[Type I and IV collagenases and their endogenous regulators in immortalized and transformed fibroblasts]. / Kollagenazy I i IV tipov i ikh éndogennye reguliatory v immortalizirovannykh i transformirovannykh fibroblastakh.

To elucidate the role of matrix metalloproteinases (MMP) in carcinogenesis, the expression of collagenases of types I (MMP-I) and IV (MMP-2 and MMP-9) as well as the behaviour of urokinase-like plasminogen activator (uPA) and of tissue MMP inhibitors (TIMP) in immortalized (IF) and transformed (TF) fibroblasts were investigated. The study was carried out using embryo rat fibroblasts, sequentially immortalized with the LT gene of human papilloma virus and transformed with the E7 gene of human papilloma virus (HPV-16). As control was used the primary fibroblast (PF) culture of Fisher rats. In IF, the collagenase activity was at the same level as it was in PF. The activity of uPA in IF was increased by 2-2.5-fold; the titrated amount of free endogenous inhibitors in IF and PF was at essentially the same level while being markedly higher than in TF. At the stage of fibroblast transformation with the E7 gene of HPV-16, there was seen an increase of Type IV collagenases and a decrease of Type I collagenase, both these indices being most pronounced in the cells with most developed tumorigenic properties. In TF there occurred a decrease of free endogenous MMP inhibitors relative to the enzyme activity and, at the same time, a decrease in uAF activity, indicating the changes occurring in the enzyme/inhibitor/activator ratio and hence the enhancement of the destructive potential of the cells (in this case, at the cost of Type IV collagenase activity).

[Expression of cathepsins D and L during neoplastic transformation of fibroblasts]. / Issledovanie ékspressii katepsinov D i L v protsesse onkogennoi transformatsii fibroblastov.

Study of the expression of the aspartyl cathepsin D-like and cysteine cathepsin L-like proteinases was carried out on a model system of rat embryo fibroblasts. The model system employed makes it possible to distinguish two discrete successive stages of transformation in vitro: immortalization and tumorigenic transformation. The dynamics of expression and subcellular distribution of proteinases throughout the transformation process was followed. It was shown that in immortalized and transformed cells the activities of the aspartyl and cysteine proteinases were expressed to a variable degree and the expression was dependent on the time of cell cultivation. The increase in both the aspartyl cathepsin D-like proteinase and cysteine cathepsin L- and B-like proteinase activities was correlated with the stage of fibroblast transformation. At all stages studied of transformation, the major part of cathepsin L-like proteinase activity was localized within the cell, while among secreted proteinases the cathepsin D-like proteinase was apparently predominant. It was found that the secreted cathepsin D-like proteinase in all cell cultures studied was complexed with the inhibitor.

[Interaction of collagenases with certain peptide substrates and inhibitors]. / Vzaimodeistvie kollagenaz s nekotorymi peptidnymi substratami i ingibitorami.

Interactions of collagenases I and II (clostridiopeptidases) from Clostridium histolyticum with hexapeptide substrates in which some L-proline residues are replaced by their D-analogues, as well as with the tripeptide chloromethyl ketone Z-Gly-Pro-Gly-CH2Cl were studied. A role of stereochemistry of the amino acid residues in the substrate was established and differences between the collagenases, with regard to their specific requirements to substrates, were revealed. The tripeptide chloromethyl ketone is shown to be a specific collagenase inhibitor modifying at the substrate-binding site in the active centre of these enzymes, most likely lysine residues.

[Study on the effect of some group-specific agents on clostridiopeptidase]. / Izuchenie deistviia nekotorykh gruppospetsificheskikh agentov na klostridiopeptidazu.

The interaction of clostridiopeptidase of Clostridium histolyticum with EDC, TNM and MA, the specific reagents for COOH-groups, tyrosine and lysine residues was studied. It was shown that at pH 6.0 EDC inactivates the enzyme. The inactivation process follows the pseudo-first order kinetics and is described by a second order rate constant equal to 1 M-1 min-1. The synthetic substrate does not prevent, in practical terms, the enzyme inactivation by EDC. At pH 8.0 TNM modifies about 19 tyrosine residues in the clostridiopeptidase molecule which is accompanied by marked inhibition of the enzyme activity (down to 70-90%). In this case, the inactivation process is not described by simple pseudo-first order kinetics but is characterized by two steps (fast and slow) with second order rate constants of approximately 14 and 3.5 M-1 min-1, respectively. The synthetic substrate partly prevents the inactivation of the enzyme by TNM and protects 11 tyrosine residues. The MA-induced incorporation of 13 +/- 3 maleyl groups into the clostridiopeptidase molecule in partially prevented by the synthetic substrate with protects the enzyme against inactivation. The data obtained suggest that lysine residues are seemingly included into the active center of clostridiopeptidase, whereas tyrosine residues provide for the maintenance of active conformation of the enzyme.

[Isolation and properties of 3 Clostridium histolyticum collagenases]. / Vydelenie i svoistva trekh kollagenaz Clostridium histolyticum.

The collagenases (I, II and III) have been obtained in a highly purified state from fresh cultural medium of Clostridium histolyticum. The collagenases were similar in their properties to clostridiopeptidase A. The three enzymes differed in their molecular weights, isoelectric points and in some chemical properties. Collagenase II exhibited the most potent hydrolytic activity. Its collagenolytic activity was two-fold higher and the peptidase activity was twenty-fold higher as compared with that of collagenase I. All the three enzymes were inactive towards azocasein and were inhibited by EDTA and cysteine.