TIE-2 Signaling Activation by Angiopoietin 2 On Myeloid-Derived Suppressor Cells Promotes Melanoma-Specific T-cell Inhibition

oleh: Amélie Marguier, Caroline Laheurte, Caroline Laheurte, Benoît Lecoester, Marine Malfroy, Laura Boullerot, Laura Boullerot, Adeline Renaudin, Evan Seffar, Abhishek Kumar, Charlée Nardin, Charlée Nardin, François Aubin, François Aubin, Olivier Adotevi, Olivier Adotevi, Olivier Adotevi

Format: Article
Diterbitkan: Frontiers Media S.A. 2022-07-01

Deskripsi

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous group of immune suppressive cells detected in several human cancers. In this study, we investigated the features and immune suppressive function of a novel subset of monocytic MDSC overexpressing TIE-2 (TIE-2+ M-MDSC), the receptor for the pro-angiogenic factor angiopoietin 2 (ANGPT2). We showed that patients with melanoma exhibited a higher circulating rate of TIE-2+ M-MDSCs, especially in advanced stages, as compared to healthy donors. The distribution of the TIE-2+ M-MDSC rate toward the melanoma stage correlated with the serum level of ANGPT2. TIE-2+ M-MDSC from melanoma patients overexpressed immune suppressive molecules such as PD-L1, CD73, TGF-β, and IL-10, suggesting a highly immunosuppressive phenotype. The exposition of these cells to ANGPT2 increased the expression of most of these molecules, mainly Arginase 1. Hence, we observed a profound impairment of melanoma-specific T-cell responses in patients harboring high levels of TIE-2+ M-MDSC along with ANGPT2. This was confirmed by in vitro experiments indicating that the addition of ANGPT2 increased the ability of TIE-2+ M-MDSC to suppress antitumor T-cell function. Furthermore, by using TIE-2 kinase-specific inhibitors such as regorafenib or rebastinib, we demonstrated that an active TIE-2 signaling was required for optimal suppressive activity of these cells after ANGPT2 exposition. Collectively, these results support that TIE-2+ M-MDSC/ANGPT2 axis represents a potential immune escape mechanism in melanoma.