Immune cell and tumor cell-derived CXCL10 is indicative of immunotherapy response in metastatic melanoma

Abstract

A T cell-inflamed tumor microenvironment is characterized by the accumulation and local activation of CD8+ T cells and Bat3-lineage dendritic cells, which together are associated with clinical response to anti-programmed cell death protein 1 (anti-PD-1)-based immunotherapy. Preclinical models have demonstrated a crucial role for the chemokine CXCL10 in the recruitment of effector CD8+ T cells into the tumor site, and a chemokine gene signature is also seen in T cell-inflamed tumors from patients. However, the cellular source of CXCL10 in human solid tumors is not known. To identify the cellular source of CXCL10 we analyzed 22 pretreatment biopsy samples of melanoma metastases from patients who subsequently underwent checkpoint blockade immunotherapy. We stained for CD45+ and Sox10+ cells with multiparameter immunofluorescence staining, and RNA in situ hybridization technology was used in concert to identify CXCL10 transcripts. The results were correlated with the expression levels of CXCL10 transcripts from bulk RNA sequencing and the best overall response to immune checkpoint inhibition (anti-PD-1 alone or with anti-CTLA-4) in the same patients. We identified CD45+ cells as the major cellular source for CXCL10 in human melanoma metastases, with additional CXCL10 production seen by Sox10+ cells. Up to 90% of CD45+ cells and up to 69% of Sox10+ cells produced CXCL10 transcripts. The CXCL10 staining result was consistent with the level of CXCL10 expression determined by bulk RNA sequencing. The percentages of CD45+ CXCL10+ cells and Sox10+ CXCL10+ cells independently predicted response (p<0.001). The average number of transcripts per cell correlated with the CD45+ cell infiltrate (R=0.37). Immune cells and melanoma cells produce CXCL10 in human melanoma metastases. Intratumoral CXCL10 is a positive prognostic factor for response to immunotherapy, and the RNAscope technique is achievable using paraffin tissue. Strategies that support effector T cell recruitment via induction of CXCL10 should be considered as a mechanism-based intervention to expand immunotherapy efficacy.

Multiplexed imaging mass cytometry of the chemokine milieus in melanoma characterizes features of the response to immunotherapy

“…Chemokines are small, secreted proteins that mediate immune cell trafficking (19)(20)(21) and immune cell recruitment into tumors (22)(23)(24). In particular, the expression of the CXCR3 ligands CXCL9 and CXCL10 in the tumor microenvironment is required for the recruitment of CD8 + T cells into inflamed tumor tissues (25)(26)(27)(28). CD8 + T cells exposed to cognate antigens may also express CCL4 to recruit additional CD8 + T cells via CCR5 (29).…”

Microparticle-delivered Cxcl9 prolongs Braf inhibitor efficacy in melanoma

“…Therefore, we propose that CXCR3 ligands are clinically relevant to targeted therapies, particularly as CXCL9 expression is strongly induced in BRAFi-treated melanoma patients but return to baseline in relapsing patients, mirroring CD8 expression dynamics and the observations in our mouse models. Consistent with this, multiple studies have found that CXCR3 ligands are critical for the action of anti-PD1/PDL1 immune checkpoint therapies (22,23).…”

EZH2 inhibition remodels the inflammatory senescence-associated secretory phenotype to potentiate pancreatic cancer immune surveillance

“…Chemokines CCL7 and CCL8 are also highly induced in senescent PDAC cells following EZH2 inhibition and bind to the same receptor as CCL2 (CCR2), suggesting they could also play a role in NK cell trafficking into PDAC. Other SASP chemokines such as CXCL9/10 that bind to CXCR3 and are associated with T cell recruitment and “hot” TMEs in other cancer settings 53,54,56,63 are necessary for CD8 + T cell recruitment into PDAC following therapy-induced senescence. Remarkably, in our system, combining increased cytotoxic NK and CD8 + T cell trafficking via SASP chemokines with the enhanced immunogenicity of senescent cells is sufficient to potentiate anti-tumor immune surveillance in PDAC even in the absence of immune checkpoint blockade.…”