Absence of K-Ras Reduces Proliferation and Migration But Increases Extracellular Matrix Synthesis in Fibroblasts. Absence of K-Ras Reduces Proliferation and Migration But Increases Extracellular Matrix Synthesis in Fibroblasts. Muñoz-Félix JM, Fuentes-Calvo I, Cuesta C, Eleno N, Crespo P, López-Novoa JM, Martínez-Salgado C. J Cell Physiol. 2016 Feb 12. [Epub ahead of print]2016-02-11T23:00:00Z<p style="text-align:justify;"><span class="ms-rteThemeFontFace-1 ms-rteFontSize-2"><span class="ms-rteThemeForeColor-2-5" style="font-weight:bold;">Abstract</span><br></span></p><div style="color:#000000;font-family:arial, helvetica, clean, sans-serif;text-align:justify;"><p style="margin-bottom:0.5em;font-size:1.04em;"><span class="ms-rteThemeFontFace-1 ms-rteFontSize-2">The involvement of Ras-GTPases in the development of renal fibrosis has been addressed in the last decade. We have previously shown that H- and N-Ras isoforms participate in the regulation of fibrosis. Herein, we assessed the role of K-Ras in cellular processes involved in the development of fibrosis: proliferation, migration, and extracellular matrix (ECM) proteins synthesis. K-Ras knockout (KO) mouse embryonic fibroblasts (K-ras(-/-) ) stimulated with transforming growth factor-β1 (TGF-β1) exhibited reduced proliferation and impaired mobility than wild-type fibroblasts. Moreover, an increase on ECM production was observed in K-Ras KO fibroblasts in basal conditions. The absence of K-Ras was accompanied by reduced Ras activation and ERK phosphorylation, and increased AKT phosphorylation, but no differences were observed in TGF-β1-induced Smad signaling. The MEK inhibitor U0126 decreased cell proliferation independently of the presence of K-ras but reduced migration and ECM proteins expression only in wild-type fibroblasts, while the PI3K-AKT inhibitor LY294002 decreased cell proliferation, migration, and ECM synthesis in both types of fibroblasts. Thus, our data unveil that K-Ras and its downstream effector pathways distinctively regulate key biological processes in the development of fibrosis. Moreover, we show that K-Ras may be a crucial mediator in TGF-β1-mediated effects in this cell type. J. Cell. Physiol. 231: 2224-2235, 2016.</span><br></p></div><p>​<span style="color:#474f51;font-family:"yanone kaffeesatz";font-size:18px;background-color:#ffffff;">[</span><a href="http://www.ncbi.nlm.nih.gov/pubmed/26873620" style="color:#ed391b;margin:0px;padding:0px;border:0px;font-stretch:inherit;font-size:18px;line-height:inherit;font-family:"yanone kaffeesatz";vertical-align:baseline;background-color:#ffffff;">PubMed</a><span style="color:#474f51;font-family:"yanone kaffeesatz";font-size:18px;background-color:#ffffff;">]</span><br></p>47