B7-H3 is expressed in human hepatocellular carcinoma and is associated with tumor aggressiveness and postoperative recurrence

New Emerging Targets in Cancer Immunotherapy: The Role of B7-H3

Immune checkpoints (ICs) are molecules implicated in the fine-tuning of immune response via co-inhibitory or co-stimulatory signals, and serve to secure minimized host damage. Targeting ICs with various therapeutic modalities, including checkpoint inhibitors/monoclonal antibodies (mAbs), antibody-drug conjugates (ADCs), and CAR-T cells has produced remarkable results, especially in immunogenic tumors, setting a paradigm shift in cancer therapeutics through the incorporation of these IC-targeted treatments. However, the large proportion of subjects who experience primary or secondary resistance to available IC-targeted options necessitates further advancements that render immunotherapy beneficial for a larger patient pool with longer duration of response. B7-H3 (B7 Homolog 3 Protein, CD276) is a member of the B7 family of IC proteins that exerts pleiotropic immunomodulatory effects both in physiologic and pathologic contexts. Mounting evidence has demonstrated an aberrant expression of B7-H3 in various solid malignancies, including tumors less sensitive to current immunotherapeutic options, and has associated its expression with advanced disease, worse patient survival and impaired response to IC-based regimens. Anti-B7-H3 agents, including novel mAbs, bispecific antibodies, ADCs, CAR-T cells, and radioimmunotherapy agents, have exhibited encouraging antitumor activity in preclinical models and have recently entered clinical testing for several cancer types. In the present review, we concisely present the functional implications of B7-H3 and discuss the latest evidence regarding its prognostic significance and therapeutic potential in solid malignancies, with emphasis on anti-B7-H3 modalities that are currently evaluated in clinical trial settings. Better understanding of B7-H3 intricate interactions in the tumor microenvironment will expand the oncological utility of anti-B7-H3 agents and further shape their role in cancer therapeutics.

Evaluation of affinity matured Affibody molecules for imaging of the immune checkpoint protein B7-H3

B7-H3 (CD276), an immune checkpoint protein, is a promising molecular target for immune therapy of malignant tumours. Sufficient B7-H3 expression level is a precondition for successful therapy. Radionuclide molecular imaging is a powerful technique for visualization of expression levels of molecular targets in vivo. Use of small radiolabelled targeting proteins would enable high-contrast radionuclide imaging of molecular targets if adequate binding affinity and specificity of an imaging probe could be provided. Affibody molecules, small engineered affinity proteins based on a non-immunoglobulin scaffold, have demonstrated an appreciable potential in radionuclide imaging. Proof-of principle of radionuclide visualization of expression levels of B7-H3 in vivo was demonstrated using the [99mTc]Tc-AC12-GGGC Affibody molecule. We performed an affinity maturation of AC12, enabling selection of clones with higher affinity. Three most promising clones were expressed with a -GGGC (triglycine-cysteine) chelating sequence at the C-terminus and labelled with technetium-99m (99mTc). 99mTc-labelled conjugates bound to B7-H3-expressing cells specifically in vitro and in vivo. Biodistribution in mice bearing B7-H3-expressing SKOV-3 xenografts demonstrated improved imaging properties of the new conjugates compared with the parental variant [99mTc]Tc-AC12-GGGC. [99mTc]Tc-SYNT-179 provided the strongest improvement of tumour-to-organ ratios. Thus, affinity maturation of B7-H3 Affibody molecules could improve biodistribution and targeting properties for imaging of B7-H3-expressing tumours.

Global research trends on B7-H3 for cancer immunotherapy: A bibliometric analysis (2012-2022)

Immunotherapy has revolutionized cancer treatment. B7-H3 is a promising target for cancer immunotherapy (CI). The present study aimed to utilize bibliometric methods to assess the current research status and explore future trends in the use of B7-H3 for CI. We collected publications related to B7-H3/CI from the Clarivate Web of Science Core Collection database. VOSviewer, Microsoft Excel, the bibliometrix R package, and an online platform were used to conduct qualitative and visualized analyses of the literature. A total of 555 papers were analyzed, revealing a significant increase in annual publications since 2018. The most productive countries were China and the USA, and the leading institutions were Soochow University and Sichuan University. Zang and Ferrone were the most popular authors. Among the journals, Frontiers in Immunology had the highest number of papers, whereas Clinical Cancer Research was the most influential. Historical citation analysis reveals the development of B7-H3/CI. Top-cited papers and keyword analyses were performed to highlight current hotspots in the domain. Using cluster analysis, we classified all keywords into four clusters: "immunotherapy," "co-stimulatory molecule," "B7 family," and "PD-L1." Finally, Trends analysis suggested that future research might focus on "chimeric antigen receptor," "pathways," and "targeting B7-H3." This is the first bibliometric crosstalk analysis between B7-H3 and CI. Our study illustrates that the topic of B7-H3/CI is very popular and has great clinical implications and that the number of correlative publications will continue to increase. B7-H3-based CI may lead to new research trends.

IgG-based B7-H3xCD3 bispecific antibody for treatment of pancreatic, hepatic and gastric cancer

T cell-based immunotherapy has significantly improved treatment options for many malignancies. However, despite these and other therapeutic improvements over the last decades, gastrointestinal cancers, in particular pancreatic, hepatic and gastric cancer, are still characterized by high relapse rates and dismal prognosis, with an accordingly high unmet medical need for novel treatment strategies. We here report on the preclinical characterization of a novel bispecific antibody in an IgG-based format termed CC-3 with B7-H3xCD3 specificity. In many cancer entities including pancreatic, hepatic and gastric cancers, B7-H3 (CD276) is overexpressed on tumor cells and also on the tumor vasculature, the latter allowing for improved access of immune effector cells into the tumor site upon therapeutic targeting. We demonstrate that CC-3 induces profound T cell reactivity against various pancreatic, hepatic and gastric cancer cell lines as revealed by analysis of activation, degranulation and secretion of IL2, IFNγ as well as perforin, resulting in potent target cell lysis. Moreover, CC-3 induced efficient T cell proliferation and formation of T cell memory subsets. Together, our results emphasize the potential of CC-3, which is presently being GMP-produced to enable clinical evaluation for treatment of pancreatic, hepatic and gastric cancer.

Immune checkpoint of B7-H3 in cancer: from immunology to clinical immunotherapy

Immunotherapy for cancer is a rapidly developing treatment that modifies the immune system and enhances the antitumor immune response. B7-H3 (CD276), a member of the B7 family that plays an immunoregulatory role in the T cell response, has been highlighted as a novel potential target for cancer immunotherapy. B7-H3 has been shown to play an inhibitory role in T cell activation and proliferation, participate in tumor immune evasion and influence both the immune response and tumor behavior through different signaling pathways. B7-H3 expression has been found to be aberrantly upregulated in many different cancer types, and an association between B7-H3 expression and poor prognosis has been established. Immunotherapy targeting B7-H3 through different approaches has been developing rapidly, and many ongoing clinical trials are exploring the safety and efficacy profiles of these therapies in cancer. In this review, we summarize the emerging research on the function and underlying pathways of B7-H3, the expression and roles of B7-H3 in different cancer types, and the advances in B7-H3-targeted therapy. Considering different tumor microenvironment characteristics and results from preclinical models to clinical practice, the research indicates that B7-H3 is a promising target for future immunotherapy, which might eventually contribute to an improvement in cancer immunotherapy that will benefit patients.

NK cell immunometabolism as target for liver cancer therapy

Natural killer (NK) cells are being used effectively as a potential candidate in tumor immunotherapy. However, the migration and transport of NK cells to solid tumors is inadequate. NK cell dysfunction, tumor invasiveness, and metastasis are associated with altered metabolism of NK cells in the liver cancer microenvironment. However, in liver cancers, metabolic impairment of NK cells is still not understood fully. Evidence from various sources has shown that the interaction of NK cell's immune checkpoints with its metabolic checkpoints is responsible for the regulation of the development and function of these cells. How immune checkpoints contribute to metabolic programming is still not fully understood, and how this can be beneficial needs a better understanding, but they are emerging to be incredibly compelling to rebuilding the function of NK cells in the tumor. It is expected to represent a potential aim that focuses on improving the efficacy of therapies based on NK cells for treating liver cancer. Here, the recent advancements made to understand the NK cell's metabolic reprogramming in liver cancer have been summarized, along with the possible interplay between the immune and the metabolic checkpoints in NK cell function. Finally, an overview of some potential metabolic-related targets that can be used for liver cancer therapy treatment has been presented.

GPC3-targeted CAR-T cells secreting B7H3-targeted BiTE exhibit potent cytotoxicity activity against hepatocellular carcinoma cell in the in vitro assay

Hepatocellular carcinoma (HCC), the most common primary liver cancer has a high mortality in China, and it is usually diagnosed at a late stage, thereby leaving patients with few effective treatment options. Chimeric antigen receptor-T (CAR-T) cell therapy, a novel immunotherapy that has shown promising results in leukemia, lymphoma and multiple myeloma, is also expected to work well in solid tumors, including HCC. However, the ideal therapeutic efficacy has not yet been achieved, in part due to tumor antigen escape caused by antigen heterogeneity. To overcome such challenge, we screened a panel of biomarkers in HCC cell lines and found that GPC3 and B7H3 were highly expressed on HCC with expression heterogeneity. Then we developed a novel bispecific T cell engagers CAR-T (CAR.T-BiTEs) that drives the expression of a CAR specific for GPC3 and BiTEs against CD3 and B7H3, herein referred to as “GPC3-BiTE CAR.” We found that BiTEs promoted the increased activation of untransduced T cells and IFN-γ release. Moreover, BiTEs secreted by GPC3-BiTE CAR-HEK293T cells promoted increased cytotoxicity activity of untransduced T cells against GPC3+/B7H3+ (GPC3 positive/B7H3 positive) and GPC3-/B7H3+(GPC3 negative/B7H3 positive) HCC cell lines. In vitro function assays showed that GPC3-BiTE CAR-T cells exhibited greater cytotoxicity activity against GPC3+/B7H3+ HCC cell lines than GPC3 CAR-T cells (GPC3-targeted CAR-T cells) and B7H3 CAR-T cells (B7H3-targeted CAR-T cells). Furthermore, GPC3-BiTE CAR-T cells exhibited superior cytotoxicity against GPC3 negative HCC cell lines compared with GPC3 CAR T cells. In conclusion, our study showed that GPC3-BiTE CAR T cells exhibited superior antitumor activity than single-target CAR-T cells and can overcome tumor escape induced by antigen heterogeneity, suggesting that this could be a promising therapeutic strategy for HCC.

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The expression of GPC3 and B7H3 was heterogeneous in HCC tissues.

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BiTEs enhanced the cytotoxicity of untransduced T cells against HCC cell lines.

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GPC3-BiTE CAR-T cells showed enhanced cytotoxicity against GPC3+/B7H3+ cells.

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GPC3-BiTE CAR-T cells can resist GPC3 antigen escape in the in vitro assay.

Evaluation of an Affibody-Based Binder for Imaging of Immune Check-Point Molecule B7-H3

Radionuclide molecular imaging could provide an accurate assessment of the expression of molecular targets in disseminated cancers enabling stratification of patients for specific therapies. B7-H3 (CD276) is a transmembrane protein belonging to the B7 superfamily. This protein is overexpressed in different types of human malignancies and such upregulation is generally associated with a poor clinical prognosis. In this study, targeting properties of an Affibody-based probe, AC12, containing a -GGGC amino acid sequence as a chelator (designated as AC12-GGGC) labelled with technetium-99m (99mTc) were evaluated for imaging of B7-H3-expressing tumours. AC12-GGGC was efficiently labelled with 99mTc. [99mTc]Tc-AC12-GGGC bound specifically to B7-H3 expressing cells in vitro with affinities in nanomolar range. In mice bearing B7-H3-expressing xenografts, [99mTc]Tc-AC12-GGGC showed tumour uptake of 2.1 ± 0.5 %ID/g at 2 h after injection. Its clearance from blood, normal organs and tissues was very rapid. This new targeting agent, [99mTc]Tc-AC12-GGGC, provided high tumour-to-blood ratio already at 2 h (8.2 ± 1.9), which increased to 11.0 ± 0.5 at 4 h after injection. Significantly (p < 0.05) higher tumour-to-liver and higher tumour-to-bone ratios at 2 h in comparison with 4 h after injection were observed. Thus, [99mTc]Tc-AC12-GGGC could be a promising candidate for further development.

Clinical significance of B7-H3 and HER2 co-expression and therapeutic value of combination treatment in gastric cancer

BACKGROUND

Gastric cancer (GC) is a digestive system malignancy. Trastuzumab (a HER2-targeted monoclonal antibody) is an important targeted drug for GC. However, the drug resistance limits its clinical efficacy. B7-H3 was suggested to be a promising target for cancer immunotherapy. This study aimed to investigate the clinical significance of B7-H3 and HER2 co-expression and the therapeutic value of combination treatment in GC.

METHODS

We examined the expression of B7-H3 and HER2 in 268 GC patients by immunohistochemistry. Pearson test was used to analyze the correlation between categorical variables. Overall survival was assessed by Kaplan-Meier analysis. All in vitro experiments using HER2-positive GC cells were treated with small interfering RNA targeting B7-H3/HER2 or B7-H3 blocking antibody 3E8/trastuzumab to verify the antitumor efficacy of the combination therapy. GC xenograft mouse models were established to evaluate the in vivo anti-tumor effect of combined therapy.

RESULTS

There was a significant correlation between B7-H3 and HER2 expression in GC tissues. High co-expression of B7-H3 and HER2 was associated with poor prognosis (P = 0.007) and could be an independent risk factor for survival. In addition, knockdown or targeted therapies of B7-H3/HER2 significantly suppressed cell proliferation, migration, invasion and adhesion in vitro. Trastuzumab combined with 3E8 was significantly effective at reducing mice tumor growth than monotherapy.

CONCLUSION

High co-expression of B7-H3 and HER2 indicates a poor prognosis, and combination therapy targeting B7-H3 and HER2 could be an immunotherapeutic strategy for GC.

Signal pathways and precision therapy of small-cell lung cancer

Small-cell lung cancer (SCLC) encounters up 15% of all lung cancers, and is characterized by a high rate of proliferation, a tendency for early metastasis and generally poor prognosis. Most of the patients present with distant metastatic disease at the time of clinical diagnosis, and only one-third are eligible for potentially curative treatment. Recently, investigations into the genomic make-up of SCLC show extensive chromosomal rearrangements, high mutational burden and loss-of-function mutations of several tumor suppressor genes. Although the clinical development of new treatments for SCLC has been limited in recent years, a better understanding of oncogenic driver alterations has found potential novel targets that might be suitable for therapeutic approaches. Currently, there are six types of potential treatable signaling pathways in SCLC, including signaling pathways targeting the cell cycle and DNA repair, tumor development, cell metabolism, epigenetic regulation, tumor immunity and angiogenesis. At this point, however, there is still a lack of understanding of their role in SCLC tumor biology and the promotion of cancer growth. Importantly optimizing drug targets, improving drug pharmacology, and identifying potential biomarkers are the main focus and further efforts are required to recognize patients who benefit most from novel therapies in development. This review will focus on the current learning on the signaling pathways, the status of immunotherapy, and targeted therapy in SCLC.

Prognostic values of B7-H3, B7-H4, and HHLA2 expression in human pancreatic cancer tissues based on mIHC and spatial distribution analysis

BACKGROUND

Pancreatic cancer (PC) is one of the most malignant solid tumors and its 5-year survival rate remains poor. Although immunotherapy has achieved certain therapeutic efficacy in some clinical trials, such treatment still shows low responses and overall remission rate. Therefore, it is urgently necessary to dissect the tumor microenvironment and optimize the immunotherapeutic strategies against this malignancy.

METHODS

Using the multi-color immunohistochemistry assay, we investigated the expressions of B7-H3, B7-H4, HHLA2, CD8, and CD68 in 63 cases of PC tissues in a tissue microarray. Moreover, we analyzed immunolocalization features, clinical associations and prognostic values of these molecules.

RESULTS

The expressions of B7-H3, B7-H4, and HHLA2 could be detected in cytokeratin staining positive (CK+) cancer epithelial cells, CD68+tumor-associated macrophages (TAMs), and even other cells defined as CK-CD8-CD68-. Higher expression of B7-H3 in tumor cells could predict a better survival of the PC patients. A positive correlation was found between the expressions of B7-H3 and HHLA2 in tumor cells, while there was a negative correlation between the expressions of B7-H4 and HHLA2 in tumor cells. A positive correlation was found between the expressions of B7-H3 and B7-H4 or HHLA2 in CD68+TAMs, but not B7-H4 and HHLA2. Tumor-infiltrating CD8+T cells in combination with CD68+TAMs could serve as an important predictor for the postoperative prognosis of PC patients. Higher expression of B7-H3, or HHLA2 in CD68+TAMs could serve as an important predictor for poorer prognosis of PC patients. Patients with B7-H3lowB7-H4low, B7-H3lowHHLA2low, or B7-H4lowHHLA2low on CD68+TAMs could have a better postoperative prognosis compared with the other sub-populations in the combinational analysis.

CONCLUSIONS

Taken together, our study indicated variable expressions and prognostic values of B7-H3, B7-H4, and HHLA2, in human PC tissues, and demonstrated that these co-stimulator molecules expressed by CD68+TAMs could be used as important bio-markers for the prognostic prediction of PC patients. Moreover, these results supported that the evaluation of these markers could be used as essential candidate targets for immunotherapy against PC.

ALYREF associated with immune infiltration is a prognostic biomarker in hepatocellular carcinoma

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ALYREF is a potential prognostic marker for hepatocellular carcinoma.

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ALYREF affects the biological function of hepatocellular carcinoma cells.

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ALYREF is associated with immune infiltration in hepatocellular carcinoma.

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The model constructed based on ALYREF-related immune genes provides a reference for the evaluation of immunotherapy.

Background

Although ALYREF has been demonstrated to have a role in a number of malignancies, its role in hepatocellular carcinoma (HCC) has received little attention. Our objective was to research at the prognostic value, biological role and relevance of ALYREF to the immune system in HCC.

Methods

The expression of ALYREF and its relationship with clinical parameters of HCC patients were analyzed by liver cancer cohort (LIHC) of The Cancer Genome Atlas. The expression and prognosis were verified by immunohistochemistry experiments. Gene transfection, CCK-8, scratch healing, transwell invasion and flow cytometry were used to assess the molecular function of ALYREF in vitro. The TIMER and TISIDB online data portals were used to assess the relevance of ALYREF to immunization. Stepwise regression analysis of ALYREF-related immune genes in the LIHC training set was used to construct a prognostic risk prediction model. Also, construct a nomogram to predict patient survival. The testing set for internal verification.

Results

Knockdown of ALYREF changed the biological phenotypes of HCC cells, such as proliferation, apoptosis, and invasion. In addition, the expression of ALYREF in HCC affected the level of immune cell infiltration and correlated with the overall survival time of patients. The constructed immune prognostic model allows for a valid assessment of patients.

Conclusion

ALYREF is increased in HCC, has an impact on cellular function and the immune system, and might be used as a prognostic marker.

A Novel Anti-B7-H3 × Anti-CD3 Bispecific Antibody with Potent Antitumor Activity

B7-H3 plays an important role in tumor apoptosis, proliferation, adhesion, angiogenesis, invasion, migration, and evasion of immune surveillance. It is overexpressed in various human solid tumor tissues. In patients, B7-H3 overexpression correlates with advanced stages, poor clinical outcomes, and resistance to therapy. The roles of B7-H3 in tumor progression make it a potential candidate for targeted therapy. Here, we generated a mouse anti-human B7-H3 antibody and demonstrated its binding activity via Tongji University Suzhou Instituteprotein-based and cell-based assays. We then developed a novel format anti-B7-H3 × anti-CD3 bispecific antibody based on the antibody-binding fragment of the anti-B7-H3 antibody and single-chain variable fragment structure of anti-CD3 antibody (OKT3) and demonstrated that this bispecific antibody mediated potent cytotoxic activities against various B7-H3-positive tumor cell lines in vitro by improving T cell activation and proliferation. This bispecific antibody also demonstrated potent antitumor activity in humanized mice xenograft models. These results revealed that the novel anti-B7-H3 × anti-CD3 bispecific antibody has the potential to be employed in treatment of B7-H3-positive solid tumors.

Elucidating Spatially-Resolved Changes in Host Signaling During Plasmodium Liver-Stage Infection

Upon transmission to the human host, Plasmodium sporozoites exit the skin, are taken up by the blood stream, and then travel to the liver where they infect and significantly modify a single hepatocyte. Low infection rates within the liver have made proteomic studies of infected hepatocytes challenging, particularly in vivo, and existing studies have been largely unable to consider how protein and phosphoprotein differences are altered at different spatial locations within the heterogeneous liver. Using digital spatial profiling, we characterized changes in host signaling during Plasmodium yoelii infection in vivo without disrupting the liver tissue. Moreover, we measured alterations in protein expression around infected hepatocytes and identified a subset of CD163⁺ Kupffer cells that migrate towards infected cells during infection. These data offer the first insight into the heterogeneous microenvironment that surrounds the infected hepatocyte and provide insights into how the parasite may alter its milieu to influence its survival and modulate immunity.

Immune suppressive checkpoint interactions in the tumour microenvironment of primary liver cancers

Liver cancer is one of the most prevalent cancers, and the third most common cause of cancer-related mortality worldwide. The therapeutic options for the main types of primary liver cancer-hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA)-are very limited. HCC and CCA are immunogenic cancers, but effective immune-mediated tumour control is prevented by their immunosuppressive tumour microenvironment. Despite the critical involvement of key co-inhibitory immune checkpoint interactions in immunosuppression in liver cancer, only a minority of patients with HCC respond to monotherapy using approved checkpoint inhibitor antibodies. To develop effective (combinatorial) therapeutic immune checkpoint strategies for liver cancer, in-depth knowledge of the different mechanisms that contribute to intratumoral immunosuppression is needed. Here, we review the co-inhibitory pathways that are known to suppress intratumoral T cells in HCC and CCA. We provide a detailed description of insights from preclinical studies in cellular crosstalk within the tumour microenvironment that results in interactions between co-inhibitory receptors on different T-cell subsets and their ligands on other cell types, including tumour cells. We suggest alternative immune checkpoints as promising targets, and draw attention to the possibility of combined targeting of co-inhibitory and co-stimulatory pathways to abrogate immunosuppression.

Identification and Validation of an 6-Metabolism-Related Gene Signature and Its Correlation With Immune Checkpoint in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a common malignant tumor with relatively high malignancy and rapid disease progression. Metabolism-related genes (MRGs) are involved in the pathogenesis of HCC. This study explored potential key MRGs and their effect on T-cell immune function in the tumor immune microenvironment to provide new insight for the treatment of HCC. Of 456 differentially expressed MRGs identified from TCGA database, 21 were screened by MCODE and cytoHubba algorithms. From the key module, GAD1, SPP1, WFS1, GOT2, EHHADH, and APOA1 were selected for validation. The six MRGs were closely correlated with survival outcomes and clinicopathological characteristics in HCC. Receiver operating characteristics analysis and Kaplan-Meier plots showed that these genes had good prognostic value for HCC. Gene set enrichment analysis of the six MRGs indicated that they were associated with HCC development. TIMER and GEPIA databases revealed that WFS1 was significantly positively correlated and EHHADH was negatively correlated with tumor immune cell infiltration and immune checkpoint expression. Finally, quantificational real-time polymerase chain reaction (qRT-PCR) confirmed the expression of WFS1 and EHHADH mRNA in our own patients’ cohort samples and four HCC cell lines. Collectively, the present study identified six potential MRG biomarkers associated with the prognosis and tumor immune infiltration of HCC, thus providing new insight into the pathogenesis and treatment of HCC.

The role of B7-H3 in tumors and its potential in clinical application

B7-H3 (CD276 molecule) is an immune checkpoint from the B7 family of molecules that acts more as a co-inhibitory molecule to promote tumor progression. It is abnormally expressed on tumor cells and can be induced to express on antigen-presenting cells (APCs) including dendritic cells (DCs) and macrophages. In the tumor microenvironment (TME), B7-H3 promotes tumor progression by impairing T cell response, promoting the polarization of tumor-associated macrophages (TAMs) to M2, inhibiting the function of DCs, and promoting the migration and invasion of cancer-associated fibroblasts (CAFs). In addition, through non-immunological functions, B7-H3 promotes tumor cell proliferation, invasion, metastasis, resistance, angiogenesis, and metabolism, or in the form of exosomes to promote tumor progression. In this process, microRNAs can regulate the expression of B7-H3. B7-H3 may serve as a potential biomarker for tumor diagnosis and a marker of poor prognosis. Immunotherapy targeting B7-H3 and the combination of B7-H3 and other immune checkpoints have shown certain efficacy. In this review, we summarized the basic characteristics of B7-H3 and its mechanism to promote tumor progression by inducing immunosuppression and non-immunological functions, as well as the potential clinical applications of B7-H3 and immunotherapy based on B7-H3.

Expression characteristic of 4Ig B7-H3 and 2Ig B7-H3 in acute myeloid leukemia

4IgB7-H3 (4Ig) and 2IgB7-H3 (2Ig) expression characteristics in acute myeloid leukemia (AML) remain unknown. This study investigated mRNA and membrane protein expression of two B7-H3 isoforms in AML cell lines and de novo patients by using RT-PCR and flow cytometry, and analyzed the B7-H3 promoter methylation state by utilizing RQ-MSP. 4Ig was the dominant isoform. 2Ig mRNA expression rate and abundance were elevated in AML in comparison with controls (P = 0.000 and 0.000), while no significant difference in 4Ig (P = 0.802, P = 0.398). Membrane protein levels of B7-H3 isoforms in AML was higher than controls, detected by total B7-H3 expression rate (P = 0.002), total B7-H3 mean fluorescence intensity (MFI) ratio of blast cells and lymphocytes (MFI ratio) (P = 0.000), and 4Ig B7-H3 MFI ratio (P = 0.005). Compared with 2Ig^low group, 2Ig^high patients had older age, lower NPM1 mutation, higher FLT3-ITD mutation, and declining complete remission (CR) rates (P = 0.026, 0.012, 0.047, and 0.028). In B7-H3^high group, there was a trend toward older age, M4 and M5, worse karyotype, and lower CR rates, although with no marked difference (P > 0.05). The overall survival (OS) of 2Ig^high and B7-H3^high groups were shorter than that of 2Ig^low and B7-H3^low groups in the whole and non-M3 AML cohorts (P = 0.006 and 0.046; P = 0.003 and 0.032). Besides, an unmethylated B7-H3 promoter was identified. In conclusion, 2Ig mRNA and total B7-H3 membrane protein tended to have potential diagnostic value for AML. Specifically, high 2Ig mRNA and total B7-H3 membrane protein expression indicate worse OS. 4Ig and 2Ig expression are methylation-independent.

B7 score and T cell infiltration stratify immune status in prostate cancer

BACKGROUND

Although immune checkpoint inhibitors (ICIs), especially programmed cell death protein 1 (PD-1)/programmed death ligand 1 (PD-L1) axis blockers, exhibit prominent antitumor effects against numerous malignancies, their benefit for patients with prostate cancer (PCa) has been somewhat marginal. This study aimed to assess the feasibility of B7-H3 or HHLA2 as alternative immunotherapeutic targets in PCa.

METHODS

Immunohistochemistry was performed to evaluate the expression pattern of PD-L1, B7-H3 and HHLA2 and the infiltration of CD8⁺ and Foxp3⁺ lymphocytes in 239 PCa tissues from two independent cohorts. The correlations between B7-H3 and HHLA2 and clinicopathological features, including the presence of CD8⁺ and Foxp3⁺ tumor-infiltrating lymphocytes (TILs), were explored.

RESULTS

HHLA2 expression was much higher than PD-L1 expression but lower than B7-H3 expression in PCa tissues. High expression of both B7-H3 and HHLA2 was significantly associated with higher Gleason score and tumor stage, lymph node metastasis and dismal overall survival (OS) and cancer-specific survival (CSS). Moreover, a high B7 score, defined as high B7-H3 expression and/or high HHLA2 expression, was an independent prognostic predictor for PCa. Of note, a high B7 score was negatively correlated with CD8⁺ TILs. Importantly, a new immune classification, based on the B7 score and CD8⁺ TILs, successfully stratified OS and CSS in PCa.

CONCLUSIONS

Both B7-H3 and HHLA2 have a critical impact on the immunosuppressive microenvironment, and the B7 score could be used as an independent prognostic factor for PCa. The B7 score combined with CD8⁺ TILs could be used as a new immune classification to stratify the risk of death, especially cancer-related death, for patients with PCa. These findings may provide insights that could improve response to immune-related comprehensive therapy for PCa in the future.

CD276 is an important player in macrophage recruitment into the tumor and an upstream regulator for PAI-1

More than 70% of colorectal, prostate, ovarian, pancreatic and breast cancer specimens show expression of CD276 (B7–H3), a potential immune checkpoint family member. Several studies have shown that high CD276 expression in cancer cells correlates with a poor clinical prognosis. This has been associated with the presence of lower tumor infiltrating leukocytes. Among those, tumor-associated macrophages can comprise up to 50% of the tumor mass and are thought to support tumor growth through various mechanisms. However, a lack of information on CD276 function and interaction partner(s) impedes rigorous evaluation of CD276 as a therapeutic target in oncology. Therefore, we aimed to understand the relevance of CD276 in tumor-macrophage interaction by employing a 3D spheroid coculture system with human cells. Our data show a role for tumor-expressed CD276 on the macrophage recruitment into the tumor spheroid, and also in regulation of the extracellular matrix modulator PAI-1. Furthermore, our experiments focusing on macrophage-expressed CD276 suggest that the antibody-dependent CD276 engagement triggers predominantly inhibitory signaling networks in human macrophages.

Nanomedicine Approach to Immunotherapy of Hepatocellular Carcinoma

In recent years, the growing studies focused on the immunotherapy of hepatocellular carcinoma and proved the preclinical and clinical promises of host antitumor immune response. However, there were still various obstacles in meeting satisfactory clinic need, such as low response rate, primary resistance and secondary resistance to immunotherapy. Tackling these barriers required a deeper understanding of immune underpinnings and a broader understanding of advanced technology. This review described immune microenvironment of liver and HCC which naturally decided the complexity of immunotherapy, and summarized recent immunotherapy focusing on different points. The ever-growing clues indicated that the instant killing of tumor cell and the subsequent relive of immunosuppressive microenvironment were both indis- pensables. The nanotechnology applied in immunotherapy and the combination with intervention technology was also discussed.

B7-H3 targeted antibody-based immunotherapy of malignant diseases

Introduction: Recent advances in immuno-oncology and bioengineering have rekindled the interest in monoclonal antibody (mAb)-based immunotherapies for malignancies. Crucial for their success is the identification of tumor antigens (TAs) that can serve as targets. B7-H3, a member of the B7 ligand family, represents such a TA. Although its exact functions and receptor(s) remain unclear, B7-H3 has predominantly a pro-tumorigenic effect mainly by suppressing the anti-tumor functions of T-cells.Areas covered: Initially we present a historical perspective on TA-specific antibodies for diagnosis and treatment of malignancies. Following a description of the TA requirements to be an attractive antibody-based immunotherapy target, we show that B7-H3 fulfills these criteria. We discuss its structure and functions. In a review and pooled analysis, we describe the limited B7-H3 expression in normal tissues and estimate B7-H3 expression frequency in tumors, tumor-associated vasculature and cancer initiating cells (CICs). Lastly, we discuss the association of B7-H3 expression in tumors with poor prognosis.Expert opinion: B7-H3 is an attractive target for mAb-based cancer immunotherapy. B7-H3-targeting strategies are expected to be highly effective and - importantly - safe. To fully exploit the diagnostic and therapeutic potential of B7-H3, its expression in pre-malignant lesions, serum, metastases, and CICs requires further investigation.

Expression, regulation and clinical significance of B7-H3 on neutrophils in human gastric cancer

Neutrophils are conspicuous components of gastric cancer (GC) tumors, increasing with tumor progression and poor patient survival. However, the phenotype, regulation and clinical relevance of neutrophils in human GC are presently unknown. Most intratumoral neutrophils showed an activated CD54⁺ phenotype and expressed high level B7-H3. Tumor tissue culture supernatants from GC patients induced the expression of CD54 and B7-H3 on neutrophils in time-dependent and dose-dependent manners. Locally enriched CD54⁺ neutrophils and B7-H3⁺ 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-H3 on neutrophils in both time-dependent and dose-dependent manners. Furthermore, GC tumor-derived GM-CSF activated neutrophils and induced neutrophil B7-H3 expression via JAK-STAT3 signaling pathway activation. Finally, intratumoral B7-H3⁺ neutrophils increased with tumor progression and independently predicted reduced overall survival. Collectively, these results suggest B7-H3⁺ neutrophils to be potential biomarkers in GC.

Immuno-profiling and cellular spatial analysis using five immune oncology multiplex immunofluorescence panels for paraffin tumor tissue

Multiplex immunofluorescence (mIF) has arisen as an important tool for immuno-profiling tumor tissues. We updated our manual protocol into an automated protocol that allows the use of up to seven markers in five mIF panels to apply to formalin-fixed paraffin-embedded tumor tissues. Using a tyramide signal amplification system, we optimized five mIF panels that included cytokeratin to characterize malignant cells (MCs), immune checkpoint markers (i.e., PD-L1, B7-H3, B7-H4, IDO-1, VISTA, LAG3, ICOS, TIM3, and OX40), tumor-infiltrating lymphocytic markers (i.e., CD3, CD8, CD45RO, granzyme B, PD-1, and FOXP3), and markers to characterize myeloid-derived suppressor cells (i.e., CD68, CD66b, CD14, CD33, Arg-1, and CD11b). To determine analytical reproducibility and the impact of those panels for immuno-profiling tumor tissues, we performed an exploratory analysis in a set of non–small cell lung cancer (NSCLC) samples. The slides were scanned, and the different cell phenotypes were quantified by simultaneous co-localizations with the markers using image analysis software. Comparison between the time points of staining showed high analytical reproducibility. The analysis of NSCLC cases showed an immunosuppressive microenvironment with PD-L1/PD-1 expression as a predominant axis. Interestingly, high density of MCs expressing B7-H4 was correlated with recurrence. Unexpectedly, MCs expressing OX40 were also detected, and those cells were a closer distance to CD3+T-cells than were MCs expressing other immune checkpoints. Two different cellular patterns of spatial distribution were determined according the CD3 distribution, and the predominant pattern was related with active immunosuppressive interaction with MCs. Our study shows that these five mIF panels can identify multiple targets in a single cell with high reproducibility. The study of different cell populations and their spatial relationship can open new ideas for therapeutic approaches.

The Expression of Three Negative Co-Stimulatory B7 Family Molecules in Small Cell Lung Cancer and Their Effect on Prognosis

Background

In recent years, immune checkpoint inhibitors have shown significant effects in a variety of solid tumors. However, due to the low incidence of small cell lung cancer (SCLC) and its unclear mechanism, immune checkpoints in SCLC have not been fully studied.

Methods

We evaluated the expression of PD-L1, B7-H3, and B7-H4 in 115 SCLC tissue specimens using immunohistochemistry. The clinical data of patients with SCLC were retrospectively reviewed to investigate three negative co-stimulatory B7 family molecules’ ability to affect the prognosis of SCLC.

Results

Among the SCLC patients with complete follow-up data (n = 107), sixty-nine (64.49%) expressed moderate to high B7-H3 levels, which correlated positively with tumor sizes (P < 0.001). Eighty (74.77%) patients expressed moderate to high B7-H4 levels, which correlated positively with metastases (P = 0.049). The positive expression of B7-H3 and B7-H4 correlated significantly with shortened overall survival (OS) (B7-H3, P = 0.006; B7-H4, P = 0.019). PD-L1 was positively expressed only in 13.08% of cancer tissues, and there was no significant correlation with prognosis. The Cox proportional hazards regression showed that B7-H3 was an independent prognostic indicator of OS (P = 0.028; HR = 2.125 [95% CI = 0.985-4.462]).

Conclusions

Our results suggest that B7-H3 has a negative predictive effect on SCLC. This outcome provides a theoretical basis for the subsequent research on immune checkpoint inhibitors targeting B7-H3.

The Role of CD276 in Cancers

Objective

Aberrant expression of the immune checkpoint molecule, CD276, also known as B7-H3, is associated with tumorigenesis. In this review, we aim to comprehensively describe the role of CD276 in malignancies and its potential therapeutic effect.

Data Sources

Database including PubMed, EMbase, Cochrane Library, CNKI, and Clinical Trails.gov were searched for eligible studies and reviews. Study selection: Original studies and review articles on the topic of CD276 in tumors were retrieved.

Results

CD276 is an immune checkpoint molecule in the epithelial mesenchymal transition (EMT) pathway. In this review, we evaluated the available evidence on the expression and regulation of CD276. We also assessed the role of CD276 within the immune micro-environment, effect on tumor progression, and the potential therapeutic effect of CD276 targeted therapy for malignancies.

Conclusion

CD276 plays an essential role in cell proliferation, invasion, and migration in malignancies. Results from most recent studies indicate CD276 could be a promising therapeutic target for malignant tumors.

B7-H3 and digestive system cancers

Digestive system cancers (DSC) are the most common cancers worldwide and often associated with poor prognosis because of their characteristics of invasive and metastatic. Thus, it is particularly necessary to find novel molecular targets for early diagnosis, as well as targeted treatment of DSC. B7-H3, which was previously referred to as a modulatory ligand that regulate T-cell-mediated immune reaction, is a B7-family member of co-stimulatory biomolecules, and in recent years it was found that its concentration was remarkably up modulated in serum, as well as tissues of DSC patients. Numerous studies have documented that B7-H3 has a vital function in the DSC. Herein, we summarize the current literature on diagnosis and prognosis potential of B7-H3 in DSC including those of the esophagus, gastric, liver, pancreas, and colon.

CD276 Promotes Vasculogenic Mimicry Formation in Hepatocellular Carcinoma via the PI3K/AKT/MMPs Pathway

Purpose

CD276 protein expression and vasculogenic mimicry (VM) formation are associated with the poor prognosis of hepatocellular carcinoma (HCC) patients. Although both the effects of CD276 and VM formation involve the activation of matrix metalloproteinases, and their relationship has not yet been explored. The following study investigated the effect of CD276 expression on VM formation and the potential mechanisms.

Materials and Methods

CD276 expression and VM were examined in commercial tissue microarrays by immunohistochemistry and CD31/PAS double staining. Tumor cell proliferation, invasion, migration and, tube formation were detected in vitro after transfecting HCC cell lines with an shRNA lentiviral vector against CD276. The expression of MMP14, MMP2, VE-cadherin, E-cadherin, and vimentin and MMPs activation was detected by Western blot, immunofluorescence and gelatin zymography assay. In addition, an orthotopic xenograft model of HCC cells was established in vivo, after which VM was detected, along with its marker molecules.

Results

CD276 expression was associated with VM and poor prognosis in HCC patients. RNA interference of CD276 reduced tumor cell proliferation, invasion, migration, and VM formation in vitro and in vivo. Furthermore, CD276 knockdown up-regulated the expression of E-cadherin but inhibited the phosphorylation of AKT, the expression of MMP14, MMP2, VE-cadherin, vimentin and the activation of MMP2 and MMP9 in HCC cell lines.

Conclusion

CD276 may promote VM formation by activating the PI3K/AKT/MMPs pathway and inducing the EMT process in HCC. CD276 may serve as a promising candidate for the anti-VM treatment of HCC.

B7-H3 immune checkpoint expression is a poor prognostic factor in colorectal carcinoma

Although PD-1/PD-L1 immunotherapy has been used successfully in treating many cancers, metastatic colorectal cancer (CRC) patients are not as responsive. B7-H3 is a promising target for immunotherapy and we found it to have the highest expression among B7-CD28 family members in CRC. Thus, the aim of the present study was to investigate B7-H3 expression in a large CRC cohort. B7-H3, B7-H4, and PD-L1 protein levels and differential lymphocyte infiltration were evaluated in tissue microarrays from 805 primary tumors and matched metastases. The relationships between immune markers, patient characteristics, and survival outcomes were determined. B7-H3 (50.9%) was detected in more primary tumors than B7-H4 (29.1%) or PD-L1 (29.2%), and elevated B7-H3 expression was associated with advanced overall stage. Co-expression of B7-H3 only with B7-H4 or PD-L1 was infrequent in primary tumors (6.3%, 5.7%, respectively). Moreover, B7-H3 in primary tumors was positively correlated with their respective expression at metastatic sites (ρ = 0.631; p < 0.001). No significant relationships between B7-H4 and PD-L1 and survival were observed; however, B7-H3 overexpression in primary tumors was significantly related to decreased disease-free survival. A positive relationship between B7-H3 expression and high density CD45RO T cell was observed in primary tumors, whereas B7-H4 and PD-L1 overexpression were related to CD3 T-cell infiltration. In conclusion, compared with B7-H4 and PD-L1, B7-H3 expression exhibited a higher prevalence and was significantly related to aggressiveness, worse prognosis and CD45RO T-cell infiltration in primary tumors. Further exploration of this potential target of immunotherapy in CRC patients is warranted.

Varied functions of immune checkpoints during cancer metastasis

Immune checkpoints comprise diverse receptors and ligands including costimulatory and inhibitory molecules, which play monumental roles in regulating the immune system. Immune checkpoints retain key potentials in maintaining the immune system homeostasis and hindering the malignancy development and autoimmunity. The expression of inhibitory immune checkpoints delineates an increase in a plethora of metastatic tumors and the inhibition of these immune checkpoints can be followed by promising results. On the other hand, the stimulation of costimulatory immune checkpoints can restrain the metastasis originating from diverse tumors. From the review above, key findings emerged regarding potential functions of inhibitory and costimulatory immune checkpoints targeting the metastatic cascade and point towards novel potential Achilles’ heels of cancer that might be exploited therapeutically in the future.

Correlation Patterns Among B7 Family Ligands and Tryptophan Degrading Enzymes in Hepatocellular Carcinoma

Mechanisms of dysfunctional T cell immunity in Hepatocellular Carcinoma (HCC) need to be well defined. B7 family molecules provide both co-stimulatory and co-inhibitory signals to T cells while tryptophan degrading enzymes like Indoleamine 2,3 dioxygenase (IDO) and Tryptophan 2,3 Dioxygenase (TDO) mediate tumor immune tolerance. It is necessary to identify their in situ correlative expression, which informs targets for combined immunotherapy approaches. We investigated B7 family molecules, IDO, TDO and immune responsive effectors in the tumor tissues of patients with HCC (n = 28) using a pathway-focused quantitative nanoscale chip real-time PCR. Four best correlative expressions, namely (1) B7-1 & PD-L2, (2) B7-H2 & B7-H3, (3) B7-2 & PD-L1, (4) PD-L1 & PD-L2, were identified among B7 family ligands, albeit they express at different levels. Although TDO expression is higher than IDO, PD-L1 correlates only with IDO but not TDO. Immune effector (Granzyme B) and suppressive (PD-1 and TGF-β) genes correlate with IDO and B7-1, B7-H5, PD-L2. Identification of the in situ correlation of PD-L1, PD-L2 and IDO suggest their cumulative immuno suppressive role in HCC. The distinct correlations among B7-1, B7-2, B7-H2, and B7-H3, correlation of PD-1 with non-cognate ligands such as B7-1 and B7-H5, and correlation of tumor lytic enzyme Granzyme B with IDO and PD-L2 suggest that HCC microenvironment is complexly orchestrated with both stimulatory and inhibitory molecules which together neutralize and blunt anti-HCC immunity. Functional assays demonstrate that both PDL-1 and IDO synergistically inhibit T cell responses. Altogether, the present data suggest the usage of combined immune checkpoint blocking strategies targeting co-inhibitory B7 molecules and IDO for HCC management.

B7-H3 Immune Checkpoint Protein in Human Cancer

B7-H3 belongs to the B7 family of immune checkpoint proteins, which are important regulators of the adaptive immune response and emerging key players in human cancer. B7-H3 is a transmembrane protein expressed on the surface of tumor cells, antigen presenting cells, natural killer cells, tumor endothelial cells, but can also be present in intra- and extracellular vesicles. Additionally, B7-H3 may be present as a circulating soluble isoform in serum and other body fluids. B7-H3 is overexpressed in a variety of tumor types, in correlation with poor prognosis. B7-H3 is a promising new immunotherapy target for anti-cancer immune response, as well as a potential biomarker. Besides its immunoregulatory role, B7-H3 has intrinsic pro-tumorigenic activities related to enhanced cell proliferation, migration, invasion, angiogenesis, metastatic capacity and anti-cancer drug resistance. B7-H3 has also been found to regulate key metabolic enzymes, promoting the high glycolytic capacity of cancer cells. B7-H3 receptors are still not identified, and little is known about the molecular mechanisms underlying B7-H3 functions. Here, we review the current knowledge on the involvement of B7-H3 in human cancer.

News on immune checkpoint inhibitors as immunotherapy strategies in adult and pediatric solid tumors

Immune checkpoint inhibitors (ICIs) have shown unprecedented benefits in various adult cancers, and this success has prompted the exploration of ICI therapy even in childhood malignances. Although the use of ICIs as individual agents has achieved disappointing response rates, combinational therapies are likely to promise better results. However, only a subset of patients experienced prolonged clinical effects, thus suggesting the need to identify robust bio-markers that predict individual clinical response or resistance to ICI therapy as the main challenge. In this review, we focus on how the use of ICIs in adult cancers can be translated into pediatric malignances. We discuss the physiological mechanism of action of each IC, including PD-1, PD-L1 and CTLA-4 and the new emerging ones, LAG-3, TIM-3, TIGIT, B7-H3, BTLA and IDO-1, and evaluate their prognostic value in both adult and childhood tumors. Furthermore, we offer an overview of preclinical models and clinical trials currently under investigation to improve the effectiveness of cancer immunotherapies in these patients. Finally, we outline the main predictive factors that influence the efficacy of ICIs, in order to lay the basis for the development of a pan-cancer immunogenomic model, able to direct young patients towards more specific immunotherapy.

Identification of immunological subtypes of hepatocellular carcinoma with expression profiling of immune-modulating genes

Recent studies demonstrate that immune checkpoint inhibitor (ICI) therapy has achieved success in many types of advanced cancers including advanced hepatocellular carcinoma (HCC). However, ICI therapy is beneficial in only some HCC patients, suggesting that immune-responses are highly variable in HCCs. Therefore, understanding the immune status in HCC microenvironment will facilitate ICI immunotherapy and guide patient selection for the therapy. In this study, we first analyzed the expression profile of immune-modulating genes and their relationship with survival of HCC patients using the data downloaded from The Cancer Genome Atlas - Liver Hepatocellular Carcinoma (TCGA-LIHC) database, and found that the higher expressions of CD276 (B7-H3) and CD47 were significantly associated with poor survival. Then we identified 4 immune subtypes of HCCs with different survivals by using the combination expression of B7-H3 (or CD47) and CD8. Patients with B7-H3^low/CD8^high or CD47^low/CD8^high have the best survival while ones with B7-H3^high/CD8^low or CD47^high/CD8^low have the worst survival. The 4 immune subtypes were validated in another 72 HCC patients obtained from South China. In conclusion, our findings suggest that HCC patient prognosis is associated with immunophenotypes by T cell infiltration (CD8 expression) and the expression of the adaptive immune resistance gene (B7-H3 or CD47), and this immune classification system will facilitate HCC patient selection for ICI immunotherapy.

Effects of B7-H3 expression on tumour-infiltrating immune cells and clinicopathological characteristics in non-small-cell lung cancer

PURPOSE

B7-H3 has emerged as a promising target for cancer immunotherapy. We assessed the role of B7-H3 expression in tumour-infiltrating immune cells in non-small-cell lung cancer (NSCLC).

METHODS

Tumour-infiltrating immune cell characterisation was performed by flow cytometry in a prospective cohort, whereas the relationship between B7-H3 expression and clinicopathological features was explored in a retrospective cohort.

RESULTS

B7-H3 expression was detected in tumour/epithelial cells and immune cells, including macrophages, monocytes, dendritic cells (DCs) and myeloid-derived suppressor cells. B7-H3 was expressed at higher levels in cells within the tumour than in cells within non-neoplastic tissues. B7-H3 expression score in tumour cells positively correlated with the amount of CD45⁺ immune cells (rho = 0.305, P = 0.010), CD8⁺ T-cells (rho = 0.330, P = 0.005), and the percentage of CD8⁺/CD3⁺ T-cells (rho = 0.403, P < 0.001). Patients with high tumoural B7-H3 expression showed increased numbers of immune cells (P = 0.002), CD8⁺ T-cells (P = 0.011), natural killer cells (P = 0.073) and plasmacytoid DCs (P = 0.015). Tumoural B7-H3 expression was higher in males, smokers, squamous cell carcinomas, tumours with wild-type EGFR, poor differentiation, larger size and nodal metastasis (P < 0.05, all). Tumoural B7-H3 expression was associated with PD-L1 expression (P = 0.001), shorter 5-year overall survival (P = 0.012) and poor survival after anti-PD-1 blockade (P = 0.026).

CONCLUSIONS

Tumoural B7-H3 overexpression was associated with increased tumour-infiltrating cytotoxic lymphocytes and poor prognosis in NSCLC. Thus, B7-H3 is a promising prognostic biomarker and immunotherapeutic target in NSCLC.

Targets and Antibody Formats for Immunotherapy of Neuroblastoma

Neuroblastoma (NB) is a malignant embryonal tumor of the sympathetic nervous system that is most commonly diagnosed in the abdomen, often presenting with signs and symptoms of metastatic spread. Three decades ago, high-risk NB metastatic to bone and bone marrow in children was not curable. Today, with multimodality treatment, 50% of these patients will survive, but most suffer from debilitating treatment-related complications. Novel targeted therapies to improve cure rates while minimizing toxicities are urgently needed. Recent molecular discoveries in oncology have spawned the development of an impressive array of targeted therapies for adult cancers, yet the paucity of recurrent somatic mutations or activated oncogenes in pediatric cancers poses a major challenge to the evolving paradigm of personalized medicine. Although low tumor mutational burden is a major hurdle for immune checkpoint inhibitors, an immature or impaired immune system and inhibitory tumor microenvironment can further complicate the prospects for successful immunotherapy. In this regard, despite the poor immunogenic properties of NB, the success of antibody-based immunotherapy and radioimmunotherapy directed at single targets (eg, GD2 and B7-H3) is both encouraging and surprising, given that most solid tumor antibodies that use Fc-dependent mechanisms or radioimmunotargeting have largely failed. Here, we summarize the current information on the immunologic properties of this tumor, its potential immunotherapeutic targets, and novel antibody-based strategies on the horizon.

Overexpression of B7-H3 in α-SMA-Positive Fibroblasts Is Associated With Cancer Progression and Survival in Gastric Adenocarcinomas

Background: B7-H3 promotes tumor immune escape and is highly expressed in tumor tissues. Stromal cells in tumors, including fibroblasts, play an important role in this process; however, the role of B7-H3 in tumor fibroblasts has not been fully clarified.

Methods: We examined B7-H3, CD31, and alpha-smooth muscle actin (α-SMA) protein expression in 268 gastric adenocarcinomas (GACs) by immunohistochemistry. The coexpression of B7-H3 with CD31 or α-SMA was examined using immunofluorescence double staining. Cytokine expression from fibroblasts treated with B7-H3 small interfering RNA (siRNA) was analyzed by a Quantitative reverse transcription-polymerase chain reaction (qPCR) and Enzyme-linked immunosorbent assay (ELISA). The transwell tests were conducted to assess the migration and invasion ability of fibroblasts. The overall survival was analyzed by a Kaplan-Meier analysis. Associations between categorical variables were assessed using the Pearson's Chi-square test or Fisher's exact test.

Results: GAC patients with B7-H3 expression showed significantly poorer survival (P = 0.012). The overall survival of the group with high B7-H3 expression was significantly worse than the group with low B7-H3 expression in both tumor cells and in stromal cells (P = 0.007 and P = 0.048, respectively). B7-H3 expression correlated with many clinicopathological data, including tumor stage, tumor depth, lymph node involvement, and survival. Immunofluorescence staining showed that B7-H3 was expressed in tumor cells and α-SMA-positive fibroblasts. Remarkably, high expression of α-SMA was associated with a poor prognosis (P = 0.007), and the prognoses of patients with high stromal expression of B7-H3 and α-SMA were significantly worse than that of other combination types (P = 0.001). Additionally, the absence of B7-H3 led to decreased secretion of cytokines, such as interleukin (IL)-6 and vascular endothelial growth factor (VEGF), as well as a decline in migration and invasion ability in cancer-associated fibroblasts (CAFs).

Conclusions: Patients with high B7-H3 expression either in tumor cells or in stromal cells had significantly poorer overall survival. Stromal B7-H3 expression was mostly detected in α-SMA-positive CAFs. GAC patients with both stromal B7-H3-high and α-SMA-high expression had significantly poorer overall survival, suggesting that stromal B7-H3 and α-SMA expression status can serve as an indicator of poor prognosis for GAC patients.

Immune Checkpoint Inhibitors: Basics and Challenges

Cancer is one of the most deadly diseases in the modern world. The last decade has witnessed dramatic advances in cancer treatment through immunotherapy. One extremely promising means to achieve anti-cancer immunity is to block the immune checkpoint pathways - mechanisms adopted by cancer cells to disguise themselves as regular components of the human body. Many review articles have described a variety of agents that are currently under extensive clinical evaluation. However, while checkpoint blockade is universally effective against a broad spectrum of cancer types and is mostly unrestricted by the mutation status of certain genes, only a minority of patients achieve a complete response. In this review, we summarize the basic principles of immune checkpoint inhibitors in both antibody and smallmolecule forms and also discuss potential mechanisms of resistance, which may shed light on further investigation to achieve higher clinical efficacy for these inhibitors.

A risk assessment model of acute liver allograft rejection by genetic polymorphism of CD276

Background

Liver transplantation is an effective therapy for end‐stage liver diseases and acute liver failure. After the operation, however, recipients may suffer grafts loss induced by alloimmune reaction, which is termed as acute allograft rejection. The interaction between costimulatory molecules, CD276, and its ligand, TREML2, promotes T cell‐mediated immune response, as well as acute or chronic allograft rejection. Our research aimed at correlating genetic polymorphisms of CD276/TREML2 with acute rejection, and evaluating its prognostic value of acute rejection after liver transplantation.

Methods

The study enrolled a total of 388 recipients. Among them, acute allograft rejection was observed in 54 cases. We performed single nucleotide polymorphism genotyping of CD276, including rs11072431, rs11574495, rs12593558, rs12594627, rs2127015, rs3816661 and rs7176654, and TREML2, including rs4714431, rs6915083, rs7754593, and rs9394767 from preoperative peripheral blood genome DNA.

Results

We found rs2127015 of CD276, rs6915083 and rs7754593 of TREML2, and HBV infection as well were associated with acute rejection. And, rs2127015 influences CD276 expression. Moreover, we established a risk assessment model, composited by statistically proved risk factors.

Conclusion

By integrating both clinical and genetic variables, liver transplant recipients can be categorized into different risk groups, and might benefit from individualized therapies.

Role of Tumor-Associated Macrophages in the Clinical Course of Pancreatic Neuroendocrine Tumors (PanNETs)

PURPOSE

This study evaluated the potential role of immune cells and molecules in the pathogenesis and clinical course of pancreatic neuroendocrine tumors (PanNET).

EXPERIMENTAL DESIGN

Surgically resected PanNETs (N = 104) were immunohistochemically analyzed for Ki67 index, mitotic rate, macrophage, CD4⁺ cells, and CD8⁺ T-cell infiltration, as well as HLA class I, PD-L1, and B7-H3 expression. Results were correlated with clinicopathologic characteristics as well as with disease-free (DFS) and disease-specific (DSS) survival.

RESULTS

The median age of the 57 WHO grade 1 and 47 WHO grade 2 patients was 55 years. High intratumoral CD8⁺ T-cell infiltration correlated with prolonged DFS (P = 0.05), especially when the number of tumor-associated macrophages (TAM) was low. In contrast, high peritumoral CD4⁺ cell and TAM infiltration was associated with a worse DFS and DSS. PD-L1 and B7-H3 were expressed in 53% and 78% PanNETs, respectively. HLA class I expression was defective in about 70% PanNETs. HLA-A expression correlated with favorable DSS in PD-L1-negative tumors (P = 0.02). TAM infiltration (P = 0.02), WHO grade (P = 0.04), T stage (P = 0.01), and lymph node positivity (P = 0.04) were independent predictors of DFS. TAM infiltration (P = 0.026) and T stage (P = 0.012) continued to be predictors of DFS in WHO grade 1 PanNET patients. TAM infiltration was the sole independent predictor of DSS for WHO grade 1 and 2 patients (P = 0.02). Therefore, this biomarker may contribute to identifying WHO grade 1 patients with poor prognosis.

CONCLUSIONS

TAM infiltration appears to be the most informative prognostic biomarker in PanNET. It may represent a useful immunotherapeutic target in patients with PanNET.

Genomic Characteristics of Invasive Mucinous Adenocarcinomas of the Lung and Potential Therapeutic Targets of B7-H3

Pulmonary invasive mucinous adenocarcinoma (IMA) is considered a variant of lung adenocarcinomas based on the current World Health Organization classification of lung tumors. However, the molecular mechanism driving IMA development and progression is not well understood. Thus, we surveyed the genomic characteristics of IMA in association with immune-checkpoint expression to investigate new potential therapeutic strategies. Tumor cells were collected from surgical specimens of primary IMA, and sequenced to survey 53 genes associated with lung cancer. The mutational profiles thus obtained were compared in silico to conventional adenocarcinomas and other histologic carcinomas, thereby establishing the genomic clustering of lung cancers. Immunostaining was also performed to compare expression of programmed death ligand 1 (PD-L1) and B7-H3 in IMA and conventional adenocarcinomas. Mutations in Kirsten rat sarcoma viral oncogene homolog (KRAS) were detected in 75% of IMAs, but in only 11.6% of conventional adenocarcinomas. On the other hand, the frequency of mutations in epidermal growth factor receptor (EGFR) and tumor protein p53 (TP53) genes was 5% and 10%, respectively, in the former, but 48.8% and 34.9%, respectively, in the latter. Clustering of all 78 lung cancers indicated that IMA is distinct from conventional adenocarcinoma or squamous cell carcinoma. Strikingly, expression of PD-L1 in ≥1% of cells was observed in only 6.1% of IMAs, but in 59.7% of conventional adenocarcinomas. Finally, 42.4% and 19.4% of IMAs and conventional adenocarcinomas, respectively, tested positive for B7-H3. Although currently classified as a variant of lung adenocarcinoma, it is also reasonable to consider IMA as fundamentally distinct, based on mutation profiles and genetic clustering as well as immune-checkpoint status. The immunohistochemistry data suggest that B7-H3 may be a new and promising therapeutic target for immune checkpoint therapy.

B7-H3 on circulating epithelial tumor cells correlates with the proliferation marker, Ki-67, and may be associated with the aggressiveness of tumors in breast cancer patients

Circulating epithelial tumor cells (CETCs) in peripheral blood are a prerequisite for the development of metastases. B7-H3 is an important immune checkpoint member of the B7 family and inhibits T-cell mediated antitumor immunity. Its expression is associated with a negative prognosis and a poor clinical outcome. Based on the clinical success of inhibitory immune checkpoint blockade, monoclonal antibodies (mAbs) against B7-H3 appear to be a promising therapeutic strategy. The proliferation biomarker, Ki-67, is used as a prognostic factor for breast cancer and reflects the proliferative potential of the tumor. In order to better understand the role of B7-H3 and Ki-67 in cancer development, in this study, we used a real-time biopsy for determining both biomarkers on CETCs in breast cancer patients. Blood from 50 patients suffering from breast cancer was analyzed for CETCs and the expression of B7-H3 and Ki-67 using the maintrac® method. B7-H3 expression on CETCs was found in 82% of the patients. The frequency of B7-H3- and Ki-67‑positive CETCs was significantly higher in patients who had received radiation therapy compared to patients who had not received irradiation. B7-H3‑positive CETCs seemed to be more aggressive as the percentage of B7-H3‑positive CETCs correlated with the percentage of cells positive for the proliferation marker, Ki-67 (r=0.72 P<0.001). A significant association between the Ki-67 and B7-H3 expression level on the CETCs and nodal status was observed. On the whole, the findings of this study indicate that breast cancer patients have detectable CETCs with a high frequency of B7-H3 expression regardless of the stage of the disease. B7-H3 seems to be an important factor in immune evasion and may thus be a promising target for anticancer therapies. Radiation may lead to an upregulation of B7-H3 expression on CETCs, which could be a possible mechanism of acquired radio-resistance.

Large-scale analysis reveals the specific clinical and immune features of B7-H3 in glioma

Background: B7-H3 is an immune checkpoint member that belongs to B7-CD28 families and plays a vital role in the inhibition of T-cell function. Importantly, B7-H3 is widely overexpressed on solid tumors, making it become an attractive target for cancer immunotherapy. To clarify the expression panel of B7-H3 in glioma, we explored the clinical and immune features of B7-H3 expression in a large-scale study. Methods and patients: Totally, 1323 glioma samples from Chinese Glioma Genome Atlas (CGGA) dataset, including 325 RNAseq data and 301 mRNA microarray data, and The Cancer Genome Atlas (TCGA) dataset, including 697 RNAseq data, were gathered into our research. The statistical analysis and graphical work were mainly realized by R language. Results: B7-H3 expression was found positively correlated with the grade of malignancy, which might be caused by hypomethylation. The expression level of B7-H3 was consistently up-regulated in IDH wild-type glioma and highly enriched in mesenchymal subtype. GSEA analysis suggested that B7-H3 related genes were more involved in immune response and angiogenesis in glioma. Moreover, B7-H3 showed a consistent positive relationship with stromal and immune cell populations. Further analysis confirmed that B7-H3 played an important role in T-cell-mediated immunity, especially in T-cell-mediated immune response to tumor cell. Circos plots revealed that B7-H3 was tightly associated with most B7 members and other immune checkpoints. Univariate and multivariate cox analysis demonstrated that B7-H3 was an independent prognosticator for glioma patients. Conclusion: B7-H3 represents the malignant phenotype of glioma and independently predicted worse prognosis in glioma patients. Moreover, B7-H3 collaborating with other checkpoint members may contribute to the dysfunctional phenotype of T cell. These findings will be helpful for further optimizing immunotherapies for glioma.

Comprehensive molecular profiling of the B7 family in gastrointestinal cancer

OBJECTIVES

B7 family has been identified as co-stimulatory or co-inhibitory molecules on T-cell response and plays an important role in tumour mortality and malignancy. In this study, the expression pattern of B7 family in gastrointestinal (GI) cancer was examined. Its upstream regulating mechanism, downstream targets and association with clinical parameters were also studied.

MATERIALS AND METHODS

The expression level of B7 members was analysed by FIREHOUSE. The gene mutation, DNA methylation, association with clinical parameters and downstream network of B7 members were analysed in cBioportal. The mutation frequency was analysed by Catalogue of Somatic Mutations in Cancer (COSMIC) analysis. The phylogenetic tree was constructed in MEGA7. The interaction protein domain analysis was performed by Pfam 31.0.

RESULTS

Differential expression of B7 family molecules was detected in different kinds of GI cancer. High-frequency gene alteration was found in tumour samples. There was negative correlation of promoter methylation and mRNA expression of B7 family members in tumour samples, suggesting the epigenetic basis of B7 family gene deregulation in GI cancer. The overexpression of B7-H1 in pancreatic cancer, B7-H5 in oesophageal cancer and B7-H6 in liver cancer were significantly associated with worse overall survival. Finally, by network analysis, we identified some potential interacting proteins for B7-1/2 and B7-H1/DC.

CONCLUSIONS

Overall, our study suggested that B7 member deregulation was strongly involved in GI cancer tumorigenesis.

B7H3 As a Promoter of Metastasis and Promising Therapeutic Target

B7H3 (also known as CD276, an immune checkpoint molecule) is aberrantly overexpressed in many types of cancer, and such upregulation is generally associated with a poor clinical prognosis. Recent discoveries indicate a crucial role for B7H3 in promoting carcinogenesis and metastasis. This review will focus on the latest developments relating specifically to the oncogenic activity of B7H3 and will describe the upstream regulators and downstream effectors of B7H3 in cancer. Finally, we discuss the emerging roles of microRNAs (miRNAs) in inhibiting B7H3-mediated tumor promotion. Excellent recent studies have shed new light on the functions of B7H3 in cancer and identified B7H3 as a critical promoter of tumor cell proliferation, migration, invasion, epithelial-to-mesenchymal transition, cancer stemness, drug resistance, and the Warburg effect. Numerous miRNAs are reported to regulate the expression of B7H3. Our meta-analysis of miRNA database revealed that 17 common miRNAs potentially interact with B7H3 mRNA. The analysis of the TCGA ovarian cancer dataset indicated that low miR-187 and miR-489 expression was associated with poor prognosis. Future studies aimed at delineating the precise cellular and molecular mechanisms underpinning B7H3-mediated tumor promotion will provide further insights into the cell biology of tumor development. In addition, inhibition of B7H3 signaling, to be used alone or in combination with other treatments, will contribute to improvements in clinical practice and benefit cancer patients.

PD-L1, B7-H3, and PD-1 expression in immunocompetent vs. immunosuppressed patients with cutaneous squamous cell carcinoma

BACKGROUND

To characterize the expression of co-signaling molecules PD-L1, PD-1, and B7-H3 in cutaneous squamous cell carcinoma (cSCC) by immune status.

METHODS

We retrospectively analyzed 66 cases of cSCC treated with surgical resection from 2012 to 2015. Immunostained tumor sections were analyzed for percent of tumor cells expressing PD-L1 (Tum-PD-L1%), B7-H3 (Tum-B7-H3%), density of peri and intratumoral CD8 T cells (CD8 density), proportion of CD8 T cells expressing PD-1 (CD8-PD-1%) and of tumor-infiltrating immune cells (TII) expressing PD-L1 (TII-PD-L1%).

RESULTS

Of 66 cases, 42 were immunocompetent, 24 immunosuppressed (13 organ transplant, 8 HIV+, 3 other). Defining positive expression at > 5%, 26% of tumors were positive for PD-L1, 85% for B7-H3, 80% had CD8 T cells that expressed PD-1 and 55% had TII that expressed PD-L1. Tum-B7-H3% was significantly higher (median 60 vs. 28%, p = 0.025) in immunocompetent vs. immunosuppressed patients, including when factoring in cause of immunosuppression. No significant difference in Tum-PD-L1%, TII-PD-L1%, CD8 density, or CD8-PD-1% was observed. Tumors from HIV+ patients lacked PD-L1 expression, and had lower B7-H3% (median 2.5 vs. 60%, p = 0.007), and higher CD8 density (median 75% vs. 40%, p = 0.04) compared to immunocompetent patients. Higher tumor grade (Rs = 0.34, p = 0.006) and LVI (Rs = 0.61, p < 0.001) were both associated with higher Tum-PD-L1%.

CONCLUSION

cSCC showed expression of PD-L1 on tumor in 26% of cases, and high tumor B7-H3 expression (85%) and PD-1 expression on CD8 TILs (80%). Tumor B7-H3 expression was significantly higher in immunocompetent vs. immunosuppressed patients, largely driven by very low expression in HIV+ patients.

B7-H3 in tumors: friend or foe for tumor immunity?

B7-H3 is a type I transmembrane co-stimulatory molecule of the B7 family. B7-H3 mRNA is widely distributed in most tissues; however, B7-H3 protein is not constitutively expressed. Few molecules have been shown to mediate the regulation of B7-H3 expression, and their regulatory mechanisms remain unexplored. Recently, TREM-like transcript 2 (TLT-2) has been identified as a potential receptor of B7-H3. However, TLT-2 may not be the only receptor of B7-H3, as B7-H3 has many contradictory roles. As a co-stimulatory molecule, B7-H3 increases the proliferation of both CD4+ and CD8+ T-cells and enhances cytotoxic T-cell activity. However, greatly increased T-cell proliferation and IL-2 levels have been observed in the absence of B7-H3. Thus far, it has been shown that various tumors test positive for B7-H3 expression and that B7-H3 levels correlate with tumor growth, invasion, metastasis, malignant stage, and recurrence rate. Furthermore, transfection of cells with a B7-H3 plasmid and treatment with monoclonal antibodies to block B7-H3 are the main immunotherapeutic strategies for cancer treatment. Several groups have generated anti-B7-H3 antibodies and observed tumor growth suppression in vitro and in vivo. Therefore, it is likely that B7-H3 plays an important role in cancer diagnosis and treatment, aside from its role as a co-stimulatory molecule.