P0214 Immunomodulatory effect of chitosan nanoparticles carrying Helicobacter pylori neutrophil-activating protein (HP-NAP) for breast cancer treatment

Abstract

<h3>Background</h3> Breast cancer is one of the leading causes of death in women around the world. Conventional treatments use cytotoxic drugs that have high levels of side effects. Novel treatments with low side effects and maximum efficiency are needed. The <i>Helicobacter pylori</i> neutrophil-activating protein (HP-NAP) is a virulence factor that attracts and activates neutrophils, and promotes their endothelial adhesion and the production of oxygen radicals and chemokines. HP-NAP is an immune modulator able to induce the expression of IL-12 and IL-23. In this study, we evaluated preparation of chitosan nanoparticles carrying recombinant HP-NAP for breast cancer treatment. <h3>Methods</h3> Purification of recombinant HP-NAP was performed by Ni–NTA affinity chromatography. Chitosan nanoparticles were produced, and their size and morphology were investigated. A breast cancer cell line (4T1) was treated with different concentrations of recombinant HP-NAP for various lengths of time and cell viability was assessed. <h3>Findings</h3> SDS–PAGE analysis showed the expression of an approximately 20,000 dalton protein. Dynamic light scattering (DLS) confirmed the size and zeta potential of the nanoparticle. 500ng/mL HP-NAP did not have toxic effects on 4T1 cells after 24h, 48h, and 72h. NapA had no direct toxic effects on breast cancer cells; toxicity was observed in vivo. <h3>Interpretation</h3> The HP-NAP-nanoparticle complex has the potential to shift antigen-specific T-cell responses from a predominant Th2 to a polarised Th1 cytotoxic phenotype, characterised by high levels of interferon-γ and TNF-α production. HP-NAP may be a new tool in cancer immunotherapy.