Karyotypic variability of human multiple myeloma cell lines

Abstract

Cytogenetic analysis of human multiple myeloma (MM) cell lines L363, Karpas 707, RPMI 8226, and U-266 was carried out. During long-term existence in vitro, the number of chromosomes in the cell lines was shown to be preserved at the near-diploid level (L363, Karpas 707, U-266) or to increase up to the hypotriploid level (RPMI 8226). There were complexly rearranged karyotypes with abnormalities of chromosomes of all pairs in all cell lines; however, no identical chromosomal translocations have been revealed. Loci of chromosomes involved in structural rearrangements in these cell lines often coincided with sites of DNA copy number imbalances characteristic for MM in vivo. Distinct types of the karyotypic structure of cell populations differing in the combination of cells with the main and additional structural variants of karyotype and of cells with nonclonal chromosome rearrangements were found in MM cell lines. In general, the karyotypic variability of the MM cell lines corresponds to the dynamics of karyotype of myeloma cells in vivo and, hence, has a tumor-specific character.