[The role of extracellular chaperone Hsp70 in creating antitumor immunity in rat rhabdomyosarcoma RA-2 model].

Immunization of experimental animals with extract or membranes of rat rhabdomyosarcoma RA-2 in combination with pure Hsp70 did not offer any significant effect of protection from subsequent RA-2 cells-stimulated tumor growth. By contrast, immunization with preparations of pure Hsp70 led to a significant decrease in number and size of tumors as well as elevation of concentrations of antibodies against RA-2 cells. Also, enhanced blood levels of Hsp70 involved delayed tumor growth. In vitro tests Hsp70 incubation with RA-2 cells was followed by a 30-35% rise in cytotoxic lymphocytes levels. An ability of pure Hsp70 preparations to stimulate humoral and antitumor response was demonstrated. Hence, they may be used in developing vaccine formulas.

[The role of Hsp70 chaperone in the reaction of human leukemic cells to anticancer drugs]. / Rol' shaperona Hsp70 v reaktsii kletok leikemii cheloveka na protivoopukholevye preparaty.

Most of anti-tumor factors are designed to kill selectively cancer cells; in most cases this action is related to the ability of the above substances to induce apoptosis. One of potent anti-apoptotic mechanisms is based on Hsp70 protein. Since the level of this protein is often higher in malignant tumors than in normal tissues, the aim of this study was to establish whether the elevated Hsp70 content may influence the process of apoptosis induced by anti-tumor drugs in cancer cells population. The increase of intracellular content of Hsp70 in human leukemia U-937 cells was attained by a mild heat stress or by transfection of cells with the human hsp70 gene. The elevation of Hsp70 quantity, irrespective of the way it was performed, leads to the inhibition of apoptosis in cells treated with two substances, etoposide or adriamycin. The inhibition of apoptosis was accompanied with the reducing of the share of cells with fragmented nuclei and with the delay in caspase activation. It is suggested that in addition to the previously discovered targets, whose activity is suppressed by the Hsp70 chaperone, this protein can inhibit the activity of caspase-3 and -7; this delays the onset of apoptosis in part of a cancer cell population.

[Role of heat-shock proteins in cardioprotection of patients operated on for ischemic heart disease]. / Rol' belka teplovogo shoka v kardioprotektsii u bol'nykh, operirovannykh po povodu ishemicheskoi bolezni serdtsa.

Major stress protein HSP72 is known to participate in protecting cells and organisms against harmful factors including ischemia, trauma etc. Under study was the level of HSP72 in the myocardium of 32 patients with coronary disease operated in Military-medical academy. HSP72 was detected in probes of the right atria before and after pre-cardiopulmonary bypass in all cases induction of HSP72 was observed in 40% of patients, and directly correlated with the time of cardiopulmonary bypass and standing of the disease. The cardioprotective effect of the elevated pre-operational level of HSP72 was shown to be proportionate to the lower activity of cardiospecific enzymes, creatine phosphokinase (CK-MB). It is suggested that HSP72 is involved in the mechanism of cardioprotection during cardiopulmonary bypass.