Antitumor Activity of Human β Defensin 4 in Vitro

Objective: Human β defensin 4(HBD4) has been shown to be a promising candidate for a new antimicrobial peptide against bacteria. However, little is known about its function in cancer. Our objective is to explore its antitumor activity in vitro. Methods: Recombinant vector pcDNA3.1/HBD4 was constructed and transfected into HEK293 and HEp2 cells with Lipofectamine. HBD4 transcription and protein expression were examined by RT-PCR and Western-blot. Cell growth was analyzed by MTT assay and standard phase-contrast light microscopy. Membrane integrity of the HBD4-transfected cells was assessed by scanning electron microscopy. Results: Expression of HBD4 was detected in both lysates and the supernatant of the HBD4-transfected HEK293 and HEp2 cells. It was showed that HBD4 expression can selectively inhibit the growth of HEp2 cells, but not HEK293 cells. Cell membrane perforation and apoptotic body formation were observed in the HBD4-transfected HEp2 cells, while HBD4-transfected HEK293 cell show a smooth surface. Conclusions: HBD4 exerts a significant selective cytotoxic and antiproliferative efficacy on HEp2 cells, which suggests that HBD4 may function as a cytotoxic agent for cancer treatment.