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.

项目摘要/摘要化学抗性转移性疾病对癌症患者构成了最严重的威胁临床医生可以使用有针对性的治疗方案的武器库。虽然对晚期癌症的深入研究进展揭示了许多有助于化学抗性的机制，对细胞内信号传导机制使细胞对细胞毒性化疗脱敏。为了解决在这一知识差距，我们最近进行了大规模的RNA干扰（RNAi）屏幕，旨在全面识别人类基因组中的临界激酶和磷酸酶改变或改变肿瘤细胞对化学治疗剂的敏感性。在此RNAi屏幕中，我们确定了一种新型的磷酸酶Mk-Styx，这有效抑制了肿瘤细胞对多种化学治疗药物的反应。我们的中心假设是MK-STYX通过调节来专门控制线粒体功能 ATP合成所需的机械的磷酸化，从而在诱导化学治疗诱导的细胞死亡。该项目的目的是确定MK-STYX如何调节细胞ATP水平，从而调节内在凋亡。我们提出以下具体目的解决这一假设，并在转移性结直肠癌的背景下理解其意义：（1）确定线粒体中MK-Styx的催化机制；（2）确定MK-Styx调节化学抗性的机制；（3）确定MK-STYX在结直肠癌进展和化学上的作用。与我们的中心假设一致，我们表明MK-STYX的损失会增加ATP的产生。因此，我们预测，由于MK-STYX的损失，细胞ATP的升高足以抑制凋亡组形成并进入凋亡。我们已经证明MK-STYX与两个附加的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表达的丢失相关结直肠癌的进展。确定MK-Styx的损失是否介导体内，我们将使用细胞系测试标准化学疗法在结直肠异种移植模型上的功效演示MK-STYX的可变表达，或被操纵以减少内源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结直肠癌。