Abstract: Objective To explore whether anti-tumor drug FTY720 participates in regulation of p53-dependent gene transcription and to evaluate the potential roles of FTY720-p53 axis in the modulation of cellular biological processes. Methods CRISPR-Cas9 technique was used to generate a p53-knockout (p53-KO) cell strain with human osteosarcoma cell line U2OS that expressed the wildtype p53. Control cells or p53-KO cells were treated with or without FTY720 and the transcriptional was then assessed by RNA-sequencing (RNA-seq) analysis. The differentially expressed genes as well as their potential functions were annotated through bioinformatic analysis. Results The U2OS p53-KO cell strain was successfully established. 220 p53-dependent downstream genes were identified in response to FTY720 treatment. These genes were functionally enriched in the regulation of multiple biological processes including negative regulation of platelet activation, cellular response to chemokine, positive regulation of Rho protein signal transduction, multicellular organismal homeostasis, mucin type O-glycan biosynthesis, ECM-receptor interaction, viral protein interaction with cytokine and cytokine receptor. Conclusions p53 activation is involved in FTY720-mediated tumor suppressive functions.

Key words: p53, FTY720, U2OS, gene expressional regulation, bioinformatic analysis