Metabolic pathways regulate metaplasia and cancer initiation in the pancreas

项目概要 激活 KRAS 中的突变可重新编程细胞代谢，以支持生长、增殖和 胰腺癌的生存率。然而，关于 KRAS 如何依赖的信息很少 新陈代谢的改变有助于癌前状态和癌症的发生。腺泡至 导管化生 (ADM) 是胰腺导管中必需的癌前状态 腺癌。在 ADM 过程中，腺泡细胞转分化，变得更像导管状并且 增殖，通常是对组织损伤的反应。 ADM 是可逆的，但会激活突变 KRAS 导致持续性 ADM 并进展为肿瘤和癌症。最近的研究还 研究表明，健康的腺泡细胞可以限制和消除致癌的 KRAS 表达细胞。 根据初步数据，我假设健康的腺泡细胞在 ADM 有助于氧化还原稳态并限制附近致癌细胞的生长，从而 限制癌症的发生。初步实验表明，6-磷酸葡萄糖 脱氢酶 (G6pd) 和苹果酸酶 1 (Me1) 转录物显着上调 在 ADM 期间。 G6PD 是戊糖磷酸途径中的限速酶，ME1 将苹果酸转化为丙酮酸，连接糖酵解和柠檬酸循环。此外，G6PD 和 ME1 酶产生 NADPH，可防止氧化还原应激。目标 1 将重点关注 G6pd 和 Me1 并确定氧化还原平衡和 NADPH 产生如何促进 ADM 形成。初步实验表明，这些酶的损失增加了 腺泡细胞中的活性氧。目标 1 中提出的实验使用基因 胰腺癌工程小鼠模型、稳态代谢组学、同位素示踪、 和离体原代腺泡细胞培养以检查对 ADM 和肿瘤发生的影响 当 G6pd 和 Me1 丢失时，NADPH 池减少。目标 2 将决定如何 健康细胞和致癌细胞之间的代谢氧化还原相互作用限制了 ADM。初步 实验表明，健康的腺泡细胞分泌代谢物来抑制邻近的 KRAS- 进行 ADM 的表达细胞。该目标使用 KRAS 驱动的诱导小鼠模型 胰腺癌、代谢组学和空间转录组学。拟议的实验将 帮助确定健康细胞如何感知邻近致癌细胞的存在以及 重新编程它们的细胞状态和新陈代谢以抑制癌症的发生。共同目标 该提案中提出的内容将为代谢途径如何发挥作用提供新的机制见解 推动胰腺癌的发生，从而为未来的治疗提供信息。

PROJECT SUMMARY Activating mutations in KRAS reprogram cell metabolism to support growth, proliferation, and survival in pancreatic cancer. However, there is little information on how KRAS-dependent alterations in metabolism contribute to premalignant states and cancer initiation. Acinar-to- ductal metaplasia (ADM) is a precancerous state essential in pancreatic ductal adenocarcinoma. During ADM, acinar cells transdifferentiate to become more duct-like and proliferative, usually in response to tissue damage. ADM is reversible but activating mutations in KRAS lead to persistent ADM and progression to neoplasia and cancer. Recent studies also show that healthy acinar cells can restrict and eliminate oncogenic KRAS-expressing cells. Based on preliminary data, I hypothesize that healthy acinar cells alter their metabolism during ADM to aid in redox homeostasis and restrict the growth of nearby oncogenic cells, thereby restricting cancer initiation. Preliminary experiments show that Glucose-6-phosphate dehydrogenase (G6pd) and Malic enzyme 1 (Me1) transcripts are significantly upregulated during ADM. G6PD is the rate limiting enzyme in the pentose phosphate pathway and ME1 converts malate to pyruvate, linking glycolytic and citric acid cycles. In addition, both G6PD and ME1 enzymes produce NADPH, which protects against redox stress. Aim 1 will focus on G6pd and Me1 and determine how redox balance and NADPH production contribute to ADM formation. Preliminary experiments show that loss of these enzymes increased the level of reactive oxygen species in acinar cells. The experiments proposed in Aim 1 use genetically engineered mouse models of pancreatic cancer, steady-state metabolomics, isotope tracing, and ex vivo primary acinar cell culture to examine the consequence on ADM and tumorigenesis when G6pd and Me1 are lost, and NADPH pools are reduced. Aim 2 will determine how metabolic redox interactions between healthy and oncogenic cells restrict ADM. Preliminary experiments suggest that healthy acinar cells secrete metabolites to inhibit adjacent KRAS- expressing cells from undergoing ADM. This aim uses inducible mouse models of KRAS-driven pancreatic cancer, metabolomics, and spatial transcriptomics. The proposed experiments will help to identify how healthy cells sense the presence of neighboring oncogenic cells and reprogram their cell state and metabolism to repress cancer initiation. Together, the aims presented in this proposal will provide new mechanistic insights on how metabolic pathways drive pancreatic cancer initiation, thereby informing future therapeutics.