Transglutaminase in cell proliferation and transformation.

Transglutaminase (TGase) activity was reduced in intact mitogen-stimulated human peripheral blood lymphocytes (PBL) when compared to intact resting PBL. Moreover, a treatment of the same quiescent immunocompetent cells with purified liver TGase and Ca2+ completely suppressed the mitogen-induced blast transformation. A decrease in TGase activity in neoplastically transformed seminal vesicle epithelial cells with respect to their normal parent counterpart was also observed. Our data support the notion of a possible implication of TGase in cell proliferation and transformation.

Induction of tumorigenesis and chromosomal abnormalities in human amniocytes infected with simian virus 40 and Kirsten sarcoma virus.

Cell cultures of epithelial-like human amniocytes were infected with simian virus 40 (SV40) and Kirsten sarcoma virus (KSV) in various sequential orders, and tested for agar growth, chromosome abnormalities, and tumorigenesis in the nude mouse assay. We observed that regardless of the order in which the viruses were introduced, the doubly infected cells always exhibited the typical SV40 premalignantly transformed phenotype before changing to the malignant phenotype. All doubly transformed cells from different cell donors produced tumors in adult and suckling nude athymic mice, classified as poorly differentiated sarcomas. Infection with SV40 alone conferred extended life span and accelerated growth without the malignant capability of tumor production. Kirsten sarcoma virus alone produced only focal cell alterations with no change in cell longevity or tumorigenesis. Chromosome studies of the premalignant and malignant cells from one cell donor did not reveal any significant clonal development for marker chromosomes in either cell line. Chromosome 12, which carries the homologous cellular oncogene to KSV, had no increase in aberrations in the malignant cells. Chromosome 8 was most often involved in aberrations, and the most frequent aberration for both series was dicentric chromosomes due to telomere fusion. For other translocations the breakpoints were almost exclusively in the centromere regions. The vulnerability of telomere and centromere regions to the free virus present in these precrisis cells is discussed, and similarities in regard to types of aberrations in transfection experiments are noted.

[Surface morphology of normal and virus-transformed cells in suspended state and their concanavalin A agglutinability]. / Morfologiia poverkhnosti normal'nykh i transformirovannykh virusami kletok v suspendirovannom sostoianii i ikh aggliutinabel'nost' konkanavalinom A.

Suspended cells are heterogeneous in respect to their surface microrelief. The distribution of different microrelieves varies in different cultures. It depends on the mode of cell detachment from the substrate - by EDTA or trypsin. Oncogenic transformation is accompanied by both the increase and decrease of microvillous microrelief. There is no correlation between the surface morphology of transformed cells and their agglutinability by concanavalin A. The treatment with trypsin results in the increase of both agglutinability by concanavalin A and microvillious microrelief.