Teresa Banaś

Oxidative alterations induced in vitro by the photodynamic reaction in doxorubicin-sensitive (LoVo) and -resistant (LoVoDX) colon adenocarcinoma cells

In photodynamic therapy (PDT) a tumor-selective photosensitizer is administered and then activated by exposure to a light source of appropriate wavelength. Multidrug resistance (MDR) is largely caused by the drug efflux from the tumor cell by means of P-glycoprotein, resulting in reduced efficacy of the anticancer therapy. This study deals with photodynamic therapy with Photofrin® (Ph) on colon cancer cell lines (doxorubicin-sensitive and -resistant). The cells were treated with 15 and 30 μg/mL Ph and then irradiated by a light dose of 3 or 6 J/cm2 (632.8 nm). After irradiation the cells were incubated for 0, 3 or 18 h. Crucial factors of oxidative stress (thiobarbituric acid reactive substances [TBARS], protein damage, thiazolyl blue tetrazolium bromide [MTT] assay), changes in cytosolic superoxide dismutase (SOD1) activity after photodynamic reaction (PDR), and the intracellular accumulation of photosensitizers in the cells were examined. Moreover, the expressions of glutathione S-transferase (GST)-pi, a marker protein for photochemical toxicity, and secretory phospholipase A2, a prognostic and diagnostic marker for colon cancers, were determined. After PDR, increases in SOD1 activity and the level of TBARS were observed in both cell lines. The level of protein-associated –SH groups decreased after PDR. Both cell lines demonstrated stronger GST-pi and PLA2 expression after PDR, especially after 18 h of incubation. The increasing level of reactive oxygen species following the oxidation of sulfhydryl cell groups and lipid peroxidation influence the activity of many transporters and enzymes. The changes in SOD1 activity show that photodynamic action generates oxidative stress in treated cells. Our study presents that PDR caused oxidative alterations in both examined colon adenocarcinoma cell lines. However, the MDR cells reacted more slowly and all oxidative changes occurred in the delay.

Enolase-like protein present on the outer membrane of Pseudomonas aeruginosa binds plasminogen.

Pseudomonas aeruginosa is one of the pathogenic bacteria which utilize binding of the host plasminogen (Plg) to promote their invasion throughout the host tissues. In the present study, we confirmed that P. aeruginosa exhibits binding affinity for human plasminogen. Furthermore, we showed that the protein detected on the cell wall of P. aeruginosa and binding human plasminogen is an enolase-like protein. The hypothesis that alpha-enolase, a cytoplasmatic glycolytic enzyme, resides also on the cell surface of the bacterium was supported by electron microscopy analysis. The plasminogen-binding activity of bacterial cell wall outer membrane enolase-like protein was examined by immunoblotting assay.

Fluorescence studies on glyceraldehyde-3-phosphate dehydrogenase from bovine heart muscle.

Abstract Glyceraldehyde-3-phosphate Dehydrogenase, ATP, Flu orescence Glyceraldehyde-3-phosphate dehydrogenase is a glycolytic enzyme that catalyses conversion of glyceralde-hyde-3-phosphate to 1,3-diphosphoglycerate. ATP has been found to have an inhibitory effect on this enzyme. To establish the interaction between the enzyme and ATP, a fluorescence technique was used. Fluorescence quenching in the presence of ATP suggests cooperative binding of ATP to the enzyme (the Hill obtained coefficient equals 2.78). The interaction between glyceralde-hyde-3-phosphate dehydrogenase and ATP may control not only glycolysis but other activities of this enzyme, such as binding to the cytoskeleton.

Inhibition of Angiotensin - Converting Enzyme by a Synthetic Peptide Fragment of Glyceraldehyde-3-phosphate Dehydrogenase

Abstract A novel inhibitor of angiotensin - converting enzyme (ACE) identical to a sequence part of human muscle glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was chemically synthesized. Amino acid sequence was as follows Pro - Glu - Asn - Ile - Lys - Trp - Gly - Asp. This peptide inhibited rabbit lung ACE with a K1 value of 1.6 μм. The inhibitor of ACE acts in a non-competitive manner. The amino acid sequence of the new inhibitor was com- pared of GAPDH from other sources.