C-terminal domain of human CAP18 antimicrobial peptide induces apoptosis in oral squamous cell carcinoma SAS-H1 cells

Mammalian myeloid and epithelial cells express many antimicrobiotic peptides that contribute to innate host defense against invading microbes. In the present study, a 27-mer peptide of the C-terminal domain (hCAP18109–135) and analogs of the antimicrobial peptide human cathelicidin LL-37/human cationic antimicrobial protein 18 (hCAP18) were examined for tumoricidal activity. In vitro results showed that hCAP18109–135 induced apoptosis in human oral squamous cell carcinoma (OSCC), SAS-H1 cells. The hCAP18109–135 induced mitochondrial depolarization and apoptosis in SAS-H1 cells, but not in healthy human gingival fibroblasts (HGF) and human keratinocyte line HaCaT cells. Caspases were not activated during hCAP18109–135-induced apoptosis in SAS-H1 cells. The results indicate that hCAP18109–135 may induce caspase-independent apoptosis in OSCC but not in normal cells. hCAP18109–135 can therefore be a useful anti-tumor therapeutic agent in the treatment of OSCC.