Serum very long-chain fatty acid-containing lipids predict response to immune checkpoint inhibitors in urological cancers Abstract Checkpoint inhibitors (CPI) have significantly changed the therapeutic landscape of oncology. We adopted a non-invasive metabolomic approach to understand immunotherapy response and failure in 28 urological cancer patients. In total, 134 metabolites were quantified in patient sera before the first, second, and third CPI doses. Modeling the association between metabolites and CPI response and patient characteristics revealed that one predictive metabolite class  (n = 9/10) were very long-chain fatty acid-containing lipids (VLCFA-containing lipids). The best predictive performance was achieved through a multivariate model, including age and a centroid of VLCFA-containing lipids prior to first immunotherapy (sensitivity: 0.850, specificity: 0.825, ROC: 0.935). We hypothesize that the association of VLCFA-containing lipids with CPI response is based on enhanced peroxisome signaling in T cells, which results in a switch to fatty acid catabolism. Beyond use as a novel predictive non-invasive biomarker, we envision that nutritional supplementation with VLCFA-containing lipids might serve as an immuno sensitizer.

Pembrolizumab for anaplastic thyroid cancer: a case study Abstract Blockade of the PD-1/PD-L1 pathway with targeted monoclonal antibodies has demonstrated encouraging anti-tumour activity in multiple cancer types. We present the case of a patient with BRAF-negative stage IVC anaplastic thyroid cancer (ATC) treated with the anti-PD-1 monoclonal antibody, pembrolizumab, following radiographic progression on chemoradiation. Blood samples were collected prior to and at four time points during treatment with pembrolizumab. Mass cytometry was used to determine expression of relevant biomarkers by peripheral blood mononuclear cells. Faecal samples were collected at baseline and 4 weeks following treatment initiation; taxonomic profiling using 16S ribosomal RNA (rRNA) gene sequencing was performed. Following treatment, a marked expansion in CD20+ B cell, CD16+ CD56lo NK cell and CD45RO+ CCR7+ central memory CD4+ T-cell populations was observed in the peripheral blood. Proportions of cells expressing the co-receptors TIGIT, OX40 and CD86 also increased during treatment. A high abundance of bacteria of the order Bacteroidales, specifically from the Bacteroidaceae and Rikenellaceae families, was identified in the faecal microbiota. Moreover, the patient’s microbiome was enriched in Clostridiales order members Ruminococcaceae, Veillonellaceae and Lachnospiraceae. Alpha diversity of the gut microbiome was significantly higher following initiation of checkpoint therapy as assessed by the Shannon and Simpson index. Our results suggest that treatment with pembrolizumab promotes expansion of T-, B- and NK cell populations in the peripheral blood at the time of tumour regression and have the potential to be implemented as predictive biomarkers in the context of checkpoint blockade therapy. Larger studies to confirm these findings are warranted.

Predominance of M2 macrophages in gliomas leads to the suppression of local and systemic immunity Abstract Glioblastoma is a highly prevalent and aggressive form of primary brain tumor. It represents approximately 56% of all the newly diagnosed gliomas. Macrophages are one of the major constituents of tumor-infiltrating immune cells in the human gliomas. The role of immunosuppressive macrophages is very well documented in correlation with the poor prognosis of patients suffering from breast, prostate, bladder and cervical cancers. The current study highlights the correlation between the tumor-associated macrophage phenotypes and glioma progression. We observed an increase in the pool of M2 macrophages in high-grade gliomas, as confirmed by their CD68 and CD163 double-positive phenotype. In contrast, less M1 macrophages were noticed in high-grade gliomas, as evidenced by the down-regulation in the expression of CCL3 marker. In addition, we observed that higher gene expression ratio of CD163/CCL3 is associated with glioma progression. The Kaplan–Meier survival plots indicate that glioma patients with lower expression of M2c marker (CD163), and higher expression of M1 marker (CCL3) had better survival. Furthermore, we examined the systemic immune response in the peripheral blood and noted a predominance of M2 macrophages, myeloid-derived suppressor cells and PD-1+ CD4 T cells in glioma patients. Thus, the study indicates a high gene expression ratio of CD163/CCL3 in high-grade gliomas as compared to low-grade gliomas and significantly elevated frequency of M2 macrophages and PD-1+ CD4 T cells in the blood of tumor patients. These parameters could be used as an indicator of the early diagnosis and prognosis of the disease.

Preclinical development of T-cell receptor-engineered T-cell therapy targeting the 5T4 tumor antigen on renal cell carcinoma Abstract 5T4 (trophoblast glycoprotein, TPBG) is a transmembrane tumor antigen expressed on more than 90% of primary renal cell carcinomas (RCC) and a wide range of human carcinomas but not on most somatic adult tissues. The favorable expression pattern has encouraged the development and clinical testing of 5T4-targeted antibody and vaccine therapies. 5T4 also represents a compelling and unexplored target for T-cell receptor (TCR)-engineered T-cell therapy. Our group has previously isolated high-avidity CD8+ T-cell clones specific for an HLA-A2-restricted 5T4 epitope (residues 17–25; 5T4p17). In this report, targeted single-cell RNA sequencing was performed on 5T4p17-specific T-cell clones to sequence the highly variable complementarity-determining region 3 (CDR3) of T-cell receptor α chain (TRA) and β chain (TRB) genes. Full-length TRA and TRB sequences were cloned into lentiviral vectors and transduced into CD8+ T-cells from healthy donors. Redirected effector T-cell function against 5T4p17 was measured by cytotoxicity and cytokine release assays. Seven unique TRA-TRB pairs were identified. All seven TCRs exhibited high expression on CD8+ T-cells with transduction efficiencies from 59 to 89%. TCR-transduced CD8+ T-cells demonstrated redirected cytotoxicity and cytokine release in response to 5T4p17 on target-cells and killed 5T4+/HLA-A2+ kidney-, breast-, and colorectal-tumor cell lines as well as primary RCC tumor cells in vitro. TCR-transduced CD8+ T-cells also detected presentation of 5T4p17 in TAP1/2-deficient T2 target-cells. TCR-transduced T-cells redirected to recognize the 5T4p17 epitope from a broadly shared tumor antigen are of interest for future testing as a cellular immunotherapy strategy for HLA-A2+ subjects with 5T4+ tumors.

Histone deacetylase inhibition promotes intratumoral CD8 + T-cell responses, sensitizing murine breast tumors to anti-PD1 Abstract Histone deacetylase (HDAC) inhibitors impair tumor cell proliferation and alter gene expression. However, the impact of these changes on anti-tumor immunity is poorly understood. Here, we showed that the class I HDAC inhibitor, entinostat (ENT), promoted the expression of immune-modulatory molecules, including MHCII, costimulatory ligands, and chemokines on murine breast tumor cells in vitro and in vivo. ENT also impaired tumor growth in vivo—an effect that was dependent on both CD8+ T cells and IFNγ. Moreover, ENT promoted intratumoral T-cell clonal expansion and enhanced their functional activity. Importantly, ENT sensitized normally unresponsive tumors to the effects of PD1 blockade, predominantly through increases in T-cell proliferation. Our findings suggest that class I HDAC inhibitors impair tumor growth by enhancing the proliferative and functional capacity of CD8+ T cells and by sensitizing tumor cells to T-cell recognition.

PD-1 + TIGIT + CD8 + T cells are associated with pathogenesis and progression of patients with hepatitis B virus-related hepatocellular carcinoma Abstract Hepatitis B virus-associated hepatocellular carcinoma (HBV-HCC) is usually considered an inflammation-related cancer associated with chronic inflammation triggered by exposure to HBV and tumor antigens. T-cell exhaustion is implicated in immunosuppression of chronic infections and tumors. Although immunotherapies that enhance immune responses by targeting programmed cell death-1(PD-1)/PD-L1 are being applied to malignancies, these treatments have shown limited response rates, suggesting that additional inhibitory receptors are also involved in T-cell exhaustion and tumor outcome. Here, we analyzed peripheral blood samples and found that coexpression of PD-1 and T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain (TIGIT) was significantly upregulated on CD4+ and CD8+ T cells from patients with HBV-HCC compared with those from patients with chronic HBV or HBV-liver cirrhosis. Additionally, PD-1+ TIGIT+ CD8+ T-cell populations were elevated in patients with advanced stage and progressed HBV-HCC. Importantly, PD-1+ TIGIT+ CD8+ T-cell populations were negatively correlated with overall survival rate and progression-free survival rates. Moreover, we showed that PD-1+ TIGIT+ CD8+ T cells exhibit features of exhausted T cells, as manifested by excessive activation, high expression of other inhibitory receptors, high susceptibility to apoptosis, decreased capacity for cytokine secretion, and patterns of transcription factor expression consistent with exhaustion. In conclusion, PD-1+ TIGIT+ CD8+ T-cell populations are associated with accelerated disease progression and poor outcomes in HBV-HCC, which might not only have important clinical implications for prognosis but also provide a rationale for new targets in immunotherapy.

Activated hepatic stellate cells regulate MDSC migration through the SDF-1/CXCR4 axis in an orthotopic mouse model of hepatocellular carcinoma Abstract Hepatic stellate cells (HSCs) are important stromal cells and pivotal mediators involved in the pathogenesis and immunosuppression of hepatocellular carcinoma (HCC). The liver has been demonstrated to be a site for accumulation of tumor-induced myeloid-derived suppressor cells (MDSCs). We previously reported that HSCs induced an increase in the number of MDSCs in HCC. However, how MDSCs are recruited in HCC remains largely unclear. In the present study, we found that HSC-conditioned medium (HSC-CM) induced bone marrow-derived cell and splenocyte migration, especially MDSC migration. Using chemokine-neutralizing antibodies and chemokine receptor inhibitors, we found that HSCs promoted MDSC migration through the SDF-1/CXCR4 axis. Subsequently, we used an orthotopic mouse liver tumor model to determine how HSCs mediated MDSC migration to HCC in vivo. The in vivo results indicated that pretreatment of MDSCs with a CXCR4 inhibitor or injection with SDF-1-knocked down HSCs inhibited MDSC migration to the spleen and liver of the tumor-bearing mice. Together, our findings indicate a central role for HSCs in MDSC migration mediated by the SDF-1/CXCR4 axis, thus revealing a potentially effective approach for modulating the tumor microenvironment by targeting HSCs in HCC.

Tumor-associated macrophages expressing galectin-9 identify immunoevasive subtype muscle-invasive bladder cancer with poor prognosis but favorable adjuvant chemotherapeutic response Abstract Purpose Tumor-associated macrophages (TAMs) exist as heterogeneous subsets and have dichotomous roles in cancer-immune evasion. This study aims to assess the clinical effects of Galectin-9+ tumor-associated macrophages (Gal-9+TAMs) in muscle-invasive bladder cancer (MIBC). Experimental design We identified Gal-9+TAMs by immunohistochemistry (IHC) analysis of a tumor microarray (TMA) (n = 141) from the Zhongshan Hospital and by flow cytometric analysis of tumor specimens (n = 20) from the Shanghai Cancer Center. The survival benefit of platinum-based chemotherapy in this subpopulation was evaluated. The effect of the tumor-immune microenvironment with different percentages of Gal-9+TAMs was explored. Results The frequency of Gal-9+TAMs increased with tumor stage and grade. Gal-9+TAMs predicted poor overall survival (OS) and recurrence-free survival (RFS) and were better than Gal-9−TAMs and TAMs to discriminate prognostic groups. In univariate and multivariate Cox regression analyses, patients with high percentages of Gal-9+TAMs showed the prominent survival benefit after receiving adjuvant chemotherapy (ACT). High Gal-9+TAM infiltration correlated with increasing numbers of regulatory T cells (Tregs) and mast cells and decreasing numbers of CD8+T and dendritic cells (DCs). Dense infiltration of Gal-9+TAMs was related to reduced cytotoxic molecules, enhanced immune checkpoints or immunosuppressive cytokines expressed by immune cells, as well as active proliferation of tumor cells. Additionally, the subpopulation accumulated was strongly associated with PD-1+TIM-3+CD8+T cells. Conclusions Gal-9+TAMs predicted OS and RFS and response to ACT in MIBC patients. High Gal-9+TAMs were associated with a pro-tumor immune contexture concomitant with T cell exhaustion.

Regulatory T cells induce CD4 − NKT cell anergy and suppress NKT cell cytotoxic function Abstract Background Due to the strong tumoricidal activities of activated natural killer T (NKT) cells, invariant NKT cell-based immunotherapy has shown promising clinical efficacy. However, suppressive factors, such as regulatory T cells (Tregs), may be obstacles in the use of NKT cell-based cancer immunotherapy for advanced cancer patients. Here, we investigated the suppressive effects of Tregs on NKT cells and the underlying mechanisms with the aim to improve the antitumor activities of NKT cells. Methods Peripheral blood samples were obtained from healthy donors, patients with benign tumors, and patients with head and neck squamous cell carcinoma (HNSCC). NKT cells, induced with α-galactosylceramide (α-GalCer), and monocyte-derived dendritic cells (DCs) were co-cultured with naïve CD4+ T cell-derived Tregs to investigate the mechanism of the Treg suppressive effect on NKT cell cytotoxic function. The functions and phenotypes of NKT cells were evaluated with flow cytometry and cytometric bead array. Results Treg suppression on NKT cell function required cell-to-cell contact and was mediated via impaired DC maturation. NKT cells cultured under Treg-enriched conditions showed a decrease in CD4− NKT cell frequency, which exert strong tumoricidal responsiveness upon α-GalCer stimulation. The same results were observed in HNSCC patients with significantly increased effector Tregs. Conclusion Tregs exert suppressive effects on NKT cell tumoricidal function by inducing more CD4− NKT cell anergy and less CD4+ NKT cell anergy. Both Treg depletion and NKT cell recovery from the anergy state may be important for improving the clinical efficacy of NKT cell-based immunotherapy in patients with advanced cancers.

Identification of prognostic genes in the acute myeloid leukemia immune microenvironment based on TCGA data analysis Abstract Acute myeloid leukemia (AML) is a common and lethal hematopoietic malignancy that is highly dependent on the bone marrow (BM) microenvironment. Infiltrating immune and stromal cells are important components of the BM microenvironment and significantly influence the progression of AML. This study aimed to elucidate the value of immune/stromal cell-associated genes for AML prognosis by integrated bioinformatics analysis. We obtained expression profiles from The Cancer Genome Atlas (TCGA) database and used the ESTIMATE algorithm to calculate immune scores and stromal scores; we then identified differentially expressed genes (DEGs) based on these scores. Overall survival analysis was applied to reveal common DEGs of prognostic value. Subsequently, we conducted a functional enrichment analysis, generated a protein–protein interaction (PPI) network and performed an interrelation analysis of immune system processes, showing that these genes are mainly associated with the immune/inflammatory response. Finally, eight genes (CD163, CYP27A1, KCNA5, PPM1J, FOLR1, IL1R2, MYOF, VSIG2) were verified to be significantly associated with AML prognosis in the Gene Expression Omnibus (GEO) database. In summary, we identified key microenvironment-related genes that affect the outcomes of AML patients and might serve as therapeutic targets.