PROGESTIN-DRIVEN REGULATORY T CELLS PROMOTE AN AGGRESSIVE PHENOTYPE IN TRIPLE NEGATIVE BREAST TUMORS

DALOTTO-MORENO T; MENDEZ-HUERGO S; MOSES F; RABINOVICH GA; SALATINO M

Congreso; Reunión Anual de la Sociedad Argentina de Inmunologia; 2014

The immune system plays key roles in the elimination of mosttumors. Progesterone (Pg) can shape the immune responsefavoring a tolerogenic rather than a pro-inflammatory adaptiveresponse. As hormone supplement therapies have been associatedwith increased frequency of malignant breast neoplasias,we investigated, using the triple negative 4T1 breast tumor, howprogestins can regulate key immune cell populations in the tumormicroenvironment and how progestin-induced immunosuppressioninfluences to tumor progression. Balb/c mice treated with Pg or itssynthetic analog, medroxyprogesterone acetate (MPA), showed anincreased frequency of Foxp3+ regulatory T cells (Tregs) in draininglymph nodes and displayed an impaired antitumor responseevidenced by a decreased production of IL-17 and IFN-γ by CD4+T cells (p