ILT4 drives B7-H3 expression via PI3K/AKT/mTOR signalling and ILT4/B7-H3 co-expression correlates with poor prognosis in non-small cell lung cancer

Targeting leukocyte immunoglobulin‑like receptor B2 in the tumor microenvironment: A new treatment prospect for solid tumors (Review)

Leukocyte immunoglobulin-like receptor B2 (LILRB2) functions as an immunosuppressive receptor that has a prominent role in immune regulation. The expression of LILRB2 is higher in a variety of solid malignant tumors compared with that in corresponding normal tissues. LILRB2 can be expressed in tumor cells and tumor stromal cells within the tumor microenvironment. Upregulation of LILRB2 in tumors is significantly associated with a poorer tumor phenotype, increased tolerance to certain therapeutic drugs, tumor immune escape and shorter patient overall survival time. Therefore, LILRB2 can be utilized as a novel biomarker to predict the prognosis of patients with solid malignant tumors, and targeting LILRB2 may be an effective strategy for targeted cancer therapy. The present review provides a general overview of the role and mechanisms of LILRB2 in the microenvironment of solid tumors, and emphasizes the significance of targeting LILRB2 as a promising approach for tumor-specific therapy.

The AURKA inhibitor alters the immune microenvironment and enhances targeting B7-H3 immunotherapy in glioblastoma

Glioblastoma (GBM) is one of the most lethal adult brain tumors with limited effective therapeutic options. Immunotherapy targeting B7-H3 (CD276) has shown promising efficacy in the treatment of gliomas. However, the response to this treatment varies among glioma patients due to individual differences. It's necessary to find an effective strategy to improve the efficacy of targeting B7-H3 immunotherapy for nonresponders. In this study, we demonstrated a strong correlation between aurora kinase A (AURKA) and CD276 expression in glioma tissue samples. Additionally, both AURKA knockdown and overexpression resulted in parallel changes in B7-H3 expression levels in glioma cells. Mechanistically, AURKA elevated B7-H3 expression by promoting epidermal growth factor receptor (EGFR) phosphorylation, which was validated in glioma cell lines and primary GBM cells. What's more, the combination of AURKA inhibitor (alisertib) and anti-B7-H3 antibody markedly reduced tumor size and promoted CD8+ T cell infiltration and activation in mouse orthotopic syngeneic glioma models. To our knowledge, this study is the first to demonstrate AURKA-mediated B7-H3 upregulation in glioma cells; moreover, it proposes a promising therapeutic strategy combining the AURKA inhibitor alisertib with B7-H3-specific blocking mAbs.

The inhibitory effects of nimotuzumab on CD276 expression and immune escape in head and neck squamous cell carcinoma: Insights into anticancer mechanisms

CD276 has been identified as a novel immune checkpoint, and its overexpression is associated with immune evasion and poor prognosis in various tumors, including head and neck squamous cell carcinoma (HNSCC). Nimotuzumab, a humanized anti-epidermal growth factor receptor (EGFR) monoclonal antibody, has been approved for various solid tumors. However, it remains unclear whether its anticancer efficacy involves a reduction in CD276 expression. The purpose of this study was to investigate the regulatory effects and potential mechanisms of nimotuzumab on CD276 expression both in vitro and in vivo. In a coculture system, nimotuzumab showed inhibitory effects on TGF-β-induced upregulation of CD276 at both the transcriptional and protein levels in HNSCC cell lines. Mechanistic studies revealed that nimotuzumab primarily suppressed TGF-β-induced CD276 upregulation by blocking EGFR/MEK/ERK, which was further validated by MEK and ERK inhibitors. In xenograft and mice HNSCC models, nimotuzumab exerted antitumor effects accompanied by significantly reduced CD276 expression during tumor progression. Analysis of tumor-infiltrating lymphocytes (TILs) profiles indicated that nimotuzumab orchestrated the tumor immune microenvironment (TIME) by notably increasing the frequency of T lymphocytes, including cytotoxic T lymphocytes and helper T lymphocytes, as well as macrophage cells. However, no significant changes were observed in the populations of NK cells, DC cells, and neutrophils. These findings offer new insights into the anticancer mechanisms of nimotuzumab and its underlying synergy in combined treatments with immunotherapy for HNSCC.

Leukocyte immunoglobulin-like receptor B4 (LILRB4) in acute myeloid leukemia: From prognostic biomarker to immunotherapeutic target

ABSTRACT

Leukocyte immunoglobulin-like receptor (LILR) B4 (also known as ILT3/CD85k) is an immune checkpoint protein that is highly expressed in solid tumors and hematological malignancies and plays a significant role in the pathophysiology of cancer. LILRB4 is highly expressed in acute myeloid leukemia (AML), and this phenotype is associated with adverse patient outcomes. Its differential expression in tumors compared to normal tissues, its presence in tumor stem cells, and its multifaceted roles in tumorigenesis position it as a promising therapeutic target in AML. Currently, several immunotherapies targeting LILRB4 are undergoing clinical trials. This review summarizes advancements made in the study of LILRB4 in AML, focusing on its structure, ligands, expression, and significance in normal tissues and AML; its protumorigenic effects and mechanisms in AML; and the application of LILRB4-targeted therapies in AML. These insights highlight the potential advantages of LILRB4 as an immunotherapeutic target in the context of AML.

An integrated pan-cancer assessment of prognosis, immune infiltration, and immunotherapy response for B7 family using multi-omics data

AIMS

B7 molecules (B7s) are crucial synergistic signals for effective immune surveillance against tumor cells. While previous studies have explored the association between the B7 family and cancer, most have been limited to specific genes or cancer subtypes.

MAIN METHODS

Our study utilized multi-omics data to investigate potential correlations between B7s expression (B7s exp.) and prognosis, clinicopathological features, somatic mutations (SMs), copy number variations (CNVs), immune characteristics, tumor microenvironment (TME), microsatellite instability, tumor mutation burden, immune checkpoint gene (ICG), and drug responsiveness in TCGA tumors. Furthermore, the connection between B7s exp. and immunotherapy (IT) performance assessed in various validated datasets. Following this, immune infiltration analysis (IIA) was conducted based on B7s exp., CNVs, or SMs in bladder cancer (BLCA), complemented by real-time PCR (RT-PCR) and protein confirmation of B7-H3.

KEY FINDINGS

Across most cancer types, B7s exp. was related to prognosis, clinicopathological characteristics, mutations, CNVs, ICG, TMB, TME. The examination of sensitivity to anticancer drugs unveiled correlations between B7 molecules and different drug sensitivities. Specific B7s exp. patterns were linked to the clinical effectiveness of IT. Using GSEA, several enriched immune-related functions and pathways were identified. Particularly in BLCA, IIA revealed significant connections between B7 CNVs, mutation status, and various immune cell infiltrates. RT-PCR confirmed elevated B7-H3 gene levels in BLCA tumor tissues.

SIGNIFICANCE

This study confirmed the significance of B7s exp. and genomic changes in predicting outcomes and treatment across different cancer types. Moreover, they indicate a critical function of B7s in BLCA and their potential as IT biomarkers.

Small Extracellular Vesicle piR-hsa-30937 Derived from Pancreatic Neuroendocrine Neoplasms Upregulates CD276 in Macrophages to Promote Immune Evasion

The role of PIWI-interacting RNAs (piRNA) in small extracellular vesicles (sEV) derived from pancreatic neuroendocrine neoplasms (PNEN) in the tumor microenvironment (TME) remains unexplored. We used multiplex IHC to analyze the expression of CD68, CD276 (B7H3), and CD3 on PNEN. CD276+ tumor-associated macrophages (TAM) were more abundant in tumor tissues than nontumor tissues and negatively correlated with T-cell infiltration. Serum sEV piRNA sequencing was performed to identify piRNAs enriched in patients with PNEN. We then investigated the function and mechanism of sEV piR-hsa-30937 in the cross-talk between tumor cells and macrophages in the PNEN TME. PNEN-derived sEV piR-hsa-30937 targeted PTEN to activate the AKT pathway and drive CD276 expression. CD276+ macrophages inhibited T-cell proliferation and IFNγ production. piR-hsa-30937 knockdown and anti-CD276 treatment suppressed progression and metastasis in a preclinical model of PNEN by enhancing T-cell immunity. Thus, our data show that PNEN-derived sEV piR-hsa-30937 promotes CD276 expression in macrophages through the PTEN/AKT pathway and that CD276+ TAMs suppress T-cell antitumor immunity. sEV piR-hsa-30937 and CD276 are potential therapeutic targets for immunotherapy of PNEN.

Fully human anti-B7-H3 recombinant antibodies inhibited tumor growth by increasing T cell infiltration

Mortality due to malignant tumors is one of the major factors affecting the life expectancy of the global population. Therapeutic antibodies are a cutting-edge treatment method for restricting tumor growth. B7-H3 is highly expressed in tumor tissues, but rarely in normal tissues. B7-H3 is closely associated with poor prognosis in patients with tumors. B7-H3 is an important target for antitumor therapy. In this study, the fully human anti-B7H3 single-chain antibodies (scFvs) were isolated and screened from the fully human phage immune library with B7H3 as the target. The antibodies screened from a fully human phage library had low immunogenicity and high affinity, which was more beneficial for clinical application. Leveraging B7-H3 scFvs as a foundation, we constructed two distinct recombinant antibody formats, scFv-Fc and IgG1, characterized by elevated affinity and a prolonged half-life. The results demonstrated that the recombinant antibodies had high specificity and affinity for the B7-H3 antigen and inhibited tumor cell growth by enhancing the ADCC. After treatment with anti-B7H3 recombinant antibody, the number of infiltrating T cells in the tumor increased and the secretion of IFN- γ by infiltrating T cells increased in vivo. Additionally, the use of pleural fluid samples obtained from tumor-afflicted patients revealed the ability of anti-B7-H3 recombinant antibodies to reverse CD8+ T cell exhaustion. In summary, we screened the fully human anti-B7H3 recombinant antibodies with specificity and high affinity that increase immune cell infiltration and IFN-γ secretion, thereby inhibiting tumor cell growth to a certain extent. This finding provides a theoretical basis for the development of therapeutic tumor antibodies and could help promote further development of antibody-based drugs.

CD276 promotes epithelial-mesenchymal transition in esophageal squamous cell carcinoma through the TGF-β/SMAD signaling

OBJECTIVE

Aberrant expression of CD276 has been reported in malignant tumors. However, the exact role and mechanisms of CD276 influence the progression of esophageal squamous cell carcinoma (ESCC) still need to be understood.

METHODS

Bioinformatics analysis of data from The Cancer Genome Atlas and Gene Expression Omnibus databases, along with immunohistochemistry staining, was used to explore the expression patterns of CD276 in ESCC. Cell counting kit-8 and Transwell assays were employed to evaluate the effects of CD276 expression on tumor cell proliferation and motility. Western blotting and Transwell assays were used to explore the potential pathways through which CD276 mediates the progression of ESCC. Moreover, the in vivo role of CD276 in tumor progression was investigated by establishing a lung metastasis mouse model.

RESULTS

A significant upregulation of CD276 was observed in ESCC tissues compared to adjacent tissues. The inhibition of CD276 had no evident impact on ESCC cell proliferation but notably hindered their migratory and invasive properties and the expression of epithelial-mesenchymal transition (EMT) markers. Inversely, overexpressing CD276 led to an upregulation of EMT markers, underscoring the capacity of CD276 to amplify the motility of ESCC cells. Furthermore, CD276 was found to enhance the migratory and invasive abilities of ESCC cells by activating the TGF-β/SMAD signaling but not the PI3K/AKT pathway. In vivo studies demonstrated that CD276 facilitates pulmonary metastasis.

CONCLUSION

CD276 is significant upregulation in ESCC tissues and facilitates the EMT process in ESCC cells via the TGF-β/SMAD signaling, thus promoting the progression of ESCC.

N6-methyladenosine modification of B7-H3 mRNA promotes the development and progression of colorectal cancer

B7-H3 is a common oncogene found in various cancer types. However, the molecular mechanisms underlying abnormal B7-H3 expression and colorectal cancer (CRC) progression need to be extensively explored. B7-H3 was upregulated in human CRC tissues and its abnormal expression was correlated with a poor prognosis in CRC patients. Notably, gain- and loss-of-function experiments revealed that B7-H3 knockdown substantially inhibited cell proliferation, migration, and invasion in vitro, whereas exogenous B7-H3 expression yielded contrasting results. In addition, silencing of B7-H3 inhibited tumor growth in a xenograft mouse model. Mechanistically, our study demonstrated that the N6-methyladenosine (m6A) binding protein YTHDF1 augmented B7-H3 expression in an m6A-dependent manner. Furthermore, rescue experiments demonstrated that reintroduction of B7-H3 considerably abolished the inhibitory effects on cell proliferation and invasion induced by silencing YTHDF1. Our results suggest that the YTHDF1-m6A-B7-H3 axis is crucial for CRC development and progression and may represent a potential therapeutic target for CRC treatment.

Soluble B7-H3 in Colorectal Cancer

We present the results of comparative ELISA of the concentration of soluble form of immunity checkpoint B7-H3 (sB7-H3) in the serum of patients with colorectal cancer (CRC) at different stages before treatment and healthy control donors. The analysis revealed a statistically significant difference between the median levels of sB7-H3 in the blood serum of CRC patients (19.66 ng/ml) and healthy donors (16.76 ng/ml) (p=0.0025). ROC analysis showed 62.9% sensitivity and 56.7% specificity for CRC patients (cut-off 17.62 ng/ml; p=0.0028). An association of sB7-H3 levels with tumor progression was revealed. We demonstrated that sB7-H3 levels were significantly lower in patients with regional metastases than in patients without metastases (p=0.039) and that sB7-H3 concentration tends to decrease at the late stages of the disease. Thus, high serum level of sB7-H3 in CRC patients can be a favorable prognostic factor in future.

ILT4 reprograms glucose metabolism to promote tumor progression in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is the most aggressive and poorly treated subtype of breast cancer. Identifying novel drivers and mechanisms for tumor progression is essential for precise targeted therapy of TNBC. Immunoglobulin-like transcript 4 (ILT4; also known as LILRB2) is a classic myeloid suppressor for their activation and immune response. Our recent results found that ILT4 is also highly expressed in lung cancer cells, where it has a role in promoting immune evasion and thus tumor formation. However, the expression and function of ILT4 in breast cancer remains elusive. Here, using our patient cohort and public database analysis, we found that TNBC displayed the most abundant ILT4 expression among all breast cancer subtypes. Functionally, enriched ILT4 promoted TNBC cell proliferation, migration and invasion in vitro, as well as tumor growth and metastasis in vivo. Further mechanistic analysis revealed that ILT4 reprogrammed aerobic glycolysis of tumor cells via AKT-mTOR signaling-mediated glucose transporter 3 (GLUT3; also known as SLC2A3) and pyruvate kinase muscle 2 (PKM2, an isoform encoded by PKM) overexpression. ILT4 inhibition in TNBC reduced tumor progression and GLUT3 and PKM2 expression in vivo. Our study identified a novel driver for TNBC progression and proposed a promising strategy to combat TNBC by targeting ILT4.

Immunohistochemical analysis of B7-H3 expression in patients with lung cancer following various anti-cancer treatments

B7 homolog 3 protein (B7-H3), an immune checkpoint molecule belonging to the B7 family, has been studied as a target for the development of anti-cancer treatment; however, changes in B7-H3 expression during the clinical course remain unknown. This retrospective study aimed to investigate changes in B7-H3 expression of lung cancer specimens in patients with advanced lung cancer following various anti-cancer treatments. The immunohistochemistry (IHC) score was evaluated on a 0-3 scale, and B7-H3 expression was considered positive for grade ≥ 2. The difference in IHC scores before and after anti-cancer treatment was defined as the change in B7-H3 expression. Among 160 patients with lung cancer who received anti-cancer treatment, 88 (55%) and 101 (63%) had B7-H3 expression before and after anti-cancer treatment, respectively. Before treatment, B7-H3 expression was significantly more common in squamous cell carcinoma specimens than in adenocarcinoma specimens (95% vs. 49%, P < 0.001). Of the 19 patients with squamous cell carcinoma, 18 (95%) continued to have high (IHC score: 3) B7-H3 expression following treatment. In contrast, of the 130 patients with adenocarcinoma, 46 (35%) and 17 (13%) showed an increased and a decreased expression, respectively. Patients who received targeted therapy had a significant increase in B7-H3 expression compared with those who received chemotherapy alone (P = 0.015). Overall, squamous cell carcinoma specimens maintained high B7-H3 expression during the clinical course, whereas adenocarcinoma specimens showed changes in expression following anti-cancer treatments. Our results provide the basis for further studies on the development of anti-cancer treatments targeting B7-H3.

mTORC1 upregulates B7-H3/CD276 to inhibit antitumor T cells and drive tumor immune evasion

Identifying the mechanisms underlying the regulation of immune checkpoint molecules and the therapeutic impact of targeting them in cancer is critical. Here we show that high expression of the immune checkpoint B7-H3 (CD276) and high mTORC1 activity correlate with immunosuppressive phenotypes and worse clinical outcomes in 11,060 TCGA human tumors. We find that mTORC1 upregulates B7-H3 expression via direct phosphorylation of the transcription factor YY2 by p70 S6 kinase. Inhibition of B7-H3 suppresses mTORC1-hyperactive tumor growth via an immune-mediated mechanism involving increased T-cell activity and IFN-γ responses coupled with increased tumor cell expression of MHC-II. CITE-seq reveals strikingly increased cytotoxic CD38+CD39+CD4+ T cells in B7-H3-deficient tumors. In pan-human cancers, a high cytotoxic CD38+CD39+CD4+ T-cell gene signature correlates with better clinical prognosis. These results show that mTORC1-hyperactivity, present in many human tumors including tuberous sclerosis complex (TSC) and lymphangioleiomyomatosis (LAM), drives B7-H3 expression leading to suppression of cytotoxic CD4+ T cells.

New frontiers in immune checkpoint B7-H3 (CD276) research and drug development

B7-H3 (CD276), a member of the B7 family of proteins, is a key player in cancer progression. This immune checkpoint molecule is selectively expressed in both tumor cells and immune cells within the tumor microenvironment. In addition to its immune checkpoint function, B7-H3 has been linked to tumor cell proliferation, metastasis, and therapeutic resistance. Furthermore, its drastic difference in protein expression levels between normal and tumor tissues suggests that targeting B7-H3 with drugs would lead to cancer-specific toxicity, minimizing harm to healthy cells. These properties make B7-H3 a promising target for cancer therapy.Recently, important advances in B7-H3 research and drug development have been reported, and these new findings, including its involvement in cellular metabolic reprograming, cancer stem cell enrichment, senescence and obesity, have expanded our knowledge and understanding of this molecule, which is important in guiding future strategies for targeting B7-H3. In this review, we briefly discuss the biology and function of B7-H3 in cancer development. We emphasize more on the latest findings and their underlying mechanisms to reflect the new advances in B7-H3 research. In addition, we discuss the new improvements of B-H3 inhibitors in cancer drug development.

Multi-omics analyses of CD276 in pan-cancer reveals its clinical prognostic value in glioblastoma and other major cancer types

BACKGROUND

CD276 (also known as B7-H3) is one of the most important immune checkpoints of the CD28 and B7 superfamily, and its abnormal expression is closely associated with various types of cancer. It has been shown that CD276 is able to inhibit the function of T cells, and that this gene may potentially be a promising immunotherapy target for different types of cancer.

METHODS

Since few systematic studies have been published on the role of CD276 in cancer to date, the present study has employed single-cell sequencing and bioinformatics methods to analyze the expression patterns, clinical significance, prognostic value, epigenetic alterations, DNA methylation level, tumor immune cell infiltration and immune functions of CD276 in different types of cancer. In order to analyze the potential underlying mechanism of CD276 in glioblastoma (GBM) to assess its prognostic value, the LinkedOmics database was used to explore the biological function and co-expression pattern of CD276 in GBM, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed. In addition, a simple validation of the above analyses was performed using reverse transcription-quantitative (RT-q)PCR assay.

RESULTS

The results revealed that CD276 was highly expressed, and was often associated with poorer survival and prognosis, in the majority of different types of cancer. In addition, CD276 expression was found to be closely associated with T cell infiltration, immune checkpoint genes and immunoregulatory interactions between lymphoid and a non-lymphoid cell. It was also shown that the CD276 expression network exerts a wide influence on the immune activation of GBM. The expression of CD276 was found to be positively correlated with neutrophil-mediated immunity, although it was negatively correlated with the level of neurotransmitters, neurotransmitter transport and the regulation of neuropeptide signaling pathways in GBM. It is noteworthy that CD276 expression was found to be significantly higher in GBM compared with normal controls according to the RT-qPCR analysis, and the co-expression network, biological function and chemotherapeutic drug sensitivity of CD276 in GBM were further explored. In conclusion, the findings of the present study have revealed that CD276 is strongly expressed and associated with poor prognosis in most types of cancer, including GBM, and its expression is strongly associated with T-cell infiltration, immune checkpoint genes, and immunomodulatory interactions between lymphocytes and non-lymphoid cells.

CONCLUSIONS

Taken together, based on our systematic analysis, our findings have revealed important roles for CD276 in different types of cancers, especially GBM, and CD276 may potentially serve as a biomarker for cancer.

Gastric cancer-derived mesenchymal stem cells promote gastric cancer cell lines migration by modulating CD276 expression

CD276 has been studied in a variety of cancers and diseases, but its regulatory mechanisms in gastric cancer is still unclear. Mesenchymal stem cells (MSCs), one of the important members of tumor microenvironment, play an important role in the occurrence, development and metastasis of tumor, but the relationship between gastric cancer mesenchymal stem cells (GCMSCs) and CD276 in gastric cancer needs to be further explored. The differential expression of CD276 was identified via UCLAN and GEPIA databases. Then, the impacts of CD276 were calculated on clinical prognosis using the Kaplan-Meier plotter and Cox analysis. GO, KEGG and GSEA analysis were used to explore potential mechanism under CD276. Next, the expression of CD276 in gastric cell lines were detected by Western blot. Immunocoprecipitation was used to explore the association between CD276 and COL1A1. And the effect of condition medium (CM) from GCMSCs on gastric cell lines migration analyzed. GC-MSCs activated the AKT/c-Myc/mTOR pathway of gastric cell lines and upregulated CD276 expression. Moreover, the upregulation of CD276 promoted the migration of gastric cancer cells. Taken together, this study shown that GCMSCs could up-regulate the expression of CD276 of gastric cell lines to promote tumor migration. Our results provide a new basis for the treatment of gastric cancer.

The Role of Leukocyte Immunoglobulin-Like Receptors Focusing on the Therapeutic Implications of the Subfamily B2

The leukocyte immunoglobulin (Ig)-like receptors (LILRs) are constituted by five inhibitory subpopulations (LILRB1-5) and six stimulatory subpopulations (LILRA1-6). The LILR populations substantially reside in immune cells, especially myeloid cells, functioning as a regulator in immunosuppressive and immunostimulatory responses, during which the nonclassical major histocompatibility complex (MHC) class I molecules are widely involved. In addition, LILRs are also distributed in certain tumor cells, implicated in the malignancy progression. Collectively, the suppressive Ig-like LILRB2 is relatively well-studied to date. Herein, we summarized the whole family of LILRs and their biologic function in various diseases upon ligation to the critical ligands, therefore providing more information on their potential roles in these pathological processes and giving the clinical significance of strategies targeting LILRs.

To kill a cancer: Targeting the immune inhibitory checkpoint molecule, B7-H3

Targeting the anti-tumor immune response via the B7 family of immune-regulatory checkpoint proteins has revolutionized cancer treatment and resulted in punctuated responses in patients. B7-H3 has gained recent attention given its prominent deregulation and immunomodulatory role in a multitude of cancers. Numerous cancer studies have firmly established a strong link between deregulated B7-H3 expression and poorer outcomes. B7-H3 has been shown to augment cancer cell survival, proliferation, metastasis, and drug resistance by inducing an immune evasive phenotype through its effects on tumor-infiltrating immune cells, cancer cells, cancer-associated vasculature, and the stroma. Given the complex interplay between each of these components of the tumor microenvironment, a deeper understanding of B7-H3 signaling properties is inherently crucial to developing efficacious therapies that can target and inhibit these cancer-promoting interactions. This review delves into the various ways B7-H3 acts as an immunomodulator to facilitate immune evasion and promote tumor growth and spread. With post-transcriptional and post-translational modifications giving rise to different active isoforms coupled with recent discoveries of its putative receptors, B7-H3 can perform diverse functions. Here, we first discuss the dual co-stimulatory/co-inhibitory functions of B7-H3 in the context of normal physiology and cancer. We then discuss the crosstalk facilitated by B7-H3 between stromal components and tumor cells that promote tumor growth and metastasis in different populations of tumor cells, associated vasculature, and the stroma. Concurrently, we highlight therapeutic strategies that can exploit these interactions and their associated limitations, concluding with a special focus on the promise of next-gen in silico-based approaches to small molecule inhibitor drug discovery for B7-H3 that may mitigate these limitations.

Genome-scale CRISPR-Cas9 screen reveals novel regulators of B7-H3 in tumor cells

Background

Despite advances in B7 homolog 3 protein (B7-H3) based immunotherapy, the development of drug resistance remains a major clinical concern. The heterogeneity and emerging loss of B7-H3 expression are the main causes of drug resistance and treatment failure in targeted therapies, which reveals an urgent need to elucidate the mechanism underlying the regulation of B7-H3 expression. In this study, we identified and explored the crucial role of the transcription factor SPT20 homolog (SP20H) in B7-H3 expression and tumor progression.

Methods

Here, we performed CRISPR/Cas9-based genome scale loss-of-function screening to identify regulators of B7-H3 in human ovarian cancer cells. Signaling pathways altered by SP20H knockout were revealed by RNA sequencing. The regulatory role and mechanism of SP20H in B7-H3 expression were validated using loss-of-function and gain-of-function assays in vitro. The effects of inhibiting SP20H on tumor growth and efficacy of anti-B7-H3 treatment were evaluated in tumor-bearing mice.

Results

We identified SUPT20H (SP20H) as negative and eIF4E as positive regulators of B7-H3 expression in various cancer cells. Furthermore, we provided evidence that either SP20H loss or TNF-α stimulation in tumor cells constitutively activates p38 MAPK-eIF4E signaling, thereby upregulating B7-H3 expression. Loss of SP20H upregulated B7-H3 expression both in vitro and in vivo. Additionally, deletion of SP20H significantly suppressed tumor growth and increased immune cells infiltration in tumor microenvironment. More importantly, antibody–drug conjugates targeting B7-H3 exhibited superior antitumor performance against SP20H-deficient tumors relative to control groups.

Conclusions

Activation of p38 MAPK-eIF4E signaling serves as a key event in the transcription initiation and B7-H3 protein expression in tumor cells. Genetically targeting SP20H upregulates target antigen expression and sensitizes tumors to anti-B7-H3 treatment. Collectively, our findings provide new insight into the mechanisms underlying B7-H3 expression and introduce a potential synergistic target for existing antibody-based targeted therapy against B7-H3.

Targeted Therapy of B7 Family Checkpoints as an Innovative Approach to Overcome Cancer Therapy Resistance: A Review from Chemotherapy to Immunotherapy

It is estimated that there were 18.1 million cancer cases worldwide in 2018, with about 9 million deaths. Proper diagnosis of cancer is essential for its effective treatment because each type of cancer requires a specific treatment procedure. Cancer therapy includes one or more approaches such as surgery, radiotherapy, chemotherapy, and immunotherapy. In recent years, immunotherapy has received much attention and immune checkpoint molecules have been used to treat several cancers. These molecules are involved in regulating the activity of T lymphocytes. Accumulated evidence shows that targeting immune checkpoint regulators like PD-1/PD-L1 and CTLA-4 are significantly useful in treating cancers. According to studies, these molecules also have pivotal roles in the chemoresistance of cancer cells. Considering these findings, the combination of immunotherapy and chemotherapy can help to treat cancer with a more efficient approach. Among immune checkpoint molecules, the B7 family checkpoints have been studied in various cancer types such as breast cancer, myeloma, and lymphoma. In these cancers, they cause the cells to become resistant to the chemotherapeutic agents. Discovering the exact signaling pathways and selective targeting of these checkpoint molecules may provide a promising avenue to overcome cancer development and therapy resistance. Highlights: (1) The development of resistance to cancer chemotherapy or immunotherapy is the main obstacle to improving the outcome of these anti-cancer therapies. (2) Recent investigations have described the involvement of immune checkpoint molecules in the development of cancer therapy resistance. (3) In the present study, the molecular participation of the B7 immune checkpoint family in anticancer therapies has been highlighted. (4) Targeting these immune checkpoint molecules may be considered an efficient approach to overcoming this obstacle.

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 of leukocyte immunoglobulin-like receptor subfamily B expression on immune cells in hepatocellular carcinoma

BACKGROUND

Leukocyte immunoglobulin-like receptor subfamily B (LILRB) is a group of inhibitory receptors involved in innate immune mainly expressed on lymphoid and myelomonocytic cells. LILRB is proposed to serve as immune checkpoint like PD-1 and CTLA-4 for tumor treatment. We recently reported that the expression of LILRB2 in CD1c⁺ mDC from tumor tissue might suppress immune for HCC patients. However, the expression of all the LILRB family on other immune cells in peripheral blood and tumor microenvironment of HCC patients has not been systematically studied.

METHODS

The expression of LILRB family (LILRB1, LILRB2, LILRB3, LILRB4 and LILRB5) on immune cells, including granulocytes, NK cells, NKT cells, monocyte subsets, TAMs, B cells, γδ T cells, CD4⁺ T cells, CD8⁺ T cells and MDSC subsets, was analyzed by flow cytometry in the peripheral blood of 20 HCC patients and 20 healthy donors as well as in the tumor and tumor free tissues of 10 HCC patients.

RESULTS

LILRB1, LILRB2 and LILRB3 in granulocytes from peripheral blood were expressed increased in HCC patients compared with healthy donors. The expression of LILRB5 in NK cells and NKT cells from HCC blood were higher compared with healthy donors` blood. CD14⁺CD16⁺ monocyte subsets in blood of HCC patients expressed increased LILRB1 and LILRB4 than that in healthy donors. CD14⁺CD16^- monocyte subsets in blood of HCC patients expressed increased LILRB3 than that in healthy donors. Compared to corresponding TFL, LILRB3, LILRB4 and LILRB5 were expressed enhanced in TAMs from HCC tumors. LILRB1 expressed on the B cells both in the blood and tumor had significantly increased compared with healthy donors or corresponding TFL. Different from peripheral blood, in the HCC microenvironment, CD4⁺ T cells expressed lower LILRB2, LILRB3 and LILRB4 than that from TFL and CD8⁺ T cells expressed decreased LILRB2. And γδ T cells expressed LILRB1 in HCC blood and microenvironment. Surprisingly, the percentage of LILRB1 expressed on MDSC from HCC peripheral blood and tumors was lower than that from healthy donors and corresponding TFL.

CONCLUSIONS

This is the first systemically examination of the LILRB family expression on a variety of immune cells from both peripheral blood and microenvironment in HCC patients. The specific increasing expression of LILRB on immune cells may regulate innate and adaptive immune and impact on HCC progression. Our findings justify further investigation of LILRB function in HCC.

Clinical Insights Into Novel Immune Checkpoint Inhibitors

The success of immune checkpoint inhibitors (ICIs), notably anti-cytotoxic T lymphocyte associated antigen-4 (CTLA-4) as well as inhibitors of CTLA-4, programmed death 1 (PD-1), and programmed death ligand-1 (PD-L1), has revolutionized treatment options for solid tumors. However, the lack of response to treatment, in terms of de novo or acquired resistance, and immune related adverse events (IRAE) remain as hurdles. One mechanisms to overcome the limitations of ICIs is to target other immune checkpoints associated with tumor microenvironment. Immune checkpoints such as lymphocyte activation gene-3 (LAG-3), T cell immunoglobulin and ITIM domain (TIGIT), T cell immunoglobulin and mucin-domain containing-3 (TIM-3), V-domain immunoglobulin suppressor of T cell activation (VISTA), B7 homolog 3 protein (B7-H3), inducible T cell costimulatory (ICOS), and B and T lymphocyte attenuator (BTLA) are feasible and promising options for treating solid tumors, and clinical trials are currently under active investigation. This review aims to summarize the clinical aspects of the immune checkpoints and introduce novel agents targeting these checkpoints.

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.

Analysis of Intra-Tumoral Macrophages and T Cells in Non-Small Cell Lung Cancer (NSCLC) Indicates a Role for Immune Checkpoint and CD200-CD200R Interactions

Non-small cell lung carcinoma (NSCLC) is one of the most commonly diagnosed cancers and a leading cause of cancer-related deaths. Immunotherapy with immune checkpoint inhibitors shows beneficial responses, but only in a proportion of patients. To improve immunotherapy in NSCLC, we need to map the immune checkpoints that contribute immunosuppression in NSCLC-associated immune cells and to identify novel pathways that regulate immunosuppression. Here, we investigated the gene expression profiles of intra-tumoral immune cells isolated from NSCLC patients and compared them to the expression profiles of their counterparts in adjacent healthy tissue. Transcriptome analysis was performed on macrophages, CD4+ and CD8+ T cells. The data was subjected to Gene Ontology (GO) term enrichment and weighted correlation network analysis in order to identify mediators of immunosuppression in the tumor microenvironment in NSCLC. Immune cells from NSCLC revealed a consistent differential expression of genes involved in interactions between myeloid cells and lymphocytes. We further identified several immunosuppressive molecules and pathways that may be activated in tumor-associated macrophages in NSCLC. Importantly, we report novel data on immune cell expression of the newly described CD200/CD200R1 pathway, and the leukocyte immunoglobulin-like receptors (LILRs), which may represent novel innate immune checkpoints, dampening the anti-tumor T cell immune response in NSCLC. Our study substantiates the importance of tumor-associated macrophages as a mediator of immunosuppression and a promising target for immunotherapy.

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.

Leukocyte immunoglobulin-like receptor subfamily B: therapeutic targets in cancer

Inhibitory leukocyte immunoglobulin-like receptors (LILRBs 1–5) transduce signals via intracellular immunoreceptor tyrosine-based inhibitory motifs that recruit phosphatases to negatively regulate immune activation. The activation of LILRB signaling in immune cells may contribute to immune evasion. In addition, the expression and signaling of LILRBs in cancer cells especially in certain hematologic malignant cells directly support cancer development. Certain LILRBs thus have dual roles in cancer biology—as immune checkpoint molecules and tumor-supporting factors. Here, we review the expression, ligands, signaling, and functions of LILRBs, as well as therapeutic development targeting them. LILRBs may represent attractive targets for cancer treatment, and antagonizing LILRB signaling may prove to be effective anti-cancer strategies.

B7-H3 is spliced by SRSF3 in colorectal cancer

B7-H3, an important co-inhibitor, is abnormally highly expressed in a variety of malignancies. The antibodies targeting B7-H3 have exhibited beneficial therapeutic effects in clinical trials. Therefore, discovery of the regulatory factors in B7-H3 expression may provide new strategies for tumor therapy. Here, we investigated the splicing factors involved in the splicing of B7-H3. By individual knockdown of the splicing factors in colorectal cancer (CRC) cells, we found that B7-H3 expression was markedly inhibited by SRSF3 and SRSF8, especially SRSF3. Then we found that both SRSF3 and B7-H3 were highly expressed in CRC tissues. Moreover, high-expression of either SRSF3 or B7-H3 was significantly correlated with poor prognosis of patients. The expression of B7-H3 mRNA and protein were evidently reduced by SRSF3 silence, but were enhanced by overexpression of SRSF3 in both HCT-116 and HCT-8 cells. The results from the RNA immunoprecipitation (RIP) assays demonstrated that SRSF3 protein directly binds to B7-H3 mRNA. In addition, we constructed a minigene recombinant plasmid for expressing B7-H3 exons 3-6. We found that SRSF3 contributed to the retention of B7-H3 exon 4. These findings demonstrate that SRSF3 involves in the splicing of B7-H3 by directly binding to its exon 4 and/or 6. It may provide novel insights into the regulatory mechanisms of B7-H3 expression and potential strategies for the treatment of CRC.

The Molecular and Functional Characteristics of HLA-G and the Interaction with Its Receptors: Where to Intervene for Cancer Immunotherapy?

Human leukocyte antigen G (HLA-G) mediates maternal-fetal immune tolerance. It is also considered an immune checkpoint in cancer since it may mediate immune evasion and thus promote tumor growth. HLA-G is, therefore, a potential target for immunotherapy. However, existing monoclonal antibodies directed against HLA-G lack sufficient specificity and are not suitable for immune checkpoint inhibition in a clinical setting. For this reason, it is essential that alternative approaches are explored to block the interaction between HLA-G and its receptors. In this review, we discuss the structure and peptide presentation of HLA-G, and its interaction with the receptors Ig-like transcript (ILT) 2, ILT4, and Killer cell immunoglobulin-like receptor 2DL4 (KIR2DL4). Based on our findings, we propose three alternative strategies to block the interaction between HLA-G and its receptors in cancer immunotherapy: (1) prevention of HLA-G dimerization, (2) targeting the peptide-binding groove of HLA-G, and (3) targeting the HLA-G receptors. These strategies should be an important focus of future studies that aim to develop immune checkpoint inhibitors to block the interaction between HLA-G and its receptors for the treatment of cancer.

B7-H3: An Attractive Target for Antibody-based Immunotherapy

The recent impressive clinical responses to antibody-based immunotherapy have prompted the identification of clinically relevant tumor antigens that can serve as targets in solid tumors. Among them, B7-H3, a member of the B7 ligand family, represents an attractive target for antibody-based immunotherapy, it is overexpressed on differentiated malignant cells and cancer-initiating cells, with limited heterogeneity, and high frequency (60% of 25,000 tumor samples) in many different cancer types, but has a limited expression at low level in normal tissues. In nonmalignant tissues, B7-H3 has a predominantly inhibitory role in adaptive immunity, suppressing T-cell activation and proliferation. In malignant tissues, B7-H3 inhibits tumor antigen-specific immune responses, leading to a protumorigenic effect. B7-H3 also has nonimmunologic protumorigenic functions, such as promoting migration and invasion, angiogenesis, chemoresistance, and endothelial-to-mesenchymal transition, as well as affecting tumor cell metabolism. As a result, B7-H3 expression in tumors is associated with poor prognosis. Although experimental B7-H3 silencing reduces cancer cell malignant potential, there has been limited emphasis on the development of B7-H3-blocking antibodies, most likely because the B7-H3 receptor remains unknown. Instead, many antibody-based strategies utilizing distinct effector mechanisms to target B7-H3-expressing cancer cells have been developed. These strategies have demonstrated potent antitumor activity and acceptable safety profiles in preclinical models. Ongoing clinical trials are assessing their safety and efficacy in patients. Identification of the B7-H3 receptor will improve our understanding of its role in tumor immunity, and will suggest rational strategies to develop blocking antibodies, which may enhance the therapeutic efficacy of tumor immunity.

B7-H3 expression in upper tract urothelial carcinoma associates with adverse clinicopathological features and poor survival

B7-H3, a member of the B7 superfamily, is an immune checkpoint molecule. An association between B7-H3 expression and poor survival has been reported in many types of cancer. However, its prognostic value in patients with upper tract urothelial carcinoma (UTUC) has not yet been reported. The aim of this study was to examine the clinical significance of tumor B7-H3 expression in UTUC. B7-H3 positivity was observed in 36 of 271 cases (13 %) by immunohistochemistry and was significantly associated with several adverse clinicopathological features such as tumor grade, tumor stage, and lymph node metastasis. In addition, B7-H3 positivity was significantly associated with shorter metastasis-free survival and cancer-specific survival. We also found that B7-H3/programmed cell death ligand-1 (PD-L1) co-positivity was significantly associated with worse prognosis. These results suggest the utility of B7-H3 positivity and B7-H3/PD-L1 co-positivity as novel prognostic biomarkers in UTUC, and the potential usefulness of B7-H3 targeted therapy for patients with UTUC, the effect of which may be enhanced by combination with programmed cell death-1 /PD-L1 blockade.

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.

High B7-H3 expression is linked to increased risk of prostate cancer progression

B7-H3 is a member of the B7 superfamily of immune checkpoint molecules. B7-H3 up regulation has been linked to cancer development and progression in many tumors including prostate cancer. To clarify the potential utility of B7-H3 as a prognostic biomarker, B7-H3 expression was analyzed by immunohistochemistry in more than 17 000 prostate cancers. Normal prostatic glands were largely B7-H3 negative, while membranous B7-H3 immunostaining was seen in 47.0% of analyzed cancers. B7-H3 immunostaining was weak in 12.3%, moderate in 21.1% and strong in 13.5% of cases. High B7-H3 expression was associated with pT, Gleason score, lymph node metastasis, high Ki67 labeling index and early prostate-specific antigen recurrence (P < 0.0001 each). High B7-H3 expression was also linked to high androgen receptor expression and TMPRSS2:V-ets avian erythroblastosis virus E26 oncogene homolog (ERG) fusions (P < 0.0001 each). Multivariate analyses showed a strong independent prognostic impact of high B7-H3 expression in all cancers and in the ERG negative subgroup. Comparison with previously analyzed frequent chromosomal deletions revealed a close association with Phosphatase and Tensin Homolog deletions. Analysis of B7-H3, alone or in combination with other markers, might be of clinical utility, especially in the subgroup of ERG negative prostate cancers.

B7-H3, a checkpoint molecule, as a target for cancer immunotherapy

B7-H3 (also known as CD276) is a newly found molecule of B7 family, which may be a promising target for cancer treatment. B7-H3 protein was demonstrated to be expressed in several kinds of tumor tissues including non-small-cell lung cancer (NSCLC) and prostate cancer. Its expression is highly associated with undesirable treatment outcomes and survival time, due to function of the immune checkpoint molecule. It was classified as either a co-stimulatory molecule for T cell activation or the nonimmunological role of regulating signaling pathways. Although there is still no agreed conclusion on the function of B7-H3, it may be a valuable target for cancer therapy. This review aims to provide a comprehensive, up-to-date summary of the advances in B7-H3 targeting approaches in cancer therapy. Although several challenges remain, B7-H3 offers a new therapeutic target with increased efficacy and less toxicity in future cancer treatment.

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.

B7-H3 promotes colorectal cancer angiogenesis through activating the NF-κB pathway to induce VEGFA expression

Tumor angiogenesis is a hallmark of cancer and is involved in the tumorigenesis of solid tumors. B7-H3, an immune checkpoint molecule, plays critical roles in proliferation, metastasis and tumorigenesis in diverse tumors; however, little is known about the biological functions and molecular mechanism underlying B7-H3 in regulating colorectal cancer (CRC) angiogenesis. In this study, we first demonstrated that the expression of B7-H3 was significantly upregulated and was positively associated with platelet endothelial cell adhesion molecule-1 (CD31) level in tissue samples from patients with CRC. In addition, a series of in vitro and in vivo experiments showed that conditioned medium from B7-H3 knockdown CRC cells significantly inhibited the migration, invasion, and tube formation of human umbilical vein endothelial cells (HUVECs), whereas overexpression of B7-H3 had the opposite effect. Furthermore, B7-H3 promoted tumor angiogenesis by upregulating VEGFA expression. Recombinant VEGFA abolished the inhibitory effects of conditioned medium from shB7-H3 CRC cells on HUVEC angiogenesis, while VEGFA siRNA or a VEGFA-neutralizing antibody reversed the effects of conditioned medium from B7-H3-overexpressing CRC cells on HUVEC angiogenesis. Moreover, we verified that B7-H3 upregulated VEGFA expression and angiogenesis by activating the NF-κB pathway. Collectively, our findings identify the B7-H3/NF-κB/VEGFA axis in promoting CRC angiogenesis, which serves as a promising approach for CRC treatment.

B7-H3 is regulated by BRD4 and promotes TLR4 expression in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies worldwide. PDAC is resistant to chemotherapy and radiotherapy which leads to the poor prognosis of PDAC patients and a 5-year survival rate of less than 5%. Exploring the mechanism of the pancreatic cancer tumorigenesis is the key to finding a novel therapeutic strategy for cancer treatment. B7-H3 belongs to the B7 family of immunoregulatory proteins, and the overexpression of B7-H3 is found in various types of cancer. The regulation of B7-H3 expression in pancreatic cancer is still unclear. Here, we showed that B7-H3 acted as a negative prognostic biomarker in PDAC and promoted cell proliferation, invasion and metastasis in pancreatic cancer. Next, we applied the drug screening method to identify bromodomain and extra-terminal motif (BET) inhibitors that decreased the protein and mRNA levels of B7-H3 in pancreatic cancer cells. Moreover, we verified that BRD4 was responsible for regulating the expression of B7-H3 at the transcriptional level. Finally, our data indicated that the BRD4/B7-H3 axis modulated the expression of TLR4 in pancreatic cancer cells. Taken together, our results elucidated the regulation of B7-H3 expression in pancreatic cancer and uncovered the importance of BRD4/B7-H3/TLR4 pathway. The targeting of B7-H3 by the BET inhibitors may be a novel therapeutic strategy to overcome the immunotherapy and chemotherapy resistance in pancreatic cancer.

Immune inhibitory receptor LILRB2 is critical for the endometrial cancer progression

Although leukocyte immunoglobulin-like receptor subfamily B member 2 (LILRB2) is known as an immune inhibitory receptor to suppress the immune system, its function in cancer development remains largely unknown. Herein, we provide the first body of information showing that LILRB2 is highly expressed in the endometrial cancer. More importantly, the expression levels of LILRB2 are inversely correlated with the overall patients' survival. Knockdown of LILRB2 results in a dramatic decrease in the proliferation, colony formation and migration in several endometrial cancer cell lines in vitro. Furthermore, in vivo xenograft experiments reveal a notable reduction of tumor cell growth. Mechanistically, LILRB2 enhances the SHP2/CaMK1/CREB signaling pathways to support the expansion and migration of the endometrial cancer cells. These findings unravel an unexpected role of LILRB2 in solid cancers except for its canonical role in immune surveillance, which may serve as a potential endometrial stem cell marker and may benefit the development of novel strategies for the treatment of endometrial cancers.

Expression of ILT3 predicts poor prognosis and is inversely associated with infiltration of CD45RO+ T cells in patients with colorectal cancer

Immunoglobulin like transcript 3 (ILT3) was previously identified as an inhibitory receptor to induce T cell anergy in tranplantation, autoimmunity and allergy. Here we aimed to investigate the expression of ILT3 in colorectal cancer, analyze the association between ILT3 expression and clinicopathological variables and prognosis, and evaluate the correlation between the expression of ILT3 and CD45RO+ T cells density. Expression of ILT3 was identified on the cell membrane and/or in the cytoplasm. High expression ILT3 was identified in 55 of 85 (64.7%) tumor specimens, which was significantly higher than that in the adjacent normal tissues(5/30) (P < 0.001). High ILT3 expression was significantly associated with positive lymph node metastasis (N1-2; P = 0.03), advanced disease (stage III-IV; P = 0.03), and reduced OS in patients. The ILT3 expression level was an independent prognostic factor (P = 0.004) and inversely correlated with the number of CD45RO+ T cells (P = 0.019). In the present study, high ILT3 expression was observed in colorectal cancer and inversely associated with CD45RO+ T cells density and prognosis, suggesting that ILT3 played an important role in tumor progression by possible influence on CD45RO+ T cells in the tumor microenvironment.

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.

MicroRNA-187 inhibits tumor growth and invasion by directly targeting CD276 in colorectal cancer

Aberrantly expressed microRNAs contribute to the initiation and progression of human cancers. However, the underlying functions of microRNA-187 (miR-187) in colorectal cancer (CRC) remain largely unexplored. Here, we demonstrated that miR-187 was significantly down-regulated in CRC tissues and cell lines compared to their normal counterparts. By Kaplan-Meier analysis, we revealed that decreased miR-187 expression was closely associated with shorter overall survival and relapse-free survival of patients with CRC. By gain- and loss-of-function studies, we showed that miR-187 remarkably suppressed CRC cell proliferation, migration, invasion, and promoted cell apoptosis. Furthermore, bioinformatics analysis and luciferase reporter assay identified that CD276 was the direct functional target of miR-187 in CRC. Genetic silencing of CD276 recapitulated similar phenotype as observed in over-expression of miR-187, and restoration of CD276 completely rescued the inhibitory effect of miR-187 in CRC cells. Taken together, our study implied the essential roles of miR-187 in suppressing CRC progression, and a novel link between miR-187 and CD276 in CRC.

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.

B7-H3 as a promising target for cytotoxicity T cell in human cancer therapy

Targeting B7-H3 over-expressed tumor cells with anti-B7-H3 monoclonal antibodies inhibits tumor growth. Here we demonstrated the expression of B7 family homologue 3 (B7-H3) in a wide range of human tumor cells and further investigated whether B7-H3 could be served as a target for T-cell mediated immunotherapy against human cancers. The specific cytotoxic activity of activated T cell (ATC) armed with a novel anti-CD3 x anti-B7-H3 bispecific antibody (B7-H3Bi-Ab) against tumor cell was evaluated in vitro and in vivo. In contrast with unarmed ATC, an increase in cytotoxic activity of B7-H3Bi-armed ATC against tumor cells was observed at effector/target (E/T) ratios of 5:1, 10:1, and 20:1. Moreover, B7-H3Bi-armed ATC secreted more IFN-γ, TNF-α and IL-2 than unarmed ATC. Infusion of B7-H3Bi-armed ATC inhibited tumor growth in severe combined immunodeficiency (SCID) xenograft models, along with a significant survival benefit. Therefore, treatment with novel B7-H3Bi-armed ATC will be a promising strategy for current cancer immunotherapy.

Intratumor heterogeneity of immune checkpoints in primary renal cell cancer: Focus on HLA-G/ILT2/ILT4

The establishment and maintenance of anti-tumor immune responses are the objectives of cancer immunotherapy. Despite recent promising advances, the effectiveness of these approaches has been limited by the multiple immunosuppressive mechanisms developed by tumors (checkpoint). The aim of the present study was to demonstrate intratumor heterogeneity at the levels of immune escape strategies and tumor-host relationships. We focused on well-known checkpoints such as PD1/PDL1 and on a new checkpoint involving HLA-G and its receptors ILT2/ILT4. A prospective study was performed on 19 renal-cell carcinoma patients that were included during hospitalization for surgical tumor resection. Different areas of the tumor were collected for each patient and subjected to both immunohistochemical and flow cytometry analysis. Immune cells from peripheral blood were concomitantly analyzed for each patient. Our results show the heterogeneous expression of PD1/PDL1 and HLA-G/ILT in the various areas of the same tumor. Intratumor heterogeneity was found both at tumor cell and infiltrating immune cell levels. From a clinical point of view, this work highlights the functional redundancies of checkpoints and the need to adapt personalized poly-immunotherapy.

Allicin inhibits the invasion of lung adenocarcinoma cells by altering tissue inhibitor of metalloproteinase/matrix metalloproteinase balance via reducing the activity of phosphoinositide 3-kinase/AKT signaling

Allicin, the main active principle associated with Allium sativum chemistry, has various antitumor activities. However, to the best of our knowledge, there is no available information to address the anti-invasive effect and associated mechanism in lung adenocarcinoma. In the present study, cell viability assay, cell adhesion assay, western blot analysis, Transwell migration and invasion assays and reverse transcription-quantitative polymerase chain reaction were performed. Allicin was identified to inhibit the adhesion, invasion and migration of lung adenocarcinoma cells in a dose-dependent manner, accompanied by decreasing mRNA and protein levels of matrix metalloproteinase (MMP)-2 and MMP-9. Conversely, the mRNA and protein levels of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 were increased in a dose-dependent manner. Furthermore, it was revealed that allicin treatment significantly suppressed the phosphorylation of AKT (P<0.05), but not the total protein expression of AKT. Combined treatment with LY294002, an inhibitor of phosphoinositide 3-kinase (PI3K)/AKT signaling, and allicin led to the synergistic reduction of MMP-2 and MMP-9 expression, followed by an increase in TIMP-1 and TIMP-2 expression. The invasive capabilities of lung adenocarcinoma cells were also suppressed. However, insulin-like growth factor-1 (an activator of PI3K/AKT signaling) reversed the effects of allicin on cell invasion and expression of MMP-2, MMP-9, TIMP-1 and TIMP-2. The present study concluded that allicin may inhibit invasion of lung adenocarcinoma cells by altering TIMP/MMP balance, via reducing the activity of the PI3K/AKT signaling pathway. This indicated that allicin may be recognized as an anti-invasive agent for lung adenocarcinoma treatment.