Effect of Enzymatic Digestion of Protein Derivatives Obtained from Mucuna pruriens L. on Production of Proinflammatory Mediators by BALB/c Mouse Macrophages.

Inflammation is considered to be a major risk factor for the pathogenesis of chronic non-communicable diseases. Macrophages are important immune cells, which regulate inflammation and host defense by secretion of proinflammatory mediators. Obtaining biopeptides by enzymatic hydrolysis adds value to proteins of vegetative origin, such as Mucuna pruriens L. The present study evaluated the effect of enzymatic digestion of protein derivatives obtained from M. pruriens L. on the production of proinflammatory mediators by BALB/c mouse macrophages. Five different molecular weight peptide fractions were obtained (F > 10, 5-10, 3-5, 1-3, and < 1 kDa, respectively). At 300 µg/mL, F5-10 kDa inhibited 50.26 and 61.00% NO and H2O2 production, respectively. Moreover, F5-10 kDa reduced the IL-6 and TNFα levels to 60.25 and 69.54%, respectively. After enzymatic digestive simulation, F5-10 kDa decreased the inflammatory mediators.

Enhanced TGFalpha-EGFR expression and P53 gene alterations contributes to gastric tumors aggressiveness.

We determined whether alterations in the expression of p53, p16(INK4) and p21(WAF1/CIP1) influence the invasiveness of a subset of gastric adenocarcinomas co-expressing TGFalpha and EGFR. Immunopositivity for TGFalpha-EGFR (26%) was observed in both early and advanced adenocarcinomas, and 88% of these showed immunoreactivity for p53. SSCP analysis revealed that in 81% of these tumors the p53 gene was mutated in exons 5-8. The intensity of p53 immunoreactivity was significantly higher (P < 0.013) in deeply invasive tumors. p16(INK4) and p21(WAF1/CIP1) immunoreactivity was detected in 93 and 76% of the samples co-expressing TGFalpha-EGFR but the levels were not correlated with those of p53 and other clinico-pathological parameters. We conclude that gastric adenocarcinomas potentially dependent upon the TGFalpha-EGFR autocrine loop for growing exhibit increased aggressiveness in the presence of aberrant p53.

Epidermal growth factor and transforming growth factor alpha mRNA expression in human breast cancer biopsies; analysis in relation to estradiol, progesterone and EGF receptor content.

Among the peptide growth factors active in breast glandular cell proliferation epidermal growth factor (EGF) and transforming growth factor alpha (TGF alpha) are thought to play a major role in tumour development. They operate through binding to and activation of a common membrane receptor, defined as EGF-R. Their production is modulated by hormones and local growth factors. After it was shown by previous investigation in this laboratory that EGF-R could be detected in 90% of the tumours, but was masked by endogenous ligand in 36% of them, the question was raised as to the level of the ligand's expression in tumour tissue biopsies. Therefore, we investigated the expression of EGF and TGF alpha mRNA in 146 breast cancer biopsies by slot blot analysis using specific 32P-labelled probes. The data were correlated with sex steroids and EGF receptor content. Our results showed that EGF and TGF alpha coexisted in all tumour samples, and that their level of mRNA expression was similar in half of the tumours. Northern blot and polymerase chain reaction (PCR) analysis validated these findings. A significant direct correlation was found between the level of TGF alpha/EGF mRNA expression and the ER/progesterone receptor (PGR) content. TGF alpha and EGF mRNA levels were significantly higher in ER+ (P = 0.0015 and P = 0.0001, respectively) and in PGR+ tumours (P < 0.005 and P = 0.0001) than in their negative counterparts. Moreover, TGF alpha mRNA expression negatively correlated with the number of EGF-R binding sites measured by the standard method (P = 0.02), and it was significantly related to the number of sites occupied by endogenous ligand. In conclusion, it was shown that TGF alpha and EGF mRNA were coexpressed in all the tumour biopsies tested and that their level was higher in the hormone receptor positive than in negative samples. The correlation between the presence of ER/PGR sites, high level of TGF alpha/EGF mRNA and EGF-R occupancy by endogenous ligand is in favour of ER mediated control of TGF alpha and EGF production.

Correlation of TGF-beta 1 expression with medroxyprogesterone acetate responsiveness in mouse mammary adenocarcinomas.

We investigated the expression of transforming growth factors beta 1 and alpha (TGF-beta 1, TGF-alpha) in hormone-responsive (MPA-R) and unresponsive (MPA-U) tumor lines obtained from medroxyprogesterone acetate (MPA)-induced mammary adenocarcinomas in BALB/c mice. The tumors were transplanted into MPA-treated and untreated mice. TGF-beta 1 gene expression was observed in the MPA-R lines growing in untreated animals, but not in MPA-treated mice. TGF-beta 1 mRNA was not detected in the MPA-U tumor lines growing in either MPA-treated or untreated animals. In MPA-R lines the levels of TGF-beta 1 expression were inversely correlated to growth rate. High-affinity TGF-beta 1 receptors were present in the MPA-R tumors. These results suggest that one of the mechanisms by which MPA exerts its proliferative effect on MPA-R tumor lines is inhibition of the expression of TGF-beta 1. Thus, the lack of expression of TGF-beta 1 in MPA-U tumors may be related to the acquisition of autonomous growth.

Effects of androgens on proliferation and progesterone receptor levels in T47D human breast cancer cells.

The effects of estradiol (E2), dihydrotestosterone (DHT) and dehydro-3-epiandrosterone (DHEA) on proliferation and progesterone receptor induction were studied in a breast cancer cell line (T47D) expressing estrogen, androgen, and progesterone receptors. A significant enhancement of growth and progesterone receptor expression was observed after treatment with E2 and DHEA, which was antagonized by the antiestrogen tamoxifen and not altered by the antiandrogen flutamide, supporting the involvement of estrogen receptors. When cells were treated with either E2 or DHEA, transforming growth factor-alpha mRNA was induced. DHT treatment did not alter growth but was effective in stimulating androgen receptors and down-regulating progesterone receptors.

Alpha-transforming growth factorlike activities and bifunctional regulators of cell growth in human malignant neoplasms.

Multiple transforming growth factors (TGFs) capable of conferring the neoplastic phenotype on NRK-49F cells without the addition of any other exogenous growth factor in the soft agar assay, were purified from two human solid malignant neoplasms: a squamous lung carcinoma and a pectoral rhabdomyosarcoma. In both tumors, low-molecular-weight transforming activities (4000-6000) that were not potentiated by epidermal growth factor (EGF), competed for binding to the EGF receptor, possessed mitogenic activity on NRK fibroblasts arrested in serum-deprived medium, and did not show inhibitory effects on DNA synthesis induced by EGF and insulin in NRK cells. Other TGFs with molecular weights 9000 to 48,000, were also found in the malignant tissues examined; these TGFs, were not potentiated by EGF, did not compete for binding to the EGF receptor, were not mitogenic for NRK cells, and acted as potent inhibitors of DNA synthesis induced by EGF and insulin in NRK cells. These results demonstrate that growth-promoting activities, and modulating agents that can act as either enhancers or inhibitors of cell proliferation, are present in neoplastic tissues of different embryologic origin and histologic type.