methylnitronitrosoguanidine and Bloom-Syndrome

The MNNG-exposed Bloom syndrome (BS) B-lymphoblastoid cell population (BS-MNNG), when analyzed for aberrant genetic variations, showed an illegitimate rearrangement at the TCR-gamma gene and hypermethylation at the c-myb protooncogene. The TCR-gamma rearrangement involved a Vgamma9 segment corresponding to a 4 kb band detected with a Jgamma-specific probe in HindIII-digested DNA samples from BS-MNNG cells only. These variations were not shown by unexposed BS cells or both MNNG-exposed and unexposed normal (GA3) B-lymphoblastoid cells.

Topics: B-Lymphocytes; Bloom Syndrome; Carcinogens; Cell Line, Transformed; Cell Transformation, Neoplastic; DNA Methylation; Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor; Humans; Methylnitronitrosoguanidine; Oncogenes

Twenty-four hour MNNG-exposed Bloom syndrome (BS) B-lymphoblastoid cells with the potential to form single cell colonies in soft agar and nude mouse tumour (2/6 (33%) showed a simultaneous increase in the Ras-expressing cells (using monoclonal antibody to p21 transforming protein) from 20% (at 24 h) to 85% (on day 30). In contrast, there was an absence of Ras-positive cells in MNNG-exposed fresh lymphocytes (PBMCs) from a healthy subject and a presence of only 11-18% of Ras-positive cells in normal (GA3) and unexposed BS B-lymphoblastoid cells. The Western blot analysis using sera samples from Hodgkin's lymphoma patients showed the presence of proteins of 102 and 68 kDa which in 2D Westerns were observed to be unique to BS-MNNG cells with approximate pIs of 5.3 and 5.7, respectively. It is proposed that BS-MNNG cells provide an interesting in vitro human cell model to generate unique cancer-associated antigen(s) in addition to using this system to understand the primary events associated with neoplastic transformation.

Topics: Antigens, Neoplasm; B-Lymphocytes; Bloom Syndrome; Blotting, Western; Carcinogens; Cell Line, Transformed; Hodgkin Disease; Humans; Methylnitronitrosoguanidine; Proto-Oncogene Proteins p21(ras)

We have cloned malignant cells carrying specific antigens associated with ovarian cancer (OVC) and malignant lymphoma (ML) from BS-SHI-4M cells, a line derived from a 1-methyl-3-nitro-1-nitrosoguanidine-treated B-lymphoblastoid cell line isolated from a patient with Bloom syndrome. Since BS-SHI-4M cells react with sera from various individual cancer patients at relatively low frequencies (2-9%), as detected by an indirect immunofluorescence technique, cell clones that specifically react with sera from patients with OVC and ML were separated by the "panning" method in which polystyrene dishes were coated with sera from OVC and ML patients and cells with the corresponding antigens bound to the dishes. Subsequent cloning by limiting dilution provided cell clones highly enriched for OVC- and ML-associated antigens. Karyotype analyses revealed that cell clones with OVC and ML antigens had common marker chromosomes, der(14)t(14;14) (p11;q11),t(6;?)(p25;?) and t(9;?)(q34;?), besides t(17;?) (q25;?) found in the OVC-antigen-positive clones and t(5;?) (p13;?),t(7;?)(q36;?) found in the ML-antigen-positive clones. Interestingly, in cell clones with a strong OVC antigen response, the distal part of the Y chromosome (Yq11) was missing in 100% of the cells. Therefore the cell line BS-SHI-4M appears to be a reservoir of cell clones each of which carries a specific tumor antigen and thus provides a potential tool for rapid serological diagnosis of cancer.

Topics: Antigens, Neoplasm; Bloom Syndrome; Cell Line; Chromobox Protein Homolog 5; Clone Cells; DNA, Neoplasm; Female; Genetic Markers; Humans; Karyotyping; Lymphoma; Methylnitronitrosoguanidine; Ovarian Neoplasms