Hsp60 Regulation of Prostate Cancer Progression

线粒体蛋白质稳态（蛋白质稳态）与癌症有关， 线粒体未折叠蛋白反应（UPRmt）。然而，不知道是否 UPRmt促进肿瘤发生以及是否可以在前列腺中靶向治疗获益 癌（PCa）。这项提案将定义热休克蛋白60（HSP 60），一个关键的组成部分， UPRmt促进侵袭性和抗性PCa。使用基因工程三重敲除（TKO： Pten，Trp 53和Rb 1缺失）肿瘤，我们观察到HSP 60在侵袭性肿瘤中上调。 肿瘤和去势抵抗性前列腺癌（CRPC）的组织中。TCGA 数据分析和我们使用人类PCa特异性TMA的初步数据表明，HSP 60 在Gleason评分较高的前列腺肿瘤中上调。HSP 60沉默诱导的caspase 激活并抑制细胞增殖，而HSP 60过表达促进癌细胞增殖。 生存和增殖。我们提供了第一个证据表明，TKO中HSP 60的基因缺失， 小鼠前列腺增生症模型及HSP 60 D3 G KI对HSP 60寡聚化的抑制作用 肿瘤发生，降低体内肿瘤负荷。我们观察到转录激活因子5 在Gleason刺激下，HSP 60表达和UPRmt活化特异性的ATF 5表达上调， 应激时ATF 5转位至细胞核。使用计算机分析，我们有 鉴定了一种新的UPRmt抑制剂（称为DCEM 1），其在PCa中诱导了强烈的凋亡 细胞并阻断体内肿瘤生长。基于这些发现，我们假设HSP 60- 依赖性线粒体未折叠蛋白反应促进癌细胞适应 前列腺癌的肿瘤进展和治疗耐药性。UPRmt抑制剂的鉴定提供了 PCa患者的替代治疗选择。我们建议测试以下具体目标 这个假设。 目标1.确定转录因子ATF 5在激活线粒体未折叠蛋白中的作用 反应目的2：评估HSP 60寡聚化是否维持功能性线粒体， 抑制细胞凋亡以发展为侵袭性前列腺癌。目标3。探讨HSP 60的临床意义 使用患者来源的异种移植物（PDX）和原代肿瘤细胞进行抑制。 影响：研究结果将提供关于UPRmt如何被激活的基本理解， UPRmt如何减弱持续的线粒体应激，导致侵袭性 和致命的PCa独特的UPRmt抑制剂的鉴定代表了一种新的治疗弱点， 不依赖雄激素调节的前列腺癌。因此，DCEM 1对UPRmt的抑制将具有 对雄激素依赖性和雄激素非依赖性患者的治疗益处更大 CRPC。

Mitochondrial protein homeostasis (proteostasis) has been implicated in cancer and is regulated by mitochondrial unfolded protein response (UPRmt). However, it is unknown whether UPRmt promotes tumorigenesis and whether it could be targeted for therapeutic benefit in prostate cancer (PCa). This proposal will define how heat shock protein 60 (HSP60), a key component of UPRmt, promotes aggressive and resistant PCa. Using genetically-engineered triple knockout (TKO: deletion of Pten, Trp53, and Rb1) tumors, we observed that HSP60 is upregulated in aggressive tumors and castration-resistant prostate cancer (CRPC) compared to WT prostatic tissues. TCGA data analysis and our preliminary data using human PCa-specific TMAs demonstrated that HSP60 is upregulated in prostate tumors with higher Gleason Scores. HSP60-silencing induced caspase activation and inhibited cellular proliferation whereas HSP60 overexpression promoted cancer cell survival and proliferation. We provide the first evidence that, genetic deletion of HSP60 in TKO mouse and inhibition of HSP60 oligomerization by introducing HSP60D3G KI during prostate tumorigenesis, reduced tumor burden in vivo. We observed that activating transcription factor 5 (ATF5), specific for HSP60 expression and UPRmt activation, was upregulated with higher Gleason Scores, and ATF5 was translocated to nucleus during stress. Using in silico analysis, we have identified a novel UPRmt inhibitor (referred to as DCEM1), which induced robust apoptosis in PCa cells and blocked tumor growth in vivo. Based on these findings, we hypothesized that HSP60- dependent mitochondrial unfolded protein response promotes cancer cell adaptation during tumor progression and therapeutic resistance in PCa. Identification of UPRmt inhibitor provides alternative treatment option for patients with PCa. We propose the following Specific Aims to test this hypothesis. Aim 1. Define the role of transcription factor ATF5 in activating mitochondrial unfolded protein response. Aim 2: Evaluate whether HSP60 oligomerization maintains functional mitochondria and inhibits apoptosis to develop aggressive PCa. Aim 3. Explore the clinical relevance of HSP60 inhibition using patient-derived xenografts (PDXs) and primary tumor cells. Impact: The findings will provide fundamental understanding on how UPRmt is activated and how persistent mitochondrial stress is attenuated by UPRmt leading to development of aggressive and lethal PCa. Identification of unique UPRmt inhibitor represents a new therapeutic vulnerability in PCa that does not rely on androgen modulation. Therefore, UPRmt inhibition by DCEM1 will have greater therapeutic benefits for patients with androgen-dependent and androgen-independent CRPC.