Study on the penetrability of PEP-1-P27mt for cell membranes in vitro.

Double-stranded oligomeric nucleotide encoding PEP-1 peptides was synthesized, prokaryotic expression pET15b-pep-1-p27mt recombinant constructed, E. coli BL21 (DE3)pLysS transformed and induced with IPTG to highly express fusion protein PEP-1-P27mt. Fusion protein with an N-terminal His-tag could be purified by Ni2+-resin affinity chromatography and identified by SDS-PAGE and Western blotting. Cultured EC9706 cells treated with PEP-1-P27mt revealed that PEP-1-P27mt was transduced into cells after 15 min and reached maximal intracellular concentrations in 2 h. PEP-1-P27mt of 1 micromol/L final concentration could most strongly suppress the growth. It was suggested that PEP-1 can carry P27mt across membrane, which provides a new biological protocol for using cyclin dependent kinase inhibitors p27mt in suppressing the growth of tumor cells.