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

描述（由申请人提供）：顺铂是最有效的抗肿瘤药物之一，对多种实体肿瘤表现出临床活性。顺铂的抗肿瘤活性源于顺铂诱导的DNA损伤，DNA损伤进一步引发细胞凋亡。然而，顺铂的有效使用受到肿瘤细胞中顺铂耐药性的限制。损伤的DNA结合蛋白（DDB2）已被报道能够结合紫外线或顺铂诱导的DNA损伤，并被认为与细胞凋亡事件，特别是DNA损伤剂诱导的细胞凋亡有关。然而，DDB2与顺铂诱导的细胞凋亡之间的关系有待验证，其机制有待探索。本文提出的具体假设是，DDB2通过结合DNA损伤传递凋亡信号，调节促凋亡和抗凋亡蛋白，介导顺铂诱导的细胞凋亡；因此，缺乏DDB2会使癌细胞对顺铂产生耐药性。拟开展的工作将利用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，以实现以下具体目标：(1)验证DDB2在顺铂诱导的细胞凋亡中的作用，以及DDB2与Bcl-2在不同癌细胞系和人类肿瘤组织中的关系；(2)明确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与p53在顺铂诱导的细胞凋亡中的关系；(5)在体内检测DDB2在顺铂敏感性和顺铂诱导的细胞凋亡中的作用。本课题的实验重点是DDB2与细胞凋亡的关系。因此，上述特定目的旨在全面评估DDB2对顺铂诱导的细胞凋亡和顺铂耐药发展的调控功能。

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.