Lysosomal
proteases are actively involved in pathogenesis of
cancer progression. Alterations in
proteases and their inhibitors interaction were suggested to be implicated in the processes of
tumor invasion and
metastasis. Among
proteases connected with malignant growth,
cysteine cathepsins B and L and aspartic
cathepsin D play the main role in the
tumor development. The present study was designed to investigate activity of
cathepsins B, L and D activity in the development and treatment of murine
experimental leukemias and to determine the correlation of these
proteases with
tumor malignancy and the
chemotherapy effect. P-388
leukemia was characterized by a more aggressive development and unfavorable prognosis than L1210/1
leukemia. The activity of
cathepsins B, L and D in
tumor tissues of mice infected with P-388
leukemia, as well as in liver and spleen and the activity of
cathepsins B and L in serum were lower than their activity in mice infected with L1210/1
leukemia. Changes of
cathepsin activity in liver and spleen of mice with
leukemias have demonstrated a level of aggressiveness of
tumor development and invasion of liver and spleen by neoplastic cells. The treatment resulted in the increase of
cathepsin B, L and D activities in
tumor tissue, liver, spleen and
cathepsin B and L activities in serum. The highest activity of
proteases was revealed in the groups of mice characterized by the greatest suppression of
tumor growth. These data have shown that lysosomal
proteases are involved in progression of murine
experimental leukemias and elimination of
tumor cells in the result of treatment. Determination of the activity of
cysteine and aspartic
proteases can be used for evaluation of
cancer diseases
malignancy, their sensitivity for
chemotherapy and efficiency of treatment.