Interphase fish analysis of cell cycle genes in asbestos-treated human mesothelial cells (HMC), SV40-transformed HMC (MeT-5A) and mesothelioma cells (COLO).
The epidemiologic association between asbestos exposure and human malignant mesothelioma is well established. However, the molecular mechanisms linking asbestos exposure of humans and the subsequent mesothelioma formation is not well understood. The most frequent genetic changes found so far in human malignant mesothelioma (HMM) are deletions and point mutations in the tumor suppressor genes p16INK4a and NF2. Whereas homozygous deletions appear to be the predominant mechanism leading to p16/CDKN2A inactivation, inactivating point mutations coupled with allelic loss mainly occur at the NF2 locus. In the present study, asbestos-treated human mesothelial cells (HMC), SV40-transformed human mesothelial cells (MeT-5A) and a human mesothelioma cell line (COLO) were investigated for genetic changes of cell cycle genes (cyclin D1, p16INK4a, RB1, CDK2) using multicolor fluorescence in situ hybridization (mFISH) in interphase cells. The results show that cyclin D1 is unaffected in all investigated cells. The p16INK4a gene locus was shown to be mutated in COLO cells but not in HMC. After labeling of CDK2 and RB1, hemizygous loss of one allele of each gene was observed in asbestos-treated HMC whereas gene amplification of these genes was detectable in MeT-5A and COLO cells. Our data indicate that disarrangement of the RB1 dependent pathway seems to be involved in mesothelioma formation.
Dopp
Elke
E
Institute of Hygiene and Occupational Health, University of Essen, Hufelandstrasse 55, 45147 Essen, Germany. elke.dopp@uni-essen.de
Poser
Ina
I
Papp
Thilo
T
D001194:Asbestos / Q000633:toxicity*; D018929:Cell Culture Techniques / Q000379:methods; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics*; D002471:Cell Transformation, Neoplastic; D019938:Cyclin D1 / Q000235:genetics*; D004848:Epithelium / Q000187:drug effects* / Q000473:pathology; D016147:Genes, Tumor Suppressor / Q000187:drug effects; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008654:Mesothelioma / Q000235:genetics* / Q000473:pathology; D009693:Nucleic Acid Hybridization; D017354:Point Mutation; D017384:Sequence Deletion; D013539:Simian virus 40 / Q000235:genetics*; D014407:Tumor Cells, Cultured
D001194:Asbestos; D019938:Cyclin D1