Inhibitory effect of Bowman-Birk protease inhibitor on autophagy in MDAMB231 breast cancer cell line.

BACKGROUND: Autophagy has an essential role in cellular energetic balance, cell cycle, and cell death, so the change in autophagy level is crucial in many human diseases such as cancer. Herbal medicine has been widely used to treat cancer. Bowman-Birk protease inhibitor (BBI), a protease inhibitor extracted from soybean, has antitumorigenic, anti-inflammatory, and anti-angiogenic activities. In this study, we evaluated the effect of BBI on the growth of breast cancer cell line and transcript level of autophagy and apoptosis-related genes. MATERIALS AND METHODS: BBI was purified from soybean by ion-exchange chromatography method. The viability of MDA-MB-231 cells that were treated with BBI was measured by MTT assay, and the transcript level of genes involved in autophagy and apoptosis was measured by real-time-polymerase chain reaction (PCR) technique. RESULTS: The results of BBI purification showed that 100 g of the ethanolic fraction yielded 300-mg BBI with more than 95% purity. MTT results revealed that BBI inhibited the cell growth of MDA-MB-231 cell line in a dose-dependent manner, with an IC50 of 200 µg/mL. The results of real-time reverse transcription-PCR exhibited that BBI altered the expression of Atg5, Beclin1, light chain 3-II, and sequestosome1 and increased the Bax/Bcl2 ratio in MDA-MB-231 cell line. CONCLUSION: According to our results, BBI could inhibit autophagy and induce apoptosis in MDA-MB-231 cell line. Thus, BBI may be used as a therapeutic drug in the treatment of breast cancer whether alone or with chemotherapeutic drugs.

Glycation affects differently the main soybean Bowman-Birk isoinhibitors, IBB1 and IBBD2, altering their antiproliferative properties against HT29 colon cancer cells.

Naturally-occurring serine protease inhibitors of the Bowman-Birk family, particularly abundant in legume seeds, exert their potential chemopreventive and/or therapeutic properties via protease inhibition. Processing of legume seeds, including soybeans, has been proposed as a major cause for their loss of bioactivity due to glycation. In order to assess how glycation affected the protease inhibitory activities of major soybean Bowman-Birk isoinhibitors (BBI) and their antiproliferative properties, IBB1 and IBBD2 were purified and subjected to glycation under controlled conditions using glucose at high temperature. Both soybean isoinhibitors showed remarkable heat stability. In the presence of glucose, IBBD2 lost most of its trypsin inhibitory activity while IBB1 maintains similar trypsin and chymotrypsin inhibitory activities as in the absence of sugar. Glycation patterns of both BBI proteins were assessed by MALDI-TOF spectrometry. Our results show that the glycation process affects IBBD2, losing partially its antiproliferative activity against HT29 colon cancer cells, while glycated-IBB1 was unaffected.

Effects of compounds from Passiflora edulis Sims f. flavicarpa juice on blood coagulation and on proteolytic enzymes.

Passion fruit (Passiflora edulis Sims f. flavicarpa) is popularly known for its sedative and calming properties and is consumed as a fresh fruit or as a juice. The clinical observation of blood incoagulability associated with excessive consumption of passion fruit juice, in a patient treated with warfarin, prompted the current study to investigate in vitro the presence of blood clotting inhibitors in Passiflora edulis Sims f. flavicarpa extract. After purification process, two compounds of distinct molecular weight and inhibitory action were better characterized. One is a trypsin inhibitor similar to inhibitors from Bowman-Birk family, named PeTI-I12, and other is a compound active in coagulation that prolongs aPTT and PT, but does not change TT. The aim of this study is to provide evidence that passion fruit extract's components play a role on hemostasis and therefore may be relevant in the handling of patients treated with anticoagulants or suffering hemorrhagic diseases.

Bowman-Birk inhibitor and genistein among soy compounds that synergistically inhibit nitric oxide and prostaglandin E2 pathways in lipopolysaccharide-induced macrophages.

Inflammation has an important role in the development of chronic diseases. In this study, we evaluated the anti-inflammatory properties of eight soybean bioactive compounds using lipopolysaccharide-induced RAW 264.7 macrophages. Genistein, daidzein, a mix of isoflavone glucosides, saponin A group glycosides (saponin A), saponin B group glycosides (saponin B), sapogenol B, Bowman-Birk inhibitor (BBI), lunasin, and pepsin-pancreatin glycinin hydrolysates were tested by measuring their ability to inhibit cyclooxygenase-2/prostaglandin E(2) (PGE(2)) and inducible nitric oxide synthase (iNOS)/nitric oxide (NO) inflammatory pathways. Of the eight soy bioactive compounds (SBCs) tested, BBI and sapogenol B resulted in the highest inhibition of pro-inflammatory responses at a concentration 10 times lower than the one used for the other compounds. Also, sapogenol B and genistein (molar ratio 1:1) synergistically inhibited NO and additively inhibited PGE(2). Saponin A group glycosides showed inhibition of the iNOS/NO pathway only, while pepsin-pancreatin glycinin hydrolysates enhanced induction and production of the four inflammatory responses. For the first time, synergistic interactions were observed between BBI and genistein inhibiting NO (92.7%) and PGE(2) (95.6%) production. An antagonistic interaction was observed between the saponin B group glycosides and sapogenol B. All interactions were further confirmed by isobolographic analysis. These findings demonstrated that some SBCs possess anti-inflammatory properties and therefore are important in modulating mammalian inflammation pathways which may lead to inhibition of some types of chronic disease. Furthermore, through their interaction they can modulate the inflammatory process.

Chronicles in drug discovery.

Chronicles in Drug Discovery features special interest reports on advances in drug discovery and development. This month we focus on the progress of the ongoing search for safe and effective chemopreventive agents. Chemoprevention is a strategy to decrease the risk of developing cancer by using agents that prevent or abrogate carcinogenic processes. Bowman- Birk inhibitor concentrate, budesonide, NCX-4016 and statins are all undergoing investigation in the clinical setting as potential chemopreventive agents for head and neck, lung, colon and breast cancers, respectively.

Protection against adverse biological effects induced by space radiation by the Bowman-Birk inhibitor and antioxidants.

This study was undertaken to evaluate the protective effects of the soybean-derived Bowman-Birk inhibitor (BBI), BBI concentrate (BBIC) and/or antioxidants against the adverse biological effects induced by space radiation in cultured human epithelial cells. The effects of BBI, BBIC and a combination of ascorbic acid, co-enzyme Q10, L-selenomethionine (SeM) and vitamin E succinate on proton and HZE-particle [high-energy (high E) nuclei of heavier (high atomic number, Z) elements] radiation-induced cytotoxicity in MCF10 human breast epithelial cells and a phenotypic change associated with transformation in HTori-3 human thyroid epithelial cells were assessed with a clonogenic survival assay and a soft agar colony formation assay. The results demonstrate that BBIC and antioxidants are effective in protecting against space radiation-induced cytotoxicity in MCF10 cells and BBI, BBIC and antioxidants are effective in protecting against a space radiation-induced phenotypic change associated with transformation of HTori-3 cells.

Effects of soybean trypsin inhibitor on hypopharyngeal gland protein content, total midgut protease activity and survival of the honey bee (Apis mellifera L.).

Insecticidal properties of protease inhibitors have been established in transgenic plants. In the wake of continuous research and rapid development of protease inhibitors it is important to assess possible effects on beneficial insects like the honey bee (Apis mellifera L.). In this study, newly emerged caged bees were fed pollen diets containing three different concentrations (0.1%, 0.5% and 1% w:w) of soybean trypsin inhibitor (SBTI). Hypopharyngeal gland protein content, total midgut proteolytic enzyme activity of these bees, and survival were measured. Bees fed 1% SBTI had significantly reduced hypopharyngeal gland protein content and midgut proteolytic enzyme activity. There were no significant differences between control, 0.1% and 0.5% SBTI treatments. Bees fed a diet containing 1% SBTI had the lowest survival, followed by 0.5% and 0.1%, over a 30-day period. We concluded that nurse bees fed a pollen diet containing at least 1% SBTI would be poor producers of larval food, potentially threatening colony growth and maintenance.

Suppressing effects of dietary supplementation of soybean trypsin inhibitor on spontaneous, experimental and peritoneal disseminated metastasis in mouse model.

The modifying effects of a Kunitz trypsin inhibitor (KTI) and a Bowman-Birk trypsin inhibitor (BBI), purified from soybean trypsin inhibitor, as dietary supplements on experimental and spontaneous pulmonary metastasis of murine Lewis lung carcinoma 3LL cells as well as peritoneal disseminated metastasis model in human ovarian cancer HRA cells were investigated in i.v., s.c. and i.p. injection models in mice. Seven groups of female C57BL/6 or nude mice were fed a basal diet (control group) or the basal diet supplemented with KTI or BBI (5, 15, or 50 g/kg). Here we show that, in an in vivo spontaneous metastasis assay, the diet supplementation with KTI (15 and 50 g/kg), but not with BBI, for 28 days immediately after s.c. tumor cell inoculation significantly inhibited the formation of lung metastasis in C57BL/6 mice in a dose-dependent manner. The inhibition of lung metastasis was not due to direct antitumor effects of KTI. In an in vivo experimental metastasis assay, the diet supplementation with KTI or BBI for 21 days after i.v. tumor cell inoculation did not reduce the number of lung tumor colonies. In addition, KTI (15 or 50 g/kg) treatment in a peritoneal disseminated metastasis model of HRA cells resulted in a 40% reduction in total tumor burden when compared with control animals. Immunoblot analysis revealed that KTI specifically reduced expression of uPA protein as well as phosphorylation of MAP kinase and PI3 kinase proteins in the cells stimulated with agonists (G-CSF for 3LL cells or TGF-beta1 for HRA cells). These results suggest that dietary supplementation of KTI more efficiently regulates the mechanism involved in the entry into vascular circulation of tumor cells (intravasation) than in extravasation during the metastatic process. KTI treatment may also be beneficial for ovarian cancer patients with or at risk for peritoneal disseminated metastasis; it greatly reduces tumor burden in part by inhibiting phosphorylation of MAP kinase and PI3 kinase, leading to suppression of uPA expression.

An alternative approach to depigmentation by soybean extracts via inhibition of the PAR-2 pathway.

The protease-activated receptor 2, expressed on keratinocytes but not on melanocytes, has been ascribed functional importance in the regulation of pigmentation by phagocytosis of melanosomes. Inhibition of protease-activated receptor 2 activation by synthetic serine protease inhibitors requires keratinocyte-melanocyte contact and results in depigmentation of the dark skinned Yucatan swine, suggesting a new class of depigmenting mechanism and agents. We therefore examined natural agents that could exert their effect via the protease-activated receptor 2 pathway. Here we show that soymilk and the soybean-derived serine protease inhibitors soybean trypsin inhibitor and Bowman-Birk inhibitor inhibit protease-activated receptor 2 cleavage, affect cytoskeletal and cell surface organization, and reduce keratinocyte phagocytosis. The depigmenting activity of these agents and their capability to prevent ultraviolet-induced pigmentation are demonstrated both in vitro and in vivo. These results imply that inhibition of the protease-activated receptor 2 pathway by soymilk may be used as a natural alternative to skin lightening.

Relative importance of phytohemagglutinin (lectin) and trypsin-chymotrypsin inhibitor on bean (Phaseolus vulgaris L) protein absorption and utilization by the rat.

The main objective of this work was to perform a comparative study of the antinutritional and/or toxic properties of phytohemagglutinin and trypsin-chymotrypsin inhibitor extracted from the seed of a commercial cultivar of edible bean used in Brazil. Bean proteins were extracted in acidic salt solution and fractionated by dialysis and centrifugation, then freeze-dried. The total freeze-dried bean extract and the globulin or albumin protein fraction were resuspended in distilled water and heated (100 degrees C, 30 min) for inactivation of hemagglutinin. Diets were prepared with unheated bean protein fractions and heated ones (100% trypsin inhibitor activity, but 0% phytohemagglutinin activity). As a result, the inhibition of growth and poor dietary protein utilization were observed in rats fed diets containing unheated bean protein fractions, but not in rats fed diets containing heated fractions. It was thus assumed that phytohemagglutinin is the main antinutritional and toxic factor that in dry bean (Phaseolus) protein and that trypsin inhibitor (Bowman-Birk type) did not interfere with rat growth.

Purification and primary structure determination of a Bowman-Birk trypsin inhibitor from Torresea cearensis seeds.

A Bowman-Birk-type trypsin inhibitor (TcTI) was purified from seeds of Torresea cearensis, a Brazilian native tree of the Papilionoideae sub-family of Leguminosae. Three forms of the inhibitor were separated by anion exchange chromatography. The major form with 63 amino acids was entirely sequenced; it shows a high structural similarity to the Bowman-Birk inhibitors from other Leguminosae. The putative reactive sites of the inhibitor are a lysine residue at position 15 and a histidine at position 42 as identified by alignment to related inhibitors, direct chemical modification and specific enzymatic degradation. Immunoprecipitation with antibodies raised in rats is reduced significantly if TcTI is complexed with chymotrypsin and, to a lesser degree, if complexed with trypsin. TcTI forms a ternary complex with trypsin and chymotrypsin. The binary complexes with trypsin or chymotrypsin were isolated by gel filtration. Dissociation constants of the complexes with trypsin, plasmin, chymotrypsin, and factor XIIa are 1, 36, 50, 1450 nM, respectively; human plasma kallikrein, human factor Xa, porcine pancreatic kallikrein and bovine thrombin are not inhibited. TcTI prolongs blood clotting time of the contact phase activation pathway by inhibition of FXIIa.

Preparation and production of a cancer chemopreventive agent, Bowman-Birk inhibitor concentrate.

We describe our studies to produce an extract of soybeans with anticarcinogenic activity that we believe will be useful as a human cancer chemopreventive agent for several different organs. The anticarcinogenic activity of the extract is thought to be due to chymotrypsin inhibitor activity, which is due to the Bowman-Birk protease inhibitor (BBI) present in the extract, termed BBI concentrate (BBIC). We describe the contents of BBIC, the ability of BBIC to inhibit malignant transformation in vitro in terms of its chymotrypsin inhibitor activity, and the results of long-term toxicity studies in which mice and rats were exposed to high levels of BBIC for long periods of time.

Intestinal transmission of macromolecules (BSA and FITC-dextran) in the neonatal pig: enhancing effect of colostrum, proteins and proteinase inhibitors.

The effects of colostrum and constituents/factors in colostrum which may influence intestinal macromolecular transmission in the newborn preclosure pig were investigated. Unsuckled piglets were given, by use of a stomach tube, bovine serum albumin (BSA) and fluorescein-isothiocyanate (FITC)-labelled dextran 70,000 (FITC-D) as markers together with colostrum or the factors under study. The serum levels of BSA and FITC-D 4 h after feeding were then determined as a measure of the transfer. It was found that the two colostrums tested, bovine and especially porcine, markedly enhanced the transmission of both BSA and FITC-D. Furthermore, increasing amounts of the model proteins, BSA and bovine IgG (50-200 mg/ml), significantly increased the transfer of FITC-D, whereas unlabelled dextran 70,000 given in similar amounts did not. Proteinase inhibitors obtained from sow colostrum or soy bean also enhanced the transmission of both BSA and FITC-D while the inactive inhibitors, given as trypsin-inhibitor complexes, had no effect. On the other hand, addition of a proteinase, porcine trypsin, significantly decreased the transmission of FITC-D. These findings indicate that the intestinal transmission of macromolecules in the preclosure piglet is governed by the amount of protein available in the intestine. Therefore, feeding colostrum with a high protein content and proteinase inhibitors is likely to favour efficient intestinal transmission, although other colostrum factors may also be of importance.

The effects of soybean trypsin inhibitors on the pancreas of animals and man: a review.

Human trypsin is more resistant to inhibition than is the trypsin of other mammalian species. The effect on human trypsin of soybean trypsin inhibition in soy protein does not appear to be a potential hazard to man. Therefore, the elimination of STI does not seem to be necessary for humans. In animal diets, however, pancreatic toxicity must be considered whenever soybean protein is utilized. Soybeans should be treated to increase their nutritional benefits and decrease any animal health risks (27-29). This will insure healthy control subjects in laboratory situations and avoid misinterpretation of pathologic data. The treatment suggested is heat (2,18,25,30-32) since heat will destroy most of the soybean trypsin inhibitors. Additional supplementation is required following heat treatment for amino acids (33,34) such as methionine, valine, and threonine; for choline (2,14,35); and for the minerals zinc (36) and calcium (11,34). Excessive heat must be avoided since it will decrease the nutritional value of soybean protein and increase lysinoalanine, a nephrotoxic substance (12). Finally, the use of STI as a promotor in the study of potential pancreatic carcinogens may prove beneficial for cancer research (24,25) and might be considered in the future.

[Effect of trypsin inhibitor of a peptide-protein nature on kallikreins from human and rabbit blood stream]. / Deistzie Ingibitoroz Tripsina Peptidno-Belkozoi Prirody Na Kallikreiny Cyzorotiki Krozi Chelozeka I Krolika

The effect of three natural trypsin inhibitors--polyvalent Kunitz inhibitor (BPTI), the inhibitor from cow colostrum (CTI) and the inhibitor from soybean (SBTI)--on esterase and kininogenase action of partially purified kallikrein preparations from human and rabbit blood serum is studied. The effect of each inhibitor was estimated from Ki values. The latters show that BPTI, SBTI and CTI are strong inhibitors of both kallikreins. Ki values, as estimated from the hydrolysis rate of N-bensoyl-L-arginine ethyl ester, were found to be for human blood serum kallikrein and BPTI, SBTI and CTI 1,1-10(-9), 4,7-10(-9) and 3,6-10(-8) M respectively and for rabbit kallikrein--1,7-10(-9), 2,3-10(-8) and 2,3-10(-8) M. In the case of kallikrein catalysing more specific kininogenase reaction Ki value for complex of human serum kallikrein with BPTI was 4,8-10(-10) M, for SBTI--1,1-10(-10) M and for CTI--3,6-10(-8) M; for rabbit kallikrein--1,7-10(-9) M, 1,1-10(-9) and 2,3-10(-8) M respectively. The data obtained suggest the high sensitivity of human and rabbit serum kallikreins to the trypsin inhibitor of peptide-protein nature and a close similarity in composition of the active site for both serum kallikreins and trypsin, two spices different kininogenases--from human and rabbit serum had also similarity in molecule conformation and composition active site.