Evaluating unique aspects of quiescent ovarian cancer cell biology for therapeutic targets

大多数卵巢癌（OvCa）患者会发生致命的化疗耐药疾病。阐明机制 卵巢癌化疗耐药性的研究可以确定治疗靶点，以预防或治疗复发的卵巢癌。一 OvCa的化疗耐药机制尚待研究。静止细胞是短暂的 非增殖性的，因此对靶向快速增殖细胞的标准疗法是难治的。过度- 这个项目的假设是，假设是，了解生物学的静态 OvCa癌细胞将确定关键的新治疗靶点，以改善患者的预后。我们有 使用多种新方法来鉴定和表征静止OvCa的转录特征， 细胞这项工作表明，静止OvCa（qOvCa）细胞具有几个独特的特征，包括：（i） 一种独特的静止相关分泌表型（QuASP），可驱动非肿瘤患者的化疗耐药性， 静止的癌细胞，和（ii）泛素-蛋白酶体系统的选择组分的改变的表达 (UPS)包括诱导UBL 7。事实上，我们的初步数据表明，UBL 7的诱导足以 驱动静止细胞表型，包括QuASP的表达。静态的生物信息学分析 OvCa细胞RNAseq数据将SRF/MRTF转录途径鉴定为与细胞周期负相关。 OvCa静止特征。与此一致，SRF/MRTF介导的小分子抑制剂 转录，CCG 081，（i）诱导UBL 7，（ii）驱动细胞进入密集的静止状态，和（iii），表明 由于UPS在静止细胞活力中的关键作用，CCG 081使OvCa细胞对蛋白酶体抑制剂敏感。 基于这些发现，我们提出：SA 1：表征OvCa QuASP。我们假设， 表征QuASP将鉴定与静止相关的关键生物因子。我们将识别QuASP 因子，验证QuASP因子在卵巢癌和其他癌症类型中的表达，并使用 敲低和中和抗体，以评价这些因子在静止OvCa细胞中的功能。 确定UPS和UBL 7在静止癌细胞中的作用。我们假设UPS改变了 有助于静止细胞状态并且对于静止细胞活力是必需的。我们会找出 UPS的组分有助于静止表型，包括QuASP的表达，和 确定蛋白体是否是维持静止OvCa细胞活力所必需的。最后，我们将SA 3： 评价体内靶向蛋白体静止细胞的影响。我们假设， 迫使这些残余细胞进入静止状态，然后通过以下方式消除这些静止细胞： 蛋白酶体抑制将增加治愈率。我们将评估联合CCG 081的治疗潜力 和FDA批准的蛋白体抑制剂作为化疗后的巩固治疗， 静止细胞影响：我们将定义OvCa细胞静止的调节因子，提供治疗靶点 辐射，以改善患者的结果。

Most ovarian cancer (OvCa) patients develop fatal chemotherapy-resistant disease. Elucidating mechanisms of chemoresistance in OvCa may identify therapeutic targets to prevent or treat relapsed OvCa. One understudied mechanism of chemotherapy resistance in OvCa is quiescence. Quiescent cells are transiently non-proliferating and thus refractory to standard therapies which target rapidly proliferating cells. The over- arching hypothesis of this project is that hypothesis is that understanding the biology of quiescent OvCa cancer cells will identify critical new therapeutic targets to improve patient outcomes. We have used multiple novel approaches to identify and characterize the transcriptional signature of quiescent OvCa cells. This work indicates that quiescent OvCa (qOvCa) cells have several unique characteristics including: (i) a unique Quiescence Associated Secretory Phenotype (QuASP) which drives chemotherapy resistance in non- quiescent cancer cells, and (ii) altered expression of select components of the ubiquitin-proteosome system (UPS) including induction of UBL7. Indeed, our preliminary data indicate that induction of UBL7 is sufficient to drive a quiescent cell phenotype, including the expression of the QuASP. Bio-informatic analysis of quiescent OvCa cell RNAseq data identified the SRF/MRTF transcription pathway as being inversely correlated with the OvCa quiescent signature. Consistent with this, a small molecule inhibitor of SRF/MRTF-mediated transcription, CCG081, (i) induces UBL7, (ii) drives cells into a dense quiescent state, and (iii), indicating a critical role for the UPS in quiescent cell viability, CCG081 sensitizes OvCa cells to proteasome inhibitors. Based on these discoveries, we propose: SA 1: To characterize the OvCa QuASP. We hypothesize that, characterizing the QuASP will identify critical biologic factors related to quiescence. We will identify QuASP factors, validate the expression of QuASP factors in ovarian cancer and other cancer types, and use knockdown and neutralizing antibodies to evaluate the function of these factors in quiescent OvCa cells.SA 2: To determine the role of the UPS and UBL7 in quiescent cancer cells. We hypothesize that UPS changes contribute to the quiescent cell state and are essential for quiescent cell viability. We will identify which components of the UPS contribute to the quiescent phenotype, including expression of the QuASP, and determine if the proteosome is essential to maintain quiescent OvCa cell viability. Finally, we will SA 3: Evaluate the impact of targeting the proteosome quiescent cells in vivo. We hypothesize that the ability to pharmacologically force these residual cells into a quiescent state and then eliminate these quiescent cells via proteosome inhibition will increase cure rates. We will evaluate the therapeutic potential of combined CCG081 and FDA-approved proteosome inhibitors as consolidative therapy after chemotherapy to eradicate residual quiescent cells. Impact: We will define the regulators of OvCa cell quiescence, providing therapeutic targets eradiate to improve patient outcomes.