Upstream Regulation and Downstream effectors of c-MYC in Ovarian Cancer

摘要 卵巢癌仍然是女性癌症相关死亡的重要原因，新增约22,440人 预计2017年将有约14,080人死亡。与这项提案的目标一致，有一个 迫切需要确定更好的靶点来治疗晚期和耐药的高级别浆膜腔积液 卵巢癌(HGSOC)是妇科癌症中恶性程度最高、致死率最高的癌症。其中一种可能性是 C-myc是一种癌基因，在包括HGSOC在内的大多数癌症中都高度丰富。我们的研究以前的研究 研究小组使用“癌症基因组图谱”(TCGA)数据门户网站显示HGSOC复发 C-myc表达较高的患者较快。此外，小干扰RNA(SiRNA)介导的c-myc 在卵巢癌小鼠模型中，沉默降低了细胞增殖和肿瘤生长。一起， 这些结果表明，c-myc可能是HGSOC患者的临床相关靶点。尽管 C-myc过表达的分子机制在不同类型的癌症中得到了广泛的研究， 导致c-myc在HGSOC中上调的机制尚未解决。初步结果来自 我们的研究小组表明，c-myc可以在转录后受到HGSOC中microRNAs的调控。 MicroRNAs(MiRNAs)是一种小的非编码RNA，可以潜在地与数千种不同的 信使RNA和抑制蛋白质合成。通过使用生物信息学和分子研究，我们确定了 几个可能调节卵巢癌细胞c-myc表达的miRNAs。最重要的是，短暂的 MiR-98、miR-106a和miR-18a的寡核苷酸miRNA模拟物对这些miRNAs的转染结果表明 显著降低卵巢癌细胞c-myc蛋白水平，抑制细胞增殖。 总之，我们的数据为HGSOC中c-myc调控的新机制提供了洞察力。我们的整体 假设miR-98、miR-106a和miR-18a在转录后调控c-myc的表达。 HGSOC。此外，我们还将检验c-myc调控与细胞存活相关的关键基因的假设。 并与HGSOC细胞的顺铂耐药有关。这一假设将通过追求以下几点来解决 具体目的：(1)鉴定转录后调控HGSOC细胞c-myc表达的microRNAs； (2)研究siRNA介导的c-myc沉默的生物学后果和治疗作用。 与miR-98、miR-106a或miR-18a结合，在HGSOC中模拟；以及(3)阐明c-myc下游 卵巢癌细胞中的效应物。我们在耐药分子机制领域的贡献将 详细阐述了c-myc在HGSOC中的上游调控和下游效应。在……里面 响应“健康差距合作研究中心”的一项主要任务， 这项提议将改善少数民族机构研究人员在基础和翻译方面的参与 癌症研究，并将导致培养当地的研究生和本科生的尖端 癌症研究中的技术和新概念。

ABSTRACT Ovarian cancer remains an important cause of female cancer-related deaths, with approximately 22,440 new cases and about 14,080 deaths predicted for 2017. Consistent with the objective of this proposal, there is an urgent need to identify better targets for therapy against advanced and drug-resistant high-grade serous ovarian cancer (HGSOC), the most malignant and lethal of the gynecological cancers. One such possibility is c-MYC, an oncogene highly abundant in most cancers, including HGSOC. Previous studies by our research team using “The Cancer Genome Atlas” (TCGA) data portal showed that recurrence of HGSOC occurred faster for patients with higher c-MYC expression. In addition, small-interference RNA (siRNA)-mediated c-MYC silencing decreased cell proliferation and reduced tumor growth in an ovarian cancer mouse model. Together, these results suggest that c-MYC could be a clinically relevant target for HGSOC patients. Although the molecular mechanisms of c-MYC overexpression have been extensively studied in different types of cancer, the mechanism leading to c-MYC up-regulation in HGSOC have not been addressed. Preliminary results from our research team indicate that c-MYC could be regulated post-transcriptionally by microRNAs in HGSOC. MicroRNAs (miRNAs) are small non-coding RNAs that can potentially bind to thousands of different messenger RNAs and inhibit protein synthesis. By using bioinformatics and molecular studies we identified several miRNAs that potentially regulate c-MYC expression in ovarian cancer cells. Most important, transient transfection of oligonucleotide miRNA mimics for those miRNAs showed that miR-98, miR-106a and miR-18a significantly decreased the c-MYC protein levels, and reduced the cell proliferation of ovarian cancer cells. Together, our data provide insight into novel mechanisms of c-MYC regulation in HGSOC. Our overall hypothesis is that miR-98, miR-106a and miR-18a post-transcriptionally regulate c-MYC expression in HGSOC. In addition, we will test the hypothesis that c-MYC regulates key genes associated with cell survival and with the cisplatin resistance of HGSOC cells. This hypothesis will be addressed by pursuing the following Specific Aims: (1) identify the microRNAs post-transcriptionally regulating c-MYC expression in HGSOC cells; (2) investigate the biological consequences and therapeutic effects of siRNA-mediated c-MYC silencing in combination with miR-98, miR-106a or miR-18a mimics, in HGSOC; and (3) elucidate the c-MYC downstream effectors in ovarian cancer cells. Our contribution to the field of molecular mechanisms of drug resistance will be a detailed elucidation of the Upstream Regulation and Downstream Effectors of c-MYC in HGSOC. In response to one of the main missions of the “Center for Collaborative Research in Health Disparities” (RCMI), this proposal will improve the participation of researchers in minority institutions in basic and translational cancer research and will result in the training of local graduate and undergraduate students in cutting-edge technology and novel concepts in cancer research.