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

在胰腺癌细胞中，碱基机构突变是非常容易检测到的。我们已经报道了胰腺癌患者的血清具有增强突变频率的能力。本研究研究了血清对蛋白质和DNA代谢的影响，以阐明其增强活性的机制。我们已经发现，人干扰素在抑制突变发生率的早期阶段诱导抗痛敏感蛋白酶的活性。因此，使用^<125> i -纤维蛋白作为底物，用胰腺癌患者的血清因子预处理细胞，然后用紫外线照射，估计纤维蛋白溶解活性。用彩色柱层析法得到了这些因子。获得了提高紫外诱导的抗瓦巴因表型突变频率的组分样品。通过基于pcr的差分斑点杂交分析，该片段样品还显示出K-ras密码子12突变频率的增强能力。另一方面，通过RT mRNA差异展示法鉴定了几种基因表达的诱导作用。因此，我们认为胰腺癌患者的血清因子可能是通过蛋白酶诱导K-ras密码子12突变，然后是多个基因的表达。

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.