Immunoglobulin genes implicated in glioma risk

miR-363-3p induces EMT via the Wnt/β-catenin pathway in glioma cells by targeting CELF2

In our previous study, we reported that CELF2 has a tumour‐suppressive function in glioma. Here, we performed additional experiments to elucidate better its role in cancer. The expression profile of CELF2 was analysed by the GEPIA database, and Kaplan–Meier curves were used to evaluate the overall survival rates. Four different online databases were used to predict miRNAs targeting CELF2, and the luciferase assay was performed to identify the binding site. The biological effects of miR‐363‐3p and CELF2 were also investigated in vitro using MTT, Transwell, and flow cytometry assays. Western blotting, qPCR, and TOP/FOP flash dual‐luciferase assays were performed to investigate the impact of miR‐363‐3p and CELF2 on epithelial‐to‐mesenchymal transition (EMT) and the Wnt/β‐catenin pathway. The effect of miR‐363‐3p was also tested in vivo using a xenograft mouse model. We observed an abnormal expression pattern of CELF2 in glioma cells, and higher CELF2 expression correlated with better prognosis. We identified miR‐363‐3p as an upstream regulator of CELF2 and confirmed its direct binding to the 3′‐untranslated region of CELF2. Cell function experiments showed that miR‐363‐3p affected multiple aspects of glioma cells. Suppressing miR‐363‐3p expression inhibited glioma cell proliferation and invasion, as well as promoted cell death via attenuating EMT and blocking the Wnt/β‐catenin pathway. These effects could be abolished by the downregulation of CELF2. Treatment with ASO‐miR‐363‐3p decreased tumour size and weight in nude mice. In conclusion, miR‐363‐3p induced the EMT, which resulted in increased migration and invasion and reduced apoptosis in glioma cell lines, via the Wnt/β‐catenin pathway by targeting CELF2.

LncRNA ANCR promotes glioma cells invasion, migration, proliferation and inhibits apoptosis via interacting with EZH2 and repressing PTEN expression

Recently, the role of long noncoding RNA (lncRNA) has been identified in human diseases, and we aim to explore the role of lncRNA antidifferentiation noncoding RNA (ANCR) in glioma. Expression of lncRNA ANCR, enhancer of zeste homolog 2 (EZH2), and phosphatase and tensin homolog (PTEN) in glioma tissues and cells was determined by RT-PCR or western blot assay. The correlation between expression of ANCR, EZH2, and PTEN in glioma tissues was analyzed using Pearson test. The apoptosis, transwell invasion, migration, colony formation, and proliferation assays were conducted to evaluate the influences of lncRNA ANCR depletion, EZH2 reduction, or PTEN elevation on the cell biology of glioma cells. The relationships between ANCR and EZH2, and between EZH2 and PTEN were confirmed through RIP, RNA pull-down, and chromatin immunoprecipitation assays. Our results indicated that ANCR and EZH2 were upregulated and PTEN was downregulated in glioma tissues and cell lines. ANCR expression was positively related to EZH2 expression, while PTEN expression was negatively related to ANCR/EZH2 expression. Inhibited ANCR, reduced EZH2, or elevated PTEN could reduce the ability of invasion, migration, and proliferation, and promote apoptosis of glioma cells. PTEN overexpression or EZH2 inhibition reversed the promotive role of ANCR upregulation in glioma cell growth and metastasis. Mechanistically, PTEN was upregulated in ANCR knockdown glioma cells. EZH2 interacted with ANCR in glioma cells. In conclusion, we have found that restrained ANCR could repress invasion, migration, and proliferation, as well as promote apoptosis of glioma cells through interacting with EZH2 and regulating the expression of PTEN, offering an effective therapeutic target for patients with glioma.

Replication of GWAS identifies RTEL1, CDKN2A/B, and PHLDB1 SNPs as risk factors in Portuguese gliomas patients

Diffuse gliomas are the most common malignant primary brain tumors and remain incurable. A better knowledge of the tumor etiology is required. Specific single nucleotides polymorphisms (SNPs) rs4977756 (CDKN2A/B), rs6010620 (RTEL1), rs498872 (PHLDB1), rs2736100 (TERT), and rs4295627 (CCDC26) have been associated with glioma susceptibility and are potential risk biomarkers. This study aimed to analyze five SNPs associated with glioma susceptibility, in the Portuguese population. SNPs were genotyped using the Sequenom MassARRAY platform in 127 gliomas and 180 controls. Unconditional logistic regression models were used to calculate odds ratio (OR) and 95% confidence intervals. The false-positive report probability was also assessed. The associations between polymorphisms and survival were evaluated using the log-rank test. It was found that the AG and GG genotypes of the rs4977756 (CDKN2A/B) were associated with an increased risk of gliomas (OR 1.85 and OR 2.38) and glioblastomas (OR 2.77 and OR 3.94). The GA genotype of the rs6010620 (RTEL1) was associated with a decreased risk of glioblastomas (OR 0.45). We also observed that the GA genotype of the rs498872 (PHLDB1) was associated with an increased risk of gliomas (OR 2.92) and glioblastomas (OR 2.39). No significant risk associations were found for the rs2736100 (TERT) and rs4295627 (CCDC26). In addition, the genotype AA of the rs498872 (PHLDB1) was associated with poor overall survival of gliomas patients (AA vs. GA, p = 0.037). The rs6010620 (RTEL1), rs4977756 (CDKN2A/B), and rs498872 (PHLDB1) are associated with glioma risk in the Portuguese population and these data may contribute to understanding gliomas etiology.

Host Genetics of Cytomegalovirus Pathogenesis

Human cytomegalovirus (HCMV) is a ubiquitous herpes virus (human herpes virus 5) with the highest morbidity and mortality rates compared to other herpes viruses. Risk groups include very young, elderly, transplant recipient, and immunocompromised individuals. HCMV may cause retinitis, encephalitis, hepatitis, esophagitis, colitis, pneumonia, neonatal infection sequelae, inflammatory, and age-related diseases. With an arsenal of genes in its large genome dedicated to host immune evasion, HCMV can block intrinsic cellular defenses and interfere with cellular immune responses. HCMV also encodes chemokines, chemokine receptors, and cytokines. Therefore, genes involved in human viral defense mechanisms and those encoding proteins targeted by the CMV proteins are candidates for host control of CMV infection and reactivation. Although still few in number, host genetic studies are producing valuable insights into biological processes involved in HCMV pathogenesis and HCMV-related diseases. For example, genetic variants in the immunoglobulin GM light chain can influence the antibody responsiveness to CMV glycoprotein B and modify risk of HCMV-related diseases. Moreover, CMV infection following organ transplantation has been associated with variants in genes encoding toll-like receptors (TLRs), programmed death-1 (PD-1), and interleukin-12p40 (IL-12B). A KIR haplotype (2DS4+) is proposed to be protective for CMV activation among hematopoietic stem cell transplant patients. Polymorphisms in the interferon lambda 3/4 (IFNL3/4) region are shown to influence susceptibility to CMV replication among solid organ transplant patients. Interestingly, the IFNL3/4 region is also associated with AIDS-related CMV retinitis susceptibility in HIV-infected patients. Likewise, interleukin-10 receptor 1 (IL-10R1) variants are shown to influence CMV retinitis development in patients with AIDS. Results from genome-wide association studies suggest a possible role for microtubule network and retinol metabolism in anti-CMV antibody response. Nevertheless, further genetic epidemiological studies with large cohorts, functional studies on the numerous HCMV genes, and immune response to chronic and latent states of infection that contribute to HCMV persistence are clearly necessary to elucidate the genetic mechanisms of CMV infection, reactivation, and pathogenesis.

MCL1 gene silencing promotes senescence and apoptosis of glioma cells via inhibition of the PI3K/Akt signaling pathway

Glioma is known to be the most prevalent primary brain tumor. In recent years, there has been evidence indicating myeloid cell leukemia-1 (MCL1) plays a role in brain glioblastoma. Therefore, the present study was conducted with aims of exploring the ability of MCL1 silencing to influence glioma cell senescence and apoptosis through the mediation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway. Glioma and tumor-adjacent tissues were collected in order to detect the presence of higher levels of MCL1 protein expression. Next, the mRNA and protein expression of MCL1, PI3K, Akt, B cell lymphoma 2 (Bcl2), Bcl2-associated X (Bax), B lymphoma Mo-MLV insertion region 1 homolog (Bmi-1), and phosphatase and tensin homolog (PTEN) were determined. Cell counting kit-8 assay was applied to detect cell proliferation, β-galactosidase staining for cell senescence, and flow cytometry for cell cycle entry and apoptosis. Initially, the results revealed higher positive expression rate of MCL1 protein, increased mRNA and protein expression of MCL1, PI3K, Akt, Bmi-1, and Bcl-2 and decreased that of Bax and PTEN in human glioma tissues. The silencing of MCL1 resulted in a decrease in mRNA and protein expression of PI3K, Akt, Bmi-1, and Bcl-2 and an increase in Bax and PTEN expressions in glioma cells. Moreover, silencing of MCL1 also inhibited cell proliferation and cell cycle entry in glioma cells, and promoted glioma cell senescence and apoptosis. In conclusion, the aforementioned results collectively suggested that the silencing of MCL1 promotes senescence and apoptosis in glioma cells through inhibiting the PI3K/Akt signaling pathway. Thus, decreasing the expression of MCL1 might have therapeutic functions in glioma. © 2018 IUBMB Life, 71(1):81-92, 2019.

Genetic variants of vascular endothelial growth factor predict risk and survival of gliomas

The vascular endothelial growth factor regulates angiogenesis that is increased in glioma. VEGF polymorphisms are thought to modulate vascular endothelial growth factor plasma levels and therefore may be implicated in glioma risk. We aimed to clarify the role of VEGF and von Willebrand factor polymorphisms in glioma susceptibility and prognosis. A case-control study of 126 glioma patients and 180 cancer-free controls was performed. Using Sequenom MassARRAY platform, 11 VEGF and 1 VWF polymorphisms were genotyped. Unconditional multivariate logistic regression models were used to calculate odds ratios and 95% confidence intervals. The associations between polymorphisms and survival were evaluated using a Cox regression model. Bonferroni's adjustment was used to correct for multiple testing. The VEGF polymorphism rs833061 was strongly associated with increased risk for glioma (odds ratio = 164.85) and glioblastoma (odds ratio = 155.66), confirmed after Bonferroni correction. Also, the VEGF polymorphisms rs3024994, rs2010963, and particularly the homozygous carriers of rs1005230 were associated with a worse prognosis for glioma and glioblastoma. Our data support a role of VEGF and VWF polymorphisms as glioma biomarkers, with additional potential relevance for molecular stratification of patients for anti-angiogenic therapies.

Association between γ marker, human leucocyte antigens and killer immunoglobulin-like receptors and the natural course of human cytomegalovirus infection: a pilot study performed in a Sicilian population

Natural killer (NK) cells provide a major defence against human cytomegalovirus (HCMV) infection through the interaction of their surface receptors, including the activating and inhibitory killer immunoglobulin-like receptors (KIRs), and human leucocyte antigen (HLA) class I molecules. Also γ marker (GM) allotypes, able to influence the NK antibody-dependent cell-mediated cytotoxicity, appear to be involved in the immunological control of virus infections, including HCMV. In some cases, their contribution requires epistatic interaction with other genes of the immune system, such as HLA. In the present report, with the aim of gaining insight into the immune mechanisms controlling HCMV, we have studied the possible associations among humoral and NK responses, and HCMV infections. In a previous study we assessed whether the KIR and HLA repertoire might influence the risk of developing symptomatic (n = 60) or asymptomatic (n = 60) disease after primary HCMV infection in the immunocompetent host. In the present study, the immunocompetent patients with primary symptomatic HCMV infection were genotyped for GM3/17 and GM23 allotypes, along with the 60 participants with a previous asymptomatic infection as controls. Notwithstanding the presence of missing data record, advanced missing data recovery techniques were able to show that individuals carrying the GM23 allotypes, both homozygous and heterozygous, GM17/17, HLA-C2 and Bw4^T KIR-ligand groups are associated with the risk of developing symptomatic infection. Our findings on the role of both cellular and humoral immunity in the control of HCMV infection should be of value in guiding efforts to reduce HCMV-associated health complications in the elderly, including immunosenescence, and in transplantation.

Human cytomegalovirus encoded chemokine receptor US28 activates the HIF-1α/PKM2 axis in glioblastoma cells

The human cytomegalovirus (HCMV) encoded chemokine receptor US28 promotes tumorigenesis through activation of various proliferative and angiogenic signaling pathways. Upon infection, US28 displays constitutive activity and signals in a G protein-dependent manner, hijacking the host's cellular machinery. In tumor cells, the hypoxia inducible factor-1α/pyruvate kinase M2 (HIF-1α/PKM2) axis plays an important role by supporting proliferation, angiogenesis and reprogramming of energy metabolism. In this study we show that US28 signaling results in activation of the HIF-1α/PKM2 feedforward loop in fibroblasts and glioblastoma cells. The constitutive activity of US28 increases HIF-1 protein stability through a Gαq-, CaMKII- and Akt/mTOR-dependent mechanism. Furthermore, we found that VEGF and lactate secretion are increased and HIF-1 target genes, glucose transporter type 1 (GLUT1) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), involved in glucose metabolism, are upregulated in US28 expressing cells. In addition, PKM2 is phosphorylated and found to be in a tumor-associated dimeric state upon US28 expression. Also in HCMV-infected cells HIF-1 activity is enhanced, which in part is US28-dependent. Finally, increased proliferation of cells expressing US28 is abolished upon inhibition of the HIF-1α/PKM2 cascade. These data highlight the importance of HIF-1α and PKM2 in US28-induced proliferation, angiogenesis and metabolic reprogramming.

Safety, pharmacokinetics and neutralization of the broadly neutralizing HIV-1 human monoclonal antibody VRC01 in healthy adults

VRC-HIVMAB060-00-AB (VRC01) is a broadly neutralizing HIV-1 monoclonal antibody (mAb) isolated from the B cells of an HIV-infected patient. It is directed against the HIV-1 CD4 binding site and is capable of potently neutralizing the majority of diverse HIV-1 strains. This Phase I dose-escalation study in healthy adults was conducted at the National Institutes of Health (NIH) Clinical Center (Bethesda, MD, USA). Primary objectives were the safety, tolerability and pharmacokinetics (PK) of VRC01 intravenous (i.v.) infusion at 5, 20 or 40 mg/kg, given either once (20 mg/kg) or twice 28 days apart (all doses), and of subcutaneous (s.c.) delivery at 5 mg/kg compared to s.c. placebo given twice, 28 days apart. Cumulatively, 28 subjects received 43 VRC01 and nine received placebo administrations. There were no serious adverse events or dose-limiting toxicities. Mean 28-day serum trough concentrations after the first infusion were 35 and 57 μg/ml for groups infused with 20 mg/kg (n = 8) and 40 mg/kg (n = 5) doses, respectively. Mean 28-day trough concentrations after the second infusion were 56 and 89 μg/ml for the same two doses. Over the 5-40 mg/kg i.v. dose range (n = 18), the clearance was 0.016 l/h and terminal half-life was 15 days. After infusion VRC01 retained expected neutralizing activity in serum, and anti-VRC01 antibody responses were not detected. The human monoclonal antibody (mAb) VRC01 was well tolerated when delivered i.v. or s.c. The mAb demonstrated expected half-life and pharmacokinetics for a human immunoglobulin G. The safety and PK results support and inform VRC01 dosing schedules for planning HIV-1 prevention efficacy studies.

Association between regulator of telomere elongation helicase 1 polymorphism and susceptibility to glioma

BACKGROUND

Glioma is the most devastating type of malignant brain tumors in adults. Genetic factors play important roles in the pathogenesis of glioma. In recent years, some studies found that there were significant association between regulator of telomere elongation helicase 1 rs6010620 polymorphism and glioma susceptibility, however, the results were controversial. The aim of this study was to obtain a more exact estimation of the association between regulator of telomere elongation helicase 1 rs6010620 polymorphism and glioma through a meta-analysis.

METHODS

The meta-analysis included 19 published case-control studies involving 8541 cases and 14226 controls. The included papers were searched from PubMed and Embase database. Odds ratio (OR) with 95% confidence interval (95% CI) were used to evaluate the association of regulator of telomere elongation helicase 1 rs6010620 polymorphism with glioma.

RESULTS

A significant association between regulator of telomere elongation helicase 1 rs6010620 polymorphism and glioma susceptibility was observed for GG vs. AA+AG (OR=1.28, 95% CI=1.14-1.43) and G vs. A (OR=1.07, 95% CI=1.03-1.10). Further subgroup analysis based on ethnicity showed similar results in Asians and Caucasians. In the subgroup analysis of source of control, a significant association between the G allele and glioma susceptibility were found in population-based group and hospital-based group.

CONCLUSIONS

The meta-analysis suggested that regulator of telomere elongation helicase 1 rs6010620 polymorphism was a risk factor for glioma. And this study also suggested that rs6010620 GG genotype and G allele may be indicators for the risk of glioma.

Immunoglobulin GM Genes, Cytomegalovirus Immunoevasion, and the Risk of Glioma, Neuroblastoma, and Breast Cancer

Human cytomegalovirus (HCMV), a common herpes virus, has been reported to be a risk factor for many diseases, including malignant diseases such as glioma, neuroblastoma, and breast cancer. Some of the HCMV-associated diseases (e.g., glioma) are rare. The question arises: how could a common virus be associated with uncommon diseases? Interactions between a major gene complex of the human immune system and a viral immunoevasion strategy – a probable mechanism of their co-evolutionary adaptation – may shed light on this paradox. To ensure its survival, HCMV has evolved sophisticated immunoevasion strategies. One strategy involves encoding decoy Fcγ receptors (FcγR), which may enable the virus to evade host immunosurveillance by avoiding the Fcγ-mediated effector consequences of anti-HCMV IgG antibody binding. Immunoglobulin G1 proteins expressing GM (γ marker) alleles 3 and 17 have differential affinity to the HCMV TRL11/IRL11-encoded FcγR, and thus act as effect modifiers of HCMV-associated malignancies. The high affinity GM 3 allele has been shown to be a risk factor for neuroblastoma, glioma, and breast cancer. Additional studies involving other viral FcγRs as well as GM alleles expressed on other IgG subclasses are warranted.

Immunoglobulin genes influence the magnitude of humoral immunity to cytomegalovirus glycoprotein B

Human cytomegalovirus (HCMV) is a risk factor for many human diseases, but among exposed individuals, not everyone is equally likely to develop HCMV-spurred diseases, implying the presence of host genetic factors that might modulate immunity to this virus. Here, we show that antibody responsiveness to HCMV glycoprotein B (gB) is significantly associated with particular immunoglobulin GM (γ marker) genotypes. Anti-HCMV gB antibody levels were highest in GM 17/17 homozygotes, intermediate in GM 3/17 heterozygotes, and lowest in GM 3/3 homozygotes (28.2, 19.0, and 8.1 µg/mL, respectively; P=.014). These findings provide mechanistic insights in the etiopathogenesis of HCMV-spurred diseases.