Figure 3.

NaBu, TSA, and p21 overexpression inhibit growth of HT-29 cells. (A) NaBu and TSA inhibit growth of HT-29 cells. Cells were plated at equal density in six-well plates. At 80% confluence, cells were treated without or with 5 mM NaBu or 0.3 μM TSA for 24 hr. ³H-thymidine (1 μCi/ml) was added for the last 6 hr of treatment, and incorporation was measured by scintillation counting. Treatment results are expressed as percent change compared with untreated negative control, arbitrarily taken as 1. (B) p21 overexpression inhibits growth of HT-29 cells. Cells were stably transfected with an expression plasmid containing the human p21 gene, and overexpression of the gene in pooled stable transfectants compared with the parental and NEO controls (n = 5 each) was determined by Northern analyses (see Inset). ³H-thymidine incorporation was measured in exponentially growing cells under basal conditions, and results are expressed as percent change compared with parental control, arbitrarily taken as 100%, and are shown as mean ± SEM (n ≥ 4, in all cases).