TGF-beta1 has been postulated as a pro-oncogenic factor in the late step of the tumoral progression. In transformed cells, TGF-beta1 enhances the capacity to degrade the extracellular matrix, cell invasiveness and epithelial-mesenchymal transition, which are crucial steps for metastasis. Urokinase-type plasminogen activator (uPA) and matrix metalloproteinase-9 (MMP-9) are critical components in cell migration and invasion induced by TGF-beta1, however, the exact mechanism by which TGF-beta1 regulates uPA and MMP-9 is not well elucidated so far. In the present study, we analyzed the role of ROS-NFkappaB, signal as mediator in the cell malignity enhancement by TGF-beta1. We found that TGF-beta1 activates NFkappaB, through Rac1-NOXs-ROS-dependent mechanism. Our results shows that TGF-beta1 stimulation of uPA and MMP-9 expression involve NOXs-dependent ROS and NFkappaB, activation, demonstrated by using DPI, NOXs inhibitor, ROS scavenger N-acetylcysteine and SN50, an NFkb inhibitor. Furthermore, we found that the inhibition of ROS and NFkappaB, abrogates TGF-beta1 stimulation of EMT, cell motility and invasion. Thus, ROS-NFkappaB acts as the crucial signal in TGF-beta1-induced uPA and MMP-9 expression thereby mediating the enhancement of cellular malignity by TGF-beta1.

Background:The influence of the stromal microenvironment on the progression of epithelial cancers has been demonstrated. Unravelling the mechanisms by which stromal cells affect epithelial behaviour will contribute in understanding cellular malignancy. It has been proposed that redox environment has a role in the acquisition of malignancy. In this work, we studied the influence of epithelial cells on the stromal redox status and the consequence of this phenomenon on MCF-7 cell motility.Methods:We analysed in a co-culture system, the effect of RMF-EG mammary stromal cells on the migratory capacity of MCF-7 cell line. To test whether the NOX-dependent stromal redox environment influences the epithelial migratory behaviour, we knocked down the expression of NOX4 using siRNA strategy. The effect of TGF-β1 on NOX4 expression and activity was analysed by qPCR, and intracellular ROS production was measured by a fluorescent method.Results:Migration of MCF-7 breast epithelial cells was stimulated when co-cultured with RMF-EG cells. This effect depends on stromal NOX4 expression that, in turn, is enhanced by epithelial soluble factors. Pre-treatment of stromal cells with TGF-β1 enhanced this migratory stimulus by elevating NOX4 expression and intracellular ROS production. TGF-β1 seems to be a major component of the epithelial soluble factors that stimulate NOX4 expression.Conclusions:Our results have identified that an increased stromal oxidative status, mainly provided by an elevated NOX4 expression, is a permissive element in the acquisition of epithelial migratory properties. The capacity of stromal cells to modify their intracellular ROS production, and accordingly, to increase epithelial motility, seems to depend on epithelial soluble factors among which TGF-β1 have a decisive role.

Chitosan is a naturally derived polymer with antimicrobial and anti-inflammatory properties. However, studies evaluating the role of chitosan in the control of periodontal pathogens and the responses of fibroblasts to inflammatory stimuli are lacking. In the present study, we analyzed whether chitosan particles may inhibit the growth of periodontal pathogens and modulate the inflammatory response in human gingival fibroblasts. Chitosan particles were generated through ionic gelation. They inhibited the growth of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans at 5 mg/mL. Conversely, IL-1β strongly stimulated PGE2 protein levels in gingival fibroblasts, and chitosan inhibited this response at 50 µg/mL. IL-1β-stimulated PGE2 production was dependent on the JNK pathway, and chitosan strongly inhibited this response. IL-1β stimulated NF-κB activation, another signaling pathway involved in PGE2 production. However, chitosan particles were unable to modify NF-κB signaling. The present study shows that chitosan exerts a predominantly anti-inflammatory activity by modulating PGE2 levels through the JNK pathway, which may be useful in the prevention or treatment of periodontal inflammation.

In carcinomas such as those of breast, pancreas, stomach, and colon, cancer cells support the expansion of molecular and cellular stroma in a phenomenon termed desmoplasia, which is characterized by a strong fibrotic response. In the case of breast tissue, in which stroma is mainly a fatty tissue, this response presumably occurs at the expense of the adipose cells, the most abundant stromal phenotype, generating a tumoral fibrous structure rich in fibroblast-like cells. In this study, we aimed to determine the cellular mechanisms by which factors present in the media conditioned by MDA-MB-231 and MCF-7 human breast cancer cell lines induce a reversion of adipose cells to a fibroblastic phenotype. We demonstrated that soluble factors generated by these cell lines stimulated the reversion of mammary adipose phenotype evaluated as intracellular lipid content and expression of C/EBP alpha and PPAR gamma. We also demonstrated that exogenous TGF-beta 1 and TNF-alpha exerts a similar function. The participation of both growth factors, components of media conditioned by tumoral mammary cells, on the expression and nuclear translocation of C/EBP alpha and PPAR gamma was tested in 3T3-L1 cells by interfering with the inhibitory effects of media with agents that block the TGF-beta 1 and TNF-alpha activity. These results allow us to postulate that TGF-beta 1 and TNF-alpha present in this media are in part responsible for this phenotypic reversion.

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