Photosensitization with zinc (II) phthalocyanine as a switch in the decision between apoptosis and necrosis

Photodynamic therapy (PDT) of tumors and other diseases is based on the uptake of a photosensitizing dye in target cells, which are damaged by reactive oxygen intermediates generated on irradiation with light in which the wavelengths match the dye absorption spectrum. PDT can induce cell death by necrosis and apoptosis both in vivo and in vitro, but the factors determining the contribution of either mechanism to the overall process are not completely defined. Our studies on the photosensitization of 4R transformed fibroblasts with the second-generation photosensitizer zinc (II) phthalocyanine (ZnPc) aim at determining the effect of important experimental parameters such as time of cell incubation (2 or 24 h) with ZnPc before irradiation and ZnPc concentration in the incubation medium on cell death. Furthermore, we propose possible correlations between the cell death mechanism and primary photo-damage sites; these are mainly determined by the intracellular localization of the photosensitizer. The mechanism of cell death was determined by both electron microscopy analysis of the morphological alterations induced by photosensitization and measurement of caspase 3 activation. The initial photodamage sites were determined by measuring the activities of several functions typical of mitochondria, lysosomes, Golgi apparatus, cytosol, and plasma membrane. The intracellular localization of ZnPc after 2- or 24-h incubation was determined by fluorescence microscopy. Necrosis, associated with early loss of plasma membrane integrity and complete depletion of intracellular ATP, represents the prevailing mode of death for 4R cells dark-incubated for 2 h with ZnPc and irradiated with light doses reducing viability by 99.9%. In contrast, irradiation performed 24 h after ZnPc incubation causes only partial inhibition of plasma membrane activities, and cell death occurs largely by apoptosis. ZnPc is mainly localized in the Golgi apparatus after 2- and 24-h incubation, and in all of the cases this compartment represents a primary target of photodamage. Only after prolonged incubation is mitochondrial localization of ZnPc clearly detected by fluorescence microscopy; this could be a determining factor for promotion of apoptosis. Our data demonstrate that it is possible to modulate the mechanism of cell death by appropriate protocols; this may be relevant for enhancing the therapeutic efficacy of PDT.

Monocyte/mesangial cell interactions in high-glucose co-cultures

BACKGROUND

Monocytes bind to human mesangial cells (HMC) in a co-culture model of leukocyte/ glomerular cell interactions. Since monocytic infiltration has been demonstrated in the early stages of diabetic glomerulopathy, we examined whether co-culture with myelomonocytes of the U937 cell line in media mimicking the diabetic microenvironment modulated phenotype, growth, and extracellular matrix production patterns of HMC.

METHODS

HMC monolayers grown for 5 days in 5.5 mmol/l (NG) or 30 mmol/l (HG) glucose media were examined 3, 24 and 48 h after addition of U937 cells by computer-assisted image analysis/fluorescence microscopy following fixation, staining for cell adhesion, and TUNEL/propidium iodide labelling for apoptosis. As matrix components may be relevant to both phenotype of cultured HMC and monocyte adhesion, reverse transcription-polymerase chain reaction, zymography, and ELISA were used to detect urokinase-plasminogen activator (uPa), collagen type IV (COL IV), transforming growth factor beta1 (TGF-beta1), matrix metalloproteinases (MMP), and relative inhibitors (tissue inhibitor of MMP (TIMP)) expression in co-cultures in NG/HG.

RESULTS

U937 adhesion at 1-3 h was increased in HG (from 54.9+/-6.6 to 87.1+/-5.8% U937/HMC). Control HMC proliferating in NG supplemented with 10% fetal bovine serum had an average cross-sectional area of 9993+/-505 micro(2) with 1.2+/-0.1 hillocks/high-power field, which increased to 13 651+/- 1114 micro(2) with 0.5+/-0.2 hillocks/high-power field in HG (P<0.05). TUNEL+HMC were nearly identical (4.9+/-1.7 vs 4.2+/-0.4% in HG, P=NS). Enhanced transcription and secretion of urokinase (uPA, +656%), COL IV (+137%), TGF-beta1 (+590%) were observed in co-cultures in HG. COL IV and TGF-beta1, but not uPA, were also increased in HMC alone, exposed to HG for 5 days. MMP-2/TIMP-2 ratio was decreased while MMP-1/TIMP-1 was increased in HG co-cultures. In both NG and HG, U937 adhesion reduced HMC number and hillocks at 24 h, with constant apoptosis. The effects of U937 were no longer detectable at 48 h, when apoptosis was 2.1+/-0.6 vs 4.0+/-0.4% in HG, and cell counts returned above basal, possibly due to a delayed proliferative response.

CONCLUSIONS

High glucose medium increases U937 cell adhesion to HMC. In turn, monocytes modulate number and spatial distribution of HMC, which are also markedly affected by ambient glucose levels. These interactions may be relevant to leukocyte infiltration, mesangial expansion, and glomerulosclerosis in diabetes.

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.

TNF-Induced shedding of TNF receptors in human polymorphonuclear leukocytes: role of the 55-kDa TNF receptor and involvement of a membrane-bound and non-matrix metalloproteinase

A down-modulation of both the 55-kDa (TNF-R55) and the 75-kDa (TNF-R75) TNF receptors is observed in neutrophils exposed to a variety of stimuli. Proteolytic cleavage of the extracellular region of both receptors (shedding) and, with TNF, internalization of TNF-R55 and shedding of TNF-R75 are the proposed mechanisms. We have characterized the TNF-induced shedding of TNF receptors in neutrophils and determined the nature of the involved proteinase. Neutrophils exposed to TNF release both TNF receptors. A release of TNF receptors comparable to that observed with TNF was induced with TNF-R55-specific reagents (mAbs and a mutant of TNF) but not with the corresponding TNF-R75-specific reagents. A hydroxamic acid compound (KB8301) almost completely inhibited shedding of TNF-R55 and to a lesser degree shedding of TNF-R75. KB8301 also inhibited FMLP-induced shedding to a similar extent. Shedding was also inhibited by 1,10-phenanthroline, but this effect was considered nonspecific as the compound, at variance with KB8301, almost completely inhibited TNF and FMLP-induced PMN activation. Diisopropylfluorophosphate partially inhibited shedding of TNF-R75, suggesting the contribution of a serine proteinase to the release of this receptor. Shedding activity was not affected by matrix metalloproteinases inhibitors nor was it released in the supernatants of FMLP-stimulated neutrophils. These results suggest that TNF induces release of its receptors, that such a release is mediated via TNF-R55, and that a membrane-bound and non-matrix metalloproteinase is involved in the process. The possibility that ADAM-17, which we show to be expressed in neutrophils, might be the involved proteinase is discussed.

Mesangial cell proliferation in long-term streptozotocin-induced diabetes mellitus in the rat and the renoprotective activity of heparin

At present, it is not clear whether mesangial proliferation underlies mesangial expansion in diabetic nephropathy. To address this issue and the relationship between heparin's renoprotective and antimitogenic activities, we studied three streptozotocin-induced diabetic rat groups 5 and 12 months after diabetes induction: two groups were administered a modified heparin, each with a different protocol, and two healthy rat groups, one of which was treated with the same heparin, served as controls. Untreated diabetic animals developed clear evidence of nephropathy, namely expansion of the glomerular extracellular matrix, as expressed by glomerular basement membrane thickening, and increased mesangial deposition of type IV collagen. These alterations were prevented/cured by heparin treatment. Kidney sections were processed immunohistochemically for proliferating cell nuclear antigen and smooth muscle alpha-actin which is expressed only by proliferating mesangial cells. The number of proliferating cell nuclear antigen positive nuclei and alpha-actin-positive cells per glomerulus did not differ between groups at both 5 and 12 months. In conclusion, there is no evidence that mesangial proliferation is increased in late experimental diabetic nephropathy, and heparin seems to be renoprotective through mechanisms other than antiproliferation.

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.

Expression study on D123 gene product: evidence for high positivity in testis

A novel 44-kDa gene product (D123) has been proposed as necessary for S-phase entry of the cell cycle: a point mutation resulted in a temperature-sensitive arrest in G1-phase. From human fibrosarcoma cDNA library, we have isolated an identical gene and studied its sequence and mRNA and protein expression. Compared with D123, three nucleotide differences within the human coding sequence, plus others, result in a change of two amino acids. A partial sequence similarity has been found with a yeast gene of unknown function. The protein has several potential phosphorylation sites, is highly hydrophilic, and may be highly structured in alpha-helix. The mRNA is abundantly expressed by a variety of normal and transformed cells and by all tissues examined, being most highly expressed in testis. Specific antibodies, raised against a rhD123 polypeptide, recognize a major 42- to 44-kDa molecule in crude extract of various human cell lines. Immunohistochemistry reveals that D123 protein is not homogeneously expressed: it is detected, often in granular vescicles, in the cytoplasm of some epithelial, stromal, and sperm cells and in varicosities lining nervous fibers, while it appears to be absent in nuclei, endothelial, and smooth muscle cells. The precise link between cytoplasmic occurrence of D123 and cell cycle progression still remains to be clarified.

Photosensitization of cells with different metastatic potentials by liposome-delivered Zn(II)-phthalocyanine

The phototoxicity of liposome-incorporated Zn(II)-phthalocyanine (ZnPc) and its water-soluble tetrasulphonated derivative (ZnPcTS) was studied in the tumorigenic but nonmetastatic (RE4) and the highly metastatic (4R) transformed rat embryo fibroblasts. Upon irradiation with 585-605 nm light in the presence of ZnPc, the cell survival drastically decreased, while it was unaffected by ZnPcTS. Enzymatic assays showed that ZnPc induced about a 60% decrease in the activity of the mitochondrial enzymes NADH and succinate dehydrogenase after 3 min of irradiation, while no significant reduction in the activity of lactate dehydrogenase and lysosomal N-acetyl-beta-glucosaminidase was observed. The transport of thymidine, deoxyglucose and alpha-aminoisobutyric acid through the plasma membrane was strongly inhibited after irradiation. Similarly, the intracellular ATP content was significantly reduced. The reduction of DNA biosynthesis showed a time dependence quite similar to the photo-induced decrease in cell survival. No repair of cellular functions affected by ZnPc was observed in the 2 cell lines. These results indicate that, under our experimental conditions, hydrophobic ZnPc exerts its cytotoxic activity mainly by impairing those functions localized in the plasma membrane of the cells.

Suppression of metastatic potential and up-regulation of gelatinases and uPA in LLC by protracted in vivo treatment with dacarbazine or razoxane

Treatment of mouse Lewis lung carcinoma with razoxane or dacarbazine was protracted for 10 transplant generations. While the capacity of the treated tumors to grow locally in immuno-competent or in immuno-depressed hosts was retained and not significantly modified, the metastatic phenotype was eliminated when the treated tumor cells were transplanted into immuno-competent hosts. The reduction in metastatic potential was slightly less pronounced, in terms of both number and volume of metastases, when the treated tumor cells were transplanted into immuno-depressed hosts. These properties were retained after 3 transplant generations without treatment. Northern blotting and zymography of primary-tumor crude extracts revealed that treatment with either razoxane or dacarbazine for one generation approximately doubled the expression of MMP-2 and MMP-9, while lacking any effect on that of 1.0 and of 3.5 kb TIMP-2. When the treatment was maintained for 10 generations, the expression of MMP-2 and MMP-9 for both drugs showed up-regulation of approximately 10- and 2-fold respectively. TIMP-2 mRNA of 1.0 kb doubled its expression, while that of 3.5 kb registered just above the control. Dacarbazine doubled the expression of uPA after 10 generations, while razoxane boosted it approximately 3-fold after either 1 or 10 generations. The permanent loss of metastatic phenotype induced in Lewis lung carcinoma by dacarbazine and razoxane is thus attributable to biological mechanisms independent of down-regulation of expression and/or activation of the 2 gelatinases.

CNTF up-regulation of TIMP-2 in neuroblastoma cells

The ciliary neurotrophic factor (CNTF) can regulate survival and differentiation of many types of developing and adult neurons; in metastatic SK-N-BE neuroblastoma cells, it promotes differentiation and neurite outgrowth. The expression of Gelatinase A (MMP-2) and its specific tissue inhibitor (TIMP-2), a degradative system whose balance is involved in matrix invasion and metastasis, was investigated in SK-N-BE cells cultured with and without CNTF or NGF. Zymographic analysis of conditioned media revealed that the cells constitutively secrete two gelatinases, mainly pro-MMP-2 but also traces of pro-MMP-9. In a time-course experiment in the presence of 25 ng/ml of CNTF, the MMP-2 mRNA expression showed no significant modulation, while TIMP-2 mRNA up-regulated to > 2-fold after 48 h and then fell dramatically. At the same concentrations, NGF showed no effect. TIMP-2 mRNA expression showed a dose-dependent increase of up to 8-fold from 1 to 250 ng/ml of CNTF and increased secretion of TIMP-2 was confirmed by Western blotting. MMP-2 was only slightly over-expressed under the same conditions, at either mRNA or protein level, with no correlation with neurocytokine concentration. These results suggest that boosting the expression of TIMP-2 by CNTF could restrain both matrix degradation following nervous system injury and neuroblastoma aggressiveness.

Control of type IV collagenase activity by components of the urokinase-plasmin system: a regulatory mechanism with cell-bound reactants

The urokinase-type plasminogen activator (uPA) and the matrix-degrading metalloproteinases MMP-2 and MMP-9 (type IV collagenases/gelatinases) have been implicated in a variety of invasive processes, including tumor invasion, metastasis and angiogenesis. MMP-2 and MMP-9 are secreted in the form of inactive zymogens that are activated extracellularly, a fundamental process for the control of their activity. The physiological mechanism(s) of gelatinase activation are still poorly understood; their comprehension may provide tools to control cell invasion. The data reported in this paper show multiple roles of the uPA-plasmin system in the control of gelatinase activity: (i) both gelatinases are associated with the cell surface; binding of uPA and plasmin(ogen) to the cell surface results in gelatinase activation without the action of other metallo- or acid proteinases; (ii) inhibition of uPA or plasminogen binding to the cell surface blocks gelatinase activation; (iii) in soluble phase plasmin degrades both gelatinases; and (iv) gelatinase activation and degradation occur in a dose- and time-dependent manner in the presence of physiological plasminogen and uPA concentrations. Thus, the uPA-plasmin system may represent a physiological mechanism for the control of gelatinase activity.

Recombinant human TIMP-3 from Escherichia coli: synthesis, refolding, physico-chemical and functional insights

Matrix metalloproteinases are inhibited by a growing family of specific tissue inhibitors, TIMPs. The cDNA of the third member of the family, TIMP-3, was obtained by using a reverse transcription-polymerase chain reaction (RT-PCR) to amplify the corresponding mRNA from human placenta. Cloning and expression of the TIMP-3 were performed in Escherichia coli as a fusion protein with a 36 amino acid N-tail containing a His cluster. In the host vector system, rhTIMP-3 was stored intracellularly in its denatured, insoluble form in inclusion bodies. Slow dilution of denaturing and reducing agents, from rhTIMP-3 His bound to a metal affinity solid phase, was followed by partial acid removal of the N-tail, which leaves a residue of four amino acids. Circular dichroism, fluorescence and second-derivative UV spectroscopic analyses supported correct refolding of the recombinant and zymography showed inhibition of both MMP-2 and MMP-9 gelatinolytic activities. The role of the C-terminus, which has closer homology with TIMP-2 than TIMP-1, was also investigated: a C-truncated mutant, similarly cloned and expressed in E. coli, shows complete lack of inhibitory activity on MMP-9, still retaining some on MMP-2. The described protein engineering shows high yield of active inhibitor, unglycosylated as in the native form.

Effect of glucose and heparin on mesangial alpha 1(IV)COLL and MMP-2/TIMP-2 mRNA expression

Mesangial cells are responsible for the synthesis of mesangial matrix as well as its degradation, which is mediated by a number of proteolytic activities, including metalloproteinases (MMPs). Imbalanced matrix protein metabolism may be responsible for mesangial expansion and glomerulosclerosis in diabetic nephropathy. Heparin prevents this complication. In human and murine mesangial cell cultures, RT-PCR was able to detect mRNA expression for a number of molecules involved in the mesangial extracellular matrix turnover: type IV collagen [alpha 1(IV)COLL], MMP-1, MMP-2, MMP-3, MMP-9 and MMP-10, and the tissue inhibitors TIMP-1 and TIMP-2. The expression of mRNA for alpha 1(IV)COLL and MMP-2/TIMP-2 balance was studied in human cells in the presence of high glucose and heparin. mRNAs for all the studied molecules were expressed at different levels. Interestingly, a shift in the balance of alpha 1(IV)COLL, MMP-2 and TIMP-2 was observed in high glucose, which was partially reversed by heparin supplementation. The new equilibrium was mostly due to the down-regulation of type IV collagen expression, rather than further reduction of potential proteolysis. Our data, while extending the list of potential mediators of mesangial matrix catabolism, highlight a molecular mechanism by which the pathogenesis of diabetic nephropathy may be sustained, and at the same time suggest that heparin may have the potential to correct this abnormality.

Down-regulation of tumour gelatinase/inhibitor balance and preservation of tumour endothelium by an anti-metastatic ruthenium complex

The anti-metastatic ruthenium complex Na[trans-RuCl4(DMSO)Im] was given i.p. at 22 and 44 mg/kg/day, on days 8-13 after tumour implantation, to mice carrying s.c. implants of MCa mammary carcinoma. The aim of the study was to compare the effects on lung metastasis formation with those on primary tumour cells. This investigation was based on flow cytometry analysis after propidium iodide and acridine orange staining, histology of tumour parenchyma and RT-PCR analysis for the type-IV collagenases MMP-9 and MMP-2 and their respective inhibitors TIMP-1 and TIMP-2 mRNAs. Na[trans-RuCl4(DMSO)Im] is not cytotoxic for tumour cells but has the capacity of interacting with nucleic acids, giving a general reduction of nucleic acid content as shown by a marked reduction of acridine orange staining and a tendency to a reduction of DNA polyploidy with marked reduction of 8n and 4n cell populations. Na[trans-RuCl4(DMSO)Im] also influences a proteolytic system which has the potential of degrading the basement membrane and has been related to metastatic aggressiveness: it markedly reduces, in a dose-dependent manner, MMP-2/TIMP-2 balance, but not that of MMP-9/TIMP-1. The different enzyme/inhibitor mRNA levels between untreated and treated tumours seem to be unaffected by tumour-infiltrating lymphocytes and are paralleled by the maintenance of connective tissue around blood vessels in the tumour mass. Correspondingly, lung metastasis formation is markedly reduced, to less than 10% of that seen in controls.

72-kilodalton type IV collagenase, type IV collagen, and Ki 67 antigen in serous tumors or the ovary: a clinicopathologic, immunohistochemical, and Serological study

The immunohistochemical expression of 72-kDa type IV collagenase [matrix-metalloproteinase (MMP)-21], basement membrane component type IV collagen and proliferation-related antigen Ki 67 were investigated in 43 benign, borderline, and malignant serous tumors of the ovary. The results were compared with the histotypes of ovarian serous tumors and with their clinical behavior. Serum evaluation of MMP-2 was performed in 14 patients with cystadenocarcinoma and the data compared with that of a control group. The basement membrane (BM) was continuous in benign cystadenomas and in some borderline tumors, whereas it was discontinuous or absent in other borderline tumors, in borderline tumors with microinvasion, and cystadenocarcinomas. The percentage of MMP-2- and Ki 67-expressing cells increased from cystadenomas to borderline tumors, being the highest in malignant tumors; a frequent basal disposition of the MMP-2 cytoplasmic granules also was observed in cystadenocarcinomas. Statistical analysis demonstrated that MMP-2 expression was inversely related to BM integrity. Serum MMP-2 values did not differ from that of the control group. Cox regression analysis showed that tumor stage and grade were significant prognostic factors, whereas MMP-2 and Ki 67 immunohistochemical expression added no further significant information to the prognosis. The investigators conclude that the correlation between increasing MMP-2 expression and BM alteration gives support to the hypothesis of a direct role of the metalloproteinase in the process of destructive stromal invasion. MMP-2, type IV collagen, and Ki 67 immunodetection varied according to the histologic classification of ovarian serous tumors. However, neither these factors nor the serum evaluation of MMP-2 appear useful as prognostic predictors in this series.

Interaction of hydro- or lipophilic phthalocyanines with cells of different metastatic potential

A highly metastatic (4R) and a nonmetastatic (RE4) transformed rat embryo fibroblast cell line were incubated with lipid-soluble Zn(II)-phthalocyanine (ZnPc) and its water-soluble tetrasulphonated derivative (ZnPcTS) and compared for phthalocyanine uptake. The hydrophobic liposome-delivered ZnPc showed a significantly greater uptake by both cell lines than did ZnPcTS. Moreover, the two phthalocyanines appear to interact with cells according to different pathways, as suggested by the different temperature-dependence of the binding process and the different inhibitory action exerted by selected serum proteins, such as lipoproteins and heavy proteins. Under all experimental conditions, the two cell lines exhibited similar interactions with ZnPc and ZnPcTS, suggesting that heterogeneity of the tumor cell population has a minor influence on the accumulation of photosensitizers.

Gelatinase A/TIMP-2 imbalance in lymph-node-positive breast carcinomas, as measured by RT-PCR

Over-production of gelatinase A (MMP-2) or under-production of its inhibitor (TIMP-2) may result in the matrix degradation crucial for metastasis, and early evaluation of their expression in primary tumor would offer important prognostic informations. RT-PCR amplicons of MMP-2 and TIMP-2 mRNA from tissue biopsies of 13 breast carcinomas and one fibrocystic mastopathy were quantitated. In comparison with their normal-tissue counterparts, their expression trends were not uniform: in some cases MMP-2 increased in the tumor without changes in TIMP-2, in others TIMP-2 expression also increased, although to a lesser extent than MMP-2; only in 2 cases was it slightly lower in the tumor tissue. Nevertheless, clearer insights were gained from the comparison of the ratio (R) between MMP-2tumor/normal and TIMP-2tumor/normal: as in the fibrocystic mastopathy, the R in carcinomas without lymph-node involvement (LN-) was usually lower than I in most cases. In contrast, in 5 out of 6 patients with lymph-node metastasis (LN+), the ratio ranged between 2 and 4. While the R magnitude was not related to the frequency of positive lymph nodes out of the total analyzed, nor to relapse status at follow-up (all relapse-free), the clear-cut difference between the LN- and LN+ groups was statistically significant. Results suggest that evaluation of MMP-2/TIMP-2 mRNA balance may constitute an early prognostic approach, which may also be more reliable concerning cancer aggressiveness as compared with the MMP-2 alone, and that boosting TIMP-2 expression may be a therapeutic strategy to prevent metastasis.

Tissue and serum metalloproteinase (MMP-2) expression in advanced ovarian serous cystoadenocarcinomas: clinical and prognostic implications

OBJECTIVE

The object of this study was to analyse the tissue and serum metalloproteinase (MMP-2), an enzyme which degrades the basement membrane collagen type IV, as a potential marker useful in prognostic evaluation and clinical monitoring of the follow-up, in patients with advanced ovarian serous cystadenocarcinoma.

MATERIALS AND METHODS

Tissue MMP-2 expression was determined in 21 FIGO stage III ovarian serous cystadenocarcinomas treated with primary surgery and adjuvant chemotherapy, and compared to 10 cystadenomas used as controls. Retrospective analysis of clinical data allowed the comparison of accepted prognostic factors to tissue MMP-2 expression for impact on disease-free survival. In fourteen out of 21 patients, serum MMP-2 levels were also analysed.

RESULTS

Compared to cystadenomas, the tissue MMP-2 expression was significantly (P < 0.001) higher in serous cystadenocarcinomas. A significant relationship was observed between tissue MMP-2 and disease-free survival (P = 0.0003), independently of tumor architectural grade, lymph nodal status and residual disease after debulking surgery. Recurrence risk in patients whose carcinomas had a tissue MMP-2 > or = 29% was significantly higher than that in patients whose carcinomas demonstrated lower tissue MMP-2 expression (P = 0.004). Serum MMP-2 levels correlated with tissue staining, and also expressed a significant relationship with disease-free survival (P = 0.002).

CONCLUSIONS

Tissue MMP-2 seems to be a prognostic indicator in patients with FIGO stage III ovarian serous cystadenocarcinoma, significantly correlated with recurrence risk and apparently independent of tumor architectural grade, lymph nodal status, and residual disease after debulking surgery. An interesting relationship was observed between tissue staining and MMP-2 serum levels.

Expression of TNF receptors by T cells and membrane TNF-alpha by alveolar macrophages suggests a role for TNF-alpha in the regulation of the local immune responses in the lung of HIV-1-infected patients

High amounts of TNF-alpha are released by alveolar macrophages (AMs) in the lungs of patients with HIV-1 infection. To investigate the role of this cytokine in the local immune response, we studied the expression of surface receptors for TNF-alpha (TNF-Rs) and the presence of the transmembrane form of TNF-alpha (mTNF-alpha) on bronchoalveolar lavage (BAL) cells recovered from 14 patients with HIV-1 infection. The role of TNF-alpha both in the events leading to the T cell alveolitis and as a mediator of cytotoxicity was also evaluated. TNF-R expression was determined by flow cytometry on BAL CD8 lymphocytes and AMs (i.e., the cells that account for the alveolitis in HIV-1 infection). We found that CD8 cells express the 75-kDa (CD120a) but not the 55-kDa (CD120a) TNF-Rs, whereas AMs were devoid of TNF-R expression. More than 90% of BAL T cells efficiently bound TNF-alpha; when T cells were tested for their proliferative capacity, an up-regulation of the IL-2-mediated proliferation by TNF-alpha was observed, suggesting that this cytokine may drive the in situ proliferation of CD120b+ T cells. As shown by flow cytometry analysis and immunoprecipitation with anti-TNF-alpha Ab, mTNF-alpha expression was observed on AMs but not on alveolar T cells. Fixed AMs showed high levels of killing against TNF-sensitive targets. Taken together, our data demonstrate the selective expression of TNF-Rs and mTNF-alpha on cells accumulating within the alveolar spaces of patients with HIV-1 infection, pointing to the compound role of TNF-alpha in the local immune responses.

Expression of TNF receptors by T cells and membrane TNF-alpha by alveolar macrophages suggests a role for TNF-alpha in the regulation of the local immune responses in the lung of HIV-1-infected patients

High amounts of TNF-alpha are released by alveolar macrophages (AMs) in the lungs of patients with HIV-1 infection. To investigate the role of this cytokine in the local immune response, we studied the expression of surface receptors for TNF-alpha (TNF-Rs) and the presence of the transmembrane form of TNF-alpha (mTNF-alpha) on bronchoalveolar lavage (BAL) cells recovered from 14 patients with HIV-1 infection. The role of TNF-alpha both in the events leading to the T cell alveolitis and as a mediator of cytotoxicity was also evaluated. TNF-R expression was determined by flow cytometry on BAL CD8 lymphocytes and AMs (i.e., the cells that account for the alveolitis in HIV-1 infection). We found that CD8 cells express the 75-kDa (CD120a) but not the 55-kDa (CD120a) TNF-Rs, whereas AMs were devoid of TNF-R expression. More than 90% of BAL T cells efficiently bound TNF-alpha; when T cells were tested for their proliferative capacity, an up-regulation of the IL-2-mediated proliferation by TNF-alpha was observed, suggesting that this cytokine may drive the in situ proliferation of CD120b+ T cells. As shown by flow cytometry analysis and immunoprecipitation with anti-TNF-alpha Ab, mTNF-alpha expression was observed on AMs but not on alveolar T cells. Fixed AMs showed high levels of killing against TNF-sensitive targets. Taken together, our data demonstrate the selective expression of TNF-Rs and mTNF-alpha on cells accumulating within the alveolar spaces of patients with HIV-1 infection, pointing to the compound role of TNF-alpha in the local immune responses.

Synthesis and refolding of human TIMP-2 from E. coli, with specific activity for MMP-2

Tissue inhibitors of metalloproteinase (TIMPs) are inhibitory counterparts of collagenases, containing 12 cysteine residues paired to six internal disulphide bridges. TIMP-2, an inhibitory protein of 72 kDa gelatinase/type IV collagenase (MMP-2), was expressed in Escherichia coli as a fusion protein with a 34 amino acid NH2-linked tail containing six consecutive histidine residues. The protein was purified in a single-step using an ion metal affinity column (IMAC) in denaturing conditions. The immobilized fusion TIMP-2 protein was refolded at a high concentration in the column, producing about 5 mg of protein per litre of bacterial cells. It shows specific binding and inhibitory activity against MMP-2, but has no effect against 92 and 45 kDa gelatinases.

HIV-1 modulates the expression of gelatinase A and B in monocytic cells

The levels of mRNA of both gelatinases A and B were dramatically decreased in HIV-infected cells, when compared to uninfected cells. The expression of gelatinase A in HIV-infected cells was selectively increased by tumor necrosis factor (TNF alpha) while the expression of gelatinase B was not affected. In contrast, in uninfected cells TNF alpha down regulated gelatinase B mRNA level, without affecting the gelatinase A. N-acethylcysteine (NAC) increased the levels of mRNA of both gelatinases. The conditioned media from HIV-infected and uninfected cells had comparable level of secreted gelatinase A protein. These data suggest that in monocytic cells different regulatory pathways control gelatinases A and B and that HIV could modulate in vivo the expression of these proteolytic enzymes, critically involved in regulation of invasion of basement membrane.