Targeting glioma stem cells by perturbation of telomere maintenance mechanisms

描述(申请人提供)：这项拟议的研究旨在探索通过干扰胶质瘤干细胞的端粒维持机制来治疗恶性胶质瘤的新的治疗机会。恶性胶质瘤高度耐药的主要原因是胶质瘤干细胞的存在，它具有取之不尽、用之不竭的自我更新和增殖能力。我建议通过抑制端粒酶来靶向GSC，因为GSC比体细胞和其他非GSC肿瘤细胞具有更高的端粒酶活性水平。对于目标1，我将用三个独立的模型系统来探索GSCs对端粒酶抑制的反应。我还将测试抗端粒酶是否会在联合治疗方案中使常规放射治疗和化疗变得敏感。我以前的研究表明，反义端粒酶将通过ALT(Alternative Lengthenging Of Telmer)机制导致耐药，因此，在目标2中，我将生成并鉴定依赖ALT机制的GSC，并探索针对ALT弱点的可能性，以防止对抗端粒酶治疗的耐药。更多的证据表明染色质重塑因子在端粒调控中的重要作用，因此在目标3中，我将研究端粒酶+和ALT+胶质瘤干细胞的端粒染色质重塑的机制。从这一目的获得的信息将有助于我们理解GSC背景下ALT机制的性质，并为靶向ALT+GSC提供新的治疗机会。这项拟议的研究将帮助我形成一个强大的研究计划，在这个计划下，我将在一家学术/医学研究机构担任一个独立的教员职位。为此，我的眼前目标是继续磨练我在老鼠遗传学、端粒生物学和干细胞生物学方面的技术技能，并扩大我在肿瘤基因组学、生物统计学和翻译生物学方面的技能。在我的职业发展方面，我将致力于提高我在实验室管理、指导博士后和学生、科学写作和演示以及寻求合作等方面的技能，因为这些技能都是我获得教员职位并作为PI成功的必备技能。安德森癌症中心(MDACC)和罗纳德·德皮尼奥实验室为我实现这些目标提供了一个极好的培训环境。即使DePinho博士现在是MDACC的总裁，他仍然承诺将2.5%的精力投入到我的培训和职业发展中。我亦成立了一个特别谘询委员会，成员包括黄绵杰博士、容伟群博士和陈俊杰博士。他们不仅将为我提议的研究提供技术支持，而且还将指导我寻找教员职位，并作为一名独立调查员取得成功。在K99/R00培训基金的帮助下，我将有一个良好的开端来实现我的长期目标，即作为学术/医学研究机构的实验室负责人，继续探索癌症生物学中的基本和翻译问题，包括端粒生物学和癌症干细胞生物学，并通过与其他科学家、医生和制药公司的合作，作为团队成员为开发新型癌症疗法做出贡献。

DESCRIPTION (provided by applicant): The proposed study is to explore novel therapeutic opportunities to cure malignant gliomas by perturbing telomere maintenance mechanisms in glioma stem cells. Malignant gliomas are highly resistant to treatment largely due to the existence of glioma stem cells (GSCs), which possess inexhaustible ability to self-renew and proliferate. I propose to target GSCs by inhibiting telomerase because GSCs have higher level of telomerase activity than somatic cells and other non-GSC tumor cells. With Aim 1, I will explore GSCs' response to telomerase inhibition with three independent model systems. I will also test whether anti-telomerase sensitizes conventional radiation therapy and chemotherapy in combinatorial therapy regimens. My previous study showed that anti-telomerase will lead to resistance through ALT (Alternative Lengthening of Telomeres) mechanisms, so in Aim 2 I will generate and characterize GSCs that rely on ALT mechanisms and will explore the possibility to target the weakness of ALT in order to prevent the resistance in response to anti-telomerase therapy. More evidence is pointing to the important function of chromatin remodeling factors in the regulation of telomeres, so in Aim 3, I will investigate the mechanisms of telomeric chromatin remodeling in telomerase+ and ALT+ glioma stem cells. The information obtained from this aim will help us understand the natures of ALT mechanisms in the GSC context and provide new therapeutic opportunities to target ALT+ GSCs. This proposed study will help me to form a strong research program, with which I will launch an independent faculty position in an academic/medical research institution. To that end, my immediate goals are to continue sharpening my technical skills in mouse genetics, telomere biology and stem cell biology and expanding my skills in oncogenomics, biostatistics and translational biology. In terms of my career development, I will be devoted to improve my skills on managing lab, mentoring postdocs and students, scientific writing and presentation, and seeking for collaborations, among others, because these skills are all essential for me to land a faculty position and succeed as a PI. MD Anderson Cancer Center (MDACC) and the Ronald DePinho laboratory provide an excellent training environment for me to achieve these goals. Even though Dr. DePinho is President of MDACC now, he still promises to devote 2.5% effort to my training and career development. I have also formed an extraordinary advisory committee composed of Dr. Mien-Chie Huang, Dr. Wai-Kwan Yung and Dr. Junjie Chen. They will not only provide me technical support for my proposed study, but also guide me to look for a faculty position and succeed as an independent investigator. With the help of K99/R00 training grant, I will have a good start to achieve my long term goals, which are to continue exploring basic and translational problems in cancer biology, including telomere biology and cancer stem cell biology, as a lab head in an academic/medical research institute and to contribute in developing novel cancer therapies as a team player by collaborating with other scientists, physicians and pharmaceutical companies.