Correlation of preoperative citology/histology in radiologically detected lesions and histologic findings at excision

1552

Background: The major techniques used to diagnose breast abnormality has been for many years fine-needle aspiration (FNA) cytology and core needle biopsy (CNB) and more recently vacuum-assisted core biopsy (VACB). These techniques are accurate and allow definitive therapeutic surgery. The aim of our study was to detemine whether cytology/histologic findings mach histologic findings at excision. Methods: In our Institution, between January 2004 and June 2006, 43,138 mammographic exams were performed. 1,012 patients had patological lesions at mammography: 617 FNA cytology ( C due to European guidelines for breast cancer screening assessment) and 395 CNB/VACB (B) were performed. Patients with respectively suspicious and malignant FNA cytology (C4 and C5) and respectively uncertain malignant potential, suspicious and malignant histology (B3, B4 and B5) underwent to surgery. Results: The number of cancer identified by FNA cytology was 158 and the number of cancer identified by CNB/VACB was 253. The correlation of preoparative citology/histology with definitive histology had showed: false negative rate respectively 0.79% for histology (B) and 3.16% for cytology (C). False positive rate was respectively 0.4% for B and 0.63 for C. Complete sensitivity was 98.2% for B and 89.87% for C. Absolute sensitivity was 90.51% for B and 76.58% for C. Conclusions: Our data demostrated very high performance of diagnostic preoperative procedures due to multidisciplinary approach between the radiologists, the clinicians and the pathologists.

No significant financial relationships to disclose.

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. The results show that, without affecting in vitro human PMN viability and chemokine-receptor expression, Hyp (as stable dicyclohexylammonium salt) was able to inhibit in a dose-dependent manner their chemotaxis and chemoinvasion (IC50=1 microM for both); this effect was associated with a reduced expression of the adhesion molecule CD11b by formyl-Met-Leu-Phe-stimulated neutrophils and block of LE-triggered activation of the gelatinase matrix metalloproteinase-9. PMN-triggered angiogenesis is also blocked by both local injection and daily i.p. administration of the Hyp salt in an interleukin-8-induced murine model. Furthermore, i.p. treatment with Hyp reduces acute PMN recruitment and enhances resolution in a pulmonary bleomycin-induced inflammation model, significantly reducing consequent fibrosis. These results indicate that Hyp is a powerful anti-inflammatory compound with therapeutic potential, and they elucidate mechanistic keys.

Implementation of 18F-FDG PET/CT in the management of colon cancer

13526

Background: we began using PET in 1994 and since the beginning of 2000 we started with a PET/CT system. Aim of our study was to evaluate if PET/CT is a decision making tool in patients with a history of colon tumors. Methods: we performed PET/CT in 26 patients, 14 males and 12 females (mean age 60.9, range 42–75 years) already treated for a colon cancer. Each patient was submitted to two PET/CT scans in a period of 5–11 months. PET/CT was performed using 18F-FDG as radiopharmaceutical. In all patients other examinations were perfomed, such as liver ecography, pelvis MRI and CT scan. Results: in the first PET/CT imaging, 11/26 patients presented with normal tumor markers but suspected relapse on the basis of CI, 7/26 had increased markers but negative CI, the other 8 patients had both CI and tumor markers meaningful for recurrence. 7/26 PET/CT were normal: 5 cases with negative tumor markers but positive CI and 2 patients with increased CEA levels. Among the 19/26 positive PET/CT scans, 7 patients had normal marker levels. All positive PET/CT patients were treated and, at the second examination, progressive disease was evident in 11 out of 19. For the 7 previous negative PET/CT, the second findings showed tumor recurrence in 2 patients, but PET/CT became negative in 5 previously positive cases, submitted to surgery and/or chemotherapy. This method detected relapse in 73% of the patients and, during the follow up, it was sensitive to identify progressive disease or to prove treatment’colon cancer, based on tumoral marker assays and CI, is poorly sensitive to detect relapse. Our PET/CT data show that 37% of cases with normal marker levels have a recurrent disease. The overall results of our preliminary data lead to further considerations: 1) PET/CT gives a precise localization of lung or nodal metastases and local relapse; 2) the repeated PET/CT scan is reliable also to evaluate the effect of therapies; 3) this imaging modality may be crucial to detect relapse, but more data are needed to assess the proper time to perform PET/CT in the follow up to have a real gain in life expectancy.

No significant financial relationships to disclose.

Diagnosis of recurrent breast cancer: 18F-FDG PET/TAC as first choice

10681

Background: we began using PET diagnosis in 1994 and since the beginning of 2000 we started with a PET/CT system. Aim of our study was to evaluate if this new imaging modality may be the first step in the detection of recurrence in patients with a history of breast tumors. Methods: we reviewed retrospectively 22 patients (mean age 60, range 46–76 years) already treated for a breast cancer. A total of 32 PET/CT scans were performed (repeated in 10 patients). All patients were submitted to other examinations, such as bone scintigraphy and liver ecography, but also mammography and CT scan. Results: 14/32 PET/CT were negative for recurrence in 10 patients (4 scans as a second one). In a mean follow up of 10 months, 1 case is not yet clear: in presence of relevant increase of Ca15.3 (up to 176 ng/ml) the first scan was negative and the second one evidentiated a pattern of lung inflammation. Among the other 13/14 negative scans, 3 patients presented ambiguous/positive bone scintigraphy for metastases, not assessed at the final diagnosis. 18/32 PET/CT scans were positive for local recurrence or distant metastases. Among these positive cases, a patient with normal bone scintigraphy presented a mild uptake of FDG in the right omerus. The second scan (5 months later) showed focal increased uptake of FDG in the same bone site, not evident in the CT images, and many small lung nodules, 1–2 mm size. In 3 patients PET localized muliple bone lesions, in 2 CT was completely normal. Finally, 1 out of the 18 positive results was false positive: a patients with a single lung nodule (1.5 cm) was submitted to surgery and the final diagnosis was benign lesion. PET/CT was crucial for the patient’s management in 19 out of 22 patients. Conclusions: recurrent breast cancer is generally characterized by multiple sites of metastases and few cases take advantage of surgical resection. In our group of 22 patients just 2 out of them received surgery (for local relapse and lung metastases). Therefore, in most cases a whole body examination, like PET/CT may be more useful respect to other modalities to assess how spread is the recurrence. Further data are needed but, in our preliminary experience, PET/CT seems to be the first choice to evaluate patients with previous breast cancer.

No significant financial relationships to disclose.

4-Alkyliden-β-lactams conjugated to polyphenols: Synthesis and inhibitory activity

A series of compounds combining the beta-lactam and polyphenol scaffold have been prepared and evaluated for inhibition of human leukocyte elastase and matrix metallo-proteases MMP-2 and MMP-9. The design of these compounds has been based on the 'overlapping-type' strategy where two pharmacophores are linked in a single molecule. The most powerful compound against elastase was an N-galloyl-4-alkyliden beta-lactam, [3-[1-(tert-butyl-dimethyl-silanyloxy)-ethyl]-4-oxo-1-(3,4,5-tris-benzyloxy-benzoyl)-azetidin-2-ylidene]-acetic acid ethylester, with an IC50 of 0.5 microM; while the most powerful against MMP-2 was a 4-alkyliden beta-lactam arylated on the C-3 hydroxy side chain (3,5-bis-benzyloxy-4-hydroxy-benzoic acid 1-(2-benzyloxycarbonylmethylene-4-oxo-azetidin-3-yl)-ethyl ester) with an IC50 of 4 microM. Of the total 35 compounds tested, high levels of inhibition of elastase and of MMPs were separately exerted by distinct molecules.

Inhibition of Leukocyte Elastase, Polymorphonuclear Chemoinvasion, and Inflammation-Triggered Pulmonary Fibrosis by a 4-Alkyliden-β-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 0.7 microM, whereas it exerts weak activity against cathepsin G and protease-3 (IC(50) > 100 microM), and matrix metalloproteinase (MMP)-2 and MMP-9. Without affecting chemotactic response and viability of polymorphonuclear (PMN) leukocytes, the compound efficiently restrains their chemoinvasion (IC(50) of 1-2 microM) blocking the LE-triggered activation of pro-MMP-9, instrumental to extravasation. Daily i.p. injection of compound enhances resolution in a pulmonary inflammation model, significantly reducing consequent fibrosis. These results indicate that the new beta-lactam is a potent anti-inflammatory compound with therapeutic potential.

A phase I-II study of weekly oxaliplatin, 5-fluorouracil continuous infusion and preoperative radiotherapy in locally advanced rectal cancer

BACKGROUND

Oxaliplatin (OXA) significantly enhanced the antitumour activity of 5-fluorouracil (FUra) in patients with advanced colorectal cancer and displayed radiosensitising properties in preclinical studies. This study was thus performed to test the feasibility, identify the recommended doses (RDs) and explore preliminarily the clinical activity of weekly OXA and infused FUra combined with preoperative pelvic radiotherapy.

PATIENTS AND METHODS

Forty-six patients with recurrent or locally advanced (cT3-4 and/or N+) adenocarcinomas of the mid-low rectum were treated with escalating doses of OXA (25, 35, 45, 60 mg/m2, weekly for 6 weeks) and FUra (200-225 mg/m2/day, 6-week infusion) concurrent to preoperative pelvic radiotherapy (50.4 Gy/28 fractions). The RDs for the phase II part of the study were immediately below the level resulting in dose-limiting toxicities in more than one third of the patients, or corresponded to the last planned dose level.

RESULTS

In the escalation phase, dose-limiting toxicities only occurred in one patient at the fourth level and one of six patients treated at the last planned dose level (grade III diarrhoea). OXA 60 mg/m2 and FUra 225 mg/m2/day are therefore the RDs for the regimen. Among 25 patients globally treated at these doses (phase II part), the incidence of grade III diarrhoea was 16% with no grade IV toxicity. Neurotoxicity did not exceed grade II (12%). All patients completed radiotherapy and were operated on as scheduled. Twenty-one of 25 patients had the tumour down-staged after chemoradiation with seven (28%) pathological complete responses and 12 (48%) residual tumours limited to ypT1-2N0.

CONCLUSIONS

Weekly OXA, at doses potentially active systemically, can be combined with full-dose, infused FUra and radiotherapy. Given the low toxicity and promising activity, this regimen is being compared to standard FUra-based pelvic chemoradiation in a randomised study.

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. Up to 10 microM, EGCG does not modify the cell-surface immuno-localization of MMP-2, one of the invasion-instrumental proteinases; but while in default culture conditions these cells secrete mainly pro-MMP-2, in the presence of reconstituted basement membrane (Matrigel) they release almost exclusively pro-MMP-9. In contrast, when stimulated to traverse Matrigel toward a chemo-attractant, in addition to pro-MMP-9, they secrete pro-MMP-2. In the presence of 0.2 microM EGCG, only the level of the latter is markedly lowered in the conditioned medium, in parallel with the invasive behavior (>50%). In vivo, s.c. injection of TRAMP-C1 cells dispersed in Matrigel gives origin to a tumor mass, whose growth is not inhibited by green-tea regimen. This growth is contained greater than two-thirds by LPS-triggered polymorpho-nuclear phagocyte (PMN) recruitment but this effect is abolished by green tea. Nevertheless, while tumor-released pro-MMP-2 is activated by co-incubation of TRAMP-C1 cells with PMNs, in the presence of 10 microM EGCG the activation is almost abolished. These results suggest that inflammatory involvement of prostate carcinoma could be efficaciously prevented by green tea with a concomitant lowering of the invasive potential.

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. In addition to restraint of PSA expression, EGCG was found to inhibit in a dose-dependent manner all the above PSA activities, at concentrations lower than the cytotoxic serine-protease inhibitor PMSF and close to levels measured in the serum following ingestion of green tea. The activity of PSA was suppressed also by the elastase released by the inflammatory leukocytes. These results highlight new PSA activities, suggest gelatin zymography as a new convenient assay for PSA, propose EGCG as natural inhibitor of prostate carcinoma aggressiveness, but also stimulate further investigation on the role of prostatic inflammation.

Dermal fibroblasts from pseudoxanthoma elasticum patients have raised MMP-2 degradative potential

Cultured fibroblasts from the dermis of normal subjects and of Pseudoxanthoma elasticum (PXE) patients were analysed for enzyme activity, protein and mRNA expression of metalloproteases (MMP-2, MMP-3, MMP-9, MT1-MMP) and of their specific inhibitors (TIMP-1, TIMP-2 and TIMP-3). MMP-3, MMP-9 and TIMP-3 mRNAs and proteins failed to be detected in both the medium and the cell layer of both controls and PXE patients. MMP-2 mRNA was significantly more expressed in PXE than in control cell lines, whereas MT1-MMP, TIMP-1 and TIMP-2 mRNAs appeared unchanged. MMP-2 was significantly higher in the cell extracts from PXE fibroblasts than in control cells, whereas differences were negligible in the cell medium. Data suggest that PXE fibroblasts have an increased proteolytic potential, and that MMP-2 may actively contribute to connective tissue alterations in this genetic disorder.

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). At these concentrations, a marked and progressive decline of growth was observed in HT-1080 cells, whereas untransformed endothelial cells were only marginally affected. Hyp-DCHA inhibited in a dose-dependent and noncompetitive manner various proteinases instrumental to extracellular matrix degradation; the activity of leukocyte elastase was inhibited the most (IC50 = 3 micromol/L), followed by cathepsin G and urokinase-type plasminogen activator, whereas that of the matrix metalloproteinases (MMPs) 2 and 9 showed an IC50 > 100 micromol/L. Nevertheless, inhibition of extracellular signal-regulated kinase 1/2 constitutive activity and reduction of MMP-2 and MMP-9 secretion was triggered by 0.5 micromol/L Hyp-DCHA to various degrees in different cell lines, the most in C-26. Inhibition of C-26 and HT-1080 cell chemoinvasion (80 and 54%, respectively) through reconstituted basement membrane was observed at these doses. Finally, in mice that received i.v. injections of C-26 or B16-LU8 cells, daily i.p. administration of Hyp-DCHA-without reaching tumor-cytotoxic blood levels-remarkably reduced inflammatory infiltration, neovascularization, lung weight (-48%), and size of experimental metastases with C-26 (-38%) and number of lung metastases with B16-LU8 (-22%), with preservation of apparently healthy and active behavior. These observations qualify Hyp-DCHA as an interesting lead compound to prevent and contrast cancer spread and metastatic growth.

4-Alkylidene-azetidin-2-ones: novel inhibitors of leukocyte elastase and gelatinase

In addition to their antibiotic potency, beta-lactams have recently been investigated as inhibitors of serine proteinase such as leukocyte elastase (LE), released by inflammatory cells. We describe the synthesis of a series of 4-alkylidene-beta-lactams, and investigate how substitutions on C-3, C-4, and N-1 of the beta-lactam ring affect the activity of human LE and gelatinases MMP-2 and MMP-9. LE activity was measured using a chromogenic substrate, while gelatin-zymography assay was used to evaluate gelatinase activity. We demonstrate that C-4 unsaturation on the beta-lactam ring determines the degree of biological activity, with a selectivity over LE by 3-[1-(tert-butyldimethylsilyloxy)-ethyl] derivatives (lowest IC(50) was 4 microM), and over gelatinase MMP-2 by C-3-unsubstituted 4-[1-ethoxycarbonyl]-ethylidene-beta-lactams (lowest IC(50) was 60 microM). (3S)-3-[(1R)-1-hydroxyethyl]-4-(1-ethoxycarbonyl)-ethylidene-azetidin-2-one inhibits gelatinase MMP-9. The compounds tested showed no cytotoxicity against NIH-3T3 murine fibroblasts. This is the first example of beta-lactams inhibiting metallo-proteinases instrumental in cancer invasion and angiogenesis. These molecules are good candidates for prototype drugs showing selective antibiotic, anti-inflammatory, and anti-invasion properties.

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. (-)Epigallocatechin-3-gallate (EGCG), the main flavanol in green tea and known to inhibit inflammation and tumor invasion, exerts dose-dependent inhibition of degradation of gelatin (IC(50)<20 micro M) and casein, which is directly triggered by PR-3. The presence of EGCG does not modify the colocalization of MMP-2 and exogenous PR-3 at the cell surface and does not restrain secreted pro-MMP-2 and pro-MMP-9 activation or degradation of a specific, synthetic peptide by PR-3. These results add new activities to the list of those exerted by PR-3 and indicate a differential inhibition as a result of EGCG.

Dual Action of NAMI-A in inhibition of solid tumor metastasis: selective targeting of metastatic cells and binding to collagen

NAMI-A is a ruthenium complex endowed with a selective effect on lung metastases of solid metastasizing tumors. The aim of this study is to provide evidence that NAMI-A's effect is based on the selective sensitivity of the metastasis cell, as compared with other tumor cells, and to show that lungs represent a privileged site for the antimetastatic effects. The transplantation of Lewis lung carcinoma cells, harvested from the primary tumor of mice treated with 35 mg/kg/day NAMI-A for six consecutive days, a dose active on metastases, shows no change in primary tumor take and growth but a significant reduction in formation of spontaneous lung metastases. Transmission electron microscopy examination of lungs and kidney shows NAMI-A to selectively bind collagen of the lung extracellular matrix and also type IV collagen of the basement membrane of kidney glomeruli. The half lifetime of NAMI-A elimination from the lungs is longer than for liver, kidney, and primary tumor. NAMI-A bound to collagen is active on tumor cells as shown in vitro by an invasion test, using a modified Boyden chamber and Matrigel, and it inhibits the matrix metallo-proteinases MMP-2 and MMP-9 at micromolar concentrations, as shown in vitro by a zimography test. These data show NAMI-A to significantly affect tumor cells with metastatic ability. Binding to collagen allows NAMI-A to exert its selective activity on metastatic cells during dissemination and particularly in the lungs. These data also stress the wide spectrum of daily doses and treatment schedules at which NAMI-A is active against metastases.

Preliminary evaluation of inhibition of matrix-metalloprotease MMP-2 and MMP-9 by Passiflora edulis and P foetida aqueous extracts

Fruit's decoctions of Passiflora edulis and P. foetida var. albiflora were evaluated for the inhibition of activity of gelatinase MMP-2 and MMP-9, two metallo-proteases involved in the tumour invasion, metastasis and angiogenesis. Both water extracts, at different concentrations, inhibited the enzymes.

Modulation of proteolytic potential and differentiation by CNTF and BDNF in two mouse neuroblastoma clones: relation to invasion

The effect of CNTF and BDNF on a proteolytic complement instrumental to invasion and on differentiation was studied in two murine neuroblastoma clones, N1 and N7. At the membrane level, gelatinase MMP-2--mainly the activated form--was restrained by CNTF and BDNF to a residual 34% with both factors; membrane-type 1 MMP was down-regulated to 50% (10 h) and 34% (24 h) with both factors; and urokinase-type plasminogen activator was restrained mainly by BDNF to 70%. In the medium, the two gelatinases MMP-2 and MMP-9 were mainly in zymogen form: only MMP-2 was restrained in N1 cells, while only MMP-9 was restrained in N7 cells by both factors, single or in combination. These effects were paralleled by the induction of neurite outgrowth, which was more stimulated in the less differentiated clone. These dose-dependent and transient effects make CNTF and BDNF ideal candidates for constraining the potentially invasive behavior of nervous system tumors.

(-)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. Cytofluorimetry and immunolocalization revealed that EGCG does not impair MT1-MMP/TIMP-2/MMP-2 presence on the cell membrane. In the membrane extract of HT-1080 human fibrosarcoma cells, 10 micro M EGCG caused a strong increase in MT1-MMP level and accumulation of pro-MMP-2 while leaving activated MMP-2 unchanged. EGCG thus exerts inhibition of MT1-MMP, which restrains activation of MMP-2; this may confer the antiangiogenic and antimetastatic activity associated with green tea.

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. Gelatinase activity was measured using the gelatin-zymography assay, and its inhibition showed that three hydroxyl groups at the A or B ring, or, for non-planar molecules, a galloyl moiety at C3 could be determinant. This comparative study is proposed as a basis for designing new molecules with enhanced anti-proteolytic activities, and no or reduced side-effects, for use in hindering inflammation, cancer invasion and angiogenesis.

Inhibition of endothelial cell functions and of angiogenesis by the metastasis inhibitor NAMI-A

NAMI-A is a ruthenium-based compound with selective anti-metastasis activity in experimental models of solid tumours. We studied whether this activity was dependent on anti-angiogenic ability of NAMI-A. We thus investigated its in vitro effects on endothelial cell functions necessary for angiogenesis to develop, as well as its in vivo effects in the chick embryo chorioallantoic membrane model. Endothelial cell proliferation, chemotaxis, and secretion of the matrix-degrading enzyme metalloproteinase-2 were inhibited by NAMI-A in a dose-dependent manner, and without morphologic signs of cell apoptosis or necrosis. Lastly, NAMI-A displayed a dose-dependent in vivo anti-angiogenic activity in the chorioallantoic membrane model. These data suggest that the anti-angiogenic activity of NAMI-A can contribute to its anti-metastatic efficacy in mice bearing malignant solid tumours.

(-)Epigallocatechin-3-gallate inhibits leukocyte elastase: potential of the phyto-factor in hindering inflammation, emphysema, and invasion

Flavanol (-)epigallocatechin-3-gallate is shown to be a potent natural inhibitor of leukocyte elastase that may be used to reduce elastase-mediated progression to emphysema and tumor invasion. This phyto-factor, abundant in green tea, exerts a dose-dependent, noncompetitive inhibition of leukocyte elastase at a noncytotoxic concentration and is effective in neutrophil culture. This inhibition shows an IC(50) of 0.4 microM, 30 times higher than the alpha1-protease inhibitor but lower than other known natural and synthetic elastase inhibitors. The flavanol inhibits leukocyte elastase at concentrations of 50, 150, and 2500 times lower than that effective on gelatinases (MMP-2 and MMP-9), thrombin, and cathepsin G, respectively, and also blocks elastase-mediated activation of MMP-9.

Tumor gelatinases and invasion inhibited by the green tea flavanol epigallocatechin-3-gallate

BACKGROUND

Given the association of consumption of green tea with prevention of cancer development, metastasis, and angiogenesis, the effect of the main flavanol present, epigallocatechin-3-gallate (EGCG), on two gelatinases most frequently overexpressed in cancer and angiogenesis (MMP-2 and MMP-9) and on tumor cell invasion and chemotaxis were examined.

METHODS

Zymography, Western blotting, and enzyme linked immuoadsorbent assay were used to analyze the effect of EGCG on MMP-2 and MMP-9 activity, whereas its effect on tumor cell invasion and chemotaxis was examined using modified Boyden chamber assays.

RESULTS

A Zn2+ chelation-independent, dose-dependent, noncompetitive inhibition by EGCG of both gelatinases was found at concentrations 500 times lower than that reported to inhibit urokinase. Tumor cell invasion of a reconstituted basement membrane matrix, but not chemotaxis, was reduced by 50% with EGCG concentrations equivalent to that in the plasma of moderate green tea drinkers, and 2 orders of magnitude below those of tissue inhibitors of MMPs. Although higher concentrations of EGCG were associated with increased levels of both cell-associated gelatinases and their activator MT1-MMP, no increased gelatinase activation was found, and TIMP-1 and TIMP-2 inhibitors were up-regulated. Finally, concentrations of EGCG active in restraining proliferation and inducing apoptosis of transformed cells were more than 100 times lower than those reported for normal cells.

CONCLUSIONS

Epigallocatechin-3-gallate is a potent inhibitor of gelatinases and an orally available pharmacologic agent that may confer the antiangiogenic and antimetastatic activity associated with green tea.

Augmented membrane type 1 matrix metalloproteinase (MT1-MMP):MMP-2 messenger RNA ratio in gastric carcinomas with poor prognosis

The activation of zymogen and the amount of proteinase and its inhibition are important in determining the eventual activity of matrix-degrading enzymes involved in tumor aggressiveness. To evaluate a gene complement leading to matrix metalloproteinase 2 (MMP-2; Mr 72,000 gelatinase) activity, membrane type 1 MMP (MT1-MMP), urokinase-type plasminogen activator, MMP-2, and tissue inhibitor of metalloproteinase 2 transcriptional levels were measured in gastric carcinoma biopsies. Comparative tumor:normal tissue reverse transcription-PCR in a cohort of 25 patients revealed up to a 10-fold difference in the expression of MT1-MMP, a metalloproteinase that has been proposed as a membrane receptor activator of MMP-2; a 1-unit increment resulted in a 30% risk to survival. A 20% risk also resulted from a 1-unit increment in the MT1-MMP: MMP-2 ratio, which showed differences of up to 15-fold. Instead, the expression of urokinase-type plasminogen activator, which trips off a cascade ending in the activation of MMP-2, as well as the expression of MMP-2 itself and its inhibitor, tissue inhibitor of metalloproteinase 2, lacked correlation with patient follow-up. Zymography revealed MMP-2 activities that were often in conflict with the transcription results and also with follow-up. The results suggest the evaluation of MT1-MMP and/or MT1-MMP:MMP-2 transcription as a new preoperative molecular-level prognostic factor for gastric carcinoma.