The influence of the p53 gene on the in vitro chemosensitivity of colorectal cancer cells

Purpose: The p53 gene is considered one of the most important in the contro l of apoptosis, and its mutations have a close relationship with chemosensi tivity. The aim of this work was to investigate the role of p53 in the apop tosis of colorectal cancer cells in vitro, induced by 5-fluorouracil (5-FU) and hydroxy-camptothecin (HCPT). Methods: A total of 39 colorectal cancer samples from patients were treated in vitro with 5-FU (10 mu g/ml), 5-FU (1 0 mu g/ml) + leucovorin (5 mu g/ml), HCPT (0.1 mu g/ml) and HCPT (0.1 mu g/ ml) + Salvia mitorrhiza (6 mu l), using an in situ terminal deoxynucleotidy ltransferase assay to detect chemosensitivity. p53 gene mutations from tumo r DNA were detected, after amplification by the polymerase chain reaction o f exons 5-8, by non-radioactive single-strand conformation polymorphism. Re sults: p53 gene mutations were observed in 43.6% (17/39) of colorectal carc inomas, when the terminal deoxynucleotidyltransferase assay was used to det ect the tumor apoptotic rate. Cells with mutated p53 had lower chemosensiti vity than those without (p < 0.01). Conclusion: Routine assessment of p53 s tatus may be helpful in selecting patients with the wildtype p53 gene, who have a predictably better response to chemotherapy.