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.

Anti-leishmanial activity of Avicennia marina (Avicenniaceae family) leaves hydroalcoholic extract and its possible cellular mechanisms.

Natural products are the main source of potent antioxidants and anti-leishmanial agents. This study was aimed to evaluate Avicennia marina (Avicenniaceae family) extract inhibitory effect against Leishmania tropica by accessing apoptotic markers and arginase activity. The A. marina were extracted and phytochemical analysis conducted. The inhibitory effect of A. marina was evaluated on L. tropica promastigote and amastigote forms, compared to meglumine antimoniate (Glucantime, MA) as standard drug. The level of apoptosis, Reactive Oxygen Species (ROS) production and arginase activity was assessed in A. marina-treated cells compared to control group. Phytochemical screening of A. marina extract showed strong presence of tannins and saponins. We demonstrated the inhibitory effect of A. marina on promastigote stages in a dose dependent manner. Also, lower 50% inhibitory concentration (IC50) value of amastigotes was indicated in A. marina group compared with the standard group of Glucantime (60.57 ± 1.46 vs. 73.19 ± 10.12 µg/mL, respectively, P < 0.05). Besides, A. marina represented no cytotoxicity as the selectivity index (SI) was 10.7. Also, it showed the potential to induce early apoptosis of 46.5% in promastigotes at 125 µg/mL concentration. Significant reduction of arginase level was observed in both A. marina-treated cells and promastigotes. The promising results indicated higher effectiveness of A. marina in decreasing parasite growth, inducing apoptosis in promastigotes, increasing ROS production and decreasing arginase level. So, A. marina can be a native plant candidate for anti-leishmanial drug in tropical regions with cutaneous leishmaniasis due to L. tropica.

Molecular Characterization of Cryptosporidium spp. Isolated From Immunocompromised Patients and Children.

BACKGROUND: Cryptosporidium is known to be one of the most important causes of diarrhea in children and immunocompromised patients. Genotype characterization of Cryptosporidium species in each region would help in the treatment of this disease, as well as to locate the source of infection and to prevent the disease. OBJECTIVES: This current research was conducted in order to analyze the molecular characterization of isolated Cryptosporidium spp. in the Southwest of Iran. MATERIALS AND METHODS: In this survey, 390 fecal samples were collected from immunocompromised individuals and children under five-years-of-age. Parasitic infection was evaluated using wet mount preparation, formalin ether, a modified acid fast staining method and microscopic examination. Finally, a PCR-RFLP assay was performed on the extracted DNA collected from fecal samples that were positive for Cryptosporidium by the acid fast method. RESULTS: Among the 390 fecal samples, 16 cases (4.1%) were infected with Cryptosporidium. Molecular and genotype characterization found the following protozoan species; 11 Cryptosporidium parvum (68.8%), 4 C. hominis (25%), and one case of C. meleagridis (6.2%). CONCLUSIONS: The present study emphasized the public health importance of Cryptosporidium spp. in the study area. In addition, it seems that zoonotic species are the most important causes of infection in the region. As far as we are aware this the first report of a C. meleagridis infection in Iran.