Diet-induced obesity (DIO) promotes pancreatic ductal adenocarcinoma (PDAC) in mice expressing KRasG12D in the pancreas (KC mice), but the precise mechanisms remain unclear. Here, we performed multiplex quantitative proteomic and phosphoproteomic analysis by liquid chromatography–tandem mass spectrometry and further bioinformatic and spatial analysis of pancreas tissues from control-fed versus DIO KC mice after 3, 6, and 9 months. Normal pancreatic parenchyma and associated proteins were steadily eliminated and the novel proteins, phosphoproteins, and signaling pathways associated with PDAC tumorigenesis increased until 6 months, when most males exhibited cancer, but females did not. Differentially expressed proteins and phosphoproteins induced by DIO revealed the crucial functional role of matrisomal proteins, which implies the roles of upstream regulation by TGFβ, extracellular matrix-receptor signaling to downstream PI3K-Akt-mTOR-, MAPK-, and Yap/Taz activation, and crucial effects in the tumor microenvironment such as metabolic alterations and signaling crosstalk between immune cells, cancer-associated fibroblasts (CAFs), and tumor cells. Staining tissues from KC mice localized the expression of several prognostic PDAC biomarkers and elucidated tumorigenic features, such as robust macrophage infiltration, acinar–ductal metaplasia, mucinous PanIN, distinct nonmucinous atypical flat lesions (AFLs) surrounded by smooth muscle actin-positive CAFs, invasive tumors with epithelial–mesenchymal transition arising close to AFLs, and expanding deserted areas by 9 months. We next used Nanostring GeoMX to characterize the early spatial distribution of specific immune cell subtypes in distinct normal, stromal, and PanIN areas. Taken together, these data richly contextualize DIO promotion of Kras-driven PDAC tumorigenesis and provide many novel insights into the signaling pathways and processes involved.
饮食诱导的肥胖（DIO）会促进胰腺表达KRasG12D的小鼠（KC小鼠）发生胰腺导管腺癌（PDAC），但其具体机制尚不明确。本研究通过液相色谱-串联质谱法对对照组与DIO组KC小鼠在3、6、9个月时的胰腺组织进行多重定量蛋白质组学及磷酸化蛋白质组学分析，并进一步开展生物信息学与空间分析。结果显示，正常胰腺实质及相关蛋白持续减少，而与PDAC肿瘤发生相关的新型蛋白、磷酸化蛋白及信号通路持续增加至6个月——此时多数雄性小鼠已出现癌变，而雌性小鼠未发生癌变。DIO诱导的差异表达蛋白及磷酸化蛋白揭示了基质蛋白的关键功能作用，这暗示了TGFβ的上游调控作用、细胞外基质-受体信号向下游PI3K-Akt-mTOR通路、MAPK通路及Yap/Taz通路的激活传导，以及在肿瘤微环境中的关键效应（如代谢改变、免疫细胞-癌症相关成纤维细胞（CAFs）-肿瘤细胞间的信号串扰）。通过对KC小鼠组织的染色定位，本研究明确了多个PDAC预后生物标志物的表达，并揭示了以下致瘤特征：显著的巨噬细胞浸润、腺泡-导管化生、黏液性胰腺上皮内瘤变（PanIN）、被平滑肌肌动蛋白阳性CAFs包围的非黏液性非典型扁平病变（AFLs）、紧邻AFLs发生上皮-间质转化的侵袭性肿瘤，以及至9个月时持续扩大的荒芜区域。进一步采用Nanostring GeoMX技术对特定正常区域、间质区域及PanIN区域中特定免疫细胞亚型的早期空间分布特征进行解析。综上所述，本研究系统阐释了DIO促进Kras驱动型PDAC肿瘤发生的时空动态特征，并为相关信号通路及生物学过程提供了诸多创新见解。
肿瘤(癌症)患者之家