Spontaneous premature condensation of chromosomes in normal and transformed mammal cells

To study the relation between premature chromosome condensation and the ability of the cells to undergo malignant transformation.

Standard cytogenetic analysis of bone marrow cells and cultured normal and tumor cells has been used.

Comparative analysis of the frequency of occurrence of the cells with premature chromosome condensation (PCC) (cell "arrest" at G2/M phase) in relation to dividing cells in the cultures of human immortalized cells of hematopoietic origin, human lung carcinoma A-549 cells, and in populations of bone marrow cells of BALB/c and C57BL/6 mice differing in predisposition for myeloma development has been performed. It has been revealed that in populations of bone marrow cells of C57BL/6 mice the relation of cells with PCC to dividing ones is 2-3-fold lower than in other studied cell populations. Immortalized and malignantly transformed human cell lines were characterized by high frequency of occurrence of cells with PCC. In the cells of A-549R subline characterized by suppressed malignant phenotype this index was lower than in parental A-549 cells.

The obtained data point on possible relation between disturbed passing of "check point" by cells upon transition from G2 phase of cell cycle to mitosis and increased genetic heterogeneity of new cell generation associated with ability of cells to immortalization and malignant transformation.