Immunomodulatory effect of HER2/ERBB2 Peptide on THP-1 derived macrophages

Human epidermal growth factor receptor 2 (HER2) is overexpressed in approximately 30% of breast cancers and associated with aggressive behavior and poor prognosis. In addition to its established role in tumor growth and metastasis, HER2 may also influence the tumor microenvironment by modulating immune cells. Macrophages play an important role in tumor development and suppression depending on their phenotype. Due to the critical role of macrophages in cancer progression, understanding how HER2 directly affects macrophage polarization is particularly important. Therefore, this study aims to investigate the direct effect of HER2 on macrophage polarization by assessing its surface marker regulation. THP-1 human monocytic cells were differentiated into macrophages by incubation with phorbol 12-myristate 13-acetate (PMA). The cells, then were treated with different concentrations of HER2. Following treatment, M1 and M2 macrophage markers were analyzed using flow cytometry to determine the effect of HER2 on macrophage polarization. HER2 was shown to promote M1 macrophage polarization, which has pro-inflammatory and anti-tumoral features. This immunomodulator effect of HER2 indicates the its ability of immune modulation, suggesting potential use of HER2 as an adjuvant and providing a basis for future studies.