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CD151/Tspan24 (SFS-1, PETA3) is one of the best characterized members of the tetraspanin family, whose involvement in breast cancer (BCa) progression was demonstrated both in vitro and in vivo. We have recently reported that in ErbB2-overexpressing BCa cells grown in 3D laminin-rich extracellular matrix, CD151 regulated basal phosphorylation and homodimerization of ErbB2 and sensitized the cells to Herceptin (trastuzumab). Following from these data, we have here analyzed an involvement of CD151 in regulation of ErbB2/ErbB3 heterodimerization and its impact on cell response to Herceptin. CD151 was found to: (1) impair ErbB2/ErbB3 heterodimerization, (2) inhibit heregulin-dependent cell growth in 3D and signaling, and (3) counteract the protective effect of heregulin on Herceptin-mediated growth inhibition. Analysis of tissue samples demonstrated for the first time clinical significance of CD151 in patients with ErbB2-overexpressing BCa undergone trastuzumab-based therapy. Consistent with in vitro results, CD151 impact on disease outcome was ErbB3-dependent. In patients with ErbB3-negative tumors, CD151 significantly improved both overall survival (OS) (hazard ratio [HR] = 0.19, P = 0.034) and progression-free survival (PFS) (HR = 0.36, P = 0.043), while in ErbB3-positive cases it had no significant effect on patient survival (OS: HR = 3.33, P = 0.283; PFS: HR = 2.40, P = 0.208). These results support previous findings and show that CD151 acts as an important component of ErbB2 signaling axis in BCa cells, affecting their sensitivity to ErbB2-targeting therapy. [ABSTRACT FROM AUTHOR]

Creatine kinase (CK, ATP creatine phosphotransferase, EC 2.7.3.2) is an enzyme participating in ATP regeneration, which is the primary source of energy in living organisms. We demonstrated that CK from herring spermatozoa has high activity (∼452 μmol/min/g of fresh semen) and has a different electrophoretic mobility from isoenzymes present in skeletal muscle. In our study, we investigated toxic effect of tributyltin (TBT) on herring spermatozoa using a specific sperm viability kit to observe live and dead sperm cells with a confocal microscope. Treatment of herring spermatozoa with TBT caused a time-dependent decrease of viability: 35% nonviable cells with 5 μM TBT and more than 90% nonviable cells with 10 μM TBT after 6 h exposure. We also monitored CK release from damaged spermatozoa into surrounding medium containing different concentrations of TBT. The higher concentration of TBT was used the more CK release from spermatozoa was observed. We suggest that CK could be a good biomarker of sperm cell membranes degradation in the case when lactate dehydrogenase release from permeabilized cells is not possible for rapid determination of the effect of TBT. [Copyright &y& Elsevier]

Autophagy is an intracellular defense mechanism responsible for the turnover of damaged or non-functional cellular constituents. This process provides cells with energy and essential compounds under unfavorable environmental conditions—such as oxidative stress and hyperglycemia, which are both observed in diabetes. The most common diabetes complication is diabetic nephropathy (DN), which can lead to renal failure. This condition often includes impaired podocyte function. Here we investigated autophagic activity in rat podocytes cultured with a high insulin concentration (300 nM). Autophagy was activated after 60 min of insulin stimulation. Moreover, this effect was abolished following pharmacological (apocynin) or genetic (siRNA) inhibition of NAD(P)H oxidase activity, indicating that insulin-dependent autophagy stimulation involved reactive oxygen species (ROS). We also observed a continuous and time-dependent increase of podocyte albumin permeability in response to insulin, and this process was slightly improved by autophagy inhibition following short-term insulin exposure. Our results suggest that insulin may be a factor affecting the development of diabetic nephropathy. [ABSTRACT FROM AUTHOR]

Abstract: A novel compound—2″,3″,4″,6″-tetra-O-acetyl-β-d-galactopyranosyl-(1→4)-2′,3′,6′-tri-O-acetyl-1-thio-β-d-glucopyranosyl-(5-nitro-2-pyridyl) sulfoxide—designated GP6 was synthesized and assayed for cytotoxicity and in vitro antiviral properties against classical swine fever virus (CSFV) in this study. We showed that the examined compound effectively arrested CSFV growth in swine kidney cells (SK6) at a 50% inhibitory concentration (IC50) of 5±0.12μg/ml without significant toxicity for mammalian cells. Moreover, GP6 reduced the viral E2 and Erns glycoproteins expression in a dose-dependent manner. We have excluded the possibility that the inhibitor acts at the replication step of virus life cycle as assessed by monitoring of RNA level in cells and culture medium of SK6 cells after single round of infection as a function of GP6 treatment. Using recombinant Erns and E2 proteins of classical swine fever virus produced in baculovirus expression system we have demonstrated that GP6 did not influence glycoprotein production and maturation in insect cells. In contrast to mammalian glycosylation pathway, insect cells support only the ER-dependent early steps of this process. Therefore, we concluded that the late steps of glycosylation process are probably the main targets of GP6. Due to the observed antiviral effect accompanied by low cytotoxicity, this inhibitor represents potential candidate for the development of antiviral agents for anti-flavivirus therapy. Further experiments are needed for investigating whether this compound can be used as a safe antiviral agent against other viruses from unrelated groups. [Copyright &y& Elsevier]