The African-specific S47 polymorphism of p53 alters chemosensitivity.

The TP53 protein is known to affect the sensitivity of tumor cells to cell death by DNA damaging agents. We recently reported that human and mouse cells containing an African-specific coding region variant of p53, Pro47Ser (hereafter S47), are impaired in the transactivation of a small subset of p53 target genes including GLS2 and SCO2, and are markedly resistant to cisplatin. Further, mice containing this variant are markedly predisposed to cancer. Together these findings suggested that cancer-affected humans with the S47 variant might not be effectively treated with cisplatin. To more directly test this premise, we created transformed derivatives of mouse embryo fibroblasts (MEFs) containing wild type p53 (WT) and the S47 variant and analyzed them for chemosensitivity. We find that transformation with E1A and Ras actually reverses the chemosensitivity/transcriptional differences between WT p53 and S47. Specifically, E1A/Ras-transformed S47 cells show increased sensitivity to cisplatin and paclitaxel, and comparable transactivation of GLS2 and SCO2, compared to cells with WT p53. These data suggest that the functional differences between WT p53 and S47 in primary cells may not hold true for transformed cells. They also offer hope that cisplatin and paclitaxel may be effective chemotherapeutic drugs for S47 individuals with cancer.