Soluble B7-H3 promotes the invasion and metastasis of pancreatic carcinoma cells through the TLR4/NF-κB pathway

Unveiling transcriptional mechanisms of B7-H3 in breast cancer stem cells through proteomic approaches

B7-H3, an immune checkpoint molecule, is prominently overexpressed in various solid tumors, correlating with poor clinical outcomes. Despite its critical role in promoting tumorigenesis, metastasis, and immune evasion, the regulatory mechanisms governing B7-H3 expression, particularly in cancer stem cells (CSCs), remain elusive. In this comprehensive study, we focused on breast CSCs to uncover the transcriptional regulators driving B7-H3 overexpression. Utilizing DNA affinity purification-mass spectrometry (DAP-MS) to analyze B7-H3 promoter regions, we identified a novel set of transcription factors, including DDB1, XRCC5, PARP1, RPA1, and RPA3, as key modulators of B7-H3 expression. Functional assays revealed that targeting DDB1 with nitazoxanide significantly downregulated B7-H3 expression, subsequently impairing tumor sphere formation and cell migration in breast CSCs. These findings not only elucidate the complex transcriptional network controlling B7-H3 expression but also open new avenues for developing targeted immunotherapies aimed at disrupting CSC-driven cancer progression.

B7H3 in Gastrointestinal Tumors: Role in Immune Modulation and Cancer Progression: A Review of the Literature

B7-H3 (CD276), a member of the B7 immune checkpoint family, plays a critical role in modulating immune responses and has emerged as a promising target in cancer therapy. It is highly expressed in various malignancies, where it promotes tumor evasion from T cell surveillance and contributes to cancer progression, metastasis, and therapeutic resistance, showing a correlation with the poor prognosis of patients. Although its receptors were not fully identified, B7-H3 signaling involves key intracellular pathways, including JAK/STAT, NF-κB, PI3K/Akt, and MAPK, driving processes crucial for supporting tumor growth such as cell proliferation, invasion, and apoptosis inhibition. Beyond immune modulation, B7-H3 influences cancer cell metabolism, angiogenesis, and epithelial-to-mesenchymal transition, further exacerbating tumor aggressiveness. The development of B7-H3-targeting therapies, including monoclonal antibodies, antibody-drug conjugates, and CAR-T cells, offers promising avenues for treatment. This review provides an up-to-date summary of the B7H3 mechanisms of action, putative receptors, and ongoing clinical trials evaluating therapies targeting B7H3, focusing on the molecule's role in gastrointestinal tumors.

Impact of Radiometal Chelates on In Vivo Visualization of Immune Checkpoint Protein Using Radiolabeled Affibody Molecules

The immune checkpoint protein B7-H3 (CD276) is overexpressed in various cancers and is an attractive target for the treatment of malignant tumors. Radionuclide molecular imaging of B7-H3 expression using engineered scaffold proteins such as Affibody molecules is a promising strategy for the selection of potential responders to B7-H3-targeted therapy. Feasibility of B7-H3 imaging was demonstrated using two 99mTc-labeled probes, AC12 and an affinity-matured SYNT179 using a [99mTc]Tc-GGGC label. This study aimed to evaluate whether the use of a residualizing 111In-based label provides better imaging contrast compared with a nonresidualizing label. To do that, SYNT179 and AC12-GGGC Affibody molecules were labeled with 111In using (4,10-bis-carboxymethyl-7-{[2-(2,5-dioxo-3-thioxo-pyrrolidin-1-yl)-ethylcarbamoyl]-methyl}-1,4,7,10-tetraaza-cyclododec-1-yl)-acetic acid (maleimide-DOTA) chelator, site-specifically coupled to the C-terminus of Affibody molecules. The binding affinities of the 111In-labeled conjugates to B7-H3-expressing living cells were higher compared with the affinities of the 99mTc-labeled variants. In mice with B7-H3-expressing xenografts, the tumor uptake of 111In-labeled proteins (3.6 ± 0.3 and 1.8 ± 0.5%ID/g for [111In]In-SYNT179-DOTA and [111In]In-AC12-DOTA, respectively) was significantly (p < 0.05, ANOVA) higher than those for 99mTc-labeled counterparts (1.6 ± 0.2%ID/g and 0.8 ± 0.2%ID/g for [99mTc]Tc-SYNT179 and [99mTc]Tc-AC12-GGGC, respectively). The best variant, [111In]In-SYNT179-DOTA, provided a tumor-to-blood ratio of 31.1 ± 2.9, which was twice higher than that for [99mTc]Tc-SYNT179 and 7-fold higher than that for [99mTc]Tc-AC12-GGGC. Both 111In-labeled Affibody molecules had higher renal retention compared with 99mTc-labeled ones, but the hepatobiliary excretion of 111In-labeled proteins was appreciably lower, potentially improving the imaging of abdominal metastases. Overall, [111In]In-SYNT179-DOTA is the most promising tracer for visualization of B7-H3 expression.

Soluble B7 and TNF family in colorectal cancer: Serum level, prognostic and treatment value

Soluble immune checkpoints (sIC) are crucial factors in the immune system. They regulate immune responses by transforming intercellular signals via binding to their membrane-bound receptor or ligand. Moreover, soluble ICs are vital in immune regulation, cancer development, and prognosis. They can be identified and measured in various tumor microenvironments. Recently, sICs have become increasingly important in clinically assessing malignancies like colorectal cancer (CRC) patients. This review explores the evolving role of the soluble B7 family and soluble tumor necrosis factor (TNF) superfamily members in predicting disease progression, treatment response, and overall patient outcomes in CRC. We comprehensively analyze the diagnostic and prognostic potential of soluble immune checkpoints in CRC. Understanding the role of these soluble immune checkpoints in CRC management and their potential as targets for precision medicine approaches can be critical for improving outcomes for patients with colorectal cancer.

Predictive value of plasma sB7-H3 and YKL-40 in pediatric refractory Mycoplasma pneumoniae pneumonia

Objective

This study investigated the clinical significance of plasma sB7-H3 and YKL-40 levels in children with refractory Mycoplasma pneumoniae pneumonia (RMPP).

Methods

A total of 182 RMPP patients (103 general Mycoplasma pneumoniae patients and 79 RMPP patients) were included. sB7-H3, YKL-40, and other inflammatory factors were measured. Independent factors associated with the early diagnosis of RMPP were determined. The value of each independent risk factor in predicting RMPP was evaluated.

Results

The RMPP group reported significantly longer hospital stays and total fever durations. Levels of C-reactive protein, D-dimer, IL-13, IL-6/-10, sB7-H3, and YKL-40 were higher in the RMPP group. sB7-H3 was positively correlated with IL-13, IL-6, and IL-4, whereas YKL-40 was positively correlated with all of the above indicators (IL-5 was also included). sB7-H3 and YKL-40 were independent risk factors for RMPP. The critical values for sB7-H3 and YKL-40 were 3.525 and 313.3 ng/mL, respectively. sB7-H3 and YKL-40 had areas under the curve of 0.734 and 0.859, respectively. YKL-40 had high sensitivity and specificity of 88.61 and 87.38%, respectively. Both indicators had predictive value, YKL-40 had the highest predictive ability for RMPP.

Conclusion

Detection of sB7-H3 and YKL-40 levels in the plasma may be useful in diagnosing RMPP early in the disease process.

IDH mutation, glioma immunogenicity, and therapeutic challenge of primary mismatch repair deficient IDH-mutant astrocytoma PMMRDIA: a systematic review

In 2021, Suwala et al. described Primary Mismatch Repair Deficient IDH-mutant Astrocytoma (PMMRDIA) as a distinct group of gliomas. In unsupervised clustering, PMMRDIA forms distinct cluster, separate from other IDH-mutant gliomas, including IDH-mutant gliomas with secondary mismatch repair (MMR) deficiency. In the published cohort, three patients received treatment with an immune checkpoint blocker (ICB), yet none exhibited a response, which aligns with existing knowledge about the decreased immunogenicity of IDH-mutant gliomas in comparison to IDH-wildtype. In the case of PMMRDIA, the inherent resistance to the standard-of-care temozolomide caused by MMR deficiency is an additional challenge. It is known that a gain-of-function mutation of IDH1/2 genes produces the oncometabolite R-2-hydroxyglutarate (R-2-HG), which increases DNA and histone methylation contributing to the characteristic glioma-associated CpG island methylator phenotype (G-CIMP). While other factors could be involved in remodeling the tumor microenvironment (TME) of IDH-mutant gliomas, this systematic review emphasizes the role of R-2-HG and the subsequent G-CIMP in immune suppression. This highlights a potential actionable pathway to enhance the response of ICB, which might be relevant for addressing the unmet therapeutic challenge of PMMRDIA.

B7-H3 in glioblastoma and beyond: significance and therapeutic strategies

Cancer has emerged as the second most prevalent disease and the leading cause of death, claiming the lives of 10 million individuals each year. The predominant varieties of cancer encompass breast, lung, colon, rectal, and prostate cancers. Among the more aggressive malignancies is glioblastoma, categorized as WHO stage 4 brain cancer. Following diagnosis, the typical life expectancy ranges from 12 to 15 months, as current established treatments like surgical intervention, radiotherapy, and chemotherapy using temozolomide exhibit limited effectiveness. Beyond conventional approaches, the exploration of immunotherapy for glioblastoma treatment is underway. A methodology involves CAR-T cells, monoclonal antibodies, ADCC and nanobodies sourced from camelids. Immunotherapy's recent focal point is the cellular ligand B7-H3, notably abundant in tumor cells while either scarce or absent in normal ones. Its expression elevates with cancer progression and serves as a promising prognostic marker. In this article, we delve into the essence of B7-H3, elucidating its function and involvement in signaling pathways. We delineate the receptors it binds to and its significance in glioblastoma and other cancer types. Lastly, we examine its role in immunotherapy and the utilization of nanobodies in this domain.

Antibody-drug conjugates for hepato-pancreato-biliary malignancies: "Magic bullets" to the rescue?

Hepato-Pancreato-Biliary (HPB) malignancies constitute a highly aggressive group of cancers that have a dismal prognosis. Patients not amenable to curative intent surgical resection are managed with systemic chemotherapy which, however, confers little survival benefit. Antibody-Drug Conjugates (ADCs) are tripartite compounds that merge the intricate selectivity and specificity of monoclonal antibodies with the cytodestructive potency of attached supertoxic payloads. In view of the unmet need for drugs that will enhance the survival rates of HPB cancer patients, the assessment of ADCs for treating HPB malignancies has become the focus of extensive clinical and preclinical investigation, showing encouraging preliminary results. In the current review, we offer a comprehensive overview of the growing body of evidence on ADC approaches tested for HPB malignancies. Starting from a concise discussion of the functional principles of ADCs, we summarize here all available data from preclinical and clinical studies evaluating ADCs in HPB cancers.

B7 homolog 3 in pancreatic cancer

Despite advances in cancer treatment, pancreatic cancer (PC) remains a disease with high mortality rates and poor survival outcomes. The B7 homolog 3 (B7-H3) checkpoint molecule is overexpressed among many malignant tumors, including PC, with low or absent expression in healthy tissues. By modulating various immunological and nonimmunological molecular mechanisms, B7-H3 may influence the progression of PC. However, the impact of B7-H3 on the survival of patients with PC remains a subject of debate. Still, most available scientific data recognize this molecule as a suppressive factor to antitumor immunity in PC. Furthermore, it has been demonstrated that B7-H3 stimulates the migration, invasion, and metastasis of PC cells, and enhances resistance to chemotherapy. In preclinical models of PC, B7-H3-targeting monoclonal antibodies have exerted profound antitumor effects by increasing natural killer cell-mediated antibody-dependent cellular cytotoxicity and delivering radioisotopes and cytotoxic drugs to the tumor site. Finally, PC treatment with B7-H3-targeting antibody-drug conjugates and chimeric antigen receptor T cells is being tested in clinical studies. This review provides a comprehensive analysis of all PC-related studies in the context of B7-H3 and points to deficiencies in the current data that should be overcome by future research.

Recent developments in immunotherapy for gastrointestinal tract cancers

The past few decades have witnessed the rise of immunotherapy for Gastrointestinal (GI) tract cancers. The role of immune checkpoint inhibitors (ICIs), particularly programmed death protein 1 (PD-1) and PD ligand-1 antibodies, has become increasingly pivotal in the treatment of advanced and perioperative GI tract cancers. Currently, anti-PD-1 plus chemotherapy is considered as first-line regimen for unselected advanced gastric/gastroesophageal junction adenocarcinoma (G/GEJC), mismatch repair deficient (dMMR)/microsatellite instability-high (MSI-H) colorectal cancer (CRC), and advanced esophageal cancer (EC). In addition, the encouraging performance of claudin18.2-redirected chimeric antigen receptor T-cell (CAR-T) therapy in later-line GI tract cancers brings new hope for cell therapy in solid tumour treatment. Nevertheless, immunotherapy for GI tumour remains yet precise, and researchers are dedicated to further maximising and optimising the efficacy. This review summarises the important research, latest progress, and future directions of immunotherapy for GI tract cancers including EC, G/GEJC, and CRC.

CD276 Promotes an Inhibitory Tumor Microenvironment in Hepatocellular Carcinoma and is Associated with Poor Prognosis

Background

CD276 is an emerging immune checkpoint molecule that has been implicated in various cancers. However, its specific role in hepatocellular carcinoma (HCC) remains unclear. This study examined the impact of CD276 on patient prognosis and the tumor microenvironment (TME).

Methods

The Cancer Genome Atlas (TCGA) database was utilized to evaluate CD276 expression in HCC and the association between CD276 and immune indicators was also analyzed. The signaling pathways correlated with CD276 expression were identified by gene set enrichment analysis (GSEA). Different algorithms were used to assess immune cell infiltration. The effect of CD276 knockdown on HCC cell phenotypes and its relationship with macrophage polarization was examined using the cell counting kit 8 (CCK-8) assay and co-culture system.

Results

CD276 was upregulated in HCC and associated with unfavorable clinical outcomes. Hgh CD276 expression was associated with enrichment of the G2/M checkpoint, E2F targets, and mitotic spindles. CD276 expression was correlated with the infiltration of immune cells, including high level of tumor-associated macrophages and low levels of CD8+ T cells. Knockdown of CD276 decreased HCC cell proliferation and increased apoptosis. CD276 silencing in HCC cells and co-culture with THP-1-derived macrophages had a regulatory effect on macrophage polarization and macrophage-mediated cell proliferation and migration.

Conclusion

CD276 expression in HCC is associated with unfavorable clinical outcomes and may contribute to the development of an immunosuppressive microenvironment. Specifically, CD276 was associated with alterations in immune cell infiltration, immune marker expression, and macrophage polarization during HCC progression, suggesting its potential as a prognostic indicator and promising target for immunotherapeutic intervention in HCC.

Identification of a urinary CD276 fragment for detecting resectable pancreatic cancer using a C-terminal proteomics strategy

This study aimed to confirm urinary protein fragments in relation to the presence of pancreatic ductal adenocarcinoma (PDAC) via a C-terminal proteomics strategy using exploratory and validation cohorts. Urinary fragments were examined by iTRAQ-labelling of tryptic peptides and concentrations of C-terminal fragments were evaluated. Only the urinary CD276 fragment showed a fold change (FC) of > 1.5 with a significant difference of P < 0.01 between healthy (H) and PDAC participants in both the exploratory (H, n = 42; PDAC, n = 39) and validation cohorts (H, n = 36; resectable PDAC, n = 28). The sensitivity and specificity of the CD276 fragment for diagnosing resectable PDAC were 75% and 89%, respectively, in the validation cohort. Postoperative urinary levels of the CD276 fragment were low as compared to those before surgery (n = 18, P < 0.01). Comprehensive C-terminus proteomics identified an increase in the urinary CD276 fragment level as a feature of patients with PDAC. The urinary CD276 fragment is a potential biomarker for detecting resectable PDAC.

Soluble immune checkpoints: implications for cancer prognosis and response to immune checkpoint therapy and conventional therapies

Longitudinal sampling of tumor tissue from patients with solid cancers, aside from melanoma and a few other cases, is often unfeasible, and thus may not capture the plasticity of interactions between the tumor and immune system under selective pressure of a given therapy. Peripheral blood analyses provide salient information about the human peripheral immunome while offering technical and practical advantages over traditional tumor biopsies, and should be utilized where possible alongside interrogation of the tumor. Some common blood-based biomarkers used to study the immune response include immune cell subsets, circulating tumor DNA, and protein analytes such as cytokines. With the recent explosion of immune checkpoint inhibitors (ICI) as a modality of treatment in multiple cancer types, soluble immune checkpoints have become a relevant area of investigation for peripheral immune-based biomarkers. However, the exact functions of soluble immune checkpoints and their roles in cancer for the most part remain unclear. This review discusses current literature on the production, function, and expression of nine soluble immune checkpoints - sPD-L1, sPD-1, sCTLA4, sCD80, sTIM3, sLAG3, sB7-H3, sBTLA, and sHVEM - in patients with solid tumors, and explores their role as biomarkers of response to ICI as well as to conventional therapies (chemotherapy, radiotherapy, targeted therapy, and surgery) in cancer patients.

B7-H3 suppresses CD8+ T cell immunologic function through reprogramming glycolytic metabolism

Malignant neoplasms pose a formidable threat to human well-being. Prior studies have documented the extensive expression of B7 homolog 3 (B7-H3 or CD276) across various tumors, affecting glucose metabolism. Yet, the link between metabolic modulation and immune responses remains largely unexplored. Our study reveals a significant association between B7-H3 expression and advanced tumor stages, lymph node metastasis, and tumor location in oral squamous cell carcinoma (OSCC). We further elucidate B7-H3's role in mediating glucose competition between cancer cells and CD8+ T cells. Through co-culturing tumor cells with flow cytometry-sorted CD8+ T cells, we measured glucose uptake and lactate secretion in both cell types. Additionally, we assessed interferon-gamma (IFN-γ) release and the immune and exhaustion status of CD8+ T cells. Our findings indicate that B7-H3 enhances glycolysis in OSCC and malignant melanoma, while simultaneously inhibiting CD8+ T cell glycolysis. Silencing B7-H3 led to increased IFN-γ secretion in co-cultures, highlighting its significant role in modulating CD8+ T cell functions within the tumor microenvironment and its impact on tumorigenicity. We also demonstrate that glycolysis inhibition can be mitigated by exogenous glucose supplementation. Mechanistically, our study suggests B7-H3's influence on metabolism might be mediated through the phosphoinositide3-kinase (PI3K)/ protein kinase B (Akt)/ mammalian target of rapamycin (mTOR) signaling pathway. This research unveils how B7-H3 affects immune functions via metabolic reprogramming.

B7-H3 at the crossroads between tumor plasticity and colorectal cancer progression: a potential target for therapeutic intervention

B7-H3 (B7 homology 3 protein) is an important transmembrane immunoregulatory protein expressed in immune cells, antigen-presenting cells, and tumor cells. Studies reveal a multifaceted role of B7-H3 in tumor progression by modulating various cancer hallmarks involving angiogenesis, immune evasion, and tumor microenvironment, and it is also a promising candidate for cancer immunotherapy. In colorectal cancer (CRC), B7-H3 has been associated with various aspects of disease progression, such as evasion of tumor immune surveillance, tumor-node metastasis, and poor prognosis. Strategies to block or interfere with B7-H3 in its immunological and non-immunological functions are under investigation. In this study, we explore the role of B7-H3 in tumor plasticity, emphasizing tumor glucose metabolism, angiogenesis, epithelial-mesenchymal transition, cancer stem cells, apoptosis, and changing immune signatures in the tumor immune landscape. We discuss how B7-H3-induced tumor plasticity contributes to immune evasion, metastasis, and therapy resistance. Furthermore, we delve into the most recent advancements in targeting B7-H3-based tumor immunotherapy as a potential approach to CRC treatment.

A promising target for breast cancer: B7-H3

Breast cancer (BC) is the second-leading factor of mortality for women globally and is brought on by a variety of genetic and environmental causes. The conventional treatments for this disease have limitations, making it difficult to improve the lifespan of breast cancer patients. As a result, extensive research has been conducted over the past decade to find innovative solutions to these challenges. Targeting of the antitumor immune response through the immunomodulatory checkpoint protein B7 family has revolutionized cancer treatment and led to intermittent patient responses. B7-H3 has recently received attention because of its significant demodulation and its immunomodulatory effects in many cancers. Uncontrolled B7-H3 expression and a bad outlook are strongly associated, according to a substantial body of cancer research. Numerous studies have shown that BC has significant B7-H3 expression, and B7-H3 induces an immune evasion phenotype, consequently enhancing the survival, proliferation, metastasis, and drug resistance of BC cells. Thus, an innovative target for immunotherapy against BC may be the B7-H3 checkpoint.In this review, we discuss the structure and regulation of B7-H3 and its double costimulatory/coinhibitory function within the framework of cancer and normal physiology. Then we expound the malignant behavior of B7-H3 in BC and its role in the tumor microenvironment (TME) and finally focus on targeted drugs against B7-H3 that have opened new therapeutic opportunities in BC.

B7-H3 Inhibitors in Oncology Clinical Trials: A Review

B7-H3 is a transmembrane receptor highly prevalent on malignant cells and plays an important role in adaptive immunity that is not fully elucidated. Targeted B7-H3 inhibitors, including antibody-drug conjugates, radioimmunotherapy, and monoclonal antibodies, are a new class of antineoplastic agents showing promising preliminary clinical efficacy, observed with several of these agents against multiple tumor types. Particularly promising treatments are enoblituzumab for prostate cancer, 131I-omburtamab for central nervous system malignancies, and HS-20093 for small-cell lung cancer but further studies are warranted. There are clinical trials on the horizon that have not yet enrolled patients examining chimeric antigen receptor T-cell therapies, bi- and tri-specific killer engagers, and dual-affinity retargeting proteins. These data will be telling of the efficacy of B7-H3 inhibitors in both hematologic and solid malignancies. This study aimed to compile available results of B7-H3 inhibitors in oncology clinical trials.

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.

Current status and future challenges of CAR-T cell therapy for osteosarcoma

Osteosarcoma, the most common bone malignancy in children and adolescents, poses considerable challenges in terms of prognosis, especially for patients with metastatic or recurrent disease. While surgical intervention and adjuvant chemotherapy have improved survival rates, limitations such as impractical tumor removal or chemotherapy resistance hinder the treatment outcomes. Chimeric antigen receptor (CAR)-T cell therapy, an innovative immunotherapy approach that involves targeting tumor antigens and releasing immune factors, has shown significant advancements in the treatment of hematological malignancies. However, its application in solid tumors, including osteosarcoma, is constrained by factors such as low antigen specificity, limited persistence, and the complex tumor microenvironment. Research on osteosarcoma is ongoing, and some targets have shown promising results in pre-clinical studies. This review summarizes the current status of research on CAR-T cell therapy for osteosarcoma by compiling recent literature. It also proposes future research directions to enhance the treatment of osteosarcoma.

CD276 as a Candidate Target for Immunotherapy in Medullary Thyroid Cancer

Medullary thyroid cancer (MTC) is a rare malignancy, and the treatment of metastatic MTC is challenging. In previous work, immune profiling (RNA-Seq) of MTC identified CD276 as a potential target for immunotherapy. CD276 expression was 3-fold higher in MTC cells than in normal tissues. Paraffin blocks from patients with MTC were analyzed by immunohistochemistry to confirm the results of RNA-Seq. Serial sections were incubated with anti-CD276 antibody, and scored according to staining intensity and the percentage of immunoreactive cells. The results showed that CD276 expression was higher in MTC tissues than in controls. A lower percentage of immunoreactive cells correlated with the absence of lateral node metastasis, lower levels of calcitonin after surgery, no additional treatments, and remission. There were statistically significant associations of intensity of immunostaining and percentage of CD276 immunoreactive cells with clinical factors and the course of the disease. These results suggest that targeting this immune checkpoint molecule CD276 could be a promising strategy for the treatment of MTC.

Toll-Like Receptors and the Response to Radiotherapy in Solid Tumors: Challenges and Opportunities

Toll-like receptors (TLRs) are indispensable for the activation, maintenance and halting of immune responses. TLRs can mediate inflammation by recognizing molecular patterns in microbes (pathogen-associated molecular patterns: PAMPs) and endogenous ligands (danger-associated molecular patterns: DAMPs) released by injured or dead cells. For this reason, TLR ligands have attracted much attention in recent years in many cancer vaccines, alone or in combination with immunotherapy, chemotherapy and radiotherapy (RT). TLRs have been shown to play controversial roles in cancer, depending on various factors that can mediate tumor progression or apoptosis. Several TLR agonists have reached clinical trials and are being evaluated in combination with standard of care therapies, including RT. Despite their prolific and central role in mediating immune responses, the role of TLRs in cancer, particularly in response to radiation, remains poorly understood. Radiation is recognized as either a direct stimulant of TLR pathways, or indirectly through the damage it causes to target cells that subsequently activate TLRs. These effects can mediate pro-tumoral and anti-tumoral effects depending on various factors such as radiation dose and fractionation, as well as host genomic features. In this review, we examine how TLR signaling affects tumor response to RT, and we provide a framework for the design of TLR-based therapies with RT.

An optimized IgG-based B7-H3xCD3 bispecific antibody for treatment of gastrointestinal cancers

T cell-based immunotherapy has revolutionized oncological treatment. However, many patients do not respond to treatment, and long-term remissions remain rare, particularly in gastrointestinal cancers like colorectal cancer (CRC). B7-H3 is overexpressed in multiple cancer entities including CRC on both tumor cells and tumor vasculature, the latter facilitating influx of effector cells into the tumor site upon therapeutic targeting. We generated a panel of T cell-recruiting B7-H3xCD3 bispecific antibodies (bsAbs) and show that targeting a membrane-proximal B7-H3 epitope allows for a 100-fold reduction of CD3 affinity. In vitro, our lead compound CC-3 showed superior tumor cell killing, T cell activation, proliferation, and memory formation, whereas undesired cytokine release was reduced. In vivo, CC-3 mediated potent antitumor activity in three independent models using immunocompromised mice adoptively transferred with human effector cells with regard to prevention of lung metastasis and flank tumor growth as well as elimination of large established tumors. Thus, fine-tuning of both target and CD3 affinities as well as binding epitopes allowed for the generation of a B7-H3xCD3 bsAbs with promising therapeutic activity. CC-3 is presently undergoing good manufacturing practice (GMP) production to enable evaluation in a clinical "first-in-human" study in CRC.

Long Non-Coding RNAs as Epigenetic Regulators of Immune Checkpoints in Cancer Immunity

In recent years, cancer treatment has undergone significant changes, predominantly in the shift towards immunotherapeutic strategies using immune checkpoint inhibitors. Despite the clinical efficacy of many of these inhibitors, the overall response rate remains modest, and immunotherapies for many cancers have proved ineffective, highlighting the importance of knowing the tumor microenvironment and heterogeneity of each malignancy in patients. Long non-coding RNAs (lncRNAs) have attracted increasing attention for their ability to control various biological processes by targeting different molecular pathways. Some lncRNAs have a regulatory role in immune checkpoints, suggesting they might be utilized as a target for immune checkpoint treatment. The focus of this review is to describe relevant lncRNAs and their targets and functions to understand key regulatory mechanisms that may contribute in regulating immune checkpoints. We also provide the state of the art on super-enhancers lncRNAs (selncRNAs) and circular RNAs (circRNAs), which have recently been reported as modulators of immune checkpoint molecules within the framework of human cancer. Other feasible mechanisms of interaction between lncRNAs and immune checkpoints are also reported, along with the use of miRNAs and circRNAs, in generating new tumor immune microenvironments, which can further help avoid tumor evasion.

B7-H3: A Useful Emerging Diagnostic Marker for Colon Cancer

Background

Colon cancer is the second most common malignancy causing the majority of cancer-related deaths. B7-H3 concentrations have drawn major interest as possible diagnostic biomarkers of cancer. The aim of this study was to measure the preoperative serum B7-H3 levels and to determine those that are replaced in colon cancer.

Method

We measured preoperative serum B7-H3 concentrations of 90 patients aged 57-69 years diagnosed with colon cancer and 50 age-matched healthy individuals. B7-H3 levels were determined using the sandwich enzyme-linked immunosorbent assay (ELISA). Patients were categorized by stage based on the TNM staging system, and the serum levels of B7-H3 were compared between patients with different TNM stages.

Result

No statistically significant difference was found between the patient and control groups in terms of age and gender. Preoperative serum B7-H3 levels were statistically significantly higher in patients with colon cancer than in the healthy group (p < 0.001). Preoperative serum B7-H3 concentration of the stage IV patients was significantly higher than those of the patients with stage I and stage II disease. In addition, higher serum B7-H3 levels were associated with lymph node status and distant metastasis in colon cancer.

Conclusion

We showed that B7-H3 is highly expressed in colon cancer and can be used as a candidate diagnostic biomarker and a potential target in colon cancer in future.

B7 Family Members in Pancreatic Ductal Adenocarcinoma: Attractive Targets for Cancer Immunotherapy

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers, with a five-year survival rate of approximately 5-10%. The immune checkpoint blockade represented by PD-1/PD-L1 inhibitors has been effective in a variety of solid tumors but has had little clinical response in pancreatic cancer patients. The unique suppressive immune microenvironment is the primary reason for this outcome, and it is essential to identify key targets to remodel the immune microenvironment. Some B7 family immune checkpoints, particularly PD-L1, PD-L2, B7-H3, B7-H4, VISTA and HHLA2, have been identified as playing a significant role in the control of tumor immune responses. This paper provides a comprehensive overview of the recent research progress of some members of the B7 family in pancreatic cancer, which revealed that they can be involved in tumor progression through immune-dependent and non-immune-dependent pathways, highlighting the mechanisms of their involvement in tumor immune escape and assessing the prospects of their clinical application. Targeting B7 family immune checkpoints is expected to result in novel immunotherapeutic treatments for patients with pancreatic cancer.

Tumor buster - where will the CAR-T cell therapy 'missile' go?

Chimeric antigen receptor (CAR) T cell (CAR-T cell) therapy based on gene editing technology represents a significant breakthrough in personalized immunotherapy for human cancer. This strategy uses genetic modification to enable T cells to target tumor-specific antigens, attack specific cancer cells, and bypass tumor cell apoptosis avoidance mechanisms to some extent. This method has been extensively used to treat hematologic diseases, but the therapeutic effect in solid tumors is not ideal. Tumor antigen escape, treatment-related toxicity, and the immunosuppressive tumor microenvironment (TME) limit their use of it. Target selection is the most critical aspect in determining the prognosis of patients receiving this treatment. This review provides a comprehensive summary of all therapeutic targets used in the clinic or shown promising potential. We summarize CAR-T cell therapies' clinical trials, applications, research frontiers, and limitations in treating different cancers. We also explore coping strategies when encountering sub-optimal tumor-associated antigens (TAA) or TAA loss. Moreover, the importance of CAR-T cell therapy in cancer immunotherapy is emphasized.

Integrated analysis of cervical squamous cell carcinoma cohorts from three continents reveals conserved subtypes of prognostic significance

Human papillomavirus (HPV)-associated cervical cancer is a leading cause of cancer deaths in women. Here we present an integrated multi-omic analysis of 643 cervical squamous cell carcinomas (CSCC, the most common histological variant of cervical cancer), representing patient populations from the USA, Europe and Sub-Saharan Africa and identify two CSCC subtypes (C1 and C2) with differing prognosis. C1 and C2 tumours can be driven by either of the two most common HPV types in cervical cancer (16 and 18) and while HPV16 and HPV18 are overrepresented among C1 and C2 tumours respectively, the prognostic difference between groups is not due to HPV type. C2 tumours, which comprise approximately 20% of CSCCs across these cohorts, display distinct genomic alterations, including loss or mutation of the STK11 tumour suppressor gene, increased expression of several immune checkpoint genes and differences in the tumour immune microenvironment that may explain the shorter survival associated with this group. In conclusion, we identify two therapy-relevant CSCC subtypes that share the same defining characteristics across three geographically diverse cohorts.

Human papillomavirus (HPV) is a known cause of cervical cancer. Here, the authors perform a multi-omic analysis using published cervical squamous cell carcinoma cohorts from the USA, Europe, and SubSaharan Africa and identify two cervical squamous cell carcinoma subtypes that display prognostic differences.

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.

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.

Immune checkpoint molecules in neuroblastoma: A clinical perspective

High-risk neuroblastoma (NB) is challenging to treat with 5-year long-term survival in patients remaining below 50% and low chances of survival after tumor relapse or recurrence. Different strategies are being tested or under evaluation to destroy resistant tumors and improve survival outcomes in NB patients. Immunotherapy, which uses certain parts of a person's immune system to recognize or kill tumor cells, effectively improves patient outcomes in several types of cancer, including NB. One of the immunotherapy strategies is to block immune checkpoint signaling in tumors to increase tumor immunogenicity and anti-tumor immunity. Immune checkpoint proteins put brakes on immune cell functions to regulate immune activation, but this activity is exploited in tumors to evade immune surveillance and attack. Immune checkpoint proteins play an essential role in NB biology and immune escape mechanisms, which makes these tumors immunologically cold. Therapeutic strategies to block immune checkpoint signaling have shown promising outcomes in NB but only in a subset of patients. However, combining immune checkpoint blockade with other therapies, including conjugated antibody-based immunotherapy, radioimmunotherapy, tumor vaccines, or cellular therapies like modified T or natural killer (NK) cells, has shown encouraging results in enhancing anti-tumor immunity in the preclinical setting. An analysis of publicly available dataset using computational tools has unraveled the complexity of multiple cancer including NB. This review comprehensively summarizes the current information on immune checkpoint molecules, their biology, role in immune suppression and tumor development, and novel therapeutic approaches combining immune checkpoint inhibitors with other therapies to combat high-risk NB.

Impact of radiotherapy on the immune landscape in oesophageal adenocarcinoma

BACKGROUND

In the contemporary era of cancer immunotherapy, an abundance of clinical and translational studies have reported radiotherapy (RT) and immunotherapies as a viable option for immunomodulation of many cancer subtypes, with many related clinical trials ongoing. In locally advanced disease, chemotherapy or chemoradiotherapy followed by surgical excision of the tumour remain the principal treatment strategy in oesophageal adenocarcinoma (OAC), however, the use of the host immune system to improve anti-tumour immunity is rapidly garnering increased support in the curative setting.

AIM

To immunophenotype OAC patients' immune checkpoint (IC) expression with and without radiation and evaluate the effects of checkpoint blockade on cell viability.

METHODS

In the contemporary era of cancer immunotherapy, an abundance of studies have demonstrated that combination RT and IC inhibitors (ICIs) are effective in the immunomodulation of many cancer subtypes, with many related clinical trials ongoing. Although surgical excision and elimination of tumour cells by chemotherapy or chemoradiotherapy remains the gold standard approach in OAC, the propagation of anti-tumour immune responses is rapidly garnering increased support in the curative setting. The aim of this body of work was to immunophenotype OAC patients' IC expression with and without radiation and to establish the impact of checkpoint blockade on cell viability. This study was a hybrid combination of in vitro and ex vivo models. Quantification of serum immune proteins was performed by enzyme-linked immunosorbent assay. Flow cytometry staining was performed to evaluate IC expression for in vitro OAC cell lines and ex vivo OAC biopsies. Cell viability in the presence of radiation with and without IC blockade was assessed by a cell counting kit-8 assay.

RESULTS

We identified that conventional dosing and hypofractionated approaches resulted in increased IC expression (PD-1, PD-L1, TIM3, TIGIT) in vitro and ex vivo in OAC. There were two distinct subcohorts with one demonstrating significant upregulation of ICs and the contrary in the other cohort. Increasing IC expression post RT was associated with a more aggressive tumour phenotype and adverse features of tumour biology. The use of anti-PD-1 and anti-PD-L1 immunotherapies in combination with radiation resulted in a significant and synergistic reduction in viability of both radiosensitive and radioresistant OAC cells in vitro. Interleukin-21 (IL-21) and IL-31 significantly increased, with a concomitant reduction in IL-23 as a consequence of 4 Gray radiation. Similarly, radiation induced an anti-angiogenic tumour milieu with reduced expression of vascular endothelial growth factor-A, basic fibroblast growth factor, Flt-1 and placental growth factor.

CONCLUSION

The findings of the current study demonstrate synergistic potential for the use of ICIs and ionising radiation to potentiate established anti-tumour responses in the neoadjuvant setting and is of particular interest in those with advanced disease, adverse features of tumour biology and poor treatment responses to conventional therapies.

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.

Biological Characteristics and Clinical Significance of Soluble PD-1/PD-L1 and Exosomal PD-L1 in Cancer

The immune checkpoint pathway consisting of the cell membrane-bound molecule programmed death protein 1 (PD-1) and its ligand PD-L1 has been found to mediate negative regulatory signals that effectively inhibit T-cell proliferation and function and impair antitumor immune responses. Considerable evidence suggests that the PD-1/PD-L1 pathway is responsible for tumor immune tolerance and immune escape. Blockage of this pathway has been found to reverse T lymphocyte depletion and restore antitumor immunity. Antagonists targeting this pathway have shown significant clinical activity in specific cancer types. Although originally identified as membrane-type molecules, several other forms of PD-1/PD-L1 have been detected in the blood of cancer patients, including soluble PD-1/PD-L1 (sPD-1/sPD-L1) and exosomal PD-L1 (exoPD-L1), increasing the composition and functional complications of the PD-1/PD-L1 signaling pathway. For example, sPD-1 has been shown to block the PD-1/PD-L immunosuppressive pathway by binding to PD-L1 and PD-L2, whereas the role of sPD-L1 and its mechanism of action in cancer remain unclear. In addition, many studies have investigated the roles of exoPD-L1 in immunosuppression, as a biomarker for tumor progression and as a predictive biomarker for response to immunotherapy. This review describes the molecular mechanisms underlying the generation of sPD-1/sPD-L1 and exoPD-L1, along with their biological activities and methods of detection. In addition, this review discusses the clinical importance of sPD-1/sPD-L1 and exoPD-L1 in cancer, including their predictive and prognostic roles and the effects of treatments that target these molecules.

GOLM1 as a Potential Therapeutic Target Modulates B7-H3 Secretion to Drive Ovarian Cancer Metastasis

Introduction

This study was aimed at exploring whether the Golgi membrane protein 1 (GOLM1) enhanced ovarian cancer metastasis through B7-H3-dependent way.

Methods

We collected the ovarian cancer patient samples from available databases including GEPIA, starBase, and Protein Altas that have GOLM1 and B7-H3 mRNA and protein expression. Ovarian cancer cell line SKOV3 was purchased. Knockdown GOLM1 and B7-H3 cell lines were obtained through introducing shRNAs by lentivirus package system, while GOLM1 or B7-H3 overexpression cell line was obtained by introducing GOLM1 full-length gene. Furthermore, wound-healing assay and Transwell assay were performed to assess tumor invasion and metastasis abilities; related proteins' expression was quantitated by western blotting, ELISA, and flow cytometry assay. The protein interaction was quantified by co-immunoprecipitation.

Results

GOLM1 has the correlative expression pattern with B7-H3 in ovarian cancer through patient sample databases (R = 0.421). GOLM1 knockdown had minimal impact on B7-H3 mRNA synthesis, while downregulated B7-H3 protein expression on tumor membrane and soluble B7-H3 (sB7-H3) level (p < 0.05) through physical interaction, GOLM1 knockdown, significantly reduce tumor invasion and metastasis in vitro (p < 0.05). Moreover, exogenous sB7-H3 significantly rescued this inhibitory effect. Both GOLM1 and B7-H3 knockdown restrained tumor growth and metastasis in immunodeficient mice and prolonged the survival rate.

Conclusions

GOLM1 acts as an initial oncogenic driving gene by promoting ovarian cancer invasion and metastasis through modulating B7-H3 protein maturation and secretion.

CD276 (B7H3) improve cancer stem cells formation in cervical carcinoma cell lines

Background

Cancer stem cells (CSCs) have been considered as a potential therapeutic target for cervical carcinoma. CD 276 is a well-known immune check point molecular, but its relationship with cervical CSCs was still unclear.

Methods

HeLa cell lines were obtained as cervical carcinoma in vitro model. HeLa cell Sphere formation culture was performed and CD276, OCT4 and SOX2 expression were determined by RT-qPCR. Transiently transfection and siRNA interference were used to modify CD276 expression. HeLa cell colony has been counted and cell proliferation was assessed by MTT assay. The relationship between CD276 and chemotherapy resistance of HeLa cell were evaluated by cisplatin treatment. Additionally, the mice model of xenograft tumor was established and CD276’s function was evaluated in vivo.

Results

Here, we demonstrate that the expression of CD276 is positively correlated with the amount of sphere-forming cells in HeLa cell lines. Overexpression of CD276 causes the inhibition of HeLa cells’ sphere formation, colony formation and cell viability. Meanwhile, the downregulation of CD276 leads to the other way. We also demonstrate that CD276 contributes to the chemotherapy resistance in the cell line. Furthermore, we verify the CD276’s function on HeLa xenotransplantation mice model.

Conclusions

These results suggest that CD276 elevates the self-renewal capacity of HeLa CSCs.

Fibronectin enhances tumor metastasis through B7-H3 in clear cell renal cell carcinoma

B7 homolog 3 (B7-H3) plays an important role in tumor biology, but the molecular mechanism underlying the role of B7-H3 in tumor metastasis remains unclear. In this article, our analysis of The Cancer Genome Atlas database suggested that B7-H3 expression is associated with poor prognosis of patients with clear cell renal cell carcinoma (ccRCC). B7-H3 knockdown affected the expression of metastasis-related genes and significantly suppressed the metastasis of ccRCC cells, but it had no significant effect on the proliferation of ccRCC cells. Database analysis revealed a strong positive correlation between B7-H3 and fibronectin (FN) in ccRCC cells, and further study also confirmed that FN interacts with B7-H3. Silencing FN expression inhibited the migration and invasion of ccRCC cells, whereas exogenous FN promoted the migration and invasion of ccRCC cells, which was accompanied by activation of kinases [namely, phosphorylated (p)-phosphoinositide 3-kinase, p-protein kinase B, p-p38 and p-extracellular regulated protein kinase]. B7-H3 knockdown abolished the prometastatic effect of FN. In conclusion, our data suggest that B7-H3 binds to exogenous FN and promotes the metastasis of ccRCC cells.

Soluble B7-H3 in Ovarian Cancer and Its Predictive Value

The content of the soluble form of protein of the key point of immunity B7-H3 (sB7-H3) in the blood plasma of 75 patients with epithelial ovarian cancer before treatment was measured by ELISA. It is known that B7-H3 belongs to the immunoglobulin superfamily (B7 molecule family) and is involved in the regulation of the immune response mediated by T cells. The sB7-H3 concentration correlated with the clinical and morphological parameters of ovarian cancer. The content of sB7-H3 was higher at the later stages of the disease, in the presence of ascites, and in patients with poorly differentiated ovarian cancer. It was revealed that increased plasma content of sB7-H3 in patients with epithelial ovarian cancer is associated with unfavorable prognosis of the disease. Therefore, sB7-H3 can be used as a prognostic marker in ovarian cancer patients.

A Novel Treatment for Ewing's Sarcoma: Chimeric Antigen Receptor-T Cell Therapy

Ewing's sarcoma (EWS) is a malignant and aggressive tumor type that predominantly occurs in children and adolescents. Traditional treatments such as surgery, radiotherapy and chemotherapy, while successful in the early disease stages, are ineffective in patients with metastases and relapses who often have poor prognosis. Therefore, new treatments for EWS are needed to improve patient's outcomes. Chimeric antigen receptor (CAR)-T cells therapy, a novel adoptive immunotherapy, has been developing over the past few decades, and is increasingly popular in researches and treatments of various cancers. CAR-T cell therapy has been approved by the Food and Drug Administration (FDA) for the treatment of leukemia and lymphoma. Recently, this therapeutic approach has been employed for solid tumors including EWS. In this review, we summarize the safety, specificity and clinical transformation of the treatment targets of EWS, and point out the directions for further research.

Soluble B7-CD28 Family Inhibitory Immune Checkpoint Proteins and Anti-Cancer Immunotherapy

Co-inhibitory B7-CD28 family member proteins negatively regulate T cell responses and are extensively involved in tumor immune evasion. Blockade of classical CTLA-4 (cytotoxic T lymphocyte-associated antigen-4) and PD-1 (programmed cell death protein-1) checkpoint pathways have become the cornerstone of anti-cancer immunotherapy. New inhibitory checkpoint proteins such as B7-H3, B7-H4, and BTLA (B and T lymphocyte attenuator) are being discovered and investigated for their potential in anti-cancer immunotherapy. In addition, soluble forms of these molecules also exist in sera of healthy individuals and elevated levels are found in chronic infections, autoimmune diseases, and cancers. Soluble forms are generated by proteolytic shedding or alternative splicing. Elevated circulating levels of these inhibitory soluble checkpoint molecules in cancer have been correlated with advance stage, metastatic status, and prognosis which underscore their broader involvement in immune regulation. In addition to their potential as biomarker, understanding their mechanism of production, biological activity, and pathological interactions may also pave the way for their clinical use as a therapeutic target. Here we review these aspects of soluble checkpoint molecules and elucidate on their potential for anti-cancer immunotherapy.

Light-Inducible Spatio-Temporal Control of TLR4 and NF-κB-Gluc Reporter in Human Pancreatic Cell Line

Augmented Toll-like receptor 4 (TLR4) expression was found in nearly 70% of patients with pancreatic adenocarcinoma, which is correlated with increased tumorigenesis and progression. In this study, we engineered a new light-oxygen-voltage-sensing (LOV) domain-based optogenetic cell line (opto-TLR4 PANC-1) that enables time-resolved activation of the NF-κB and extracellular-signal regulated kinases (ERK)1/2 signalling pathway upon blue light-sensitive homodimerisation of the TLR4-LOV fusion protein. Continuous stimulation with light indicated strong p65 and ERK1/2 phosphorylation even after 24 h, whereas brief light exposure peaked at 8 h and reached the ground level 24 h post-illumination. The cell line further allows a voltage-dependent TLR4 activation, which can be continuously monitored, turned on by light or off in the dark. Using this cell line, we performed different phenotypic cell-based assays with 2D and 3D cultures, with the aim of controlling cellular activity with spatial and temporal precision. Light exposure enhanced cell attachment, the formation and extension of invadopodia, and cell migration in 3D spheroid cultures, but no significant changes in proliferation or viability could be detected. We conclude that the opto-TLR4 PANC-1 cell line is an ideal tool for investigating the underlying molecular mechanisms of TLR4, thereby providing strategies for new therapeutic options.

Evaluation of the role of soluble B7-H3 in association with membrane B7-H3 expression in gastric adenocarcinoma

BACKGROUND AND OBJECTIVE

Gastric adenocarcinoma (GAC) is one of the most common malignancies. Increasing data have indicated a correlation between soluble B7-H3 (sB7-H3) levels and tumor malignancies. In this study, we aim to investigate the level of soluble B7-H3 in serum of GAC patients. Further, we analyze the correlation between sB7-H3 level and tissue B7-H3 expression and explore the clinical evaluation value of sB7-H3 associated with pathological characteristics and prognosis of GAC patients.

METHODS

One hundred and twenty-eight serum and tissue samples of GAC 20 serum and tissue samples of gastritis patients and 77 serum, 5 tissue samples of healthy controls were collected. The serum levels of sB7-H3 were detected by Enzyme-linked immunosorbent assay (ELISA), while the expression of membrane B7-H3 (mB7-H3) and Ki67 were evaluated by immunohistochemistry. The correlation between sB7-H3 and mB7-H3, sB7-H3 and Ki67, sB7-H3 or mB7-H3 and clinical features were analyzed by Pearson's Chi-square test.

RESULTS

Both serum level of sB7-H3 and tissue B7-H3 of GAC patients were significantly higher than those of gastritis patients and healthy controls. sB7-H3 level was correlated with total B7-H3 expression in tissues (r= 0.2801, P= 0.0014). Notably, the concentration of sB7-H3 was correlated with its expression of membrane form in tumor cells (r= 0.3251, P= 0.002) while not in stromal cells (r= 0.07676, P= 0.3891). Moreover, the levels of sB7-H3 in patients with TNM stage III/IV or with Infiltration depth T3/T4 or with lymph node metastasis were significantly higher than those of patients with TNM stage I/II (P= 0.0020) or with Infiltration depth T1/T2 (P= 0.0169) or with no lymph node metastasis (P= 0.0086). Tumor B7-H3 score, but not stromal B7-H3 score, in patients with TNM stage III/IV or with lymph node metastasis was significantly higher than those with TNM stage I/II (P= 0.0150) or with no lymph node metastasis (P= 0.182).

CONCLUSIONS

Soluble B7-H3 level may reflect the tissue B7-H3 expression on tumor cells of GAC tissues. Elevated level of sB7-H3 in serum suggests poor clinical pathological characteristics of GAC patients.

B7 homologue 3 as a prognostic biomarker and potential therapeutic target in gastrointestinal tumors

The most common digestive system (DS) cancers, including tumors of the gastrointestinal tract (GIT) such as colorectal cancer (CRC), gastric cancer (GC) and esophageal cancer (EC) as well as tumors of DS accessory organs such as pancreatic and liver cancer, are responsible for more than one-third of all cancer-related deaths worldwide, despite the progress that has been achieved in anticancer therapy. Due to these limitations in treatment strategies, oncological research has taken outstanding steps towards a better understanding of cancer cell biological complexity and heterogeneity. These studies led to new molecular target-driven therapeutic approaches. Different in vivo and in vitro studies have revealed significant expression of B7 homologue 3 (B7-H3) among the most common cancers of the GIT, including CRC, GC, and EC, whereas B7-H3 expression in normal healthy tissue of these organs was shown to be absent or minimal. This molecule is able to influence the biological behavior of GIT tumors through the various immunological and nonimmunological molecular mechanisms, and some of them are shown to be the result of B7-H3-related induction of signal transduction pathways, such as Janus kinase 2/signal transducer and activator of transcription 3, phosphatidylinositol 3-kinase/protein kinase B, extracellular signal-regulated kinase, and nuclear factor-κB. B7-H3 exerts an important role in progression, metastasis and resistance to anticancer therapy in these tumors. In addition, the results of many studies suggest that B7-H3 stimulates immune evasion in GIT tumors by suppressing antitumor immune response. Accordingly, it was observed that experimental depletion or inhibition of B7-H3 in gastrointestinal cancers improved antitumor immune response, impaired tumor progression, invasion, angiogenesis, and metastasis and decreased resistance to anticancer therapy. Finally, the high expression of B7-H3 in most common cancers of the GIT was shown to be associated with poor prognosis. In this review, we summarize the established data from different GIT cancer-related studies and suggest that the B7-H3 molecule could be a promising prognostic biomarker and therapeutic target for anticancer immunotherapy in these tumors.

Clinical Research on the Mechanisms Underlying Immune Checkpoints and Tumor Metastasis

This study highlights aspects of the latest clinical research conducted on the relationship between immune checkpoints and tumor metastasis. The overview of each immune checkpoint is divided into the following three sections: 1) structure and expression; 2) immune mechanism related to tumor metastasis; and 3) clinical research related to tumor metastasis. This review expands on the immunological mechanisms of 17 immune checkpoints, including TIM-3, CD47, and OX-40L, that mediate tumor metastasis; evidence shows that most of these immune checkpoints are expressed on the surface of T cells, which mainly exert immunomodulatory effects. Additionally, we have summarized the roles of these immune checkpoints in the diagnosis and treatment of metastatic tumors, as these checkpoints are considered common predictors of metastasis in various cancers such as prostate cancer, non-Hodgkin lymphoma, and melanoma. Moreover, certain immune checkpoints can be used in synergy with PD-1 and CTLA-4, along with the implementation of combination therapies such as LIGHT-VTR and anti-PD-1 antibodies. Presently, most monoclonal antibodies generated against immune checkpoints are under investigation as part of ongoing preclinical or clinical trials conducted to evaluate their efficacy and safety to establish a better combination treatment strategy; however, no significant progress has been made regarding monoclonal antibody targeting of CD28, VISTA, or VTCN1. The application of immune checkpoint inhibitors in early stage tumors to prevent tumor metastasis warrants further evidence; the immune-related adverse events should be considered before combination therapy. This review aims to elucidate the mechanisms of immune checkpoint and the clinical progress on their use in metastatic tumors reported over the last 5 years, which may provide insights into the development of novel therapeutic strategies that will assist with the utilization of various immune checkpoint inhibitors.

B7-H3/CD276: An Emerging Cancer Immunotherapy

Immunotherapy aiming at suppressing tumor development by relying on modifying or strengthening the immune system prevails among cancer treatments and points out a new direction for cancer therapy. B7 homolog 3 protein (B7-H3, also known as CD276), a newly identified immunoregulatory protein member of the B7 family, is an attractive and promising target for cancer immunotherapy because it is overexpressed in tumor tissues while showing limited expression in normal tissues and participating in tumor microenvironment (TME) shaping and development. Thus far, numerous B7-H3-based immunotherapy strategies have demonstrated potent antitumor activity and acceptable safety profiles in preclinical models. Herein, we present the expression and biological function of B7-H3 in distinct cancer and normal cells, as well as B7-H3-mediated signal pathways in cancer cells and B7-H3-based tumor immunotherapy strategies. This review provides a comprehensive overview that encompasses B7-H3’s role in TME to its potential as a target in cancer immunotherapy.

The Inhibition of B7H3 by 2-HG Accumulation Is Associated With Downregulation of VEGFA in IDH Mutated Gliomas

B7H3 (also known as CD276) is a co-stimulator checkpoint protein of the cell surface B7 superfamily. Recently, the function beyond immune regulation of B7H3 has been widely studied. However, the expression preference and the regulation mechanism underlying B7H3 in different subtypes of gliomas is rarely understood. We show here that B7H3 expression is significantly decreased in IDH-mutated gliomas and in cultured IDH1-R132H glioma cells. Accumulation of 2-HG leads to a remarkable downregulation of B7H3 protein and the activity of IDH1-R132H mutant is responsible for B7H3 reduction in glioma cells. Inhibition of autophagy by inhibitors like leupeptin, chloroquine (CQ), and Bafilomycin A1 (Baf-A1) blocks the degradation of B7H3 in glioma cells. In the meantime, the autophagy flux is more active with higher LC3B-II and lower p62 in IDH1-R132H glioma cells than in IDH1-WT cells. Furthermore, sequence alignment analysis reveals potential LC3-interacting region (LIR) motifs “F-V-S/N-I/V” in B7H3. Moreover, B7H3 interacts with p62 and CQ treatment significantly enhances this interaction. Additionally, we find that B7H3 is positively correlated with VEGFA and MMP2 by bioinformatics analysis in gliomas. B7H3 and VEGFA are decreased in IDH-mutated gliomas and further reduced in 2-HG^high gliomas compared to 2-HG^low glioma sections by IHC staining. Our study demonstrates that B7H3 is preferentially overexpressed in IDH wild-type gliomas and could serve as a potential theranostic target for the precise treatment of glioma patients with wild-type IDH.

Advances in immunotherapeutic targets for childhood cancers: A focus on glypican-2 and B7-H3

Cancer immunotherapies have revolutionized how we can treat adult malignancies and are being translated to pediatric oncology. Chimeric antigen receptor T-cell therapy and bispecific antibodies targeting CD19 have shown success for the treatment of pediatric patients with B-cell acute lymphoblastic leukemia. Anti-GD2 monoclonal antibody has demonstrated efficacy in neuroblastoma. In this review, we summarize the immunotherapeutic agents that have been approved for treating childhood cancers and provide an updated review of molecules expressed by pediatric cancers that are under study or are emerging candidates for future immunotherapies. Advances in our knowledge of tumor immunology and in genome profiling of cancers has led to the identification of new tumor-specific/associated antigens. While cell surface antigens are normally targeted in a major histocompatibility complex (MHC)-independent manner using antibody-based therapies, intracellular antigens are normally targeted with MHC-dependent T cell therapies. Glypican 2 (GPC2) and B7-H3 (CD276) are two cell surface antigens that are expressed by a variety of pediatric tumors such as neuroblastoma and potentially can have a positive impact on the treatment of pediatric cancers in the clinic.

B7-H3 suppresses doxorubicin-induced senescence-like growth arrest in colorectal cancer through the AKT/TM4SF1/SIRT1 pathway

Emerging evidence suggests that cellular senescence induced by chemotherapy has been recognized as a new weapon for cancer therapy. This study aimed to research novel functions of B7-H3 in cellular senescence induced by a low dose of doxorubicin (DOX) in colorectal cancer (CRC). Here, our results demonstrated that B7-H3 knockdown promoted, while B7-H3 overexpression inhibited, DOX-induced cellular senescence. B7-H3 knockdown dramatically enhanced the growth arrest of CRC cells after low-dose DOX treatment, but B7-H3 overexpression had the opposite effect. By RNA-seq analysis and western blot, we showed that B7-H3 prevented cellular senescence and growth arrest through the AKT/TM4SF1/SIRT1 pathway. Blocking the AKT/TM4SF1/SIRT1 pathway dramatically reversed B7-H3-induced resistance to cellular senescence. More importantly, B7-H3 inhibited DOX-induced cellular senescence of CRC cells in vivo. Therefore, targeting B7-H3 or the B7-H3/AKT/TM4SF1/SIRT1 pathway might be a new strategy for promoting cellular senescence-like growth arrest during drug treatment in CRC.

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.

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.