Analyzing the success of the volume-based waste fee system in South Korea.

For more than a decade, South Korea has been ranked first among the OECD (Organization for Economic Cooperation and Development) members in their municipal solid waste (MSW) recycling rate. One of the major contributing factors for its outstanding MSW recycling performance is the volume-based waste fee (VWF) system implemented in 1995. Despite the perceived success of VWF, there has been few research conducted that has sought to demonstrate the success of the policy in an empirical manner. Research conducted currently on VWF in South Korea tends to have limitations in empirical approaches and identifying the intervention effect of VWF on recycling performance. This study attempts to empirically test whether the adoption of VWF positively affected recycling performance in Korea over time. The findings suggest that although there was a dramatic increase of the recycling rate with the introduction of VWF in 1995, Korea's MSW recycling performance settled back again and showed the constant pace after the intervention. No significant differences in recycling rate were found between before and after 1995 period. In conclusion, implications and suggestions for both research and practice are proposed.

Xanthohumol induces different cytotoxicity and apoptotic pathways in malignant and normal astrocytes.

Cytotoxicity and the mechanisms of cell death induced by xanthohumol (XN) were compared in normal and cancerous human cells as the differences may be relevant for the potential use of XN in cancer therapy. The cancer cells seemed to be more susceptible to the cytotoxicity of XN than normal cells, but a significant difference was observed only in astrocytic cells. XN induced a higher rate of apoptosis in glioblastoma cells than in normal astrocytes, which was associated with activation of p53 and an elevated Bax/Bcl-2 ratio in glioblastoma cells, indicating an intrinsic caspase-dependent apoptotic pathway. In contrast, a reduced Bax/Bcl-2 ratio was observed in normal human astrocytes. This was also associated with higher expression of the cell cycle inhibitor, p21, in glioblastoma cells than in normal astrocytes. In addition, at a lower, non-cytotoxic concentration, XN partially inhibited the invasiveness of glioblastoma cells. Due to the selective sensitivity of astrocytic cells to XN, this compound should be studied further as a candidate for adjuvant therapy in the treatment of glioma.

Increases of antibiotic resistance in excessive use of antibiotics in smallholder dairy farms in northern Thailand.

Antibiotic resistance patterns of bacterial isolates from both quarter teat-tip swabs and their quarter milk samples were evaluated in smallholder dairy farms in northern Thailand with excessive use of antibiotics (HIGH) compared with normal use (NORM). Results from teat-tip swab samples showed that the percentage of Bacillus spp. resistance to overall antibiotics was significantly lower in the NORM group than that of the HIGH group, whereas, the resistance percentage of coagulase-negative staphylococci in the NORM group was higher than that of the HIGH one. The overall mastitis-causing bacteria isolated from milk samples were environmental streptococci (13.8%), coagulase-negative staphylococci (9.9%), Staphylococcus aureus (5.4%), and Corynebacterium bovis (4.5%). Both staphylococci and streptococci had significantly higher percentages of resistance to cloxacillin and oxacillin in the HIGH group when compared to the NORM one. An occurrence of vancomycin-resistant bacteria was also observed in the HIGH group. In conclusion, the smallholder dairy farms with excessive use of antibiotics had a higher probability of antibiotic-resistant pattern than the farms with normal use.

[Prognostic implications of biologic markers in intracranial meningiomas: 120 cases]. / Implications pronostiques de différents marqueurs biologiques dans les méningiomes intracrâniens: à propos de 120 cas.

UNLABELLED: The recurrence and progression of treated intracranial meningiomas highlights the problem of the type of follow-up that should be used and whether early complementary treatment is indicated. The aim of this study was to evaluate different biochemical markers involved in cell proliferation and transformation to identify new prognostic factors in intracranial meningiomas. Between 1989 and 2003, 120 intracranial meningiomas were studied biochemically. The levels of estrogen receptors (RE), progesterone receptors (RP), cathepsin B (CB), cathepsin L (CL), stefin A (ATA), stefin B (STB), cystatin C (CYSC), urokinase (u-PA), type 1 plasminogen activator inhibitors (PAI-1), cathepsin D (CD) and thymidine kinase activity (TK) were measured in tumor extracts using biochemical assays. RESULTS: Out of 120 meningiomas, 73 were grade I, 39 grade II and eight grade III according to the WHO classification. Of these patients, 17 showed recurrence. The mean follow-up was 47 months. Monofactorial analysis showed that expression of progesterone receptors (RP) had an inverse correlation with recurrence (p=0.0025 %) and that thymidine kinase activity (TK), cathepsin L (CL), the WHO grade and the degree of tumor resection correlated with recurrence (p<0.05). Principal component analysis and linear discriminant analysis confirmed these results. The results of this study confirm the importance of biological parameters (PR, CL, TK) as prognostic factors for the risk of recurrence in intracranial meningiomas.

Cathepsins B and L and their inhibitors stefin B and cystatin C as markers for malignant progression of benign meningiomas.

Meningiomas are, in general, slowly growing benign tumors attached to the dura mater and composed of neoplastic meningothelial (arachnoidal) cells. They have a wide range of histopathological appearances and are classified, according to the aggressiveness of their growth and the risk of recurrence, as WHO grade I (benign) meningiomas, WHO grade II (atypical) meningiomas and WHO grade III anaplastic (malignant) meningiomas. As invasion of normal tissue may occur in all grades, independent biological markers are needed to identify the more aggressive and recurrent meningiomas. The lysosomal cysteine proteinases, cathepsins B and L, have been associated with tumor invasiveness and the aim of this study was therefore to evaluate them, together with their endogenous inhibitors stefin B and cystatin C, as potential markers for the aggressiveness of meningiomas. The expression of cathepsins B and L and their inhibitors stefin B and cystatin C in 21 benign (grade I) and 9 atypical (grade II) meningiomas has been compared by immunohistochemical staining, QRT-PCR and Northern blot analysis. The protein levels of cathepsins B (p=0.050) and L (p=0.019) were found to be significantly higher in atypical than in benign meningiomas. In contrast, their mRNA levels did not differ, indicating that the synthesis of cathepsins was accelerated at the translational level. Protein and mRNA levels of stefin B (p= 0.007), but not cystatin C, were significantly lower in atypical compared with benign meningiomas. The expression of cathepsins and inhibitors was not different between central and peripheral meningioma tissue or between histological subtypes of meningiomas, with the exception of cathepsin L, the level of which was significantly lower in transitional meningiomas. We conclude that higher protein levels of cathepsins B and L and lower mRNA levels of stefin B are potential diagnostic markers for invasive and aggressive behavior of meningiomas. The diagnostic and prognostic value for relapse of meningioma needs to be confirmed in a larger population of patients.

Comparison of expression of cathepsins B and L and MMP2 in endothelial cells and in capillary sprouting in collagen gel.

The lysosomal cysteine proteinases cathepsins B and L are known to play an important role in the invasive growth of tumor cells, but their association with angiogenesis has been less well studied. The aim of this study was to determine the possible role of endothelial cell-associated cathepsins B and L in induced capillary growth in the aorta ring model of angiogenesis. Specific inhibitors of cysteine proteinases did not inhibit capillary growth in aorta ring culture and only slightly inhibited the degradation of surrounding collagen. In contrast, strong inhibition of both processes by the matrix metalloproteinase inhibitor BB-94 was observed, indicating the importance of endogenous MMP production in angiogenesis. In support of this finding, we demonstrated a significant increase in endogenous endothelial mRNA of MMP2, but not of cathepsins B and L, in proliferating primary human dermal microvascular endothelial cells (HMVEC-d) in culture. However, MMP2 mRNA expression was increased only when the cells were embedded in collagen but not when they were grown on plastic, regardless of the addition of the growth factors VEGF or bFGF. Moreover, on plastic the impairment of MMP2 induction by growth factors was observed. The differential effect of growth factors implies the crosstalk with integrin signaling as a consequence of binding to the different matrix. This study suggests that endothelial cell-associated cathepsins B and L are not involved in the invasive growth of capillaries from existing blood vessels and that the presence of collagen is necessary for MMP2 expression in endothelial cells.

Cathepsin B, plasminogenactivator-inhibitor (PAI-1) and plasminogenactivator-receptor (uPAR) are prognostic factors for patients with non-small cell lung cancer.

To evaluate the possible role of cysteine proteases and serine proteases, as well as their respective inhibitors and receptors, as new prognostic factors in NSCLC, we examined, for the first time, 10 biological parameters related to three proteolytic systems within a homogeneous collective of 147 cases of NSCLC. Activities (cath B(AT), cath B(A7.5)) and protein levels of cath B(C), cath L(C), uPA, PAI-1, uPAR [measured by three different assays uPAR (ADI), uPAR (HD13), uPAR (IIIF10)] and TF were measured in homogenates of lung tumour tissue and corresponding non-malignant lung parenchyma. Total cath B activity (cath B(AT)) and enzymatic activity of the fraction of cath B, which is stable and active at pH 7.5 (cath B(A7.5)), were determined by a fluorogenic assay using synthetic substrate Z-Arg-Arg-AMC. The concentrations of cath B(C), cath L(C), uPA, PAI-1, uPAR and TF were determined by ELISAs. uPAR was determined using three different ELISA formats. The median levels of cath B(AT) (5.1-fold), cath B(A7.5) (2.5-fold), cath B(C), (8.5-fold), cath L(C) (6.6-fold), uPA (6.5-fold), PAI-1 (4.2-fold), uPAR (ADI) (2.2-fold), uPAR (HD13) (4.0-fold) and uPAR (IIIF10) (2.6-fold) were higher in tumour tissue compared to the lung parenchyma. Cath B(AT), cath B(A7.5) and cath B(C) in primary tumours correlated with lymph node metastases. Regarding histologies, the concentration of PAI-1 seems to be associated with the histological cell types of NSCLC. We found the highest values of PAI-1 in large cell carcinoma > SCC, AC > carcinoid and lowest values in metastases of primary tumours of other organs. Only PAI-1 was significantly increased in poorly-differentiated cells (G3) compared to well- and moderately- differentiated cells (G1/G2). PAI-1 significantly correlated with cath B(AT) and cath B(A7.5) with uPAR (ADI), uPAR (HD13), uPAR (IIIF10) with uPA, and only weakly with TF, but not with cath B(C) and cath L(C). Significant correlations with overall survival in the total population of NSCLC patients were observed in univariate analysis for cath B(AT), cath B(C), PAI-1, uPAR (ADI), uPAR (HD13), and uPAR (IIIF10). Cath L(C) was not significantly associated with poor prognosis. Regarding the histological tumour type, only in patients with squamous cell carcinomas did cath B(A7.5) and PAI-1 remain significant prognostic factors. In multivariate survival analysis only two proteolytic factors, PAI-1 and uPAR (III101F), stayed significant. In conclusion, among 10 biological parameters evaluated within the same cohort of patients, only PAI-1, uPAR (ADI), uPAR (HD13), uPAR (IIIF10), cath B(AT) and cath B(C) are prognostic factors for overall survival of NSCLC patients. Moreover, PAI-1 and uPAR (IIIF10) add independent prognostic information with regard to established clinical and histomorphological factors in NSCLC.

Evolution of the brain tumour spheroid model: transcending current model limitations.

Tumour recurrence and the high mortality and morbidity associated with malignant brain tumours may be attributed to the failure of current therapeutic modalities (surgery, radiation and chemotherapy) to control the invasion of malignant brain tumour cells into healthy brain tissue. Several in vitro and in vivo models have been developed and used to study brain tumour invasion and cell motility. Here, we review some of the traditional in vitro models of brain tumour invasion and the latest adaptations to the widely used spheroid model. Several research groups studying the mechanisms mediating brain tumour invasion have made important contributions to the field by improving in vitro models of tumour migration and invasion. Sharing these advances will hopefully accelerate experimental discovery and the development of novel anti-invasion brain tumour therapies.

Proteases in brain tumour progression.

Local invasion of tumour cells is characteristic of brain tumour progression. It is associated with increased motility and a potential to hydrolyse macromolecular components of the extracellular matrix. The peptidases that have been most investigated, and are induced during this process, are reviewed: the plasminogen activators (PAs), matrix metalloproteinases (MMPs) and lysosomal cysteine peptidases called cathepsins (Cats). Increased levels of urokinase-type PA (uPA) are observed mainly at the invasive margins of a tumour, whereas the data on the expression of tissue-type PA (tPA) are still controversial. It has been shown that the endogenous inhibitor of PAs, PAI-1, is localised in both tumour and tumour-associated endothelial cells. Among MMPs, the expression of the gelatinases, MMP2 and MMP9, strongly correlates with glioma progression. Membrane bound MT-MMPs, in particular MT1- and MT2-MMP, seem to play a major role in activating MMP-2. Several members of the ADAMTS family have also been detected in brain tumours, the most relevant being ADAMTS4, due to its cleavage of CNS specific proteins. Lysosomal cathepsin B is highly expressed in malignant glial cells and in endothelial cells of vascularised glioblastomas and is a predictor of a shorter survival. In addition to invasion, cathepsin L may play a role in decreased susceptibility of anaplastic glioma cells to apoptosis. Finally, cathepsin B was proposed as a marker for malignancy in the more aggressive type of meningiomas. Each of these peptidases may act alone, or in concert with the others, to support malignant behaviour of brain tumour cells; the development of new inhibitors of invasion, therefore, should contribute to the control of local spread of a tumour.

DNA damage and metallothionein synthesis in human hepatoma cells (HepG2) exposed to cadmium.

Cadmium is an important heavy metal environmental toxicant, which is classified as a human carcinogen. The comet assay was used to evaluate the levels of DNA damage in a metabolically competent HepG2 cell line after treatment with low, non-cytotoxic and physiologically relevant concentrations of cadmium, alone and in combination with the dietary mutagen 2-amino-3-methyl-imidazo[4,5-f]quinoline (IQ) and with the environmental mutagen benzo[a]pyrene (B(a)P). After exposure of the cells to 10, 100 and 1000 nM CdCl(2), a dose- and time-dependent increase of DNA damage was detected. Maximal damage was found after 12 h of treatment, but declined with further incubation with CdCl(2). The increased synthesis of metallothioneins on exposure to CdCl(2) up to 12 h suggests that they are responsible for the adaptation of HepG2 cells to the DNA damaging effects of CdCl(2). Co-treatment of the cells with CdCl(2) (10-1000 nM) and IQ (300 microM) induced a dose-dependent increase of DNA damage compared to cells treated with IQ alone. Co-genotoxic activity was also observed by increased formation of micronuclei in cells exposed to IQ and 1000 nM CdCl(2); at this concentration, CdCl(2) alone also induced micronuclei in HepG2 cells. Our results support the hypothesis that direct and indirect mechanisms are involved in cadmium-induced DNA damage.

Invasion of ras-transformed breast epithelial cells depends on the proteolytic activity of cysteine and aspartic proteinases.

It has been suggested that the lysosomal proteinases cathepsin B, L and D participate in tumour invasion and metastasis. Whereas for cathepsins B and L the role of active enzyme in invasion processes has been confirmed, cathepsin D was suggested to support tumour progression via its pro-peptide, rather than by its proteolytic activity. In this study we have compared the presence of active cathepsins B, L and D in ras-transformed human breast epithelial cells (MCF-10A neoT) with their ability to invade matrigel. In this cell line high expression of all three cathepsins was detected by immunofluorescence microscopy. The effect of proteolytic activity on cell invasion was studied by adding various natural and synthetic cysteine and aspartic proteinase inhibitors. The most effective compound was chicken cystatin, a general natural inhibitor of cysteine proteinases, (82.8+/-1.6% inhibition of cell invasion), followed by the synthetic inhibitor trans-epoxysuccinyl-L-leucylamido-(4-guanidino) butane (E-64). CLIK-148, a specific inhibitor of cathepsin L, showed a lower effect than chicken cystatin and E-64. Pepstatin A weakly inhibited invasion, whereas the same molar concentrations of squash aspartic proteinase (SQAPI)-like inhibitor, isolated from squash Cucurbita pepo, showed significant inhibition (65.7+/-1.8%). We conclude that both cysteine and aspartic proteinase activities are needed for invasion by MCF-10A neoT cells in vitro.

Cathepsins B and L are markers for clinically invasive types of meningiomas.

OBJECTIVE: Meningiomas are benign neoplasms that derive from coverings of the brain. Approximately 10% of benign tumors progress into atypical, malignant tumors, thus constituting a subset of histopathologically benign tumors that are clinically invasive. The aim of this study was to evaluate cathepsins B and L and their inhibitors as new prognostic factors that could distinguish malignant from benign forms of meningiomas. METHODS: Using immunohistochemical analysis and specific monoclonal antibodies, we evaluated the levels of cathepsins B and L and the levels of the endogenous cysteine proteinase inhibitors stefin A and cystatin C in 88 meningiomas. Immunohistochemical scores were determined as the sum of the frequency (0-3) and intensity (0-3) of immunolabeling of the tumor cells. RESULTS: Of the 88 tumors studied, 67 were benign meningiomas and 21 were atypical meningiomas. Among the benign group, nine tumors had certain features of malignancy. These tumors were classified as border benign meningiomas, and the rest were classified as clear benign meningiomas. A high immunohistochemical score (4-6) for cathepsin B was more frequent in atypical tumors than in clear benign tumors (P < 0.001). Compared with clear benign tumors, higher cathepsin B immunohistochemical scores were found in atypical tumors (P < 0.001) and border benign tumors (P < 0.03). No statistical difference in immunohistochemical staining of cathepsin B was found between atypical meningiomas and border benign meningiomas. Higher expression of cathepsin L was found in atypical tumors as compared with clear benign tumors (P < 0.03), but it was not observed in border benign as compared with clear benign meningiomas. No immunostaining for stefin A and cystatin C was detected in any of the tumors. CONCLUSION: We show that the levels of cathepsin B and cathepsin L antigens are significantly higher in invasive types of benign meningioma. Specifically, cathepsin B may be used as a diagnostic marker to distinguish histomorphologically benign but invasive meningiomas from histomorphologically clear benign tumors.

Cysteine proteinases and their inhibitors in extracellular fluids: markers for diagnosis and prognosis in cancer.

Cathepsins B, H and L have been shown to participate in processes of tumor growth, vascularization, invasion and metastasis. Their levels in tumor tissue extracts can provide useful clinical information to predict disease-free and overall survival in breast, lung, colorectal, brain and head and neck cancer patients. Recently we have found that both cysteine cathepsins and their endogenous protein inhibitors stefins and cystatin C can also predict prognosis when measured extracellularly. In melanoma and colorectal cancer patients high serum levels of cathepsins B and H correlated with shorter survival. Similarly, increased extracellular levels of stefins A and B and cystatin C correlated significantly with high risk of adverse outcome in cancer patients. However, the cathepsin B/cystatin C complex was found to be less abundant in sera of patients with malignant tumors than in those with benign diseases or in healthy controls, suggesting an imbalance between the enzyme and its inhibitor in cancer patients.

Cysteine proteinase cathepsin H in tumours and sera of lung cancer patients: relation to prognosis and cigarette smoking.

In order to evaluate the role of cysteine peptidase cathepsin H (Cath H) in human lung cancer its protein levels were determined in 148 pairs of lung tumour tissue and adjacent non-tumourous lung parenchyma using the enzyme-linked immunosorbent assay technique. Additionally, Cath H levels were determined in sera of 171 patients with malignant tumours, 34 patients with benign lung diseases and 47 healthy controls. The median level of Cath H in tumour tissue was 0.64 times that in the corresponding lung parenchyma. Relating tumour levels with histological type we found higher Cath H levels in small-cell and adenocarcinomas and lower levels in squamous cell carcinoma, large-cell carcinoma and secondary tumours. A significant difference in Cath H level between lung tumour tissue and non-tumourous lung parenchyma was associated with the group of cigarette smokers (156 vs 263 ng mg(-1) protein, P < 0.001). For this group of patients Cath H tumour levels correlated with the survival rate, while for the entire patient population this was not the case. Smokers with high tumour levels of Cath H experienced poor survival. Cath H was significantly higher in sera of patients with malignant and benign lung diseases than in control sera (P < 0.001). The increase was significant for all histological types, being the highest in small-cell and squamous cell carcinomas. Our study reveals that in lung tumours there is different behaviour of Cath H compared with other cysteine peptidases, e.g. cathepsin B and cathepsin L. Variations between tissue and serum levels of Cath H indicate either reduced expression or enhanced secretion of this enzyme in lung tumours.

Cathepsin B and its inhibitor stefin A in brain tumors.

Cysteine protease cathepsin B (CatB) and its endogenous inhibitor stefin A (StA) play an important role in tumor progression. Increase of CatB expression and lower levels of its inhibitors were associated with tumor malignancy in brain tumors. In this study of 100 patients, CatB was localized by immunostaining to both, tumor and endothelial cells of primary brain tissue. Significant correlation with poor prognosis was found by univariate Cox's regression model. Intense overall immunostaining and immunostaining in endothelial cells alone were prognostic for survival (p=0.003 in both). When comparing CatB expression at mRNA level, we found considerable differences between center and periphery of a tumor as well as between different tumor samples. StA mRNA was only detected in benign, but not in malignant tissues. We suggest that screening of cysteine-protease genes expression can be applied in clinical prognosis of brain tumors.

Cells producing cathepsins D, B, and L in human breast carcinoma and their association with prognosis.

Lysosomal proteinases, cathepsins D, B, and L have been associated with malignant tumor progression and with prognosis in various human carcinomas. In the current study, the immunohistochemical localization of cathepsins in tumor cells was correlated with cathepsin protein concentration in breast carcinoma cytosols from 77 patients. Significant correlation was found for cathepsin D (P < .041) and borderline correlation for cathepsin B (P < .055) but not for cathepsin L. We hypothesize that the poor correlation of cysteine cathepsins was attributable to the fact that they were present not only in malignant epithelial cells, but also in infiltrating macrophages and stromal fibroblasts. In addition, tumor-surrounding myoepithelial cells (42% of tumors) and myofibroblasts (26% of tumors) as well as endothelial cells of neovasculature (10% of tumors) all stained specifically for cathepsin B. Two thirds of tumors co-expressed cathepsins B and L in tumor cells, whereas only 17% of tumors co-expressed all 3 cathepsins. Intense immunostaining for cathepsin D of tumor cells was observed in tumors at high TNM stage and tumors having positive lymph nodes. The expression of cathepsin B was independent of established prognostic factors, whereas intense cathepsin L staining in tumor cells was associated with high histological grade. With respect to prognosis of patient survival, only tumor cell-associated cathepsin D (P = .042) and myoepithelial cell-associated cathepsin B (P = .061) showed borderline significance. Cathepsins B and L immunostaining in tumor cells was not prognostic. In contrast, cytosolic levels of cathepsin B correlated with higher rate of relapse. Taken together, these results show the diversity in the cellular distribution of cathepsins in human breast carcinoma, presumably reflecting specific regulation and function of each of the cathepsins during tumor progression.

Cathepsin B, a prognostic indicator in lymph node-negative breast carcinoma patients: comparison with cathepsin D, cathepsin L, and other clinical indicators.

New prognosticators are needed for breast cancer patients after the initial surgical treatment to make therapeutic decisions that ultimately will affect their DFS. These consist of specific proteolytic enzymes including lysosomal endopeptidases. In this study, the activity and protein concentrations of cathepsins (Cats) D, B, and L were measured in 282 invasive breast tumor cytosols. These potential biological prognostic indicators were compared with other histopathological parameters, such as tumor size, lymph node involvement, tumor-node-metastasis stage, histological grade, DNA analysis, and steroid receptors. CatD protein concentration correlated with lymph node involvement. CatB and CatL levels correlated significantly with Scarf-Bloom-Richardson histological grade and were also higher in estrogen-negative tumors, and CatB was higher in larger tumors. As prognostic markers, CatB concentration was significant for increased risk for recurrence in the entire patient population and specifically also in lymph node-negative patients as follows: high CatB concentration (above 371 micrograms/g) in tumor cytosols was significant (P < 0.00) for high risk of recurrence but was of only borderline prognostic significance (P < 0.06) for overall survival of all patients. In lymph node-negative patients, CatB (above 240 micrograms/g, P < 0.003) was highly significant for recurrence-free survival, followed by CatL (above 20 micrograms/g, P < 0.049) and CatD (above 45 nmol/g, P < 0.044) concentrations. For overall survival of node-negative patients, only CatB was a significant (P < 0.014) prognosticator. We conclude that CatB is useful as a prognostic indicator in lymph node-negative patients. This suggests that selective adjuvant therapy should be applied in this lower risk group of patients when high levels of CatB are determined.

Cathepsin B in infiltrated lymph nodes is of prognostic significance for patients with nonsmall cell lung carcinoma.

BACKGROUND: Tumor cells require specific proteolytic enzymes for invasion and metastasis, including lysosomal peptidases--cathepsins. Cathepsin B is a lysosomal cysteine peptidase, which appears to play a major role in invasion and metastasis of human tumors. In this study, the authors focused on the possible role of cathepsin B in lymphogenic metastasis by investigating the enzyme localization and its activity in lung tumors and corresponding tumor-infiltrated lymph nodes. METHODS: Cathepsin B activity was determined in lung tumors, lung parenchyma, and tumor cell-infiltrated and noninfiltrated regional lymph nodes of the same patient. The authors investigated 35 cancer patients suffering from nonsmall cell lung carcinoma. Cathepsin B throughout activity was measured by cleavage of the fluorogenic substrate Z-Arg-Arg-AMC at pH 6.0. RESULTS: The median specific cathepsin B activity was highest in tumors, followed by the infiltrated lymph nodes, noninfiltrated lymph nodes, and lung parenchyma. The authors showed a significant 1.8-fold increase in cathepsin B activity in tumor-infiltrated lymph nodes compared with noninfiltrated regional lymph nodes and a 4.5-fold increase in lung tumor tissue compared with lung parenchyma. High cathepsin B activity, both in tumors and tumor cell-infiltrated lymph nodes, indicated poor prognosis for overall survival. Immunohistochemical analysis showed the presence of cathepsin B in histiocytes and tumor cells but not in lymphocytes of lymph node tissue. CONCLUSIONS: The authors' findings on higher cathepsin B levels in tumor cell-infiltrated lymph nodes show that increased level of cathepsin B activity is characteristic of the invasive tumor cell phenotype. This corroborates the hypothesis, that tumor cell associated cathepsin B may play a role in lymphogenic metastasis. The authors' results support the use of lymph node associated cathepsin B as a prognostic factor for survival of patients with lung carcinoma.

Immunochemical analysis of cathepsin B in lung tumours: an independent prognostic factor for squamous cell carcinoma patients.

In order to evaluate the possible role of the proteolytic enzyme cathepsin B (cath B) in human non-small cell lung cancer (NSCLC) we examined cath B concentrations (cath B(C)) and activities (cath B(A)) in homogenates of 127 pairs of lung tumour tissues and corresponding non-tumourous lung parenchyma. Total cath B activity (cath B(AT)) and enzymatic activity of the fraction of cath B, which is stable and active at pH 7.5 (cath B(A7.5)) were determined by a fluorogenic assay using synthetic substrate Z-Arg-Arg-AMC. The immunostaining pattern of cath B was determined in 239 lung tumour tissue sections, showing the presence of the enzyme in tumour cells (cath B(T-I)) and in tumour-associated histiocytes (cath B(H-I)). The median levels of cath B(AT), cath B(A7.5) and cath B(C) were 5.6-, 3.2- and 9.1-fold higher (P < 0.001), respectively, in tumour tissue than in non-tumourous lung parenchyma. Out of 131 tissue sections from patients with squamous cell carcinoma (SCC), 59.5% immunostained positively for cath B, while among the 108 adenocarcinoma (AC) patients 48.2% of tumours showed a positive reaction. There was a strong relationship between the levels of cath B(AT), cath B(A7.5), cath B(C) and cath B(T-I) in the primary tumours and the presence of lymph node metastases. Significant correlation with overall survival was observed for cath B(T-I) and cath B(A7.5) (P < 0.01 and P < 0.05, respectively) in patients suffering from SCC. In these patients positive cath B in tumour cells (cath B(T-I)) and negative cath B in histiocytes (cath B(H-I)) indicated significantly shorter survival rate compared with patients with negative cath B(T-I) and positive cath B(H-I) (P < 0.0001). In contrast, in AC patients, both, positive cath B(T-I) and positive cath B(H-I), indicated poor survival probability (P < 0.014). From these results we conclude that the proteolytic enzyme cath B is an independent prognostic factor for overall survival of patients suffering from SCC of the lung.