CD8+ CD73+ T cells in the tumor microenvironment of head and neck cancer patients are linked to diminished T cell infiltration and activation in tumor tissue

Single-Cell Phenotyping of CD73 Expression Reveals the Diversity of the Tumor Immune Microenvironment and Reflects the Prognosis of Bladder Cancer

The cutting edge of cancer immunotherapy extends to ecto-5'-nucleotidase (CD73), a cell membrane enzyme that targets the metabolism of extracellular adenosine. We herein focused on the expression of CD73 to clarify the state of CD73 positivity in cancer immunity and tumor microenvironment, thereby revealing a new survival predictor for patients with bladder cancer (BCa). We used clinical tissue microarrays of human BCa and simultaneously performed the fluorescent staining of cell type-specific markers (CD3, CD8, Foxp3, programmed cell death protein 1, and programmed death-ligand 1 [PD-L1]) and CD73 together with DAPI for nuclear staining. In total, 156 participants were included. Multiplexed cellular imaging revealed a unique interaction between CD73 expression and CD8⁺ cytotoxic T cells (CTLs) and Foxp3⁺ regulatory T (Treg) cells in human BCa, showing the high infiltration of CD8⁺CD73⁺ CTLs and Foxp3⁺CD73⁺ Treg cells in tumors to be associated with tumorigenesis and poor prognosis in BCa. Interestingly, from a biomarker perspective, the high infiltration of CD73⁺ Treg cells in tumors was identified as an independent risk factor for overall survival in addition to clinicopathologic features. Regarding the relationship between immune checkpoint molecules and CD73 expression, both CD73⁺ CTLs and CD73⁺ Treg cells tended to coexpress programmed cell death protein 1 as tumor invasiveness and nuclear grade increased. Additionally, they may occupy a spatial niche located distantly from PD-L1⁺ cells in tumors to interfere less with the cancerous effects of PD-L1⁺ cells. In conclusion, the present results on the status of CD73 in cancer immunity suggest that CD73 expression on specific T-cell types has a negative immunoregulatory function. These findings may provide further insights into the immunobiological landscape of BCa, which may be translationally linked to improvements in future immunotherapy practice.

Integrated multi-omics analysis identifies CD73 as a prognostic biomarker and immunotherapy response predictor in head and neck squamous cell carcinoma

BACKGROUND

Advances in tumor immunotherapy have been developed for patients with advanced recurrent or metastatic (R/M) HNSCC. However, the response of most HNSCC patients to immune checkpoint inhibitors (ICI) remains unsatisfactory. CD73 is a promising target for tumor immunotherapy, but its role in HNSCC remains insufficient. In this study, we aim to explore the function of CD73 in HNSCC.

METHODS

Transcriptomic and clinical data of TCGA-HNSC were downloaded from UCSC Xena for analysis of CD73 mRNA expression and prognosis. Immunohistochemical assay were performed to validate the expression of CD73 in tumor tissues and its relationship with CD8+ T cells. GSEA analysis was performed with the "clusterProfiler" R package. Immune infiltration analysis was calculated with ESTIMATE, CIBERSORT and MCP-counter algorithms. Single-cell transcriptomic data was originated from GSE103322. Cell clustering, annotation and CD73 expression were from the TISCH database. Correlation data between CD73 and tumor signatures were obtained from the CancerSEA database. Somatic mutation data were obtained from TCGA-HNSC and analyzed by "maftools" R package. Immune efficacy prediction was performed using TIDE algorithm and validated with the IMvigor210 cohort.

RESULTS

Compared with normal tissues, both mRNA and protein expressions of CD73 were elevated in tumor tissues (P = 9.7×10-10, P = 7.6×10-5, respectively). Kaplan-Meier analysis revealed that patients with high expression of CD73 had worse overall survival (log-rank P = 0.0094), and CD73 could be used as a diagnostic factor for HNSCC (AUC = 0.778). Both bulk RNA-seq and single-cell RNA-seq analysis showed that high CD73 expression can promote EMT and metastasis, samples with high CD73 expression had reduced CD8+ T cells. Furthermore, it was found that CD73-high group was more prone to have mutations in TP53, HRAS and CDKN2A, and were negatively correlated with TMB (P = 0.0055) and MSI (P = 0.00034). Mutational signature analysis found that CD73 was associated with APOBEC signature. Immunotherapy efficacy analysis showed that CD73-high group was less sensitive to immune efficacy.

CONCLUSIONS

Our results demonstrate that CD73 has an inhibitory effect on the tumor microenvironment, and is more likely to be unresponsive to ICI therapy. Collectively, targeting CD73 may provide new insights for tumor targeted therapy and/or immunotherapy.

Tumor-Induced T Cell Polarization by Schwann Cells

Nerve-cancer crosstalk resulting in either tumor neurogenesis or intratumoral neurodegeneration is critically controlled by Schwann cells, the principal glial cells of the peripheral nervous system. Though the direct stimulating effect of Schwann cells on malignant cell proliferation, motility, epithelial-mesenchymal transition, and the formation of metastases have been intensively investigated, the ability of Schwann cells to affect the effector and regulatory immune cells in the tumor environment is significantly less studied. Here, we demonstrated that tumor cells could stimulate Schwann cells to produce high levels of prostaglandin E, which could be blocked by COX-2 inhibitors. This effect was mediated by tumor-derived TGF-β as neutralization of this cytokine in the tumor-conditioned medium completely blocked the inducible prostaglandin E production by Schwann cells. Similar protective effects were also induced by the Schwann cell pretreatment with TGF-βR1/ALK4/5/7 and MAPK/ERK kinase inhibitors of the canonical and non-canonical TGF-β signaling pathways, respectively. Furthermore, prostaglandin E derived from tumor-activated Schwann cells blocked the proliferation of CD3/CD28-activated T cells and upregulated the expression of CD73 and PD-1 on both CD4+ and CD8+ T cells, suggesting T cell polarization to the exhausted phenotype. This new pathway of tumor-induced T cell inhibition via the activation of neuroglial cells represents new evidence of the importance of nerve-cancer crosstalk in controlling tumor development and progression. A better understanding of the tumor-neuro-immune axis supports the development of efficient targets for harnessing this axis and improving the efficacy of cancer therapy.

High Dimensional Immune Profiling of Smoldering Multiple Myeloma Distinguishes Distinct Tumor Microenvironments

BACKGROUND

Multiple myeloma (MM) is a malignancy of plasma cells that arises from premalignant Monoclonal Gammopathy of Undetermined Significance (MGUS) and often progresses through an asymptomatic Smoldering (SMM) phase. Understanding the interactions between abnormal clonal plasma cells and the tumor microenvironment (TME) in the early disease states (MGUS, SMM) may inform risk assessment and therapy.

PATIENTS AND METHODS

We performed high dimensional immunologic analysis of bone marrow specimens from 73 subjects with SMM by mass cytometry and T cell receptor sequencing of CD138-depleted bone marrow (BM) mononuclear cells, and proteomics and seromic profiling of BM plasma. Analysis of individual assay data identified self-organizing subgroups of SMM patients. We then applied novel bioinformatic methods to integrate data from pairs, trios, and quartets of assays.

RESULTS

Mass cytometry, TCRSeq and proteomics identified three taxa (sing. taxon) of subjects that shared common characteristics across all three assays. Differential levels of BM plasma pleiotropin (PTN) and BM T cells and their productive clonality emerged as strong distinguishing factors among these taxa.

CONCLUSION

These results suggest that the continuum from MGUS to MM does not consist of a single pathway in the TME, and that complex interactions between myeloma cells and the TME may ultimately determine progression and inform clinical management.

CD39 - A bright target for cancer immunotherapy

The ATP-adenosine pathway functions as a key modulator of innate and adaptive immunity within the tumor microenvironment, and cancer immune evasion largely involves the generation of high amounts of immunosuppressive extracellular adenosine (eADO). Consequently, inhibition of eADO-generating enzymes and/or eADO receptors can effectively restore the antitumor immunity of multiple immune cells. With several clinical strategies currently being explored to modulating the eADO pathway in patients with cancer, recent clinical data with antagonists targeting CD73 and A_2A receptor have demonstrated a promising therapeutic potential in cancer. Recent findings reveal that the ectonucleotidase CD39, the limiting enzyme been viewed as "immunological switch", converts ATP-driven pro-inflammatory milieu to an anti-inflammatory state mediated by adenosine. Owing to its superior feature of CD39 antagonism that rely not only on preventing the accumulation of adenosine but also on the stabilization of extracellular ATP to restore antitumor immunity, several inhibitors and clinical trials based on CD39 are being evaluated. Consequently, there is currently a focus on understanding the role of CD39 in governing immunity and how therapeutic strategies targeting this pathway alter the antitumor potential. We herein review the impact of CD39 on tumor microenvironment with a focus on treatment preference. Additionally, we also discuss the implication for rational combination therapies, molecular regulation, as well as potential limitations.