DMBA INDUCED SELF REGRESSING TUMORS--ROLE OF H-RAS

这一更新申请解决了结果提出的问题 在目前的时期内获得。 它侧重于回归， DMBA诱导的兔皮肤肿瘤的进展阶段。 在迄今为止获得的结果中，我们发现H-ras被激活， 良性和自我消退的肿瘤（角化棘皮瘤，K.A.s）， 显著低于鳞状细胞癌（SCC）。 这种情况发生在人类和兔子身上。突变的H-ras等位基因是 在KA的成熟和退化阶段表达。 我们现在将 检验H-ras参与KA回归的假设， 分析一系列体外和体内系统。 我们将使用 兔角膜上皮细胞中的瞬时表达测定，稳定 在细胞培养物中的表达和在 转基因兔注射了几种ras构建体， 诱导型角蛋白启动子的控制。 这将与TGF β 1、2和3的研究相结合。 在该系统中的表达，它们可能被ras癌基因诱导， 它与这个系统中的分化相关。 补充，并根据我们的初步结果，我们将研究其他 可能参与SCC进展过程的基因。 与 我们将完成一个显性癌基因的克隆， 我们将分析其分子结构和在皮肤中的作用 肿瘤进展 这种独特系统的分子特征显示了 回归和进步应该是非常有助于解剖 肿瘤发生过程及ras在其中的作用。

This renewal application addresses the questions raised by the results obtained in the present period. It focuses on the regression and progression phases that the DMBA induced skin tumors in rabbits present. In the results obtained so far we have found H-ras to be activated in benign and self-regressing tumors (keratoacanthomas, K.A.s) at a significantly lower frequency than in squamous cell carcinomas (SCCs). This is occurring in humans and rabbits. The mutant H-ras allele is expressed during the mature and regressing phases of the KA. We will now test the hypothesis that H-ras is involved in the KA regression by analyzing an array of in vitro and in vivo systems. We will use transient expression assays in rabbit corneal epithelial cells, stable expression in cell cultures and long term phenotypic experiments in transgenic rabbits injected with several ras constructions under the control of an inducible keratin promoter. This will be combined with the study of the TGF beta 1, 2, and 3 expression in this system, their possible induction by ras oncogenes and its correlation with differentiation in this system. Complementary, and based on our preliminary results, we will study other genes that could be involved in the process of progression to SCC. To that effect we will complete the cloning of a dominant oncogene detected in a rabbit SCC and we will analyze its molecular structure and role in skin tumors progression.. The molecular characterization of this unique system that displays both regression and progression should be very instrumental in dissecting the tumorigenesis process and the role of ras in it.