expression in a dose-dependent manner similar to mRNA expression. No statistically significant cytotoxicity of interferon gamma only was shown at a dose up to 10000 U/ml even after 48 hours of treatment in both RT-4 and T24 cells. Interferon gamma pre-treatment at 50 U/ml for 24 hours significantly enhanced the sensitivity of RT-4 and T24 bladder cancer cells to 5'DFUR and 5FU. Interferon gamma reduced the IC50 of 5'DFUR from (9.7±0.2)mmol/L to (3.3±0.9)mmol/L (t = 8.64, P = 0.001) and IC50 of 5FU from (130.0±3.6)?mol/L to (49.3±18.4)?mol/L (t = 3.52, P = 0.02) in RT-4 cells. IC50 of 5'DFUR decreased from (16.0±3.9)mmol/L to (6.2±0.9)mmol/L (t = 2.82, P = 0.048) and from (826.7±155.1)?mol/L to (346.7±38.9)?mol/L (t = 3.68,P = 0.021) of 5FU after interferon gamma pre-treatment in T24 cells. IC50 of MMC, which is not activated by PD-ECGF/TP, was not altered by interferon gamma.Section two PD-ECGF/TP mRNA expression in bladder transitional cell cancerMaterials and MethodsA total of 35 cases with pathologically diagnosed bladder transitional cell cancer were included in this study, including 14 Ta, 12...
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