MK-STYX: A Requisite Gatekeeper to Mitochondrial Function and Death

MK-STYX：线粒体功能和死亡必需的看门人

基本信息

批准号：
8465199
负责人：
Jeffrey Paul MacKeigan
金额：
$ 25.27万
依托单位：
VAN ANDEL RESEARCH INSTITUTE
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-07-01 至 2014-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8465199
关键词：
ATP Synthesis Pathway Address Apoptosis Apoptotic Cancer Patient Caspase Cell Death Cell Line Cells Cessation of life Colorectal Colorectal Cancer Complex Coupled Cytotoxic Chemotherapy Data Development Disease Drug Efflux Electron Transport Electrons Gatekeeping Housing Human Genome Kinetics Knowledge Large Intestine Carcinoma Measures Mediating Mitochondria Mitochondrial Proteins Molecular Multidrug Resistance Gene Organelles Oxidative Phosphorylation Patients Pharmaceutical Preparations Phosphoric Monoester Hydrolases Phosphorylation Phosphotransferases Physiological Process Production Proteins Public Health RNA Interference Role Signal Transduction Staging Stimulus Testing Time Xenograft Model base cell type chemotherapeutic agent chemotherapy cohort cytochrome c design efficacy testing efflux pump follow-up in vivo metastatic colorectal neoplastic cell novel overexpression prognostic protein complex response therapeutic target tumor tumor progression

项目摘要

PROJECT SUMMARY/ABSTRACT Chemoresistant metastatic disease presents the most serious threat to cancer patients despite the increased arsenal of targeted therapeutic options available to clinicians. While intense study into late-stage cancer progression has revealed a number of mechanisms that contribute to chemoresistance, little is known about the intracellular signaling mechanisms that desensitize cells to cytotoxic chemotherapy. In an effort to address this knowledge gap, we recently performed a large-scale RNA-interference (RNAi) screen intended to comprehensively identify critical kinases and phosphatases in the human genome that alter or modify tumor cell sensitivity to chemotherapeutic agents. In this RNAi screen, we identified a novel phosphatase, MK-STYX, which potently suppressed the response of tumor cells to a wide variety of chemotherapeutic drugs. Our central hypothesis is that MK-STYX specifically controls mitochondrial function by regulating phosphorylation of the machinery required for ATP synthesis, and thereby serves an essential role in the induction of chemotherapeutic-induced cell death. The objective of this project is to determine how MK-STYX regulates cellular ATP levels, and thus modulates intrinsic apoptosis. We propose the following specific aims to address this hypothesis and to understand its significance in the context of metastatic colorectal carcinoma: (1) Identify the catalytic mechanism of MK-STYX in the mitochondria; (2) Identify the mechanism whereby MK-STYX regulates chemoresistance; (3) Establish the role of MK-STYX in colorectal cancer progression and chemoresistance. Consistent with our central hypothesis, we have shown that loss of MK-STYX increases ATP production. Therefore, we predict that the elevation in cellular ATP due to loss of MK-STYX is sufficient to inhibit apoptosome formation and entry into apoptosis. We have shown that MK-STYX interacts with two additional mitochondrial proteins and we will mechanistically determine the mitochondrial function and the molecular consequences of each of these interactions. We have also shown that loss of MK-STYX expression correlates with colorectal cancer progression. To determine whether loss of MK-STYX mediates chemoresistance in vivo, we will test the efficacy of standard chemotherapies on a colorectal xenograft model using cell lines that demonstrate variable expression of MK-STYX, or have been manipulated to decrease endogenous MK-STYX levels. We will also determine the prognostic significance of MK-STYX protein levels in a cohort of patients with colorectal cancer.

项目概要/摘要尽管耐药性转移性疾病对癌症患者构成最严重的威胁，但临床医生可用的靶向治疗方案库。在对晚期癌症进行深入研究的同时进展揭示了许多导致化疗耐药的机制，但人们对此知之甚少使细胞对细胞毒性化疗不敏感的细胞内信号传导机制。为了努力解决为了弥补这一知识差距，我们最近进行了大规模 RNA 干扰 (RNAi) 筛选，旨在全面鉴定人类基因组中改变或修饰肿瘤的关键激酶和磷酸酶细胞对化疗药物的敏感性。在此 RNAi 筛选中，我们鉴定了一种新型磷酸酶 MK-STYX，它有效抑制肿瘤细胞对多种化疗药物的反应。我们的中心假设是 MK-STYX 通过调节来特异性控制线粒体功能 ATP 合成所需的机制的磷酸化，从而在诱导化疗诱导的细胞死亡。该项目的目标是确定 MK-STYX 如何调节细胞 ATP 水平，从而调节内在细胞凋亡。我们提出以下具体目标解决这一假设并了解其在转移性结直肠癌背景下的意义： (1) 鉴定MK-STYX在线粒体中的催化机制； (2) 确定MK-STYX调节化疗耐药的机制； (3) 确定MK-STYX在结直肠癌进展和化疗耐药中的作用。与我们的中心假设一致，我们已经证明 MK-STYX 的损失会增加 ATP 的产生。因此，我们预测由于 MK-STYX 缺失而引起的细胞 ATP 升高足以抑制凋亡体形成并进入细胞凋亡。我们已经证明 MK-STYX 与另外两个相互作用线粒体蛋白，我们将机械地确定线粒体功能和分子这些相互作用的后果。我们还表明 MK-STYX 表达的缺失与随着结直肠癌的进展。确定 MK-STYX 的缺失是否会介导化疗耐药性体内，我们将使用以下细胞系测试标准化疗对结直肠异种移植模型的功效：表现出 MK-STYX 的可变表达，或已被操纵以减少内源性 MK-STYX 水平。我们还将确定一组患者中 MK-STYX 蛋白水平的预后意义患有结直肠癌。