[Features of rat cells karyotypic abnormalities in rat cells in their transformation in vitro].

Neoplastic transformation of cells is characterized by karyotypic abnormalities involving aneuploidy, quantitative changes, as well as multiple clonal rearrangements of the number and structure of chromosomes. It is probable that chromosomes are one of the mechanisms of cells immortalization and transformation. Despite many years of study of chromosomal rearrangements, data on primary chromosomal rearrangements in early stages of transformation is still insufficient. We examined karyotypic abnormalities in embryonic rat fibroblasts in both the spontaneous transformation and transformation by oncogenes at different passages in vitro. Literature data and results of our cytogenetical analysis of rat cells lines established by different methods of transformation of cells of different tissue origin in vitro have shown that cell karyotype at early passages may either be normal or acquire diverse clonal chromosomal abnormalities. At later passages, other chromosomes of karyotype are involved in new rearrangements. Despite this, some of the lines do not acquire the malignant phenotype and remain to be immortalized. The role of instable chromosomes and their loci in immortalization and transformation of cells is discussed.

[Characteristics of the spontaneously transformed human endothelial cell line ECV304. I. Multiple chromosomal rearrangements in endothelial cells ECV304].

Karyotype of endothelial line ECV304 cells obtained from human umbilicus vein endothelial cells was studied using G-banding chromosome staining. It has been revealed that the cells have a polyploidy karyotype with 96-112 chromosomes and multiple numerical and structural clonal rearrangements. Almost all the chromosomes of the karyotype are involved in structural rearrangements. There are several double chromosome rearrangements revealed including del(9)(p21) as well as two derivatives of chromosome 3 with the breakpoint in the locus p25 - der(3)t(3;12)(3p25;12q11- 12q24.?1) and der(3)t(3;?)(3p25). The role of these rearrangements in the immortalization of endothelial cells and sighs of transformation are discussed. In connection with the information received about the fact that the cells of ECV304 line are not endothelial cells but T24, urinary bladder cancer cells (which karyotype was studied by Hurst et al., 2000), the comparative analysis of the karyotypes of these two lines was carried out. It has been revealed that these two lines differ by all cytogenetic characteristics. Neither identical structural chromosomal rearrangements nor cell characteristic of urinary bladder cancer cells were detected. Our line ECV304 is not identical to the line T24.

[Chromosomal rearrangements and their effects in spontaneous immortalization and transformation of rat embryo cells in vitro].

G-banding analysis of LRec-1 and LRec-3, spontaneously immortalized cell lines from rat embryo fibroblast, revealed diploid karyotypes with specific clonal structural rearrangements of chromosomes 7 and 19 - del(7)(q11.2q22.1), t(7;19)(q11.1;q12) in malignant stage. Both clonal abnormalities of chromosomes 7 and 19 were also revealed in LRec-1k clone and LRec-1 sf cell line. Previous study of LRec-1 and LRec-3 cells showed the presence of karyotypes with pseudodiploid modal chromosome number, partial trisomy of chromosome 7 and same clonal structural rearrangements of chromosomes 7 and 19 in immortalized stage. In malignant stage, the trisomy 6 and new clonal structural rearrangements of chromosomes 1, 2, 11, 15, 18, 19 and of chromosomes 10, 20 were also found in LRec-1 sf and LRec-1 cells, accordingly. There were no new clonal structural chromosome rearrangements in LRec-1 k and LRec-3 cells. We compared locies of chromosomes involved in rearrangements with mapped genes on these chromosomes according to RATMAP. Supposedly these genes are involved in spontaneous immortalization of rat embryo fibroblast and malignant transformation of LRec-1 and LRec-3 cells and rearrangements of chromosomes 1, 2, 11, 15 and 18 facilitate expression of growth factors of LRec-1 sf cells.

[Age dymamics of stable chromosome aberration frequency in humans with natural and pathological senescence]. / Vozrastnaia dinamika chastoty stabil'nykh khromosomnykh aberratsii u cheloveka pri estestvennom i patologicheskom starenii.

The age dynamics of stable chromosome aberration (SCA) frequency was analysed by fluorescent in situ hybridization (FISH) in human blood lymphocytes derived from donors, irradiated by low doses of ionizing radiation (Chernobyl clean-up workers, nuclear weapon testers, etc.) and patients with hereditary premature aging--Werner's syndrome and Hutchinson-Gilford's syndrome. It was found that the level of SCA was age-dependent and increased in irradiated persons. So, the SCA level may be really an index of a so-called "radiation senescence", and may show a real biological age of irradiated persons. The patients with Werner's syndrome demonstrate increased SCA level in blood lymphocytes, corresponding to the premature aging of the organisms. But in the case of another form of premature aging--Hutchinson--Gilford's syndrome-- no rise of SCA level was found. Some possible reasons of such results are discussed.

[Nuclei with protrusions--"tailed" nuclei--and radiation cytogenetic markers in a lymphocyte culture after x-ray irradiation]. / Iadra s protruziiami--"khvostatye" iadra i radiatsionnye tsitogeneticheskie markery v kul'ture limfotsitov posle rentgenovskogo oblucheniia.

Frequency of the appearance of binuclear cells with nuclei having outgrowth into the cytoplasmic space and arise after first mitosis in human lymphocyte culture is linear-square dependent on the X-irradiation at doses from 0.0 to 4.0 Gy. Positive correlation between frequency of cells with "tailed" nuclei and frequency of metaphases of first mitosis having dicentrics and rings was established. Apparently, formation such "tailed" nuclei is connected with dicentrics and rings.

[A cytogenetic analysis of the cells of spontaneously transformed LREC rat cell lines. I. Chromosomal rearrangements detected in the early stages of rat embryonic cell transformation in vitro]. / Tsitogeneticheskii analiz kletok spontanno transformirovannykh kletochnykh linii krys LREC. I. Perestroiki khromosom, vyiavliaemye na rannikh stadiiakh transformatsii émbrional'nykh kletok krys in vitro.

Seven spontaneously transformed cell lines LREC of rat embryo fibroblasts were obtained by an originally elaborated cloning technique (method 2T7). Six lines (1-6) were obtained from Rattus norvegicus cells, and one line (LREC-7) from Wistar rats. Method 2T7 was based on a serial propagation of rat embryo cells, brought to a "crisis" stage under conditions of a higher cell density and followed by the appearance of actively proliferating cell clones. These lines were analysed cytogenetically at the earliest stages using the Giemsa G-banding technique. In the karyotypes of six LREC (1-6) lines two abnormal chromosomes 7 were revealed: one marker chromosome M1-t(7; 19) results from translocation between chromosomes 7 and 19, the other marker chromosome M2--del(7) is a result of deletion of the second homolog of chromosome 7 in the q11.2 q22.1 loci; besides an extra normal homolog of chromosome 7 was revealed. There are only two marker chromosomes M2 in the LREC-7 line karyotype. Cells of LREC (1-3) lines could be transformed from the immortalized stage to the malignant one by the 30-45th passages. The cells of LREC (4, 7) lines became malignant at the 10-8th passages, resp. The rearrangements of chromosome 7 are supposed to be specific for LREC lines obtained by our method. A hypothesis is put forward that the translocation of chromosome 7 may play an important role for the immortalization of the rat embryo cells. The deletion of chromosome 7 may be associated with a malignant transformation of cells, as it is possible that the deleted loci have a recessive oncogene. Method 2T7 allows to obtain constantly spontaneously transformed cell lines of rat embryo cells with the least abnormal karyotype.

[Chromosomal study of polycythemia during different stages of the disease]. / Issledovanie khromosom pri politsitemii v dinamike zabolevaniia.

A cytogenetic analysis of blood and bone marrow cells of 15 polycythemia vera patients was carried out at different stages of disease during the G-banding technique. Chromosome aberrations of single character were noted before treatment only in one case, i.e. with the patient at stage II of disease. Cell clones with marker chromosomes were revealed in 6 of 9 patients examined in the course of treatment at stages II and III. The cytogenetic analysis was applied to the terminal stage of polycythemia (blast crisis) in one case, when 3 aberrant clones with multiple quantitative and structural chromosome rearrangements were discovered in blood cell cultures with and without PHA. No preferential involvement of definite chromosomes in aberrations was noticed in all the cases examined, no deletion of the 20q --chromosome being discovered. The role of the treatment in the induction of chromosome aberrations is discussed in addition to its dependence on the stage of disease. It is possible that all the clones of pathological character may appear during the long-termed course of polycythemia in patients treated at more serious stages of the disease.