Evaluation of anticancer activity of α-defensins purified from neutrophils trapped in leukoreduction filters

Aims: The alpha-defensins or human neutrophil peptides (HNP 1-3) that exist in azurophilic granules are found to have anticancer activity. The pattern of disulfide bonds in alpha-defensins is crucial for the functional properties. Therefore, synthesis using the chemical and recombinant approaches is a challenging. A safe source for the production of a-defensins can be the use of leukoreduction filters in blood banks that contain large quantities of neutrophils and are discarded after use. The aim of this study was to purify a-defensins from neutrophils trapped in leukofilters and to investigate its anticancer activity. Materials and methods: Immunoprecipitation was performed to purify a-defensins and the presence of protein was confirmed by Western Blot. The Jurkat T-cell line was incubated with different concentrations (5, 10 and 15 mu g/ml) of purified HNP1-3 for 16 h. Cell viability was measured using a WST-1 assay and apoptosis was analyzed for Annexin V/PI markers. Caspase-3/7 activity was determined using fluorescence assay. The effects of purified alpha-defensins were compared to commercial HNP 1-3. Key findings: Purified HNP 1-3 decreased the viability at 10 and 15 mu g/ml and commercial HNP 1-3 at 15 mu g/ml concentrations. Following to the purified HNP1-3 treatment, the percentage of Annexin V positive population and caspase-3 activity were significantly increased compared to control (p = 0.000 and p = 0.001, respectively) and commercial HNP1-3 (p = 0.034 and p = 0.018, respectively). Significance: Results indicated the anticancer activity of HNP1-3 which can be used as future chemotherapeutic drugs. Furthermore, leukofilters can be considered as economic source for purifying these peptides.