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涉及先前未被识别的促进致癌转录物快速衰减的细胞机制的新靶点和生物标志物。虽然细胞中的所有蛋白质都是由它们各自的转录本（mrna）产生的，但那些编码促癌蛋白的蛋白质通常在它们的3'非翻译区携带独特的特征。致癌mrna的这些显著特征决定了它们的稳定性和过表达（例如在癌症发展过程中），或者它们的衰变和破坏（例如在正常组织成熟过程中）。我们的初步研究表明，当促进癌症的mRNA与多核糖体相关时，以及蛋白质受到翻译后修饰（如乙酰化）的地方，就会发生破坏。重要的是，这种mRNA破坏机制与多核糖体的区隔化有助于寻找调节这种开关的蛋白质异构体，从而揭示新的癌症治疗靶点。众所周知，表观遗传疗法，如组蛋白去乙酰化酶抑制，可以通过诱导多体蛋白翻译后修饰，迅速诱导ERBB2和其他致癌转录物加速衰变。第一个项目目标是通过质谱（MS）从乳腺癌细胞中分离和鉴定其癌基因转录破坏开关被组蛋白去乙酰化酶抑制激活的多核糖体蛋白异构体。第二个项目目标是利用RNA干扰（RNAi）技术验证候选多核糖体蛋白靶点，这些靶点在调节癌症生长和致癌基因转录物破坏机制中被证明是必不可少的。该项目将生成一个完全表征、验证和优先排序的已知调节癌症生长和癌基因转录稳定性的多核糖体蛋白靶点和生物标志物列表。这份清单将包含最有希望的多核糖体异构体，用于预测和靶向一类全新的癌症治疗方法，通过诱导其转录物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.