The mutation enhancement in human cell lines by serum factors from pancreatic cancer patients

在胰腺癌细胞中，碱基制度性突变被高度检测到。我们已经报道了胰腺癌患者的血清具有提高突变频率的能力。本研究通过研究血清对蛋白质和DNA代谢的影响，以阐明其增强活性的机制。我们已经发现，在抑制突变发生的早期步骤中，人干扰素可以诱导抗痛敏感蛋白水解酶的活性。因此，在胰腺癌患者的细胞中，用血清因子预处理，然后用紫外线照射，以β&lt；125&gt；i-纤维蛋白为底物，评估纤溶活性。这些因子是通过彩色柱层析法获得的。获得了提高紫外线诱导哇巴因耐药表型突变频率的组份样品，并通过基于PCR的差异斑点杂交分析检测到组分样品也显示了提高K-ras密码子12突变频率的能力。此外，该样品还增强了紫外线诱导的蛋白水解酶活性，RT-mRNA差异显示法检测到了几个基因的表达，提示胰腺癌患者的血清因子可能通过诱导多个基因的表达而促进K-ras密码子12突变。

In pancreatic cancer cells base institution mutation is very highly detected. We have reported that sera from pancreatic cancer patients have the ability to enhance the mutation frequency. In the present research effects of the sera on protein and DNA metabolism were studied, in order to clarify mechanism of the enhancement activity. We have already found that human interferon induce the activity of antipain-sensitive proteases in early steps of suppression of the mutation incidence. Thus, fibrinolysis activity was estimated using ^<125>I-fibrin as substrates in cells pretreated with serum factors from pancreatic cancer patients and then irradiated with UV.The factors were obtained by a color-column chromatography method. The fraction sample was obtained which enhance frequencies of ouabain-resistant phenotypic mutation induced by UV.The fraction sample also showed the ability to enhance frequencies of K-ras codon 12 mutation detected by the PCR-based differential dot-blot hybridization analysis. Furthermore the sample enhance the proteases activity induced by UV On the other hand, induction of several genes expression was identified by the RT mRNA differential display method.Therefore, it was suggested that serum factors from pancreatic cancer patients enhance K-ras codon 12 mutation possibly via proteases induction followed by several genes expression.