Pedro Cortes-Reynosa

Coffee attenuates fibrosis by decreasing the expression of TGF-β and CTGF in a murine model of liver damage

This study was performed to evaluate the antifibrotic properties of coffee in a model of liver damage induced by repeated administration of thioacetamide (TAA) in male Wistar rats. In this study, cirrhosis was induced by chronic TAA administration and the effects of co‐administration of conventional caffeinated coffee or decaffeinated coffee (CC, DC, respectively) for 8 weeks were evaluated. TAA administration elevated serum alkaline phosphatase (AP), γ‐glutamyl transpeptidase (γ‐GTP) and alanine aminotransferase (ALAT), liver lipid peroxidation, collagen content, depleted liver glycogen and glutathione peroxidase (GPx) activity. Additionally increased levels of a number of proteins were detected including transforming growth factor‐beta (TGF‐β), connective tissue growth factor (CTGF) and alpha‐smooth muscle actin (α‐SMA), and matrix metalloproteinase (MMP)‐2, 9 and 13. Coffee suppressed most of the changes produced by TAA. Histopathological analysis was in agreement with biochemical and molecular findings. These results indicate that coffee attenuates experimental cirrhosis; the action mechanisms are probably associated with its antioxidant properties and mainly by its ability to block the elevation of the profibrogenic cytokine TGF‐β and its downstream effector CTGF. Various components of coffee that have been related to such a favorable effect include caffeine, coffee oils kahweol, cafestol and antioxidant substances; however, no definite evidence for the role of these components has been established. These results support earlier findings suggesting a beneficial effect of coffee on the liver. However, more basic clinical studies must be performed to confirm this hypothesis. Copyright

Linoleic acid induces an EMT-like process in mammary epithelial cells MCF10A

Epidemiological studies and animal models suggest an association between high levels of dietary fat intake and an increased risk of developing breast cancer. Epithelial-mesenchymal-transition (EMT) is a process, by which epithelial cells are transdifferentiated to a mesenchymal state, and it has been implicated in cancer progression, including invasion and metastasis. Linoleic acid (LA) induces proliferation and invasion in breast cancer cells. However, the role of LA on the EMT process in human mammary epithelial cells remains to be studied. In the present study, we demonstrate that LA induces a transient down-regulation of E-cadherin expression, accompanied with an increase of Snail1, Snail2, Twist1, Twist2 and Sip1 expressions. Furthermore, LA induces FAK and NFκB activation, MMP-2 and -9 secretions, migration and invasion. In summary, our findings demonstrate, for the first time, that LA promotes an EMT-like process in MCF10A human mammary epithelial cells.

Role of DDR1 in the gelatinases secretion induced by native type IV collagen in MDA-MB-231 breast cancer cells

Discoidin domain receptors (DDRs) are receptor tyrosine kinases that get activated by collagens in its native triple-helical form. In mammalian cells, DDR family consists of two members, namely DDR1 and DDR2, which mediates migration and proliferation of several cell types. DDR1 is activated by native type IV collagen and overexpressed in human breast cancer. Type IV collagen is the main component of basement membrane (BM), and the ability to degrade and penetrate BM is related with an increased potential for invasion and metastasis. Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that collectively are capable of degrading all components of the extracellular matrix, including the BM. In breast cancer cells, denatured type IV collagen induces MMP-9 secretion and invasion. However, the role of DDR1 in the regulation of gelatinases (MMP-2 and -9) secretion and invasion in breast cancer cells remains to be studied. We demonstrate here that native type IV collagen induces MMP-2 and -9 secretions and invasion through a DDR1 and Src-dependent pathway, together with an increase of MMP-2 and -9-cell surface levels. MMP-2 and -9 secretions require PKC kinase activity, epidermal growth factor receptor (EGFR) activation, arachidonic acid (AA) production and AA metabolites in MDA-MB-231 breast cancer cells. In summary, our data demonstrate, for the first time, that DDR1 mediates MMP-2 and -9 secretions and invasion induced by native type IV collagen in MDA-MB-231 breast cancer cells.

Arachidonic acid promotes migration and invasion through a PI3K/Akt-dependent pathway in MDA-MB-231 breast cancer cells

Arachidonic acid (AA) is a common dietary n-6 cis polyunsaturated fatty acid that under physiological conditions is present in an esterified form in cell membrane phospholipids, however it might be present in the extracellular microenvironment. AA and its metabolites mediate FAK activation, adhesion and migration in MDA-MB-231 breast cancer cells. However, it remains to be investigated whether AA promotes invasion and the signal transduction pathways involved in migration and invasion. Here, we demonstrate that AA induces Akt2 activation and invasion in MDA-MB-231 cells. Akt2 activation requires the activity of Src, EGFR, and PIK3, whereas migration and invasion require Akt, PI3K, EGFR and metalloproteinases activity. Moreover, AA also induces NFκB-DNA binding activity through a PI3K and Akt-dependent pathway. Our findings demonstrate, for the first time, that Akt/PI3K and EGFR pathways mediate migration and invasion induced by AA in MDA-MB-231 breast cancer cells.

Linoleic acid induces migration and invasion through FFAR4- and PI3K-/Akt-dependent pathway in MDA-MB-231 breast cancer cells

An increased risk of developing breast cancer has been associated with high levels of dietary fat intake. Linoleic acid (LA) is an essential fatty acid and the major ω-6 polyunsaturated fatty acid in occidental diets, which is able to induce inappropriate inflammatory responses that contribute to several chronic diseases including cancer. In breast cancer cells, LA induces migration. However, the signal transduction pathways that mediate migration and whether LA induces invasion in MDA-MB-231 breast cancer cells have not been studied in detail. We demonstrate here that LA induces Akt2 activation, invasion, an increase in NFκB–DNA binding activity, miR34a upregulation and miR9 downregulation in MDA-MB-231 cells. Moreover, Akt2 activation requires EGFR and PI3K activity, whereas migration and invasion are dependent on FFAR4, EGFR and PI3K/Akt activity. Our findings demonstrate, for the first time, that LA induces migration and invasion through an EGFR-/PI3K-/Akt-dependent pathway in MDA-MB-231 breast cancer cells.

Epidermal Growth Factor Promotes Epidermal Growth Factor Receptor Nuclear Accumulation by a Pathway Dependent on Cytoskeleton Integrity in Human Breast Cancer Cells

BACKGROUND AND AIMS The epidermal growth factor receptor (EGFR) is activated by extracellular ligands of the epidermal growth factor (EGF) family, resulting in a cascade of cytoplasmic signaling events. Emerging evidence indicates a mode of EGF signaling in which growth factor signals are transmitted via EGFR nuclear transport. The aim of this study was to determine whether EGF promotes EGFR nuclear accumulation and the role of clathrin-coated pits, EGFR kinase activity, caveolae microdomains and cytoskeleton integrity in breast cancer cells. METHODS MCF-7 cells were treated without or with 100 ng/ml EGF for various times and nuclear extracts were obtained. Nuclear accumulation of EGFR was analyzed by SDS-PAGE followed by Western blotting of nuclear extracts using an anti-EGFR Ab or with a phosphospecific Ab against the Tyr-1068 of EGFR and with anti-Rb Ab as the loading control. DNA binding activity of EGFR was analyzed by EMSA using nuclear extracts and a radiolabeled oligonucleotide probe representing the AT-rich minimal sequence (ATRS). RESULTS EGF induces the nuclear accumulation of EGFR, an increase in EGFR phosphorylation at Tyr-1068 and the formation of the complex EGFR-DNA in MCF-7 and MDA-MB-231 breast cancer cells. In addition, EGFR nuclear accumulation is dependent of clathrin-coated pits, EGFR kinase activity, caveolae microdomains and cytoskeleton integrity. CONCLUSIONS This study demonstrates that in breast cancer cells EGF promotes nuclear accumulation of EGFR and is dependent on clathrin-coated pits, EGFR kinase activity, caveolae microdomains and cytoskeleton integrity.

Extracellular vesicles from women with breast cancer promote an epithelial-mesenchymal transition-like process in mammary epithelial cells MCF10A

Extracellular vesicles (EVs) mediate many stages of tumor progression including angiogenesis, escape from immune surveillance, and extracellular matrix degradation. We studied whether EVs from plasma of women with breast cancer are able to induce an epithelial-mesenchymal transition (EMT) process in mammary epithelial cells MCF10A. Our findings demonstrate that EVs from plasma of breast cancer patients induce a downregulation of E-cadherin expression and an increase of vimentin and N-cadherin expression. Moreover, EVs induce migration and invasion, as well as an increase of NFκB-DNA binding activity and MMP-2 and MMP-9 secretions. In summary, our findings demonstrate, for the first time, that EVs from breast cancer patients induce an EMT-like process in human mammary non-tumorigenic epithelial cells MCF10A.

Role of arachidonic acid metabolism in Stat5 activation induced by oleic acid in MDA-MB-231 breast cancer cells.

Epidemiological studies and animal models suggest an association between high levels of dietary fat intake and an increased risk of breast cancer. In breast cancer cells, the free fatty acid oleic acid (OLA) induces proliferation, migration, invasion and an increase of MMP-9 secretion. However, the role of OLA on Stat5 activation and the participation of COX-2 and LOXs activity in Stat5 activation induced by OLA remain to be investigated. We demonstrate here that stimulation of MDA-MB-231 breast cancer cells with 100 μM OLA induces Stat5 phosphorylation at Tyr-694 and an increase of Stat5-DNA complex formation. The Stat5 DNA-binding activity requires COX-2, LOXs, metalloproteinases and Src activities. In addition, OLA induces cell migration through a Stat5-dependent pathway. In summary, our findings establish that OLA induces cell migration through a Stat5-dependent pathway and that Stat5 activation requires AA metabolites in MDA-MB-231 breast cancer cells.

The invasiveness of human cervical cancer associated to the function of Na V 1.6 channels is mediated by MMP-2 activity

Voltage-gated sodium (NaV) channels have been related with cell migration and invasiveness in human cancers. We previously reported the contribution of NaV1.6 channels activity with the invasion capacity of cervical cancer (CeCa) positive to Human Papilloma Virus type 16 (HPV16), which accounts for 50% of all CeCa cases. Here, we show that NaV1.6 gene (SCN8A) overexpression is a general characteristic of CeCa, regardless of the HPV type. In contrast, no differences were observed in NaV1.6 channel expression between samples of non-cancerous and cervical intraepithelial neoplasia. Additionally, we found that CeCa cell lines, C33A, SiHa, CaSki and HeLa, express mainly the splice variant of SCN8A that lacks exon 18, shown to encode for an intracellularly localized NaV1.6 channel, whereas the full-length adult form was present in CeCa biopsies. Correlatively, patch-clamp experiments showed no evidence of whole-cell sodium currents (INa) in CeCa cell lines. Heterologous expression of full-length NaV1.6 isoform in C33A cells produced INa, which were sufficient to significantly increase invasion capacity and matrix metalloproteinase type 2 (MMP-2) activity. These data suggest that upregulation of NaV1.6 channel expression occurs when cervical epithelium have been transformed into cancer cells, and that NaV1.6-mediated invasiveness of CeCa cells involves MMP-2 activity. Thus, our findings support the notion about using NaV channels as therapeutic targets against cancer metastasis.

Migration and invasion induced by linoleic acid are mediated through fascin in MDA-MB-231 breast cancer cells

Epidemiological studies strongly suggest an association between high levels of dietary fat intake and an increased risk of developing breast cancer. Linoleic acid (LA) is an essential omega-6 PUFA and the major fatty acid in occidental diets. In breast cancer cells, LA induces expression of plasminogen activator inhibitor-1, proliferation, migration, and invasion. Fascin is an actin crosslinker globular protein that generates actin bundles made of parallel actin filaments, which mediate formation and stability of microspikes, stress fibers, membrane ruffles, and filopodia. However, the role of fascin in migration and invasion induced by LA in MDA-MB-231 breast cancer cells remains to be studied. We demonstrate here that LA induces an increase of fascin expression in MDA-MB-231 and MCF12A mammary epithelial cells. Particularly, LA induces the formation of filopodia and lamellipodia and the localization of fascin in these actin structures in MDA-MB-231 breast cancer cells. However, LA only induces formation of microspikes and the localization of fascin in these actin structures in mammary non-tumorigenic epithelial cells MCF12A. In addition, LA induces migration, invasion, and matrix metalloproteinase-9 secretion through a fascin-dependent pathway in MDA-MB-231 cells. In summary, our findings demonstrate that fascin is required for migration and invasion induced by LA in MDA-MB-231 breast cancer cells.