RAC1 P29 is the third most commonly mutated codon in human cutaneous melanoma, after BRAF V600 and NRAS Q61. Here, we study the role of RAC1 in melanoma development and reveal that RAC1 activates PAK, AKT, and a gene expression program initiated by the SRF/MRTF transcriptional pathway, which results in a melanocytic to mesenchymal phenotypic switch. Mice with ubiquitous expression of RAC1 from the endogenous locus develop lymphoma. When expressed only in melanocytes, RAC1 cooperates with oncogenic BRAF or with NF1-loss to promote tumorigenesis. RAC1 also drives resistance to BRAF inhibitors, which is reversed by SRF/MRTF inhibitors. These findings establish RAC1 as a promoter of melanoma initiation and mediator of therapy resistance, while identifying SRF/MRTF as a potential therapeutic target.
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http://dx.doi.org/10.1016/j.ccell.2019.05.015 | DOI Listing |
Adv Sci (Weinh)
January 2025
Department of Critical Care Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, 510280, China.
Older individuals experience increased susceptibility and mortality to bacterial infections, but the underlying etiology remains unclear. Herein, it is shown that aging-associated reduction of commensal Parabacteroides goldsteinii (P. goldsteinii) in both aged mice and humans critically contributes to worse outcomes of bacterial infection.
View Article and Find Full Text PDFCells
January 2025
Department of Agricultural and Environmental Sciences, University of Milan, 20133 Milan, Italy.
Microplastics (MPs) in fish can cross the intestinal barrier and are often bioaccumulated in several tissues, causing adverse effects. While the impacts of MPs on fish are well documented, the mechanisms of their cellular internalization remain unclear. A rainbow-trout () intestinal platform, comprising proximal and distal intestinal epithelial cells cultured on an Alvetex scaffold, was exposed to 50 mg/L of MPs (size 1-5 µm) for 2, 4, and 6 h.
View Article and Find Full Text PDFSmall
January 2025
Department of Orthopedics, Laboratory of Biological Tissue Engineering and Digital Medicine, Affiliated Hospital of North Sichuan Medical College, No. 1 The South of Maoyuan Road, Nanchong, Sichuan, 637000, P. R. China.
Efferocytosis in macrophages typically engages an anti-inflammatory positive feedback regulatory mechanism. In osteoarthritis (OA), characterized by imbalanced inflammatory homeostasis, the proinflammatory state of macrophages in the immune microenvironment can be reversed through enhanced efferocytosis. This study develops an in situ proefferocytosis hydrogel microsphere (macrophage polarity converter, H-C@IL) for OA treatment.
View Article and Find Full Text PDFInt J Biochem Cell Biol
January 2025
Laboratory of Signaling in Biomolecular Systems, Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil. Electronic address:
Int J Mol Sci
December 2024
Department of Molecular Pathobiology, New York University College of Dentistry, 345 E 24th Street, New York, NY 10010, USA.
The notochord is an axial structure required for the development of all chordate embryos, from sea squirts to humans. Over the course of more than half a billion years of chordate evolution, in addition to its structural function, the notochord has acquired increasingly relevant patterning roles for its surrounding tissues. This process has involved the co-option of signaling pathways and the acquisition of novel molecular mechanisms responsible for the precise timing and modalities of their deployment.
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