Galectin-10 in serum extracellular vesicles reflects asthma pathophysiology.

BACKGROUND: Novel biomarkers (BMs) are urgently needed for bronchial asthma (BA) with various phenotypes and endotypes. OBJECTIVE: We sought to identify novel BMs reflecting tissue pathology from serum extracellular vesicles (EVs). METHODS: We performed data-independent acquisition of serum EVs from 4 healthy controls, 4 noneosinophilic asthma (NEA) patients, and 4 eosinophilic asthma (EA) patients to identify novel BMs for BA. We confirmed EA-specific BMs via data-independent acquisition validation in 61 BA patients and 23 controls. To further validate these findings, we performed data-independent acquisition for 6 patients with chronic rhinosinusitis without nasal polyps and 7 patients with chronic rhinosinusitis with nasal polyps. RESULTS: We identified 3032 proteins, 23 of which exhibited differential expression in EA. Ingenuity pathway analysis revealed that protein signatures from each phenotype reflected disease characteristics. Validation revealed 5 EA-specific BMs, including galectin-10 (Gal10), eosinophil peroxidase, major basic protein, eosinophil-derived neurotoxin, and arachidonate 15-lipoxygenase. The potential of Gal10 in EVs was superior to that of eosinophils in terms of diagnostic capability and detection of airway obstruction. In rhinosinusitis patients, 1752 and 8413 proteins were identified from EVs and tissues, respectively. Among 11 BMs identified in EVs and tissues from patients with chronic rhinosinusitis with nasal polyps, 5 (including Gal10 and eosinophil peroxidase) showed significant correlations between EVs and tissues. Gal10 release from EVs was implicated in eosinophil extracellular trapped cell death in vitro and in vivo. CONCLUSION: Novel BMs such as Gal10 from serum EVs reflect disease pathophysiology in BA and may represent a new target for liquid biopsy approaches.

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.

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.

Identification of CD14 and lipopolysaccharide-binding protein as novel biomarkers for sarcoidosis using proteomics of serum extracellular vesicles.

Sarcoidosis is a complex, polygenic, inflammatory granulomatous multi-organ disease of unknown cause. The granulomatous inflammation in sarcoidosis is driven by the interplay between T cells and macrophages. Extracellular vesicles (EVs) play important roles in intercellular communication. We subjected serum EVs, isolated by size exclusion chromatography, from seven patients with sarcoidosis and five control subjects to non-targeted proteomics analysis. Non-targeted, label-free proteomics analysis detected 2292 proteins in serum EVs; 42 proteins were up-regulated in patients with sarcoidosis relative to control subjects; and 324 proteins were down-regulated. The protein signature of EVs from patients with sarcoidosis reflected disease characteristics such as antigen presentation and immunological disease. Candidate biomarkers were further verified by targeted proteomics analysis (selected reaction monitoring) in 46 patients and 10 control subjects. Notably, CD14 and lipopolysaccharide-binding protein (LBP) were validated by targeted proteomics analysis. Up-regulation of these proteins was further confirmed by immunoblotting, and their expression was strongly increased in macrophages of lung granulomatous lesions. Consistent with these findings, CD14 levels were increased in lipopolysaccharide-stimulated macrophages during multinucleation, concomitant with increased levels of CD14 and LBP in EVs. The area under the curve values of CD14 and LBP were 0.81 and 0.84, respectively, and further increased to 0.98 in combination with angiotensin-converting enzyme and soluble interleukin-2 receptor. These findings suggest that CD14 and LBP in serum EVs, which are associated with granulomatous pathogenesis, can improve the diagnostic accuracy in patients with sarcoidosis.

IL-33 Induces Sema4A Expression in Dendritic Cells and Exerts Antitumor Immunity.

Cancer immunotherapy has shown great promise as a new standard therapeutic strategy against cancer. However, the response rate and survival benefit remain unsatisfactory because most current approaches, such as the use of immune checkpoint inhibitors, depend on spontaneous antitumor immune responses. One possibility for improving the efficacy of immunotherapy is to promote antitumor immunity using adjuvants or specific cytokines actively. IL-33 has been a candidate for such cytokine therapies, but it remains unclear how and in which situations IL-33 exerts antitumor immune effects. In this study, we demonstrate the potent antitumor effects of IL-33 using syngeneic mouse models, which included marked inhibition of tumor growth and upregulation of IFN-γ production by tumor-infiltrating CD8+ T cells. Of note, IL-33 induced dendritic cells to express semaphorin 4A (Sema4A), and the absence of Sema4A abolished the antitumor activity of IL-33, indicating that Sema4A is intrinsically required for the antitumor effects of IL-33 in mice. Collectively, these results not only present IL-33 and Sema4A as potential therapeutic targets but also shed light on the potential use of Sema4A as a biomarker for dendritic cell activation status, which has great value in various fields of cancer research, including vaccine development.

Opposite response of lung adenocarcinoma and its choroidal metastases upon ramucirumab plus docetaxel therapy after immunotherapy: a case report.

We report a unique case of advanced non-small cell lung cancer that exhibited the opposite response to its unilateral choroidal metastases upon ramucirumab plus docetaxel treatment. A combination of cisplatin, pemetrexed, and pembrolizumab was administered as first-line treatment, resulting in shrinkage of all the lesions. However, although the patient was continued on a course of pembrolizumab, all the lesions had recurred approximately two months later. Ramucirumab plus docetaxel, administered as sequential treatment, resulted in maintained shrinkage of the choroidal lesions, yet all the other lesions progressed. Ramucirumab may be a suitable therapy for choroidal metastases, especially if administered immediately after immunotherapy.

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.

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.

Cytotoxic CD8+ Lymphocytes in the Tumor Microenvironment.

In the tumor microenvironment, CD8+ T cells play a major role in tumor immunity. CD8+ T cells differentiate to cytotoxic T cells, traffic into the tumor microenvironment, and exhibit cytotoxicity against tumor cells. These processes have both positive and negative effects. Enhancements in the cytotoxic activity of tumor antigen-specific cytotoxic T cells in the tumor microenvironment are crucial for the development of cancer immunotherapy. To achieve this, several immunotherapies, including cancer vaccines, T cells engineered to express chimeric antigen receptors (CAR T cells), and bispecific T-cell engagers (BiTEs), have been developed. In contrast to cancer vaccines, CAR T cells, and BiTEs, immune checkpoint inhibitors enhance the activity of cytotoxic T cells by inhibiting the negative regulators of T cells.The total number, type, and activity of tumor antigen-specific cytotoxic T cells in the tumor microenvironment need to be clarified, particularly for the development of companion diagnostics to identify patients for whom these therapies are effective. Therefore, technologies including TCR repertoire, single-cell, and T-cell cytotoxicity analyses using BiTEs have been developed.Based on these and future innovations, the generation of effective cancer immunotherapies is anticipated.

Peri-operative monocyte count is a marker of poor prognosis in gastric cancer: increased monocytes are a characteristic of myeloid-derived suppressor cells.

Gastric cancer (GC) is the most common malignant tumor in digestive organs, and the prognosis of GC patients who have undergone surgery remains poor because of frequent recurrence. Therefore, the identification of new markers to predict the outcome of these patients is needed. Monocyte count is a negative prognostic factor associated with inflammation. We investigated the relationship between peripheral monocytes in the peri-operative period and prognosis in GC patients. A high pre-operative monocyte count was identified as a prognostic factor in a retrospective analysis of 278 stage II and III GC patients who underwent curative gastrectomy. In contrast, an increased post-operative monocyte count compared to the pre-operative monocyte count was a marker of poor prognosis, particularly for early relapse. In a prospective analysis of 75 GC patients, a subset of the increased post-operative monocytes was similar to CD14+ HLA-DR- CD11b+ CD33+ cells by flow cytometry, and these monocytes produced IDO and arginase and suppressed T cell functions; therefore, we classified these cells as monocytic myeloid-derived suppressive cells (M-MDSCs). Peri-operative neutrophils and C-reactive protein (CRP), which are also related to inflammation, did not affect the prognosis of GC patients, and a neutrophil immunosuppressive function was not observed. These results suggest that peripheral monocytes in the peri-operative period in GC patients are a useful marker for the prognosis of GC patients, and a subset of increased post-operative monocytes may be characterized as M-MDSCs.

A lung abscess caused by secondary syphilis - the utility of polymerase chain reaction techniques in transbronchial biopsy: a case report.

BACKGROUND: In Japan and other countries, the number of patients with syphilis is increasing year by year. Recently, the cases of the pulmonary involvement in patients with secondary syphilis have been reported. However, it is still undetermined how to obtain a desirable specimen for a diagnosis of the pulmonary involvement, and how to treat it if not cured. CASE PRESENTATION: A 34-year-old man presented with cough and swelling of the right inguinal nodes. A physical examination revealed erythematous papular rash over the palms, soles and abdomen. A 4 cm mass in the right lower lobe of the lung was detected on computed tomography. He was diagnosed as having secondary syphilis, because he was tested positive for the rapid plasma reagin and Treponema pallidum hemagglutination assay. Amoxycillin and probenecid were orally administered for 2 weeks. Subsequently, rash and serological markers were improved, however, the lung mass remained unchanged in size. Transbronchial biopsy (TBB) confirmed the pulmonary involvement of syphilis using polymerase chain reaction techniques (tpp47- and polA-PCR). Furthermore, following surgical resection revealed the lung mass to be an abscess. CONCLUSIONS: To our knowledge, this is the first surgically treated case of a lung abscess caused by syphilis, which was diagnosed by PCR techniques in TBB. This report could propose a useful diagnostic method for the pulmonary involvement of syphilis.

Increased Tim-3+ T cells in PBMCs during nivolumab therapy correlate with responses and prognosis of advanced esophageal squamous cell carcinoma patients.

The recent development of immune checkpoint inhibitors for many types of cancers has prompted us to identify markers that predict patients with clinical benefits. Several trials on nivolumab for the treatment of esophageal squamous cell carcinoma (ESCC) have been performed worldwide, and the identification of markers specific to ESCC is urgently needed. We conducted a clinical trial on nivolumab for advanced ESCC (JapicCTI-No.142422) and investigated markers using peripheral blood collected from 20 patients enrolled in our institute, including 1 with a complete response (CR), 5 with a partial response (PR), 6 with a stable disease (SD), and 8 with a progressive disease (PD) as clinical responses. The expression of surface molecules and cytokine production by T cells were analyzed using flow cytometry, and clinicopathological factors and general blood parameters were examined. Albumin, neutrophils, %Tim3, %OX40, %CD103, %CD45RA-CD27-, and IL-1b after the first cycle of nivolumab treatment, but not at baseline, distinguished CR/PR from SD/PD patients. When markers to distinguish longer survivors with nivolumab therapy were analyzed, changes in these levels between baseline and after the first cycle of nivolumab treatment, but not levels at each period, were indicative, similar to the tumor burden. Among them, elevations in %Tim-3+CD4 had a marked impact on survival rates. In conclusion, dynamic elevations in %Tim-3 in T cells in the early period of nivolumab therapy have potential as a marker for the clinical responses and prognosis of advanced ESCC patients.

Immunological classification of renal cell carcinoma patients based on phenotypic analysis of immune check-point molecules.

OBJECTIVES: To clarify comprehensive immunological signature patterns of tumour tissue-infiltrating lymphocytes in patients with renal cell carcinoma and show its clinical significance. MATERIALS AND METHODS: We investigated the surface marker expressions of tumour tissue-infiltrating lymphocytes quantitatively and classified them based on their functional populations. We extracted 109 sets of tumour tissue-infiltrating lymphocytes from 80 patients who underwent surgical resection of renal cell carcinoma, of which 44 tumour tissue-infiltrating lymphocytes were multiply extracted from 15 patients. Each tumour tissue-infiltrating lymphocyte was characterised on the basis of functional T-cell populations using ten surface marker expressions measured by flow cytometry. RESULTS: All sets of the tumour tissue-infiltrating lymphocytes were classified into three groups, which correlated significantly with Fuhrman grade (OR 0.253, 95% CI 0.094-0.678, P = 0.006). Importantly, both overall metastasis-free survival (HR 0.449, 95% CI 0.243-0.832, P = 0.011) and recurrence-free survival (HR 0.475, 95% CI 0.238-0.948, P = 0.035) of the patients with the higher marker expressions were significantly inferior to those of the patients with the lower marker expressions by multivariate analysis. Six specific genes for this classification identified by microarray analysis verified our results using the TCGA KIRC data set. In addition, we discovered the presence of intra-tumoural diversity in the classification of 3 (20%) of the 15 patients. CONCLUSIONS: This study showed that the presence of classable diversity in the immunological signature of tumour tissue-infiltrating lymphocytes correlated with prognosis and tumour aggressiveness that was observed even within individual tumours in some patients with renal cell carcinoma.

[A Case of Mediastinal Small Cell Lung Cancer in a Patient Receiving Mechanical Ventilation Who Was Successfully Treated with Chemotherapy and Finally Extubated].

BACKGROUND: The efficacy and safety of chemotherapy for patients with lung cancer who are in need of intensive care, such as invasive mechanical ventilation, have not been established. CASE: A 59-year-old woman consulted a doctor with complaints of dyspnea.She was intubated because of acute respiratory failure and transferred to our hospital.Enhanced CT images revealed advanced stenosis of her trachea due to a bulky mediastinal tumor.Cervical lymph node biopsy was performed, and she was diagnosed with mediastinal small cell lung cancer.She received combination chemotherapy with carboplatin and etoposide along with invasive mechanical ventilation.Chemotherapy was effective, and extubation was performed under careful bronchoscopic observation.Her general condition improved gradually, and she was discharged from our hospital on foot with ambulatory chemotherapy. CONCLUSION: Even though patients with lung cancer develop respiratory failure and need invasive mechanical ventilation, they may be treated with effective chemotherapy and may be weaned from ventilation.

ICOS+ Foxp3+ TILs in gastric cancer are prognostic markers and effector regulatory T cells associated with Helicobacter pylori.

Regulatory T cells (Tregs) have an immunosuppressive role in the tumor microenvironment. Since effector Tregs (eTregs), which have highly suppressive functions, are located in a subpopulation of Foxp3+ CD4+ Tregs, the TCR-inducible costimulatory receptor (ICOS) was applied as a marker of eTregs that infiltrated gastric cancer tissue and the induction pathway of ICOS+ Foxp3+ cells was analyzed by flow cytometry and immunohistochemistry. In tumor-infiltrating lymphocytes (TILs), ICOS+ Foxp3+ CD4+ T cells were abundantly observed in the late stages of gastric cancer. ICOS+ CD4+ TILs exhibited the ability to produce IL-10, but not IFN-γ, TNF, or IL-17 and also to suppress the proliferation of CFSE-labeled responder CD8+ T cells. With the agonistic ICOS-L protein (rICOS-L Ig), ICOS+ Foxp3+ cells were efficiently induced from naive CD4+ T cells under a stimulation with TGF-ß and CD3/CD28 mAbs. Furthermore, when A*0201 PBMCs were cultured with the CMV or Melan-A antigenic peptide and rICOS-L Ig, the induction of CMV or Melan-A tetramer-binding CD8+ T cells, respectively, was inhibited. The expression of ICOS in Foxp3+ cells was closely related to plasmacytoid dendritic cells (pDCs) and their expression of ICOS-L and TLR9 as well as Helicobacter pylori infection. Collectively, our results demonstrate the potential of ICOS as a promising target for direct Treg-targeting therapeutic agents for gastric cancer, and that of eradicating therapy for H. pylori as an indirect immune therapy for gastric cancer.

Trastuzumab emtansine suppresses the growth of HER2-positive small-cell lung cancer in preclinical models.

Overcoming chemoresistance is essential for achieving better prognoses in SCLC. Previously, we reported that HER2 is upregulated when HER2-positive SCLC cells acquire chemoresistance. HER2-upregulated cisplatin- or etoposide-resistant SCLC cells were sensitive to trastuzumab-mediated ADCC. However, irinotecan-resistant SCLC cells, such as SBC-3/SN-38, were refractory to trastuzumab despite high HER2 expression. To address this issue, we examined the antitumor efficacy of trastuzumab emtansine (T-DM1) on trastuzumab-resistant HER2-positive SCLC. Treatment with T-DM1 significantly suppressed the growth of SBC-3/SN-38 xenografts in mice compared with trastuzumab (P < 0.05). Histological analysis of xenografts was performed to evaluate the therapeutic effect on apoptosis, proliferation and tumor vasculature. T-DM1 monotherapy induced apoptosis in SBC-3/SN-38 xenografts to a greater extent than trastuzumab monotherapy with the apoptotic index of 3.71 ± 1.56% vs. 0.60 ± 0.32% (P < 0.05), and also inhibited the proliferation of tumor cells compared with trastuzumab with the proliferative index of 74.30 ± 5.54% vs. 80.12 ± 4.81% (P < 0.05). On the other hand, no significant difference in micro vessel density was observed between the treatment groups. In vivo imaging using fluorescence-labeled T-DM1 showed that intravenously administered T-DM1 was rapidly delivered to xenografts and continued to accumulate for several days in a HER2-selective fashion. From these findings, delivery of the cytotoxic agent DM1 into cells via HER2-mediated internalization is expected to exert antitumor effect in such ADCC-lacking SCLC cells. Collectively, T-DM1 will be a promising option for overcoming trastuzumab-resistance in HER2-upregulated SCLC.

CD123-Engager T Cells as a Novel Immunotherapeutic for Acute Myeloid Leukemia.

Immunotherapy with CD123-specific T-cell engager proteins or with T cells expressing CD123-specific chimeric antigen receptors is actively being pursued for acute myeloid leukemia. T cells secreting bispecific engager molecules (ENG-T cells) may present a promising alternative to these approaches. To evaluate therapeutic potential, we generated T cells to secrete CD123/CD3-bispecific engager molecules. CD123-ENG T cells recognized primary acute myeloid leukemia (AML) cells and cell lines in an antigen-dependent manner as judged by cytokine production and/or tumor killing, and redirected bystander T cells to AML cells. Infusion of CD123-ENG T cells resulted in regression of AML in xenograft models conferring a significant survival advantage of treated mice in comparison to mice that received control T cells. At high effector to target ratios, CD123-ENG T cells recognized normal hematopoietic stem and progenitor cells (HSPCs) with preferential recognition of HSPCs from cord blood compared to bone marrow. We therefore introduced the CD20 suicide gene that can be targeted in vivo with rituximab into CD123-ENG T cells. The expression of CD20 did not diminish the anti-AML activity of CD123-ENG T cells, but allowed for rituximab-mediated ENG-T cell elimination. Thus, ENG-T cells coexpressing CD20 suicide and CD123 engager molecules may present a promising immunotherapeutic approach for AML.