Macrophage-Derived CXCL9 and CXCL10 Are Required for Antitumor Immune Responses Following Immune Checkpoint Blockade.

Response rates to immune checkpoint blockade (ICB; anti-PD-1/anti-CTLA-4) correlate with the extent of tumor immune infiltrate, but the mechanisms underlying the recruitment of T cells following therapy are poorly characterized. A greater understanding of these processes may see the development of therapeutic interventions that enhance T-cell recruitment and, consequently, improved patient outcomes. We therefore investigated the chemokines essential for immune cell recruitment and subsequent therapeutic efficacy of these immunotherapies. The chemokines upregulated by dual PD-1/CTLA-4 blockade were assessed using NanoString-based analysis with results confirmed at the protein level by flow cytometry and cytometric bead array. Blocking/neutralizing antibodies confirmed the requirement for key chemokines/cytokines and immune effector cells. Results were confirmed in patients treated with immune checkpoint inhibitors using single-cell RNA-sequencing (RNA-seq) and paired survival analyses. The CXCR3 ligands, CXCL9 and CXCL10, were significantly upregulated following dual PD-1/CTLA-4 blockade and both CD8+ T-cell infiltration and therapeutic efficacy were CXCR3 dependent. In both murine models and patients undergoing immunotherapy, macrophages were the predominant source of CXCL9 and their depletion abrogated CD8+ T-cell infiltration and the therapeutic efficacy of dual ICB. Single-cell RNA-seq analysis of patient tumor-infiltrating lymphocytes (TIL) revealed that CXCL9/10/11 was predominantly expressed by macrophages following ICB and we identified a distinct macrophage signature that was associated with positive responses to ICB. These data underline the fundamental importance of macrophage-derived CXCR3 ligands for the therapeutic efficacy of ICB and highlight the potential of manipulating this axis to enhance patient responses.

House IG ，Savas P ，Lai J ，Chen AXY ，Oliver AJ ，Teo ZL ，Todd KL ，Henderson MA ，Giuffrida L ，Petley EV ，Sek K ，Mardiana S ，Gide TN ，Quek C ，Scolyer RA ，Long GV ，Wilmott JS ，Loi S ，Darcy PK ，Beavis PA ... -  《-》

Exercise Training Improves Tumor Control by Increasing CD8(+) T-cell Infiltration via CXCR3 Signaling and Sensitizes Breast Cancer to Immune Checkpoint Blockade.

The mechanisms behind the antitumor effects of exercise training (ExTr) are not fully understood. Using mouse models of established breast cancer, we examined here the causal role of CD8+ T cells in the benefit acquired from ExTr in tumor control, as well as the ability of ExTr to improve immunotherapy responses. We implanted E0771, EMT6, MMTV-PyMT, and MCa-M3C breast cancer cells orthotopically in wild-type or Cxcr3-/- female mice and initiated intensity-controlled ExTr sessions when tumors reached approximately 100 mm3 We characterized the tumor microenvironment (TME) using flow cytometry, transcriptome analysis, proteome array, ELISA, and immunohistochemistry. We used antibodies against CD8+ T cells for cell depletion. Treatment with immune checkpoint blockade (ICB) consisted of anti-PD-1 alone or in combination with anti-CTLA-4. ExTr delayed tumor growth and induced vessel normalization, demonstrated by increased pericyte coverage and perfusion and by decreased hypoxia. ExTr boosted CD8+ T-cell infiltration, with enhanced effector function. CD8+ T-cell depletion prevented the antitumor effect of ExTr. The recruitment of CD8+ T cells and the antitumor effects of ExTr were abrogated in Cxcr3-/- mice, supporting the causal role of the CXCL9/CXCL11-CXCR3 pathway. ExTr also sensitized ICB-refractory breast cancers to treatment. Our results indicate that ExTr can normalize the tumor vasculature, reprogram the immune TME, and enhance the antitumor activity mediated by CD8+ T cells via CXCR3, boosting ICB responses. Our findings and mechanistic insights provide a rationale for the clinical translation of ExTr to improve immunotherapy of breast cancer.

Gomes-Santos IL ，Amoozgar Z ，Kumar AS ，Ho WW ，Roh K ，Talele NP ，Curtis H ，Kawaguchi K ，Jain RK ，Fukumura D ... -  《-》

Cooperation between Constitutive and Inducible Chemokines Enables T Cell Engraftment and Immune Attack in Solid Tumors.

We investigated the role of chemokines in regulating T cell accumulation in solid tumors. CCL5 and CXCL9 overexpression was associated with CD8+ T cell infiltration in solid tumors. T cell infiltration required tumor cell-derived CCL5 and was amplified by IFN-γ-inducible, myeloid cell-secreted CXCL9. CCL5 and CXCL9 coexpression revealed immunoreactive tumors with prolonged survival and response to checkpoint blockade. Loss of CCL5 expression in human tumors was associated with epigenetic silencing through DNA methylation. Reduction of CCL5 expression caused tumor-infiltrating lymphocyte (TIL) desertification, whereas forced CCL5 expression prevented Cxcl9 expression and TILs loss, and attenuated tumor growth in mice through IFN-γ. The cooperation between tumor-derived CCL5 and IFN-γ-inducible CXCR3 ligands secreted by myeloid cells is key for orchestrating T cell infiltration in immunoreactive and immunoresponsive tumors.

Dangaj D ，Bruand M ，Grimm AJ ，Ronet C ，Barras D ，Duttagupta PA ，Lanitis E ，Duraiswamy J ，Tanyi JL ，Benencia F ，Conejo-Garcia J ，Ramay HR ，Montone KT ，Powell DJ Jr ，Gimotty PA ，Facciabene A ，Jackson DG ，Weber JS ，Rodig SJ ，Hodi SF ，Kandalaft LE ，Irving M ，Zhang L ，Foukas P ，Rusakiewicz S ，Delorenzi M ，Coukos G ... -  《-》

CXCR3 Ligands in Cancer and Autoimmunity, Chemoattraction of Effector T Cells, and Beyond.

CXCR3 is a chemokine receptor with three ligands; CXCL9, CXCL10, and CXCL11. CXCL11 binds CXCR3 with a higher affinity than the other ligands leading to receptor internalization. Long ago we reported that one of these chemokines, CXCL10, not only attracts CXCR3+ CD4+ and CD8+ effector T cells to sites of inflammation, but also direct their polarization into highly potent effector T cells. Later we showed that CXCL11 directs the linage development of T-regulatory-1 cells (Tr1). We also observed that CXCL11 and CXCL10 induce different signaling cascades via CXCR3. Collectively this suggests that CXCR3 ligands differentially regulate the biological function of T cells via biased signaling. It is generally accepted that tumor cells evolved to express several chemokine receptors and secrete their ligands. Vast majority of these chemokines support tumor growth by different mechanisms that are discussed. We suggest that CXCL10 and possibly CXCL9 differ from other chemokines by their ability to restrain tumor growth and enhance anti-tumor immunity. Along with this an accumulating number of studies showed in various human cancers a clear association between poor prognosis and low expression of CXCL10 at tumor sites, and vice versa. Finally, we discuss the possibility that CXCL9 and CXCL10 may differ in their biological function via biased signaling and its possible relevance to cancer immunotherapy. The current mini review focuses on exploring the role of CXCR3 ligands in directing the biological properties of CD4+ and CD8+ T cells in the context of cancer and autoimmunity. We believe that the combined role of these chemokines in attracting T cells and also directing their biological properties makes them key drivers of immune function.

Karin N 《-》

Intratumoral Activity of the CXCR3 Chemokine System Is Required for the Efficacy of Anti-PD-1 Therapy.

Despite compelling rates of durable clinical responses to programmed cell death-1 (PD-1) blockade, advances are needed to extend these benefits to resistant tumors. We found that tumor-bearing mice deficient in the chemokine receptor CXCR3 responded poorly to anti-PD-1 treatment. CXCR3 and its ligand CXCL9 were critical for a productive CD8+ T cell response in tumor-bearing mice treated with anti-PD-1 but were not required for the infiltration of CD8+ T cells into tumors. The anti-PD-1-induced anti-tumor response was facilitated by CXCL9 production from intratumoral CD103+ dendritic cells, suggesting that CXCR3 facilitates dendritic cell-T cell interactions within the tumor microenvironment. CXCR3 ligands in murine tumors and in plasma of melanoma patients were an indicator of clinical response to anti-PD-1, and their induction in non-responsive murine tumors promoted responsiveness to anti-PD-1. Our data suggest that the CXCR3 chemokine system is a biomarker for sensitivity to PD-1 blockade and that augmenting the intratumoral function of this chemokine system could improve clinical outcomes.

Chow MT ，Ozga AJ ，Servis RL ，Frederick DT ，Lo JA ，Fisher DE ，Freeman GJ ，Boland GM ，Luster AD ... -  《-》