Signaling pathway cooperation in TGF-β-induced epithelial-mesenchymal transition

Regulation of epithelial-mesenchymal transition in breast cancer cells by cell contact and adhesion

Epithelial-mesenchymal transition (EMT) is a physiological program that is activated during cancer cell invasion and metastasis. We show here that EMT-related processes are linked to a broad and conserved program of transcriptional alterations that are influenced by cell contact and adhesion. Using cultured human breast cancer and mouse mammary epithelial cells, we find that reduced cell density, conditions under which cell contact is reduced, leads to reduced expression of genes associated with mammary epithelial cell differentiation and increased expression of genes associated with breast cancer. We further find that treatment of cells with matrix metalloproteinase-3 (MMP-3), an inducer of EMT, interrupts a defined subset of cell contact-regulated genes, including genes encoding a variety of RNA splicing proteins known to regulate the expression of Rac1b, an activated splice isoform of Rac1 known to be a key mediator of MMP-3-induced EMT in breast, lung, and pancreas. These results provide new insights into how MMPs act in cancer progression and how loss of cell-cell interactions is a key step in the earliest stages of cancer development.

Increased expression of bone morphogenetic protein-7 and its related pathway provides an anti-fibrotic effect on silica induced fibrosis in vitro

BMP-7 exerts an inhibitory effect on silica induced fibrosis in RLE-6TN cells via suppressing TGF-β signaling and activating BMP signaling.

Protein interactions of cortactin in relation to invadopodia formation in metastatic renal clear cell carcinoma

In the present study, we wanted to examine the predominant factor/s in the initiation of metastasis. We used samples of advanced grades of renal clear cell carcinoma with documented clinical history of vena caval spread as the experimental group. The major rationale for this selection is the fact that renal cell carcinoma metastasize extensively through the inferior vena cava up to the pulmonary bed and often exist as a continuous mass of metastatic tissue. As cortactin plays a significant role in invadopodia formation during initiation of metastasis, in the present study, we tested expression of cortactin and phospho(tyr421)-cortactin in different grades of renal cell clear carcinoma and examined its property to bind to actin. The findings of the present study suggest that the variations of the local physiological milieu are the driving forces for metastasis by enhancing molecular mechanisms for lamellipodia formation. We conclude that localization of cortactin in cancer cells and interaction between actin and its nucleators are crucial for cancer progression.

Glomerular endothelial cell injury and cross talk in diabetic kidney disease

Diabetic kidney disease (DKD) remains a leading cause of new-onset end-stage renal disease (ESRD), and yet, at present, the treatment is still very limited. A better understanding of the pathogenesis of DKD is therefore necessary to develop more effective therapies. Increasing evidence suggests that glomerular endothelial cell (GEC) injury plays a major role in the development and progression of DKD. Alteration of the glomerular endothelial cell surface layer, including its major component, glycocalyx, is a leading cause of microalbuminuria observed in early DKD. Many studies suggest a presence of cross talk between glomerular cells, such as between GEC and mesangial cells or GEC and podocytes. PDGFB/PDGFRβ is a major mediator for GEC and mesangial cell cross talk, while vascular endothelial growth factor (VEGF), angiopoietins, and endothelin-1 are the major mediators for GEC and podocyte communication. In DKD, GEC injury may lead to podocyte damage, while podocyte loss further exacerbates GEC injury, forming a vicious cycle. Therefore, GEC injury may predispose to albuminuria in diabetes either directly or indirectly by communication with neighboring podocytes and mesangial cells via secreted mediators. Identification of novel mediators of glomerular cell cross talk, such as microRNAs, will lead to a better understanding of the pathogenesis of DKD. Targeting these mediators may be a novel approach to develop more effective therapy for DKD.