MODIFICATION OF THE TUMOR/INDUCED BYSTANDER EFFECT BY IRRADIATION UNDER COCULTIVATION OF LYMPHOCYTES FROM PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA AND LYMPHOCYTES FROM HEALTHY DONORS

Abstract

Objective: Study the tumor-induced bystander effect of blood cells from chronic lymphocytic leukemia (CLL) patients on non-transformed bystander cells (peripheral blood lymphocytes (PBL) of conditionally healthy individuals) and the possibility of its modification after the impact of ionizing radiation. Materials and methods. We carried out cocultivation and separate cultivation of blood samples from conditionally healthy volunteers and patients with CLL according to our technique. Using the Comet assay, the relative level of DNA damage was evaluated. Results. A statistically significant increase (р < 0.001) in the level of DNA damage in PBL culture of conditionally healthy individuals after co-cultivation with malignant cells of CLL patients was observed. After irradiation, a drop in the level of cells with a high degree of DNA damage was noted, which was connected with an increase in the frequency of cells that were delayed in division at the S stage of the cell cycle. An increase in apoptotic activity in cultures of bystander cells was observed in all variants of the experiment (р < 0.001). Conclusion. The influence of irradiated blood cells of patients with CLL results in an enhancement of the tumorinduced bystander effect manifestation in the PBL of conditionally healthy individuals. Key words: tumor-induced bystander effect, peripheral blood lymphocytes, Comet assay, ionizing radiation.