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

BACKGROUND: Despite advances in B7 homolog 3 protein (B7-H3) based immunotherapy, the development of drug resistance remains a major clinical concern. The heterogeneity and emerging loss of B7-H3 expression are the main causes of drug resistance and treatment failure in targeted therapies, which reveals an urgent need to elucidate the mechanism underlying the regulation of B7-H3 expression. In this study, we identified and explored the crucial role of the transcription factor SPT20 homolog (SP20H) in B7-H3 expression and tumor progression. METHODS: Here, we performed CRISPR/Cas9-based genome scale loss-of-function screening to identify regulators of B7-H3 in human ovarian cancer cells. Signaling pathways altered by SP20H knockout were revealed by RNA sequencing. The regulatory role and mechanism of SP20H in B7-H3 expression were validated using loss-of-function and gain-of-function assays in vitro. The effects of inhibiting SP20H on tumor growth and efficacy of anti-B7-H3 treatment were evaluated in tumor-bearing mice. RESULTS: We identified SUPT20H (SP20H) as negative and eIF4E as positive regulators of B7-H3 expression in various cancer cells. Furthermore, we provided evidence that either SP20H loss or TNF-α stimulation in tumor cells constitutively activates p38 MAPK-eIF4E signaling, thereby upregulating B7-H3 expression. Loss of SP20H upregulated B7-H3 expression both in vitro and in vivo. Additionally, deletion of SP20H significantly suppressed tumor growth and increased immune cells infiltration in tumor microenvironment. More importantly, antibody-drug conjugates targeting B7-H3 exhibited superior antitumor performance against SP20H-deficient tumors relative to control groups. CONCLUSIONS: Activation of p38 MAPK-eIF4E signaling serves as a key event in the transcription initiation and B7-H3 protein expression in tumor cells. Genetically targeting SP20H upregulates target antigen expression and sensitizes tumors to anti-B7-H3 treatment. Collectively, our findings provide new insight into the mechanisms underlying B7-H3 expression and introduce a potential synergistic target for existing antibody-based targeted therapy against B7-H3.

Multi-Omics Data Analyses Identify B7-H3 as a Novel Prognostic Biomarker and Predict Response to Immune Checkpoint Blockade in Head and Neck Squamous Cell Carcinoma.

B7 homolog 3 (B7-H3) is a recently found superfamily B7 molecule and therefore has significant involvement in immunological regulation. However, the relationships of B7-H3 expression with the tumor microenvironment (TME), response to immunotherapy, and prognosis in head and neck squamous cell carcinoma (HNSCC) are still unknown. In the present analysis, we determined B7-H3 as a novel biomarker that predicts the prognosis and response to immunotherapy in HNSCC. B7-H3 expression is enhanced in HNSCC compared to normal sample and is stably expressed in HNSCC cell line. Besides, high B7-H3 expression is correlated with a dismal prognosis and resistance to immunotherapy and contributes to an immunosuppressive microenvironment. Moreover, single-cell RNA sequencing (scRNA-seq) analysis shows that B7-H3 is mainly expressed in the stromal as well as malignant cells. In conclusion, the study provides insight in understanding the prognostic value of B7-H3 in HNSCC and highlights its involvement in promoting the immunosuppressive microenvironment, which presents an attractive strategy for antibody-based immunotherapy.

Mifepristone inhibited the expression of B7-H2, B7-H3, B7-H4 and PD-L2 in adenomyosis.

BACKGROUND: The immune mechanism was shown to be involved in the development of adenomyosis. The aim of the current study was to evaluate the expression of the immune checkpoints B7-H2, B7-H3, B7-H4 and PD-L2 in adenomyosis and to explore the effect of mifepristone on the expression of these immune checkpoints. METHODS: The expression of B7-H2, B7-H3, B7-H4 and PD-L2 in normal endometria and adenomyosis patient samples treated with or without mifepristone was determined by immunohistochemistry analysis. RESULTS: In adenomyosis patient samples, the expression of B7-H2, B7-H3 and B7-H4 was increased in the eutopic and ectopic endometria compared with normal endometria, both in the proliferative and secretory phases. Moreover, the expression of B7-H2 and B7-H3 was higher in adenomyotic lesions than in the corresponding eutopic endometria, both in the proliferative and secretory phases. The expression of PD-L2 was higher in adenomyotic lesions than in normal endometria in both the proliferative and secretory phases. In the secretory phase but not the proliferative phase, the expression of B7-H4 and PD-L2 in adenomyotic lesions was significantly higher than that in the corresponding eutopic endometria. In normal endometria and eutopic endometria, the expression of B7-H4 was elevated in the proliferative phase compared with that in the secretory phase, while in the ectopic endometria, B7-H4 expression was decreased in the proliferative phase compared with the secretory phase. In addition, the expression of B7-H2, B7-H3, B7-H4 and PD-L2 was significantly decreased in adenomyosis tissues after treatment with mifepristone. CONCLUSIONS: The expression of the immune checkpoint proteins B7-H2, B7-H3, B7-H4 and PD-L2 is upregulated in adenomyosis tissues and is downregulated with mifepristone treatment. The data suggest that B7 immunomodulatory molecules are involved in the pathophysiology of adenomyosis.

Immune checkpoint B7-H3 protein expression is associated with poor outcome and androgen receptor status in prostate cancer.

BACKGROUND: Novel immune checkpoint-based immunotherapies may benefit specific groups of prostate cancer patients who are resistant to other treatments. METHODS: We analyzed by immunohistochemistry the expression of B7-H3, PD-L1/B7-H1, and androgen receptor (AR) in tissue samples from 120 prostate adenocarcinoma patients treated with radical prostatectomy in Spain, and from 206 prostate adenocarcinoma patients treated with radical prostatectomy in Norway. RESULTS: B7-H3 expression correlated positively with AR expression and was associated with biochemical recurrence in the Spanish cohort, but PD-L1 expression correlated with neither of them. Findings for B7-H3 were validated in the Norwegian cohort, where B7-H3 expression correlated positively with Gleason grade, surgical margins, seminal vesicle invasion, and CAPRA-S risk group, and was associated with clinical recurrence. High B7-H3 expression in the Norwegian cohort was also consistent with positive AR expression. CONCLUSION: These results suggest distinct clinical relevance of the two immune checkpoint proteins PD-L1 and B7-H3 in prostate cancer. Our findings highlight B7-H3 as an actionable novel immune checkpoint protein in prostate cancer.

MiR-29c downregulates tumor-expressed B7-H3 to mediate the antitumor NK-cell functions in ovarian cancer.

OBJECTIVE: B7-H3 is a member of the B7 family of immune checkpoint molecule. Although B7-H3 has been shown to regulate T cell-mediated peripheral immune response, whether it also correlated with NK cell exhaustion in ovarian cancer remains unclear. The purpose of this study was to explore the mechanism of B7-H3 regulating NK-cell proliferation and function. MATERIAL AND METHODS: To investigate the relationship between B7-H3 expression and the NK-cell function in ovarian cancer, human ovarian tumor tissues and cell lines were first examined the protein and mRNA expression of B7-H3 by quantitative real-time PCR (qRT-PCR), Immunohistochemistry and Western-blot assays. Then we established B7-H3 knockout cell lines and measured the cytotoxicity of NK cells on these cells by LDH release assay and Flow Cytometry. In addition, we analyzed B7-H3 in the regulation of glycolysis and glycolysis-related proteins by Glycolysis Stress Test, Glucose Consumption Assay and Western-blot. Moreover, luciferase reporter assay was used to confirm the directly regulation of miR-29c to B7-H3. Finally, we carried out in vivo experiments. RESULTS: We observed that tumor-expressed B7-H3 inhibits NK-cell function in vitro and in vivo, and is associated with glycolysis of ovarian cancer cell. Therapeutically, B7-H3 blockade prolonged the survival of SKOV3 tumor-bearing mice. In addition, miR-29c improved the anti-tumor efficacy of NK-cell by directly targeting B7-H3 in vitro were observed, but not in vivo. CONCLUSION: Our results demonstrate that miR-29c downregulates B7-H3 to inhibit NK-cell exhaustion and associated with glycolysis, which suggest that NK cells may be a new target of anti-B7-H3 therapy in ovarian cancer patients.

Canine osteosarcoma checkpoint expression correlates with metastasis and T-cell infiltrate.

BACKGROUND: Immune-targeted therapies are being successfully implemented into cancer clinical practice. In particular checkpoint inhibitors are employed to modulate the immune microenvironment of solid tumors. We sought to determine the expression of PD-L1, HVEM, and B7H3 in human and canine osteosarcoma, and correlate expression with clinical features and tumor infiltrating lymphocytes in naturally-occurring canine osteosarcoma. METHODS: Flow cytometry was used to measure ligand surface expression of five human and three canine cell lines. Immunohistochemistry was utilized for expression of ligands and lymphocyte markers in thirty-seven treatment-naïve canine osteosarcoma patients. RESULTS: All cell lines expressed all three ligands at variable levels in both species. Metastatic lesions were associated with higher expression of all three ligands in patient tumor samples. PD-L1 expression strongly correlated with B7H3 and HVEM expression, while HVEM and B7H3 were weakly correlated. Whereas peritumoral T-cell expression positively correlated with PD-L1 and HVEM tumor expression, the presence of T-cells intratumorally were rare. Furthermore, intratumor penetration by T-cells was greatest in metastatic lesions, despite log-fold increases in peritumoral T-cells. In summary, PD-L1, HVEM, and B7H3 are expressed in osteosarcoma, with metastatic disease lesions expressing higher levels. We show for the first time that these ligands expressed on osteosarcoma cells positively correlate with each other and the presence of peritumoral T cell infiltration. Furthermore, osteosarcoma appears to be an intratumoral immune desert with significant resistance to effector T cells. Multiple agents targeting checkpoints are in clinical practice, and may have immune modulating benefit in osteosarcoma.

B7-H3 is spliced by SRSF3 in colorectal cancer.

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

B7-H3 augments the pro-angiogenic function of tumor-associated macrophages and acts as a novel adjuvant target for triple-negative breast cancer therapy.

B7-H3 is an immune checkpoint molecule from the B7 superfamily. It has been widely studied in tumor immune evasion in certain types of cancer. In our preliminary study, we found that B7-H3 is specifically enriched in tumor-associated macrophages (TAMs) in triple-negative breast cancer (TNBC) patients and strongly correlated with poor clinical prognosis. However, the role of B7-H3 in breast cancer remains elusive. Our current study aims to explore the potential of B7-H3 as a novel target in TNBC therapy. Here, we demonstrated that B7-H3 enriched on TAMs is tightly correlated with TNBC clinical progression. B7-H3high TAMs exhibit great pro-metastatic and immunosuppressive functions by intriguing extracellular matrix (ECM) reconstruction and tumor angiogenesis, therefore helping tumor cell dissemination and dampening T-cell infiltration in tumor microenvironment (TME). Importantly, targeting blockade of B7-H3 by anti-B7-H3 antibody improves the tumor vasculature disorder, thereby enhancing chemotherapy and PD-1 therapy efficacy. In conclusion, our study establishes the correlation between B7-H3high TAMs and TNBC progression for the first time. By exploring the possibility of targeting B7-H3 expressed in both tumor cells and TAMs, we suggest that B7-H3 could be a promising target in clinical TNBC treatment.

The expression and clinical significance of B7-H3 and miR-145 in lung cancer patients with malignant pleural effusion.

OBJECTIVE: To investigate the expression and clinical significance of costimulatory molecule B7-H3 and microRNA-145 (miR-145) in lung cancer patients with malignant pleural effusion. PATIENTS AND METHODS: A total of 100 cases of patients with lung cancer who admitted to our hospital for treatment from March 2017 to September 2018 were selected. Forty-nine cases of patients diagnosed with malignant pleural effusion were included in the study group, and 51 cases with benign pleural effusion in the control group. The content of B7-H3 in pleural effusion of the two groups was detected by enzyme-linked immunosorbent assay (ELISA), and the expression of miR-145 in pleural effusion of the two groups was analyzed by Real-time quantitative PCR (qRT-PCR). The relationships between the expressions of B7-H3 and miR-145 and the clinicopathological characteristics were analyzed. The diagnostic value of B7-H3 and miR-145 in lung cancer was analyzed. RESULTS: The expression level of B7-H3 in the study group was significantly higher than that in the control group (p<0.050), while the expression level of miR-145 was significantly lower than that in the control group (p<0.050). The expression levels of B7-H3 and miR-145 in the study group were correlated with lymph node metastasis, differentiation degree of lung cancer and TNM stage (p<0.001). The sensitivity and specificity of miR-145 in single diagnosis of lung cancer were 64.71% and 79.59%, respectively. The sensitivity and specificity of B7-H3 in single diagnosis of lung cancer were 80.39% and 61.22%, respectively. CONCLUSIONS: B7-H3 and miR-145 are abnormally expressed in lung cancer, and are closely related to the lymphatic metastasis, differentiation degree and TNM stage of lung cancer. They may be potential markers for the diagnosis of malignant pleural effusion in lung cancer in the future.

Cytoplasmic expression of B7-H3 and membranous EpCAM expression are associated with higher grade and survival outcomes in patients with clear cell renal cell carcinoma.

B7-H3 and EpCAM are overexpressed in cancer and play a role in tumorigenesis and metastasis. In this study, the membranous, cytoplasmic and nuclear expression levels of B7-H3 and EpCAM biomarkers were mapped in three major subtypes of renal cell carcinoma (RCC). Expression of B7-H3 and EpCAM were evaluated using immunohistochemistry in RCC samples on tissue microarrays (TMAs), including clear cell RCCs (ccRCCs), type I and II papillary RCCs (pRCCs), and chromophobe RCCs (chRCCs). The association between B7-H3 and EpCAM expression and clinicopathological features as well as survival outcomes was determined. There was a statistically significant difference between B7-H3 and EpCAM expression among the different RCC subtypes. In ccRCC, higher cytoplasmic expression of B7-H3 was significantly associated with increase in nucleolar grade, lymph node invasion (LNI), invasion of the Gerota's fascia, and tumor necrosis, while no association was found with the membranous and nuclear expression. Moreover tumors with cytoplasmic expression of B7-H3 tended to have a worse prognosis for disease-specific survival (DSS) than those with membranous expression. In case of EpCAM, increased membranous expression of EpCAM was associated with nucleolar grade and tumor necrosis in ccRCC. Additionally, membranous EpCAM expression added prognostic value in patients with ccRCC who had high nucleolar grade versus low nucleolar grade. Moreover, membranous EpCAM expression was found to be an independent favorable prognostic marker for progression-free survival (PFS) in ccRCC. Our results demonstrated that higher cytoplasmic B7-H3 and membranous EpCAM expression are clinically significant in ccRCC and are associated with more aggressiveness tumor behavior.

FOXD3 Regulates VISTA Expression in Melanoma.

Immune checkpoint inhibitors have improved patient survival in melanoma, but the innate resistance of many patients necessitates the investigation of alternative immune targets. Many immune checkpoint proteins lack proper characterization, including V-domain Ig suppressor of T cell activation (VISTA). VISTA expression on immune cells can suppress T cell activity; however, few studies have investigated its expression and regulation in cancer cells. In this study, we observe that VISTA is expressed in melanoma patient samples and cell lines. Tumor cell-specific expression of VISTA promotes tumor onset in vivo, associated with increased intratumoral T regulatory cells, and enhanced PDL-1 expression on tumor-infiltrating macrophages. VISTA transcript levels are regulated by the stemness factor Forkhead box D3 (FOXD3). BRAF inhibition upregulates FOXD3 and reduces VISTA expression. Overall, this study demonstrates melanoma cell expression of VISTA and its regulation by FOXD3, contributing to the rationale for therapeutic strategies that combine targeted inhibitors with immune checkpoint blockade.

CD276 and the gene signature composed of GATA3 and LGALS3 enable prognosis prediction of glioblastoma multiforme.

Glioma is the most common type of primary brain tumor, accounting for 40% of malignant brain tumors. Although a single gene may not be a marker, an expression profiling and multivariate analyses for cancer immunotherapy must estimate survival of patients. In this study, we conducted expression profiling of immunotherapy-related genes, including those in Th1/2 helper T and regulatory T cells, and stimulatory and inhibitory checkpoint molecules associated with survival prediction in 571 patients with malignant and aggressive form of gliomas, glioblastoma multiforme (GBM). Expression profiling and Random forests analysis of 21 immunosuppressive genes and Kaplan-Meier analysis in 158 patients in the training data set suggested that CD276, also known as B7-H3, could be a single gene marker candidate. Furthermore, prognosis prediction formulas, composed of Th2 cell-related GATA transcription factor 3 (GATA3) and immunosuppressive galactose-specific lectin 3 (LGALS3), based on 67 immunotherapy-related genes showed poor survival with high scores in training data set, which was also validated in another 413 patients in the test data set. The CD276 expression helped distinguish survival curves in the test data set. In addition, inhibitory checkpoint genes, including T cell immunoreceptor with Ig and ITIM domains, V-set domain containing T cell activation inhibitor 1, T-cell immunoglobulin and mucin-domain containing 3, and tumor necrosis factor receptor superfamily 14, showed potential as secondary marker candidates. These results suggest that CD276 expression and the gene signature composed of GATA3 and LGALS3 are effective for prognosis in GBM and will help us understanding target pathways for immunotherapy in GBM.

PD-L1, B7-H3 and VISTA are highly expressed in gestational trophoblastic neoplasia.

AIMS: The B7 family check-point molecules are potential therapeutic targets in cancer immunotherapy. However, their expression status in human gestational trophoblastic neoplasia (GTN) remains unknown. We investigated the expression profiles of the B7 family check-point proteins PD-L1, PD-L2, B7-H3, B7-H4, VISTA and B7-H6 in GTN and their clinical significance. METHODS AND RESULTS: We identified 112 patients with GTN, including 68 with choriocarcinoma, 33 with placental-site trophoblastic tumour (PSTT) and 11 with epithelioid trophoblastic tumour (ETT). Immunohistochemical staining was performed on whole-tissue GTN sections using anti-B7 family antibodies. VISTA expression was immunohistochemically analysed using microarrays of normal human tissues and of 20 common cancers. PD-L1 and B7-H3 were highly expressed in all GTN tumours, while PD-L2 was expressed in 87.5% of the samples. B7-H4 and B7-H6 were negative in 100% and 98.2% of the samples, respectively. PD-L1, B7-H3 and VISTA levels were significantly higher in choriocarcinomas and PSTTs than in ETTs. There was no association between B7 family check-point expression in tumour cells and disease stage, prognostic score or patient outcomes (complete remission versus death). VISTA protein was widely overexpressed in 98.2% of all the GTN, but its expression varied in other cancer types and was negative in normal adult and fetal tissues except placental trophoblasts and splenic lymphocytes. CONCLUSIONS: The GTN trophoblast cells show high expression of PD-L1, B7-H3 and VISTA in a manner that is independent of clinical outcomes. These proteins may be potential immunotherapeutic targets when treating GTN.

Effects of liver-targeted drugs on expression of immune-related proteins in hepatocellular carcinoma cells.

BACKGROUND: The molecular mechanisms involved in the development and metastasis of hepatocellular carcinoma (HCC) are complex. Molecule-targeted drugs are characterized by strong specificity and low toxicity, but the clinical research of these drugs still exhibits many difficulties, such as poor target specificity. With the in-depth study of the tumor immunological theory, therapies based on overcoming the tumor immune escape to produce a specific effective tumor immune response has gradually become a hot topic in tumor research. We hope that by studying the effects of liver-targeted drugs on the expression of immune-related proteins in hepatocellular carcinoma cells, we will find a potential link to further guide the clinical drug use. METHODS: Human hepatoma Hep3B cells were used to establish liver cancer xenografts by inoculating 40 BALB/c nude mice. The following five groups of mice (8 mice per group) were randomly set up: lenvatinib group, apatinib group, sorafenib group, regorafenib group, and dimethyl sulfoxide (DMSO) group. After treatment, we analyzed PD-L1 and B7-H3 mRNA using the real-time polymerase chain reaction (PCR) assay and assessed the PD-L1 and B7-H3 protein expression by Western immunoblotting. RESULTS: Real-time PCR results suggested that the mRNA expression of PD-L1 in the lenvatinib group was significantly higher than that in the control group, while its expression in the regorafenib group was significantly lower than that in the control group (both p < .05). Western immunoblotting results suggested that, compared with the control group, PD-L1 protein was increased in the lenvatinib group, while its expression in the regorafenib group was decreased. CONCLUSION: Lenvatinib and regorafenib affected the expression of PD-L1 in the process of anti-HCC.

Correlation of IDH1 and B7H3 expression with prognosis of CRC patients.

BACKGROUND: B7H3 is an immuno-stimulatory glycoprotein that is overexpressed in cancer. However, its functional contributions to cancer development and progression are not well understood. In several reports, it was demonstrated that B7H3 reprograms lipid metabolism and regulates glucose metabolism. Isocitrate dehydrogenase 1 (IDH1), a metabolic enzyme in the TCA cycle, its reaction product is involved in lipid synthesis. Thus, we aimed to identify a novel marker to predict the prognosis of CRC patients and to investigate the relationship between IDH1 and B7H3. METHODS: We analyzed IDH1 and B7H3 expression levels in 225 CRC specimens by immunochemistry. Moreover, in vitro studies were performed to demonstrate the correlation between IDH1 and B7H3. RESULTS: Among 225 tissues, the positive rates of IDH1 and B7H3 were 37.8% (85/225) and 87.6% (197/225), respectively. In CRC samples, IDH1 significantly correlated with B7H3 expression (P = 0.044). Moreover, multivariate analyses revealed that high expression of both B7H3 and IDH1 and a high tumor grade were related to the prognosis of CRC patients. Kaplan-Meier survival analysis revealed that patients with co-expression of IDH1 and B7H3 had a poor overall survival. In SW480B7H3-EGFP cells, which highly express B7H3, IDH1 was up-regulated. Similarly, knockdown of B7H3 expression in Caco-2-shB7-H3 contributed to reduced IDH1 levels. CONCLUSIONS: Although IDH1 and B7H3 cannot be used as independent prognostic factors, co-expression of IDH1 and B7H3 significantly correlated with the prognosis of CRC patients and may serve as a combined predictive marker. Thus, the correlation between IDH1 and B7H3 has been proven in vivo and in vitro.

High-Density Infiltration of V-domain Immunoglobulin Suppressor of T-cell Activation Up-regulated Immune Cells in Human Pancreatic Cancer.

V-domain immunoglobulin suppressor of T-cell activation (VISTA) is constitutively expressed in hematopoietic lineage and is highly up-regulated in tumor infiltrated myeloid cells and regulatory T-cells in animal models. However, its expression in human pancreatic tumor microenvironment remains unknown. In this research, we aimed at the expression of VISTA in human pancreatic cancer samples. METHODS: We performed immunohistochemistry to determine VISTA expression in human pancreatic cancer samples. RESULTS: We found that 88.46% of the patients showed high-density infiltration of polymorphonuclear neutrophils and mononuclear immune cells with up-regulated expression of VISTA in cancer tissues, especially in the necrotic foci. Interestingly, it was minimally expressed in pancreatic cancerous cells and was not detectable in either normal ducts or islet cells in cancerous or normal pancreatic tissues. CONCLUSIONS: We conclude that VISTA is predominantly expressed and up-regulated in the high-density infiltrated immune cells but minimal in human pancreatic cancerous cells. Our results for the first time highlight pancreatic immunosuppressive tumor microenvironment contributed by VISTA and its potential as a prominent target for pancreatic cancer immunotherapy.

VISTA expression associated with CD8 confers a favorable immune microenvironment and better overall survival in hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) often arises in the setting of chronic inflammation with multiple inhibitory immune signals. V-domain Ig suppressor of T cell activation (VISTA) is identified as a novel negative checkpoint regulator. This study sought to determine the expression and prognostic value of VISTA in HCC and classify tumor microenvironments (TMEs) based on VISTA and CD8+ tumor-infiltrating lymphocytes (TILs). METHODS: The expression of VISTA and CD8 proteins was assessed in 183 HCC tissue microarrays (TMAs) by immunohistochemistry (IHC). VISTA and CD8A mRNA extracted from 372 patients with HCC in The Cancer Genome Atlas (TCGA) database was included as a validation cohort. Associations between the VISTA, clinicopathological variables, and survival were analyzed. RESULTS: VISTA expression was detected in 29.5% HCC tissues, among which 16.4% tissues were positive for tumor cells (TCs), and 16.9% tissues were positive for immune cells (ICs). VISTA expression was significantly associated with tissues with a high pathological grading (p = 0.038), without liver cirrhosis (p = 0.011), and with a high density of CD8 + TILs (p < 0.001). Kaplan-Meier curves demonstrated that patients with VISTA-positive staining in TCs (p = 0.037), but not in ICs, (p = 0.779) showed significantly prolonged overall survival (OS) than those with VISTA-negative expression. Classification of HCC TME-based VISTA and CD8 + TILs showed 4 immune subtypes: VISTA+/CD8+ (16.9%), VISTA+/CD8- (12.6%), VISTA-/CD8+ (16.4%), and VISTA-/CD8+ (54.1%). The dual positive VISTA+/CD8+ subtype showed significantly prolonged OS than other subtypes (p = 0.023). CONCLUSIONS: VISTA protein expression in HCC showed cell specific and displayed different prognosis. VISTA expression was significantly associated with CD8 + TILs, Dual positive VISTA+/CD8+ showed favorable TME and better OS.

The prognostic value of B7-H6 protein expression in human oral squamous cell carcinoma.

OBJECTIVES: To investigate the expression and prognostic value of B7-H6 protein in oral squamous cell carcinoma tissues. MATERIALS AND METHODS: A total of 50 oral squamous cell carcinoma samples, 10 oral leukoplakia (OLK) samples, and 17 normal controls were included in the analysis. The expression of B7-H6 in oral squamous cell carcinoma, OLK, and normal controls was evaluated by immunohistochemical assay. RESULTS: The B7-H6 protein expression was significantly higher in oral squamous cell carcinoma tissues than that in normal oral mucosa. Furthermore, a significant relationship was found between the expression of B7-H6 and differentiation, but not with age, sex, tumor size, lymph metastasis, clinical stage, or recurrence. Further, the survival curves showed that B7-H6 was an independent prognostic factor of overall survival and disease-free survival in oral squamous cell carcinoma. Moreover, multivariate survival analysis by COX proportional hazard regression model revealed that the recurrence, differentiation, and expression of B7-H6 were related to the prognosis. Lastly, we verified the prognostic value of B7-H6 in oral squamous cell carcinoma. CONCLUSIONS: B7-H6 may represent a new prognostic marker for oral squamous cell carcinoma.

Expression of VISTA correlated with immunosuppression and synergized with CD8 to predict survival in human oral squamous cell carcinoma.

V-domain Ig suppressor of T cell activation (VISTA), a novel immune checkpoint regulatory molecule, suppresses T cell mediated immune responses. The aim of the present study was to profile the immunological expression, clinical significance and correlation of VISTA in human oral squamous cell carcinoma (OSCC). Human tissue microarrays, containing 165 primary OSCCs, 48 oral epithelial dysplasias and 43 normal oral mucosae, were applied to investigate the expression levels of VISTA, CD8, cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), programmed death ligand 1 (PD-L1), PI3Kα p110, IL13Rα2, phospho-STAT3 at tyrosine 705 (p-STAT3) and myeloid-derived suppressor cell (MDSC) markers (CD11b and CD33) by immunohistochemistry and digital pathology analysis. The results demonstrated that the protein level of VISTA was significantly higher in human OSCC specimens, and that VISTA expression in primary OSCCs was correlated with lymph node status. VISTA expression did not serve as an independent predictor for poor prognosis, while patient subgroup with VISTA high and CD8 low expression (22/165) had significantly poorer overall survival compared with other subgroups based on the multivariate and Cox hazard analyses among the primary OSCC patients in the present cohort. Additionally, the expression of VISTA was significantly correlated with PD-L1, CTLA-4, IL13Rα2, PI3K, p-STAT3, CD11b and CD33 according to Pearson's correlation coefficient test. Taken together, the results indicated that the VISTA high and CD8 low group, as an immunosuppressive subgroup, might be associated with a poor prognosis in primary OSCC. These findings indicated that VISTA might be a potential immunotherapeutic target in OSCC treatment.