A comparison of bleomycin-induced damage in lymphocytes and primary oral fibroblasts and keratinocytes in 30 subjects

Abstract

The number of chromatid breaks in peripheral blood lymphocytes (PBL) after exposure to bleomycin in the S/G2 phase of the cell cycle (in the literature referred to as 'mutagen sensitivity') is associated with an increased risk of environmentally related cancers, including oral cancer. The aim of this study was to elucidate whether mutagen sensitivity measured in lymphocytes actually reflects chromosomal instability of normal cells in the areas in which tumors develop. Therefore, bleomycin-induced chromosomal damage in and growth inhibition of cultured oral fibroblasts and oral keratinocytes from 30 persons were compared with the standard mutagen sensitivity score in PBL. A correlation was found for the percentage of aberrant metaphases between PBL and oral fibroblasts but not for the number of breaks per cell. These data do not allow a conclusion to be drawn on the use of fibroblasts to study cancer risk. Within the fibroblasts it was found that a high number of breaks per cell was associated with less growth inhibition, indicative of damage-resistant growth. Oral keratinocytes were extremely sensitive to bleomycin, as indicated by a strong cell cycle block which resulted in a mitotic index too low to determine chromosomal breaks. Moreover, in the cell proliferation assay keratinocytes were found to be 100 times more sensitive as compared with fibroblasts. There was no correlation between bleomycin sensitivity of keratinocytes compared with fibroblasts from a single patient as measured by growth inhibition. This may be due to the strong influence of alcohol consumption by the subjects, which was found to increase the sensitivity of keratinocytes but not of PBL and fibroblasts. In conclusion, oral fibroblasts but not keratinocytes can be used to measure sensitivity for chromatid breaks. The apparent influence of environmental factors on keratinocytes makes them a useful source to study exposure characteristics but limits their application for the determination of genetic factors.

Predicting how cells spread and migrate

“…had not been previously reported to play a role in cell migration or in the formation of focal adhesions, [28][29][30] modulated focaladhesion formation, and cell migration in ways quantitatively predicted by the pre-established biphasic relation. Finally, the biphasic relationship established with MEFs was further validated with HT-1080 cells, a highly tumorigenic human fibrosarcoma cell line.…”

Human Lymphoblastoid Proteome Analysis Reveals a Role for the Inhibitor of Acetyltransferases Complex in DNA Double-Strand Break Response

“…In turn, the signal transducers activate a broad range of effector proteins, for example, those involved in cell cycle arrest (33,34). A relatively fast response was found for the effector protein isoforms 14-3-3~/y, of which the 14-3-3 protein~is known to be involved in cell cycle regulation through binding to Cdc25 (35,36).…”

Microarray Analysis of Bleomycin-Exposed Lymphoblastoid Cells for Identifying Cancer Susceptibility Genes

“…Cell lines made in this way show a very good concordance in mutagen sensitivity score with the original lymphocytes (17) and are proposed to reflect the capacity of an individual to deal with bleomycin-induced DNA damage (11). Our laboratory has prepared various lymphoblastoid cell lines from HNSCC patients and noncancer individuals according to a previously published protocol (17).…”

“…A high mutagen-sensitive phenotype (having more than a mean of 1.0 b/c) was found at higher frequency in patients not only with HNSCC but also with lung and colon cancer compared with the control population without cancer (4)(5)(6)(7)(8)(9). Mutagen sensitivity is not influenced by gender, tumor stage, or smoking and alcohol intake of the subjects and only slightly increases with age (4,10,11); it is considered to be an intrinsic factor, reflecting how an individual copes with DNA damage (12). In combination with carcinogenic exposure (smoking and alcohol intake), a mutagen hypersensitivity phenotype is associated with a greatly increased risk of developing HNSCC (13).…”