Adiponectin‐expressing Treg‐containing T cell fraction inhibits tumor growth in orthotopically implanted triple‐negative breast cancer

BACKGROUND: In our previous study, we identified a population of adiponectin expressing regulatory T cells (Tregs) residing within thymic nurse cell complexes, which were capable of inhibiting the development of breast cancer in vitro. Triple‐negative breast cancer (TNBC) with no proper treatment at present is characterized by the absence of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor‐2. In this study, we aimed to investigate the potential of a cultured T cell fraction comprising adiponectin‐expressing Tregs, referred to as A‐TregTF (adiponectin‐expressing Treg‐containing T cell fraction), in inhibiting the progression of TNBC in vivo. METHODS: The efficacy of a spontaneously expanding T cell fraction comprising adiponectin‐expressing Treg in inhibiting tumor growth was analyzed in a murine orthotopic 4 T1‐Luc TNBC model. RESULTS: The treatment with T cell fraction containing adiponectin‐expressing Tregs significantly inhibited the growth and metastasis of orthotopically transplanted 4 T1‐Luc tumor cells. Histopathological examination further revealed that the adiponectin‐expressing Tregs infiltrated the tumor tissue via a cell‐in‐cell mechanism and were found to be specifically localized around the necrotic areas. CONCLUSIONS: Based on our findings, the T cell fraction comprising adiponectin‐expressing Tregs, represents a potential candidate for adoptive cell therapy against TNBC.