Evidence for increased expression of tissue factor and protease-activated receptor-1 in human esophageal cancer.

It has been suggested that the blood clotting initiator protein, tissue factor (TF), participates in tumor growth, metastasis and angiogenesis. In addition, a family of G protein-coupled-receptors known as protease-activated receptors (PARs) has also been implicated in tumor biology. These receptors might be activated by blood coagulation proteases thus eliciting a number of pro-tumoral responses, including the expression of interleukin-8 (IL-8). Therefore, in this study we analyzed the expression of TF, PAR-1, PAR-2 and IL-8 genes in patients with esophageal cancer, one of the most aggressive neoplastic diseases. Total RNA was extracted from tissue samples (tumor and the corresponding normal mucosa) obtained from patients submitted to esophagectomy or endoscopy and further analyzed by semi-quantitative reverse transcriptase-polymerase (RT-PCR) and/or real-time quantitative PCR (qPCR). Expression of full-length transmembrane TF was significantly higher in tumor samples whereas no differences were observed in alternatively spliced TF transcripts. Tumor tissue showed increased mRNA levels for PAR-1 but not PAR-2. Remarkably, IL-8 expression was not detected in most normal tissues but showed very high expression in tumor samples. As expected, qPCR revealed greater differences in the expression pattern of all transcripts analyzed but the general profile was very similar to that observed by RT-PCR. Altogether our data suggest a possible role for blood clotting proteins in the biology of human esophageal cancer.

RGD- and MLD-disintegrins, jarastatin and EC3, activate integrin-mediated signaling modulating the human neutrophils chemotaxis, apoptosis and IL-8 gene expression.

The effects of jarastatin (JT), a monomeric RGD-disintegrin, were compared with those of the heterodimeric MLD-disintegrin, EC3, on human neutrophil activation and functions. Both disintegrins inhibited neutrophil chemotaxis induced by fMet-Leu-Phe and were also potent chemotactic agents. These effects were accompanied by an increase in actin polymerization, and both were inhibited by genistein, a tyrosine kinase inhibitor. While JT, but not other RGD-disintegrins, inhibited EC3-induced chemotaxis, EC3 was not able to inhibit JT effect. The chemotactic effect of JT was blocked by anti-alpha(M) antibody whereas anti-alpha(9)beta(1) inhibited EC3 effect. Both JT and EC3 induced focal adhesion kinase (FAK) and phosphoinositide 3-kinase (PI3K) activation. Accordingly, LY294002, a PI3K inhibitor, impaired their chemotactic effect on neutrophils. JT induced Erk-2 translocation to nucleus and a delay of the spontaneous apoptosis of neutrophils in vitro. In contrast, EC3 inhibited Erk-2 activation and had a proapoptotic effect. These effects were reverted by PD98059, an MEK 1/2 inhibitor and blocked by z-VAD-FMK, a caspase inhibitor. In addition, JT, but not EC3, increased the IL-8 mRNA levels in neutrophils. The data indicate that JT and EC3 directly activate an integrin-coupled signaling and modulate the MAPK pathway in different ways, leading the neutrophils to express different functional response.