Potential activity of adiponectin-expressing regulatory T cells against triple-negative breast cancer cells through the cell-in-cell phenomenon.

BACKGROUND: A population of regulatory T cells (Treg), which reside within thymic nurse cell complexes, express adiponectin and abrogate breast cancer development in transgenic mice. In this study, we examined whether adiponectin-expressing Treg could impair triple-negative breast cancer, which is defined by a lack of estrogen receptors, progesterone receptors, and human epidermal growth factor receptor-2. METHODS: CD4- and CD25-positive cells were sorted from cultured T lymphocytes of a previously characterized experimental thymic tumor model composed of thymic nurse cells and abundant lymphoid stroma. These sorted cells were examined for FOXP3 and adiponectin immunoreactivity and subsequently exposed to triple-negative breast cancer MDA-MB-157 and -231 cells. RESULTS: Adiponectin-expressing Treg were obtained by CD4- and CD25-positive sorting and cell death was induced in triple-negative breast cancer cells through the cell-in-cell phenomenon. CONCLUSIONS: Adiponectin-expressing Treg may be candidates for adoptive cell therapy against triple-negative breast cancer.