A review of B7-H3 and B7-H4 immune molecules and their role in ovarian cancer

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.

Current Landscape of Cancer Immunotherapy: Harnessing the Immune Arsenal to Overcome Immune Evasion

Cancer immune evasion represents a leading hallmark of cancer, posing a significant obstacle to the development of successful anticancer therapies. However, the landscape of cancer treatment has significantly evolved, transitioning into the era of immunotherapy from conventional methods such as surgical resection, radiotherapy, chemotherapy, and targeted drug therapy. Immunotherapy has emerged as a pivotal component in cancer treatment, harnessing the body's immune system to combat cancer and offering improved prognostic outcomes for numerous patients. The remarkable success of immunotherapy has spurred significant efforts to enhance the clinical efficacy of existing agents and strategies. Several immunotherapeutic approaches have received approval for targeted cancer treatments, while others are currently in preclinical and clinical trials. This review explores recent progress in unraveling the mechanisms of cancer immune evasion and evaluates the clinical effectiveness of diverse immunotherapy strategies, including cancer vaccines, adoptive cell therapy, and antibody-based treatments. It encompasses both established treatments and those currently under investigation, providing a comprehensive overview of efforts to combat cancer through immunological approaches. Additionally, the article emphasizes the current developments, limitations, and challenges in cancer immunotherapy. Furthermore, by integrating analyses of cancer immunotherapy resistance mechanisms and exploring combination strategies and personalized approaches, it offers valuable insights crucial for the development of novel anticancer immunotherapeutic strategies.

VCAM-1 complements CA-125 in detecting recurrent ovarian cancer

BACKGROUND

Close to three-quarters of ovarian cancer cases are frequently diagnosed at an advanced stage, with more than 70% of them failing to respond to primary therapy and relapsing within 5 years. There is an urgent need to identify strategies for early detection of ovarian cancer recurrence, which may lead to earlier intervention and better outcomes.

METHODS

A customized magnetic bead-based 8-plex immunoassay was evaluated using a Bio-Plex 200 Suspension Array System. Target protein levels were analyzed in sera from 58 patients diagnosed with advanced ovarian cancer (including 34 primary and 24 recurrent tumors) and 46 healthy controls. The clinical performance of these biomarkers was evaluated individually and in combination for their ability to detect recurrent ovarian cancer.

RESULTS

An 8-plex immunoassay was evaluated with high analytical performance suitable for biomarker validation studies. Logistic regression modeling selected a two-marker panel of CA-125 and VCAM-1 that improved the performance of CA-125 alone in detecting recurrent ovarian cancer (AUC: 0.813 versus 0.700). At a fixed specificity of 83%, the two-marker panel significantly improved sensitivity in separating primary from recurrent tumors (70.8% versus 37.5%, P = 0.004), demonstrating that VCAM-1 was significantly complementary to CA-125 in detecting recurrent ovarian cancer.

CONCLUSIONS

A two-marker panel of CA-125 and VCAM-1 showed strong diagnostic performance and improvement over the use of CA-125 alone in detecting recurrent ovarian cancer. The experimental results warrant further clinical validation to determine their role in the early detection of recurrent ovarian cancer.

Evaluation of serum B7-H3 expression, ultrasound and clinical characteristics to predict the risk of cervical lymph node metastases in papillary thyroid carcinoma by nomogram

BACKGROUND

Improving the preoperative diagnosis of cervical lymph node metastasis (LNM) will help improve the clinical outcomes of papillary thyroid carcinoma (PTC) patients. B7-H3, as an immune checkpoint of the B7 family, is highly expressed in PTC tissues and related to LNM and prognosis. We aimed to explore the clinical values of serum B7-H3 (sB7-H3) in predicting LNM in PTC by a nomogram prediction model.

METHODS

From September 2019 to May 2021, a total of 344 PTC patients with primary surgery in our hospital were enrolled in this research. Enzyme-linked Immunosorbent Assay (ELISA) was used to detect sB7-H3 from the peripheral blood of PTC patients and normal controls. We created a nomogram prediction model in combination with sB7-H3 expression, clinical and ultrasound characteristics to predict LNM in the early stage.

RESULTS

Gender (p = 0.001), age (p = 0.015), tumor size (p < 0.001), number of tumors (p = 0.021) and sB7-H3 expression (p = 0.003) were independent risk factors for LNM in PTC. All the factors were included in the nomogram. The area under the curve (AUC) was 73.9% (95% CI, 68.12%-79.69%).

CONCLUSION

The nomogram is helpful in assessing the risk of LNM in PTC. sB7-H3 has excellent potential in predicting LNM in patients with PTC as an adjunctive ultrasound tool.

B7 family protein glycosylation: Promising novel targets in tumor treatment

Cancer immunotherapy, including the inhibition of immune checkpoints, improves the tumor immune microenvironment and is an effective tool for cancer therapy. More effective and alternative inhibitory targets are critical for successful immune checkpoint blockade therapy. The interaction of the immunomodulatory ligand B7 family with corresponding receptors induces or inhibits T cell responses by sending co-stimulatory and co-inhibitory signals respectively. Blocking the glycosylation of the B7 family members PD-L1, PD-L2, B7-H3, and B7-H4 inhibited the self-stability and receptor binding of these immune checkpoint proteins, leading to immunosuppression and rapid tumor progression. Therefore, regulation of glycosylation may be the "golden key" to relieve tumor immunosuppression. The exploration of a more precise glycosylation regulation mechanism and glycan structure of B7 family proteins is conducive to the discovery and clinical application of antibodies and small molecule inhibitors.

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.

Co-deficiency of B7-H3 and B7-H4 identifies high CD8 + T cell infiltration and better prognosis in pancreatic cancer

Background

Immunotherapy is a novel hotspot for the treatment of pancreatic adenocarcinoma (PAAD). However, potential biomarkers which could identify the inflamed tumor microenvironment (TME) are urgently required.

Methods

In the present study, we measured the levels of B7-H3, B7-H4, and major tumor-infiltrating immune cells (TIICs) using bioinformatics analyses and immunohistochemistry (IHC) staining on PAAD samples represented in the tissue microarray (TMA) format. Statistical analysis and figures exhibition were performed using R 4.1.0, SPSS 26.0, and GraphPad Prism 6.0.

Results

B7-H3 and B7-H4 were up-regulated in PAAD compared with para-tumor tissues, and their expression exhibited no tight correlation in PAAD tissues. B7-H3 and B7-H4 were lowly expressed in well-differentiated PAAD tissues and correlated with poorly differentiated grades. Besides, single B7-H3 or B7-H4 expression exhibited limited prognostic value, but co-deficiency of B7-H3 and B7-H4 predicted a better prognosis in PAAD. Moreover, co-deficiency of B7-H3 and B7-H4 indicated immuno-hot tumors with high CD8 + T cell infiltration.

Conclusions

Overall, combined B7-H3 and B7-H4 expression is a promising stratification strategy to assess prognosis and immunogenicity in PAAD, which could be used as a novel classifier in clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09294-w.

Immunotherapy in Ovarian Cancer: Thinking Beyond PD-1/PD-L1

Ovarian cancer (OC) is the most lethal gynecologic malignancy, affecting approximately 1 in 70 women with only 45% surviving 5 years after diagnosis. This disease typically presents at an advanced stage, and optimal debulking with platinum-based chemotherapy remains the cornerstone of management. Although most ovarian cancer patients will respond effectively to current management, 70% of them will eventually develop recurrence and novel therapeutic strategies are needed. There is a rationale for immune-oncological treatments (IO) in the managements of patients with OC. Many OC tumors demonstrate tumor infiltrating lymphocytes (TILs) and the degree of TIL infiltration is strongly and reproducibly correlated with survival. Unfortunately, results to date have been disappointing in relapsed OC. Trials have reported very modest single activity with various antibodies targeting PD-1 or PD-L1 resulting in response rate ranging from 4% to 15%. This may be due to the highly immunosuppressive TME of the disease, a low tumor mutational burden and low PD-L1 expression. There is an urgent need to improve our understanding of the immune microenvironment in OC in order to develop effective therapies. This review will discuss immune subpopulations in OC microenvironment, current immunotherapy modalities targeting these immune subsets and data from clinical trials testing IO treatments in OC and its combination with other therapeutic agents.

Associations of B7-H3 and B7-H4 Expression in Ductal Carcinoma In Situ of the Breast With Clinicopathologic Features and T-Cell Infiltration

B7-H3 and B7-H4 play an inhibitory role in T-cell function by limiting proliferation and cytokine production. Information about B7-H3 and B7-H4 expression in ductal carcinoma in situ (DCIS) remains uncertain. The objective of this study was to evaluate the expression levels of B7-H3 and B7-H4 in DCIS and their associations with clinicopathologic features and T-cell infiltration. B7-H3 and B7-H4 mRNA and protein expression levels in 8 pairs of DCIS tissues and matched normal adjacent tissues were examined by RNAscope in situ hybridization and immunohistochemistry analysis. Immunohistochemical staining of B7-H3, B7-H4, CD3, and CD8 was performed for 79 DCIS samples using tissue microarray. RNAscope in situ hybridization and immunohistochemistry analysis revealed that expression levels of B7-H3 and B7-H4 in DCIS tissues were higher than those in corresponding normal tissues. B7-H3 and B7-H4 mRNA and protein appeared to be mainly expressed in DCIS carcinoma cells. High B7-H3 and B7-H4 expression was observed in 58 (73.4%) and 62 (78.5%) cases with DCIS, respectively. High B7-H3 expression was significantly associated with high-nuclear grade and presence of comedo-type necrosis (both P<0.05). B7-H3 expression in HR/HER2 subtype was higher than that in HR/HER2 subtype (P<0.05). B7-H3 and B7-H4 expression levels were negatively related to the density of CD3 and CD8 T-cell infiltrates. B7-H3 and B7-H4 may play an important role in immune surveillance mechanisms of DCIS. They might be useful targets to develop immune-based therapy to alter or prevent DCIS progression.

The Regulatory Cross-Talk between microRNAs and Novel Members of the B7 Family in Human Diseases: A Scoping Review

The members of the B7 family, as immune checkpoint molecules, can substantially regulate immune responses. Since microRNAs (miRs) can regulate gene expression post-transcriptionally, we conducted a scoping review to summarize and discuss the regulatory cross-talk between miRs and new B7 family immune checkpoint molecules, i.e., B7-H3, B7-H4, B7-H5, butyrophilin like 2 (BTNL2), B7-H6, B7-H7, and immunoglobulin like domain containing receptor 2 (ILDR2). The current study was performed using a six-stage methodology structure and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. PubMed, Embase, Scopus, Cochrane, ProQuest, and Google Scholar were systematically searched to obtain the relevant records to 5 November 2020. Two authors independently reviewed the obtained records and extracted the desired data. After quantitative and qualitative analyses, we used bioinformatics approaches to extend our knowledge about the regulatory cross-talk between miRs and the abovementioned B7 family members. Twenty-seven articles were identified that fulfilled the inclusion criteria. Studies with different designs reported gene–miR regulatory axes in various cancer and non-cancer diseases. The regulatory cross-talk between the aforementioned B7 family molecules and miRs might provide valuable insights into the pathogenesis of various human diseases.

Immune function of miR-214 and its application prospects as molecular marker

MicroRNAs are a class of evolutionary conserved non-coding small RNAs that play key regulatory roles at the post-transcriptional level. In recent years, studies have shown that miR-214 plays an important role in regulating several biological processes such as cell proliferation and differentiation, tumorigenesis, inflammation and immunity, and it has become a hotspot in the miRNA field. In this review, the regulatory functions of miR-214 in the proliferation, differentiation and functional activities of immune-related cells, such as dendritic cells, T cells and NK cells, were briefly reviewed. Also, the mechanisms of miR-214 involved in tumor immunity, inflammatory regulation and antivirus were discussed. Finally, the value and application prospects of miR-214 as a molecular marker in inflammation and tumor related diseases were analyzed briefly. We hope it can provide reference for further study on the mechanism and application of miR-214.

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

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

PBK phosphorylates MSL1 to elicit epigenetic modulation of CD276 in nasopharyngeal carcinoma

CD276 (also known as B7-H3, an immune checkpoint molecule) is aberrantly overexpressed in many cancers. However, the upregulation mechanism and in particular, whether oncogenic signaling has a role, is unclear. Here we demonstrate that a pro-oncogenic kinase PBK, the expression of which is associated with immune infiltration in nasopharyngeal carcinoma (NPC), stimulates the expression of CD276 epigenetically. Mechanistically, PBK phosphorylates MSL1 and enhances the interaction between MSL1 and MSL2, MSL3, and KAT8, the components of the MSL complex. As a consequence, PBK promotes the enrichment of MSL complex on CD276 promoter, leading to the increased histone H4 K16 acetylation and the activation of CD276 transcription. In addition, we show that CD276 is highly upregulated and associated with immune infiltrating levels in NPC. Collectively, our findings describe a novel PBK/MSL1/CD276 signaling axis, which may play an important role in immune evasion of NPC and may be targeted for cancer immunotherapy.

Emerging Targets of Immunotherapy in Gynecologic Cancer

Although programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) and cytotoxic T lymphocyte antigen-4 (CTLA-4) have been successfully applied in the treatment of tumors, their efficiency is still not high enough. New immune targets need to be identified in order to seek alternative treatment strategies for patients with refractory tumors. Immune targets can be divided into stimulating and inhibiting molecules according to their function after receptor-ligand binding. We herein present a compendious summary of emerging immune targets in gynecologic tumors. These targets included coinhibitory molecules, such as T cell immunoglobulin-3 (TIM-3), T cell immunoglobulin and ITIM domain (TIGIT), lymphocyte activation gene-3 (LAG-3), V-type immunoglobulin domain-containing suppressor of T cell activation (VISTA), and B7-H3 and B7-H4, and co-stimulatory molecules, such as CD27, OX40, 4-1BB, CD40, glucocorticoid-induced tumor necrosis factor receptor (GITR) and inducible co-stimulator (ICOS). In this review, the characteristics and preclinical/clinical progress of gynecological malignancies are briefly discussed. However, the potential mechanisms and interactions of immune targets need to be elucidated in further studies.

B7H3-Directed Intraperitoneal Radioimmunotherapy With Radioiodinated Omburtamab for Desmoplastic Small Round Cell Tumor and Other Peritoneal Tumors: Results of a Phase I Study

PURPOSE

Desmoplastic small round cell tumor (DSRCT), a rare sarcoma of adolescents/young adults primarily involving the peritoneum, has a long-term survival of < 20% despite aggressive multimodality treatment. B7H3 is expressed on DSRCT cell surface, providing a target for antibody-based immunotherapy.

PATIENTS AND METHODS

In this phase I study, we evaluated the safety, pharmacokinetics, and biodistribution of intraperitoneal (IP) radioimmunotherapy (RIT) with the anti-B7H3 murine monoclonal antibody ¹³¹I-omburtamab in patients with DSRCT or other B7H3-expressing tumors involving the peritoneum. After thyroid blockade, patients received ¹³¹I-omburtamab as a single IP injection at escalated activities from 1.11 to 3.33/GBq/m². A prior tracer dose of IP 74 MBq¹²⁴I-omburtamab was used for radioimmuno-positron emission tomography imaging. Each injection was followed by IP saline infusion.

RESULTS

Fifty-two patients (48, three, and one with DSRCT, peritoneal rhabdomyosarcoma, and Ewing sarcoma, respectively) received IP ¹³¹I-omburtamab administered on an outpatient basis. Maximum tolerated dose was not reached; there were no dose-limiting toxicities. Major related adverse events were transient: grade 4 neutropenia (n = 2 patients) and thrombocytopenia (n = 1), and grade 1 (10%) and grade 2 (52%) pain lasting < 2 hours related to saline infusion. Hypothyroidism was not observed, and antidrug antibody was elicited in 5%. Mean (± SD) projected peritoneal residence time was 22.4 ± 7.9 hours. Mean projected absorbed doses for ¹³¹I-omburtamab based on ¹²⁴I-omburtamab dosimetry to normal organs were low and well within tolerable limits. More than 80% ¹³¹I remained protein bound in blood 66 hours after RIT. On the basis of peritoneal dose and feasibility for outpatient administration, the recommended phase II activity was established at 2.96 GBq/m². Patients with DSRCT receiving standard whole-abdominal radiotherapy after RIT did not experience unexpected toxicity.

CONCLUSION

IP RIT ¹³¹I-omburtamab was well tolerated with minimal toxicities. Radiation exposure to normal organs was low, making combination therapy with other anticancer therapies feasible.

NK-Cell-Mediated Targeting of Various Solid Tumors Using a B7-H3 Tri-Specific Killer Engager In Vitro and In Vivo

We improved the bispecific antibody platform that primarily engages natural killer (NK) cells to kill cancer cells through antibody-dependent cellular cytotoxicity (ADCC) by adding IL-15 as a crosslinker that expands and self-sustains the effector NK cell population. The overall goal was to target B7-H3, an established marker predominantly expressed on cancer cells and minimally expressed on normal cells, and prove that it could target cancer cells in vitro and inhibit tumor growth in vivo. The tri-specific killer engager (TriKE^TM) was assembled by DNA shuffling and ligation using DNA encoding a camelid anti-CD16 antibody fragment, a wild-type IL-15 moiety, and an anti-B7-H3 scFv (clone 376.96). The expressed and purified cam1615B7H3 protein was tested for in vitro NK cell activity against a variety of tumors and in vivo against a tagged human MA-148 ovarian cancer cell line grafted in NSG mice. cam1615B7H3 showed specific NK cell expansion, high killing activity across a range of B7-H3+ carcinomas, and the ability to mediate growth inhibition of aggressive ovarian cancer in vivo. cam1615B7H3 TriKE improves NK cell function, expansion, targeted cytotoxicity against various types of B7-H3-positive human cancer cell lines, and delivers an anti-cancer effect in vivo in a solid tumor setting.

Clinical characterization, genetic profiling, and immune infiltration of TOX in diffuse gliomas

Background

Immunotherapies targeting glioblastoma (GBM) have led to significant improvements in patient outcomes. TOX is closely associated with the immune environment surrounding tumors, but its role in gliomas is not fully understood.

Methods

Using data from The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA), we analyzed the transcriptomes of 1691 WHO grade I-IV human glioma samples. The R language was used to perform most of the statistical analyses. Somatic mutations and somatic copy number variation (CNV) were analyzed using GISTIC 2.0.

Results

TOX was down-regulated in malignant gliomas compared to low grade gliomas, and upregulated in the proneural and IDH mutant subtypes of GBM. TOX^low tumours are associated with the loss of PTEN and amplification of EGFR, while TOX^high tumours harbor frequent mutations in IDH1 (91%). TOX was highly expressed in leading edge regions of tumours. Gene ontology and pathway analyses demonstrated that TOX was enriched in multiple immune related processes including lymphocyte migration in GBM. Finally, TOX had a negative association with the infiltration of several immune cell types in the tumour microenvironment.

Conclusion

TOX has the potential to be a new prognostic marker for GBM.

Improving the Clinical Significance of Preclinical Immunotherapy Studies through Incorporating Tumor Microenvironment-like Conditions

Frequently, the results generated when testing novel antitumor immunotherapies in vitro do not correlate with data collected in in vivo models and/or in clinical settings. It is our hypothesis that this discrepancy is caused by the use of in vitro conditions, such as normoxia, a two-dimensional surface, optimal growth media, and lack of cell complexity and heterogeneity. These conditions do not accurately reflect the tumor microenvironment (TME) that the tested immunotherapeutic strategies experience in vivo While there are many variables which can have an impact upon the antitumor efficacy of an immunotherapy, the immunosuppressive TME is one in which several of the conditions commonly found in vivo can be mimicked in vitro These conditions, which include hypoxia, low pH, low glucose, presence of adenosine, cell complexity and heterogeneity, as well as the three-dimensional structure of TME, can all affect immune cell-tumor cell interactions. Here, we discuss the impact that these conditions, either individually or in combination, can have on these interactions. Furthermore, we propose that performing in vitro assays under TME-like conditions improves the clinical relevance of the yielded results. This, in turn, contributes to accelerate the speed, reduce the cost, and increase efficiency of screening novel immunotherapies and eventually the development of prospective clinical trials.

B7-H3 and B7-H4 Expression in Breast Cancer and Their Association with Clinicopathological Variables and T Cell Infiltration

OBJECTIVES

B7-H3 and B7-H4 proteins are expressed in breast cancer tissues, but their relationships with respect to tumor immune surveillance and outcomes in breast cancer are not conclusive.

METHODS

We first examined B7-H3 and B7-H4 mRNA expression in the Genotype-Tissue Expression (GTEx) and The Cancer Genome Atlas (TCGA) datasets. Next, mRNA and protein expression were assessed by RNAscope in situ hybridization (ISH) and immunohistochemistry in 10 pairs of breast cancer and matched normal tissues. Immunohistochemical staining of B7-H3, B7-H4, CD3, and CD8 was performed in tissue microarray slides containing 198 breast cancer samples. Association of B7-H3 and B7-H4 expression with survival was verified using the publicly accessible BreastMark tool.

RESULTS

B7-H3 and B7-H4 mRNA expression were significantly higher in breast cancer samples in the TCGA dataset than in normal breast tissues in the GTEx dataset. RNAscope ISH and immunohistochemistry showed that B7-H3 and B7-H4 mRNA and protein appeared to be mainly expressed in cancer cells. Expression of B7-H3 and B7-H4 tended to be associated with low-density scores of stromal tumor-infiltrating lymphocytes (TILs) as well as molecular subtypes. Expressions of B7-H3 and B7-H4 were negatively correlated with stromal CD3+ and CD8+ T cell infiltration density. B7-H3 and B7-H4 expression was not associated with survival, which was verified by BreastMark analysis.

CONCLUSION

Expression levels of B7-H3 and B7-H4 were independent of clinical outcomes of breast cancer. There was an inverse relationship between the expression of B7-H3 and B7-H4 in breast cancer and the density of stromal TILs and CD8+ T lymphocytes. This inverse relationship may represent a promising target in the field of breast cancer immunotherapy.

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

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

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

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

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

An improved method to build lung cancer PDX models by surgical resection samples and its association with B7-H3 expression

Background

Patient-derived xenograft (PDX) models are biologically stable and can accurately reflect the primary tumor in histopathology and genetic expression in many cancers. In lung cancer, the models' engraftment rate by endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) and computed tomography (CT)-guided biopsy is exceptionally low, and this limits the development of PDX models in lung cancer research. In this study, we aimed to improve the traditional method, and explore the feasibility and convenience of establishing lung cancer PDX models using the samples directly from surgical resection. We also endeavored to explore the correlation between PDX formation and primary tumor B7-H3 protein expression.

Methods

From September 2017 to July 2018, 24 patients were enrolled in this study. The pathological diagnoses were as follows: 15 adenocarcinomas, 7 squamous cell carcinomas, 1 large cell carcinoma, and 1 small cell carcinoma. The tumor tissues were cut into sizes of 2×2×2 mm³/fragment and inoculated subcutaneously into immunodeficiency mice with a trocar needle. The engrafted tumors were passaged at least 3 generations, and B7-H3 IHC staining was performed on primary tumors. To explore the correlation between PDX formation and B7-H3 protein expression, we also performed H&E staining to evaluate whether the established PDX models could retain the histological features of the primary tumor.

Results

Xenograft formation success was achieved in 19 out of 24 cases (79.2%). The time between implantation to tumor formation was an average of 81.5 days (27-154 days) in P1, an average of 44.4 days (14-122 days) in P2, and an average of 26.9 days (12-75 days) in P3. The diameter of the tumor was associated with tumor engraftment: the longer the diameter, the easier engraftment formation was (P=0.0342). The data also suggests that lung cancers with B7-H3 expression greatly induced PDX formation (P=0.0375). The histological characters of each passage resembled the primary tumors.

Conclusions

This study shows that the samples from carefully selected lung cancer by surgical resection can be used for the establishment of PDX models with a high success rate; this improved method is closer to actual clinical work. Compared with the same kind of research, the success rate of the xenograft indicates significant improvement, so this improved method is suitable for promotion and application. The results of H&E staining showed that the histological characters of each passage resembled the primary tumors. Furthermore, the diameter of the tumor was associated with tumor engraftment, and higher B7-H3 expression demonstrated a statistically significant difference compared with the PDX model formation.

LncRNA NEAT1 sponges miR-214 to regulate M2 macrophage polarization by regulation of B7-H3 in multiple myeloma

BACKGROUND

LncRNA NEAT1 was associated with the tumorigenesis of multiple myeloma (MM). However, the mechanisms of M2 macrophage polarization involved with NEAT1 in MM are still unknown.

METHODS

Bone marrow samples, multiple myeloma cells RPMI 8226 and monocyte cell line THP-1 were used in this study. The expression of NEAT1 and miR-214 was modified by transfection with the shNEAT1 or miR-214 inhibitor. The expression of NEAT1, miR-214 and B7-H3 in MM patient tissues and cells was analyzed by RT-qPCR. ELISA assay was used to determine the release of B7-H3 in the supernatant of cell culture. The patient survival curve was analyzed using Kaplan-Meier method. The macrophage polarization markers were examined by RT-qPCR and western blotting. The interaction between NEAT1, miR-214 and B7-H3 was analyzed by Dual-Luciferase reporter and RIP assays. AG490 was used to block the JAK2/STAT3 signaling. Co-culture of THP-1 and RPMI 8226 cells was used for macrophage polarization.

RESULTS

NEAT1 and B7-H3 were up-regulated, but miR-214 was obviously down-regulated in MM patients. B7-H3, NEAT1 and miR-214 were associated with overall survival time of MM patients. NEAT1 silencing induced miR-214 and inhibited the expression and release of B7-H3 and then suppressed M2 macrophage polarization via inhibiting the JAK2/STAT3 signaling. NEAT1 directly targeted miR-214, and miR-214 directly bound to B7-H3. MiR-214 inhibitor reversed the down-regulation and release of B7-H3 and M2 macrophage polarization caused by shNEAT1. The specific JAK2/STAT3 signaling inhibitor AG490 abrogated M2 macrophage polarization.

CONCLUSION

NEAT1 promoted M2 macrophage polarization by sponging miR-214 and then regulating B7-H3, thus accelerating MM progression via the JAK2/STAT3 signaling pathway. Our study revealed novel mechanisms of M2 macrophage polarization and provided new potential clinical therapeutic targets for MM.

B7-H3 participates in human salivary gland epithelial cells apoptosis through NF-κB pathway in primary Sjögren's syndrome

Background

Primary Sjögren’s syndrome (pSS) is an autoimmune disorder mainly characterized by exocrine gland injury. Costimulatory molecules play an important role in immune-regulatory networks. Although B7 family costimulatory molecules were previously discovered in human salivary gland epithelial (HSGE) cells in pSS, the effects of the B7 family member B7-H3 (CD276) have not been well elucidated. Thus, this study aimed to investigate the role and mechanism of B7-H3 in HSGE cells in pSS.

Methods

The expression of B7-H3, B7-H1, PD-1 in serum, saliva and salivary gland were examined by immunohistochemistry (IHC) and enzyme-linked immunosorbent assay (ELISA). Immunofluorescence was used to test the expression and distribution of B7-H3, AQP5 and CK-8 in salivary gland tissues. Flow cytometry, Cell Counting Kit 8 (CCK-8) and western blot (WB) were performed to research the apoptotic, proliferative and inflammatory effects of B7-H3 in primary HSGE cells and HSGE cell lines.

Results

Our results showed that the expression of PD-1, B7-H1 and B7-H3 in peripheral blood, and salivary glands in pSS patients was higher than that in healthy controls, which was positive correlation with the grade of the salivary glands. The expression of B7-H3 in saliva was higher in pSS patients than that in healthy controls, which was detected with the most significant difference of them. The expression of B7-H3 in primary HSGE cells of pSS patients was significantly higher than healthy controls. B7-H3 increased activity of NF-κB pathway and promoted inflammation of HSGE cells, decreasing the expression of AQP5. Furthermore, B7-H3 overexpression inhibited proliferation and induced apoptosis in HSGE cell lines.

Conclusion

B7-H3 could promote inflammation and induce apoptosis of HSGE cells by activating NF-κB pathway, which might be a promising therapeutic target for pSS.

B7H3 regulates differentiation and serves as a potential biomarker and theranostic target for human glioblastoma

B7H3 (CD276), a co-stimulator molecule of the cell surface B7 protein superfamily, is expressed on glioblastomas (GBM). Recently, B7H3 functions beyond immune costimulation have been demonstrated. However, the mechanisms underlying B7H3 function are diverse and not well understood. GBM tumors contain undifferentiated self-renewing cells, which confound therapeutic attempts. We investigated the role of B7H3 in the regulation of GBM cell differentiation and the regulatory pathways involved. Analysis of public databases (TCGA, Rembrandt, and GEO NCBI) and RNA sequencing were performed to explore the role of B7H3 in GBM. Knockdown and overexpression of B7H3, were used to verify the downstream pathway in vitro. Further studies in vivo were performed to support the new finding. Bioinformatics analysis identified a correlation between the expression of B7H3, the expression of glioma self-renewing cell (GSC)-related genes, and MYC expression. These observations were verified by RNA-sequencing analyses in primary GBM cell lines. In vitro knockdown of B7H3-induced differentiation, associated with downregulation of SMAD6 (a TGF-β pathway inhibitor) and enhancement of SMAD1 phosphorylation-induced SMAD4 expression. Importantly, activation of the TGF-β pathway resulted in downregulation of MYC expression. In vivo assays conducted in a human GBM cell line xenograft mouse model demonstrated that B7H3 knockdown decreased MYC expression and inhibited tumor growth. B7H3 knockdown could regulate GBM differentiation by modulating MYC expression. So, B7H3 could serve as a potential theranostic target for the treatment of patients with GBM.

B7-H3 and B7-H4 expression in phyllodes tumors of the breast detected by RNA in situ hybridization and immunohistochemistry: Association with clinicopathological features and T-cell infiltration

Phyllodes tumors are rare biphasic breast tumors with the potential for both local recurrence and distant metastasis. The aberrant expression of B7-H3 and B7-H4 B7 molecules could be potential targets for future development of immunotherapeutic approaches. This work was undertaken to evaluate the expression of B7-H3 and B7-H4 in phyllodes tumors and assess the association with the grade and clinical behavior of phyllodes tumors. In addition, the roles of B7-H3 and B7-H4 in the regulation of tumor immune surveillance were evaluated by assessing the relationship between B7-H3/B7-H4 expression and T-cell infiltration. The messenger RNA and protein expression of B7-H3/B7-H4 were determined by RNAscope in situ hybridization and immunohistochemistry, respectively, in 101 phyllodes tumors (60 benign, 26 borderline, and 15 malignant) using a tissue microarray. Immunohistochemistry for CD3 and CD8 was also performed. B7-H3 messenger RNA and protein appeared to be concentrated mainly in the stromal compartment of phyllodes tumors. However, B7-H4 messenger RNA and protein were undetectable in the stromal compartment of phyllodes tumors. Stromal B7-H3 messenger RNA and protein expression were noted in 10 (16.7%) and 31 (51.7%) of 60 benign phyllodes tumors, 12 (46.1%) and 20 (76.9%) of 26 borderline phyllodes tumors, and 10 (66.7%) and 13 (86.7%) of 15 malignant phyllodes tumors, respectively. Stromal B7-H3 messenger RNA and protein expression increased as phyllodes tumors progressed from benign to borderline and finally to the malignant grade (Pearson's R = 0.411, p < 0.001 and Pearson's R = 0.293, p = 0.003, respectively). The recurrence rate was higher in the stromal B7-H3 messenger RNA or protein-positive group than in the negative group, but this difference was not significant. Stromal B7-H3 protein expression inversely correlated with the densities of CD3⁺ and CD8⁺ T-cell infiltrates ( p = 0.001 and p = 0.027, respectively). These results suggest that B7-H3 is involved in the progression of phyllodes tumors and may contribute to their immune surveillance.

Genetic and clinical characterization of B7-H3 (CD276) expression and epigenetic regulation in diffuse brain glioma

Gliomas are the most common malignant tumors of the brain. Immune checkpoints have been increasingly emphasized as targets for treating malignant tumors. B7-H3 has been identified as an immune checkpoint that shows potential value for targeting therapies. We set out to characterize the expression pattern and biological function of B7-H3 in brain gliomas using high-throughput data obtained from the Chinese Glioma Genome Atlas (CGGA) and the Cancer Genome Atlas (TCGA) projects. B7-H3 was upregulated more in higher-grade gliomas than that in lower-grade gliomas in both CGGA and TCGA datasets. Isocitrate dehydrogenase (IDH) mutation seemed to exert significant influence on B7-H3 expression in gliomas but led to quite different results between grade II gliomas and higher-grade gliomas. In addition to IDH, methylation of B7-H3 promoter and microRNA-29 family also showed a potential regulatory effect on B7-H3 expression. Gene ontology analysis revealed that B7-H3 was associated with mitotic cell cycle, cell proliferation and immune response. Further investigation suggested that B7-H3 was mostly involved in the Toll-like receptor signaling pathway. Survival analysis indicated that B7-H3 was an independent unfavorable prognosticator for glioma patients in both CGGA and TCGA datasets. B7-H3 expression is regulated by multiple mechanisms and is potentially involved in the T-cell receptor signaling pathway. Higher B7-H3 expression indicates a worse prognosis for glioma patients, which warrants further research into the development of inhibitors for targeting this immune checkpoint, but we still need to be cautious about immune checkpoint inhibition for central nervous system tumors.

B7-H4 overexpression contributes to poor prognosis and drug-resistance in triple-negative breast cancer

Background

The expression of the immunoregulatory protein B7-H4 has been reported in many types of cancer, including breast cancer. However, its role in triple-negative breast cancer (TNBC), especially its correlation with patients’ prognosis and chemoresistance remains unclear.

Methods

The expression of B7-H4 in TNBC tissues and cell lines were measured with Real-Time PCR and western blotting. 65 cases of TNBC tissue samples and adjacent non-tumor tissue samples were analyzed by immunochemistry to demonstrate the correlation between the B7-H4 expression and clinicopathological characteristics. In vitro studies assessed mAb MIH43 alone and in combination with transfecting B7-H4 siRNA on the growth of chemosensitive and chemoresistant TNBC cell lines by CCK-8 and apoptotic enzyme-linked immunosorbent assay (ELISA).

Results

B7-H4 expression was detected positive in 59 of 65 (90.8%) different stage TNBC patients, especially in the samples of recurrence TNBC patients after receiving neoadjuvant chemotherapy treatment. Survival curves showed that patients with B7-H4 overexpression had significantly shorter survival and recurrence time than those with low B7-H4 expression (p < 0.005). Univariate and multivariate COX regression analysis demonstrated that B7-H4 was an independent predictor for advanced tumor stage. The monoclonal antibody of B7-H4 has the potential anti-proliferative effects on inhibiting the chemoresistant TNBC cell lines and increasing the sensitivity of TNBC cell lines to doxorubicin, paclitaxel or carboplatin. RNAi-mediated silencing of B7-H4 in TNBC cells enhanced drug-induced apoptosis via inhibiting PTEN/PI3K/AKT pathway, whereas reexpression of B7-H4 in B7-H4 knockdown and low B7-H4 expressing cells increased the phosphorylation of PI3K and AKT along with restoration of PETN expression.

Conclusions

Our data show that B7-H4 is a biomarker indicative of a poor prognosis in TNBC patients and at least partially downregulated in chemoresistance via PTEN/PI3K/AKT pathway. Targeting B7-H4 might provide an attractive therapeutic approach specifically for TNBC patients.

Electronic supplementary material

The online version of this article (10.1186/s12935-018-0597-9) contains supplementary material, which is available to authorized users.

Comprehensive molecular profiling of the B7 family in gastrointestinal cancer

OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Perspectives of Immune Suppression in the Tumor Microenvironment Promoting Oral Malignancy

Introduction

In order to survive, cancers control immune systems and evade immune detection using mediators consisting of immune checkpoint molecules and cellular systems associated with immune suppression.

Methodology

During the development of cancer and chronic infections, the immune checkpoints and cellular components including regulatory T cells, myeloid derived suppressor cells and cancer associated fibroblasts are often enhanced as a mechanism of immune subversion and have therefore become very important therapeutic targets.

Conclusion

In this review, we will discuss the complexity of immune-suppressive mechanisms in the tumor milieu of cancers, including oral malignancy.

Regulation of cancer immune escape: The roles of miRNAs in immune checkpoint proteins

Immune checkpoint proteins (ICPs) are regulators of immune system. The ICP dysregulation silences the host immune response to cancer-specific antigens, contributing to the occurrence and progress of various cancers. MiRNAs are regulatory molecules and function in mRNA silencing and post-transcriptional regulation of gene expression. MiRNAs that modulate the immunity via ICPs have received increasing attention. Many studies have shown that the expressions of ICPs are directly or indirectly repressed by miRNAs in multiple types of cancers. MiRNAs are also subject to regulation by ICPs. In this review, recent studies of the relationship between miRNAs and ICPs (including the PD-1, PD-L1, CTLA-4, ICOS, B7-1, B7-2, B7-H2, B7-H3, CD27, CD70, CD40, and CD40L) in cancer immune escape are comprehensively discussed, which provide critical detailed mechanistic insights into the functions of the miRNA-ICP axes and their effects on immune escape, and will be beneficial for the potential applications of immune checkpoint therapy and miRNA-based guidance for personalized medicine as well as for predicting the prognosis.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

New B7 Family Checkpoints in Human Cancers

T cells are the main effector cells in immune response against tumors. The activation of T cells is regulated by the innate immune system through positive and negative costimulatory molecules. Targeting immune checkpoint regulators such as programmed cell death 1 (PD-1)/PD-1 ligand 1 (PD-L1) and CTL antigen 4 (CTLA-4) has achieved notable benefit in a variety of cancers, which leads to multiple clinical trials with antibodies targeting the other related B7/CD28 family members. Recently, five new B7 family ligands, B7-H3, B7-H4, B7-H5, B7-H6, and B7-H7, were identified. Here we review recent understanding of new B7 family checkpoint molecules as they have come to the front of cancer research with the concept that tumor cells exploit them to escape immune surveillance. The aim of this article is to address the structure and expression of the new B7 family molecules as well as their roles in controlling and suppressing immune responses of T cells as well as NK cells. We also discuss clinical significance and contribution of these checkpoint expressions in human cancers. Mol Cancer Ther; 16(7); 1203-11. ©2017 AACR.

Nanotechnology and Glycosaminoglycans: Paving the Way Forward for Ovarian Cancer Intervention

Ovarian cancer (OC) has gained a great deal of attention due to its aggressive proliferative capabilities, high death rates and poor treatment outcomes, rendering the disease the ultimate lethal gynaecological cancer. Nanotechnology provides a promising avenue to combat this malignancy by the niche fabrication of optimally-structured nanomedicines that ensure potent delivery of chemotherapeutics to OC, employing nanocarriers to act as "intelligent" drug delivery vehicles, functionalized with active targeting approaches for precision delivery of chemotherapeutics to overexpressed biomarkers on cancer cells. Recently, much focus has been implemented to optimize these active targeting mechanisms for treatment/diagnostic purposes employing nanocarriers. This two-part article aims to review the latest advances in active target-based OC interventions, where the impact of the newest antibody, aptamer and folate functionalization on OC detection and treatment is discussed in contrast to the limitations of this targeting mechanism. Furthermore, we discuss the latest advances in nanocarrier based drug delivery in OC, highlighting their commercial/clinical viability of these systems beyond the realms of research. Lastly, in the second section of this review, we comprehensively discussed a focus shift in OC targeting from the well-studied OC cells to the vastly neglected extracellular matrix and motivate the potential for glycosaminoglycans (GAGs) as a more focused extracellular molecular target.

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-H4 promotes tumor growth and metastatic progression in lung cancer by impacting cell proliferation and survival

Aberrant expression of B7-H4 occurs across a broad spectrum of human cancers. The aim of this study was to investigate the key role of B7-H4 during tumorigenesis and metastasis of human lung cancer. Our data showed that the shRNA-mediated disruption of B7-H4 markedly inhibited tumor cell proliferation, invasion and migration, increased cell apoptosis and arrested cell cycle at G0/G1. These changes were accompanied by a marked increase in Bax and caspase-3/caspase-8, but a decrease in Bcl-2, cyclinD1 and activation of AKT. In addition, our shRNA-mediated disruption of B7-H4 led to a marked decrease in tumor growth in the immune-compromised mice. Importantly, B7-H4 was expressed in 53.33% of lung carcinomas from our patient cohort (n = 90), but not in any of adjacent non-cancerous tissues, according to our IHC analyses. In particular, B7-H4 expression appeared to be associated with lymph node metastasis (P = 0.008) and TNM stage (P = 0.012). Taken together, our study demonstrates a strong promoting role of B7-H4 in lung tumor growth, progression and metastasis, and supports its potential as a therapeutic target for the treatment of the disease.

Immune Cell Population in Ovarian Tumor Microenvironment

Ovarian cancer, the third most common with highest mortality rates gynecological malignancy among women in China, is characterized by a unique tumor immune microenvironment. Immune-cell population infiltrated into the tumor tissue among patients with ovarian cancer are associated positively or negatively with antitumor activity. The imbalance between immune activation and immune suppression can result in oncogenesis and cancer progression. Therefore, intense investigation of the immunologic mechanism of ovarian cancer is urgently needed, and a comprehensive understanding of the network in which immune cells interact with the microenvironment, tumor cells and each other will greatly promote the development of more effective immunotherapies for ovarian cancer. In this review, we will focus on the main immune-cell population in ovarian tumor microenvironment, discuss their role in tumor progression and try to give the readers a new perspective in finding more promising therapeutic targets for cancers.

B7-H3 is related to tumor progression in ovarian cancer

B7-H3, a co-stimulatory molecule, has been found expressed in ovarian cancer, but its role and mechanism is not clear. In this study, we further verified the expression of B7-H3 in ovarian carcinoma and normal epithelial ovarian tissues. Three ovarian cancer cell lines, A2780, SKOV3 and HO8910 were selected to explore the effects of B7-H3 on proliferation, apoptosis, migration and invasion. We found that B7-H3 was mainly located in the cytoplasm of ovarian cancer cells as determined by immunofluorescence staining. The ability of cell invasion, migration, proliferation decreased after silencing B7-H3 whereas the apoptosis increased, which was related to the upregulation of Bax, caspase-8, cleaved caspase-8 and the downregulation of Bcl-2, Bcl-xl, matrix metalloproteinase-2 (MMP2) by western blotting. In addition, B7-H3 enhanced the H08910 cell capacities in invasion, migration and proliferation. Expression of the phosphorylation signal transducer and activator of transcription 3 (pStat3) molecules and their upstream molecules phosphorylation Janus kinase 2 (pJak2) were significantly increased. In order to investigate whether B7-H3 plays a role in this pathway, we treated the overexpressed HO8910 cells with AG490 (inhibitors of Jak2). Our findings revealed that B7-H3 affect ovarian cancer progression through the Jak2/Stat3 pathway, indicating that B7-H3 has the potential to be a useful prognostic marker.

Roles of immune inhibitory molecule B7-H4 in cervical cancer

Recent studies have reported that the immune-regulatory protein B7-H4 is highly expressed in various types of cancer, but little is known concerning its roles in cervical cancer. In the present study, we investigated the expression of B7-H4 in human tissues and serum samples, and explored the effects of B7-H4 on proliferation, apoptosis, migration and invasion of cervical cancer cell lines, including SiHa and HeLa. We found that B7-H4 was mainly located in the cytoplasm of cervical cancer cells as determined by immunofluorescence staining. Serum B7-H4 (sB7-H4) was overexpressed in patients with cervical intraepithelial neoplasia (CIN) and cervical cancer, and the area under the ROC curve (AUC) was 0.955. There was no statistical significance between B7-H4 expression and clinicopathological factors in cervical cancer tissue samples. B7-H4 promoted the proliferation of SiHa and HeLa cells, and protected them from apoptosis, which was related to the upregulation of E7, phosphorylated Rb (pRb), E2F, P16, P21, Bcl-2 and the downregulation of Rb, cleaved PARP and cleaved caspase-3 as determined by western blotting. In addition, B7-H4 increased the ability of cell migration and invasion by targeting angiogenic factors, matrix metalloproteinase (MMP)-2, MMP-9 and vascular endothelial growth factor (VEGF) as determined by RT-PCR. Our findings revealed that B7-H4 has the potential to be a useful prognostic marker. In addition, B7-H4 plays important roles in proliferation, apoptosis, migration and invasion, indicating that B7-H4 can serve as a new therapeutic target for cervical cancer.

B7-H4 deficiency in salivary gland of patients with primary Sjögren's syndrome impairs the regulatory effect on T cells

AIM

Our previous study confirmed the defect of B7-H4 expression in peripheral blood and salivary glands of patients with primary Sjögren's syndrome (pSS). The aim of this study was to analyze the effect of the deficit expression of B7-H4 on CD4⁺ T cells.

METHODS

CD4⁺ T cells were purified by magnetic-activated cell sorting MACS. The proliferation and cytokine production of CD4⁺ T cells co-cultured with purified salivary gland epithelial cells (SGECs) from pSS or non-SS sicca syndrome were detected.

RESULTS

By co-culturing the gland cells with CD4⁺ T cells, we found the proliferation of CD4⁺ T cells was significantly suppressed. The effect was weaker when SGECs from pSS patients were used compared to that from non-pSS sicca syndrome controls. Simultaneously, the productions of cytokines interleukin (IL)-5, IL-13, IL-17A, IL-6 in supernatant were reduced and also SGECs from pSS patients decreased them less than that from non-SS controls.

CONCLUSIONS

The decrease of B7-H4 expression in salivary glands of SS patients contributes to the defect of negatively regulating the inflammation caused by CD4⁺ T cells, thereby providing new insights into the role of B7-H4 in the inflammatory process of salivary glands in SS.

Increased B7-H4 expression during esophageal squamous cell carcinogenesis is associated with IL-6/STAT3 signaling pathway activation in mice

B7-homolog 4 (B7-H4), one of the costimulatory molecules of the B7 family, has been reported to be widely expressed in multiple types of cancer tissues, and to be important in tumor progression and poor prognosis. However, the role of B7-H4 in esophageal precancerous lesions has not been elucidated yet. In the present study, a model of esophageal squamous cell carcinogenesis was established in 208 C57BL/6 mice by 4-nitroquinoline-1-oxide (4NQO) drinking water of mice, and the changes in the expression of B7-H4 during the whole pathological process were investigated. Hematoxylin and eosin staining results demonstrated that the pathological stage was exacerbated with the increase in time of 4NQO-mediated carcinogenesis induction, and the pathological features were similar to those observed in humans. Immunohistochemistry results revealed that B7-H4 expression was upregulated and positively correlated with pathological stage (P<0.0001) as well as with infiltration of cluster of differentiation (CD) 11b⁺ macrophage cells (P=0.0002). In addition, B7-H4 messenger RNA expression increased in the esophagi of model mice compared with that of control mice, which was positively associated with the gene expression of interleukin (IL)-6 and signal transducer and activator of transcription 3 (STAT3), according to the results of reverse transcription-quantitative polymerase chain reaction analysis. Similarly, B7-H4 protein expression was upregulated in the esophageal tissues of model mice in comparison with that of control mice, and was positively associated with IL-6 expression and STAT3 phosphorylation. In conclusion, the present data suggested that B7-H4 expression increased during esophageal squamous cell carcinogenesis in mice in association with IL-6/STAT3 signaling pathway activation.

Decreased expression of B7-H3 reduces the glycolytic capacity and sensitizes breast cancer cells to AKT/mTOR inhibitors

B7 family proteins are important immune response regulators, and can mediate oncogenic signaling and cancer development. We have used human triple-negative breast cancer cell lines with different expression levels of B7-H3 to evaluate its effects on the sensitivity to 22 different anticancer compounds in a drug screen. API-2 (triciribidine) and everolimus (RAD-001), two inhibitors that target the PI3K/AKT/mTOR pathway, showed enhanced inhibition of cell viability and proliferation in B7-H3 knockdown tumor cells compared to their B7-H3 expressing counterparts. Similar inhibition was seen in control cells treated with an anti-B7-H3 monoclonal antibody. In B7-H3 overexpressing cells, the effects of the two drugs were reduced, supported also by in vivo experiments in which B7-H3 overexpressing xenografts were less sensitive to everolimus than control tumors. In API-2 and everolimus-treated B7-H3 overexpressing cells, phospho-mTOR levels were decreased. However, phosphorylation of p70S6K was differentially regulated in B7-H3 cells treated with API-2 or everolimus, suggesting a different B7-H3-mediated mechanism downstream of mTOR. Both API-2 and everolimus decreased the glycolysis of the cells, whereas knockdown of B7-H3 decreased and B7-H3 overexpression increased the glycolytic capacity. In conclusion, we have unveiled a previously unknown relationship between B7-H3 expression and glycolytic capacity in tumor cells, and found that B7-H3 confers resistance to API-2 and everolimus. The results provide novel insights into the function of B7-H3 in cancer, and suggest that targeting of B7-H3 may be a novel alternative to improve current anticancer therapies.

B7-H3 regulates lipid metabolism of lung cancer through SREBP1-mediated expression of FASN

B7-H3 is a glycoprotein overexpressed in cancer, but its functional contribution in this setting remains poorly understood. In the present study, we identified that the overexpression of B7-H3 in lung cancer resulted in aberrant lipid metabolism via SREBP-1/FASN signaling pathway. Immunohistochemical analysis of tissue microarrays revealed that approximately 80.4% (37/46) of lung cancer tissues were positive for B7-H3 accompanying poor prognosis. Notably, Oil red O staining and total triglyceride assay exhibited that down-regulation of B7-H3 decreased lipid synthesis in lung cancer A549 and H446 cell lines. Mechanistic investigations showed that B7-H3 modulated the expression of FASN, a fatty acid synthase, specifically. Furthermore, deletion of B7-H3 down-regulated the mRNA and protein levels of SREBP-1, a transcription factor governing the expression of FASN. Finally, correlation analysis between expression levels of B7-H3 and FASN exhibited a positive correlation in clinical lung cancer tissues. Overall, we conclude that B7-H3 hijacks SREBP-1/FASN signaling mediating abnormal lipid metabolism in lung cancer. Our finding provides new insights into the function and mechanism of B7-H3 in the development of lung cancer.

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

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

[Immunological aspects of ovarian cancer: Therapeutic perspectives]

Ovarian cancer is recognized by the immunological system of its host. Initially, it is effective to destroy and eliminate the cancer. But gradually, resistant tumor cells more aggressive and those able to protect themselves by inducing immune tolerance will be selected. Immunotherapy to be effective should consider both components of immune response with an action on cytotoxic immune effectors and action on tolerance mechanisms. The manipulations of the immune system should be cautious, because the immune effects are not isolated. A theoretically efficient handling may simultaneously cause an adverse effect which was not envisaged and could neutralize the benefits of treatment. Knowledge of tolerance mechanisms set up by the tumor is for the clinician a prerequisite before they prescribe these treatments. For each cancer, the knowledge of its immunological status is a prerequisite to propose adapted immunological therapies.

B7-H4 facilitates proliferation of esophageal squamous cell carcinoma cells through promoting interleukin-6/signal transducer and activator of transcription 3 pathway activation

B7‐H4, one of the costimulatory molecules of the B7 family, has been found to be widely expressed in many kinds of tumor tissues and to play an important part in tumor progression and poor prognosis. However, the role of B7‐H4 in esophageal squamous cell carcinoma (ESCC) cells has not been elucidated. In this study, we found that, compared with normal esophageal tissue, B7‐H4 was highly expressed in three ESCC cell lines, Eca109, TE1, and TE13. B7‐H4 silenced cells suppressed cellular proliferation and colony formation. Additionally, compared with control cells, B7‐H4 silenced cells showed higher apoptosis rates, Bcl‐2 and Survivin upregulation, and BAX downregulation. Further study revealed that B7‐H4 silenced cells also showed reduction in interleukin‐6 (IL‐6) secretion, signal transducer and activator of transcription 3 (STAT3) activation, and p‐STAT3 translocation from cytoplasm to nucleus. Moreover, B7‐H4 depletion inhibited the IL‐6 secretion of control cells but not JAK2/STAT3 inhibitor FLLL32‐treated cells. Interleukin‐6 receptor antagonist tocilizumab did not block the p‐JAK2 or p‐STAT3 downregulation induced by B7‐H4 silence. It was suggested that B7‐H4 silence suppressed IL‐6 secretion through JAK2/STAT3 inactivation. Furthermore, cell proliferation and colony formation were downregulated by tocilizumab in control cells but not in B7‐H4 silenced cells, indicating that IL‐6 upregulation induced by B7‐H4 was necessary for cell growth. On the other hand, B7‐H4 expression was downregulated by tocilizumab. In all, our study provided the first evidence that B7‐H4 facilitated ESCC cell proliferation through promoting IL‐6/STAT3 positive loopback pathway activation.

B7-H3 and B7-H4 are independent predictors of a poor prognosis in patients with pancreatic cancer

B7-H3 and B7-H4 belong to the peripheral membrane protein B7 family and are hypothesized to regulate immunity. These proteins are expressed in human pancreatic cancer (PC), but their prognostic significance is poorly understood. The present study examined the association between B7-H3 and B7-H4 expression and the overall survival time in patients with PC that underwent surgery at the Second Affiliated Hospital to Zhengzhou University between April 2000 and January 2009. Immunohistochemical analysis demonstrated that B7-H3 and B7-H4 were expressed in 35 (88%) and 30 (75%) tumor tissue samples, respectively, which were obtained from 40 patients with PC. Statistical analysis revealed that B7-H3 expression was associated with an early tumor-node-metastasis stage (stage I and II; P<0.01), and B7-H4 expression was associated with tumors located in the body and tail of the pancreas (P<0.01) and lymph node metastasis (P=0.02). In addition, using Spearman's rank correlation coefficient, the present study demonstrated a positive correlation between B7-H3 expression and B7-H4 expression (r=0.37; P=0.02) in tumor samples. B7-H4 expression (P=0.01), tumors located in the pancreatic body and tail (P<0.01), lymph node metastasis (P=0.02) and combined B7-H3 and B7-H4 expression (P<0.01) were indicators of a poor overall survival time. However, solitary B7-H4 expression (P=0.03) and combined B7-H3 and B7-H4 expression (P=0.04) remained significant prognostic factors following adjustment for other prognostic factors in a multivariate Cox's proportional hazards regression model. Therefore, the present results indicate that solitary B7-H4 expression and a combination of B7-H3 and B7-H4 expression are independent predictors of a poor prognosis in patients with PC.