HUMAN MUTATOR GENES AND THERAPEUTIC EFFICACY IN COLORECTAL CANCER

遗传性非息肉病性结直肠癌（HNPCC）占结直肠癌的6-10%，主要与人类错配修复（MMR）基因hMSH 2和hMLH 1的种系改变相关。其他三个MMR基因[hMSH 3，hMSH 6和hPMS 2]已在体外证实了MMR功能，但在HNPCC中很少改变。除了HNPCC，平均10-20%的所有类型的散发性肿瘤表现出微卫星不稳定性（MCI），这是人类MMR缺陷的标志。人类MMR基因与从细菌到人类的高度保守的MMR蛋白家族相关。我们已经开发了国际公认的MMR途径导致肿瘤发生的程序。此外，我们还发现了一种新的信号传导机制，用于MMR基因直接修复和/或凋亡。我们建议：1.）确定已知的MMR基因（Hmsh 2、Hmsh 3、MSH 6、hMLH 1和hPMS 2）中的哪一个被改变分析，随后进行直接外显子测序、组织荧光原位杂交（FISH）和开发其他新的突变检测方案; II.）通过以下方式确定与非整倍体途径肿瘤相比，MSI肿瘤中MMR途径基因的组合中的哪些基因改变：a.）p53、K-ras、TGFRII、IGF-RII、BAX、Tcf-4、β-catinin和染色体18 q洛的序列;和B）APC、FHIT、p53、p21、Bcl 2、PLA 2g 2s的IHC; III.）确定暴露于顺铂、MNNG、CPT-11、5-氟尿嘧啶和电离辐射对遗传定义的MMR缺陷细胞的细胞后果，以用作治疗功效的预测因子;以及IV.）确定与MMR信号传导至下游效应物相关的功能后果/过程，导致体外和体内DNA修复和/或凋亡。这些研究是直截了当的，应该提供一个关于结直肠肿瘤中人类MMR基因功能改变的数据库，以及MMR通路肿瘤诊断和治疗效果的坚实基础。

Hereditary Non-Polyposis Colorectal (HNPCC) accounts for 6-10% of colorectal cancers and is primarily associated with germline alterations in the human mismatch repair (MMR) genes hMSH2 and hMLH1. Three other MMR genes [hMSH3, hMSH6 and hPMS2] have demonstrated MMR functions in vitro but are rarely altered in HNPCC. In addition to HNPCC, an average of 10-20% of sporadic tumors of all types manifest microsatellite instability (MCI) that is a hallmark of a human MMR defect. The human MMR genes are related to highly conserved families of MMR proteins identified from bacteria to man. We have developed the internationally recognized procedure(s) for the MMR-pathway leading to tumorigenesis. Moreover, we have discovered a novel signaling mechanism used by the MMR genes to direct repair and/or apoptosis. We propose to: 1.) determine which of the known MMR genes (Hmsh2, Hmsh3, MSH6, hMLH1 and hPMS2) are altered analysis, followed by direct exon sequencing, tissue Fluorescent in situ hybridization (FISH) and the development of other novel mutational detection schemes; II.) determine which of a combination of MMR-pathway genes are altered in MSI tumors in comparison to Aneuploid-Pathway tumors by: a.) sequence for p53, K-ras, TGFRII, IGF-RII, BAX, Tcf-4, beta-catinin, and chromosome 18q LOH; and b) IHC for APC, FHIT, p53, p21, Bcl2, PLA2g2s; III.) det4ermine the cellular consequences of exposures to cisplatinum, MNNG, CPT-11, 5-Fluorouracil and ionization radiation on genetically defined MMR defective cell, to be used as a predictor of therapeutic efficacy; and IV.) determine the functional consequences/processes associated with MMR signaling to downstream effectors leading to DNA repair and/or apoptosis in vitro and in vivo. These studies are straight-forward and should provide a database on the functional alterations of the human MMR genes if colorectal tumors as well as a firm foundation for diagnostic and therapeutic efficacy of MMR-Pathway tumors.