Abstract

The antibacterial peptide cecropin B mutant (ABPS1) gene has a broad range of antibacterial and antiproliferative properties. Apoptin (VP3), a chicken anaemia virus-encoded protein is known to induce apoptosis in human transformed cells. To explore drug combination in human tumor cells, apoptin and ABPS1 eukaryotic expression vector pIRES2-EGFP-apoptin and pIRES2-EGFP-ABPS1 were constructed and their expression effect individually and in combinations were studied in HepG2 and A375 cells. The vector pIRES2-EGFP-ABPS1 and pIRES2-EGFP-apoptin were transfected into tumor cells HepG2 and A375 by the lipofectamine-mediated DNA transfection procedure. At 48 h post transfection, the apoptotic rate obtained by flow cytometry and the morphological changes under light and scanning electron microscope of tumor cells were significant. In contrast, the microvilli on the surface of the control cells were disrupted, decreased and even disappeared. The cell membrane was injured and intracellular substances leaked out. Furthermore, our results indicate that the apoptotic rates of apoptin (27.32% in HepG2 and 9.34% in A375 cells), were higher than ABPS1 (23.79% in HepG2 and 8.33% in A375 cells). Moreover, the co-expression of Apoptin and ABPS1 showed higher apoptotic rates which were 27.66 and 10.33% in HepG2 and A375 cells respectively. However, the apoptotic rates obtained in HepG2 cells treated with apoptin and apoptin and ABPS1 together were closely similar, but, not in A375 cells. Therefore, the results of the present study showed that the combination of Apoptin and ABPS1 has synergistic effect in HepG2 and A375 cell lines.

Keys words: Apoptin, ABPS1, apoptosis, co-expression, HepG2, A375.

Abbreviation

ABPS1, Antibacterial peptide cecropin B mutant; VP3, apoptin; FACS, fluorescent activated cell sorting