Design of ion channel blocking, toxin-like Kunitz inhibitor peptides from the tapeworm, Echinococcus granulosus, with potential anti-cancer activity.

Over-expression of K+ channels has been reported in human cancers and is associated with the poor prognosis of several malignancies. EAG1, a particular potassium ion channel, is widely expressed in the brain but poorly expressed in other normal tissues. Kunitz proteins are dominant in metazoan including the dog tapeworm, Echinococcus granulosus. Using computational analyses on one A-type potassium channel, EAG1, and in vitro cellular methods, including major cancer cell biomarkers expression, immunocytochemistry and whole-cell patch clamp, we demonstrated the anti-tumor activity of three synthetic small peptides derived from E. granulosus Kunitz4 protease inhibitors. Experiments showed induced significant apoptosis and inhibition of proliferation in both cancer cell lines via disruption in cell-cycle transition from the G0/G1 to S phase. Western blotting showed that the levels of cell cycle-related proteins including P27 and P53 were altered upon kunitz4-a and kunitz4-c treatment. Patch clamp analysis demonstrated a significant increase in spontaneous firing frequency in Purkinje neurons, and exposure to kunitz4-c was associated with an increase in the number of rebound action potentials after hyperpolarized current. This noteworthy component in nature could act as an ion channel blocker and is a potential candidate for cancer chemotherapy based on potassium channel blockage.

Molecular and clinical profile of congenital fibrinogen disorders in Iran, identification of two novel mutations.

INTRODUCTION: Congenital fibrinogen disorders (CFDs) comprise the quantitative and qualitative fibrinogen molecule abnormalities that are caused by fibrinogen gene mutations. The objective of this cohort research was to study the molecular and clinical profiles of patients with CFDs. MATERIALS AND METHODS: Genomic DNA Sanger sequencing of 14 Iranian patients was performed to determine CFDs-causing mutations. The disorders were diagnosed by routine and specific (fibrinogen antigen and functional assay) coagulation tests, and clinical data were obtained from medical records. Molecular dynamics (MD) simulations were performed to investigate the effect of missense mutation on the protein structure. RESULTS: Thirteen out of 14 patients had afibrinogenemia while the remaining patient had dysfibrinogenemia. Umbilical cord bleeding was the most common clinical presentation (n: 9, ~70%) which led to the diagnosis of afibrinogenemia, while menorrhagia led to the diagnosis of dysfibrinogenemia. Six homozygous mutations were identified in afibrinogenemia: three previously described variants in FGA (p.Trp52Ter, p.Ser312AlafsTer109 and p.Gly316GlufsTer105), one in FBG (p.Gly430Asp), and two novel mutations in FGB (p.Gly430Arg) and FGG (p.His366ThrfsTer40), while the FGA (p.Arg38Thr) heterozygous mutation was identified in dysfibrinogenemia. MD simulation indicated that the FGA p. Arg38Thr mutation probably interferes with polymerization of fibrin monomers. CONCLUSIONS: In Iran, with its high rate of consanguinity, autosomal recessive afibrinogenemia with severe clinical presentations is relatively common due to heterogeneous molecular defects.