Researchers found that a natural saliva protein called histatin‑1 can boost the cancer‑killing effect of the chemotherapy drug cisplatin in lab-grown head‑and‑neck cancer cells, allowing lower drug doses to work better.

Chemotherapy of head and neck squamous cell carcinoma (HNSCC) is associated with significant side effects. Antimicrobial peptides (AMPs), which are naturally occurring defense molecules like defensin-1 and LL-37 found in human secretions, have demonstrated potential in prompting tumor cell apoptosis and enhancing the effect of chemotherapeutic agents. However, the anticancer potential of histatin has not yet been thoroughly examined. The aim of the study was to explore the anticancer activity of histatin, an AMP present in human saliva and used alone or in combination with cisplatin in HNSCC cell lines. The gene expression of histatin was evaluated in the HSC4 and SCC25 cell lines by qRT-PCR. Cell proliferation was investigated at different concentrations of histatin peptide (His-1), cisplatin, and their combination using an MTT assay. SCC25 cells expressed both HTN1 (histatin-1) and HTN3 (histatin-3), whereas the HSC4 cell line expressed only HTN1. The combination of exogenous His-1 and cisplatin demonstrated a synergistic anti-proliferative effect against the HNSCC cell lines in a dosedependent manner. The combination of low-dose cisplatin and histatin inhibits HNSCC cell proliferation. His-1 sensitizes tumor cells to the cytotoxic effects of cisplatin potentially allowing for a reduction in its effective concentration.