Mutation and expression analysis of human BUB1 and BUB1B in aneuploid breast cancer cell lines.
Genetic instability is a hallmark feature of breast, colorectal and other types of cancers. One type characterized by chromosomal instability is thought to be important in the pathogenesis of many solid tumors displaying aneuploidy. Two related protein kinases and homologues of the yeast checkpoint genes, hBUB1 and hBUB1B, have been implicated in the pathogenesis of colorectal cancers. Mutations in hBUB1 have demonstrated a dominant negative effect by disrupting the mitotic checkpoint when transfected into euploid colon cancer cell lines. In Brca2 deficient murine cells, Bub1 mutants potentiate growth and cellular transformation. This would suggest that aneuploidy in solid tumors including breast, could be the result of defects in mitotic checkpoint genes and may be responsible for a chromosomal instability phenotype contributing to tumor progression. We conducted mutational analysis of 19 aneuploid breast cancer cell lines. No mutations were found but we identified nine sequence variations including five previously unreported sequence variants in hBUB1B, two of which affect restrictions sites. None of these nucleotide changes predict significant changes in the predicted protein structure. Expression analysis by Northern blot of breast cell lines showed variable expression of hBUB1 and hBUB1B genes. This suggest that while regulation of expression of these genes may be important in cancer, the lack of putative deleterious mutations in the coding sequence does not support a frequent role for mutant hBUB1 and hBUB1B alleles in the pathogenesis of breast cancer.
Myrie
K A
KA
Department of Human Genetics, University of Michigan Medical School, Ann Arbor 48109-0638, USA.
Percy
M J
MJ
Azim
J N
JN
Neeley
C K
CK
Petty
E M
EM
D000483:Alleles; D015152:Blotting, Northern; D015139:Blotting, Southern; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism*; D003062:Codon; D004252:DNA Mutational Analysis; D005260:Female; D006801:Humans; D009154:Mutation; D010641:Phenotype; D011003:Ploidies; D011110:Polymorphism, Genetic; D011494:Protein Kinases / Q000096:biosynthesis* / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
D003062:Codon; D011494:Protein Kinases; C584277:BUB1 protein, human; C090464:Bub1 spindle checkpoint protein; D017346:Protein Serine-Threonine Kinases