Natural and synthetic agents targeting inflammation and angiogenesis for chemoprevention of prostate cancer.

Prostate cancer is the most common cancer in men and one of the leading causes of cancer-related deaths in Western countries. The extraordinary biological heterogeneity, the increasing incidence of this disease, and the presence of putative premalignant conditions make prostate cancer a crucial pathology to study and test pharmacological or nutritional chemopreventive strategies. It has been demonstrated that the incidence of prostate cancer is lower in Asian people, and that it increases in Asian men living in Western countries; these data point to a pivotal role of diet in the onset of prostate cancer.

Hyperforin down-regulates effector function of activated T lymphocytes and shows efficacy against Th1-triggered CNS inflammatory-demyelinating disease.

Hyperforin (Hyp) is an active compound contained in the extract of Hypericum perforatum, well known for its antidepressant activity. However, Hyp has been found to possess several other biological properties, including inhibitory effects on tumor invasion, angiogenesis, and inflammation. In this paper, we show that treatment with Hyp inhibited IFN-gamma production, with down-regulation of T-box (T-bet; marker of Th1 gene expression) and up-regulation of GATA-3 (marker gene of Th2) on IL-2/PHA-activated T cells.

Matrix proteases, green tea, and St. John's wort: biomedical research catches up with folk medicine.

Background: Some proteases involved in extracellular matrix degradation are instrumental not only in overcoming tissue barriers to allow normal extravasation of hematic cells, but also in facilitating pathological processes such as inflammation, angiogenesis and tumor invasion. The possibility of blocking these enzymes has led to the development of synthetic inhibitors, though clinical trials have been disappointing owing to considerable side effects. However, long before enzymes were first isolated, these same pathologies were being treated in plant-based folk remedies, and today science is screening them for their reputed beneficial effects.

Hyperforin blocks neutrophil activation of matrix metalloproteinase-9, motility and recruitment, and restrains inflammation-triggered angiogenesis and lung fibrosis.

Hyperforin (Hyp), a polyphenol-derivative of St. John's wort (Hypericum perforatum), has emerged as key player not only in the antidepressant activity of the plant but also as an inhibitor of bacteria lymphocyte and tumor cell proliferation, and matrix proteinases. We tested whether as well as inhibiting leukocyte elastase (LE) activity, Hyp might be effective in containing both polymorphonuclear neutrophil (PMN) leukocyte recruitment and unfavorable eventual tissue responses.

Inhibition of leukocyte elastase, polymorphonuclear chemoinvasion, and inflammation-triggered pulmonary fibrosis by a 4-alkyliden-beta-lactam with a galloyl moiety.

beta-Lactams, a well known class of antibiotics, have been investigated as inhibitors of the disruptive protease released by inflammatory cells, leukocyte elastase (LE). We have synthesized a new beta-lactam with an N-linked galloyl moiety, the latter identified as strategic in conferring anti-LE properties to some flavonols. This N-galloyl-derivative beta-lactam inhibits the LE activity with a K(i) of 0.

Prostate carcinoma and green tea: PSA-triggered basement membrane degradation and MMP-2 activation are inhibited by (-)epigallocatechin-3-gallate.

Prostate-specific antigen (PSA) is a serine-protease that, in addition to cleaving semenogelins in the seminal coagulum, is able to cleave extracellular matrix glycoproteins, thereby affecting cell migration and metastasis. We here report some new activities of PSA that deserve careful consideration in the cancer context: degradation of gelatin, degradation of type IV collagen in reconstituted basement membrane (Matrigel) and activation of progelatinase A (MMP-2), but not pro-MMP-9, in a cell-free system. Since consumption of green tea has been reported to lower the risk of prostate cancer, we investigated the effects of the major flavanol of green tea, (-)epigallocatechin-3-gallate (EGCG), on expression and activity of PSA by prostate carcinoma cells.

Prostate carcinoma and green tea: (-)epigallocatechin-3-gallate inhibits inflammation-triggered MMP-2 activation and invasion in murine TRAMP model.

Green tea infusion has been shown to inhibit metastatic spreading of the transgenic adenocarcinoma of mouse prostate (TRAMP). Investigation on the molecular mechanisms triggered by the main green tea flavonoid, (-)epigallocatechin-3-gallate (EGCG), shows that EGCG restrains TRAMP-C1 cell proliferation in a dose-dependent manner, at concentrations (IC(50) < 0.2 microM) equivalent to those measured in the plasma of moderate green-tea drinkers.

Hyperforin inhibits cancer invasion and metastasis.

Hyperforin (Hyp), the major lipophilic constituent of St. John's wort, was assayed as a stable dicyclohexylammonium salt (Hyp-DCHA) for cytotoxicity and inhibition of matrix proteinases, tumor invasion, and metastasis. Hyp-DCHA triggered apoptosis-associated cytotoxic effect in both murine (C-26, B16-LU8, and TRAMP-C1) and human (HT-1080 and SK-N-BE) tumor cells; its effect varied, with B16-LU8, HT-1080, and C-26 the most sensitive (IC50 = 5 to 8 micromol/L).

Potent inhibitors of anthrax lethal factor from green tea.

The anthrax lethal factor (LF) has a major role in the development of anthrax. LF is delivered by the protective antigen (PA) inside the cell, where it exerts its metalloprotease activity on the N-terminus of MAPK-kinases. PA+LF are cytotoxic to macrophages in culture and kill the Fischer 344 rat when injected intravenously.

Functional in vivo gene transfer into the myofibers of adult skeletal muscle.

The postmitotic nature and longevity of skeletal muscle fibers permit stable expression of any transfected gene. Direct in vivo injection of plasmid DNA, in both adult and regenerating muscles, is a safe, inexpensive, and easy approach. Here we present an optimized electroporation protocol based on the use of spatula electrodes to transfer cDNA in vivo into the adult myofibers of an anatomically defined muscle, which could be functionally characterized.

Proteinase-3 directly activates MMP-2 and degrades gelatin and Matrigel; differential inhibition by (-)epigallocatechin-3-gallate.

Proteinase-3 (PR-3), a serine-proteinase mainly expressed by polymorphonuclear leukocytes (PMNs), can degrade a variety of extracellular matrix proteins and may contribute to a number of inflammation-triggered diseases. Here, we show that in addition to Matrigel(TM) components, PR-3 is also able to degrade denatured collagen and directly activate secreted but not membrane-bound pro-MMP-2, a matrix metallo-proteinase instrumental to cellular invasion. In contrast, following addition of purified PR-3 or PMNs to HT1080 tumor cells, dose-dependent inhibition of in vitro Matrigel(TM) invasion is registered.

Neutrophil restraint by green tea: inhibition of inflammation, associated angiogenesis, and pulmonary fibrosis.

Neutrophils play an essential role in host defense and inflammation, but the latter may trigger and sustain the pathogenesis of a range of acute and chronic diseases. Green tea has been claimed to exert anti-inflammatory properties through unknown molecular mechanisms. We have previously shown that the most abundant catechin of green tea, (-)epigallocatechin-3-gallate (EGCG), strongly inhibits neutrophil elastase.

(-)Epigallocatechin-3-gallate directly inhibits MT1-MMP activity, leading to accumulation of nonactivated MMP-2 at the cell surface.

Consumption of green tea has been associated with prevention of cancer development, metastasis, and angiogenesis. Given the crucial role of the matrix metallo-proteinase-2 (MMP-2) on the degradation of the extracellular matrix instrumental to invasion, we examined the effect of the main flavanol present, (-)epigallocatechin-3-gallate (EGCG), on membrane-type 1 MMP (MT1-MMP), the receptor/activator of MMP-2. In-solution fluorimetric assay with activated MT1-MMP and gelatin-zymography with MT1-MMP catalytic domain alone and pro-MMP-2 activation by the same domain revealed dose-dependent inhibition of MT1-MMP at EGCG concentrations slightly lower than that reported to inhibit MMP-2 and MMP-9.

Inhibition of matrix-proteases by polyphenols: chemical insights for anti-inflammatory and anti-invasion drug design.

Flavanols--a class of plant polyphenols abundant in tea leaves and grape seeds and skins--have been found to inhibit some matrix-proteases instrumental in inflammation and cancer invasion, such as leukocyte elastase (LE) and gelatinases. In order to establish the relationship between chemical structure and activity, 27 different flavonoids (antocyanidins, dihydrochalcones, dihydroflavonols, flavanolignans, flavanols, flavones, flavonols and isoflavones) and other compounds with anti-oxidant properties were evaluated for their potential in blocking LE and gelatinase activities. LE activity was measured using a chromogenic substrate: from comparison of the different levels of inhibition, it was deduced that a crucial role in inhibition might be played by a galloyl moiety or hydroxyl group at C3, three hydroxyl groups at B ring, one hydroxyl group at C4', and a 2,3-double bond.