A Novel Oncogenic Role for Cdc20 Implications in Adult T Cell Leukemia Treatment

Cdc20 在成人 T 细胞白血病治疗中的新致癌作用

• 批准号: 8791273
• 负责人: Lixin Wan
• 金额: $ 16.97万
• 依托单位: BETH ISRAEL DEACONESS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-06 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8791273
• 关键词: 26S proteasome; Adult T-Cell Leukemia/Lymphoma; Apoptosis; Apoptotic; Award; BCL2 gene; Basic Science; Binding; Bypass; Cancer Patient; Cell Cycle; Cell Line; Cells; Clinic; Clinical; Complex; Cultured Cells; DNA Damage; Data; Development; Diagnosis; Disease; Drug resistance; Exhibits; Fluorouracil; Future; Goals; Head and Neck Cancer; Health; Homeostasis; Human; Human Development; Immune system; In Vitro; Induction of Apoptosis; Intervention; MXI1 gene; Malignant Neoplasms; Mediating; Messenger RNA; Microtubules; Mitosis; Mitotic; Molecular; Molecular and Cellular Biology; Multi-Drug Resistance; Non-Hodgkin' s Lymphoma; Oncogene Proteins; Oncogenic; Outcome; Paclitaxel; Pathway interactions; Patients; Pharmaceutical Preparations; Phenocopy; Physiological; Play; Problem Solving; Protein Family; Proteins; Reagent; Reporting; Repression; Resistance; Role; Scientist; Signal Pathway; Signal Transduction; T-Lymphocyte; Taxes; Therapeutic; Time; Tissues; Training; Translational Research; Ubiquitination; Viral; Virus; Work; Xenograft procedure; base; cancer cell; career; chemotherapeutic agent; chemotherapy; combat; design; in vivo; insight; leukemia; member; metaplastic cell transformation; mimetics; mouse model; novel; novel strategies; overexpression; pro-apoptotic protein; research study; response; skills; tumor; tumorigenesis; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): Overexpression or hyper-activation of Cdc20 has been observed in a variety of human cancers. In adult T-cell leukemia (ATL) patients, the viral oncoprotein Tax promotes cellular transformation in part through activating APCCdc20, a critical M phase driver, to enhance proliferation, and as proposed in this study, to evade apoptosis. The goal of this proposal is to uncover a novel oncogenic role of the APCCdc20 ubiquitin E3 ligase complex in allowing cancer cells to evade chemotherapeutic agents-induced cellular apoptosis, thereby promoting leukemia-genesis and conferring multidrug resistance. My preliminary data showed that the protein levels of the pro-apoptotic protein, Bim, were low in M phase when Cdc20 is most active. Moreover, Bim protein abundance but not mRNA level was significantly elevated in multiple cell lines after depletion of endogenous Cdc20. Further studies revealed that Cdc20 directly binds to Bim and promotes its ubiquitination and subsequent degradation by the 26S proteasome. Strikingly, Bim expression is remarkably low in Human T-cell Lymphotropic Virus type I (HTLV-I)-infected T cell lines with elevated Cdc20 activity, and consistently, these cells are resistant to various anti-mitotic and DNA damage agents. In this proposal, I hypothesize that Cdc20- dependent repression of Bim is critical for ATL cells to evade apoptosis, especially under the challenge of therapeutic drugs. Therefore, inhibiting Cdc20 activity or introducing BH3-mimetic reagents could sensitize ATL cells to conventional chemotherapeutic drugs both in vitro and in vivo. In this proposal, I plan to: 1) Characterize APCCdc20 as an upstream E3 ligase that negatively regulates Bim stability; 2) Determine the physiological role of APCCdc20 activation in suppressing apoptosis; 3) Determine whether targeted inhibition of Cdc20 or introducing BH3-mimetic suppresses the development of ATL or other Cdc20-overexpressing cancer including head and neck cancer in vivo. The long-term goals of my career are to apply the insights of molecular and cellular biology to understand the physiological significance of deregulated proteolytic pathways that are important in the development of human malignancies, and to search for proper druggable targets. This K99/R00 award will provide protected time for me to pursue the novel hypotheses of this proposal, obtain new skill sets to execute experiments and solve problems. In addition, the award will allow me to focus my efforts on independently conducting basic and translational research, and to train future young scientists.

描述(申请人提供)：在多种人类癌症中观察到了CDC20的过度表达或过度激活。在成人T细胞白血病(ATL)患者中，病毒癌蛋白TAX部分通过激活关键的M期驱动因子APCCDC20促进细胞转化，促进增殖，并如本研究所建议的那样，避免细胞凋亡。这项提议的目的是揭示APCCDC20泛素E3连接酶复合体的一种新的致癌作用，使癌细胞能够逃避化疗药物诱导的细胞凋亡，从而促进白血病的发生并产生多药耐药。我的初步数据显示，在CdC20最活跃的M期，促凋亡蛋白Bim的蛋白水平较低。此外，在内源性CdC20耗尽后，多个细胞系的Bim蛋白丰度显著增加，但mRNA水平没有显著提高。进一步的研究表明，Cdc20直接与Bim结合，并促进其泛素化和26S蛋白酶体随后的降解。值得注意的是，在人T细胞淋巴病毒I型(HTLV-I)感染的CDC20活性升高的T细胞系中，Bim的表达显著降低，并且这些细胞一直对各种抗有丝分裂和DNA损伤剂具有耐药性。在这项提议中，我假设依赖于Cdc20的Bim抑制对于ATL细胞逃避凋亡至关重要，特别是在治疗药物的挑战下。因此，无论是在体内还是体外，抑制CDC20活性或引入BH3模拟试剂都可以增强ATL细胞对常规化疗药物的敏感性。在这项提议中，我计划：1)确定APCCDc20是一种上游E3连接酶，负向调节Bim的稳定性；2)确定APCCDc20激活在抑制细胞凋亡中的生理作用；3)确定靶向抑制CDc20或引入BH3类似物是否在体内抑制ATL或其他高表达CDc20的癌症的发展，包括头颈癌。我职业生涯的长期目标是应用分子和细胞生物学的洞察力来理解去调节的蛋白分解途径的生理意义，这些途径在人类恶性肿瘤的发展中很重要，并寻找合适的可用药靶点。K99/R00奖将为我提供受保护的时间，让我探索这项提议的新假设，获得新的技能集来执行实验和解决问题。此外，该奖项将使我能够专注于独立开展基础研究和翻译研究，并培养未来的年轻科学家。