Targeting of Mitochondrial Lon Protease as a Novel Therapy for Glioblastoma

项目总结 胶质母细胞瘤(GBM)是最具侵袭性的原发脑肿瘤，两年生存率不到50%。 在手术切除、放射治疗和化疗后。在第一条线之后，复发几乎是普遍的 治疗，目前还没有被证明可以延长肿瘤复发后生存的治疗方法。因此，有一个 迫切需要更有效的GBM疗法。该项目的总体目标是进一步发展和 验证治疗基底膜的新化疗药物。GBM的抗辐射能力和抗辐射能力 化疗与广泛的缺氧诱导的线粒体依赖性表型改变密切相关 例如糖酵解呼吸，降低了细胞凋亡和广泛侵袭的能力。 线粒体LonP1是一种受三磷酸腺苷刺激的蛋白酶，受缺氧诱导因子-1α的直接上调。LonP1在基因中过度表达 人类恶性胶质瘤及其高表达水平与高胶质瘤分级和 病人存活率很低。因此，通过抑制LonP1蛋白水解酶对线粒体功能的调节可以代表 一种新的治疗基底膜和其他严重依赖缺氧的快速生长的恶性肿瘤的方法 适应。建议的项目是基于我们发表的和从体外获得的初步结果(细胞- 基于)使用siRNA和抑制剂化合物CC4和BT317抑制LonP1的研究以及体内实验 LonP1过表达异种移植模型研究。BT317是一种小分子化合物，能够跨越血液- 并在大脑中实现有希望的浓度。BT317在诱导细胞死亡方面非常有效 在多个胶质瘤系和患者来源的胶质母细胞瘤干细胞培养中，IC50值为60-100微米 (替莫唑胺-FDA批准的主要治疗方法，在正常情况下毒性最小。识别BT317为 这是一种治疗这种普遍致命疾病的潜在新疗法。在这个项目中，我们建议：(1)检查效果 不同患者来源的原代胶质瘤干细胞(GSC)、胶质母细胞瘤中线粒体LonP1基因敲除的研究 细胞系和异种移植模型，(2)识别微环境线索和LonP1诱导的线粒体变化 以及(3)检测药物靶点抑制和抗肿瘤作用的分子机制。 LonP1抑制剂BT317的癌症疗效。这里概述的研究是第一次探索一种非常有前途的 Avenue-线粒体Lon蛋白酶抑制-作为GBM的治疗方法。

PROJECT SUMMARY Glioblastoma (GBM) is the most aggressive primary brain tumor with a two years survival rate of less than 50% following surgical resection, radiation, and chemotherapy. Recurrence is nearly universal after the first-line treatment, and there is currently no therapy proven to prolong survival after tumor recurrence. Thus, there is an urgent need for more effective GBM therapies. The overarching goal of this project is to further develop and validate new chemotherapeutic agents for the treatment of GBM. GBM's resistance to radiation and chemotherapy heavily correlates with extensive hypoxia-induced, mitochondria-dependent phenotypic changes such as glycolytic respiration, decreased the ability to undergo apoptosis and extensive invasiveness. Mitochondrial LonP1 is an ATP-stimulated protease, directly up-regulated by HIF-1α. LonP1 is overexpressed in human malignant gliomas and its elevated expression levels are associated with high glioma tumor grade and poor patient survival. Therefore, regulation of mitochondrial function by inhibiting LonP1 protease could represent a novel approach for GBM and potentially other fast-growing malignancies which heavily depend on hypoxic adaptation. The proposed project is based on our published and preliminary results obtained from in vitro (cell- based) studies with LonP1 inhibition using siRNA and the inhibitor compounds CC4 and BT317 and in vivo LonP1-overexpression xenograft models studies. BT317 is a small molecule compound, able to cross the blood- brain barrier and to achieve promising concentrations in the brain. BT317 is highly effective in inducing cell death in multiple glioma lines and patient-derived glioblastoma stem cell cultures, with an IC50 value of 60-100 µM (temozolomide – the main FDA approved therapy and has minimal toxicity in normal lines. identifying BT317 as a potentially new therapy for this universally fatal disease. In this project, we propose to: (1) examine the effect of mitochondrial LonP1 knockout in distinct patient-derived primary glioma stem-like cells (GSC), glioblastoma cell lines and xenograft models, (2) identify microenvironment cues and LonP1-induced mitochondrial changes that drive GSC invasiveness, and (3) examine the drug-target inhibition and molecular mechanisms for anti- cancer efficacy of the LonP1 inhibitor, BT317. The studies outlined here are the first to explore a very promising avenue – mitochondrial Lon protease inhibition – as a treatment for GBM.