Almost all human pancreatic ductal adenocarcinomas (PDACs) are driven by oncogenic Kras and the progression of the disease is characterized by the serial appearance of certain genetic lesions. Mouse models have convincingly shown that Kras mutation induces classical PanIN lesions that can progress to PDAC in the appropriate tumor suppressor background. However, the cooperative mechanism between mutant Kras-dependent signaling surrogates and other oncogenic pathways remains to be fully elucidated in order to devise better therapeutic strategy. Mounting evidence PTEN/PI3K perturbation on PDAC tumorigenesis, we observed frequent PTEN inactivation at both genomic and histopathological levels in primary human PDAC samples. The importance of PTEN/PI3K pathway during the development of PDAC was further supported by genetic studies demonstrating that Pten deficiency in cooperation with Kras activation accelerated the formation of invasive PDAC. Mechanistically, combined Kras mutation and Pten inactivation leads to NFkB activation and subsequent induction of cytokine pathways, accompanied with strong stromal activation and immune cell infiltration. Therefore, PTEN/PI3K pathway dictates the activity of NFkB network and serves as a major surrogate during Kras-mediated pancreatic tumorigenesis.
PTEN is a major tumor suppressor in pancreatic ductal adenocarcinoma and regulates an NF-κB-cytokine network.
Specimen part
View SamplesThe maintenance of advanced malignancies relies on continued activity of driver oncogenes, although their rate-limiting role is highly context-dependent with respect to tumor types and associated genetic alterations. Oncogenic Kras mutation is the signature event in human pancreatic ductal adenocarcinoma (PDAC), serving a critical role in tumor initiation. Here, an inducible KrasG12D-driven p53 mutant PDAC mouse model establishes that advanced PDAC remains strictly dependent on continued KrasG12D expression and that KrasG12D serves a vital role in the control of tumor metabolism, through stimulation of glucose uptake and channeling of glucose intermediates through the hexosamine biosynthesis pathway (HBP) and the pentose phosphate pathway (PPP). Notably, these studies reveal that oncogenic Kras regulates ribose biogenesis. Unlike canonical models of PPP-mediated ribose biogenesis, we demonstrate that oncogenic Kras drives intermediates from enhanced glycolytic flux into the non-oxidative arm of the PPP, thereby decoupling ribose biogenesis from NADPNADPH-mediated redox control. Together, this work provides in vivo mechanistic insights into how oncogenic Kras promotes metabolic reprogramming in native tumors and illuminates potential metabolic targets that can be exploited for therapeutic benefit in Kras-driven PDAC.
Oncogenic Kras maintains pancreatic tumors through regulation of anabolic glucose metabolism.
Specimen part, Treatment
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