A transcription-independent role of HSF1 in tumorigenesis via suppression of AMPK

项目摘要 目前迫切需要开发新的致癌治疗选择。这个目标 一项提议是通过对驱动分子通路的新认识来帮助满足这一需求。 肿瘤发生最近发表的数据揭示了热休克因子1的促癌活性 HSF 1是热休克反应的主要调节因子，表明AMP活化蛋白 AMPK磷酸化HSF1的S121，使其失活，从而破坏恶性肿瘤。 HSF1激酶是否影响AMPK还有待研究。初步数据表明 HSF 1与AMPK物理相互作用并抑制AMPK，而不依赖于HSF 1的转录活性 在稳定状态下。HSF 1的基因缺失抑制细胞脂肪生成，胆固醇合成， 蛋白质胆固醇化（对靶蛋白的稳定性和活性很重要）和脂肪量 在混合背景小鼠中通过AMPK。HSF1的过表达促进脂肪生成， 表型和肿瘤生长。这些结果表明，HSF 1的转录独立， 抑制AMPK促进肿瘤生长的脂肪生成表型。拟议项目涉及 这一假设通过追求两个具体目标。目的1：阐明 HSF1介导的AMPK抑制。首先，将使用HSF 1肽的高分辨率文库 在体外和体内模型中研究AMPK抑制。第二，将使用生物物理方法 以确定HSF 1对AMPK构象的影响。目的2：检验HSF 1 支持肿瘤生长中的脂质生物合成。首先，HSF1是如何调节AMPK介导的 将测定脂肪生成、胆固醇合成和蛋白质胆固醇化。二是 将在AMPK抑制的近交系小鼠中研究其机制。第三，转录 HSF1及其相关AMPK调节的脂质和胆固醇代谢的独立活性 将在人黑素瘤异种移植模型中进行研究。这一建议意义重大，因为它将 提供了一个更深入的了解蛋白质稳态在肿瘤进展，研究一种新的 用于癌症治疗的治疗靶点，并鉴定基因表达特征， 临床进展和结果。该项目在概念和技术上都具有创新性，因为它将： i）检查HSF 1作为AMPK的新型抑制剂的作用，ii）研究蛋白质胆固醇化 iii）开发内源性HSF 1作为癌症的新的预后指标 患者生存率。该提案将提供一个垫脚石，使候选人能够建立 独立的研究生涯，并最终成为致癌领域的领导者， 有助于突破性的发现，从而改善治疗策略。

Project Summary There is an urgent need to develop new therapeutic options for carcinogenesis. The goal of this proposal is to help fulfill this need by shedding new light on the molecular pathways driving tumorigenesis. Recently published data reveals pro-oncogenic activity of heat shock factor 1 (HSF1), the master regulator of the heat shock response, and indicate that AMP-activated protein kinase (AMPK) phosphorylates S121 of HSF1, inactivating it and thereby disrupting malignancy. Whether HSF1 reciprocally impacts AMPK has yet to be explored. Preliminary data indicate that HSF1 physically interacts with and inhibits AMPK independently of HSF1 transcriptional activity at steady state. Genetic deletion of HSF1 suppresses cellular lipogenesis, cholesterol synthesis, protein cholesteroylation (important for the stability and activity of the target protein), and fat mass in mixed background mice through AMPK. Overexpression of HSF1 promotes a lipogenic phenotype and tumor growth. These results suggest that HSF1 transcriptionally independently inhibits AMPK to promote lipogenic phenotype of tumor growth. The proposed project addresses this hypothesis by pursuing two Specific Aims. Aim 1: To elucidate the detailed mechanism of HSF1-mediated AMPK suppression. First, a high-resolution library of HSF1 peptides will be used to study AMPK inhibition in in vitro and in vivo models. Second, a biophysical method will be used to determine the impact of HSF1 on AMPK conformation. Aim 2: To test the hypothesis that HSF1 supports lipid biosynthesis in tumor growth. First, how exactly HSF1 regulates AMPK-mediated lipogenesis, cholesterol synthesis, and protein cholesteroylation will be determined. Second, the mechanism will be studied in inbred mice with AMPK suppression. Third, the transcriptionally independent activity of HSF1 and its associated AMPK-regulated lipid and cholesterol metabolism will be studied in a human melanoma xenograft model. This proposal is significant because it will provide a deeper understanding of proteostasis in tumor progression, investigate a novel therapeutic target for cancer treatment, and identify a gene expression signature that informs clinical progression and outcomes. The project is conceptually and technically innovative as it will: i) examine the role of HSF1 as a novel inhibitor for AMPK, ii) investigate protein cholesteroylation by HSF1 and AMPK, and iii) develop endogenous HSF1 as a novel prognostic indicator for cancer patient survival. The proposal will provide a stepping stone to enable the candidate to establish an independent research career and ultimately become a leader in the field of carcinogenesis, contributing to breakthrough discoveries that lead to improved treatment strategies.