The retinoblastoma cell cycle regulator pRb and the two related proteins p107 and p130 are thought to suppress cancer development both by inhibiting the G1/S transition of the cell cycle in response to growth-arrest signals and by promoting cellular differentiation. Here, we investigated the phenotype of Rb family triple knock-out (TKO) embryonic stem cells as they differentiate in vivo and in culture. Confirming the central role of the Rb gene family in cell cycle progression, TKO mouse embryos did not survive past mid-gestation and differentiating TKO cells displayed increased proliferation and cell death. However, patterning and cell fate determination were largely unaffected in these TKO embryos. Furthermore, a number of TKO cells, including in the neural lineage, were able to exit the cell cycle in G1 and terminally differentiate. This ability of Rb family TKO cells to undergo cell cycle arrest was associated with the repression of target genes for the E2F6 transcription factor, uncovering a pRb-independent control of the G1/S transition of the cell cycle. These results show that the Rb gene family is required for proper embryonic development but is not absolutely essential to induce G1 arrest and differentiation in certain lineages.
G1 arrest and differentiation can occur independently of Rb family function.
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View SamplesHypertrophic scar (HTS) formation is characterized by exuberant fibroproliferation for reasons that remain poorly understood1. One important but often overlooked component of wound repair is mechanical force, which regulates reciprocal cell-matrix interactions through focal adhesion components including focal adhesion kinase (FAK)1,2. Here we report that FAK is activated following cutaneous injury and that this activation is potentiated by mechanical loading. Transgenic mice lacking fibroblast-specific FAK exhibit significantly less fibrosis in a preclinical model of HTS formation. Inflammatory pathways involving monocyte chemoattractant protein-1 (MCP-1), a chemokine highly implicated in human skin fibrosis3, are triggered following FAK activation, mechanistically linking physical force to fibrosis. Further, small molecule inhibition of FAK effectively abrogates fibroproliferative mechanisms in human cells and significantly reduces scar formation in vivo. Collectively, these findings establish a molecular basis for HTS formation based on the mechanical activation of fibroblast-specific FAK and demonstrate the therapeutic potential of targeted mechanomodulatory strategies.
Focal adhesion kinase links mechanical force to skin fibrosis via inflammatory signaling.
Sex, 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
View SamplesIn this dataset, we include the expression data obtained from KRas expressing tumors, matched Kras expressing tumor spheres, surviving cells and surviving cells after KRas re-expression for 24hs
Oncogene ablation-resistant pancreatic cancer cells depend on mitochondrial function.
Specimen part
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