Tumor expression of B7-H4 predicts poor survival of patients suffering from gastric cancer

Expression of Immune Checkpoints in Malignant Tumors: Therapy Targets and Biomarkers for the Gastric Cancer Prognosis

To increase the effectiveness of anticancer therapy based on immune checkpoint (IC) inhibition, some ICs are being investigated in addition to those used in clinic. We reviewed data on the relationship between PD-L1, B7-H3, B7-H4, IDO1, Galectin-3 and -9, CEACAM1, CD155, Siglec-15 and ADAM17 expression with cancer development in complex with the results of clinical trials on their inhibition. Increased expression of the most studied ICs—PD-L1, B7-H3, and B7-H4—is associated with poor survival; their inhibition is clinically significant. Expression of IDO1, CD155, and ADAM17 is also associated with poor survival, including gastric cancer (GC). The available data indicate that CD155 and ADAM17 are promising targets for immune therapy. However, the clinical trials of anti-IDO1 antibodies have been unsatisfactory. Expression of Galectin-3 and -9, CEACAM1 and Siglec-15 demonstrates a contradictory relationship with patient survival. The lack of satisfactory results of these IC inhibitor clinical trials additionally indicates the complex nature of their functioning. In conclusion, in many cases it is important to analyze the expression of other participants of the immune response besides target IC. The PD-L1, B7-H3, B7-H4, IDO1 and ADAM17 may be considered as candidates for prognosis markers for GC patient survival.

B7-H3 as a Target for CAR-T Cell Therapy in Skull Base Chordoma

Objective

chordomas are rare bone tumors with few therapeutic options. Skull base and sacrum are the two most common origin sites. Immunotherapies are emerging as the most promising approaches to fight various cancers. This study tends to identify new cell surface targets for immunotherapeutic options of skull base chordomas.

Methods

we profiled 45 skull base chordoma clinical samples by immunohistochemistry for the expression of six CAR-Targets (PD-L1, B7-H3, B7-H4, VISTA, HER2 and HER3). In addition, we generated B7-H3 targeted CAR-T-cells and evaluated their antitumor activities in vitro.

Results

We found that B7-H3 was positively stained in 7 out of 45 (16%) chordoma samples and established an expression hierarchy for these antigens (B7-H3 > HER3 > PD-L1 > HER2 = VISTA = B7-H4). We then generated a B7-H3 targeted CAR vector and demonstrated that B7-H3-CAR-T-cells recognized antigen positive cells and exhibited significant antitumor effects, including suppression of tumor spheroid formation, CAR-T-cell activation and cytokine secretion.

Conclusions

Our results support B7-H3 might serve as a promising target for CAR-T-cell therapies against chordomas.

The Positive and Negative Immunoregulatory Role of B7 Family: Promising Novel Targets in Gastric Cancer Treatment

Gastric cancer (GC), with a heterogeneous nature, is the third leading cause of death worldwide. Over the past few decades, stable reductions in the incidence of GC have been observed. However, due to the poor response to common treatments and late diagnosis, this cancer is still considered one of the lethal cancers. Emerging methods such as immunotherapy with immune checkpoint inhibitors (ICIs) have transformed the landscape of treatment for GC patients. There are presently eleven known members of the B7 family as immune checkpoint molecules: B7-1 (CD80), B7-2 (CD86), B7-H1 (PD-L1, CD274), B7-DC (PDCD1LG2, PD-L2, CD273), B7-H2 (B7RP1, ICOS-L, CD275), B7-H3 (CD276), B7-H4 (B7x, B7S1, Vtcn1), B7-H5 (VISTA, Gi24, DD1α, Dies1 SISP1), B7-H6 (NCR3LG1), B7-H7 (HHLA2), and Ig-like domain-containing receptor 2 (ILDR2). Interaction of the B7 family of immune-regulatory ligands with the corresponding receptors resulted in the induction and inhibition of T cell responses by sending co-stimulatory and co-inhibitory signals, respectively. Manipulation of the signals provided by the B7 family has significant potential in the management of GC.

Development of a novel anti-B7-H4 antibody enhances anti-tumor immune response of human T cells

BACKGROUND

B7-H4 is a member of the B7 superfamily that is expressed on the surface of tumors and exhibits limited expression on normal tissue. B7-H4 negatively regulates tumor immunity by interacting with the B7-H4 receptor, which is expressed by activated CD8 + T cells. Hence, we sought to generate an immunomodulatory antibody that targets B7-H4 and blocks the immunosuppressive activity of B7-H4.

METHODS

Anti-B7-H4 antibodies were generated using the hybridoma technique and screened by a binding assay based on B7-H4-expressing tumor cells. The B7-H4 antagonistic antibodies were further screened based on their checkpoint blockade activity using a SEB-stimulated peripheral blood mononuclear cell (PBMC) assay, which comprised B7-H4-expressing antigen presenting cells (APCs) and activated T cells. To assess the immunomodulatory activity of anti-B7-H4 antibodies, activated human CD8+ T cells were cultured in B7-H4 protein-coated plates, and the production of IL-2 and the proliferation rate of CD8+ T cells were measured. In addition, we evaluated the ADCC effect of anti-B7-H4 antibodies against tumor cell lines. The in vivo antitumor efficacy of the anti-B7-H4 antibody was also evaluated in human T cell-engrafted NOG mice.

RESULTS

A panel of anti-B7-H4 antibodies was generated. The top 23 antibodies were screened to identify antibodies that disabled B7-H4-mediated inhibition. Antibody 17 exhibited the greatest induction of the production of IL-2 and IFN-gamma in SEB-stimulated PBMCs. Antibody 17 was constructed as a chimeric antibody (CH17) with a human IgG1 constant domain. CH17 showed high affinity for human B7-H4 and fully cross-reacted with cynomolgus B7-H4. Additionally, CH17 mediated potent antibody-dependent cell cytotoxicity (ADCC) against different B7-H4-positive tumor cell lines. More importantly, CH17 relieved B7-H4-mediated T cell suppression by enhancing IL2 production and promoting T cell proliferation. In an MDA-MB-468-bearing mouse model in which human pan-T cells were engrafted, CH17 delayed tumor growth by engaging T cells and exerted a synergistic effect in combination with an anti-human PD-1 antibody.

CONCLUSIONS

We successfully generated an immunomodulatory antibody targeting B7-H4 that possesses both T cell immune checkpoint inhibitory activity and ADCC activity in B7-H4-positive tumors. B7-H4-targeting antibodies might represent a promising immunotherapy for B7-H4-expressing tumors.

Granulocyte-Macrophage Colony-Stimulating Factor-Activated Neutrophils Express B7-H4 That Correlates with Gastric Cancer Progression and Poor Patient Survival

Neutrophils are prominent components of gastric cancer (GC) tumors and exhibit distinct phenotypes in GC environment. However, the phenotype, regulation, and clinical relevance of neutrophils in human GC are presently unknown. Here, immunohistochemistry, real-time PCR, and flow cytometry analyses were performed to examine levels and phenotype of neutrophils in samples from 41 patients with GC, and also isolated, stimulated, and/or cultured neutrophils for in vitro regulation assays. Finally, we performed Kaplan-Meier plots for overall survival by using the log-rank test to evaluate the clinical relevance of neutrophils and their subsets. In our study, neutrophils in tumor tissues were significantly higher than those in nontumor tissues and were positively associated with tumor progression but negatively correlated with GC patient survival. Most intratumoral neutrophils showed an activated CD54⁺ phenotype and expressed high-level immunosuppressive molecule B7-H4. Tumor tissue culture supernatants from GC patients induced neutrophils to express CD54 and B7-H4 in both time-dependent and dose-dependent manners. Locally enriched CD54⁺ neutrophils and B7-H4⁺ neutrophils positively correlated with increased granulocyte-macrophage colony-stimulating factor (GM-CSF) detection ex vivo, and in vitro GM-CSF induced the expression of CD54 and B7-H4 on neutrophils in a time-dependent and dose-dependent manner. Moreover, GC tumor-derived GM-CSF activated neutrophils and induced neutrophil B7-H4 expression via Janus kinase (JAK)-signal transducer and activator of transcription 3 (STAT3) signaling pathway activation. Furthermore, higher intratumoral B7-H4⁺ neutrophil percentage/number was found in GC patients with advanced tumor node metastasis stage and reduced overall survival following surgery. Our results illuminate a novel regulating mechanism of B7-H4 expression on tumor-activated neutrophils in GC, suggesting that functional inhibition of these novel GM-CSF-B7-H4 pathways may be a suitable therapeutic strategy to treat the immune tolerance feature of GC.

B7-H4 induces epithelial-mesenchymal transition and promotes colorectal cancer stemness

B7-H4 is a unique negative regulator of T cells that is typically significantly overexpressed in various carcinomas and is associated with poor prognosis. However, the effects of B7-H4 expression on epithelial-mesenchymal transition (EMT) and cancer stemness of colorectal cancer (CRC) are not entirely clear. In the present study, we used tissue samples from 98 patients with CRC and CRC cell lines to determine the clinicopathological significance of B7-H4 in CRC and its effects on CRC stemness. We performed immunohistochemical staining; immunofluorescence imaging; western blotting; and tumor sphere formation, wound healing, transwell migration, and in vivo tumorigenesis assays. B7-H4 expression was upregulated in CRC tissues and was associated with lymph node metastasis, distant metastasis, clinical stage, a shorter overall survival rate, and disease-free survival rate. Cox regression analyses indicated that B7-H4 is an independent poor prognostic factor for CRC. In addition, B7-H4 expression was correlated with the expression of EMT-related proteins and cancer stemness-related proteins. Moreover, immunohistochemical and immunofluorescence analyses revealed that B7-H4 was correlated with CD133 and CD44 expression levels in both CRC tissues and HT29 and HCT116 cell lines. Conversely, B7-H4 knockdown downregulated the expression of EMT- and cancer stemness-related proteins, while inhibiting tumor spheroid formation, cell migration, and invasion of CRC cell lines. These results indicate that B7-H4 can promote EMT and may be a novel stem cell marker, suggesting its potential as a prognostic biomarker for CRC.

Measuring Cancer Hallmark Mediation of the TET1 Glioma Survival Effect with Linked Neural-Network Based Mediation Experiments

This paper examines the effect of TET1 expression on survival in glioma patients using open-access data from the Genomic Data Commons. A neural network-based survival model was built on expression data from a selection of genes most affected by TET1 knockdown with a median cross-validated survival concordance of 82.5%. A synthetic experiment was then conducted that linked two separately trained neural networks: a multitask model estimating cancer hallmark gene expression from TET1 expression, and a survival neural network. This experiment quantified the mediation of the TET1 survival effect through eight cancer hallmarks: apoptosis, cell cycle, cell death, cell motility, DNA repair, immune response, two phosphorylation pathways, and a randomized gene sets. Immune response, DNA repair, and apoptosis displayed greater mediation than the randomized gene set. Cell motility was inversely associated with only 12.5% mediated concordance. We propose the neural network linkage mediation experiment as an approach to collecting evidence of hazard mediation relationships with prognostic capacity useful for designing interventions.

B7-H4 facilitates proliferation and metastasis of colorectal carcinoma cell through PI3K/Akt/mTOR signaling pathway

B7-H4 is over-expressed in various tumors and may affect many aspects of cancer biology. Our previous studies have reported that the over-expressed B7-H4 in serum or tumor tissue of colorectal carcinoma (CRC) patients was closely related to CRC progression. However, B7-H4 in cell biological characteristics of CRC is not well studied. Here, we investigate the effect of the B7-H4 on cell proliferation, migration and its expression regulated by PI3K/Akt/mTOR signaling pathway in CRC. Firstly, pSilencer 4.1-B7-H4-shRNA vector was constructed and stable transfection was performed on HT-29 cells. Secondly, cell proliferation, cell cycle, cell apoptosis and cell migration were evaluated after B7-H4 silencing, and the expression of Bcl-2, caspase-3, MMP-2 and MMP-9 was also measured. Finally, the regulation of B7-H4 by PI3K/Akt/mTOR signaling pathway was measured followed by treatment with or without PI3K/Akt and mTOR inhibitor. The results showed that the viability of HT-29 cells was significantly decreased after B7-H4 silencing (P < 0.05). B7-H4 silencing significantly increased the apoptosis rate and caspase-3 protein expression while decreased Bcl-2 protein expression (P all < 0.05). B7-H4 silencing also significantly reduced the migration of HT-29 cells (P < 0.01) and the secretion of MMP-2 or MMP-9 (P all < 0.05). Following treatment with PI3K/Akt and mTOR inhibitor in HT-29 cells, the expression of B7-H4 was significantly downregulated compared with untreated group (P all < 0.05). Our results strongly suggest that B7-H4 may be involved in cell proliferation and migration by PI3K/Akt/mTOR signaling pathway. Therefore, blocking B7-H4 signaling might be a novel treatment strategy for CRC.

The B7x Immune Checkpoint Pathway: From Discovery to Clinical Trial

B7x (B7 homolog x, also known as B7-H4, B7S1, and VTCN1) was discovered by ourselves and others in 2003 as the seventh member of the B7 family. It is an inhibitory immune checkpoint of great significance to human disease. Tissue-expressed B7x minimizes autoimmune and inflammatory responses. It is overexpressed in a broad spectrum of human cancers, where it suppresses antitumor immunity. Further, B7x and PD-L1 tend to have mutually exclusive expression in cancer cells. Therapeutics targeting B7x are effective in animal models of cancers and autoimmune disorders, and early-phase clinical trials are underway to determine the efficacy and safety of targeting B7x in human diseases. It took 15 years moving from the discovery of B7x to clinical trials. Further studies will be necessary to identify its receptors, reveal its physiological functions in organs, and combine therapies targeting B7x with other treatments.

Expression of co-inhibitory molecules B7-H4 and B7-H1 in Epstein-Barr virus positive diffuse large B-cell lymphoma and their roles in tumor invasion

To investigate the relationship between immunoregulatory molecules B7-H4 and B7-H1 in Epstein-Barr positive diffuse large B-cell lymphoma (EBV⁺DLBCL). Immunohistochemistry was used to detect the expression of B7-H4 and B7-H1 in tumor tissues of 13 patients with EBV⁺DLBCL. The expression levels of B7-H4 and B7-H1 in four diffuse large B-cell lymphoma cell lines (SU-DHL-4, SU-DHL-10, SU-DHL-6, Pfeiffer) were analyzed by flow cytometry. Transwell invasion assays were conducted to observe the invasive ability of cell lines. B7-H4 and B7-H1 were expressed in 84.62% and 100% tumor specimens of EBV⁺DLBCL. The overexpression of B7-H4 and B7-H1 was found in 46.15% and 23.08% tumor samples of EBV⁺DLBCL. There was a medium negative correlation between the expression levels of B7-H4 and B7-H1 (r = -0.667, P = 0.013, spearman rank correlation). The expression levels of B7-H1 in four diffuse large B-cell lymphoma cell lines were positively correlated with their invasive ability, whereas the expression levels of B7-H4 were not. Here, we provide evidence for the negative relationship between B7-H4 and B7-H1 in EBV⁺DLBCL. The expression of B7-H1 in EBV⁺DLBCL appears to be the dominant factor which affects tumor aggressiveness. When B7-H1 expression weakens, the molecule B7-H4 may become the dominant factor of prognosis in patients with EBV⁺DLBCL.

A novel tetravalent bispecific antibody targeting programmed death 1 and tyrosine-protein kinase Met for treatment of gastric cancer

Background Redirecting T cells to tumor cells using bispecific antibodies (BsAbs) is emerging as a potent cancer therapy. The main concept of this strategy is to cross-link tumor cells and T cells by simultaneously binding to cell surface tumor-associated antigen (TAA) and the CD3ƹ chain. However, immune checkpoint programmed cell death ligand-1 (PD-L1) on tumor cells or other myeloid cells upreglulated remarkablely after the treatment of CD3-binding BsAbs, leads to the generation of suppressed microenvironment for immune evasion and tumor progression. Although this resistance could be partially reversed by anti-PD-L1 treatment, targeting two pathways through one antibody-based molecule may provide a strategic advantage over the combination of BsAbs and immune checkpoint inhibitors. Methods We developed two novel BsAbs PD-1/c-Met DVD-Ig and IgG-scFv both targeting PD-1 to restore the immune effector function of T cells and engaging them to tumor cells via binding to cellular-mesenchymal to epithelial transition factor (c-Met). Binding activities, T cell activation and proliferation were analyzed by flow cytometry. Cell Cytotoxicity and cytokine release were measured using LDH release assay and ELISA, respectively. Anti-tumor response in vivo was evaluated by generate xenograft models in NOD-SCID mice. Results These bispecific antibodies exhibited effective antitumor activity against high- and low- c-Met-expressing gastric cancer cell lines in vitro and mediated strong tumor growth inhibition in human gastric cancer xenograft models. Conclusion The engagement of the PD-1/PD-L1 blockade to c-Met-overexpressing cancer cells is a promising strategy for the treatment of gastric cancer and potentially other malignancies.

Serum soluble B7-H4 is a prognostic marker for patients with non-metastatic clear cell renal cell carcinoma

Background

B7-H4 is a member of the B7 family of immune-regulatory ligands and is considered to be a negative regulator of the immune response. We investigated the clinical significance of serum soluble B7-H4 in patients with non-metastatic clear cell renal cell carcinoma.

Methods

We analyzed 108 patients in whom non-metastatic clear cell renal cancer was diagnosed at Tokyo Metropolitan Tama Medical Center between 2008 and 2013. We measured the serum soluble B7-H4 level using the Enzyme-Linked ImmunoSorbent Assay (ELISA) and evaluated the association between the peripheral blood neutrophil count and sB7-H4 as well as the utility of soluble B7-H4 as a prognostic biomarker for clear cell renal cancer. The Cox proportional hazards regression model was used to assess the PFS and OS with the soluble B7-H4 level.

Results

We detected high levels of soluble B7-H4 in the sera of 56% of patients with non-metastatic clear cell renal cell carcinoma versus only 10% of healthy donors. Elevated soluble B7-H4 levels were associated with changes in an elevated peripheral blood neutrophil count. The increase of soluble B7-H4 also was significantly associated with poor PFS and OS. Multivariate analysis showed that the elevation of the soluble B7-H4 level was an independent prognostic factor for PFS and OS.

Conclusions

Our data suggest that the association between serum soluble B7-H4 and peripheral blood neutrophil count, as well as the evaluation of serum soluble B7-H4 expression is a useful tool for predicting the prognosis of patients with non-metastatic clear cell renal cell carcinoma.

Co-inhibitory Molecule B7 Superfamily Member 1 Expressed by Tumor-Infiltrating Myeloid Cells Induces Dysfunction of Anti-tumor CD8+ T Cells

The molecular mechanisms whereby CD8⁺ T cells become "exhausted" in the tumor microenvironment remain unclear. Programmed death ligand-1 (PD-L1) is upregulated on tumor cells and PD-1-PD-L1 blockade has significant efficacy in human tumors; however, most patients do not respond, suggesting additional mechanisms underlying T cell exhaustion. B7 superfamily member 1 (B7S1), also called B7-H4, B7x, or VTCN1, negatively regulates T cell activation. Here we show increased B7S1 expression on myeloid cells from human hepatocellular carcinoma correlated with CD8⁺ T cell dysfunction. B7S1 inhibition suppressed development of murine tumors. Putative B7S1 receptor was co-expressed with PD-1 but not T cell immunoglobulin and mucin-domain containing-3 (Tim-3) at an activated state of early tumor-infiltrating CD8⁺ T cells, and B7S1 promoted T cell exhaustion, possibly through Eomes overexpression. Combinatorial blockade of B7S1 and PD-1 synergistically enhanced anti-tumor immune responses. Collectively, B7S1 initiates dysfunction of tumor-infiltrating CD8⁺ T cells and may be targeted for cancer immunotherapy.

Prognostic role of high B7-H4 expression in patients with solid tumors: a meta-analysis

BACKGROUND

Recently, many studies have shown that B7-H4 exhibits altered expression in various cancers. We performed a meta-analysis to evaluate the prognostic role of B7-H4 expression in solid tumors.

RESULTS

Data from 18 observational studies and 2467 patients were summarized. An elevated baseline B7-H4 was significantly associated with worse OS (pooled HR = 1.79; 95% CI = 1.56-2.06). Differences across subgroups of tumor type, patients' ethnicity, analysis type, HR obtain method and cut-off value were not significant (PD = 0.313, PD = 0.716, PD = 0.896, PD = 0.290 and PD = 0.153, respectively). Furthermore, patients with high B7-H4 had a significantly shorter DFS (pooled HR = 2.12; 95%CI = 1.45-3.09).

MATERIALS AND METHODS

We searched PubMed, Embase and the Cochrane Library (last update by November 26, 2015) to identify studies assessing the effect of B7-H4 on survival of cancer patients. Pooled hazard ratios (HRs) for overall survival (OS) and disease-free survival (DFS) were estimated using fixed-effects models and random-effects models respectively.

CONCLUSIONS

This meta-analysis clarified that high B7-H4 expression in tissue was significantly associated with poor survival in patients with solid tumors. Future clinical studies are warranted to determine whether B7-H4 blockade has a favorable effect on disease recurrence and mortality.

Assessment of combined expression of B7-H3 and B7-H4 as prognostic marker in esophageal cancer patients

The co-stimulatory ligands of B7-family have been confirmed to play an important role in negatively regulating the T-cell mediated anti-tumor immunity. In addition, these inhibitory molecules are also aberrantly expressed on various human cancers tissues, and significantly associated with cancer progression and patients' poor prognoses. We have previously reported that B7-H3 and B7-H4 ligands are highly expressed in human esophageal cancer tissues. Herein, we tried to further analyze the value of their combined expression on prognostic prediction for esophageal cancer patients. We found that the combined expression of both B7-H3 and B7-H4 could be used as a valuable risk factor for predicting the prognosis of esophageal cancer patients (P=0.003). Moreover the status of these patients with high expression of both B7-H3 and B7-H4, was positively and significantly associated with the tumor invasion depth (P=0.0414) and TNM stage (P=0.0414). The Cox multivariate proportional hazards regression analysis revealed that the tumor size (P=0.007), the TNM stage (P=0.024) and the status of both B7-H3 and B7-H4 high expression (P=0.011), could be used as an independent risk factor for predicting patients' postoperative prognosis, respectively. In conclusion, our data indicated that the combined application of B7-H3 and B7-H4 expression can be effectively used as a prognostic marker in esophageal cancer patients.

Prognostic significance of B7-H4 expression in matched primary pancreatic cancer and liver metastases

Liver metastasis development in pancreatic cancer patients is common and confers a poor prognosis. Clinical relevance of biomarker analysis in metastatic tissue is necessary. B7-H4 has an inhibitory effect on T cell mediated response and may be involved in tumor development. Although B7-H4 expression has been detected in pancreatic cancer, its expression in liver metastases from pancreatic cancer is still unknown. In this study, overall 43 pancreatic cancer liver metastases (with matched primaries in 15/43 cases) and 57 pancreatic cancer cases without liver metastases or other distant metastases were analyzed for their expression of B7-H4 by immunohistochemistry. Survival curves and log-rank tests were used to test the association of B7-H4 expression with survival. B7-H4 was highly expressed in 28 (65.1%) of the 43 liver metastases and 9 (60.0%) of the 15 matched primary tumors. The expression of B7-H4 in liver metastases was significantly higher than in the matched primary tumors (p < 0.05). Patients with high B7-H4 expression in their primary pancreatic cancer had higher risk of developing liver metastases (p < 0.05). In univariate analysis, B7-H4 expression was significantly associated with the risk of death (p < 0.05). And the multivariate analysis identified that B7-H4 was an independent prognostic indicator (p < 0.05). Our results revealed B7-H4 to be associated with poor prognosis in patients with pancreatic cancer liver metastasis. B7-H4 may promote pancreatic cancer metastasis and was promising to be a potential prognostic indicator of pancreatic cancer.

Nuclear localization of B7-H4 in pulmonary adenocarcinomas presenting as a solitary pulmonary nodule

PURPOSE

Although the pathogenicity of B7-H4 in cancer is well established, its role in pulmonary adenocarcinoma, especially lesions presenting as solitary pulmonary nodules (SPNs), remains unclear.

METHODS

40 cases of pulmonary adenocarcinoma presenting with SPN were enrolled during year 2012-2015. The B7-H4 expression and its subcellular distribution in pulmonary adenocarcinoma presenting with SPN were analyzed by immunohistochemistry, further its correlation with Ki-67 expression and CT feature. In vitro, the B7-H4 expression in the cytoplasmic and nucleus fractions of lung cancer cell lines was determinate by western blotting.

RESULTS

Immunostaining revealed B7-H4 in the cytoplasm of cells from all 40 SPN samples studied. No surface localization of B7-H4 was detected, but in 18 samples the nuclear membranes were B7-H4-positive. Moreover, patients with more poorly differentiated and invasive adenocarcinomas showed greater localization of B7-H4 to the nuclear membrane. The percentage of lesions with ground-glass opacity was significantly greater among samples negative for nuclear membrane B7-H4. Most importantly, there was a statistically significant relationships between the Ki-67 index and B7-H4 positivity of the nuclear membrane. This suggests tumors exhibiting higher nuclear membrane B7-H4 have greater proliferative potential. Western blotting confirmed both cytoplasmic and nuclear B7-H4 localization in lung adenocarcinoma cell lines.

CONCLUSIONS

Taken together, our study provides a new insight into the tumorigenicity of B7-H4 in lung adenocarcinoma. We suggest that in pulmonary adenocarcinoma presenting with SPN, nuclear membrane localization of B7-H4 within the tumor cells is associated with increased malignancy.

Potential targeting of B7-H4 for the treatment of cancer

Observations noting the presence of white blood cell infiltrates within tumors date back more than a century, however the cellular and molecular mechanisms regulating tumor immunity continue to be elucidated. The recent successful use of monoclonal antibodies to block immune regulatory pathways to enhance tumor-specific immune responses for the treatment of cancer has encouraged the identification of additional immune regulatory receptor/ligand pathways. Over the past several years, a growing body of data has identified B7-H4 (VTCN1/B7x/B7S1) as a potential therapeutic target for the treatment of cancer. The potential clinical significance of B7-H4 is supported by the high levels of B7-H4 expression found in numerous tumor tissues and correlation of the level of expression on tumor cells with adverse clinical and pathologic features, including tumor aggressiveness. The biological activity of B7-H4 has been associated with decreased inflammatory CD4⁺ T-cell responses and a correlation between B7-H4-expressing tumor-associated macrophages and FoxP3⁺ regulatory T cells (Tregs) within the tumor microenvironment. Since B7-H4 is expressed on tumor cells and tumor-associated macrophages in various cancer types, therapeutic blockade of B7-H4 could favorably alter the tumor microenvironment allowing for antigen-specific clearance tumor cells. The present review highlights the therapeutic potential of targeting B7-H4.

B7-H4 as an independent prognostic indicator of cancer patients: a meta-analysis

The expression of B7-H4 was observed in a variety of tumors, however the prognostic value in cancer was still controversial. Therefore, we conducted this meta-analysis to explore the potential role of B7-H4 in cancer prognostic prediction. Twenty-seven studies including 3771 patients were brought into the analysis according to the inclusion and exclusion criteria. The pooled results demonstrated that elevated B7-H4 predicted a poor OS (HR = 1.93, 95% CI 1.71-2.18, P < 0.001) and DFS (HR = 1.84, 95% CI 1.46-2.33, P < 0.001). Subgroup analysis showed that races, tumor types, sample sources, analysis types, sources of HR and sample sizes exhibited non-significant distinctions with OS (P_S = 0.878, P_S = 0.143, P_S = 0.613, P_S = 0.639, P_S = 0.48 and P_S = 0.528, respectively). PubMed, Embase and the Cochrane Library were searched up to April 7, 2017, to recognize the available studies for assessing the association between B7-H4 and cancer patients’ outcome. We extracted the hazard ratio (HR), relative ratio (RR), odds ratio (OR) with their 95% confidence interval (CI) for overall survival (OS) or disease-free survival (DFS) as the effect size (ES) for the analysis. This meta-analysis demonstrates high expression of B7-H4 is a negative correlation with the outcome of cancer patients.

Novel B7-H4-mediated crosstalk between human non-Hodgkin lymphoma cells and tumor-associated macrophages leads to immune evasion via secretion of IL-6 and IL-10

Non-Hodgkin lymphoma (NHL) is an incurable lymphoproliferative cancer, and patients with NHL have a poor prognosis. The present study explored the regulatory mechanism of expression and possible roles of the immunosuppressive B7-H4 molecule in human NHL. For functional studies, NHL-reactive T cell lines were generated via the isolation of allogeneic CD3+ T cells from healthy donors and repeated in vitro stimulation with irradiated NHL cells isolated from patients. B7-H4 was found to be distributed in NHL cells and tissues, and its surface protein expression levels were further upregulated by the incubation of NHL cells with interleukin (IL)-6, IL-10, or interferon-γ. Additionally, the supernatants of tumor-associated macrophages (tMφs) upregulated B7-H4 surface expression by producing IL-6 and IL-10. B7-H4 expressed in NHL cells inhibited the cytotoxic activity of NHL-reactive T cells. Conversely, the inhibition of B7-H4 in NHL cells promoted T cell immunity and sensitized NHL cells to cytolysis. Furthermore, tMφs induced B7-H4 promoted NHL cell evasion of the T cell immune response. In conclusion, this study shows that NHL-expressed B7-H4 is an important immunosuppressive factor that inhibits host anti-tumor immunity to NHL. Targeting tumor-expressed B7-H4 may thus provide a new treatment strategy for NHL patients.

Prognostic values of tissue factor and its alternatively splice transcripts in human gastric cancer tissues

We have previously reported that the higher expression of TF in human esophageal cancer tissues was significantly associated with tumor invasion, intratumoral microvessel density and patients' postoperative prognoses. Besides its trans-membranous form, TF also has alternatively spliced transcripts. In the present study, the transcripts of the two TF isoforms, flTF and asTF, in human gastric cancer tissues were determined by real-time PCR, and the correlation between the expression of TF isoforms and patient's clinicopathological features was also analyzed. Our results showed that the relative mRNA expression levels of flTF and asTF in human gastric cancer tissues was significantly higher than those in normal tissues (P=0.035 and P=0.006, respectively). The relative mRNA expression level of asTF was significantly associated with age (P=0.018), meanwhile, we could not find that flTF or asTF expression level was correlated with any other characteristics of the patients, including gender, TNM stage, pathological grade, tumor size, histological type, or chemotherapy sensitivity. Univariate analysis demonstrated that the overall survival rate of gastric cancer patients with lower flTF or asTF expression level was greater than those with higher expression level (P=0.018 and =0.038, respectively). Multivariate COX model analysis also demonstrated that flTF expression (P=0.048) or asTF expression (P=0.002) could be used as independent prognostic predictors in human gastric cancer. Thus, both flTF and asTF mRNA expression levels in cancer tissues could be used as useful risk factors for evaluating the prognoses of patients suffering from gastric cancer.

Targeting the PD-1 pathway: a new hope for gastrointestinal cancers

BACKGROUND

VEGF, HER2 and EGFR targeted agents are currently used in gastric, esophageal and colorectal cancers. However, treatment outcomes are still poor in most gastrointestinal (GI) cancers. Immune checkpoints are one of the most promising immunotherapy approaches. In this review article, we aim to discuss the efficacy and safety of anti-PD-1/PD-L1 therapies in GI cancers, including gastric, esophageal and colorectal cancer in published or reported recent studies.

SCOPE

A literature search was made from PubMed and ASCO Annual Meeting abstracts by using the following search keywords: "nivolumab", "pembrolizumab", "avelumab", "GI cancers" "anti-PD1 therapy" and "anti-PD-L1 therapy". The last search was on 2 November 2016. The most important limitation of our review is that most of the data on anti-PD-1/PD-L1 therapies in GI cancers relies on phase 1 and 2 trials.

FINDINGS

Currently, there are two anti-PD-1 (nivolumab and pembrolizumab) and one anti-PDL1 (atezolizumab) agents approved by FDA. After the treatment efficacy of immune checkpoint blockade was shown in melanoma, renal cell cancer and non-squamous lung cancer, trials which evaluate immune checkpoint blockade in GI cancers are ongoing. Early results of trials have been promising and encouraging for patients with advanced stage gastroesophageal cancer. According to early results of published trials, response to anti-PD1/PD-L1 agents appears to be associated with tumor PD-L1 levels. According to two recently published phase 2 trials, the clinical benefits of immune checkpoint blockade with both nivolumab and pembrolizumab were limited in patients with microsatellite instability (MSI) positive advanced colorectal cancer. However, several phase 2/3 trials are still ongoing.

CONCLUSION

Both pembrolizumab and nivolumab show promising efficacy with acceptable safety data in published trials in GI cancers, especially in refractory MSI positive metastatic colorectal cancer.

Molecular Pathways: Evaluating the Potential for B7-H4 as an Immunoregulatory Target

With the clinical success of CTLA-4 and PD-1 blockade in treating malignancies, there is tremendous interest in finding new ways to augment antitumor responses by targeting other inhibitory molecules. In this review, we describe one such molecule. B7-H4, a member of the B7 family of immunoregulatory proteins, inhibits T cell proliferation and cytokine production through ligation of an unknown receptor expressed by activated T cells. Notably, B7-H4 protein expression is observed in a high proportion of patients' tumors across a wide variety of malignancies. This high expression by tumors in combination with its low or absent protein expression in normal tissues makes B7-H4 an attractive immunotherapeutic target. Preclinical investigation into B7-H4-specific chimeric antigen receptor (CAR) T cells, antibody-mediated blockade of B7-H4, and anti-B7-H4 drug conjugates has shown antitumor efficacy in mouse models. The first clinical trials have been completed to assess the safety and efficacy of a B7-H4 fusion protein in ameliorating rheumatoid arthritis. Clin Cancer Res; 23(12); 2934-41. ©2017 AACR.

B7-H4 is Predictive of Poor Prognosis in Patients with Gastric Cancer

Background

Recently, some studies were performed to evaluate the relevance of B7-H4 and gastric cancer (GC) prognosis. However, the results remained controversial. Therefore, we performed the present meta-analysis.

Material/Methods

We performed a systematic search in PubMed and Web of Science databases. All data were extracted and reviewed from each eligible study independently by 2 investigators. The strength of association between B7-H4 and GC prognosis was assessed by computing odds ratio (OR) with its corresponding 95% confidence interval (CI).

Results

Six studies that evaluated the association between B7-H4 and GC prognosis were included. The results showed a statistically significant association of B7-H4 and GC prognosis (OR=1.63, 95%CI=1.30–2.03). Furthermore, we conducted subgroup analysis based on source of B7-H4; the results from blood (OR=1.71; 95%CI, 1.09–2.68) and tissue (OR=1.60; 95%CI, 1.03–2.07) indicated B7-H4 was significantly associated with poor prognosis.

Conclusions

This meta-analysis suggests that GC patients with high B7-H4 have poor prognosis.

B7-H4 expression indicates poor prognosis of oral squamous cell carcinoma

Checkpoint blockade therapy utilizing monoclonal antibodies to reactivate T cells and recover their antitumor activity makes an epoch in cancer immunotherapy. The role of B7-H4, a novel negative immune checkpoint, in oral squamous cell carcinoma (OSCC) has still not been elucidated. In this study, tissue samples from human OSCC, which contains 165 primary OSCC, 48 oral epithelial dysplasia and 43 normal oral mucosa specimens, and Tgfbr1/Pten 2cKO mice OSCC model were stained with B7-H4 antibody to analyze the correlations between B7-H4 expression and clinicopathological characteristics. Kaplan-Meier analysis was used to compare the survival of patients with high B7-H4 expression and patients with low B7-H4 expression. We found B7-H4 is highly expressed in human OSCC tissue, and the B7-H4 expression level was associated with the clinicopathological parameters containing pathological grade and lymph node status. Moreover, we confirmed that B7-H4 was overexpressed in Tgfbr1/Pten 2cKO mice OSCC model. Our data also indicated that patients with high B7-H4 expression had poor overall survival compared with those with low B7-H4 expression. Furthermore, this study demonstrated that B7-H4 was positively associated with PD-L1, CD11b, CD33, PI3Kα p110, and p-S6 (S235/236). Taken together, these findings suggest B7-H4 is a potential target in the treatment of OSCC.

Diagnosis value of serum soluble B7-H4 expression in non-small cell lung cancer

INTRODUCTION

B7-H4, a member of the inhibitory B7 family, can restrain T cell proliferation, activation, cytokine secretion, and may be involved in immune evasion in cancer patients.

OBJECTIVES

This aim of the study was to determine the expression level of soluble B7-H4 (sB7-H4) in circulation and to subsequently evaluate the clinical significance of circulating sB7-H4 in patients with non-small cell lung cancer (NSCLC).

METHODS

Serum specimens from 128 patients with NSCLC, 100 healthy volunteers (HV), and 80 patients with benign lung diseases (BLD) were collected. The concentrations of sB7-H4 were measured by sandwich enzyme-linked immunosorbent assay.

RESULTS

Serum sB7-H4 levels in patients with NSCLC were significantly higher than those in patients with BLD (P < 0.05), or those in HV (P < 0.05). Using a cutoff of 27.8 ng/mL, the sensitivity and specificity of sB7-H4 in differentiating between patients with NSCLC and patients with BLD, and between patients with NSCLC and HV was, 46.9% and 92.5%, and 54.7% and 95.0%, respectively. An area under the curve (AUC) for NSCLC resulting from sB7-H4 (0.863), which was significantly better than any other tumour markers tested including CA125 (0.763), and CEA (0.775).

CONCLUSION

In conclusion, assessment of serum sB7-H4 levels could be considered as a diagnostic biomarker for NSCLC.

Evaluation of serum and pleural levels of soluble B7-H4 in lung cancer patients with pleural effusion

OBJECTIVE

To evaluate the diagnostic value of sB7-H4 and CEA in both serum and pleural effusion of lung cancer patients.

METHODS

Levels of sB7-H4 and CEA in 90 patients with malignant pleural effusion due to lung cancer and 58 patients with benign pleural effusion were measured by ELISA.

RESULTS

The sB7-H4 and CEA levels in pleural effusion, serum and their ratio (F/S) were higher in lung cancer group than that in benign group (p < 0.01). The diagnostic efficiency of sB7-H4 combined CEA was superior to either sB7-H4 or CEA.

CONCLUSIONS

Measurement of sB7-H4 and CEA might be useful diagnostic value for malignant effusion.

The emerging role of immunotherapy in gastric and esophageal adenocarcinoma

Gastric and esophageal adenocarcinomas are aggressive malignancies. Systemic therapy for these tumors relies primarily on cytotoxic chemotherapy but outcomes remain poor. In recent years, immunotherapy has emerged as a new, promising therapeutic approach for a variety of solid tumors. Characterization of gastroesophageal cancers has revealed genomic and immune features of these tumors that may predict response to immunotherapy. Indeed, preliminary results from the initial trials of immune checkpoint inhibitors have been encouraging, with objective response rates of 20% in heavily pretreated patient populations. Based on these results, additional trials of single-agent checkpoint inhibitors as well as combinations with chemotherapy and targeted therapies are currently ongoing. Further work to identify predictive biomarkers will be crucial for the successful implementation of immunotherapy.

Antibody Therapies in Cancer

Antibody-based immunotherapy has become a standard treatment for a variety of cancers. Many well-developed antibodies disrupt signaling of various growth factor receptors for the treatment of a number of cancers by targeting surface antigens expressed on tumor cells. In recent years, a new family of antibodies is currently emerging in the clinic, which target immune cells rather than cancer cells. These immune-targeted therapies strive to augment antitumor immune responses by antagonizing immunosuppressive pathways or providing exogenous immune-activating stimuli, which have achieved dramatic results in several cancers. The future of cancer therapies is likely to combine these approaches with other treatments, including conventional therapies, to generate more effective treatments.

Emerging targets in cancer immunotherapy: beyond CTLA-4 and PD-1

Manipulation of co-stimulatory or co-inhibitory checkpoint proteins allows for the reversal of tumor-induced T-cell anergy observed in cancer. The field has gained credence given success with CTLA-4 and PD-1 inhibitors. These molecules include immunoglobulin family members and the B7 subfamily as well as the TNF receptor family members. PD-L1 inhibitors and LAG-3 inhibitors have progressed through clinical trials. Other B7 family members have shown promise in preclinical models. TNFR superfamily members have shown variable success in preclinical and clinical studies. As clinical investigation in tumor immunology gains momentum, the next stage becomes learning how to combine checkpoint inhibitors and agonists with each other as well as with traditional chemotherapeutic agents.

Combination cancer immunotherapy and new immunomodulatory targets

Targeting immune checkpoints such as programmed cell death protein 1 (PD1), programmed cell death 1 ligand 1 (PDL1) and cytotoxic T lymphocyte antigen 4 (CTLA4) has achieved noteworthy benefit in multiple cancers by blocking immunoinhibitory signals and enabling patients to produce an effective antitumour response. Inhibitors of CTLA4, PD1 or PDL1 administered as single agents have resulted in durable tumour regression in some patients, and combinations of PD1 and CTLA4 inhibitors may enhance antitumour benefit. Numerous additional immunomodulatory pathways as well as inhibitory factors expressed or secreted by myeloid and stromal cells in the tumour microenvironment are potential targets for synergizing with immune checkpoint blockade. Given the breadth of potential targets in the immune system, critical questions to address include which combinations should move forward in development and which patients will benefit from these treatments. This Review discusses the leading drug targets that are expressed on tumour cells and in the tumour microenvironment that allow enhancement of the antitumour immune response.

Immunotherapy for advanced gastric and esophageal cancer: preclinical rationale and ongoing clinical investigations

Gastric and esophageal cancers represent a major global cancer burden and novel approaches are needed. Despite recent improvements in outcomes with trastuzumab and ramucirumab the prognosis for advanced disease remains poor, with a median overall survival of 1 year. Comprehensive genomic characterization has defined molecular subgroups and potentially actionable genomic alterations, but the majority of patients do not yet benefit from molecularly directed therapies. Breakthroughs in immune checkpoint blockade have provided new therapeutic avenues in melanoma, and continue to expand into other tumor types, with ongoing investigations in gastrointestinal (GI) malignancies. The frequency of programmed death ligand 1 (PD-L1) overexpression, a putative response biomarker, approaches forty percent in gastric cancers. Translational studies and molecular classification suggest gastric and esophageal cancers are candidate malignancies for immune checkpoint inhibition trials and early clinical data is promising. Here we review the mechanisms, preclinical, and early clinical data supporting the role for immune checkpoint blockade in gastric and esophageal cancer.

Inhibitory receptors as targets for cancer immunotherapy

Inhibitory receptors expressed on T cells control immune responses while limiting autoimmunity. However, tumors can hijack these "checkpoints" for protection from immune attack. Tumor-specific T cells that exhibit an exhausted, unresponsive phenotype express high levels of inhibitory receptors including CTLA4, PD1, and LAG3, among others. Intratumoral regulatory T cells promote immunosuppression and also express multiple inhibitory receptors. Overcoming this inhibitory receptor-mediated immune tolerance has thus been a major focus of recent cancer immunotherapeutic developments. Here, we review how boosting the host's immune system by blocking inhibitory receptor signaling with antagonistic mAbs restores the capacity of T cells to drive durable antitumor immune responses. Clinical trials targeting the CTLA4 and PD1 pathways have shown durable effects in multiple tumor types. Many combinatorial therapies are currently being investigated with encouraging results that highlight enhanced antitumor immunogenicity and improved patient survival. Finally, we will discuss the ongoing identification and dissection of novel T-cell inhibitory receptor pathways, which could lead to the development of new combinatorial therapeutic approaches.

A Systematic Review of Immunotherapy in Urologic Cancer: Evolving Roles for Targeting of CTLA-4, PD-1/PD-L1, and HLA-G

CONTEXT

Overexpression of immune checkpoint molecules affects tumor-specific T-cell immunity in the cancer microenvironment, and can reshape tumor progression and metastasis. Antibodies targeting checkpoints could restore antitumor immunity by blocking the inhibitory receptor-ligand interaction.

OBJECTIVE

To analyze data and current trends in immune checkpoint targeting therapy for urologic cancers.

EVIDENCE ACQUISITION

Systematic literature search for clinical trials in the PubMed and Cochrane databases up to August 2014 according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Endpoints included oncologic results, tumor response rates, safety, and tolerability.

EVIDENCE SYNTHESIS

Anti-CTLA-4 monotherapy has demonstrated biochemical responses in prostate cancer. One phase 3 trial assessing ipilimumab efficacy in castration-resistant disease was negative overall. Nevertheless, ipilimumab may significantly improve overall survival compared with placebo in subgroups of patients with favorable prognostic features. In renal cancer, phase 1 trials showed interesting stabilization or long-lasting objective response rates approaching 50% using anti-PD-1/PD-L1 drugs in heavily pretreated metastatic patients. In bladder cancer, one phase 2 trial indicated a good safety profile for ipilimumab as a neoadjuvant drug before radical cystectomy. Overall, immune-related effects such as colitis and dermatitis were common and well tolerated.

CONCLUSIONS

Our systematic review shows that antibodies blocking immune checkpoints offer interesting and long-lasting response rates in heavily pretreated patients with advanced urologic cancers. More promising results are currently provided by anti-CTLA-4 antibodies in prostate cancer and by PD-1/PD-L1 inhibitors in renal cancer. These should encourage new clinical trials of immune therapy combinations and immunotherapy monotherapy combined with conventional anticancer drugs. In bladder cancer, the use of targeted immunotherapy still remains underevaluated; however, preliminary results reported at recent conferences seem encouraging.

PATIENT SUMMARY

Data from studies support the activity and safety of immune checkpoint inhibitors in urologic cancers, alone or in combination with conventional cancer therapies. Encouraging data in other oncologic fields could translate into interesting responses in urological cancers.

Prognostic value of soluble H7-B4 in pleural effusion associated with lung cancer

B7-H4, a member of the inhibitory B7 family, can restrain T cell proliferation, activation, and cytokine secretion and may be involved in immune evasion in cancer patients. This study aimed to evaluate the diagnostic and prognostic value of pleural effusion levels of soluble B7-H4 (sB7-H4) in lung cancer patients with malignant pleural effusion (MPE). Pleural effusion samples were collected from 98 lung cancer patients with malignant effusion and from 60 patients with nonmalignant pleural effusion. Pleural effusion concentrations of sB7-H4 were measured using sandwich enzyme-linked immunosorbent assay. Malignant effusion exhibited higher sB7-H4 levels than those in nonmalignant effusion (P < 0.01). Lung cancer patients with pleural effusion sB7-H4 levels below 35.8 ng/ml had a longer overall survival than those with higher levels (P < 0.05). By multivariate analysis, pleural effusion sB7-H4 was an independent prognostic factor in patients with MPE. In conclusion, measurement of sB7-H4 might be a useful diagnostic and prognostic value for MPE patients.

The evolution of checkpoint blockade as a cancer therapy: what's here, what's next?

Unleashing the immune system to fight cancer has become one of the main treatment modalities since the anti-CTLA-4 antibody, ipilimumab was approved for patients with advanced melanoma in 2011. Pembrolizumab and nivolumab, two anti-PD-1 antibodies recently approved for the treatment of patients with metastatic melanoma, are being actively investigated for the treatment of multiple caners including lung, breast, bladder and renal cancers along with other anti-PD-1/L1 antibodies. Early results of combining of anti-CTLA-4 antibody and anti-PD-1 antibody treatment for advanced melanoma patients are showing impressive response rates with manageable toxicity profiles. There are several other checkpoint molecules that are likely potential inhibitory targets. The outcome of blocking some of these negative immune regulators, such as LAG-3 or TIM-3, is being pursued in the clinic or about to enter clinical development. Blockade of these molecules is demonstrating promising preclinical activity alone or when combined with anti-PD-1/L1. Future studies will define bio-markers of these therapies and how to target them alone or in combination with other immunotherapies, chemotherapy, radiotherapy and small molecule inhibitors.

Isolation and Validation of Anti-B7-H4 scFvs from an Ovarian Cancer scFv Yeast-Display Library

B7-H4 (VTCN1, B7x, B7s) is an inhibitory modulator of T-cell response implicated in antigen tolerization. As such, B7-H4 is an immune checkpoint of potential therapeutic interest. To generate anti-B7-H4 targeting reagents, we isolated antibodies by differential cell screening of a yeast-display library of recombinant antibodies (scFvs) derived from ovarian cancer patients and we screened for functional scFvs capable to interfere with B7-H4-mediated inhibition of antitumor responses. We found one antibody binding to B7-H4 that could restore antitumor T cell responses. This chapter gives an overview of the methods we developed to isolate a functional anti-B7-H4 antibody fragment.

B7-H4 expression by nonhematopoietic cells in the tumor microenvironment promotes antitumor immunity

The B7 family plays a critical role in both positive and negative regulation of immune responses by engaging a variety of receptors on lymphocytes. Importantly, blocking coinhibitory molecules using antibodies specific for CTLA-4 and PD-1 enhances tumor immunity in a subset of patients. Therefore, it is critical to understand the role of different B7 family members since they may be suitable therapeutic targets. B7-H4 is another member that inhibits T-cell function, and it is also upregulated on a variety of tumors and has been proposed to promote tumor growth. Here, we investigate the role of B7-H4 in tumor development and show that B7-H4 expression inhibits tumor growth in two mouse models. Furthermore, we show that B7-H4 expression is required for antitumor immune responses in a mouse model of mammary tumorigenesis. We found that the expression levels of B7-H4 correlate with MHC class I expression in both mouse and human samples. We show that IFNγ upregulates B7-H4 expression on mouse embryo fibroblasts and that the upregulation of B7-H4 on tumors is dependent on T cells. Notably, patients with breast cancer with increased B7-H4 expression show a prolonged time to recurrence. These studies demonstrate a positive role for B7-H4 in promoting antitumor immunity.

Structure and cancer immunotherapy of the B7 family member B7x

B7x (B7-H4 or B7S1) is a member of the B7 family that can inhibit T cell function. B7x protein is absent in most normal human tissues and immune cells, but it is overexpressed in human cancers and often correlates with negative clinical outcome. The expression pattern and function of B7x suggest that it may be a potent immunosuppressive pathway in human cancers. Here, we determined the crystal structure of the human B7x immunoglobulin variable (IgV) domain at 1.59 Å resolution and mapped the epitopes recognized by monoclonal antibodies. We developed an in vivo system to screen therapeutic monoclonal antibodies against B7x and found that the clone 1H3 significantly inhibited growth of B7x-expressing tumors in vivo via multiple mechanisms. Furthermore, the surviving mice given 1H3 treatment were resistant to tumor rechallenge. Our data suggest that targeting B7x on tumors is a promising cancer immunotherapy and humanized 1H3 may be efficacious for immunotherapy of human cancers.

T cells and costimulation in cancer

Optimal T cell response is dependent not only on T cell receptor activation, but also on additional signaling from coreceptors. The main coreceptors include B7 and tumor necrosis factor family members. They exert costimulatory or coinhibitory effects, and their balance determines the fate of T cell response. In normal conditions, costimulators facilitate the development of protective immune response, whereas coinhibitors dampen inflammation to avoid organ/tissue damage from excessive immune reaction. In the tumor microenvironment, the balance is garbled: inhibitory pathways predominate, and T cell response is impaired. The importance of cosignaling in the tumor immune response has been experimentally and clinically demonstrated. New therapeutic strategies targeting T cell cosignaling, especially coinhibitory molecules, are under active experimental and clinical investigation. This review summarizes the functions of main T cell cosignaling axes and discusses their clinical application.

Evaluation of tumor response to cytokine-induced killer cells therapy in malignant solid tumors

CIK cells therapy has been evaluated as an adoptive cell immunotherapy for cancer patients, but there still have not been any standardized systems for evaluating the antitumor efficacy yet. The WHO and RECIST criteria have already been established for a few years but not sufficient to fully characterize the activity of immunotherapy. Based on these two criteria, the irRC was proposed for evaluating the efficacy of immunotherapy. A variety of bioassays for immune monitoring including the specific and non-specific methods, have been established. We recommend detect levels of various immunocytes, immune molecules and soluble molecules to find the correlations among them and clinicopathological characteristics to establish criteria for immunological classification. We also recommend a paradigm shift for the oncologists in the evaluation of immune therapies to ensure assessment of activity based on clinically relevant criteria and time points.

Serum B7-H4 expression is a significant prognostic indicator for patients with gastric cancer

Background

B7-H4 is a novel B7 ligand that plays an important role in the T cell-mediated immune response as a negative regulator. Previous studies have suggested the aberrant expression of membrane B7-H4 in tumor cells. The aim of this study is to determine the expression levels of preoperative soluble B7-H4 (sB7-H4) in circulation and to investigate the correlations between sB7-H4 levels and clinicopathological parameters as well as the survival rate of patients with gastric cancer.

Methods

Blood specimens from 132 patients with gastric cancer and 63 healthy volunteers were analyzed by sandwich enzyme-linked immunosorbent assay.

Results

Median concentrations of sB7-H4 in patients with gastric cancer were significantly higher than those in healthy volunteers (16.85 versus 10.46 ng/mL; P = 0.008). Median levels of sB7-H4 were significantly correlated with tumor size, lymph node metastasis, the depth of tumor invasion and tumor-node-metastasis classification (P = 0.002, P = 0.001, P = 0.041 and P <0.001, respectively), but not with sex, age, tumor location or histological subtype (all P >0.05). Additionally, the overall survival rate was significantly lower in patients with high sB7-H4 levels when compared with low sB7-H4 levels (50.0% versus 77.3%, χ² = 10.78, P = 0.001). Moreover, multivariate analysis demonstrated that the risk of death was significantly higher in patients with high sB7-H4 levels than in those with low sB7-H4 levels (P = 0.039).

Conclusions

sB7-H4 is a valuable blood marker for predicting the progression and prognosis of patients with gastric cancer.

Expression of costimulatory molecules B7-H1, B7-H4 and Foxp3+ Tregs in gastric cancer and its clinical significance

OBJECTIVE

Immune escape plays an important role in tumor progression. In the present study, the expression of B7-H1, B7-H4 and Foxp3 involved in immune escape in gastric carcinoma was investigated and the corresponding clinical significance was evaluated.

METHODS

Immunohistochemistry was used to detect the expression of B7-H1, B7-H4 and Foxp3 in 100 gastric cancer specimens, and 30 paracarcinoma tissues were used as the control.

RESULTS

Both B7-H1 and B7-H4 showed high expression levels in gastric cancer tissues (65.0 and 71.0 %, respectively), and the expressions of B7-H1 and B7-H4 were positively correlated with the depth of tumor invasion, lymph node metastasis and American Joint Committee on Cancer (AJCC) stage (P < 0.05). The number of Foxp3(+) Tregs was much higher in gastric cancer tissues than control tissues, which was positively correlated with lymph node metastasis (P < 0.05). Similarly, a positive correlation between B7-H1 or B7-H4 expression and the number of Foxp3(+) Tregs was observed. The median overall survival rate of patients with high expression of B7-H1, B7-H4 and Foxp3 was significantly poorer than that of patients with low expression of these proteins (P < 0.05). Cox regression multivariate analysis confirmed that lymph node metastasis, AJCC stage, and B7-H1 and Foxp3 overexpression were independent prognostic factors.

CONCLUSION

B7-H1, B7-H4 and Foxp3 were overexpressed in gastric cancer tissues. B7-H1 and Foxp3 are negative prognostic factors for patients with gastric cancer.