Effect of a two-base insertion mutation of the gene on expression of p53 protein in canine histiocytic sarcoma cells.

OBJECTIVE

To examine effects of a common mutation (2-base insertion in exon 5) of the gene on biological function of p53 protein in canine histiocytic sarcoma cells.

SAMPLE

Canine histiocytic tumor cell lines DH82 with deletion of and CHS-3 with the wild-type and canine wild-type and mutant fragments.

PROCEDURES

Wild-type or mutant with a polyprotein peptide tag at the N-terminus was transduced into DH82 and CHS-3 cells. Expression of p53 protein, changes in function as a transcription factor, and susceptibility to doxorubicin and nimustine were compared.

RESULTS

Transduced p53 protein was detected in wild-type -transduced DH82 and CHS-3 cells, whereas expression was not detected in mutant -transduced cells. There were significant increases in expression of target genes of p53 protein, including and , in wild-type -transduced cells, compared with results for native and mock-transfected cells, but not in mutant -transduced cells. There was no significant difference in drug susceptibilities among native and derivative cells of CHS-3. However, cell viabilities of wild-type -transduced DH82 cells incubated with doxorubicin were significantly lower than viabilities of native, mock-transfected, and AT insertion mutation--transduced DH82 cells; susceptibility to nimustine did not differ significantly among cells.

CONCLUSIONS AND CLINICAL RELEVANCE

Expression of p53 protein and its function as a transcription factor were lost after addition of a 2-base insertion in the gene in canine histiocytic tumor cells. Additional studies are needed to investigate the clinical relevance of this mutation in histiocytic sarcomas of dogs.