Effect of Cathepsine L1 on Transformation of Malignant Melanoma B16 Cells into Melanocytes.

We studied the effects of cathepsins produced by immunocompetent cells of intact mice, mice with B16 melanoma, mice with removed B16 melanoma, and mice with removed Ehrlich carcinoma on the growth of B16 melanoma. Incubation of B16 melanoma cells with cathepsins from immunocompetent cells of intact mice, mice with B16 melanoma, and mice with removed Ehrlich carcinoma did not affect tumor growth. Incubation of B16 melanoma cells with cathepsin from immunocompetent cells of mice with removed B16 melanoma was followed by complete loss of malignancy by these cells. Melanoma cells formed no tumor node within at least 1 year after transplantation, though exhibited high proliferative activity and formed pigmented nevi. The formation of a nevus by B16 melanoma cells is described for the first time. The existence of a mechanism regulating proliferation of malignant cells in the tumor-bearing host was hypothesized. Studies of this mechanism are expected to promote the development of new methods for the treatment of tumors.

Changes in the serum protein composition in mice with transplanted Ehrlich's carcinoma.

Injection of blood serum from mice with Ehrlich's carcinoma stimulates the growth of transplanted tumor, which proves the presence of tumor-specific factors in the serum. Experiments on (CBA×C57Bl/6)F1 male mice with transplanted Ehrlich's carcinoma demonstrated the appearance of new proteins in the serum, some of them are identified. The authors suggest continuing the search for tumor-associated factor by combining proteomic analytical methods and testing of identified candidate proteins for their effects on tumor growth.

[Antioxidant system of platelets in patients with ovary cancer]. / Antioksidantnaia sistema trombotsitov u bol'nykh rakom iaichnikov.

The activities of lipid peroxidation and of platelets' antioxidant protection were investigated in 30 healthy women and in 44 patients with primarily diagnosed different-stage ovary cancer (OC). An essentially higher activity of superoxide dimutase (SOD, by 2.5 times) and of catalase (by 1.5 times) was detected in platelets of OC patients versus the norm. A simultaneous increase of malonic dialdehyde (MDA) by 2.5 times denotes a free-radical activation. There was also an insignificant growth of the glutathione level, whereas the activity of glutathione-S-transferase (GST) did not virtually change. A comparative analysis of the biochemical indices of patients with different stages of the disease revealed valuable distinctions related with a higher activity of SOD and catalase in stages 3-4 versus the initial stages. Notworthility, the MDA level was decreasing. Minor changes in the system of glutathione are not obviously decisive in impairing the regulatory mechanism of antioxidant protection in platelets unlike in malignant cells. The results provide a solid basis for assuming that the impact made by deranged regulations of free radicals on the platelet chain in the hemostasis system causes changes in the blood rheological properties entailing a higher aggregation of platelets, thus, triggering the onset of platelet-embolic complications in the discussed patient category. The impaired regulation mechanism of antioxidant protection in platelets is a major manifestation of the oxidant stress evolving due to a growing tumor; the mechanism is important for evaluating the structural-and-functional platelets' condition.

[The oxidative stress in platelets of patients with ovary cancer as observed at chemotherapy]. / Okislitel'nyi sress v trombotsitah bol'nykh rakom iaichnikov v protsesse khimioterapii.

Disorders in the main chains of platelet antioxidant protection were examined in 32 patients with primarily-diagnosed ovary cancer who were postoperatively receiving chemotherapy according to PC. The activity of antioxidant-protection enzymes (superoxide dismutase, catalase, glutation-S-transferase) as well as the content of malonic dialdehyde (MDA) and glutathione were examined after each course of chemotherapy. The data obtained were compared with the aggregation ability of platelets, with the content of fibrinogen and with the count of platelets. The parameters of the antioxidant system in platelets were examined for control in 30 virtually healthy women. The results denote that the oxidant stress progression in the body due to the growing tumor and aggravating because of chemodrugs deregulates the free-radical processes in platelets, which can affect their functional properties or rheological blood properties.

Role of glutathione-dependent peroxidase in regulation of lipoperoxide utilization in malignant tumors.

Glutathione content, the activity of glutathione-dependent enzymes (glutathione reductase, glutathione peroxidase, and glutathione S-transferase), and also SOD (superoxide dismutase) and catalase were studied in human malignant tumors (uterus, breast, and ovaries) and normal tissues. Glutathione level and the activity of glutathione-dependent enzymes were 2-3 times higher in the malignant tumors than in normal tissues. A negative correlation between the level of glutathione and glutathione-dependent enzymes (glutathione peroxidase and glutathione S-transferase) in tumors and the efficacy of postoperative chemotherapy may characterize the degree of tumor resistance to chemotherapy and therefore may have prognostic value. Low SOD and catalase activity and high activity of glutathione-dependent enzymes in tumors suggest that glutathione peroxidase and glutathione S-transferase play a major role in peroxide utilization in malignant tumors.

Immunotoxicological characteristics of preparations based on carcinoembryonic antigen and mucin containing CA 125 antigen.

Experiments on male hybrid mice demonstrated that specific immunotherapy with preparations based on carcinoembryonal antigen and mucin containing CA 125 antigen was not associated with general toxicity, local irritating effect, and hepatorenal dysfunction. The absence of toxicity is apparently due to the fact that antigens injected intramuscularly or subcutaneously virtually do not enter the blood. Injections of preparations based on carcinoembryonal antigen and mucin containing CA 125 antigen to mice induced a standard immune response with predominance of class M immunoglobulins during the early terms and class G immunoglobulins at later terms.