Adaptive resistance to HIF1a inhibition in hypoxia

项目摘要 晚期和转移性癌症患者的治疗选择有限，面临严峻的后果。的确有 迫切需要新颖有效的治疗方法。缺氧是实体瘤的普遍病理特征。 低氧肿瘤细胞主要通过低氧活动获得转移和致命的表型- 诱导因子1α(HIF1α)。因此，HIF1α被认为是一个很有前途的治疗靶点。到目前为止， 虽然在临床前研究中已经发现并验证了几种HIF1α抑制剂，但临床上 这些代理人的翻译就不那么成功了。在临床前模型中看到的强大的抗肿瘤作用 在临床试验中没有观察到。临床疗效不佳的原因尚不清楚。因此，从长远来看， 这项建议的目标是了解肿瘤细胞如何适应性反应和对 HIF1α抑制，并利用这一知识将HIF1α抑制剂转化为临床有效和 可持续的治疗。在初步研究中，我们使用稳定的shRNA特异性地抑制了多个 人类肿瘤细胞系。我们发现，尽管肿瘤细胞最初对黄曲霉毒素的抗肿瘤活性很敏感 HIF1α抑制后，它们在体外缺氧和体内移植瘤中迅速产生抵抗力 HIF1α仍受抑制。从机制上讲，我们观察到肿瘤细胞对hif1α有适应性反应。 通过增加致癌蛋白ID1在低氧中的稳定性来抑制，我们发现沉默ID1 恢复了对HIF1α抑制的敏感性，而过度表达ID1则赋予了抗性。在这项提案中，我们将 验证HIF1α抑制通过代偿性稳定化诱导适应性抵抗的假说 低氧中的致癌蛋白Id1，它反过来支持HIF1α抑制的低氧生长 肿瘤。我们进一步假设，沉默ID1或ID1介导的致癌通路将阻断 并增强抑制HIF1α的抗肿瘤效果。我们将使用分子生物学和 临床前动物模型在三个特定目标上检验这一假说。目标1：确定ID1在 体外和体内对HIF1α抑制的抗性。目的2：阐明ID1的作用机制 缺氧时，蛋白质受HIF1α的调控。目标3：确定ID1产生抗药性的机制 缺氧对HIF1α的抑制作用。这些目标的顺利实现可能会加深我们对 HIF1α在肿瘤生物学和治疗中的作用，可能为临床翻译提供一种合理的途径 HIF1α抑制药，并可能为晚期和慢性粒细胞白血病患者带来新的挽救生命的治疗方法 转移性疾病。

Project Summary Patients with advanced and metastatic cancer have limited treatment options and face grim outcomes. There is an urgent need for novel and effective treatments. Hypoxia is a universal pathological feature of solid tumors. Hypoxic tumor cells acquire metastatic and lethal phenotypes primarily through the activities of hypoxia- inducible factor 1 alpha (HIF1α). Therefore, HIF1α is considered as a promising therapeutic target. To date, while several HIF1α inhibitors have been discovered and validated in preclinical studies, the clinical translations of these agents have been less successful. The robust antitumor effects seen in preclinical models are not observed in clinical trials. The reasons for the poor clinical efficacy are unclear. Thus, the long-term goal of this proposal is to understand how tumor cells adaptively respond and develop resistance to HIF1α inhibition, and harness this knowledge to translate HIF1α inhibitors into clinically effective and sustainable treatments. In preliminary studies, we specifically inhibited HIF1α using stable shRNA in multiple human tumor cell lines. We found that although tumor cells were initially sensitive to the antitumor activities of HIF1α inhibition, they quickly developed resistance in hypoxia in vitro and in xenografts in vivo even though HIF1α remained inhibited. Mechanistically, we observed that tumor cells adaptively responded to HIF1α inhibition by increasing the stability of oncogenic protein ID1 in hypoxia, and we found that silencing ID1 restored sensitivity to HIF1α inhibition, while overexpressing ID1 conferred resistance. In this proposal, we will test the hypothesis that HIF1α inhibition induces adaptive resistance via compensatory stabilization of oncogenic protein ID1 in hypoxia, which in turn supports the hypoxic growth of HIF1α-inhibited tumors. We further hypothesize that silencing ID1 or ID1-mediated oncogenic pathways will block the resistance and enhances the antitumor efficacy of HIF1α inhibition. We will use molecular biology and preclinical animal models to test this hypothesis in three specific aims. Aim 1: Determine the role of ID1 in conferring resistance to HIF1α inhibition in vitro and in vivo. Aim 2: Elucidate the mechanism by which ID1 protein is regulated by HIF1α in hypoxia. Aim 3: Determine the mechanism by which ID1 confers resistance to HIF1α inhibition in hypoxia. The successful completion of these aims may deepen our understanding of the role of HIF1α in cancer biology and therapy, may provide a rational approach to the clinical translation of HIF1α-inhibitory agents, and may lead to novel and lifesaving treatments for patients with advanced and metastatic disease.