Ral GTPases as novel regulators of acinar cell plasticity in the pancreas – implications for cancer development and treatment

Ral GTPases 作为胰腺腺泡细胞可塑性的新型调节剂 â 对癌症发展和治疗的影响

• 批准号: 502983674
• 负责人: Dr. Andrea Oeckinghaus
• 金额: --
• 依托单位: Institut für Molekulare Tumorbiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/502983674?language=en
• 关键词: Ral; GTPases; novel; regulators; acinar

Pancreatic cancer represents one of the deadliest cancers with a 5-year survival rate of 10 %. The initial step in pancreatic ductal adenocarcinoma (PDAC) development is the transdifferentiation of acinar to ductal cells (acinar-to-ductal metaplasia, ADM), which then further progress to form neoplasias and finally invasive carcinoma. We found that loss of RALGAP complexes, negative regulators of signaling by the small RAL GTPases RALA and RALB, sensitizes acinar cells to ADM and drastically increases their susceptibility to oncogenic transformation through oncogenic KRASG12D and PDAC development. RALGAP deficiency also prevents regeneration of the acinar cell compartment after acute pancreatitis, where ADM is normally transient, suggesting deregulation of RALGAP/RAL activity as a risk factor for cancer development. RAL GTPase activity is frequently upregulated in PDAC samples and cell lines. However, no in vivo studies have addressed the role of RAL GTPases in PDAC and RAL GTPase function has until now not been connected to acinar plasticity. The aim of this proposal is to provide a comprehensive analysis of RAL GTPase function(s) in the ADM process. We wish to fully characterize the phenotype of RALGAPβ loss, where RAL GTPases are hyperactive, in respect to ADM and its impact on the inflammatory response upon acute and chronic pancreatitis and we will elucidate when and how RAL GTPase activity is regulated during inflammatory processes in the pancreas. Furthermore, we will investigate the effects of genetic ablation of RALA and/or RALB on ADM and tumor development during acute and chronic inflammation in respective in vivo models. Here, we will be able to characterize, for which phase during acinar plasticity RAL GTPases are critical and whether RAL isoform-specific dependencies exist. As pancreatic cancer remains difficult to treat, there is great research interest in identifying new treatment options. We will test if RAL inhibition using the small molecule BQU57 can prevent or revert ADM and thus serve as an early intervention strategy. Finally, we wish to unravel the signaling pathways and cellular processes that are driven by RAL to control acinar plasticity. We have established 3D organoid and cell culture systems that allow analysis of ADM in ex vivo settings, which we will combine with RNA sequencing and phosphoproteomics approaches to identify critical mediators and processes downstream of RAL GTPases. Our findings will improve our understanding of the regeneration processes after pancreatitis and the initiating events in PDAC development, which we hope will promote the discovery of markers for early detection as well as strategies for early intervention.

胰腺癌是最致命的癌症之一，5年生存率为10%。胰腺导管腺癌（PDAC）发展的第一步是腺泡细胞向导管细胞的转分化（腺泡-导管化生，ADM），然后进一步发展形成瘤形成并最终形成浸润性癌。我们发现，RALGAP复合物（小RAL GTP酶RALA和RALB的信号传导负调控因子）的丢失使腺泡细胞对ADM敏感，并通过致癌KRASG 12 D和PDAC的发展显著增加了它们对致癌转化的易感性。RALGAP缺陷还阻止了急性胰腺炎后腺泡细胞隔室的再生，其中ADM通常是短暂的，这表明RALGAP/RAL活性失调是癌症发展的危险因素。RAL GT3活性在PDAC样品和细胞系中经常上调。然而，没有体内研究已经解决了RAL GTP酶在PDAC中的作用，并且RAL GTP酶功能迄今为止尚未与腺泡可塑性相关。本提案的目的是对行政管理过程中的RAL GTIFE功能进行全面分析。我们希望充分表征RALGAPβ损失的表型，其中RAL GTP酶相对于ADM及其对急性和慢性胰腺炎炎症反应的影响是过度活跃的，我们将阐明在胰腺炎症过程中RAL GTP酶活性何时以及如何受到调节。此外，我们将研究基因消融RALA和/或RALB对ADM和肿瘤发展的影响，在急性和慢性炎症在各自的体内模型。在这里，我们将能够表征，在腺泡可塑性RAL GTP酶是至关重要的，以及RAL异构体特异性依赖性是否存在。由于胰腺癌仍然难以治疗，因此对确定新的治疗方案有很大的研究兴趣。我们将测试使用小分子BQU 57的RAL抑制是否可以预防或逆转ADM，从而作为早期干预策略。最后，我们希望解开的信号通路和细胞过程，由RAL控制腺泡可塑性。我们已经建立了3D类器官和细胞培养系统，允许在离体环境中分析ADM，我们将联合收割机与RNA测序和磷酸化蛋白质组学方法相结合，以鉴定RAL GTP酶下游的关键介质和过程。 我们的研究结果将提高我们对胰腺炎后再生过程和PDAC发展中起始事件的理解，我们希望这将促进早期检测标记物的发现以及早期干预策略的发现。