Neutral endopeptidase (NEP) inhibitors - thiorphan, sialorphin, and its derivatives exert anti-proliferative activity towards colorectal cancer cells in vitro.

Neutral endopeptidase (NEP) is an enzyme implicated in development of different tumors, e.g. colorectal cancer (CRC). In this study, the anti-cancer effects of NEP inhibitors, thiorphan (synthetic compound) and sialorphin (naturally occurring pentapeptide) on CRC cells were investigated. Moreover, we synthesized some derivatives of sialorphin (alanine scan analogues: AHNPR, QANPR, QHAPR, QHNAR; N-acetylated sialorphin; C-amidated sialorphin, and C-amidated alanine scan analogues) to examine the biological activity of these inhibitors on CRC cells. The cytotoxic activity of the NEP inhibitors against CRC cell lines (SW620 and LS180) and normal human fibroblasts (HSF) was evaluated. Additionally, the influence of NEP inhibitors on proliferation, cell cycle progression, induction of apoptosis, and the level of phosphorylation of MAP kinases and mTORC1 signaling pathway proteins in CRC cells were examined. The NEP inhibitors were non-cytotoxic to HSF cells; however, most of them slightly decreased the viability and inhibited proliferation of CRC cells. The N-acetylation or C-amidation of sialorphin or its alanine scan analogues resulted in decreased or abolished anti-proliferative activity of the NEP inhibitors towards the CRC cells. Additionally, thiorphan and sialorphin enhanced the anti-proliferative activity of other CRC-cell growth inhibitors (atrial natriuretic peptide-ANP and melphalan-MEL). The mechanisms involved in the anti-proliferative effects of the tested inhibitors were mediated via NEP and associated with induction of cell cycle arrest in the G0/G1 phase, increased activity of ERK1/2, and a reduced level of phosphorylation of mTOR (Ser2448), 4E-BP1, and p70S6K. However, the NEP inhibitors did not induce apoptosis in the CRC cells. These results have indicated that thiorphan and sialorphin or its derivatives AHNPR, QANPR, QHAPR, and QHNAR have the potential to be used as agents in treatment of patients with CRC.

Artificial (137)Cs and (134)Cs and natural (40)K in sclerotia of Wolfiporia extensa fungus collected across of the Yunnan land in China.

Dried sclerotia of Wolfiporia extensa has a long history of medicinal and grocery uses in Asia and elsewhere. This study aimed at providing and evaluating data on activity concentrations from artificial (137)Cs and (134)Cs radionuclides and natural (40)K in sclerotia collected across of the Yunnan land in China, which is generally lacking information. Sclerotia of W. extensa showed a low contamination with (137)Cs while (134)Cs was below limit of quantification. Estimated, the nominal value of effective dose (µSv) received by adult eating annually 50 g of the 'average' Yunnan's origin sclerotia contained in the 'Fuling jiabing' snack due to (137)Cs could be between < 0.00091 and 0.0047 ± 0.0007 µSv per capita and at < 0.000015 to 0.000078 ± 0.000012 µSv per kg of body mass, which is a very low exposure. This study has revealed also that sclerotia of W. extensa are characterized by very low content of (40)K (hence also of total K) when compared to fruiting bodies of many saprobic and mycorrhizal mushrooms.

Synthesis of α-collagen fragments and research of their influence on the degree of hydration of a model of epidermis.

INTRODUCTION: In recent years the interest into areas of science, such as cosmetology, dermatology, pharmacology or aesthetic medicine has increased significantly. Scientists are more frequently looking for ingredients that affect the skin's condition and slow down the aging process. Practically every year, the scientists discover a number of new chemical substances (both natural and synthetic) that can be potentially used to manufacture cosmetics. AIM: To evaluate the influence of selected peptides derived from α-collagen fragments on the degree of hydration of a model of epidermis isolated from a pig. MATERIAL AND METHODS: The synthesis of selected cosmetic oligopeptides were performed manually, on the solid medium, using procedure of SPPS (solid phase peptide synthesis). Following components: aqua, carbomer, glycerine, phenonip, D-panthenol, dimethicone and triethanolamine were used to prepare a reference hydrogel masks. Both the number of components and the composition of hydrogels have been developed individually for the purposes of this research. For this study the skin from a domestic pig was used. The degree of the skin hydration was measured with the SKINTEST plus camera, which uses the latest semiconductor technology. RESULTS: During the study the absorption of hydrogels with peptides was faster than that of the reference hydrogel mask. The combination of hydrophilic properties of the peptide with hydrophobic properties of Palm enabled receiving an amphiphilic structure. Such molecules are considered to be able to penetrate the corneum barrier with the greatest ease. CONCLUSIONS: The results showed that the modified compounds have contributed to water retention in the cells, thereby increasing the degree of hydration of the biological material.

Hypertensive activity of synthesized PTH(25-34) and Ac-PTH(25-30)-NH2 in rats.

Parathyroid hormone (PTH) is secreted by parathyroid glands and is the main known factor that control plasma calcium concentration. There are many indications that PTH or products of PTH degradation influence the mean arterial blood pressure (MAP). These observations might be important in diseases accompanied with the overproduction of PTH such as primary hyperparathyroidism (PHPT). It was shown that the six amino acids PTH precursor-PRO-PTH with reversed sequence (PRO-rs), which contains a rare tripeptide -Arg-Lys-Lys- fragment, induces significant hypertensive response in rats. This strong alkali tripeptide is also present in the position 25-27 of the PTH molecule. The aim of the present study was to synthesize, by the solid phase peptide synthesis method, PTH fragments including the -Arg-Lys-Lys- sequence and test their influence on blood pressure and calcium plasma concentration in rats. Our study demonstrated that PTH(25-34) and the acetylated amide analogue of PTH(25-30), (Ac-PTH(25-30)-NH(2)) were hypertensive in the physiological doses. The presence of strong alkali sequence -Arg-Lys-Lys- in PTH(25-30) fragment is not sufficient to induce hypertension either in physiological or pharmacological doses in rats. Therefore, both the proximity of the -Arg-Lys-Lys- sequence and length of the peptide might also play roles as pressure factors.

Discriminating between serological responses to European-genotype live vaccine and European-genotype field strains of porcine reproductive and respiratory syndrome virus (PRRSV) by peptide ELISA.

A peptide ELISA was developed based on an immunodominant and hypervariable epitope in the ORF4 envelope glycoprotein of porcine reproductive and respiratory syndrome virus (PRRSV). The peptide sequence was derived from the Porcilis live-attenuated PRRSV vaccine strain (genotype 1, European). Antibodies induced by the field PRRSVs currently circulating in Poland were not detected by the Porcilis ORF4 peptide ELISA. In contrast, Porcilis-vaccinated animals seroconverted in the ORF4 peptide ELISA at 21 days post-vaccination. Maximal titers were seen 30-92 days post-vaccination; most sera had endpoint titers between 1:1000 and 1:100,000. In a paired format, where sera were assayed in two separate ELISAs using ORF4 peptides derived from the genetically very closely related Porcilis and Lelystad PRRSV strains, it was possible to differentiate between antibodies induced by these two viruses. The Porcilis and Lelystad ORF4 peptide ELISAs had sensitivities of 89 and 100%, respectively. Thus, ORF4 peptide ELISA afforded specific detection of antibodies induced by an European-genotype live-attenuated vaccine PRRSV strain (Porcilis). The results suggest that specific ORF4 peptide ELISAs can be custom-made for European-genotype PRRSV strains, using general peptide design criteria described in this work. Thus, ORF4 ELISAs may be generally useful, to monitor safety and operational aspects of European-genotype live-attenuated PRRSV vaccine virus use in populations with circulating field European-genotype PRRSVs.

Human heat shock protein 60 (409-424) fragment is recognized by serum antibodies of patients with acute coronary syndromes.

Acute coronary syndromes (ACS), including unstable angina (UA) and acute myocardial infarction (MI), are clinical manifestations of a progressive atherosclerotic process. Antibodies (Ab) to heat shock proteins (hsp) have been reported to be associated with atherosclerosis. Blood samples from 35 patients with ACS and 20 healthy volunteers were tested for Ab to human hsp60 by an enzyme-linked immunosorbent assay (ELISA). Levels of specific serum Ab against hsp60 were significantly elevated in patients with ACS when compared to clinically healthy subjects. To determine the antigenic determinants recognized by these Ab, antibody binding to seven peptides, selected from the hydrophilic and acrophilic regions of the human hsp60 molecule, was assessed. Despite the individual variation in the immune response among patients, one immunodominant region was revealed corresponding to the hsp60 (409-424) peptide. The identification of this epitope may be important for understanding the function of this protein in the atherosclerotic process.

In vitro effect of short-term exposure to two synthetic peptides, alone or in combination with clarithromycin or rifabutin, on Cryptosporidium parvum infectivity.

The viability of Cryptosporidium parvum after exposure to peptide antibiotics was studied by two different methods, a cell culture system and a double fluorogenic staining. The peptides KFFKFFKFF and IKFLKFLKFL exerted high cytotoxic effects on sporozoites, as demonstrated by cell cultures (complete inhibition after 60 min at 100 microg/ml) and flow cytometry (30% after 20 min at 100 microg/ml), but did not affect consistently the oocysts. Clarithromycin and rifabutin demonstrated less activity against sporozoites but higher activity against oocysts (30% after 180 min at 10 microg/ml). The combination between peptides and azithromycin or rifabutin exerted the highest activities.

Therapeutic efficacy of intraperitoneal polymyxin B and polymyxin-like peptides alone or combined with levofloxacin in rat models of septic shock.

The efficacy of two polymyxin-like peptides, KFFKFFKFF and IKFLKFLKFL, alone and combined with levofloxacin, was investigated in a rat model of septic shock. Rats were given an ip injection of 2 x 10(10) cfu of Escherichia coli and randomized to receive ip isotonic sodium chloride solution, 7 mg/kg levofloxacin, 1 mg/kg polymyxin B and 1 mg/kg of each polymyxin-like peptides alone or combined with 7 mg/kg levofloxacin. Polymyxins achieved a significant reduction in plasma endotoxin and tumour necrosis factor alpha (TNF-alpha) concentration. Levofloxacin significantly reduced the bacterial growth and TNF-alpha concentration. The combinations of polymyxin-like peptides and levofloxacin demonstrated the highest efficacy.