ANALYSIS OF MAP-KINASE IN THE BLADDER CANCER AND TARGETED MOLECULAR STRATEGIES BASED ON THE BLOCKADE OF THE MAP-KINASE PATHWAYS

背景：丝裂原活化蛋白激酶(MAPK)级联信号通路在细胞外信号转化为调控生长和分化的反应中起着至关重要的作用。研究了MAPK通路的一种特异性抑制剂对尿路上皮癌细胞周期依赖性激酶的抑制作用。材料和方法：检测15例正常尿液标本、20例膀胱癌患者尿液标本、20例正常尿路上皮、40例膀胱癌患者尿液标本中ELK-1mRNA的表达。我们通过研究MEK1/2抑制剂对6个人尿路上皮癌细胞系的作用，探讨MAPK在膀胱癌中的抑制作用。结果：正常尿液和正常尿路上皮组织中均未检测到ELK-1mRNA的表达。膀胱癌患者尿液中有20.0%、膀胱癌患者尿液中有70.0%的细胞表达Elk-1mRNA。膀胱癌组织中Elk-1mRNA的表达与病理分级、分期无关。经MEK1/2抑制剂处理的6例膀胱癌标本中可见多个TUNEL阳性细胞。MAPK磷酸化检测结果显示，MAPK通路在6株膀胱癌细胞系中的表达水平不同。TUNEL法检测MEK抑制剂可诱导UC细胞发生轻微的细胞凋亡，而MAPK检测中未见其抑制MAPK的磷酸化。结论：单纯MAPK磷酸化可能不参与膀胱癌的发生和增殖。因此，细胞核中ELK-1的激活可能有助于癌变而不是肿瘤的进展。

Background: The mitogen-activated protein kinase (MAPK) cascade plays a crucial role in the transduction of extra cellular signals into responses governing growth and differentiation. The effects of a specific inhibitor of the MAPK kinase pathway on inhibition of urothelial cancer cell cycle-dependent kinases have been examined. Materials and Methods: We evaluated the expression of Elk-1 mRNA in 15 normal urine samples or 20 urine sample of the patient with bladder cancer, and 20 normal urothelial or 40 bladder cancer specimens. We investigated inhibition effect of MAPK activation in bladder cancer by studying the effect of MEK1/2 inhibitor on a panel of six human urothelial carcinoma cell lines. Results: Elk-1 mRNAexpression was not detected in any of the normal urine samples and normal urothelial mucosa. In the other, Elk-1 mRNA expressed all of the human transitional cell carcinoma cell lines, 20.0% urine sample of the patient with bladder cancer and 70.0% bladder cancer specimens. No relations were observed between the Elk-1 mRNA expression and pathological grade or staging in bladder cancer specimens. Several TUNEL positive cells were present in specimens 6 bladder cancer cells treated with MEK1/2 inhibitor. The expression level of the MAPK pathway in six bladder cancer cell lines using MAPK phosphorylation assay were various. The MEK inhibitor induced slightly apoptosis in UC cell lines by TUNEL methods, but not inhibited phosphorylation of MAPK in the MAPK Assays. Conclusions: Only MAPK phosphorylation may not contribute to carcinogenesis and tumor proliferation in the bladder cancer. As a result, activation of Elk-1 in nucleus may contribute to carcinogenic transformation rather than in tumor progression.