QUANTITATIVE STUDIES OF ONCOGENIC TRANSFECTION

产品说明：（申请人的描述）基于啮齿动物细胞的致癌转化的体外测定代表了研究辐射致癌作用的有力研究工具。首先，它们是高度定量的;这对于C3 H、10 T1/2细胞和小鼠胚胎细胞的新鲜外植体都是如此。第二，可以利用胚细胞研究特定基因对辐射诱导转化的影响。第二，可以通过使用来自基因敲除小鼠的胚胎细胞来研究特定基因对辐射诱导转化的影响。基于人类细胞的转化测定不是定量的，但对于寻找参与致癌过程的基因更相关。五个问题将得到解决，所有这些都直接关系到这个计划项目的主要总体目标，即α粒子诱导肿瘤发生的机制的理解。(1)如果一个或多个α粒子穿过细胞质，但没有一个粒子穿透细胞核，那么在这些细胞中是否能诱导转化？(2)转化是否存在“旁观者效应”-即转化是否可以在未被直接击中但与遭受跨核或跨胞质α粒子横断的细胞接触和通信的细胞中诱导？旁观者效应的表现条件是什么？(3)一对α粒子穿过细胞核所引起的转化发生率是否取决于粒子的空间和时间间隔？(4)小鼠胚胎细胞中α粒子诱导转化的发生率是否取决于ATM基因的状态？(5)在被α粒子转化的人类细胞中，特定的基因是否一直不受调控或下调？

DESCRIPTION: (Applicant's Description) In vitro assays for oncogenic transformation based on rodent cells represent a powerful research tools for investigating radiation carcinogenesis. First, they are highly quantitative; this is true for both C3H, 10T1/2 cells and fresh explants of mouse embryo cells. Second, the influence of specific genes on radiation induced transformation can be studied by using embryo cells. Second, the influence of specific genes on radiation induced transformation can be studied by using embryo cells from knock-out mice. Transformation assays based on human cells are not as quantitative, but are more relevant for seeking genes involved in the oncogenic process. Five questions will be addressed, all of which relate directly to the primary overall goal of this program project, namely an understanding of the mechanisms of alpha-particle induced oncogenesis. (1) Can transformation be induced in cells in which the cytoplasm has been traversed by one or more alpha-particles, but none have penetrated the nucleus? (2) Is there a "bystander effect" for transformation- i.e. can transformation can induced in cells which are not directly hit, but are in contact and the communication with cells suffering trans-nuclear or trans- cytoplasmic alpha-particles transversals? What are the conditions for the bystander effect to be manifest? (3) Does the transformation incidence resulting from a pair of alpha-particles through the cell nucleus depend on the spatial and temporal separation of the particles? (4) Does the incidence of transformation induced by alpha-particles in mouse embryo cells depend on the status of the ATM gene? (5) Are specific genes consistently unregulated or down-regulated in human cells transformed by alpha-particles.