Downregulation of TCF7 and LEF1 is a key determinant of tumor-infiltrating regulatory T-cell function.

Forkhead box P3 (Foxp3)-expressing regulatory T (Treg) cells play essential roles in immune homeostasis but also contribute to establish a favorable environment for tumor growth by suppressing anti-tumor immune responses. It is thus necessary to specifically target tumor-infiltrating Treg cells to minimize effects on immune homeostasis in cancer immunotherapy. However, molecular features that distinguish tumor-infiltrating Treg cells from those in secondary lymphoid organs remain unknown. Here we characterize distinct features of tumor-infiltrating Treg cells by global analyses of the transcriptome and chromatin landscape. They exhibited activated phenotypes with enhanced Foxp3-dependent transcriptional regulation, yet being distinct from activated Treg cells in secondary lymphoid organs. Such differences may be attributed to the extensive clonal expansion of tumor-infiltrating Treg cells. Moreover, we found that TCF7 and LEF1 were specifically downregulated in tumor-infiltrating Treg cells both in mice and humans. These factors and Foxp3 co-occupied Treg suppressive function-related gene loci in secondary lymphoid organ Treg cells, whereas the absence of TCF7 and LEF1 accompanied altered gene expression and chromatin status at these gene loci in tumor-infiltrating Treg cells. Functionally, overexpression of TCF7 and LEF1 in Treg cells inhibited the enhancement of Treg suppressive function upon activation. Our results thus show the downregulation of TCF7 and LEF1 as markers of highly suppressive Treg cells in tumors and suggest that their absence controls the augmentation of Treg suppressive function in tumors. These molecules may be potential targets for novel cancer immunotherapy with minimum effects on immune homeostasis.

Immunotherapy Targeting CCR8+ Regulatory T Cells Induces Antitumor Effects via Dramatic Changes to the Intratumor CD8+ T Cell Profile.

Regulatory T cells (Tregs) contribute to the formation of a tumor-immunosuppressive microenvironment. CCR8 is reportedly selectively expressed in tumor Tregs, and an anti-CCR8 Ab can exert potent antitumor effects by eliminating intratumor Tregs in murine tumor models. In this study, we analyzed changes to intratumor immunity after anti-CCR8 Ab administration, especially in CD8+ T cells, which are involved in cancer cell killing, using the CT26 colorectal carcinoma mouse model. Immunophenotyping of tumor-infiltrating cells by mass cytometry after Ab administration on day 5 of tumor inoculation revealed that CD8+ T cell subsets were dramatically altered in the CCR8 Ab-treated group, with an increase in naive cells and nonexhausted effector cells and a decrease in exhausted cells with high expression levels of TOX. These results were corroborated with flow cytometry analysis. Delayed administration of the anti-CCR8 Ab on day 9 or 12, when the amount of CCR8+ Tregs and CD8+ T cell exhaustion were more progressed, also resulted in a decrease in exhausted CD8+ T cells, leading to tumor regression. Finally, we confirmed that high CCR8+ Treg infiltration was associated with high TOX expression in CD8+ T cells in human cancer patients. In conclusion, administration of an anti-CCR8 Ab can dramatically alter the activation and exhaustion state of intratumor CD8+ T cells, resulting in strong antitumor effects. In cancer patients with an advanced tumor-immunosuppressive environment, CD8+ T cell exhaustion has progressed along with CCR8+ Treg induction. Therefore, targeted depletion of CCR8+ Tregs is expected to be effective in these patients.

CCR8-targeted specific depletion of clonally expanded Treg cells in tumor tissues evokes potent tumor immunity with long-lasting memory.

Foxp3-expressing CD25+CD4+ regulatory T cells (Tregs) are abundant in tumor tissues. Here, hypothesizing that tumor Tregs would clonally expand after they are activated by tumor-associated antigens to suppress antitumor immune responses, we performed single-cell analysis on tumor Tregs to characterize them by T cell receptor clonotype and gene-expression profiles. We found that multiclonal Tregs present in tumor tissues predominantly expressed the chemokine receptor CCR8. In mice and humans, CCR8+ Tregs constituted 30 to 80% of tumor Tregs in various cancers and less than 10% of Tregs in other tissues, whereas most tumor-infiltrating conventional T cells (Tconvs) were CCR8- CCR8+ tumor Tregs were highly differentiated and functionally stable. Administration of cell-depleting anti-CCR8 monoclonal antibodies (mAbs) indeed selectively eliminated multiclonal tumor Tregs, leading to cure of established tumors in mice. The treatment resulted in the expansion of CD8+ effector Tconvs, including tumor antigen-specific ones, that were more activated and less exhausted than those induced by PD-1 immune checkpoint blockade. Anti-CCR8 mAb treatment also evoked strong secondary immune responses against the same tumor cell line inoculated several months after tumor eradication, indicating that elimination of tumor-reactive multiclonal Tregs was sufficient to induce memory-type tumor-specific effector Tconvs. Despite induction of such potent tumor immunity, anti-CCR8 mAb treatment elicited minimal autoimmunity in mice, contrasting with systemic Treg depletion, which eradicated tumors but induced severe autoimmune disease. Thus, specific removal of clonally expanding Tregs in tumor tissues for a limited period by cell-depleting anti-CCR8 mAb treatment can generate potent tumor immunity with long-lasting memory and without deleterious autoimmunity.

Serum NY-ESO-1 antibody as a predictive biomarker for postoperative recurrence of gastric cancer: a multicenter prospective observational study.

BACKGROUND: No reliable marker has been identified to predict postoperative recurrence of gastric cancer. We designed a clinical trial to investigate the utility of serum NY-ESO-1 antibody responses as a predictive marker for postoperative recurrence in gastric cancer. METHODS: A multicenter prospective study was conducted between 2012 and 2021. Patients with resectable cT3-4 gastric cancer were included. Postoperative NY-ESO-1 and p53 antibody responses were serially evaluated every 3 months for 1 year in patients with positive preoperative antibody responses. The recurrence rate was assessed by the positivity of antibody responses at 3 and 12 months postoperatively. RESULTS: Among 1001 patients, preoperative NY-ESO-1 and p53 antibody responses were positive in 12.6% and 18.1% of patients, respectively. NY-ESO-1 antibody responses became negative postoperatively in non-recurrent patients (negativity rates; 45% and 78% at 3 and 12 months, respectively), but remained positive in recurrent patients (negativity rates; 9% and 8%, respectively). p53 antibody responses remained positive in non-recurrent patients. In multivariate analysis, NY-ESO-1 antibody positivity at 3 months (P < 0.03) and 12 months (P < 0.001) were independent prognostic factors for a shorter recurrence-free interval. CONCLUSIONS: Serum NY-ESO-1 antibodies may be a useful predictive marker for postoperative recurrence in gastric cancer. CLINICAL TRIAL REGISTRATION: UMIN000007925.

In situ analysis of CCR8+ regulatory T cells in lung cancer: suppression of GzmB+ CD8+ T cells and prognostic marker implications.

BACKGROUND: CCR8-expressing regulatory T cells (Tregs) are selectively localized within tumors and have gained attention as potent suppressors of anti-tumor immunity. This study focused on CCR8+ Tregs and their interaction with CD8+ T cells in the tumor microenvironment of human lung cancer. We evaluated their spatial distribution impact on CD8+ T cell effector function, specifically granzyme B (GzmB) expression, and clinical outcomes. METHODS: A total of 81 patients with lung squamous cell carcinoma (LSCC) who underwent radical surgical resection without preoperative treatment were enrolled. Histological analyses were performed, utilizing an automated image analysis system for double-stained immunohistochemistry assays of CCR8/Foxp3 and GzmB/CD8. We investigated the association of CCR8+ Tregs and GzmB+ CD8+ T cells in tumor tissues and further evaluated the prognostic impact of their distribution profiles. RESULTS: Histological evaluation using the region of interest (ROI) protocol showed that GzmB expression levels in CD8+ T cells were decreased in areas with high infiltration of CCR8+ Tregs, suggesting a suppressive effect of CCR8+ Tregs on T cell cytotoxicity in the local tumor microenvironment. Analysis of the association with clinical outcomes showed that patients with more CCR8+ Tregs and lower GzmB expression, represented by a low GzmB/CCR8 ratio, had worse progression-free survival. CONCLUSIONS: Our data suggest that local CCR8+ Treg accumulation is associated with reduced CD8+ T cell cytotoxic activity and poor prognosis in LSCC patients, highlighting the biological role and clinical significance of CCR8+ Tregs in the tumor microenvironment. The GzmB/CCR8 ratio may be a useful prognostic factor for future clinical applications in LSCC.

Density and maturity of peritumoral tertiary lymphoid structures in oesophageal squamous cell carcinoma predicts patient survival and response to immune checkpoint inhibitors.

BACKGROUND: Tertiary lymphoid structures (TLSs) are ectopic lymphoid aggregates in non-lymphoid tissues, which are associated with improved prognosis in some cancer types. This study aimed to investigate the clinical significance of TLSs in oesophageal cancer (EC). METHODS: In a series of 316 EC surgical specimens from two different institutes, we evaluated the density and maturity of peritumoral TLSs using haematoxylin/eosin, immunohistochemistry, and multiplex immunofluorescence staining. We analysed the association between TLSs and clinicopathological parameters. The clinical significance of TLSs was further evaluated in a different cohort of 34 patients with recurrent EC treated with anti-PD-1 antibody. RESULTS: Tumours with high TLS density predominantly consisted of matured TLSs. High TLS density was significantly associated with less advanced tumour stage, absence of lymphatic/vascular invasion, better serum nutrition parameters (neutrophils count, albumin, neutrophil-to-lymphocyte ratio, and prognostic nutritional index), and prolonged survival. This survival trend was more remarkable in cases with matured TLSs, which represented an increased population of CD138+ plasma cells. In the second EC cohort, TLS density predicted the clinical response to anti-PD-1 antibody and patient survival. CONCLUSION: The density and maturity of peritumoral TLSs are useful parameters for predicting long-term survival and response to anti-PD-1 antibody treatment in EC patients.

The tissue-resident marker CD103 on peripheral blood T cells predicts responses to anti-PD-1 therapy in gastric cancer.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment. Since clinical benefits are limited to a subset of patients, we aimed to identify peripheral blood biomarkers that predict the efficacy of the anti-programmed cell death protein 1 (PD-1) antibody (nivolumab) in patients with gastric cancer. METHODS: We collected peripheral blood samples from gastric cancer patients (n = 29) before and after treatment with nivolumab and investigated the relationship between the frequency of surface or intracellular markers among nivolumab-binding PD-1+CD8+ T cells and treatment responses using multicolor flow cytometry. The tumors, lymph nodes, and peripheral blood of gastric cancer patients who underwent gastrectomy following nivolumab treatment were collected, and nivolumab-binding PD-1+CD8+ T cells in these tissue samples were characterized. RESULTS: Patients with a high frequency of CD103 among PD-1+CD8+ T cells in peripheral blood 2 weeks after the start of treatment had significantly better progression-free survival than the low group (P = 0.032). This CD103+PD-1+CD8+ T cell population mainly consisted of central memory T cells, showing the high expression of Ki-67 and few cytotoxic granules. In contrast, effector memory T cells were more frequently observed among CD103+PD-1+CD8+ T cells in tumors, which implied a change in the differentiated status of central memory T cells in lymph nodes and peripheral blood to effector memory T cells in tumors during the treatment with ICIs. CONCLUSIONS: A high frequency of CD103 among PD-1+CD8+ T cells 2 weeks after nivolumab treatment in patients with advanced gastric cancer may be a useful biomarker for predicting the efficacy of anti-PD-1 therapy.

Tumor endothelial cell-induced CD8+ T-cell exhaustion via GPNMB in hepatocellular carcinoma.

Tumor endothelial cells (TECs) promote tumor angiogenesis and regulate cytotoxic T cells in the tumor microenvironment. However, the roles of TECs for tumor-infiltrating T-cell in hepatocellular carcinoma (HCC) is still unknown. Here, we aimed to investigate how TECs influenced tumor growth and immune responses of HCC focusing on CD8+ T-cell infiltration and exhaustion. First, TECs were isolated from subcutaneous HCC tumors with murine HCC cell lines (BNL-T) with magnetic selection of CD31+ cells, and normal endothelial cells (NECs) were isolated from normal liver. Second, immunocompetent mice were injected with BNL-T alone, BNL-T + NECs, or BNL-T + TECs for tumor formation, and the functions and exhaustion of tumor-infiltrating CD8+ T cells were evaluated. The mice injected with BNL-T + TEC showed rapid tumorigenesis and a decrease in the number of infiltrating CD8+ T cells. In addition, the percentage of CD8+ T-cell exhaustion was significantly higher in tumors from the administration of BNL-T + TEC. Third, the next-generation sequencing on TECs was performed to identify mRNAs that might be a novel treatment target. The molecule of glycoprotein nonmetastatic melanoma protein B (GPNMB) was identified and the functions of GPNMB was analyzed by silencing of GPNMB expression using small interfering RNAs. The silencing of GPNMB expression in TECs induced the suppression of tumor growth and T-cell exhaustion. In conclusion, TECs induced tumor-infiltrating T-cell exhaustion via GPNMB expression and GPNMB might be a novel therapeutic target in HCC.

Circulating extracellular vesicles carrying Firmicutes reflective of the local immune status may predict clinical response to pembrolizumab in urothelial carcinoma patients.

Bacterial flora has clinical significance for the host. The metabolic environment created by this flora influences immunotherapy in urothelial carcinoma. However, there are no reports on the clinical significance of bacterial flora in the host bloodstream. We aimed to clarify the correlation between extracellular vesicle (EV)-derived blood microflora information and tumor immunological status in urothelial carcinoma (UC) patients. Serum samples were collected from 20 healthy donors, 50 patients with localized UC, and 31 patients with metastatic UC (mUC) who had undergone pembrolizumab treatment. Bacterial DNA in EVs was extracted from each sample. Metagenomic sequencing was performed after amplification of the V1-V2 region of the bacterial 16S rRNA gene. Using the matched tumor tissue and serum samples, we revealed that the smaller amount of peripheral EVs carrying Firmicutes DNA was significantly correlated with the higher number of infiltrating T cells within tumor tissues (CD3; p = 0.015, CD4; p = 0.039, CD8; p = 0.0084) and the higher expression of activation markers on their surface (ICOS on both CD4; p = 0.0013 and CD8 T cells; p = 0.016 and 4-1BB on CD4 T cells; p = 0.016). In terms of circulating metabolic information, L-Ser and L-Pro levels, which play important roles in T cell expansion and proliferation, were significantly higher in the Firmicutes-low group (p = 0.010). All of the patients with higher Firmicutes abundance had disease progression without any clinical response (p = 0.026) and significantly inferior prognosis for pembrolizumab therapy (p = 0.035). This is the first study on the importance of peripheral bacterial EVs in cancer patients treated with cancer immunotherapy.

Prognostic significance of NY-ESO-1 antigen and PIGR expression in esophageal tumors of CHP-NY-ESO-1-vaccinated patients as adjuvant therapy.

The aim of this study was to determine the efficacy and the biomarkers of the CHP-NY-ESO-1 vaccine complexed with full-length NY-ESO-1 protein and a cholesteryl pullulan (CHP) in patients with esophageal squamous cell carcinoma (ESCC) after surgery. We conducted a randomized phase II trial. Fifty-four patients with NY-ESO-1-expressing ESCC who underwent radical surgery following cisplatin/5-fluorouracil-based neoadjuvant chemotherapy were assigned to receive either CHP-NY-ESO-1 vaccination or observation as control. Six doses of CHP-NY-ESO-1 were administered subcutaneously once every two weeks, followed by nine more doses once every four weeks. The endpoints were disease-free survival (DFS) and safety. Exploratory analysis of tumor tissues using gene-expression profiles was also performed to seek the biomarker. As there were no serious adverse events in 27 vaccinated patients, we verified the safety of the vaccine. DFS in 2 years were 56.0% and 58.3% in the vaccine arm and in the control, respectively. Twenty-four of 25 patients showed NY-ESO-1-specific IgG responses after vaccination. Analysis of intra-cohort correlations among vaccinated patients revealed that 5% or greater expression of NY-ESO-1 was a favorable factor. Comprehensive analysis of gene expression profiles revealed that the expression of the gene encoding polymeric immunoglobulin receptor (PIGR) in tumors had a significantly favorable impact on outcomes in the vaccinated cohort. The high PIGR-expressing tumors that had higher NY-ESO-1-specific IgA response tended to have favorable prognosis. These results suggest that PIGR would play a major role in tumor immunity in an antigen-specific manner during NY-ESO-1 vaccinations. The IgA response may be relevant.

Tetracyclines Enhance Anti-tumor T-Cell Responses Induced by a Bispecific T-Cell Engager.

Cancer immunotherapies are powerful therapeutic options for cancer patients. To enhance the therapeutic effects of cancer immunotherapies, we plan to develop novel immunostimulatory drugs for use in combination with cancer immunotherapy. In the present study, we focused on tetracyclines, the effects of which are controversial for immunotherapy. We examined the effects of tetracyclines on human T cells in the peripheral blood of healthy donors and the tumor tissues of non-small cell lung cancer (NSCLC) patients. By using bispecific T-cell engager technology to assess the cytotoxicity of peripheral T cells against tumor cells, we showed that tetracyclines (minocycline, tetracycline, doxycycline, meclocycline, chlortetracycline, and demeclocycline) enhanced T-cell cytotoxicity through granzyme B expression and CD4+ and CD8+ T-cell proliferation. In analyses of the peripheral blood mononuclear cells (PBMCs) and lung tumor-infiltrated cells of NSCLC patients, we found that demeclocycline enhanced T-cell cytotoxicity not only in PBMCs, but also in lung tumor tissues. These results support the further application of tetracyclines to combination cancer immunotherapy.

The impact of ICOS+ regulatory T cells and Helicobacter pylori infection on the prognosis of patients with gastric and colorectal cancer: potential prognostic benefit of pre-operative eradication therapy.

It remains unclear whether Helicobacter pylori (H. pylori), a major cause of gastric cancer (GC), is involved in other intestinal cancers. In our previous study, ICOS+ Foxp3+ CD4+ T cells (ICOS+ Tregs) in GC tumors were identified as effector Tregs and associated with H. pylori. In the present study, the impact of ICOS+ Tregs on not only GC, but also colorectal cancer (CRC) and their prognosis was investigated in association with H. pylori. Tissue-infiltrating lymphocytes (TILs) purified from fresh tumor and sera were obtained from GC and CRC patients prospectively. % ICOS+ Tregs were analyzed by flow cytometry and their production of anti-H. pylori antibody (Hp-Ab) in sera was detected by ELISA. % ICOS+ Tregs were higher in GC and CRC patients with Hp-Ab than in those without Hp-Ab, including eradicated patients. ICOS+ Tregs purified had higher potential to produce IL-10 than ICOS- Tregs. For prognostic analysis, immunohistochemical analysis and ELISA were performed using archival fixed specimens and frozen sera, respectively, obtained from GC and CRC patients. Overall survival was longer in patients with low % ICOS+ Tregs than in those with high % ICOS+ Tregs, and patients with Hp-Ab showed shorter recurrence-free survival than those without Hp-Ab. These results suggested that ICOS+ Tregs in GC and CRC patients were closely associated with H. pylori in gastric epithelium and their prognosis, and that pre-operative H. pylori eradication has potential as a novel immunotherapy for GC and CRC patients.

PD-1+ Tim3+ tumor-infiltrating CD8 T cells sustain the potential for IFN-γ production, but lose cytotoxic activity in ovarian cancer.

Persistent exposure to tumor antigens results in exhausted tumor-infiltrating T cells (TILs) that express the immune checkpoint molecules, PD-1 and Tim3, and lack anti-tumor immunity. To examine the exhausted status of TILs in ovarian cancer, the potential for cytokine production, proliferation and cytotoxicity by purified PD-1+ Tim3+ CD8 TILs was assessed. The production of IFN-γ and TNF-α by PD-1+ Tim3+ CD8 TILs remained the same in an intracellular cytokine staining assay and was higher in a cytokine catch assay than that by PD-1- Tim3- and PD-1+ Tim3- CD8 TILs. %Ki67+ was higher in PD-1+ Tim3+ CD8 TILs than in PD-1- Tim3- CD8 TILs. However, patients with high PD-1+ Tim3+ CD8 TILs had a poor prognosis. The potential for cytotoxicity was then examined. %Perforin+ and %granzyme B+ were lower in PD-1+ Tim3+ CD8 TILs than in PD-1- Tim3- and PD-1+ Tim3- CD8 TILs. To observe the potential for direct cytotoxicity by T cells, a target cell line expressing membrane-bound anti-CD3scFv was newly established and a cytotoxic assay targeting these cells was performed. The cytotoxicity of PD-1+ Tim3+ CD8 TILs was significantly lower than that of PD-1- Tim3- and PD-1+ Tim3- CD8 TILs. Even though PD-1+ Tim3+ CD8 TILs in ovarian cancer showed a sustained potential for cytokine production and proliferation, cytotoxicity was markedly impaired, which may contribute to the poor prognosis of patients with ovarian cancer. Among the impaired functions of exhausted TILs, cytotoxicity may be an essential target for cancer immunotherapy.

Clinical importance of the expression of CD4+CD8+ T cells in renal cell carcinoma.

OBJECTIVE: CD4+CD8+ T cells are expressed in some cancer patients including those with renal cell carcinoma (RCC). However, no reports have mentioned the clinical importance of this expression. We evaluated the expression of CD4+CD8+ T cells in patients with various cancer types to clarify clinical characteristics and prognostic importance significantly correlating with these T cells. METHODS: Expression of CD4+CD8+ T cells was evaluated using flowcytometry in tissue-infiltrating lymphocytes extracted from 260 cancer tissues including 104 RCC samples. RNA sequencing and characterization and regression (Citrus) was used to determine characteristics. The prognostic importance of CD4+CD8+ T cells was evaluated by Cox regression analysis. RESULTS: Among eight cancer types, expression of CD4+CD8+ T cells was significantly highest in RCC patients. According to the expression of CD4+CD8+ T cells in adjacent normal tissue-infiltrating lymphocytes, 24 patients (23.1%) were defined as being positive for CD4+CD8+ with an expression higher than 9.29% in RCC patients. Citrus showed CD8+PD-1+TIM-3+CD103- T cells to be a specific subpopulation of CD4+CD8+ T cells. RNA sequencing revealed that CD4+CD8+ T cells had significantly lower diversity than the other T cells and shared most T-cell receptor clones with CD8+ not CD4+ T cells. Expression of CD4+CD8+ T cells was identified as an independent predictor of overall survival (hazard ratio: 0.11, 95% confidence interval: 0.01-0.86, P = 0.035) in multivariate analysis. CONCLUSIONS: The expression of CD4+CD8+ T cells was significantly up-regulated in RCC patients and correlated significantly with prognostic importance in surgically treated RCC patients.

Requirement for intron structures in activating the Cd8a locus.

During differentiation of CD4+CD8+ double-positive (DP) thymocytes into the CD4-CD8+ single-positive (CD8SP) thymocytes committed to the cytotoxic T cell lineage, Cd8a transcription is temporally terminated after positive selection and is subsequently reinitiated, a process known as coreceptor reversal. Despite the identification of a transcriptional enhancer in the Cd8a gene that directs reporter transgene expression specifically in CD8SP thymocytes, the molecular mechanisms controlling reactivation of the Cd8a gene are not fully understood. Here, we show that, after positive selection, hCD2 reporter expression from the Cd8a locus, which was generated by insertion of hCD2 cDNA into the first exon of the Cd8a gene, requires the incorporation of intron sequences into the hCD2 transcript. The presence of polyadenylation signals after hCD2 cDNA inhibited hCD2 expression in mature CD8+ T cells, whereas hCD2 expression in DP thymocytes recapitulated the Cd8a expression. Incorporation of the endogenous short intron structure and heterologous intron structure of the Cd4 locus restored hCD2 expression in mature CD8+ T cells in a variegated manner. Interestingly, stage-specific DNA demethylation was impaired in Cd8a reporter alleles that failed to express hCD2 in CD8+ T cells, and intron sequences lacking RNA splicing signals still restored hCD2 expression. These observations indicate that "intron-mediated enhancement" is involved in a stage-specific reactivation of the Cd8a locus harboring hCD2 cDNA. However, the Cd8a gene was transcribed in mature CD8+ T cells, albeit at a lower level, from a mutant Cd8a locus lacking intron structures, suggesting that protein-coding sequences in transcripts affect sensitivity to intron-mediated enhancement.

[Prediction of Pathological Response to Chemotherapy in Esophageal Cancer by Fluorescent Multiplex Immunohistochemistry].

To the effect of chemotherapy in cancer patients, in addition to direct cytotoxicity against cancer cells, contribution of tumor immune-mediated mechanisms have been reported. To elucidate the immune environment involved in the response to chemotherapy in esophageal cancer, we collected pre-treatment biopsy tissues from 86 patients, performed multiple staining with fluorescein-labeled tyramide, and analyzed lymphocytes and macrophages using a variable-wavelength filter fluorescence microscope to compare the effects of chemotherapy. Although there was no correlation with various T-cell fractions, high levels of CD163- or CD206-positive M2 macrophages (TAM) were significantly associated with chemotherapy non-responders. The results suggest that the combination of TAM inhibitors may be useful in overcoming chemotherapy resistance in esophageal cancer.

Tumor-infiltrating M2 macrophage in pretreatment biopsy sample predicts response to chemotherapy and survival in esophageal cancer.

The association between the tumor microenvironment (TME) and treatment response or survival has been a recent focus in several types of cancer. However, most study materials are resected specimens that were completely modified by prior chemotherapy; therefore, the unmodified host immune condition has not yet been clarified. The aim of the present study was to evaluate the relationship between TME assessed in pre-therapeutic biopsy samples and chemoresistance in esophageal cancer (EC). A total of 86 endoscopic biopsy samples from EC patients who received neoadjuvant chemotherapy (NAC) prior to surgery were evaluated for the number of intratumoral CD4+ lymphocytes (with/without Foxp3 expression), CD8+ lymphocytes (with/without PD-1 expression), monocytes (CD14+ ) and macrophages (CD86+ , CD163+ and CD206+ ) by multiplex immunohistochemistry (IHC). The number of tumor-infiltrating CD206+ macrophages I significantly correlated with cT, cM, cStage and neutrophil/lymphocyte ratio (NLR), whereas the number of lymphocytes (including expression of Foxp3 and PD-1) was not associated with clinico-pathological features. The high infiltration of CD163+ or CD206+ macrophages was significantly associated with poor pathological response to NAC (P = 0.0057 and 0.0196, respectively). Expression of arginase-1 in CD163+ macrophages tended to be higher in non-responders (29.4% vs 18.2%, P = 0.17). In addition, patients with high infiltration of M2 macrophages exhibited unfavorable overall survival compared to those without high infiltration of M2 macrophages (5-year overall survival 57.2% vs 71.0%, P = 0.0498). Thus, a comprehensive analysis of TME using multiplex IHC revealed that M2 macrophage infiltration would be useful in predicting the response to NAC and long-term survival in EC patients.

Endogenous CXCL9 affects prognosis by regulating tumor-infiltrating natural killer cells in intrahepatic cholangiocarcinoma.

CXCL9, an IFN-γ inducible chemokine, has been reported to play versatile roles in tumor-host interrelationships. However, little is known about its role in intrahepatic cholangiocarcinoma (iCCA). Here, we aimed to elucidate the prognostic and biological implications of CXCL9 in iCCA. Endogenous CXCL9 expression and the number of tumor-infiltrating lymphocytes were immunohistochemically assessed in resection specimens. These data were validated in mice treated by silencing CXCL9 with short hairpin RNA. In addition, the induction of endogenous CXCL9 and the effects of CXCL9 on tumor biological behaviors were evaluated in human cholangiocarcinoma cell lines. Immunohistochemical analyses revealed that high CXCL9 expression was closely correlated with prolonged postoperative survival and a large number of tumor-infiltrating natural killer (NK) cells. In fact, due to the trafficking of total and tumor necrosis factor-related apoptosis-inducing ligand-expressing NK cells into tumors, CXCL9-sufficient cells were less tumorigenic in the liver than CXCL9-deficient cells in mice. Although CXCL9 involvement in tumor growth and invasion abilities differed across cell lines, it did not exacerbate these abilities in CXCL9-expressing cell lines. We showed that CXCL9 was useful as a prognostic marker. Our findings also suggested that CXCL9 upregulation might offer a therapeutic strategy for treating CXCL9-expressing iCCA by augmenting anti-tumor immune surveillance.

Heterogeneity of Treg/Th17 According to Cancer Progression and Modification in Biliary Tract Cancers via Self-Producing Cytokines.

BACKGROUND/AIM: We previously demonstrated that inflammatory cytokine interleukin-6 (IL-6) was produced during cancer progression, worked together with transforming growth factor-beta 1 (TGF-ß1), and induced the epithelial-mesenchymal transition (EMT) with chemo-resistance against gemcitabine (GR) at the invasion front of biliary tract cancers (BTCs). However, the significance of cytokine-induced T cell accumulation at the tumor microenvironment in biliary tract cancer (BTC) is not well understood. Because these cytokines (IL-6 and TGF-ß1) are able to differentiate naïve T cells into Foxp3-expressing T cells (Tregs) and/or IL-17-producing T helper 17 (Th17) cells, we investigated the relationship between heterogeneous, cancer-producing cytokines and T cell differentiation. METHODS: In total, 127 curative resected specimens from patients with BTCs at Osaka University Hospital between 2000 and 2012 were evaluated for IL-6, TGF-ß1, Tregs, and Th17 cells by immunohistochemistry. The ability of BTC-GR cells to undergo T cell differentiation was investigated in vitro. RESULTS: Tregs accumulated at the tumor center and Th17 cells accumulated at the invasion front during cancer progression and/or metastasis; each signaled poor prognosis. Treg accumulation was related to TGF-ß1 expression by cancer cells, and Th17 cell accumulation was related to IL-6 expression by cancer cells, in resected specimens; this was confirmed in vitro. Compared with parent cells, GR cells produced IL-6 but not TGF-ß1 in a time-dependent manner, had EMT features, and induced T cell differentiation to Th17 cells but not Tregs. CONCLUSION: Cytokines produced by cancer cells (IL-6 and TGF-ß1) induced heterogeneity of Tregs and Th17 cells in the tumor microenvironment, supporting progression of BTC.

Docetaxel Upregulates HMGB1 Levels in Non-small Cell Lung Cancer.

Immune checkpoint inhibitors (ICIs) exert beneficial effects in non-small cell lung cancer (NSCLC) patients. However, ICIs are only advantageous for a limited population of NSCLC patients. Therefore to enhance their effects, combination therapies with ICIs have been developed. To identify preferable chemotherapy to combine with ICIs against lung cancer, we examined immunological effects of docetaxel compared with epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI). We found no difference in peripheral lymphocyte counts and ratio of their subpopulations in lung cancer patients before and after both treatments. On the other hand, plasma levels of high-mobility group box 1 (HMGB1), a damage-associated molecular pattern (DAMP) protein, showed significant increase after docetaxel treatment. Furthermore, we investigated effects of HMGB1 on tumor-infiltrating immune cells obtained from surgically resected tumor tissue from NSCLC patients. When the tumor infiltrating cells were stimulated with HMGB1, CD11c+ cells showed increased expression of activation markers. These findings imply that docetaxel could be involved in anti-tumor immunity via HMGB1. Therefore docetaxel might be a candidate for combination treatment with ICIs.