Kristina Gopcevic

Activity of MMP-2 and MMP-9 in sera of breast cancer patients

Gelatinase A (MMP-2) and gelatinase B (MMP-9) are proteolytic enzymes involved in the process of tumor invasion, and they are considered as possible tumor markers in breast cancer patients. In this study, we examined serum activity of proMMP-2 and proMMP-9 in relation to TNM stage, tumor size, lymph node involvement, grade of differentiation of tumors, as well as steroid and Her2/neu receptor status in breast cancer patients. The activity of gelatinase in the sera of 52 patients was analyzed by SDS-PAGE zymography. The activity of proMMP-2 and proMMP-9 significantly increased with each advancing clinical stage of disease (p=0.02-0.0009) and compared to controls (p=0.015 to p<0.01). We found a positive correlation between the activity of proMMP-2 and proMMP-9 and tumor size (p=0.007; p=0.05). Patients with lymph node-positive cancer have higher proMMP-2 and proMMP-9 activity than those with node-negative cancer. ProMMP-2 and proMMP-9 activity is not associated with the expression of Her2/neu receptors, but patients with Her2/neu overexpression (3+) showed increased proMMP-2 activity. Steroid receptor score is not associated with enhanced gelatinase activity. The relationship between the increase in proMMP-2 and proMMP-9 activity in serum and tumor size and lymph node status suggests the usefulness of these enzymes as staging markers of breast cancer patients.

Values of MMP-2 and MMP-9 in Tumor Tissue of Basal-Like Breast Cancer Patients

Gelatinase A (MMP-2) and gelatinase B (MMP-9) are proteolytic enzymes involved in process of tumor invasion, and they are considered as possible tumor markers in breast cancer patients. In this study, we measured activity of latent and active form of MMP-2 and MMP-9 in tumor and adjacent tissue of 60 breast cancer patients by SDS-PAGE zymography. The activity of both form of gelatinases significantly increased with each advancing clinical stage of disease. ProMMP-9 and aMMP-9 activity in tumor tissue shows a positive association with tumor size. Patients with lymph node involvement have higher proMMP-2, aMMP-2 and aMMP-9 activity than node negative patients. Steroid receptor-negative tumors had enhanced aMMP-2 and aMMP-9 activity. Patients with basal-like cancers had higher proMMP-2 tumor activity and aMMP-2 adjacent tissue activity compared to patients with luminal A tumors. Patients with negative hormone receptors are associated with increased activity of both form of gelatinases in adjacent tissue. Reported increased activity of MMP-2 in tumor and adjacent tissue of basal-like tumors implicates that MMP-2 might have a role in aggressive biology of basal-like cancers. Additional investigations regarding molecular pathways in adjacent tissue could give better insight into aggressive nature of basal-like carcinomas.

Lactate dehydrogenase, Catalase, and Superoxide dismutase in Tumor Tissue of Breast Cancer Patients in Respect to Mammographic Findings

Lactate dehydrogenase (LDH), marker of anaerobic metabolism, is associated with highly invasive and metastatic breast cancer. Novel studies show that increased anaerobic metabolism (LDH), as well as activity of antioxidative enzymes (superoxide dismutase (SOD) and catalase (CAT)), is correlated with higher mammographic density, as known predictor of breast cancer risk. In this study, we measured LDH, MDH, and SOD activity in tumor and adjacent tissues of breast cancer patients by spectrophotometric assay. Mammograms were evaluated according to the American College of Radiology Breast Imaging Reporting and Data system. Mammographically dense breast tissue is associated with higher activity of LDH in tumor tissue of breast cancer patients. Moreover, patients with masses have significantly higher activity of LDH compared to patients with focal asymmetries or architectural distortion. Patients with spiculated mass margin had higher activity of LDH compared to patients with focal asymmetries or architectural distortion. Activity of LDH in patients significantly increases, while activity of CAT significantly decreases with the increase of BIRADS category. These results suggest that the association of activity of LDH and CAT in tumor tissue with mammographic characteristics could help in defining aggressive breast cancers.

Activity of Superoxide Dismutase, Catalase, Glutathione Peroxidase, and Glutathione Reductase in Different Stages of Colorectal Carcinoma

BackgroundReactive oxygen species are involved in the pathogenesis of colorectal carcinoma. Clarification of oxidative/antioxidant specificities of different stages of colorectal carcinoma is of special importance.AimTo determine oxidative/antioxidant status in plasma of patients with different stages of colorectal carcinoma using malondialdehyde concentration, superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase activities and distribution of superoxide dismutase isoforms.MethodsLipid peroxidation and antioxidant enzymes activity were estimated using spectrophotometric methods. Reverse zymography was applied for characterization of superoxide dismutase isoforms.ResultsLipid peroxidation is increased in all groups compared to the control, but without differences between different stages of colorectal carcinoma. Total superoxide dismutase activity is lower in all colorectal carcinoma groups than in control, and there is a significant increase in tumor stage IV when compared with tumor stage II. Manganese superoxide dismutase isoform is dominant in all groups and its relative activities are significantly higher than activities of a copper/zinc isoform. Total peroxidase potential reflected in catalase and glutathione peroxidase activity is increased when compared to the control, but without any significant differences between colorectal carcinoma groups. Glutathione reductase activity is lower in all colorectal carcinoma groups than in control, and a significant decrease in glutathione reductase activity was obtained between patients in tumor stage II and III compared to tumor stage IV.ConclusionsColorectal carcinoma is characterized by increased oxidative stress and antioxidant disbalance. Progression of disease is followed by an increase in redox disbalance.

Enzymatic characterization of 30 kDa lipase from Pseudomonas aeruginosa ATCC 27853

An extracellular lipase from Pseudomonas aeruginosa ATCC 27853 has been purified and its enzymatic characteristics were determined. According to SDS‐PAGE and gel filtration molecular mass estimated to be 30 kDa, what classified the lipase in group I.1. Although 14 lipases from P. aeruginosa with similar molecular mass are referred to date, their basic enzymatic properties have not been reported yet. To address the gap we found: the optimal temperature and pH in water solution being 50 °C and 9.3, respectively; the lipase was inhibited with Hg2+ ions and sodium dodecylsulphate (SDS), while non‐ionic detergent Triton X‐100 activated the enzyme; the lipase hydrolyzed more rapidly middle chain triglycerides and it was not regiospecific; the lipase demonstrated naturally occurring stability in different organic solvents with concentrations ranging from 30 to 70%, including good thermal stability in 30% organic solvent solution. Even though strain P. aeruginosa ATCC 27853 was not isolated from extreme environment it showed activity in organic solvent suggesting that this lipase is suitable for variety of applications, including reactions in water restricted medium and bioremediation of contaminations by organic solvents. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

HER2-positive breast cancer patients: correlation between mammographic and pathological findings.

Human epidermal growth factor receptor 2 (HER2)-positive breast cancers represent a highly aggressive breast cancer subtype and are associated with a worse prognosis. This study was designed to investigate the mammography finding of HER2-positive breast cancer and to compare the results with the characteristics of HER2-negative breast cancer patients. From January 2010 to October 2011, mammography findings of 65 patients with pathologically confirmed HER2-positive breast cancers (n = 22) or HER2-negative breast cancers (n = 43) were retrospectively reviewed. The authors also reviewed pathological reports for information on the histological type and differentiation grade. Among the two types of breast cancer patients, estrogen receptor-negative/PR-negative/HER2-positive breast cancer patients most commonly had associated calcifications (18 of 22) on mammography. On mammography, cases with a cluster of calcifications usually were presented as pleomorphic calcifications (12 of 20) and branching calcifications (4 of 20). Patients with HER2-positive breast cancers showed a histological grade II. HER2-positive breast cancer patients usually had ductal invasive carcinoma (17 of 22). Moreover, postmenopausal patients showed a significantly higher frequency of HER2-positive tumours. Our results suggest that the imaging findings might be useful in diagnosing HER2-positive breast cancer patients.

Cadmium specific proteomic responses of a highly resistant Pseudomonas aeruginosa san ai

Pseudomonas aeruginosa san ai is a promising candidate for bioremediation of cadmium pollution, as it resists a high concentration of up to 7.2 mM of cadmium. Leaving biomass of P. aeruginosa san ai exposed to cadmium has a large biosorption potential, implying its capacity to extract heavy metal from contaminated medium. In the present study, we investigated tolerance and accumulation of cadmium on protein level by shotgun proteomics approach based on liquid chromatography and tandem mass spectrometry coupled with bioinformatics to identify proteins. Size exclusion chromatography was used for protein prefractionation to preserve native forms of metalloproteins and protein complexes. Using this approach a total of 60 proteins were observed as up-regulated in cadmium-amended culture. Almost a third of the total numbers of up-regulated were metalloproteins. Particularly interesting are denitrification proteins which are over expressed but not active, suggesting their protective role in conditions of heavy metal exposure. P. aeruginosa san ai developed a complex mechanism to adapt to cadmium, based on: extracellular biosorption, bioaccumulation, the formation of biofilm, controlled siderophore production, enhanced respiration and modified protein profile. An increased abundance of proteins involved in: cell energy metabolism, including denitrification proteins; amino acid metabolism; cell motility and posttranslational modifications, primarily based on thiol-disulfide exchange, were observed. Enhanced oxygen consumption of biomass in cadmium-amended culture versus control was found. Our results signify that P. aeruginosa san ai is naturally well equipped to overcome and survive high doses of cadmium and, as such, has a great potential for application in bioremediation of cadmium polluted sites.

Matrix metalloproteinases and membrane damage markers in sera of patients with acute myocardial infarction

Coronary artery disease is a multifunctional disease and represents one of the leading causes of death worldwide. Oxidative stress appears as an etiological factor for myocardial damage during acute myocardial infarction. Some data suggest that acute coronary syndromes may also be influenced by matrix metalloproteinases through degradation of the fibrous cap of vulnerable atherosclerotic lesions. It has been indicated that gelatinases A and B play a key role in acute myocardial infarction and deoxyribonuclease I has been postulated to be a novel early phase marker of disease. The aim was to study activity of gelatinases A and B in acute myocardial infarction and its association with some membrane damage markers. Seventy-five patients with disease and seventy-five healthy controls were enrolled. Activities of lactate dehydrogenase, malate dehydrogenase, and deoxyribonuclease I were estimated using standard spectrophotometric assay and isoforms of lactate and malate dehydrogenases were determined using direct zymography. Activity of dehydrogenases was significantly higher in patients, while deoxyribonuclease I was lower. Isoform 2 of lactate dehydrogenase was significantly higher in the patient group. Gelatinases A and B were detected only in patients group. The results suggest determination of serum malate dehydrogenase activity to be used as an additional parameter for acute myocardial infarction diagnosis. Those findings suggest important role of gelatinases A and B as biomarkers of early stage of acute myocardial infarction together with membrane damage parameters.

The influence of Al3+ ion on porcine pepsin activity in vitro.

The in vitro effect of Al3+ ions in the concentration range 1.7·10− 6 M–8.7·10− 3 M on pepsin activity at pH 2, via kinetic parameters and its electrophoretic mobility was evaluated. Kinetic study demonstrated the existence of an activation effect of Al3+ at pH 2 on pepsin molecule. Kinetic analysis with respect to concentrations of haemoglobin showed that Al3+ ions increase the maximal velocity (Vmax) and kcat values rather than apparent affinity for substrate (KS) implying the non-competitive nature of activation which indicated that aluminium was a non-essential activator of partial non-competitive type. The values of the equilibrium constants KS and KmA for dissociation of corresponding complexes were evaluated as 0.904 ± 0.083 mM and 8.56 ± 0.51 μM, respectively. Dissociation constant KA, of activator from enzyme-activator complex calculated via kinetic and direct measurement of Al3+ binding data, as well as activation constant A50, the activator concentration that gives a rate equal to half at a saturating concentration of activator, were found to be 8.82 ± 0.90 μM, 8.39 ± 0.76 μM, and 8.05 ± 0.48 μM respectively. Native PAGE electrophoresis shows the decrease in electrophoretic mobility of pepsin and confirms modification of the electric charge and conformational changes of pepsin caused by bound Al3+ on the pepsin molecule. Al3+ induced conformational changes of pepsin were verified by UV-VIS and IR spectra. Moreover, the absence of conformational changes in the haemoglobin molecule in the presence of Al3+ ions confirms that the obtained activation is a consequence of conformational changes caused only in the pepsin molecule.

Papillary Thyroid Carcinoma: A Malignant Tumor with Increased Antioxidant Defense Capacity

Papillary thyroid carcinoma (PTC) is the commonest thyroid malignancy worldwide for which the radiation exposure is the most influential risk factor. The levels of oxidative stress in PTC are not well characterized on the tissue level. The objective of this study was to evaluate total oxidant status (TOS) and total antioxidant status (TAS) in PTC and benign goiter (BG) tissues and to examine their association with clinicopathological characteristics. Tumor and normal thyroid tissue samples were collected from 59 PTC patients, and goiter tissues were collected from 50 BG patients. TOS and TAS were quantified in the tissue homogenates by spectrophotometric assays. TOS values in tumor tissues did not differ significantly from normal and goiter tissues; however, PTC tissues have significantly higher TAS values than normal and goiter tissues. TOS values correlated with retrosternal growth in BG patients. The significant correlations were found between TOS and TAS values and thyroid function parameters. In 17 PTC patients with multiple tumor foci (multicentric phenotype), TAS values were significantly lower, compared to 42 patients with unicentric PTC. TAS and TOS are the most useful predictors of thyroid capsular invasion by PTC. The age, sex, body mass index, smoking, familial history of thyroid disease and nodule size did not influence TOS and TAS in PTC or BG patients. In conclusion, we show the profiles of TOS and TAS in PTC and BG tissues. Importantly, PTC tissues possess increased antioxidant capacity. The redox status influences the parameters of the thyroid function and tumors biological behavior.