MDR1-EXPRESSING CD4 T CELLS WITH TH1.17 FEATURES RESIST TO NEOADJUVANT CHEMOTHERAPY AND ARE ASSOCIATED WITH BREAST CANCER CLINICAL RESPONSE.

Background: Multidrug resistance-1 (MDR1) transporter limits the intracellular accumulation of chemotherapies (paclitaxel, anthracyclines) used in breast cancer (BC) treatment. In addition to tumor cells, MDR1 is expressed on immune cell subsets in which it confers chemoresistance. Among human T cells, MDR1 is expressed by most CD8 T cells, and a subset of CD4 T helper (Th) cells.

Recruitment and Expansion of Tregs Cells in the Tumor Environment-How to Target Them?

Regulatory T cells (Tregs) are present in a large majority of solid tumors and are mainly associated with a poor prognosis, as their major function is to inhibit the antitumor immune response contributing to immunosuppression. In this review, we will investigate the mechanisms involved in the recruitment, amplification and stability of Tregs in the tumor microenvironment (TME). We will also review the strategies currently developed to inhibit Tregs' deleterious impact in the TME by either inhibiting their recruitment, blocking their expansion, favoring their plastic transformation into other CD4 T-cell subsets, blocking their suppressive function or depleting them specifically in the TME to avoid severe deleterious effects associated with Treg neutralization/depletion in the periphery and normal tissues.

Methotrexate Restores CD73 Expression on Th1.17 in Rheumatoid Arthritis and Psoriatic Arthritis Patients and May Contribute to Its Anti-Inflammatory Effect through Ado Production.

Objectives: Th1.17 are highly polyfunctional, potentially harmful CD4 effector T cells (Teff) through IFN-γ and IL-17A coproduction. Th1.

MDR1 in immunity: friend or foe?

MDR1 is an ATP-dependent transmembrane transporter primarily studied for its role in the detoxification of tissues and for its implication in resistance of tumor cells to chemotherapy treatment. Several studies also report on its expression on immune cells where it plays a protective role from xenobiotics and toxins. This review provides an overview of what is known on MDR1 expression in immune cells in human, and its implications in different pathologies and their treatment options.