Role of DDB2 in chemotherapeutic agents-induced apoptosis and platinum resistance

描述(申请人提供)：顺铂是最有效的抗肿瘤药物之一，它对多种实体肿瘤显示出临床活性。顺铂的抗肿瘤活性来源于顺铂诱导的DNA损伤，DNA损伤进一步触发细胞凋亡。然而，顺铂的有效利用受到癌细胞对顺铂耐药性的发展的限制。损伤DNA结合蛋白(DDB2)能与紫外线或顺铂诱导的DNA损伤结合，并与细胞的凋亡事件，特别是DNA损伤剂诱导的细胞凋亡密切相关。然而，DDB2与顺铂诱导的细胞凋亡之间的关系尚需验证，其机制还需进一步探讨。该方案提出的具体假设是，DDB2DNA损伤通过结合DNA损伤传递凋亡信号，调节促凋亡和抗凋亡蛋白，从而介导顺铂诱导的细胞凋亡；因此，DDB2缺失使癌细胞对顺铂产生耐药。这项拟议的工作将利用PI实验室已建立和正在进行的相关生化、生物物理、免疫学、细胞和分子技术来解决以下具体目标：(1)验证DDB2在顺铂诱导的细胞凋亡中的作用以及在不同癌细胞株和人类肿瘤组织中的关系；(2)确定DDB2识别顺铂诱导的DNA损伤在触发细胞凋亡中的作用；(3)阐明DDB2下调Bcl-2水平的机制；(4)揭示DDB2和P53在顺铂诱导的细胞凋亡中的关系；(5)检测DDB2DNA在体内对顺铂的敏感性及顺铂诱导的细胞凋亡中的作用。这项建议的实验重点是DDB2微卫星与细胞凋亡的关系。因此，上述特定的目的旨在提供一个全面的评估DDB2对顺铂诱导的细胞凋亡和顺铂耐药发展的调节功能。

DESCRIPTION (provided by applicant): Cisplatin is one of the most potent anti-tumor agents, which displays clinical activity against a wide variety of solid tumors. The anti-neoplastic activity of cisplatin results from cisplatin- induced DNA damage, which further triggers cellular apoptosis. However, the effective use of cisplatin is limited by the development of cisplatin resistance in cancer cells. Damaged DNA binding protein (DDB2) has been reported to be able to bind UV- or cisplatin-induced DNA damage, and believed to have a correlation with the apoptotic event, especially the apoptosis induced by DNA damaging agents. However, the relationship between DDB2 and cisplatin- induced apoptosis needs to be validated and the mechanism needs to be explored. The specific hypothesis addressed in this proposal is that DDB2 mediates cisplatin-induced apoptosis through binding DNA damage to relay the apoptotic signals, and regulating pro- and anti-apoptotic proteins; as a result, DDB2 deficiency confers cancer cells resistance to cisplatin. The proposed work will utilize relevant biochemical, biophysical, immunological, cellular and molecular technologies mostly established and ongoing in the PI's laboratory to address the following specific aims: (1) To validate the role of DDB2 in cisplatin-induced apoptosis and the relationship between DDB2 and Bcl-2 in varying cancer cell lines and human tumor tissues; (2) To define the role of DDB2 recognition of cisplatin-induced DNA damage in triggering apoptosis; (3) To delineate the mechanism through which DDB2 down-regulates Bcl-2 level; (4) To reveal the relationship between DDB2 and p53 in the cisplatin-induced apoptosis; (5) To test the role of DDB2 in cisplatin sensitivity and cisplatin- induced apoptosis in vivo. The experimental focus of this proposal is on the relationship between DDB2 and apoptosis. Thus, the above-mentioned specific aims are designed to provide a comprehensive assessment of the regulatory function of DDB2 on cisplatin-induced apoptosis and the development of cisplatin resistance.