Targeting Stromal Influences on BCKA Addiction in PDAC Tumors

胰腺导管腺癌（PDAC）的传统治疗失败是由于我们的局限性， 了解肿瘤微环境（TME）如何促进快速进展或复发 关于PDAC在PDAC中，被鉴定为癌症相关成纤维细胞（CAF）的基质细胞占PDAC的高达10%。 肿瘤体积的90%。最近的研究揭示了支链氨基酸的重要性 （BCAAs）在癌症。然而，基质细胞在支持肿瘤中BCAA代谢中的作用仍然很差 明白了解癌症-基质生态系统需要深入了解癌症-基质的交叉点。 与BCAA代谢重编程相关的基质转化。SMAD 4缺失是一种 PDAC中的常见事件。然而，SMAD 4缺失的PDAC细胞在调节细胞活化中的代谢作用， 基质细胞转化是未知的。我们在此提出的目标旨在弥合这一知识差距。 我们提出在PDAC肿瘤的癌和间质区室中存在不同的BCAA代谢， 揭示了PDAC细胞对基质中CAF分泌的支链酮酸（BCKAs）的严重依赖， 丰富的肿瘤。我们假设反应性间质BCAA代谢从静止间质改变， 通过分泌BCKAs调节PDAC细胞生长的驱动因素。第二，SMAD 4缺失的PDAC细胞诱导 基质细胞的代谢改变。首先，我们将验证基质BCKA合成代谢途径作为一种代谢途径。 患者来源的循环肿瘤细胞（CTC）-类器官和患者来源的组织切片中的致死靶标，使用 基于13 C的同位素示踪和遗传工具，并揭示了CAF分泌的细胞外基质（ECM）是一种 来源BCKA为了了解ECM降解的机制，我们将调节蛋白酶体， CTC-类器官和患者来源的组织切片中ECM的蛋白水解。第二，为了阐明SMAD 4缺失， 在PDAC细胞诱导的CAF代谢重新连接中，我们提出了功能丧失的研究，并使用CTC- 类器官和组织切片，以证明SMAD 4缺失的PDAC细胞对基质的依赖性增加。 基质BCAT 1和阐明SMAD 4缺失的CTC类器官中随时间推移的时间代谢重编程 类器官形成的过程第三，我们将测试CAF中靶向BCKA拮抗剂的功效， 条件性敲除小鼠，并使用患者-细胞模型进行靶向基质BCKA合成代谢途径的体内研究。 衍生的低传代细胞系和同基因同种异体移植物模型。重要的是，我们将抑制基质BCAT 1， 使用加巴喷丁、Erg 240（来自Ergon Pharma的BCAT 1抑制剂）、ERG 245（BCAT 1/2 来自Ergon Pharma的抑制剂），以及CAF中BCAT 1的CRISPR靶向。值得注意的是，我们提出的目标将揭示一个 新的BCAA代谢为中心的调节作用，反应性基质在癌症中，并将揭示潜在的 本条例的作用方式。这些发现可能会导致针对沟通的新疗法 癌细胞和它们的微环境之间的关系。

Failure of traditional therapy in pancreatic ductal adenocarcinoma (PDAC) is due to our limited understanding of how the tumor microenvironment (TME) can facilitate the rapid progression or recurrence of PDAC. In PDAC, the stromal cells identified as cancer associated fibroblasts (CAFs) account for up to 90% of tumor volume. Recent studies have revealed the significance of branched chain amino acids (BCAAs) in cancer. However, the role of stromal cells in support of BCAA metabolism in tumors is still poorly understood. Understanding cancer-stromal ecosystem requires insight into the intersection of cancer- associated transformations in the stroma with reprogramming of their BCAA metabolism. SMAD4 deletion is a frequent event in PDAC. However, the metabolic role of SMAD4-deleted PDAC cells in modulating activation of stromal cell transformation is unknown. Our proposed aims here have aimed to bridge this knowledge gap. We propose a differential BCAA metabolism in cancer and stromal compartments of PDAC tumors and uncover a heavy reliance of PDAC cells on CAF-secreted branched chain keto acids (BCKAs) in stromal- rich tumors. We hypothesize that reactive stromal BCAA metabolism is altered from quiescent stroma and is the driver for regulating PDAC cell growth by secreting BCKAs. Second, SMAD4-deleted PDAC cells induces metabolic alterations in stromal cells. First, we will validate stromal BCKA synthesis metabolic pathway as a lethal target in patient-derived circulating tumor cell (CTC)-organoids and patient-derived tissue slices, using 13C-based isotope tracing and genetic tools and unravel that CAF-secreted extracellular matrix (ECM) is a source for BCKA. To understand the mechanism behind ECM degradation, we will regulate proteasomal proteolysis of ECM in CTC-organoids and patient-derived tissue slices. Second, to elucidate SMAD4-deletion in PDAC cells induced metabolic rewiring of CAFs we have proposed loss-of-function studies and use CTC- organoids and tissue slices to demonstrate increased stromal-reliance of SMAD4-deleted PDAC cells on stromal BCAT1 and elucidate temporal metabolic reprogramming in SMAD4-deleted CTC-organoids over time course of organoid formation. Third, we will test the efficacy of targeting BCKA anabolism in CAFs with conditional knockout mice and perform in vivo studies targeting stromal BCKA anabolic pathway using patient- derived low-passage cell lines and the syngeneic allograft model. Importantly, we will inhibit stromal BCAT1 in the proposed Aims using Gabapentin, Erg 240 (BCAT1 inhibitor from Ergon Pharma), ERG 245 (BCAT1/2 inhibitor from Ergon Pharma), & CRISPR targeting of BCAT1 in CAFs. Notably, our proposed aims will reveal a novel BCAA metabolism-centric regulatory role of reactive stroma in cancers and will uncover the underlying mode of action of this regulation. These findings can lead to novel therapeutics targeting communication between cancer cells and their microenvironment.