Metabolic pathways regulate metaplasia and cancer initiation in the pancreas

项目摘要 KRAS中的激活突变重新编程细胞代谢以支持生长、增殖和增殖。 胰腺癌的生存率。然而，关于KRAS依赖性如何 代谢的改变导致癌前状态和癌症的发生。腺泡-对- 胰腺导管上皮化生（ADM）是胰腺导管癌的一种癌前状态， 腺癌在ADM过程中，腺泡细胞转分化，变得更像导管， 增殖，通常是对组织损伤的反应。ADM是可逆的，但激活突变， KRAS导致持续性ADM并进展为瘤形成和癌症。最近的研究还 表明健康的腺泡细胞可以限制和消除表达致癌KRAS的细胞。 基于初步的数据，我假设健康的腺泡细胞改变他们的代谢过程中， 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，葡萄糖-6-磷酸 脱氢酶（G6 pd）和苹果酸酶1（Me 1）转录物显著上调 在ADM期间，G6 PD是戊糖磷酸途径中的限速酶，ME 1 将苹果酸转化为丙酮酸，连接糖酵解和柠檬酸循环。此外，G6 PD和 ME 1酶产生NADPH，其保护免受氧化还原应激。目标1将专注于G6 pd 和Me 1，并确定氧化还原平衡和NADPH的产生如何有助于ADM 阵初步实验表明，这些酶的损失增加了 腺泡细胞中的活性氧。目标1中提出的实验使用遗传学方法， 胰腺癌的工程小鼠模型，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ADM和肿瘤发生的结果 当G6 pd和Me 1丢失时，NADPH库减少。目标2将决定如何 健康和致癌细胞之间的代谢氧化还原相互作用限制ADM。 实验表明，健康的腺泡细胞分泌代谢物来抑制邻近的KRAS- 该目的使用KRAS驱动的诱导型小鼠模型， 胰腺癌、代谢组学和空间转录组学。拟议的实验将 有助于识别健康细胞如何感知邻近致癌细胞的存在， 重新编程他们的细胞状态和代谢来抑制癌症的发生。共同的目标 在这项提案中提出的将提供新的机制的见解如何代谢途径 驱动胰腺癌的发生，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.