The Journal of Immunology

NC410, a bivalent LAIR-2 construct, remodels collagen in the tumor microenvironment and abrogates neutrophil-driven T cell suppression

Abstract We previously observed that circulating human neutrophils exposed to epithelial ovarian cancer (OC) ascites fluid supernatants (ASC) and malignant effusions from other tumors acquire T cell suppressor function. Collagen motifs ligate LAIR-1, an inhibitory SHP-1-dependent checkpoint broadly expressed on immune cells. We hypothesized that NC410, a bivalent LAIR-2 construct that inhibits LAIR-1-collagen binding, would rescue neutrophil-driven T cell non-responsiveness. NC410 remodeled ASC collagen resulting in neutrophil clustering and reduction in neutrophil-T cell contact, abrogated ASC-induced neutrophil trogocytosis of T cell membranes and rescued stimulated T cell proliferation. Mean ASC pro-collagen-1α levels were >100-fold greater than serum samples. In a single-center retrospective analysis, after adjusting for age, stage and optimal debulking, ASC pro-collagen-1α and serum sLAIR-1 levels were each associated with worse overall survival (OS), and ASC LAIR-2 levels were associated with better OS. Multispectral imaging of high-grade serous ovarian cancer and non-small cell lung cancer showed highly variable LAIR-1 staining in both tumor cell and immune infiltrates. The proportion of collagen-1-positive cells was highest among tumor cells and tumor-infiltrating immune cells versus stromal immune cells, raising the potential role of tumor-associated collagen limiting immune cell infiltration into tumor. Our results support further evaluation of circulating and tumor-associated collagen products and LAIR-1 and LAIR-2 as prognostic biomarkers in advanced OC and as biomarkers for clinical response to NC410 and to other collagen- and LAIR-directed therapies.

HE4 Overexpression by Ovarian Cancer Promotes a Suppressive Tumor Immune Microenvironment and Enhanced Tumor and Macrophage PD-L1 Expression

Abstract Ovarian cancer is a highly fatal malignancy characterized by early chemotherapy responsiveness but the eventual development of resistance. Immune targeting therapies are changing treatment paradigms for numerous cancer types but have had minimal success in ovarian cancer. Through retrospective patient sample analysis, we have determined that high human epididymis protein 4 (HE4) production correlates with multiple markers of immune suppression in ovarian cancer, including lower CD8+ T cell infiltration, higher PD-L1 expression, and an increase in the peripheral monocyte to lymphocyte ratio. To further understand the impact that HE4 has on the immune microenvironment in ovarian cancer, we injected rats with syngeneic HE4 high– and low–expressing cancer cells and analyzed the differences in their tumor and ascites immune milieu. We found that high tumoral HE4 expression promotes an ascites cytokine profile that is rich in myeloid-recruiting and differentiation factors, with an influx of M2 macrophages and increased arginase 1 production. Additionally, CTL activation is significantly reduced in the ascites fluid, and there is a trend toward lower CTL infiltration of the tumor, whereas NK cell recruitment to the ascites and tumor is also reduced. PD-L1 expression by tumor cells and macrophages is increased by HE4 through a novel posttranscriptional mechanism. Our data have identified HE4 as a mediator of tumor-immune suppression in ovarian cancer, highlighting this molecule as a potential therapeutic target for the treatment of this devastating disease.

Ovarian Cancer Ascites Inhibits Transcriptional Activation of NK Cells Partly through CA125

Abstract Malignant ascites is a common clinical problem in ovarian cancer. NK cells are present in the ascites, but their antitumor activity is inhibited. The underlying mechanisms of the inhibition have yet to be fully elucidated. Using an Fcγ receptor–mediated NK cell activation assay, we show that ascites from ovarian cancer patients potently inhibits NK cell activation. Part of the inhibitory activity is mediated by CA125, a mucin 16 fragment shed from ovarian cancer tumors. Moreover, transcriptional analyses by RNA sequencing reveal upregulation of genes involved in multiple metabolic pathways but downregulation of genes involved in cytotoxicity and signaling pathways in NK cells purified from ovarian cancer patient ascites. Transcription of genes involved in cytotoxicity pathways are also downregulated in NK cells from healthy donors after in vitro treatment with ascites or with a CA125-enriched protein fraction. These results show that ascites and CA125 inhibit antitumor activity of NK cells at transcriptional levels by suppressing expression of genes involved in NK cell activation and cytotoxicity. Our findings shed light on the molecular mechanisms by which ascites inhibits the activity of NK cells and suggest possible approaches to reactivate NK cells for ovarian cancer immunotherapy.

Generation of an Inhibitory NK Cell Subset by TGF-β1/IL-15 Polarization

Abstract NK cells have been shown to exhibit inflammatory and immunoregulatory functions in a variety of healthy and diseased settings. In the context of chronic viral infection and cancer, distinct NK cell populations that inhibit adaptive immune responses have been observed. To understand how these cells arise and further characterize their immunosuppressive role, we examined in vitro conditions that could polarize human NK cells into an inhibitory subset. TGF-β1 has been shown to induce regulatory T cells in vitro and in vivo; we therefore investigated if TGF-β1 could also induce immunosuppressive NK-like cells. First, we found that TGF-β1/IL-15, but not IL-15 alone, induced CD103+CD49a+ NK-like cells from peripheral blood NK cells, which expressed markers previously associated with inhibitory CD56+ innate lymphoid cells, including high expression of GITR and CD101. Moreover, supernatant from ascites collected from patients with ovarian carcinoma also induced CD103+CD49a+ NK-like cells in vitro in a TGF-β–dependent manner. Interestingly, TGF-β1/IL-15–induced CD103+CD56+ NK-like cells suppressed autologous CD4+ T cells in vitro by reducing absolute number, proliferation, and expression of activation marker CD25. Collectively, these findings provide new insight into how NK cells may acquire an inhibitory phenotype in TGF-β1–rich environments.

Immune Subtypes and Immune Landscape Analysis of Endometrial Carcinoma

Abstract Some patients with endometrial cancer (EC) suffer from limited survival benefits after immunotherapy, suggesting that there may be a specific pattern associated with immunotherapy. Immune-related genes were extracted from The Cancer Genome Atlas databases. We analyzed the differences among immune subtypes (ISs) in the distribution of the tumor mutational burden, chemotherapy-induced immune response markers, immune checkpoint-related genes, immunotherapy, and chemotherapy. We applied dimensionality reduction and defined the immune landscape of EC. Then, we used the Weighted Gene Co-Expression Network Analysis package to identify the coexpression modules of these immune genes. Finally, hub genes were selected and detected by quantitative PCR and immunohistochemistry. We obtained three ISs. There were differences in the distribution of the tumor mutational burden, chemotherapy-induced immune response markers, and immune checkpoint–related genes among the ISs. Regarding immunotherapy and chemotherapy, the IS2 subtypes were more sensitive to programmed cell death protein 1 inhibitors. In addition, different positions in the immune landscape map exhibited different prognostic characteristics, providing further evidence of the ISs. The IS2 subtypes were significantly positively correlated with yellow module gene list, indicating a good prognosis with high score. SIRPG and SLAMF1 were identified as the final characteristic genes. The quantitative PCR and immunohistochemistry results showed that the expression levels of SIRPG and SLAMF1 were low in human EC tissue. In this study, we identified three reproducible ISs of EC. The immune landscape analysis further revealed the intraclass heterogeneity of the ISs. SIRPG and SLAMF1 were identified to be associated with progression, suggesting that they may be novel immune-related biomarkers of EC.

Glycolysis Induced by METTL14 Is Essential for Macrophage Phagocytosis and Phenotype in Cervical Cancer

Abstract N 6-methyladenosine (m6A) is the most abundant mRNA modification in mammals and it plays a vital role in various biological processes. However, the roles of m6A on cervical cancer tumorigenesis, especially macrophages infiltrated in the tumor microenvironment of cervical cancer, are still unclear. We analyzed the abnormal m6A methylation in cervical cancer, using CaSki and THP-1 cell lines, that might influence macrophage polarization and/or function in the tumor microenvironment. In addition, C57BL/6J and BALB/c nude mice were used for validation in vivo. In this study, m6A methylated RNA immunoprecipitation sequencing analysis revealed the m6A profiles in cervical cancer. Then, we discovered that the high expression of METTL14 (methyltransferase 14, N6-adenosine-methyltransferase subunit) in cervical cancer tissues can promote the proportion of programmed cell death protein 1 (PD-1)–positive tumor-associated macrophages, which have an obstacle to devour tumor cells. Functionally, changes of METTL14 in cervical cancer inhibit the recognition and phagocytosis of macrophages to tumor cells. Mechanistically, the abnormality of METTL14 could target the glycolysis of tumors in vivo and vitro. Moreover, lactate acid produced by tumor glycolysis has an important role in the PD-1 expression of tumor-associated macrophages as a proinflammatory and immunosuppressive mediator. In this study, we revealed the effect of glycolysis regulated by METTL14 on the expression of PD-1 and phagocytosis of macrophages, which showed that METTL14 was a potential therapeutic target for treating advanced human cancers.

The miR-23a∼27a∼24-2 microRNA Cluster Promotes Inflammatory Polarization of Macrophages

Abstract Macrophages are critical for regulating inflammatory responses. Environmental signals polarize macrophages to either a proinflammatory (M1) state or an anti-inflammatory (M2) state. We observed that the microRNA (miRNA) cluster mirn23a, coding for miRs-23a, -27a, and -24-2, regulates mouse macrophage polarization. Gene expression analysis of mirn23a-deficient myeloid progenitors revealed a decrease in TLR and IFN signaling. Mirn23a−/− bone marrow–derived macrophages (BMDMs) have an attenuated response to LPS, demonstrating an anti-inflammatory phenotype in mature cells. In vitro, mirn23a−/− BMDMs have decreased M1 responses and an enhanced M2 responses. Overexpression of mirn23a has the opposite effect, enhancing M1 and inhibiting M2 gene expression. Interestingly, expression of mirn23a miRNAs goes down with inflammatory stimulation and up with anti-inflammatory stimulation, suggesting that its regulation prevents locking macrophages into polarized states. M2 polarization of tumor-associated macrophages (TAMs) correlates with poor outcome for many tumors, so to determine if there was a functional consequence of mirn23a loss modulating immune cell polarization, we assayed syngeneic tumor growth in wild-type and mirn23a−/− mice. Consistent with the increased anti-inflammatory/immunosuppressive phenotype in vitro, mirn23a−/− mice inoculated with syngeneic tumor cells had worse outcomes compared with wild-type mice. Coinjecting tumor cells with mirn23a−/− BMDMs into wild-type mice phenocopied tumor growth in mirn23a−/− mice, supporting a critical role for mirn23a miRNAs in macrophage-mediated tumor immunity. Our data demonstrate that mirn23a regulates M1/M2 polarization and suggests that manipulation of mirn23a miRNA can be used to direct macrophage polarization to drive a desired immune response.

Efficient expansion of tumor-infiltrating lymphocytes from gynecologic cancer

Abstract Tumor-infiltrating lymphocyte (TIL) therapy is a type of adoptive immunotherapy potentially applicable to many types of solid tumors. Although gynecologic malignancies are promising targets for TIL therapy, its objective efficacy has not been established. Current TIL culture typically involves incubation of dissociated samples with high-dose IL-2 (HD-IL2) for weeks to enrich tumor-reactive T cells. While this protocol has been successfully used for melanoma TIL, it has not necessarily been optimized for other cancers. Here we investigated the method of efficiently expanding TILs derived from patients with gynecological cancers. TILs were incubated with HD-IL2 (HD-IL2-TILs) or stimulated with K562 cells expressing anti-CD3 mAb and CD80 (αCD3/CD80-TILs). We found that the αCD3/CD80-TILs showed significantly better proliferation than HD-IL2-TILs. The TIL populations that predominantly expanded upon αCD3/CD80 stimulation expressed high levels of PD-1 and CD28. CD28 co-stimulation was essential to overcome PD-1–mediated signals for growth suppression. We also identified DUSP4 as a negative regulator of TIL proliferation by downregulating ERK phosphorylation. The αCD3/CD80-TILs were reactive to tumor cells as shown by IFN-γ secretion and CD107a expression. Moreover, the αCD3/CD80-TILs were efficiently transduced with a chimeric cytokine receptor that we had previously developed to provide constitutive IL-7 signaling, resulting in superior in vivo persistence and antitumor effects without exogenous cytokine support in mouse models. Collectively, this study shows that direct stimulation of TILs with anti-CD3 mAb and CD28 co-stimulation achieves efficient expansion of tumor-reactive TILs. Genetic engineering of cytokine signaling in TILs may further enhance TIL functions and replace cytokine administration after TIL infusion.