Aldo-keto reductase family 1 member B10 AKR1B10 in pancreatic carcinogenesis

描述（由申请人提供）：该项目的目的是确定醛酮还原酶家族1成员B10（AKR 1B 10）在胰腺癌发生中的作用，并建立一种使用强效AKR 1B 10抑制剂预防胰腺癌的有效策略。AKR 1B 10属于醛酮还原酶（AKR）家族，是一种独特的肿瘤生物标志物，在包括胰腺在内的吸烟相关癌中过表达。AKR 1B 10的底物特异性比大多数人AKR的底物特异性更受限制：只有法尼醛、香叶基香叶醛、视黄醛和羰基是其特异性底物。AKR 1B 10可以通过多种方式促进肿瘤的发生，包括调节细胞脂肪酸合成和类异戊二烯代谢，代谢高活性羰基，以及调节肿瘤中视网膜的稳态。我们的初步数据进一步表明AKR 1B 10在胰腺癌发生中的重要性。1)我们已经证明i）23/36（64%）胰腺腺癌过表达AKR 1B 10，并且70%的AKR 1B 10过表达的患者是吸烟者。AKR 1B 10在早期癌前病变PanIN和突变Kras等位基因的小鼠胰腺癌中过表达。2)在胰腺癌细胞中通过siRNA沉默AKR 1B 10导致诱导凋亡和抑制蛋白质异戊二烯化，包括Kras和HDJ 2。3)双氯芬酸和舒林酸[非甾体抗炎药（NSAID）]是AKR 1B 10的竞争性抑制剂。我们的研究表明，双氯芬酸和舒林酸抑制胰腺癌细胞中AKR 1B 10活性并降低Kras蛋白异戊二烯化，并在两种胰腺癌基因工程小鼠模型中显著抑制胰腺癌发生并增加动物存活率。4)本实验室已成功建立了转基因AKR 1B 10 fl/fl小鼠和几种胰腺癌小鼠模型。我们的假设是AKR 1B 10的敲除或抑制将抑制胰腺癌的发展，其机制是通过i）通过代谢类异戊二烯抑制致癌Kras蛋白和其他关键异戊二烯化蛋白的活化，ii）影响羰基代谢和/或iii）调节肿瘤中的视网膜稳态。我们将执行以下特定目的来检验这一假设：目的1：确定双氯芬酸对Pdx 1Cre-KrasG 12 D小鼠（称为PanKras）中突变型Kras驱动和胰腺炎增强的致癌作用和机制。目标二：使用同时敲除AKR 1B 10和激活胰腺Pdx 1+祖细胞中KrasG 12 D等位基因的最强大的三转基因Pdx 1Cre-KrasG 12 D-AKR 1B 10 fl/fl小鼠（称为PanKras/AKR 1B 10）小鼠模型，确定AKR 1B 10基因缺陷在胰腺癌发生中的作用。目标3：确定视黄醇（维生素A）和双氯芬酸对抑制PanKras小鼠胰腺癌发生的协同作用，并确定维生素A和双氯芬酸的协同作用是否通过调节肿瘤中的视网膜稳态。

DESCRIPTION (provided by applicant): The objective of this project is to determine the role of aldo-keto reductase family 1 member B10 (AKR1B10) in pancreatic carcinogenesis and to establish an efficient strategy for the prevention of pancreatic cancer using a potent AKR1B10 inhibitor. AKR1B10 belongs to the aldo-keto reductase (AKR) family and is a unique tumor biomarker that is over-expressed in smoking-related carcinomas including pancreas. AKR1B10 exhibits more restricted substrate specificity than that of most human AKR: only farnesal, geranylgeranial, retinal and carbonyls are its specific substrates. AKR1B10 could promote carcinogenesis in several ways, including regulating cellular fatty acid synthesis and isoprenoid metabolism, metabolizing highly active carbonyls, and regulating retinal homeostasis in the tumor. Our preliminary data further indicate the importance of AKR1B10 in pancreatic carcinogenesis. 1) We have demonstrated that i) 23/36 (64%) pancreatic adenocarcinomas over-expressed AKR1B10 and 70% patients with AKR1B10 over-expression were smokers. AKR1B10 was over-expressed in early precancerous PanIN lesions and in mouse pancreatic carcinomas with mutant Kras allele. 2) Silencing AKR1B10 by siRNA in pancreatic carcinoma cells resulted in induction of apoptosis and inhibition of protein prenylation including Kras and HDJ2. 3) Diclofenac and Sulindac [non- steroidal anti-inflammatory drugs (NSAIDs)] are competitive inhibitors of AKR1B10. Our studies showed that diclofenac and sulindac inhibited AKR1B10 activity and reduced Kras protein prenylation in pancreatic carcinoma cells, and significantly inhibited pancreatic carcinogenesis and increased animal survival in the two genetically engineered mouse models of pancreatic cancers. 4) Transgenic flox-p AKR1B10fl/fl mice (AKR1B10fl/fl) and several powerful murine models of pancreatic carcinoma have been fully developed and well used in our lab. Our hypothesis is that knockout or inhibition of AKR1B10 will inhibit the development of pancreatic carcinoma, mechanistically through i) inhibiting activation of oncogenic Kras protein and other key prenylated proteins via metabolizing isoprenoids, ii) affecting carbonyl metabolism and/or iii) regulating retinal homeostasis in tumors. We will perform the following specific Aims to test this hypothesis: Aim 1: To determine the chemopreventive effects and mechanism of diclofenac on mutant Kras-driven and pancreatitis-enhanced carcinogenesis in Pdx1Cre-KrasG12D mice (called PanKras). Aim 2: To determine the role of AKR1B10 gene deficiency in pancreatic carcinogenesis using a most powerful mouse model of the tri-transgenic Pdx1Cre-KrasG12D-AKR1B10fl/fl mice (called PanKras/AKR1B10) that concurrently knockout AKR1B10 and activating KrasG12D allele in the pancreatic Pdx1+ progenitor cells. Aim 3: To determine the synergistic effect of retinol (vitamin A) and diclofenac on inhibiting pancreatic carcinogenesis in PanKras mice and to determine if the synergistic effect of vitamin A and diclofenac is via modulating retinal homeostasis in the tumor.