IDENTIFICATION OF ANTICANCER DRUG TARGETS USING YEAST

越来越多的证据表明，遗传不稳定性是许多癌症，特别是实体瘤的发病机制的基础。 最近的研究表明，发生在大多数散发性结直肠癌中的染色体不稳定性（CIN）可能是由有丝分裂纺锤体检查点基因突变引起的。 微卫星不稳定性（MIN）发生在大多数遗传性非息肉病性结直肠癌（HNPCCs）中，是由错配修复基因突变引起的。 引起CIN和MIN的突变增加了肿瘤异质性，这被认为会推动肿瘤进展并使抗癌药物治疗复杂化。 然而，由于这些突变也将肿瘤细胞与正常细胞区分开来，它们可能为识别抗癌药物靶标提供关键途径。色葡萄酿酒酵母基因BUB 1和MSH 2与已知引起人类肿瘤中CIN和MIN的基因同源。 酵母同源基因在癌症发病机制中的基本作用的存在，应允许使用合成致死分析的抗癌药物靶点的鉴定。 合成致死分析是酵母遗传学家用于鉴定基因的技术，当突变时，在先前表征的基因突变的背景下导致细胞致死。 已知在BUB 1和MSH 2中具有突变的酵母是可行的。 使用合成致死分析，可以鉴定当突变时导致BUB 1或MSH 2突变的合成致死的基因。 由引起合成致死性的基因的人类同源物编码的蛋白质代表了具有hBUB 1或hMSH 2突变的癌症的潜在药物靶标。具体目的是：1）通过合成致死分析鉴定S.缺乏BUB 1的酿酒酵母菌株。 对BUB 1-ADE 3质粒拯救的bub 1 ade 2 ade 3菌株进行诱变，并在非选择性培养基上筛选非扇形菌落。 将确认bub 1突变基因的合成致死性，并通过互补克隆野生型版本。 2)目的通过合成致死分析来鉴定S.缺乏MSH 2的酿酒酵母菌株。 将对MSH 2进行特定目标1中描述的BUB 1分析。

There is increasing evidence that genetic instability underlies the pathogenesis of many cancers, particularly solid tumors. It was recently demonstrated that chromosomal instability (CIN), which occurs in most sporadic colorectal cancers, can be caused by mutations in mitotic-spindle-checkpoint genes. Microsatellite instability (MIN) occurs in most hereditary non-polyposis colorectal cancers (HNPCCs), and is caused by mutation in mismatch-repair genes. Mutations causing CIN and MIN increase tumor heterogeneity, which is thought to drive tumor progression and complicate anticancer drug therapies. However, because these mutations also distinguish tumor cells from normal cells, they may provide critical avenues for the identification of anticancer drug targets. The S. cerevisiae genes BUB1 and MSH2 are homologous to genes known to cause CIN and MIN in human tumors. The existence of yeast homologs of genes with fundamental roles in cancer pathogenesis should allow the identification of anticancer drug targets using synthetic lethal analysis. Synthetic lethal analysis is a technique used by yeast geneticists to identify genes that, when mutated, result in lethality to the cell in the context of mutations in previously characterized genes. Yeast with mutations in BUB1 and MSH2 are known to be viable. Using synthetic lethal analysis, one can identify genes that, when mutated, result in synthetic lethality with BUB1 or MSH2 mutations. The proteins encoded by the human homologs of genes that bring about synthetic lethality represent potential drug targets for cancers with mutations in hBUB1 or hMSH2. The Specific Aims are: 1) To identify genes by synthetic lethal analysis that are required for the viability of S. cerevisiae strains lacking BUB1. A bub1 ade2 ade3 strain rescued by a BUB1- ADE3 plasmid will be mutagenized and screened for non-sectored colonies on a non-selective medium. Synthetic lethality of mutated genes with bub1 will be confirmed and the wild-type versions will be cloned by complementation. 2) To identify genes by synthetic lethal analysis that are required for the viability of S. cerevisiae strains lacking MSH2. The analysis described in Specific Aim 1, for BUB1, will be performed for MSH2.