Overexpression of CD155 is associated with PD-1 and PD-L1 expression on immune cells, rather than tumor cells in the breast cancer microenvironment

An integrative bioinformatics investigation and experimental validation of chromobox family in diffuse large B-cell lymphoma

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) is one of the most aggressive malignant tumors. Chromobox (CBX) family plays the role of oncogenes in various malignancies.

METHODS

The transcriptional and protein levels of CBX family were confirmed by GEPIA, Oncomine, CCLE, and HPA database. Screening of co-expressed genes and gene function enrichment analysis were performed by GeneMANIA and DAVID 6.8. The prognostic value, immune cell infiltration and drug sensitivity analysis of CBX family in DLBCL were performed by Genomicscape, TIMER2.0, and GSCALite database. Confirmatory Tests of CBX family protein expression in DLBCL were performed by immunohistochemistry.

RESULTS

The mRNA and protein expressions of CBX1/2/3/5/6 were higher in DLBCL tissues than control groups. Enrichment analysis showed that the functions of CBX family were mainly related to chromatin remodeling, methylation-dependent protein binding, and VEGF signaling pathway. The high mRNA expressions of CBX2/3/5/6 were identified to be associated with short overall survival (OS) in DLBCL patients. Multivariate COX regression indicated that CBX3 was independent prognostic marker. Immune infiltration analysis revealed that the mRNA expressions of CBX family (especially CBX1, CBX5, and CBX6) in DLBCL were significantly correlated with the infiltration of most immune cells (including B cells, CD8 + T cells, CD4 + T cells, neutrophils, monocytes, macrophages, and Treg cells). Meanwhile, there was a strong correlation between the expression levels of CBX1/5/6 and surface markers of immune cells, such as the widely studied PVR-like protein receptor/ligand and PDL-1 immune checkpoint. Notably, our study found that DLBCL cells with CBX1 over-expression were resistant to the common anti-tumor drugs, but CBX2/5 had two polarities. Finally, we confirmed the higher expressions of CBX1/2/3/5/6 in DLBCL tissues compared with control groups by immunohistochemistry.

CONCLUSION

We provided a detailed analysis of the relationship between the CBX family and the prognosis of DLBCL. Distinguished from other studies, We found that high mRNA expressions of CBX2/3/5/6 were associated with poor prognosis in DLBCL patients, and Multivariate COX regression indicated that CBX3 was independent prognostic marker. Besides, our study also found an association between the CBX family and anti-tumour drug resistance, and provided a relationship between CBX family expression and immune cell infiltration.

Immunohistochemical expression of CD155 in invasive female breast carcinoma and its correlation with tumor infiltrating natural killer cells

Background

CD155 is an immune checkpoint protein that interacts with ligands on natural killer cells to regulate the tumor associated immunity. CD155 overexpression has been detected in many human cancer types. CD155 and its pathways are promising tumor immunotherapy targets. We aimed to evaluate the immunohistochemical expression of CD155 in invasive breast carcinomas and to correlate such expression with the pathological parameters of the tumors and also with natural killer - tumor infiltrating lymphocytes (NK-TILs) density in breast carcinomas tissue as highlighted by CD56 immunostaining. This study included 78 cases of breast carcinomas. Immunohistochemistry was performed using antibodies against CD155 which was detected on the tumor cells and CD56 as a marker for stromal NK cells.

Results

CD155 expression by the tumor cells was detected in 30.8% of the cases and correlated significantly with advanced prognostic stage, Estrogen receptor (ER) and Progesterone receptor (PR) negativity, high Ki-67 index and Human epidermal receptor 2 (HER2) enriched molecular subtype. High stromal TILs CD56 expression was detected in 28.2% of the cases and correlated significantly with high histologic grade, PR negativity, HER2 neu over-expression, high Ki-67 index, high stromal TILs and more aggressive molecular subtypes; triple negative breast cancer, HER2 enriched and Luminal B-HER2 positive. Finally, statistically significant direct correlation was detected between Tumor cells CD155 expression and high TILs CD56 expression.

Conclusions

Our results support tumor cell CD155 expression and TILs CD56 expression in breast cancers that are high grade, TILs rich and hormone receptors negative, highlighting those cases as possible candidates for CD155 targeted therapy.

Correlation of the TIGIT-PVR immune checkpoint axis with clinicopathological features in triple-negative breast cancer

Background

T cell immunoreceptor with Ig and ITIM domains (TIGIT) interacts with poliovirus receptor (PVR) to contribute to cancer immune escape. Recently, TIGIT and PVR have been identified as promising immunotherapy targets. Their gene expression is upregulated in many solid tumors, but their protein expression level is not well documented, particularly in triple negative breast cancer (TNBC), the breast cancer subtype that most benefit from immunotherapy.

Methods

TIGIT and PVR expression levels were assessed by immunohistochemistry in 243 surgically resected localized TNBC and then their relationship with clinical-pathological features and clinical outcome was analyzed.

Results

TIGIT expression was observed in immune cells from the tumor microenvironment, whereas PVR was mainly expressed by tumor cells. High TIGIT expression was significantly associated with age (p=0.010), histological grade (p=0.014), non-lobular histology (p=0.024), adjuvant chemotherapy (p=0.006), and various immune cell populations (tumor infiltrating lymphocytes (TILs), CD3⁺, CD8⁺, PD-1⁺ cells; all p<0.0001), PD-L1⁺ tumor cells (p<0.0001), and PD-L1⁺ stromal cells (p=0.003). Infiltration by TIGIT⁺ cells tended to be higher in non-molecular apocrine tumors (p=0.088). PVR was significantly associated with histological grade (p<0.0001), the basal-like (p=0.003) and non-molecular apocrine phenotypes (p=0.039), high TILs infiltration (p=0.011), CD3⁺ (p=0.002), CD8⁺ (p=0.024) T cells, and PD-L1 expression in tumor (p=0.003) and stromal cells (p=0.001). In univariate analysis, only known prognostic factors (age, tumor size, lymph node status, adjuvant chemotherapy, TILs and CD3⁺ T-cell infiltrate) were significantly associated with relapse-free survival (RFS) and overall survival. High TIGIT and PVR expression levels tended to be associated with longer RFS (p=0.079 and 0.045, respectively). The analysis that included only non-molecular apocrine TNBC revealed longer RFS for tumors that strongly expressed TIGIT or PVR (p=0.025 for TIGIT and 0.032 for PVR).

Conclusions

These results indicated that in TNBC, TIGIT⁺ cells can easily interact with PVR to exert their inhibitory effects. Their wide expression in TNBC and their association with other immune checkpoint components suggest the therapeutic interest of the TIGIT-PVR axis.

Expression of Membranous CD155 Is Associated with Aggressive Phenotypes and a Poor Prognosis in Patients with Bladder Cancer

Objective: To investigate the relationship between clinicopathological findings and membranous CD155 (mCD155) or cytoplasmic CD155 (cCD155) expression in bladder cancer (BC). Methods: We retrospectively analyzed 103 patients with BC who underwent radical cystectomy between 1990 to 2015 at Kitasato University Hospital. Immunohistochemical staining was performed to evaluate CD155 expression in tumor cells. Cases with > 10% expression on the membrane or cytoplasm of tumor cells were positive. The Fisher′s exact test was used for categorical variables and the Kaplan−Meier method was used for survival outcomes. Univariate and multivariate Cox regression hazard models were used to evaluate the survival risk factors. Results: Cases that were mCD155-positive were associated with high-grade tumors (p = 0.02), nodal status (p < 0.01), and pT stage (p = 0.04). No association with any clinicopathological factor was observed in the cCD155 cases. Kaplan−Meier analysis showed that mCD155-positive cases had shorter periods of recurrence-free survival (p = 0.015) and cancer-specific survival (p = 0.005). Only nodal status was an independent predictor for both cancer-specific survival and recurrence-free survival in multivariate analysis (p = 0.02 and p < 0.01, respectively). Conclusion: mCD155 expression may be a marker of an aggressive phenotype and a poor prognosis in patients with BC.

Immune checkpoint CD155 promoter methylation profiling reveals cancer-associated behaviors within breast neoplasia

BACKGROUND

CD155 immune checkpoint has recently emerged as a compelling immunotherapeutic target. Epigenetic DNA methylation changes are recognized as key molecular mechanisms in cancer development. Hence, the identification of methylation markers that are sensitive and specific for breast cancer may improve early detection and predict prognosis. We speculate that CD155 promoter methylation can be a valuable epigenetic biomarker, based upon strong indications for its immunoregulatory functions.

METHODS

Methylation analyses were conducted on 14 CpGs sites in the CD155 promoter region by bisulfite pyrosequencing. To elucidate the related gene expression changes, a transcriptional study using RT-qPCR was performed. Statistical analyses were performed to evaluate correlations of CD155 methylation profiles with mRNA expression together with clinical-pathological features, prognosis and immune infiltrate.

RESULTS

CD155 promoter methylation profile was significantly associated with SBR grade, tumor size, molecular subgroups, HER2 and hormonal receptors expression status. Low CD155 methylation rates correlated with better prognosis in univariate cox proportional hazard analysis and appeared as an independent survival predictor in cox-regression multivariate analysis. Further, methylation changes at CD155 specific CpG sites were consistent with CD155 membranous mRNA isoform expression status. Statistical analyses also showed a significant association with immune Natural Killer cell infiltrate when looking at the CpG7, CpG8, CpG9 and CpG11 sites.

CONCLUSION

Altogether, our results contribute to a better understanding of the impact of CD155 immune checkpoint modality expression in breast tumors, revealing for the first time that specific CpG sites from CD155 promoter may be a potential biomarker in breast cancer monitoring.