Other novel agents: Rationale and current status as chemopreventive agents

A Review of Bioactive Compound Effects from Primary Legume Protein Sources in Human and Animal Health

The global demand for sustainable and nutritious food sources has catalyzed interest in legumes, known for their rich repertoire of health-promoting compounds. This review delves into the diverse array of bioactive peptides, protein subunits, isoflavones, antinutritional factors, and saponins found in the primary legume protein sources-soybeans, peas, chickpeas, and mung beans. The current state of research on these compounds is critically evaluated, with an emphasis on the potential health benefits, ranging from antioxidant and anticancer properties to the management of chronic diseases such as diabetes and hypertension. The extensively studied soybean is highlighted and the relatively unexplored potential of other legumes is also included, pointing to a significant, underutilized resource for developing health-enhancing foods. The review advocates for future interdisciplinary research to further unravel the mechanisms of action of these bioactive compounds and to explore their synergistic effects. The ultimate goal is to leverage the full spectrum of benefits offered by legumes, not only to advance human health but also to contribute to the sustainability of food systems. By providing a comprehensive overview of the nutraceutical potential of legumes, this manuscript sets a foundation for future investigations aimed at optimizing the use of legumes in the global pursuit of health and nutritional security.

Proteases, protease inhibitors and radiation carcinogenesis

PURPOSE

The purpose of the studies described in this mini review article was to identify nontoxic compounds that could prevent or suppress the radiation induced malignant transformation of cells and be useful as human cancer preventive agents.

CONCLUSIONS

(1) Many different types of potential anticarcinogenic substances were evaluated initially for their abilities to prevent or suppress radiation induced malignant transformation in vitro, and certain anticarcinogenic protease inhibitors (APIs) were observed to be the most powerful anticarcinogenic agents at suppressing this surrogate endpoint biomarker of radiation carcinogenesis. (2) Within the category of APIs, those that inhibited the activity of chymotrypsin were effective at far lower molar concentrations than other APIs. The soybean-derived protease inhibitor known as the Bowman-Birk inhibitor (BBI) is a particularly powerful chymotrypsin inhibitor that is able to prevent radiation induced transformation in vitro (at concentrations down to nanomolar levels) as well as radiation induced carcinogenesis in vivo without toxicity. (3) There were many other unusual characteristics of APIs that led to the selection of one of these APIs, BBI, as the most appropriate compound for us to develop as a human cancer preventive agent. As one example, the APIs have an irreversible effect on carcinogenesis, while the effects are reversible for most anticarcinogenic agents when they are removed from carcinogenesis assay systems. (4) Numerous studies were performed in attempts to determine the potential mechanisms by which the APIs could prevent or suppress radiation induced carcinogenesis in in vitro and in vivo systems, and the results of these studies are described in this review article. The APIs and the proteases which interact with them appear to play important roles in radiation carcinogenesis. (5) Preparations for human trials using BBI began decades ago. The cost of preparing purified BBI was far too high to consider performing human trials with this agent, so BBI Concentrate (BBIC), a soybean extract enriched in BBI, was developed for the specific purpose of performing human trials with BBI. BBIC achieved Investigational New Drug (IND) Status with the Food and Drug Administration in April,1992, and human BBIC trials began at that time. (6) Several human trials were performed using BBIC and they indicated many potentially beneficial health effects produced by BBIC administration to people in various forms (e.g. tablets). 7) It is hypothesized that BBI takes the place of α-1-antichymotrypsin, an important regulatory compound in the human body, and helps to maintain homeostasis.

Effect of different process parameters on the quality of soymilk and tofu from sprouted soybean

The effect of grinding cum blanching (GCB) of sprouted soybean at different temperatures on milk and tofu quality was studied. Three temperatures (121 °C-T1,100 °C-T2 and 80 °C-T3) for GCB were used to produce soymilk and tofu from sprouted soybean which were analysed for the yield, nutritional, anti-nutritional profile, colour attributes, particle size, organoleptic quality and texture profile. Unsprouted Soybeans with GCB at 121 °C served as control (C). There was significant difference (P < 0.5) in trypsin inhibitor content in milk and ranged from 4.1 mg/g in T3 to 1.4 mg/g in T1. Optimal reduction in TI of 75-80 % was achieved in T2. There was significant difference (P < 0.5) in protein extractability and ranged from 84.4 % in C to 93.9 % in T2. Hardness (N) of tofu was around 11.22 in C and reduced to 8.9, 8.6 and 4.4 in T1, T2 and T3 respectively. L values of soymilk ranged from 83.4 in C to 85.8 in T3; in tofu from 83.1(T3) to 87.2 (C) and decreased with the increase in heating temperature and time. Particle size d [3, 2] and volume d [4, 3] between treatments varied significantly (P < 0.0001 and P < 0.0038). Overall acceptability scores on 9 point hedonic scale for all treatments for milk and tofu were above 5. The texture scores of tofu for T3 were very low due to its soft structure. From the above investigations 100 °C was the optimal temperature for GCB of sprouted soybean for the production of good quality soymilk and tofu.

The biochemical and functional food properties of the bowman-birk inhibitor

The Bowman-Birk inhibitor (BBI) is a small water-soluble protein present in soybean and almost all monocotyledonous and dicotyledonous seeds. The molecular size of BBI ranges from 1,513 Da to about 20,000 Da. BBI is to seeds what alpha(1)-antitrypsin is to humans. Soy-based food products rich in BBI include soybean grits, soymilk, oilcake, soybean isolate, and soybean protein concentrate. BBI is stable within the pH range encountered in most foods, can withstand boiling water temperature for 10 min, resistant to the pH range and proteolytic enzymes of the gastrointestinal tract, bioavailable, and not allergenic. BBI reduces the proteolytic activities of trypsin, chymotrypsin, elastase, cathepsin G, and chymase, serine protease-dependent matrix metalloproteinases, urokinase protein activator, mitogen activated protein kinase, and PI3 kinase, and upregulates connexin 43 (Cx43) expression. Several studies have demonstrated the efficacy of BBI against tumor cells in vitro, animal models, and human phase IIa clinical trials. FDA considers BBI as a drug. In 1999, FDA allowed a health claim on food labels stating that a daily diet containing 25 grams of soy protein, also low in saturated fat and cholesterol, may reduce the risk of heart disease [corrected] This review highlights the biochemical and functional food properties of the Bowman-Birk inhibitor.

Phytoestrogens and prostate cancer risk

BACKGROUND

Phytoestrogens are natural plant substances. The four main classes are isoflavones, flavonoids, coumestans, and lignans. Phytoestrogens have anti-carcinogenic potential. For evaluation of the effect of phytoestrogens on prostate cancer risk, we reviewed analytical epidemiological data.

METHODS

Up to now, there are few studies that have assessed the direct relation between the individual dietary intake of soy products and other nutrients with phytoestrogens and the risk of prostate cancer. We decided to review analytical epidemiological studies providing data on (a) dietary soy intake or flavonoids intake, (b) urinary excretion of isoflavones or lignans, or (c) blood measurements of isoflavones or lignans. Soy is used as a marker for isoflavone intake.

RESULTS

Overall, the results of these studies do not show protective effects. Only four of these studies are prospective, and none of them found statistically significant prostate cancer reductions. Two prospective studies measured flavonoid intake and one reported a preventive effect on prostate cancer for the assumption of myricetin. One study assessed enterolactone concentrations in three different countries and showed no reduction in prostate cancer occurrence.

CONCLUSION

Few studies showed protective effect between phytoestrogen intake and prostate cancer risk.

Apoptotic regulators in prostatic intraepithelial neoplasia (PIN): value in prostate cancer detection and prevention

Early diagnosis of prostate cancer holds tremendous promise for the effective therapy and impact on survival of prostate cancer patients. High-grade prostatic intraepithelial neoplasia (HGPIN) is generally accepted as a lesion indicative of a late pathological event in the premalignant changes leading to full development of prostate cancer. This review seeks to identify specific molecular events that may be linked directly to the molecular transition from benign prostate epithelial cells to prostate carcinoma. HGPIN is pathologically detected in a limited group of men undergoing prostate cancer screening for an elevated serum prostate-specific antigen (PSA) or abnormal digital rectal examination (DRE). Loss of apoptotic control provides a molecular basis for the contribution of specific defective steps in the pathway towards development and progression of prostate cancer. Comparative dissection of the apoptosis status and expression profile of key apoptotic regulators among foci of highly proliferative benign prostatic epithelium, PIN and prostate adenocarcinoma from adjacent areas of the same gland revealed a novel insight into the dysfunctional apoptosis events contributing to prostate carcinogenesis. The sequential and notable loss of the three critical signaling components of the apoptotic action of transforming growth factor-beta (TGF-beta), in the prostate, that is, the transmembrane receptor II (TbetaRII), the key cell cycle inhibitor p27(Kip1), as well as the protagonist downstream effector of the TGF-beta signaling mechanism, Smad4, points to their potential value to 'faithfully' characterize HGPIN, as a premalignant prostate lesion. Recent evidence on the molecular changes in apoptosis regulators contributing to HGPIN and their role as molecular markers of disease onset, as well as candidates for therapeutic targeting/chemoprevention of prostate cancer in its early stages will be discussed.

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.

The molecular basis of skeletal metastases

Metastasis is the culmination of numerous highly regulated sequences of steps that results in the proliferation and migration of cells from the primary site to a distant location. The biologic consequence of skeletal metastasis is focal bone sclerosis or osteolysis that leads to pain, pathologic fracture, and biochemical derangement. The difficulty in determining a point of control for clinical application has been because of the numerous systems, substrates, ligands, receptors, factors, and pathways that exist. These may be grouped into functional mechanisms identifiable by their relevance to the metastatic process. These include cell-cell or cell-matrix adhesion, invasion and migration, interactions with endothelial cells, growth factor regulation, proteolysis, and stimulation of differentiated osteoblast and osteoclast function. The challenge for cancer therapy will be to identify means to prevent metastasis or reduce its effect once it occurred. This review examines recent advances in the study of molecular processes of metastasis, which have identified potential sites and substrates for targeting with novel therapies and agents.

Do soy isoflavones lower cholesterol, inhibit atherosclerosis, and play a role in cancer prevention?

This article is designed to help nursing professionals advise patients about the role of soy in the prevention and treatment of heart disease, breast cancer, and prostate cancer. Soy protein lowers total cholesterol, low-density lipoprotein cholesterol, and triglycerides in humans and inhibits atherosclerosis in animals. In cell culture studies and animal research, the soy isoflavone genistein offers protection from breast cancer and prostate cancer because it prevents cancer initiation, slows promotion, and impedes cancer progression. This article synthesizes the current research concerning soy phytoestrogens and the prevention and treatment of heart disease, breast cancer, and prostate cancer. Nursing professionals may use this information when counseling patients.

Highlights of contemporary issues in the medical management of prostate cancer

This paper highlights contemporary issues in the medical management of prostate cancer. Controversies surrounding adjuvant and neo-adjuvant hormonal therapy in localized prostate cancer are reviewed, as well as the use of chemohormonal therapy in high risk localized disease. The latent period of asymptomatic biochemical progression prior to clinical progression is an opportunity to evaluate new non-toxic therapies. In patients with advanced metastatic disease hormonal therapy and new alternatives are discussed. Chemotherapy in hormone refractory prostate cancer (HRPC) is extensively covered as well as the emerging role of molecular-targeted therapies.