Novel protein pp3501 mediates the inhibitory effect of sodium butyrate on SH-SY5Y cell proliferation.

Sodium butyrate, a new potential therapeutic drug, improves the efficacy of chemo- and immunotherapy of cancer under unknown mechanisms. A novel gene pp3501 is significantly induced in SH-SY5Y neuroblastoma cells upon sodium butyrate treatment. Therefore, this study has cloned pp3501 cDNA by RT-PCR and generated its recombinant fusion protein and anti-serum subsequently. The pp3501 protein localized mainly in the nucleus, as detected by immunocytochemistry and the expression of pp3501-EGFP fusion protein. pp3501 inhibited the proliferation of SH-SY5Y cells, arrested the cell cycle at G1 phase, and sensitized the SH-SY5Y cells to sodium butyrate treatment. These results provide a new mechanism of sodium butyrate inhibiting cancer cell proliferation as well as a new avenue for the future research on the functions of pp3501.