Targeting sfRon-S6K1 signaling and mitotic kinesin Eg5 in ovarian cancer: a novel synergistic treatment strategy

项目摘要 卵巢癌仍然是全国所有妇科恶性肿瘤中最致命的。不幸的是，目前的卵巢 癌症治疗在超过85%的患者中导致化学抗性和快速肿瘤复发。的 这里概述的项目是治疗干预急需的新机会。我们以前的 已发表和正在进行的工作表明，短型罗恩（sf罗恩），全长罗恩的截短同种型， （flRon）受体酪氨酸激酶，可以驱动卵巢癌的发展和进展。之前，我们展示了 sfRon优先通过PI 3 K通路发出信号，关键的sfRon效应子S6 K1对于 肿瘤促进作用。我们的初步发现揭示了sfRon-S6 K1信号转导在诱导细胞凋亡中的新功能。 细胞周期的有丝分裂进程。这些数据导致了药物筛选研究，表明sfRon的抑制作用 或S6 K1（分别通过BMS 777608或AD 80）使卵巢癌细胞特别易受有丝分裂的影响。 驱动蛋白Eg 5抑制剂Ispinesib.我们假设协同联合治疗同时 阻断sfRon或S6 K1和有丝分裂驱动蛋白可以证明是一种有效的精确治疗晚期乳腺癌的方法。 卵巢癌为了验证这一假设，我们提出了两个具体的目标：（1）我们将确定的机制， 其中sfRon促进细胞周期的有丝分裂进程。我们将测试sfRon和/或S6 K1是否耗尽 通过遗传和药理学方法的信号传导影响细胞增殖、细胞周期分布和有丝分裂。 关键有丝分裂调节因子如Aurora B和/或Plk 1的进展或正常功能。此外，我们假设 S6 K1的缺失有助于卵巢癌细胞的有丝分裂滑移，使其对伊匹尼塞敏感。 为了验证这一点，我们将比较sfRon、S6 K1和有丝分裂驱动蛋白抑制剂作为单一疗法或联合应用的效果。 组合并确定药物诱导的细胞命运，包括有丝分裂停滞、有丝分裂滑移和细胞死亡。 (2)我们将确定是否协同联合治疗阻断sfRon-S6 K1信号传导和有丝分裂驱动蛋白导致 使用临床相关的患者来源的异种移植物（PDX）的有效和持续的抗肿瘤功效。我们将 使用未经化疗的PDX，并确定sfRon协同通路的抑制是否会导致更多的 比标准化疗更持久的抗肿瘤反应。在复发性疾病的情况下，我们将使用我们的 化疗耐药的PDX模型，并研究联合治疗是否是一种有效的治疗方案， 复发性卵巢肿瘤，目前有非常有限的治疗选择。这项提案将扩大我们的 理解sfRon和/或S6 K1调节细胞周期的有丝分裂进程的机制。它 也将为为什么sfRon-S6 K1抑制使卵巢癌细胞特别脆弱提供新的见解 有丝分裂驱动蛋白抑制剂。从长远来看，该项目可以提供一种新的精确治疗方法， 即使是对化疗耐药的卵巢肿瘤也有临床意义和持续的抗肿瘤反应。

PROJECT SUMMARY Ovarian cancer remains the deadliest of all gynecologic malignancies nationwide. Unfortunately, current ovarian cancer treatment leads to chemoresistance and a rapid tumor recurrence in more than 85% of patients. The project outlined here represents a much needed new opportunity for therapeutic intervention. Our previous published and ongoing work, has revealed that short-form Ron (sfRon), a truncated isoform of the full-length Ron (flRon) receptor tyrosine kinase, can drive ovarian cancer development and progression. Previously, we showed that sfRon preferentially signals through the PI3K pathway, and that the key sfRon effector S6K1 is crucial for tumor promoting effects. Our preliminary findings revealed a novel function of sfRon-S6K1 signaling in inducing mitotic progression of the cell cycle. These data led to drug screening studies showing that the inhibition of sfRon or S6K1 (by BMS777608 or AD80, respectively) renders ovarian cancer cells particularly vulnerable to mitotic kinesin Eg5 inhibitor Ispinesib. We hypothesize that a synergistic combination therapy simultaneously blocking sfRon or S6K1 and mitotic kinesins could prove an effective precision treatment for advanced ovarian cancer. To test this hypothesis, we propose two specific aims: (1) We will determine the mechanism by which sfRon promotes the mitotic progression of cell cycle. We will test if depletion of sfRon and/or S6K1 signaling by genetic and pharmacological approaches affects cell proliferation, cell cycle distribution, and mitotic progression or proper function of critical mitotic regulators such as Aurora B and/or Plk1. Further, we hypothesize that the depletion of S6K1 contributes to mitotic slippage of ovarian cancer cells sensitizing them to Ispinesib. To test that, we will compare the effects of sfRon, S6K1, and mitotic kinesin inhibitors as monotherapy or in combination and determine the drug-induced cell fate including mitotic arrest, mitotic slippage, and cell death. (2) We will determine if synergistic combination therapy blocking sfRon-S6K1 signaling and mitotic kinesins leads to a potent and sustained antitumor efficacy using clinically relevant patient-derived xenografts (PDXs). We will use chemotherapy naïve PDXs and determine if the inhibition of sfRon synergistic pathways results in a more sustained anti-tumor response than standard chemotherapy. In recurrent disease setting, we will use our chemoresistant PDX models and investigate if the combination therapy is an effective treatment regimen for recurrent ovarian tumors that currently have very limited treatment options. This proposal will expand our understanding of the mechanism by which sfRon and/or S6K1 regulates the mitotic progression of cell cycle. It will also provide new insight into why sfRon-S6K1 inhibition renders ovarian cancer cells particularly vulnerable to mitotic kinesin inhibitors. In the long-term, this project could offer a new precision therapy designed to achieve a clinically meaningful and sustained anti-tumor response to even chemoresistant ovarian tumors.