Irradiated Tumor Cells-Derived Exosomes Modulate Macrophage Polarization by Targeting SHP-2 Mediated Metabolic Reprogramming

Abstract

Tumor-associated macrophages (TAMs) constitute a plastic and heterogeneous cell population of the tumor microenvironment (TME) that can regulate tumor proliferation and support resistance to therapy, constituting promising targets for the development of novel anticancer agents. The efficacy of radiotherapy, a mainstay of cancer treatment, can strongly influence TAMs recruitment and phenotype. Our previous results demonstrated that SHP-2 and PD-L1 inhibition combined with radiotherapy enhances systemic antitumor effects in non-small cell lung cancer (NSCLC). Especially, SHP-2 has an important effect on the polarization of TAM in the context of radiotherapy. However, the immune mechanisms of SHP-2 in TAM remain largely unknown, and this leads us to implement this project. Transmission electron microscopy and differential ultracentrifugation were used to verify the existence of exosomes. The bone marrow-derived macrophages (BMDM) and peritoneal macrophages (PM) were derived from C57BL/6 mice for vitro tests. In vivo and in vitro assays were used to identify roles of exosomal miRNA targeting SHP-2. To investigate the regulating function of SHP-2 in TAMs, co-culture experiments, qPCR, Western Blot, Flow Cytometry and Oxygraph-2k were employed. And we also explore tumor growth and tumor environment changes in SHP-2 flox/floxLyz-Cre+/- (CKO) mice. We found that irradiated tumor cells-derived exosomes reprogramed their energy metabolism and polarized primary macrophages to an anti-inflammatory phenotype. Furthermore, SHP-2 in macrophages was a direct target of exosomal miR-138-5p from irradiated tumor cells. In vitro study also demonstrates that miR-138-5p can down-regulate SHP-2 in the BMDMs and PMs. Further research has shown that SHP-2 negatively regulated glycolysis through dephosphorylating Pyruvate kinase M2 (PKM2) at the Tyr105 site. In addition, SHP-2 can inhabit PKM2 translocation to the nucleus by dephosphorylating PKM2 at the Ser37 site. Thus, the SHP099 (a SHP-2 inhibitor) can uptake and utilization of glucose by SHP-2/PKM2(Tyr105) (Ser37)/β-catenin/LDHA/Glut-1 axis, suggesting that SHP099 plays positive roles on glycolysis and M1-polarized. In vivo study showed that SHP-2 flox/floxLyz-Cre+/- (CKO) mice display enhanced control of solid tumor growth, accompanied by increased the proportion of M1-like macrophages. Our study demonstrates that exosomal miR-138-5p from irradiated tumor cells can modulate macrophage polarization by targeting SHP-2. And SHP-2 negatively regulates glycolysis and polarize macrophage to an M2 phenotype by SHP-2/PKM2(Tyr105) (Ser37)/β-catenin/LDHA/Glut-1 axis.