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

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

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

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

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

Cancer vaccines and immunotherapeutic approaches in hepatobiliary and pancreatic cancers

Hepatobiliary and pancreatic cancers along with other gastrointestinal malignancies remain the leading cause of cancer-related deaths worldwide. Strategies developed in the recent years on immunotherapy and cancer vaccines in the setting of primary liver cancer as well as in pancreatic cancer are the scope of this review. Significance of orthotopic and autochthonous animal models which mimic and/or closely reflect human malignancies allowing for a prompt and trustworthy analysis of new therapeutics is underlined. Combinational approaches that on one hand, specifically target a defined cancer-driving pathway, and on the other hand, restore the functions of immune cells, which effector functions are often suppressed by a tumor milieu, are shown to have the strongest perspectives and future directions. Among combinational immunotherapeutic approaches a personalized- and individual cancer case-based therapy is of special importance.

Prognostic value of B7-H3 expression in patients with solid tumors: a meta-analysis

Increasing evidence suggests B7-H3 is aberrantly expressed in various cancers, though its prognostic significance in solid tumors remains controversial. We therefore performed a meta-analysis to clarify the prognostic value of B7-H3 expression in human solid tumors. The PubMed and Embase databases were searched, and 28 studies involving 4623 patients were ultimately included in the analysis. Hazard ratios (HRs) with 95% confidence intervals (CIs) were utilized as effect estimates to evaluate the association between B7-H3 expression and overall survival (OS), progression-free survival (PFS) and recurrence-free survival (RFS). The pooled results showed B7-H3 was associated with poor OS (HR = 1.58; 95% CI: 1.32–1.90; P < 0.00001) and PFS (HR = 1.67; 95% CI: 1.05–2.65; P = 0.031), but not RFS (HR = 1.17; 95% CI: 0.89–1.53; P = 0.267). These results suggest B7-H3 is a negative predictor of OS and PFS in patients with solid tumors. B7-H3 may thus be a useful prognostic biomarker and therapeutic target for human solid tumors. However, further studies will be needed to more precisely determine the prognostic value of B7 H3 expression.

Artemether Regulates Chemosensitivity to Doxorubicin via Regulation of B7-H3 in Human Neuroblastoma Cells

BACKGROUND Artemether, originally used for malaria, exhibits potential therapeutic efficacy against several types of cancer, including gastric cancer, hepatocellular carcinoma, and gliomas. In this study, we investigated the role and mechanism of artemether on drug resistance of neuroblastoma cells. MATERIAL AND METHODS Cell viability and proliferation were determined by CCK-8 and EdU incorporation assay, respectively. Gene expression was measured by real-time PCR and Western blot analysis. RESULTS Our results revealed that artemether treatment remarkably inhibited the proliferation of neuroblastoma cell lines SH-SY5Y, SK-N-SH, and SK-N-BE2. In addition, co-treatment of tumor cells with artemether and doxorubicin significantly reduced cell viability and DNA synthesis compared with doxorubicin-treated cells. On the molecular level, we found that combined treatment with artemether and doxorubicin suppressed the expression of B7-H3 both at the mRNA and protein levels. In addition, artemether failed to sensitize tumor cells to doxorubicin in SH-SY5Y cells overexpressing B7-H3. CONCLUSIONS Artemether-mediated inhibition of B7-H3 may contribute to doxorubicin sensitivity in neuroblastoma cells, suggesting that artemether could serve as a potential therapeutic option for neuroblastoma.

B7-H3 promotes the proliferation, migration and invasiveness of cervical cancer cells and is an indicator of poor prognosis

B7-H3 is an immune regulatory molecule whose aberrant expression in tumors is associated with adverse outcomes. Upregulation of B7-H3 may promote tumor cell proliferation and metastasis in vitro, but the role of B7-H3 in cervical cancer has not yet been investigated. We measured B7-H3 expression in 90 cervical cancer patient and 20 non‑cervical lesion patient tissues using immunohistochemistry and in 30 cervical cancer patient and 30 healthy donor blood samples using ELISA. The association of B7-H3 expression and the prognosis of cervical cancer patients was investigated. B7-H3 knockdown in CaSki and SiHa cell lines was performed using small hairpin (sh)RNA lentiviral transfection and B7-H3 overexpression in CaSki and HeLa cell lines was performed using plasmid-vector lentivirus transduction. Cell proliferation, invasion and migration were then measured using MTT and Transwell assays in vitro. B7-H3 expression was significantly higher in the cervical cancer tissues compared to that noted in the normal cervical tissues (mean 72.22 vs. 15.00%; p<0.001). Using Kaplan‑Meier and Cox analyses, our data revealed that patients with strong intensity staining were significantly more likely to have a worse prognosis. The B7-H3 level in cervical cancer patient blood was significantly higher than that in the normal donors (13.41±6.12 vs. 9.90±3.16 ng/ml; p=0.007). MTT assay revealed that high expression of B7-H3 promoted cervical cancer cell proliferation. Transwell assay data revealed that high expression of B7-H3 enhanced cervical cancer cell migration and invasion (CaSki, p=0.003; HeLa, p=0.03). In conclusion, expression of B7-H3 was significantly higher in cervical cancer tissues compared to normal cervical tissues, and this high expression was associated with worse prognosis for cervical cancer patients. In addition, B7-H3 promoted proliferation, invasion and migration of cervical cancer and may be a potential target for treating cervical cancer.

B7-H3 Expression in NSCLC and Its Association with B7-H4, PD-L1 and Tumor-Infiltrating Lymphocytes

Purpose: The immune checkpoint PD-1 and its receptor B7-H1 (PD-L1) are successful therapeutic targets in cancer but less is known about other B7 family members. Here, we determined the expression level of B7-H3 protein in non-small cell lung cancer (NSCLC) and evaluated its association with tumor-infiltrating lymphocytes (TIL), PD-L1, B7-H4, and major clinicopathologic characteristics is in 3 NSCLC cohorts.Experimental design: We used multiplexed automated quantitative immunofluorescence (QIF) to assess the levels of B7-H3, PD-L1, B7-H4, and TILs in 634 NSCLC cases with validated antibodies. Associations between the marker levels, major clinicopathologic variables and survival were analyzed.Results: Expression of B7-H3 protein was found in 80.4% (510/634) of the cases. High B7-H3 protein level (top 10 percentile) was associated with poor overall survival (P < 0.05). Elevated B7-H3 was consistently associated with smoking history across the 3 cohorts, but not with sex, age, clinical stage, and histology. Coexpression of B7-H3 and PD-L1 was found in 17.6% of the cases (112/634) and with B7-H4 in 10% (63/634). B7-H4 and PD-L1 were simultaneously detected only in 1.8% of NSCLCs (12/634). The expression of B7-H3 was not associated with the levels of CD3-, CD8-, and CD20-positive TILs.Conclusions: B7-H3 protein is expressed in the majority of NSCLCs and is associated with smoking history. High levels of B7-H3 protein have a negative prognostic impact in lung carcinomas. Coexpression of B7-H3 with PD-L1 and B7-H4 is relatively low, suggesting a nonredundant biological role of these targets. Clin Cancer Res; 23(17); 5202-9. ©2017 AACR.

The expanding repertoire of targets for immune checkpoint inhibition in bladder cancer: What lies beneath the tip of the iceberg, PD-L1

Over the last decade, a new understanding of tumor-immune system interplay has been ushered in, lead in large part by the discovery of immune checkpoints mediated through B7-CD28 family interactions. Therapeutic blockade of the PD-L1 immune checkpoint pathway has already shown great success as a cancer immunotherapy for advanced urothelial carcinoma, leading to durable clinical remissions in an otherwise incurable disease. There are newly described members of the B7-CD28 family including B7-H3, B7x, and HHLA2. These ligands are thought to play an essential role in suppressing T-cell response, leading to immune tolerance of tumors. This feature makes them attractive targets for novel immunotherapy treatment paradigms. Here, we review the literature of current strategies and future directions of immune checkpoint blockade therapy for bladder cancer.

Immunotherapy of hepatocellular carcinoma using chimeric antigen receptors and bispecific antibodies

Hepatocellular carcinoma (HCC) is one of the most lethal cancers worldwide with an overall survival rate of less than 15% in developed countries. Despite attempts at new therapeutic strategies, the majority of patients succumb to this cancer. Buttressed by the highly successful clinical impact in melanoma, immunotherapy is gaining momentum as the next treatment modality for many human cancers. Chimeric antigen receptors (CAR) contain the antigen binding moieties of a monoclonal antibody and the co-stimulatory and signaling domains associated with effector receptor signaling. Bispecific antibodies (BsAb) combine the binding specificities of two different monoclonal antibodies, one activating a receptor on a killer effector cell, while the other engaging a tumor-associated antigen to initiate tumor cytotoxicity. In this review, we survey the HCC targets for which CARs and bispecific antibodies have been generated. The pros and cons of these targets for T-cell and Natural Killer cell based immunotherapy will be discussed.

The third group of the B7-CD28 immune checkpoint family: HHLA2, TMIGD2, B7x, and B7-H3

The B7-CD28 family of ligands and receptors play important roles in T-cell co-stimulation and co-inhibition. Phylogenetically they can be divided into three groups. The recent discovery of the new molecules (B7-H3 [CD276], B7x [B7-H4/B7S1], and HHLA2 [B7H7/B7-H5]/TMIGD2 [IGPR-1/CD28H]) of the group III has expanded therapeutic possibilities for the treatment of human diseases. In this review, we describe the discovery, structure, and function of B7-H3, B7x, HHLA2, and TMIGD2 in immune regulation. We also discuss their roles in important pathological states such as cancers, autoimmune diseases, transplantation, and infection. Various immunotherapeutical approaches are emerging including antagonistic monoclonal antibodies and agonistic fusion proteins to inhibit or potentiate these molecules and pathways in cancers and autoimmune diseases.

Overexpression of CD39 in hepatocellular carcinoma is an independent indicator of poor outcome after radical resection

Nucleoside triphosphate diphosphohydrolase-1 (ENTPD1/CD39) is the rate-limiting enzyme in a cascade leading to the generation of immunosuppressive adenosine and plays an important role in tumor progression. This study aimed to evaluate the expression of CD39 and CD39Foxp3 regulatory T cells (Tregs) and to determine their prognostic role in patients with hepatocellular carcinoma (HCC) after radical resection.Immunohistochemistry (IHC) and double IHC were used to analyze CD39 expression or the expression of CD39 and Foxp3 in a cohort of 324 HCC patients who underwent curative resection. The quantification of CD39 expression levels was determined using a computerized image analysis system and was evaluated by mean optical density (MOD), which corresponded to the positive staining intensity of CD39. The number of positive Foxp3 cells and both CD39 and Foxp3 positive cells in each 1-mm-diameter cylinder were counted under high-power magnification (×400). The "minimum P value" approach was used to obtain the optimal cutoff value for the best separation between groups of patients in relation to time to recurrence (TTR) or overall survival (OS). The expression of CD39 in HCC cell lines with stepwise metastatic potential and in human umbilical vein endothelial cells was determined by reverse transcription-polymerase chain reaction, Western blotting, and immunofluorescence. The SPSS 17.0 statistical package was used for statistics.CD39 was principally expressed on vascular endothelial cells, macrophagocytes, Tregs, and tumor cells in HCC. Compared with paired peritumoral tissues, tumoral tissues had a significantly higher expression level of CD39 (P < 0.0001). Overexpression of tumoral CD39 was related to increased tumor recurrence and shortened overall survival. Furthermore, the expression level of peritumoral CD39 showed a prognostic role in TTR and OS. Double IHC showed that tumoral tissues had significantly higher Foxp3Tregs and CD39Foxp3Tregs count per 1 mm core (14.1659 vs 4.9877, P = 0.001; 11.5254 vs 3.3930, P < 0.001) and a higher CD39Foxp3/Foxp3 ratio compared with paired peritumoral tissues. CD39Foxp3Tregs were a better prognosticator than CD39Tregs for TTR.Overexpression of CD39 protein in HCC was an independent predictor of poor outcome after radical resection. The CD39Foxp3Tregs count added prognostic power to Foxp3Tregs, providing a potential target for tumor immunotherapy.

B7H3 ameliorates LPS-induced acute lung injury via attenuation of neutrophil migration and infiltration

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are characterized by an excessive inflammatory response within the lungs and severely impaired gas exchange resulting from alveolar-capillary barrier disruption and pulmonary edema. The costimulatory protein B7H3 functions as both a costimulator and coinhibitor to regulate the adaptive and innate immune response, thus participating in the development of microbial sepsis and pneumococcal meningitis. However, it is unclear whether B7H3 exerts a beneficial or detrimental role during ALI. In the present study we examined the impact of B7H3 on pulmonary inflammatory response, polymorphonuclear neutrophil (PMN) influx, and lung tissue damage in a murine model of lipopolysaccharide (LPS)-induced direct ALI. Treatment with B7H3 protected mice against LPS-induced ALI, with significantly attenuated pulmonary PMN infiltration, decreased lung myeloperoxidase (MPO) activity, reduced bronchoalveolar lavage fluid (BALF) protein content, and ameliorated lung pathological changes. In addition, B7H3 significantly diminished LPS-stimulated PMN chemoattractant CXCL2 production by inhibiting NF-κB p65 phosphorylation, and substantially attenuated LPS-induced PMN chemotaxis and transendothelial migration by down-regulating CXCR2 and Mac-1 expression. These results demonstrate that B7H3 substantially ameliorates LPS-induced ALI and this protection afforded by B7H3 is predominantly associated with its inhibitory effect on pulmonary PMN migration and infiltration.

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

Many studies have demonstrated a relationship between soluble B7-H3 (sB7-H3) and the poor prognosis of patients with malignant tumors, and increasing evidence has shown a connection between sB7-H3 and NF-κB in tumor progression. In the present study, we demonstrate for the first time that sB7-H3 promotes the invasion and metastasis of pancreatic carcinoma cells through the TLR4/NF-κB pathway. In this study, we observed that sB7-H3 was highly expressed in mB7-H3-positive pancreatic carcinoma (PCa) cells. Exogenous sB7-H3 significantly increased NF-κB activity and promoted the migration and invasion of PCa cells. Further studies proved that sB7-H3 first up-regulated TLR4 expression, then activated NF-κB signaling and finally promoted IL-8 and VEGF expression. In contrast, the silencing of TLR4 using a stable short hairpin RNA significantly decreased the sB7-H3-induced activity of NF-κB and the expression of IL-8 and VEGF in PCa cells. In vivo animal experiments further demonstrated that TLR4-knock-down tumor cells displayed a decreased ability to metastasize compared with the control tumor cells after being induced by sB7-H3. Collectively, these results demonstrate that sB7-H3 promotes invasion and metastasis through the TLR4/NF-κB pathway in pancreatic carcinoma cells.

Molecular Pathways: Targeting B7-H3 (CD276) for Human Cancer Immunotherapy

B7-H3 (CD276) is an important immune checkpoint member of the B7 and CD28 families. Induced on antigen-presenting cells, B7-H3 plays an important role in the inhibition of T-cell function. Importantly, B7-H3 is highly overexpressed on a wide range of human solid cancers and often correlates with both negative prognosis and poor clinical outcome in patients. Challenges remain to identify the receptor(s) of B7-H3 and thus better elucidate the role of the B7-H3 pathway in immune responses and tumor evasion. With a preferential expression on tumor cells, B7-H3 is an attractive target for cancer immunotherapy. Based on the clinical success of inhibitory immune checkpoint blockade (CTLA-4, PD-1, and PD-L1), mAbs against B7-H3 appear to be a promising therapeutic strategy worthy of development. An unconventional mAb against B7-H3 with antibody-dependent cell-mediated cytotoxicity is currently being evaluated in a phase I clinical trial and has shown encouraging preliminary results. Additional therapeutic approaches in targeting B7-H3, such as blocking mAbs, bispecific mAbs, chimeric antigen receptor T cells, small-molecule inhibitors, and combination therapies, should be evaluated, as these technologies have already shown positive results in various cancer settings. A better understanding of the B7-H3 pathway in humans will surely help to further optimize associated cancer immunotherapies. Clin Cancer Res; 22(14); 3425-31. ©2016 AACR.

Expression of B7-H4 and hepatitis B virus X in hepatitis B virus-related hepatocellular carcinoma

AIM: To investigate the expression and clinical significance of B7-H4 and hepatitis B virus X (HBx) protein in hepatitis B virus-related hepatocellular carcinoma (HBV-HCC).

METHODS: The expression of B7-H4 in the human HCC cell lines HepG2 and HepG2.2.15 were detected by western blot, flow cytometry, and immunofluorescence. The expression of B7-H4 and HBx in 83 HBV-HCC was detected by immunohistochemistry, and the relationship with clinicopathological features was analyzed. Paraffin sections were generated from 83 HBV-HCC patients (22 females and 61 males) enrolled in this study. The age of these patients ranged from 35 to 77 years, with an average of 52.5 ± 11.3 years. All experiments were approved by the Ethics Committees of the Second Affiliated Hospital, Zhejiang University School of Medicine.

RESULTS: B7-H4 was significantly upregulated in HepG2.2.15 cells compared to HepG2 cells. Specifically, the protein expression of B7-H4 in the lysates of HepG2 cells was more than that in HepG2.2.15 cells. In addition, HBx was expressed only in HepG2.2.15 cells. Similar data were obtained by flow cytometry. The positive rates of B7-H4 and HBx in the tissues of 83 HBV-HCC patients were 68.67% (57/83) and 59.04% (49/83), respectively. The expression of HBx was correlated with tumor node metastases (TNM) stage, and the expression of B7-H4 was positively correlated with HBx (r_s = 0.388; P < 0.01). The expression level of B7-H4 in HBx-positive HBV-HCC tissues was substantially higher than that in HBx-negative HBV-HCC tissues. The expression level of B7H4 was negatively related to tumor TNM stage.

CONCLUSION: Higher expression of HBx and B7-H4 was correlated with tumor progression of HBV-HCC, suggesting that B7-H4 may be involved in facilitating HBV-related hepatocarcinogenesis.

PD-L1 (B7-H1) and PD-1 pathway blockade for cancer therapy: Mechanisms, response biomarkers, and combinations

PD-L1 and PD-1 (PD) pathway blockade is a highly promising therapy and has elicited durable antitumor responses and long-term remissions in a subset of patients with a broad spectrum of cancers. How to improve, widen, and predict the clinical response to anti-PD therapy is a central theme in the field of cancer immunology and immunotherapy. Oncologic, immunologic, genetic, and biological studies focused on the human cancer microenvironment have yielded substantial insight into this issue. Here, we focus on tumor microenvironment and evaluate several potential therapeutic response markers including the PD-L1 and PD-1 expression pattern, genetic mutations within cancer cells and neoantigens, cancer epigenetics and effector T cell landscape, and microbiota. We further clarify the mechanisms of action of these markers and their roles in shaping, being shaped, and/or predicting therapeutic responses. We also discuss a variety of combinations with PD pathway blockade and their scientific rationales for cancer treatment.

B7-H3, B7-H4, Foxp3 and IL-2 expression in cervical cancer: Associations with patient outcome and clinical significance

The aim of this study was to determine the expression of B7-H3, B7-H4, Foxp3 and IL-2 in cervical cancer tissues, and evaluate the corresponding clinical significance. The expression of B7-H3, B7-H4, Foxp3 and IL-2 in 108 cervical cancer specimens was detected using immunohistochemistry, and their relationship with clinicopathologic parameters was determined. B7-H3, B7-H4 and Foxp3 had high levels of expression in cervical cancer cells (72.22, 80.56, and 91.56%, respectively). B7-H3 levels were only significantly associated with tumor size (P=0.013), while B7-H4, Foxp3 and IL-2 levels were significantly associated with International Federation of Gynecology and Obstetrics (FIGO) stage (P=0.023, 0.014 and 0.036, respectively) and tumor size (P=0.045, 0.010 and 0.021, respectively). Their expression levels were not correlated with age, histologic type, differentiation and lymph node metastasis (all P>0.05). Cox regression multivariate analysis confirmed that B7-H3 or B7-H4 overexpression was an independent prognostic factor. In addition, there were significant positive relationships between the expression of B7-H3 and B7-H4 with Foxp3 (P<0.001). In contrast, the expression of B7-H3 and B7-H4 was negatively correlated with IL-2 (P<0.05). B7-H3, B7-H4 and Foxp3 may be useful biomarkers in patients with cervical cancer for predicting treatment.

PD-L1 expression in metastatic neuroblastoma as an additional mechanism for limiting immune surveillance

The prognosis of high-risk neuroblastoma (NB) remains poor, although immunotherapies with anti-GD2 antibodies have been reported to provide some benefit. Immunotherapies can be associated with an IFNγ storm that induces in tumor cells the "adaptive immune resistance" characterized by the de-novo expression of Programmed Death Ligands (PD-Ls). Tumor cells can also constitutively express PD-Ls in response to oncogenic signaling. Here, we analyze the constitutive and the inducible surface expression of PD-Ls in NB cells. We show that virtually all HLA class I^pos NB cell lines constitutively express PD-L1, whereas PD-L2 is rarely detected. IFNγ upregulates or induces PD-L1 both in NB cell lines in vitro and in NB engrafted nude/nude mice. Importantly, after IFNγ stimulation PD-L1 can be acquired by NB cell lines, as well as by metastatic neuroblasts isolated from bone marrow aspirates of high-risk NB patients, characterized by different MYCN amplification status. Interestingly, in one patient NB cells were poorly responsive to IFNγ stimulation, pointing out that responsiveness to IFNγ might represent a further element of heterogeneity in metastatic neuroblasts. Finally, we document the presence of lymphocytes expressing the PD-1 receptor in NB-infiltrated bone marrow of patients. PD-1^pos cells are mainly represented by αβ T cells, but also include small populations of γδ T cells and NK cells. Moreover, PD-1^pos T cells have a higher expression of activation markers. Overall, our data show that a PD-L1-mediated immune resistance mechanism occurs in metastatic neuroblasts and provide a biological rationale for blocking the PD-1/PD-Ls axis in future combined immunotherapeutic approaches.

B7-H3 silencing by RNAi inhibits tumor progression and enhances chemosensitivity in U937 cells

BACKGROUND

The role of B7-H3 in acute monocytic leukemia U937 cells has not been thoroughly investigated.

MATERIALS AND METHODS

B7-H3 knockdown in the U937 cell line was performed using small hairpin (sh)RNA lentivirus transduction. The effects on cell proliferation, cycle, migration, and invasion were investigated by Cell Counting Kit-8 assay, methyl cellulose colony-forming assay, propidium iodide staining, and Transwell assays in vitro. Changes in cell growth inhibition and apoptosis, when combined with chemotherapy drugs, were determined using the Cell Counting Kit-8 and Annexin V-FITC/PI assays. U937 xenograft models were used to assess the effects of B7-H3 on tumorigenicity and the therapeutic effect of B7-H3 knockdown in combination with chemotherapy drugs in vivo.

RESULTS

Downregulation of B7-H3 significantly decreased U937 cell growth and colony-forming ability. The mean inhibition rate of tumor growth with B7-H3 knockdown was 59.4%, and the expression of both Ki-67 and PCNA in xenografts was significantly reduced. After B7-H3 silencing, the U937 cell cycle was arrested at the G0/G1 phase. The cell migration rate of B7-H3 knockdown cells was reduced more than fivefold, and invasion capacity decreased by 86.7%. B7-H3 RNAi profoundly increased the antitumor effect of chemotherapy in vitro and in vivo. On day 19, inhibition rates of tumor growth in B7-H3 shRNA combined with idarubicin, cytarabine, and idarubicin plus cytarabine were 70.5%, 80.0%, and 90.0%, respectively (P=0.006, P=0.004, and P=0.016, respectively).

CONCLUSION

B7-H3 may promote U937 cell progression, and shRNA targeting B7-H3 significantly enhances sensitivity to chemotherapeutic drugs. These results may provide new insight into the function of B7-H3 and a promising therapeutic approach targeting B7-H3 in acute monocytic leukemia.

B7-H3 promotes aggression and invasion of hepatocellular carcinoma by targeting epithelial-to-mesenchymal transition via JAK2/STAT3/Slug signaling pathway

BACKGROUND

B7-homologue 3 (B7-H3), a recently identified immunoregulatory protein, has been shown to be overexpressed in human hepatocellular carcinoma (HCC). However, whether the dynamic expression pattern of B7-H3 contributes to early invasion of HCC is largely unknown. In addition, the biological roles of B7-H3 in HCC are still unclear. Herein, we are going to examine B7-H3 expression profile and its clinicopathological significance in primary and metastatic HCC, and further determine whether B7-H3 knockdown simulates different pathological states of HCC progression and metastasis.

METHODS

Using immunohistochemistry, B7-H3 expression was studied on 116 HCC containing primary and metastatic HCCs. Survival curves and log-rank tests were used to test the association of B7-H3 expression with survival. HCC cells with B7-H3 depletion were established by RNA interference to investigate the effect of B7-H3 on cell proliferation, apoptosis, migration and invasion in vitro.

RESULTS

Statistical analysis of clinical cases revealed that B7-H3 high expression group had inclinations towards late TNM stage, the presence of vascular invasion, lymph metastasis, and the formation of microsatellite tumors. Increased intensity of tumor B7-H3 staining was detected more significantly in metastatic HCC tumors. Consistently in experiments performed in vitro, B7-H3 was able to stimulate the wound healing, metastasis and invasion of hepatoma cells by targeting epithelial-to-mesenchymal transition (EMT) via JAK2/Stat3/Slug signaling pathway, while no obvious influence on cell growth and apoptosis.

CONCLUSION

B7-H3 in the regulation of the metastatic capacity of HCC cells makes itself a promising therapeutic target for anti-metastasis therapy.

B7-H3 silencing inhibits tumor progression of mantle cell lymphoma and enhances chemosensitivity

B7-H3 (CD276), known as a member of B7 immunoregulatory family, is a type I transmembrane glycoprotein aberrantly expressed in numerous types of cancer and associated with poor prognosis. However, the role of B7-H3 in oncogenesis and chemosensitivity of mantle cell lymphoma (MCL) remains unknown. We determined the effects of downregulating B7-H3 expression on tumor progression and the sensitivity of chemotherapeutic drug in mantle cell lymphoma. B7-H3 knockdown was performed using lentivirus transduction in the Maver and Z138 mantle cell lymphoma cell lines, respectively. The effects of B7-H3 on cell proliferation, cycle, migration and invasion were investigated by CCK-8 assay, methyl cellulose colony forming assay, PI staining, and Transwell assays in vitro. By establishing Maver and Z138 xenograft models, the effects of B7-H3 on tumorigenicity were observed, and Ki-67 and PCNA was detected by immunohistochemistry. The downregulation of B7-H3 significantly decreased tumor proliferation in MCL in vitro and in vivo. In the B7-H3 knockdown groups of Maver and Z138 xenograft models, the mean inhibition rate of tumor growth was 59.1 and 65.0% (p=0.010 and 0.003), and the expression of both Ki-67 and PCNA were significantly lower, respectively. After B7-H3 silencing, the cell cycles of Maver and Z138 were both arrested at G0/G1 phase, and the cell migration rates and invasion capacity were decreased as well. Moreover, the impacts of B7-H3 RNAi on the antitumor effect of chemotherapy drugs were determined with CCK-8 and Annexin V-FITC/PI assays in vitro and with xenograft models in vivo. The silencing of B7-H3 increased the sensitivity of Maver and Z138 cells to rituximab and bendamustine and enhanced the drug-induced apoptosis, respectively. Our study demonstrates for the first time that B7-H3 promotes mantle cell lymphoma progression and B7-H3 knockdown significantly enhances the chemosensitivity. This may provide a new therapeutic approach to mantle cell lymphoma.

T cells and costimulation in cancer

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

B7-H3 expression in colorectal cancer: associations with clinicopathological parameters and patient outcome

Background

We have previously reported overexpression of the immunoregulatory protein B7-H3 in colorectal cancer and that nuclear expression predicted poor outcome in colon cancer patients. The present study was performed to examine the prognostic role of B7-H3 in an independent colorectal cancer cohort.

Methods

Using tissue microarrays from 731 colorectal cancer patients, tumour B7-H3 expression was assessed by immunohistochemistry. Associations with clinicopathological parameters and patient outcome were investigated.

Results

Nuclear expression of B7-H3 in cancer cells was present in 27% of the samples in the total study cohort, while cytoplasmic/membrane and stromal expression was seen in 86% and 77% of the samples, respectively. Nuclear B7-H3 had no prognostic relevance in the complete outcome cohort, neither in colon cancer patients. However, nuclear B7-H3 was significantly associated with reduced recurrence-free survival in TNM stage I colorectal cancer patients.

Conclusions

Overexpression of B7-H3 in colorectal cancer was confirmed, but in contrast to previous results, nuclear B7-H3 was not a strong prognostic biomarker in this cohort. The discrepancy might be related to the use of single-core tissue microarrays for detection of the heterogeneously expressed B7-H3, and the role of B7-H3 in colorectal cancer still needs further examination.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-602) contains supplementary material, which is available to authorized users.

Identifying microRNAs regulating B7-H3 in breast cancer: the clinical impact of microRNA-29c

Background:

B7-H3, an immunoregulatory protein, is overexpressed in several cancers and is often associated with metastasis and poor prognosis. Here, our aim was to identify microRNAs (miRNAs) regulating B7-H3 and assess their potential prognostic implications in breast cancer.

Methods:

MicroRNAs targeting B7-H3 were identified by transfecting two breast cancer cell lines with a library of 810 miRNA mimics and quantifying changes of B7-H3 protein levels using protein lysate microarrays. For validations we used western immunoblotting and 3′-UTR luciferase assays. Clinical significance of the miRNAs was assayed by analysing whether their expression levels correlated with outcome in two cohorts of breast cancer patients (142 and 81 patients).

Results:

We identified nearly 50 miRNAs that downregulated B7-H3 protein levels. Western immunoblotting validated the impact of the 20 most effective miRNAs. Thirteen miRNAs (miR-214, miR-363*, miR-326, miR-940, miR-29c, miR-665, miR-34b*, miR-708, miR-601, miR-124a, miR-380-5p, miR-885-3p, and miR-593) targeted B7-H3 directly by binding to its 3′-UTR region. Finally, high expression of miR-29c was associated with a significant reduced risk of dying from breast cancer in both cohorts.

Conclusions:

We identified miRNAs efficiently downregulating B7-H3 expression. The expression of miR-29c correlated with survival in breast cancer patients, suggesting a tumour suppressive role for this miRNA.

Natural killer cells and neuroblastoma: tumor recognition, escape mechanisms, and possible novel immunotherapeutic approaches

Neuroblastoma (NB) is the most common extra-cranial solid tumor of childhood and arises from developing sympathetic nervous system. Most primary tumors localize in the abdomen, the adrenal gland, or lumbar sympathetic ganglia. Amplification in tumor cells of MYCN, the major oncogenic driver, patients' age over 18 months, and the presence at diagnosis of a metastatic disease (stage IV, M) identify NB at high risk of treatment failure. Conventional therapies did not significantly improve the overall survival of these patients. Moreover, the limited landscape of somatic mutations detected in NB is hampering the development of novel pharmacological approaches. Major efforts aim to identify novel NB-associated surface molecules that activate immune responses and/or direct drugs to tumor cells and tumor-associated vessels. PVR (Poliovirus Receptor) and B7-H3 are promising targets, since they are expressed by most high-risk NB, are upregulated in tumor vasculature and are essential for tumor survival/invasiveness. PVR is a ligand of DNAM-1 activating receptor that triggers the cytolytic activity of natural killer (NK) cells against NB. In animal models, targeting of PVR with an attenuated oncolytic poliovirus induced tumor regression and elimination. Also B7-H3 was successfully targeted in preclinical studies and is now being tested in phase I/II clinical trials. B7-H3 down-regulates NK cytotoxicity, providing NB with a mechanism of escape from immune response. The immunosuppressive potential of NB can be enhanced by the release of soluble factors that impair NK cell function and/or recruitment. Among these, TGF-β1 modulates the cytotoxicity receptors and the chemokine receptor repertoire of NK cells. Here, we summarize the current knowledge on the main cell surface molecules and soluble mediators that modulate the function of NK cells in NB, considering the pros and cons that must be taken into account in the design of novel NK cell-based immunotherapeutic approaches.

B7-H3 is overexpressed in patients suffering osteosarcoma and associated with tumor aggressiveness and metastasis

B7-H3 is a member of the B7-family of co-stimulatory molecules, which has been shown to be broadly expressed in various tumor tissues, and which plays an important role in adaptive immune responses. The role of B7-H3 in osteosarcoma, however, remains unknown. In this study we used immunohistochemistry to analyze B7-H3 expression in 61 primary osteosarcoma tissues with case-matched adjacent normal tissues, and 37 osteochondroma and 20 bone fibrous dysplasia tissues. B7-H3 expression was expressed in 91.8% (56/61) of the osteosarcoma lesions, and the intensity of B7-H3 expression in osteosarcoma was significantly increased compared with adjacent normal tissues, osteochondroma and bone fibrous dysplasia tissues (p<0.001). Patients with high tumor B7-H3 levels had a significantly shorter survival time and recurrence time than patients with low tumor B7-H3 levels (p<0.001). Moreover, tumor B7-H3 expression inversely correlated with the number of tumor-infiltrating CD8⁺ T cells (p<0.05). In vitro, increasing expression of B7-H3 promotes osteosarcoma cell invasion, at least in part by upregulating matrix metalloproteinase-2 (MMP-2). In conclusion, our study provides the first evidence of B7-H3 expression in osteosarcoma cells as a potential mechanism controlling tumor immunity and invasive malignancy, and which is correlated with patients’ survival and metastasis.