Genetic alterations of cancer-related genes in glass fiber-induced transformed cells.
Our previous studies have shown that glass fibers induced morphological transformation in BALB/c-3T3 cells and that transformed cells possessed preneoplastic properties and transforming genes. In the current study, possible molecular mechanisms of glass fiber-induced cell transformation related to the activation and/or inactivation of cancer-related genes resulting from gene amplification and/or point mutations were investigated. Gene amplification was determined by Southern blot analysis of K-ras, H-ras, c-myc, and c-fos proto-oncogenes. Mutational spectra of the p53 tumor suppressor gene and the K-ras proto-oncogene were characterized by single-stranded conformation polymorphism and DNA sequencing. Southern blot analysis showed that gene amplification was found in 56% (K-ras and c-myc), 67% (c-fos), and 100% (H-ras) of glass fiber-transformed cell lines. DNA sequencing analysis revealed that both transition and transversion mutations occurred and were concentrated in exon 2 of K-ras and exon 4 of p53. In addition, multiple mutations in different codons were found in K-ras and p53 These results suggest that (1) glass fiber-induced cell transformation could be attributed to the activation of the H-ras, K-ras, c-myc, and c-fos proto-oncogenes and/or the inactivation of the p53 tumor suppressor gene by gene amplification and/or point mutations and (2) multiple mutations might be due to genomic instability resulting from chromosomal alterations induced by glass fibers.
Whong
W Z
WZ
Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia 26505-2888, USA.
Gao
H G
HG
Zhou
G
G
Ong
T
T
D016475:3T3 Cells; D000818:Animals; D015139:Blotting, Southern; D002461:Cell Line, Transformed; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000032:analysis / Q000096:biosynthesis; D016158:Genes, p53 / Q000235:genetics*; D005898:Glass; D051379:Mice; D008807:Mice, Inbred BALB C; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D011519:Proto-Oncogenes / Q000235:genetics*; D017422:Sequence Analysis, DNA
D017931:DNA Primers; D018076:DNA, Complementary; C009753:fiberglass