Elucidating the survival mechanisms of rhabdomyosarcoma

项目摘要/摘要 横纹肌肉瘤(RMS)是影响儿童的最常见的软组织癌症。尽管咄咄逼人 联合治疗，近30%被诊断为RMS的儿童将死于转移或 复发。虽然RMS可以发生在身体的任何地方，但所有的病例都由骨骼的表达来定义 肌肉标记。骨骼肌分化由四个DNA结合的生肌调节因子家族控制 因子-MyoD、Myf5、Mygenin和MRF4。普遍认为，RMS肿瘤细胞无法完成 分化是由于这些生肌因子的功能失调所致。我们的实验室先前显示，NF-κB 通过维持肿瘤细胞处于未分化状态来促进RMS。有趣的是，即使NF-κB是 众所周知，RMS在癌症中作为一种生存因素发挥作用，它的独特之处在于不需要NF-κB来 克服应激诱导的细胞凋亡。相反，我们发现MyoD能够补偿NF-κB。 MyoD促进存活的机制是通过保持RMS细胞处于部分分化状态。另一个 我们通过一系列转录组和生物信息学分析阐明的机制表明， MyoD能够抑制细胞凋亡基因。后一种机制的独特之处在于，抑制需要 启动子甲基化。基于这些数据，我假设MyoD作为癌基因在RMS中发挥作用 为了促进细胞存活，这通过1)维持RMS细胞的部分分化状态和2) 通过调节dnmts和启动子高甲基化抑制凋亡基因。第二部分 这项提议将通过两个目的来探讨这一假设。在目标1中，我计划描述PRO- MyoD抑制的凋亡基因及其在RMS中的相关性。我会通过得失来实现这一点 对每个基因进行功能研究，并观察死亡反应表型。我还将探索甲基化 基因启动子对MyoD表达的反应或用调节甲基化的化合物治疗。 在目标2中，我将进行临床前研究，以测试去甲基化药物作为治疗策略的有效性。 以均方根为单位。将利用体外和异种移植肿瘤研究，单独使用去甲基化试剂或在 结合RMS标准的护理药物。我的发现的影响可能不仅仅是展示了一部小说 MyoD在RMS中的作用，但也可能为RMS患者的治疗提供新的治疗策略。

PROJECT SUMMARY/ABSTRACT Rhabdomyosarcoma (RMS) is the most common soft tissue cancers affecting children. Despite aggressive combinatorial therapy, nearly 30% of children diagnosed with RMS will succumb to either metastasis or recurrence. While RMS can occur anywhere in the body, all cases are defined by the expression of skeletal muscle markers. Skeletal muscle differentiation is controlled by a family of four DNA binding myogenic regulatory factors - MyoD, Myf5, myogenin and MRF4. The prevailing belief is that RMS tumor cells are unable to complete differentiation due to the dysfunction of these myogenic factors. Our laboratory previously showed that NF-κB contributes to RMS by maintaining tumor cells in an undifferentiated state. Interestingly, even though NF-κB is widely known to function in cancer as a survival factor, RMS appears to be unique in not needing NF-κB to overcome stress-induced apoptosis. Instead, we find that MyoD is able to compensate for NF-κB. One mechanism by which MyoD promotes survival is by keeping RMS cells in a partially differentiated state. Another mechanism, which we elucidated through a series of transcriptomic and bioinformatic analyses, indicates that MyoD is capable of suppressing apoptotic genes. Unique to this latter mechanism is that suppression requires promoter methylation. Based on these data, I hypothesize that MyoD functions in RMS by acting as an oncogene to promote cell survival, which occurs by 1) maintaining RMS cells in a partially differentiated state and 2) suppressing apoptotic genes through the regulation of DNMTs and promoter hypermethylation. The second part of this hypothesis will be explored in this proposal through two aims. In Aim 1, I plan to characterize the pro- apoptotic genes suppressed by MyoD and their relevance in RMS. I will accomplish this through gain and loss of function studies for each gene and observing the death response phenotype. I will also explore the methylation of the gene promoters in response to MyoD expression or treatment with compounds that regulate methylation. In Aim 2, I will perform preclinical studies to test the efficacy of demethylation agents as a therapeutic strategy in RMS. Both in vitro and xenograft tumor studies will be utilized, using demethylation agents alone or in combination with RMS standard of care drugs. The impact of my findings might not only demonstrate a novel role of MyoD in RMS, but might also advance novel therapeutic strategy for the treatment of RMS patients.