SIRT1 Regulates RNA Stability to Promote Breast Cancer

项目摘要 每年有60多万女性死于乳腺癌。因此，有一种过度- 骑马需要更好地了解促进乳腺癌的机制，因为这些信息可能 导致了治疗这种疾病的新策略。最近，Cerione实验室发现了一种机制，通过它 高度侵袭性的乳腺癌细胞产生含有促进癌细胞生长的因子的分泌体 生存和转移扩散。具体地说，研究人员表明，NAD+-的表达减少 依赖脱乙酰酶Sirtuin 1(SIRT1)可促进外切体的形成和释放，外切体是一类特殊的 细胞外小泡(EV)，来源于内/溶酶体内的多个囊泡体(MVB) 贩运路径。这种效应是由于RNA结合蛋白IGF2BP2的乙酰化增加所致 结合到编码ATP6V1a的转录本的3‘非翻译区，ATP6V1a是液泡的一个主要催化亚基 ATPase(v-ATPase)，维持溶酶体适当的pH和活性。乙酰化IGF2BP2招募 核酸外切酶，XRN2，它降解ATP6V1A转录本，导致溶酶体活性受损。因此， 原本会在溶酶体中被靶向和降解的MVB被定向到细胞表面，在那里 它们与质膜融合并释放其内容物，即富含独特货物和 可溶性水解酶，进入细胞外空间。分泌组的这些成分被证明是起作用的 共同有力地促进乳腺癌细胞的侵袭性。是否有额外的成绩单 然后测定SIRT1和IGF2BP2对ATP6V1A转录本类似的调控。基座 在进行的全面的RNA测序分析中，鉴定出14个转录本；其中4个 编码的蛋白质可能在乳腺癌进展和/或外切体生物发生中发挥重要作用。 对于本申请的F99阶段，我计划确定这些转录本的稳定性确实受到监管 通过SIRT1和IGF2BP2，并研究它们水平的变化如何影响乳腺癌的进展(目的 1)。除了SIRT1在乳腺癌中发挥的肿瘤抑制作用外，其表达的减少还 还与衰老以及其他疾病密切相关，衰老是患癌症的主要风险因素。在 在这个K00阶段的提案中，我想研究一下衰老和癌症之间的相互作用。一直以来 最近发现，衰老/衰老细胞的积累会导致分泌体的产生，这种分泌体可以 促进癌细胞生长。作为博士后实习生，我的计划是确定电动汽车 来自衰老/衰老细胞的细胞对这种效应有贡献。此外，我还有兴趣探索是否 从癌细胞分泌的EV使细胞能够逃避衰老(目标2)。归根结底， 这项研究旨在了解衰老与癌症之间的关系，以帮助确定潜在的治疗方法 对病人的治疗。

Project Summary Breast cancer is responsible for the deaths of more than 600,000 women each year. Thus, there is an over- riding need to better understand the mechanisms that promote breast cancer, as this information can potentially lead to new strategies to treat the disease. Recently, the Cerione lab discovered a mechanism through which highly aggressive forms of breast cancer cells produce a secretome containing factors that promote cancer cell survival and metastatic spread. Specifically, the researchers showed that the decreased expression of the NAD+- dependent deacetylase Sirtuin 1 (SIRT1) increases the formation and release of exosomes, a specific class of extracellular vesicles (EVs) that are derived from multi-vesicular bodies (MVBs) within the endocytic/lysosomal trafficking pathway. This effect was due to the increased acetylation of the RNA binding protein, IGF2BP2, that binds to the 3' untranslated region of the transcript encoding ATP6V1A, a major catalytic subunit of the vacuolar ATPase (v-ATPase) that maintains the proper pH and activity of lysosomes. Acetylated IGF2BP2 recruits an exonuclease, XRN2, which degrades the ATP6V1A transcript, resulting in impaired lysosomal activity. Thus, MVBs that would otherwise be targeted and degraded in lysosomes are instead directed to the cell surface where they fuse with the plasma membrane and release their contents, i.e., exosomes enriched in unique cargo and soluble hydrolases, into the extracellular space. These components of the secretome were shown to work together to strongly promote the invasiveness of breast cancer cells. Whether there were additional transcripts that were regulated similarly to the ATP6V1A transcripts by SIRT1 and IGF2BP2 were then determined. Based on a comprehensive RNA sequencing analysis performed, fourteen transcripts were identified; four of which encode proteins that potentially play important roles in breast cancer progression and/or exosome biogenesis. For the F99 phase of this application, I plan to establish that the stability of these transcripts is indeed regulated by SIRT1 and IGF2BP2, and to investigate how changes in their levels impact breast cancer progression (Aim 1). In addition to the tumor suppressor role played by SIRT1 in breast cancer, reductions in its expression have also been heavily implicated in aging, a major risk factor for developing cancer, as well as other diseases. In the K00 phase of this proposal, I would like to investigate the interplay between aging and cancer. It has been recently shown that the accumulation of aged/senescent cells results in the production of a secretome that can increase the growth of cancer cells. My plan as a Post-doctoral trainee will be to determine whether the EVs from aged/senescent cells contribute to this effect. Furthermore, I am also interested in exploring whether the EVs secreted from cancer cells enable cells to evade undergoing senescence (Aim 2). Ultimately, the goal of this study is to understand the relationship between aging and cancer to help identify potential therapeutic treatment for patients.