PVRL2 Research Articles

The Nectin family ligands, PVRL2 and PVR, in cancer immunology and immunotherapy.

In recent years, immunotherapy has emerged as a crucial component of cancer treatment. However, its efficacy remains limited across various cancer types, highlighting unmet needs. Poliovirus receptor-related 2 (PVRL2) and Poliovirus receptor (PVR) are members of the Nectin and Nectin-like Molecules family, known for their role as cell-cell adhesion molecules. With the development of immunotherapy, their involvement in tumor immune mechanisms as immune checkpoint factors has garnered significant attention. PVRL2 and PVR are predominantly expressed on tumor cells and antigen-presenting cells, binding to PVRIG and TIGIT, respectively, which are primarily found on T and NK cells, thereby suppressing antitumor immunity. Notably, gynecological cancers such as ovarian and endometrial cancers exhibit high expression levels of PVRL2 and PVR, with similar trends observed in various other solid and hematologic tumors. Targeting these immune checkpoint pathways offers a promising therapeutic avenue, potentially in combination with existing treatments. However, the immunomodulatory mechanism involving these bindings, known as the DNAM-1 axis, is complex, underscoring the importance of understanding it for developing novel therapies. This article comprehensively reviews the immunomodulatory mechanisms centered on PVRL2 and PVR, elucidating their implications for various cancer types.

A minor allele of the haplotype located in the 19q13 loci is associated with a decreased risk of hyper-LDL-cholesterolemia, and a balanced diet and high protein intake can reduce the risk

BackgroundAlthough the human chromosome 19q13 loci are reported to be associated with hyper-LDL-cholesterolemia, the haplotype of single nucleotide polymorphism (SNP) has not been studied. Therefore, the association of the haplotype in 19q13 loci with hyper-LDL-cholesterolemia was determined and their interactions with lifestyles and nutrient intakes were evaluated in 28,445 Koreans aged > 40 years.MethodsSNPs were selected from 19q13 loci that had an association with hyper-LDL-cholesterolemia with the adjustment of confounders (age, gender, area of residence, and body mass index). Haplotype was constructed from the selected SNPs. An adjusted odds ratio of the haplotype for hyper-LDL-cholesterolemia and the interaction between haplotype and lifestyles was analyzed after adjusting for covariates.ResultsHyper-LDL-cholesterolemia had an association with apolipoprotein E (APOE)_ rs7259620, translocase of outer mitochondrial membrane 40(TOMM40)_rs157581, poliovirus receptor-related 2(PVRL2)_rs403155, exocyst complex component 3-like 2(EXOC3L2)_ rs10406604 and CD3e molecule-associated protein (CD3EAP)_rs3212986 in 19q13. The haplotype of these SNPs had a negative association with hyper-total-cholesterolemia and hyper-LDL-cholesterolemia by 0.669 and 0.684 times, respectively, after adjusting for covariates. The incidence of cardiovascular diseases, especially myocardial infarction, had a negative association with the minor alleles. The balanced diet pattern (BD) and protein intake had a significant interaction with the haplotype: the major-allele of the haplotype exhibited a positive association with hyper-LDL-cholesterolemia, compared to the minor allele, only when combined with a high intake of BD. The participants with the minor allele exhibited a lower hyper-LDL-cholesterolemia risk compared to those with the major allele only with high protein intake.ConclusionThe minor allele of haplotype located in 19q13 loci protected against hyper-LDL-cholesterolemia, especially with BD and high protein intake. The minor allele also had a negative association with myocardial infarction events.

The expression and clinical significance of immune checkpoints in acute myeloid leukemia

Objective To find potential effective immunotherapy targets for acute myeloid leukemia (AML) by analyzing the expression and clinical significance of different immune checkpoints. Methods Gene expression profiles of AML cell lines (GSE57083) and tissues (GSE37642) were downloaded from GEO database. Then different immune checkpoints expression and clinical significance were analyzed with R studio and GraphPad software. Results In 16 AML cell lines, the expression rank of 11 immune checkpoints genes was LGALS9, PVRL2, PVR, PDCD1, TIM3, CTLA4, PDL1, GITR, LAG3, PDL2, GITRL, and among which LGALS9, PVRL2, GITR had larger variation between different cells. In AML tissues, the expression rank of immune checkpoint was LGALS9, PVRL2, TIM3, PDCD1, CTLA4, LAG3, GITR, PDL1, PVR, GITRL, PDL2. Survival analysis revealed high expression of PVR and LGALS9 was associated with poor prognosis, while the survival time had no significant difference in other genes. Conclusions PVR is highly expressed in AML tumor cells, and LGALS9 is highly expressed in both AML tumor cells and tissues. High expression of PVR and LGALS9 is associated with poor prognosis of AML patients, which may be a potential effective immunotherapy target for AML. Key words: Leukemia, myeloid, acute; Immunotherapy; Genes, cell cycle checkpoints; Molecular targeted therapy; Computational biology

Genome-Wide Association and Mechanistic Studies Indicate That Immune Response Contributes to Alzheimer’s Disease Development

Alzheimer’s disease (AD) is the most common cause of dementia. Although genome-wide association study (GWAS) have reported hundreds of single-nucleotide polymorphisms (SNPs) and genes linked to AD, the mechanisms about how these SNPs modulate the development of AD remain largely unknown. In this study, we performed GWAS for three traits in cerebrospinal fluid (CSF) and one clinical trait in the Alzheimer’s Disease Neuroimaging Initiative (ADNI) cohort. Our analysis identified five most significant AD related SNPs (FDR < 0.05) within or proximal to APOE, APOC1, and TOMM40. One of the SNPs was co-inherited with APOE allele 4, which is the most important genetic risk factor for AD. Three of the five SNPs were located in promoter or enhancer regions, and transcription factor (TF) binding affinity calculations showed dramatic changes (| Log2FC| > 2) of three TFs (PLAG1, RREB1, and ZBTB33) for two motifs containing SNPs rs2075650 and rs157580. In addition, our GWAS showed that both rs2075650 and rs157580 were significantly associated with the poliovirus receptor-related 2 (PVRL2) gene (FDR < 0.25), which is involved in spreading of herpes simplex virus (HSV). The altered regulation of PVRL2 may increase the susceptibility AD patients to HSV and other virus infections of the brain. Our work suggests that AD is a type of immune disorder driven by viral or microbial infections of the brain during aging.

Immune checkpoints PVR and PVRL2 are prognostic markers in AML and their blockade represents a new therapeutic option

Immune checkpoints are promising targets in cancer therapy. Recently, poliovirus receptor (PVR) and poliovirus receptor-related 2 (PVRL2) have been identified as novel immune checkpoints. In this investigation we show that acute myeloid leukemia (AML) cell lines and AML patient samples highly express the T-cell immunoreceptor with Ig and ITIM domains (TIGIT) ligands PVR and PVRL2. Using two independent patient cohorts, we could demonstrate that high PVR and PVRL2 expression correlates with poor outcome in AML. We show for the first time that antibody blockade of PVR or PVRL2 on AML cell lines or primary AML cells or TIGIT blockade on immune cells increases the anti-leukemic effects mediated by PBMCs or purified CD3+ cells in vitro. The cytolytic activity of the BiTE® antibody construct AMG 330 against leukemic cells could be further enhanced by blockade of the TIGIT-PVR/PVRL2 axis. This increased immune reactivity is paralleled by augmented secretion of Granzyme B by immune cells. Employing CRISPR/Cas9-mediated knockout of PVR and PVRL2 in MV4-11 cells, the cytotoxic effects of antibody blockade could be recapitulated in vitro. In NSG mice reconstituted with human T cells and transplanted with either MV4-11 PVR/PVRL2 knockout or wildtype cells, prolonged survival was observed for the knockout cells. This survival benefit could be further extended by treating the mice with AMG 330. Therefore, targeting the TIGIT-PVR/PVRL2 axis with blocking antibodies might represent a promising future therapeutic option in AML.

Abstract 2003: Antibody against TIGIT (T cell immunoreceptor with Ig and ITIM domains) induces anti-tumor immune response and generates long-term immune memory

Abstract T cell immunoreceptor with Ig and ITIM domains (TIGIT) is a co-inhibitory molecule containing an immunoreceptor tyrosine-based inhibition motif (ITIM) within its cytoplasmic tail, and is highly expressed on regulatory T cells and activated CD4+ T, CD8+ T, and NK cells. TIGIT competes with CD226, which contains an immunoreceptor tyrosine-based activation motif (ITAM) within its cytoplasmic tail for ligands poliovirus receptor (PVR) and poliovirus receptor-related 2 (PVRL2), with higher affinity to PVR. The ligands are expressed on the surface of antigen presenting cells and at high levels on most tumors. Therefore, when TIGIT is present, the ligands preferentially engage TIGIT rather than CD226, leading to cell suppression. We have generated antibodies against TIGIT that blocks ligand binding and inhibits TIGIT signaling. The clinical candidate, OMP-313M32 binds human TIGIT but not rodent and non-human primate TIGIT. Therefore, a surrogate antibody was generated for pre-clinical assessments in mice. Antibody 313R12 is an anti-mouse TIGIT antibody that can block mouse PVR ligand binding and inhibit TIGIT signaling in a manner similar to the clinical candidate OMP-313M32. 313R12 inhibited the growth of syngeneic colon and kidney tumors in immune competent mice. In some cases, anti-TIGIT antibody 313R12 caused complete tumor regression and a potent anti-tumor immune memory response as demonstrated by the lack of tumor growth upon re-challenge of mice that remained tumor-free after prior anti-TIGIT treatment. Mechanistically, anti-TIGIT antibody 313R12 was shown to induce a Th1 response and increase cytotoxic T lymphocyte (CTL) activity. By in vivo depletion of T cell populations, we have shown that CD8 T cell depletion completely abrogated the anti-TIGIT therapeutic effect, whereas CD4 T cell depletion led to partial reversal of efficacy of anti-TIGIT. Therefore, both CD4+ and CD8+ T cells are critical for anti-TIGIT-mediated immune responses. Using mice reconstituted with human hematopoietic stem cells, we also demonstrated that the clinical candidate OMP-313M32 inhibits patient-derived melanoma tumor growth. Taken together, these data demonstrate that anti-TIGIT therapy suppresses tumor growth and generates long-term immunological memory against multiple tumors. Citation Format: Angie Inkyung Park, Minu Srivastava, Erin Mayes, Hyun-Bae Jie, Rui Yun, Christopher Murriel, Ming-hong Xie, Andrew Lam, May Ji, Fumiko Axelrod, Jorge Monteon, John Lewicki, Tim Hoey, Austin Gurney. Antibody against TIGIT (T cell immunoreceptor with Ig and ITIM domains) induces anti-tumor immune response and generates long-term immune memory [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2003. doi:10.1158/1538-7445.AM2017-2003

Expression of Novel Immune Checkpoint Molecules PVR and PVRL2 Confers a Negative Prognosis to Patients with Acute Myeloid Leukemia and Their Blockade Augments T-Cell Mediated Lysis of AML Cells Alone or in Combination with the BiTE® Antibody Construct AMG 330

Background:T-cell activity is regulated by immune checkpoints to maintain the sensitive balance of co-stimulatory and inhibitory immune signals. Therapeutic blockade of checkpoint molecules on tumor or T cells such as CTLA-4 or PD-L1 has shown clinical success in several tumor types including Hodgkin´s disease. Furthermore, Blinatumomab, a bispecific T-cell engager (BiTE antibody construct) directing cytotoxic T cells to CD19 positive leukemic cells has been approved for treatment of acute lymphoblastic leukemia. The CD33 specific BiTE antibody construct AMG 330 has been developed for the therapy of acute myeloid leukemia (AML) and will be evaluated in phase I studies shortly. In our current study, we investigated the therapeutic utility of blockade of the novel checkpoint proteins PVR (poliovirus receptor) and PVRL2 (poliovirus receptor-related 2) alone and in combination with AMG 330 in AML.Methods and results:Samples from 140 treatment naive patients with newly diagnosed AML (AMLSG 07-04, NCT00151242) were analyzed by RT-qPCR for expression of the immune checkpoint molecules PVR, PVRL2 and Galectin-9 (Gal-9). Expression was correlated with patient demographics (age, karyotype, FLT3 mutation status) and clinical survival data by multivariate cox regression. The majority of patients showed mRNA expression of PVR (94%), PVRL2 (95%) and Gal-9 (92%). In a multivariate stepwise cox regression for overall survival, an unfavorable karyotype, high PVR and high Gal-9 expression were identified as independent prognostic markers (p<0.001, HR: 2.10, CI 1.39-3.15 for the karyotype; p=0.001, HR: 1.64, CI 1.21-2.21 for PVR and p<0.001, HR: 0.67, CI 0.54-0.84 for Gal-9). Due to a high correlation between PVR and PVRL2 (Pearson's rho=0.827, p<0.001), PVRL2 was removed during the stepwise process. Nevertheless, if PVR was excluded from the multivariate cox regression, PVRL2 remained as significant term in the stepwise procedure in addition to the karyotype and Gal-9 (p=0.003, HR: 1.58, CI 1.17-2.13 for PVRL2).In a second, independent patient cohort containing microarray-based gene expression and clinical data of 291 AML patients (Verhaak et.al., Haematologica 2009;94) a high PVR and PVRL2 expression in contrast to expression of CD80, CD86 or PD-L1 was associated with poor overall survival (log-rank test p=0.003 and p=0.032, respectively).In in vitro killing assays the therapeutic effect of PVR and PVRL2 blockade was studied by FACS using 7-AAD staining. AML cell lines MV4-11, Kasumi-1 and Molm-13 were preincubated with blocking antibodies against PVR, PVRL2 or both and co-cultured for 24h with peripheral blood mononuclear cells (PBMCs) of healthy donors in the presence or absence of AMG 330.In the absence of AMG 330, the cell kill of MV4-11 increased from 12.6±4.7% (control) to 33.0±8.8% (PVR), to 40.4±10.4% (PVRL2) and to 56.0±12.0% (both PVR + PVRL2). In the presence of suboptimal concentration of AMG 330 (0.1 ng/ml) MV4-11 cell lysis was 29.4±9.0% (AMG 330 alone), 49.7±12.6% (AMG 330 + PVR), 57.9±11.3% (AMG 330 + PVRL2) and 70.0±9.8% (AMG 330 + PVR + PVRL2; n=4, p<0.05 for all comparisons). Comparable results were found for Kasumi-1 and Molm-13 with blockade of both checkpoint inhibitors being the most effective treatment, although additive effects of antibodies against PVR and PVRL2 could not be verified in all cases (data not shown). To confirm specificity of the approach and to exclude effects caused by antibody dependent cellular cytotoxicity (ADCC), PVR and PVRL2 double knockouts of the cell line MV4-11 were generated by CRISPR/Cas-9. Significantly increased killing was observed in PVR and PVRL2 double knockout cells compared to wild-type cells (40.5±8.1 % vs. 25.9±9.1; n=3, p<0.001). Further experiments using an irrelevant antibody against CD117 or Fcγ receptor blockade by purified IgG antibodies excluded ADCC confirming the functional relevance of PVR/PVRL2 blockade.Conclusion:The expression of immune checkpoint ligands PVR and PVRL2 confers a negative prognosis to AML patients possibly due to immune evasion. We could further show that the killing of AML cells by PBMCs could be augmented by blockade of these novel checkpoint inhibitors. Furthermore, addition of PVR and/or PVRL2 blocking antibodies to AMG 330 could enhance cytotoxicity. Therefore, blockade of PVR and PVRL2 represents a promising target for the treatment of AML. DisclosuresKischel:Amgen Research (Munich) GmbH: Employment. Stienen:Amgen Research (Munich) GmbH: Employment. Friedrich:Amgen Research (Munich) GmbH: Employment. Lutteropp:Amgen Research (Munich) GmbH: Employment. Nagorsen:Amgen: Employment, Equity Ownership, Patents & Royalties: Inventor on blinatumomab-related patent.

AB166. Replicative genetic association analysis reveals genetic markers of schizophrenia and Alzheimer’s disease in Russians and Kazakhs and demonstrates overlapping associations pattern between two diseases

Replicative analysis of genetic markers, previously identified in genome-wide association studies (GWAS) for neuropsychiatric diseases, in population of various origins may contribute to better understanding of genetic composition of the diseases. In this study 50 SNPs found in GWAS for schizophrenia (SZ), Alzheimer’s diseases (AD) and cognitive endophenotypes were genotyped in patients and control samples from Russian and Kazakh populations. Eight polymorphic markers (SNPs in regions of genes for APOЕ, APOJ, CSMD1, CCDC60, SNX29, PICALM, NOTCH4 and NRIP1) were associated with AD in Russian population. Associations of 10 genetic markers with SZ in Russian populations (markers in regions of genes for NRGN, KCNB2, NRIP1, CCDC60, LSM1, LOC100129100/LOC100509857, CSMD1, CPVL, POM121L2 and NDE1P1/PRMT6) and 8 genetic markers in Kazakh population (VRK2, KCNB2, CPVL, BRD1, PVRL2, ARHGAP1, CD33 u GPR89P/TRV-AAC1-5) were replicated. Multidimensional reduction methods revealed epistatic interaction of several genetic loci in formation of susceptibility to SZ in populations of various ethnic origins. Overlapping fields of genetic associations for AD and SZ, demonstrating some similarity in inherited background for both diseases, were found. This interaction may be implemented through common unknown levels in pathogenesis of AD and SZ, mediated by cognitive endophenotypes. Bioinformatic analysis of biological functions of associated genes revealed that among primary biological processes enriched by genes under study are the processes of lipid metabolism, cellular interactions, various regulatory and transport processes in neural cells, processes of immune response regulation. Substantial part of investigated genes forms an interacting network, which consisted of distinct clusters corresponding to major biological processes, were genes under study are involved, and to basic molecular functions of their products. In general, data obtained in the project, extend the understanding of genetic component in neuro-psychiatric diseases, as well as the biological processes and functions, implemented in the manifestation of genetic susceptibility to AD and SZ.

Association Analysis of the Poliovirus Receptor Related-2 Gene in Patients with Nonsyndromic Cleft Lip with or Without Cleft Palate

Nonsyndromic cleft lip with or without cleft palate (nsCL/P) has a complex etiology, which involves both genetic and environmental factors. In this study, we carried out mutation screening of the poliovirus receptor related-2 (PRR2) gene, located at an orofacial cleft (OFC) linkage region 19q13 (OFC3). PRR2 Sau96I (A/G) genotypes of 212 patients with nsCLP and 221 controls were detected using a polymerase chain reaction-restriction fragment length polymerase assay. The results showed significant differences in the genotype and allele distribution of the PRR2 Sau96I (A/G) between the cases and controls. The GG genotype resulted in a significantly raised odds ratio (OR) compared with the AA genotype (OR=3.031; 95% confidence interval: 1.601, 5.742). The G allele showed a significant elevated risk (χ(2) = 26.991, p=0.000, OR=2.147; 95% confidence interval: 1.605, 2.871) compared with the A allele. Hence, our results support the hypothesis that this polymorphism contributes to the risk of nsCL/P, suggesting a possible etiologic role of PRR2 in nsCL/P.

The poliovirus receptor related 2 (PRR2) and apolipoprotein E genes and coronary heart disease.

Recently, we localized the Human Poliovirus Receptor Related 2 Gene (PRR2) 17kb centromeric to the gene for apolipoprotein E (APOE). Common polymorphisms in the latter have been found, in some studies, to be related to coronary heart disease (CHD) but the PRR2 gene has not been studied in this context. Here, we examined relationships between a PRR2 Sau96I (A/G) polymorphism, the epsilon2, 3 and 4 alleles of APOE and CHD. Consecutive Caucasian patients (n = 640) < 50 years with angiographically documented coronary obstructive disease and/or with unequivocal myocardial infarction were compared with 624 control subjects, aged 30-50 years, randomly selected from the community and without a history of CHD. An excess of PRR2-A homozygotes was observed in cases (20% vs. 15%; OR 1.4, CI 1.04-1.86, P = 0.026) particularly in those with single vessel disease (OR 1.7, CI 1.2-2.4, P <0.01). The A allele was in linkage disequilibrium with the epsilon4 allele and the G allele with the epsilon2. Overrepresentation of the A allele and underrepresentation of the G allele in the CHD group did not reach significance (P = 0.054). While the epsilon2 allele was underrepresented in the CHD group (OR 0.64, CI 0.46-0.89, P = 0.009), the epsilon4 allele was not significantly overrepresented. The relationship between the PRR2 Sau96I (A/G) polymorphism and early onset coronary artery disease may be due to linkage disequilibrium with the APOE gene and underrepresentation, or a protective effect, of the epsilon2 allele. Alternatively, since A allele homozygosity is particularly overrepresented, the relationship could be more direct, perhaps through a viral association.

The Human Poliovirus Receptor Related 2 Protein Is a New Hematopoietic/Endothelial Homophilic Adhesion Molecule

AbstractWe have recently described Poliovirus Receptor Related 2 (PRR2), a new cell surface molecule homologous to the poliovirus receptor (PVR/CD155). Both molecules are transmembrane glycoproteins belonging to the Ig superfamily (IgSF). They contain 3 Ig domains of V, C2, and C2 types in their extracellular regions that share 51% aa identity. The PRR2 gene encodes two mRNA isoforms of 3.0 kb (hPRR2α [short form]) and 4.4 kb (hPRR2δ [long form]), both widely expressed in human tissues, including hematopoietic cells. To further characterize PRR2 expression during hematopoiesis and to analyze its function, we have developed a monoclonal antibody (MoAb) directed against its extracellular region (R2.477). PRR2 was expressed in 96% of the CD34+, 88% of the CD33+, and 95% of the CD14+ hematopoietic lineages and faintly in the CD41 compartment. Ectopic expression of both PRR2 cDNAs induced marked cell aggregation. A soluble chimeric receptor construct with the Fc fragment of human IgG1 (PRR2-Fc) as well as a fab fragment of the anti-PRR2 MoAb (R2.477) inhibit aggregation. PRR2-Fc binds specifically to PRR2-expressing cells. These results suggest that PRR2 is a homophilic adhesion receptor. PRR2 was also expressed at the surface of endothelial cells at the intercellular junctions of adjacent cells but not at the free cellular edges. Homophilic interactions are associated with dimerization of isoforms of PRR2 and lead to the tyrosine phosphorylation of PRR2δ. Altogether, these results suggest that homophilic properties of PRR2 could participate to the regulation of hematopoietic/endothelial cell functions.

The Human Poliovirus Receptor Related 2 Protein Is a New Hematopoietic/Endothelial Homophilic Adhesion Molecule

We have recently described Poliovirus Receptor Related 2 (PRR2), a new cell surface molecule homologous to the poliovirus receptor (PVR/CD155). Both molecules are transmembrane glycoproteins belonging to the Ig superfamily (IgSF). They contain 3 Ig domains of V, C2, and C2 types in their extracellular regions that share 51% aa identity. The PRR2 gene encodes two mRNA isoforms of 3.0 kb (hPRR2 [short form]) and 4.4 kb (hPRR2δ [long form]), both widely expressed in human tissues, including hematopoietic cells. To further characterize PRR2 expression during hematopoiesis and to analyze its function, we have developed a monoclonal antibody (MoAb) directed against its extracellular region (R2.477). PRR2 was expressed in 96% of the CD34+, 88% of the CD33+, and 95% of the CD14+ hematopoietic lineages and faintly in the CD41 compartment. Ectopic expression of both PRR2 cDNAs induced marked cell aggregation. A soluble chimeric receptor construct with the Fc fragment of human IgG1 (PRR2-Fc) as well as a fab fragment of the anti-PRR2 MoAb (R2.477) inhibit aggregation. PRR2-Fc binds specifically to PRR2-expressing cells. These results suggest that PRR2 is a homophilic adhesion receptor. PRR2 was also expressed at the surface of endothelial cells at the intercellular junctions of adjacent cells but not at the free cellular edges. Homophilic interactions are associated with dimerization of isoforms of PRR2 and lead to the tyrosine phosphorylation of PRR2δ. Altogether, these results suggest that homophilic properties of PRR2 could participate to the regulation of hematopoietic/endothelial cell functions.