Plasma vitronectin concentrations in patients with chronic hepatitis C treated with interferon alpha

Vitronectin in the ascites of human ovarian carcinoma acts as a potent chemoattractant for ovarian carcinoma: Implication for metastasis by cancer stem cells

Vitronectin has been identified mainly as an adhesion protein that signals through uPAR and selected integrin receptors. In addition to its pro-adhesive properties, we identified recently vitronectin as a main chemoattractant present in diluted plasma/serum that directly stimulates migration of cancer cells. We also found that this pro-migratory activity of vitronectin can be quenched by fibrinogen. Based on this we hypothesized that this may explain preference of cancer cell to metastasize to fibrinogen-low microenvironments such as lymphatics or peritoneal cavity. Based on this, we decided to investigate a role of vitronectin in metastasis of ovarian cancer cells to peritoneal cavity. We tested migratory responsiveness of three human ovarian cancer cell lines to ascites isolated from ovarian cancer patients and characterize possible molecules involved in migration of ovarian cancer cells. The ascites samples were exposed to heat inactivation, proteinase K digested, dialyzed and charcoal stripped. We also performed cut-off filtration analysis and by employing ELISA assays to measure concentration of vitronectin in ascites fluid samples. Finally, we employed shRNA against uPAR and small molecular inhibitors of integrin receptors to assess their involvement in biological effects of vitronectin. From our studies, we found that the similarly to diluted plasma, vitronectin in absence of fibrinogen is a main chemotactic/chemokinetic protein present in ascites fluid. We also found that these pro-migratory properties of vitronectin can be quenched by addition of fibrinogen. Our studies also indicate that both uPAR and integrin receptors on ovarian cancer cells regulate migration of these cells to vitronectin gradient. In summary, we identified free soluble vitronectin as a potent direct chemoattractant for ovarian cancer cells and that its activity is suppressed after binding to fibrinogen. Since in ascites fluids vitronectin is present in free form because of a lack or low level of fibrinogen, this could explain preferences of ovarian cancer stem cells to metastasize within peritoneum. We propose that inhibitors which could sequester soluble vitronectin in similar fashion as fibrinogen, could be employed as a novel anti-metastatic drugs.

Low levels of serum vitronectin associated with clinical phases in patients with hemorrhagic fever with renal syndrome

beta(3) integrin has been identified as a cellular receptor for Hantaan virus which causes hemorrhagic fever with renal syndrome (HFRS). As one of the ligands of beta(3) integrin, vitronectin (VN) may be altered in HFRS. In this study, changes of serum VN levels were determined in 112 patients with HFRS and 30 age- and sex-matched healthy controls by quantitative sandwich enzyme immunoassay. The levels of serum VN were analyzed in patients at various phases of HFRS and with different severity of clinical types. Serum VN levels in patients with HFRS, at all clinical phases except the convalescent phase, were significantly decreased compared with those in the controls (P < 0.01). The serum levels of VN decreased at febrile phase, maintained at the lowest status during hypotensive and oliguric phases, started to increase from polyuric phase and reached almost normal condition till convalescent phase. The levels of serum VN between patients with milder and more severe clinical types showed no significant difference at each phase (P > 0.05). These results suggest that VN level was altered during the course of HFRS and chronological changes of serum levels of VN may correlate with the evolution of the disease.