Variability in the induction of alkaline phosphatase by histone deacetylase inhibitors in bladder and colon cancer cell lines

Induction of alkaline phosphatase activity has provided a convenient marker for differentiation of colon cancer cells. The degree to which different histone deacetylase inhibitors induce alkaline phosphatase and dipeptidyl peptidase activities was compared in bladder and colon cancer cell lines. The objective was to determine whether bladder cancer cell lines that retain activities of the cell surface hydrolases exhibit regulatory effects similar to those previously observed in colon cancer cells. Effects of histone deacetylase inhibitors on growth and alkaline phosphatase and dipeptidyl peptidase activities were studied in three human colon cancer cells and three bladder cancer cell lines. Growth inhibition was observed with all the histone deacetylase inhibitors that were examined. There was variability in the induction of enzyme activity with different histone deacetylase inhibitors but when induction was observed it was greater for alkaline phosphatase than for dipeptidyl peptidase. The data suggested that regulation of alkaline phosphatase and dipeptidyl peptidase activities by histone deacetylase inhibitors can be similar in bladder and colon cancer cells. However, the functional role of the enzyme activities in bladderderived cells remains to be established.