Polyribosome targets mediating mRNA decay for cancer prediction and therapy

描述（由申请人提供）：该R21项目旨在鉴定和表征参与先前未识别的促进致癌转录物快速衰变的细胞机制的新靶标和生物标志物。虽然细胞中的所有蛋白质都是由其各自的转录物（mRNA）产生的，但编码癌症促进蛋白的那些蛋白质通常在其3'非翻译区中携带独特的区别特征。致癌mRNA的这些区别特征允许它们的稳定性和过表达（例如在癌症发展期间），或允许它们的衰变和破坏（例如在正常组织成熟期间）。我们的初步研究表明，当促进癌症的mRNA与多聚核糖体相关时，并且蛋白质受到翻译后修饰如乙酰化时，会发生破坏。重要的是，这种mRNA破坏机制与多聚核糖体的区室化有助于寻找调节这种开关的蛋白质亚型，揭示了新的癌症治疗靶点。已知表观遗传治疗如组蛋白脱乙酰酶抑制通过诱导多核糖体蛋白翻译后修饰快速诱导ERBB 2和其他致癌转录物的加速衰变。第一个项目的目标是通过质谱（MS）分离和鉴定乳腺癌细胞中的多聚核糖体蛋白异构体，这些细胞的癌基因转录破坏开关由组蛋白脱乙酰酶抑制剂激活。第二个项目的目的是验证候选的多核糖体蛋白质靶点，这些靶点被证明在调节癌症生长以及癌基因转录破坏机制方面至关重要，使用RNA干扰（RNAi）技术。该项目将产生一个清单，充分表征，验证和优先的多核糖体蛋白质的目标和生物标志物已知调节癌症的生长和癌基因转录稳定性。该列表将包含最有前途的多核糖体亚型，用于预测和靶向一类全新的癌症治疗药物，这些药物通过诱导转录物衰变来选择性地关闭促癌蛋白。 公共卫生相关性：癌症研究的一个优先问题是需要更多创新的癌症治疗策略及其伴随的预测生物标志物。这一建议的假设是，一个全新的癌症治疗策略可以开发的基础上，靶向关键成分在一个以前未被识别的细胞机制内的多核糖体，调节开关决定癌基因转录稳定性或其破坏。使用一个敏感的和最近开发的多核糖体分析和质谱为基础的方法，我们将发现和确认新的多核糖体蛋白异构体的作用，调节这一开关。这些新的治疗靶点和预测性生物标志物的发现和验证将推动一类创新的癌症治疗药物的开发，这些药物能够通过加速转录物的衰变来选择性地关闭促癌蛋白。

DESCRIPTION (provided by applicant): This R21 project aims to identify and characterize novel targets and biomarkers involved in a previously unrecognized cellular mechanism promoting the rapid decay of oncogenic transcripts. While all proteins in a cell are produced from their respective transcripts (mRNAs), those encoding cancer promoting proteins typically carry unique distinguishing features in their 3' untranslated regions. These distinguishing features of oncogenic mRNAs allow for their stability and overexpression (e.g. during cancer development), or for their decay and destruction (e.g. during normal tissue maturation). Our preliminary research has shown that destruction of the cancer promoting mRNA occurs while it is polyribosome associated and where proteins are subject to post-translational modifications like acetylation. Importantly, compartmentalization of this mRNA destruction machinery to the polyribosome facilitates a search for protein isoforms that regulate this switch, revealing novel cancer therapeutic targets. It is known that epigenetic therapy such as histone deacetylase inhibition rapidly induces accelerated decay of ERBB2 and other oncogenic transcripts, putatively via induction of polysome protein post-translational modifications. The first project aim is to isolate and identify by mass spectrometry (MS) polyribosome protein isoforms from breast cancer cells that have their oncogene transcript destruction switch activated by histone deacetylase inhibition. The second project aim is to validate candidate polyribosome protein targets that are demonstrated to be essential in regulating cancer growth as well as the oncogene transcript destruction mechanism, using the technique of RNA interference (RNAi). This project will generate a list of fully characterized, validated, and prioritized polyribosome protein targets and biomarkers known to regulate cancer growth and oncogene transcript stability. This list will contain the most promising polyribosome isoforms for prediction and targeting of an entirely new class of cancer therapeutics that selectively turn off cancer-promoting proteins by inducing their transcript decay. PUBLIC HEALTH RELEVANCE: A priority issue for cancer research is the need for more innovative cancer treatment strategies and their companion predictive biomarkers. The hypothesis underlying this proposal is that an entirely new cancer treatment strategy can be developed based on targeting key components in a previously unrecognized cellular mechanism within polyribosomes that regulates a switch determining either oncogene transcript stability or its destruction. Using a sensitive and recently developed polysome profiling and mass spectrometry-based approach, we will discover and confirm the role of novel polysome protein isoforms that regulate this switch. The discovery and validation of these novel therapeutic targets and predictive biomarkers will drive the development of an innovative class of cancer therapeutics capable of selectively turning off cancer-promoting proteins by accelerating their transcript decay.