Publications by authors named "Guillem Lambies"

Article Synopsis
  • Macropinocytosis is a survival strategy used by cancer cells, especially in nutrient-poor environments, relying heavily on glutamine to sustain themselves, particularly in pancreatic ductal adenocarcinoma (PDAC) cells.
  • The atypical protein kinase C (aPKC) enzymes, specifically PKCζ and PKCι, play a crucial role in regulating macropinocytosis by interacting with scaffold proteins that influence cell structure and function.
  • The research shows that aPKCs enhance macropinocytosis through the relocation of Par3 to microtubules, and their depletion adversely affects cell viability, which can be reversed by restoring macropinocytosis, highlighting the significance of aPKCs in supporting
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Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest solid cancers and thus identifying more effective therapies is a major unmet need. In this study we characterized the super enhancer (SE) landscape of human PDAC to identify novel, potentially targetable, drivers of the disease. Our analysis revealed that is a super enhancer-associated gene in human PDAC.

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Article Synopsis
  • Macropinocytosis is a survival mechanism for cancer cells, especially in nutrient-poor environments like tumors, allowing them to scavenge nutrients such as glutamine.
  • In pancreatic ductal adenocarcinoma (PDAC), the atypical protein kinase C (aPKC) enzymes, specifically PKCζ and PKCι, play a crucial role in regulating this nutrient uptake process.
  • The study reveals that these aPKCs interact with cell polarity proteins and are influenced by EGFR signaling and the CREM transcription factor to facilitate macropinocytosis, which is essential for the growth and survival of PDAC cells in vivo.
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In pancreatic ductal adenocarcinoma (PDAC), glutamine is a critical nutrient that drives a wide array of metabolic and biosynthetic processes that support tumor growth. Here, we elucidate how 6-diazo-5-oxo-L-norleucine (DON), a glutamine antagonist that broadly inhibits glutamine metabolism, blocks PDAC tumor growth and metastasis. We find that DON significantly reduces asparagine production by inhibiting asparagine synthetase (ASNS), and that the effects of DON are rescued by asparagine.

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Macropinocytosis is an evolutionarily conserved endocytic pathway that mediates the nonselective acquisition of extracellular material via large endocytic vesicles known as macropinosomes. In addition to other functions, this uptake pathway supports cancer cell metabolism through the uptake of nutrients. Cells harboring oncogene or tumor suppressor mutations are known to display heightened macropinocytosis, which confers to the cancer cells the ability to survive and proliferate despite the nutrient-scarce conditions of the tumor microenvironment.

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Cell migration is a multifactorial/multistep process that requires the concerted action of growth and transcriptional factors, motor proteins, extracellular matrix remodeling and proteases. In this review, we focus on the role of transcription factors modulating Epithelial-to-Mesenchymal Transition (EMT-TFs), a fundamental process supporting both physiological and pathological cell migration. These EMT-TFs (Snail1/2, Twist1/2 and Zeb1/2) are labile proteins which should be stabilized to initiate EMT and provide full migratory and invasive properties.

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In cancer cells, epithelial-to-mesenchymal transition (EMT) is controlled by Snail1, a transcriptional factor also required for the activation of cancer-associated fibroblasts (CAF). Snail1 is short-lived in normal epithelial cells as a consequence of its coordinated and continuous ubiquitination by several F-box-specific E3 ligases, but its degradation is prevented in cancer cells and in activated fibroblasts. Here, we performed an siRNA screen and identified USP27X as a deubiquitinase that increases Snail1 stability.

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Notch activation in aortic endothelial cells (ECs) takes place at embryonic stages during cardiac valve formation and induces endothelial-to-mesenchymal transition (EndMT). Using aortic ECs, we show here that active Notch expression promotes EndMT, resulting in downregulation of vascular endothelial cadherin (VE-cadherin) and upregulation of mesenchymal genes such as those for fibronectin and Snail1/2. In these cells, transforming growth factor β1 exacerbates Notch effects by increasing Snail1 and fibronectin activation.

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