Expression of insulin-like growth factor binding protein-2 (IGFBP-2) gene in negative and positive human cytomegalovirus glioblastoma multiforme tissues

Presence of the Human Cytomegalovirus in Glioblastomas-A Systematic Review

Simple Summary

Whether the human cytomegalovirus (HCMV) is present in samples obtained from patients with glioblastoma (GBM) has been a matter under debate during the last two decades. Many investigators have demonstrated the presence of HCMV proteins and nucleic acids in GBM tumors, while some have not been able to detect it. It is important to evaluate current data and resolve these issues to clarify the possible role of the HCMV in GBM tumorigenesis and if this virus can serve as a potential target of therapy for these patients. In the present systematic review, we aim to review published research studies with a focus to identify differences and similarities in methods used for the detection of the HCMV in GBM samples found to be positive or negative for HCMV. Our data suggest that the HCMV is highly prevalent in glioblastomas and that optimized immunohistochemistry techniques are required to detect it.

Abstract

Glioblastoma is a malignant brain tumor with a dismal prognosis. The standard treatment has not changed in the past 15 years as clinical trials of new treatment protocols have failed. A high prevalence of the human cytomegalovirus (HCMV) in glioblastomas was first reported in 2002. The virus was found only in the tumor and not in the surrounding healthy brain tissue. Many groups have confirmed the presence of the HCMV in glioblastomas, but others could not. To resolve this discrepancy, we systematically reviewed 645 articles identified in different databases. Of these, 81 studies included results from 247 analyses of 9444 clinical samples (7024 tumor samples and 2420 blood samples) by different techniques, and 81 articles included 191 studies that identified the HCMV in 2529 tumor samples (36% of all tumor samples). HCMV proteins were often detected, whereas HCMV nucleic acids were not reliably detected by PCR methods. Optimized immunohistochemical techniques identified the virus in 1391 (84,2%) of 1653 samples. These data suggest that the HCMV is highly prevalent in glioblastomas and that optimized immunohistochemistry techniques are required to detect it.

Expression of genes encoding IGF1, IGF2, and IGFBPs in blood of obese adolescents with insulin resistance

OBJECTIVE

The development of obesity and its metabolic complications is associated with dys-regulation of various intrinsic mechanisms, which control basic metabolic processes via changes in the expression of numerous regulatory genes. The main goal of this work was to study the association between the expression of insulin-like growth factors (IGF1 and IGF2) and IGF-binding proteins and insulin resistance in obese adolescents for evaluation of possible contribution of these genes in development of insulin resistance.

METHODS

The expression of IGF1, IGF2, and IGFBPs mRNA was measured in blood of obese adolescents with normal insulin sensitivity and insulin resistance in comparison with the normal (control) individuals.

RESULTS

In the blood of obese adolescents with normal insulin sensitivity the expression of IGFBP4, IGFBP5 and HTRA1 genes was down-regulated, but IGFBP2 and IGFBP7 genes up-regulated as compared to control (normal) group. At the same time, no significant changes in IGF1 and IGF2 gene expressions in this group of obese adolescents were found. Insulin resistance in obese adolescents led to up-regulation of IGF2, IGFBP2, and IGFBP7 gene expressions as well as to down-regulation of the expression of IGF1, IGFBP5 and HTRA1 genes in the blood in comparison with the obese patients, which have normal insulin sensitivity. Furthermore, the level of IGFBP4 gene expression was similar in both groups of obese adolescents.

CONCLUSIONS

Results of this investigation provide evidence that insulin resistance in obese adolescents is associated with gene specific changes in the expression of IGF1, IGF2, IGFBP2, IGFBP5, IGFBP7, and HTRA1 genes and these changes possibly contribute to the development of glucose intolerance and insulin resistance.

Design, Synthesis, and Preliminary Studies of Spiro-isoxazoline-peroxides against Human Cytomegalovirus and Glioblastoma ∥

The association between glioblastoma (GBM) and human cytomegalovirus (HCMV) infection has been the intensely debated topic over the decades for developing new therapeutic options. In this regard, the peroxides from natural and synthetic sources served as potential antiviral and anticancer agents in the past. Herein, a concise and efficient strategy has been demonstrated to access a novel class of peroxides containing a spiro-isoxazoline to primarily investigate the biological activities. The synthetic compounds were evaluated for in vitro antiviral and antiproliferative activity against HCMV and glioblastoma cell line (GBM6), respectively. While compound 13m showed moderate anti-CMV activity (IC₅₀ = 19 μM), surprisingly, an independent biological assay for compound 13m revealed its antiproliferative activity against the human glioblastoma cell line (GBM6) with an IC₅₀ of 10 μM. Hence, the unification of an isoxazoline and peroxide heterocycles could be a potential direction to initiate the HCMV-GBM drug discovery program.

Genipin induces cell death via intrinsic apoptosis pathways in human glioblastoma cells

Genipin, a compound derived from Gardenis jasminoides Ellis fruits, was demonstrated to be the specific uncoupling protein 2 (UCP2) inhibitor. UCP2 is a mitochondrial carrier protein that creates proton leaks across the inner mitochondrial membrane, thus uncoupling oxidative phosphorylation from adenosine triphosphate (ATP) synthesis. Several studies revealed that UCP2 is broadly over-expressed in leukemia, colorectal, lung, ovarian, prostate, testicular, and bladder cancers. However, the effect of genipin still needs to be elucidated in neurological malignancies. In this study, we investigated the anticancer effect of genipin in U87MG and A172 cell lines. The anticancer effect of genipin on these cell lines was measured by microculture tetrazoliumtest (MTT), Trypan blue exclusion, and colony formation assays, in the presence of various concentrations of genipin at different time intervals. We assessed apoptosis and measure intracellular reactive oxygen species (ROS) by flow cytometry. Expression of UCP2 and some of the genes involved in apoptosis was analyzed by real-time quantitative polymerase chain reaction (PCR). Results of the MTT assay showed that genipin moderately reduced metabolic activity of both cell lines in dose- and time-dependent manner. Result of Trypan blue exclusion test indicated that the viable cell count decreased in the treated group in a concentration-dependent manner. Genipin also significantly decreased colony formation ability of these cells in a concentration-dependent manner. Result of morphological changes showed that there were significant differences in cell number and morphology in treated groups as compared with the untreated groups. Flow cytometric analysis of U87MG and A172 cells with annexin V/propidium iodide staining, 48 hours after treatment with genipin, displays 22.4% and 26.1% apoptotic population, respectively, in treated cells, in comparison to 7.42% and 9.31% apoptotic cells of untreated cells. After treatment, UCP2 and B-cell lymphoma 2 (BCL ₂ ) genes are downregulated, and BCL ₂ associated X protein, BCL ₂ antagonist/killer, BCL ₂ interacting killer, and Cytochrome c genes are upregulated. Genipin treatment increased mitochondrial ROS levels and also induced apoptosis through caspase-3 upregulation. In conclusion, the antiproliferative effects of genipin on the growth of both glioblastoma cell lines have been shown in all of these assays, and genipin profoundly induced apoptosis in both cell lines via the UCP2-related mitochondrial pathway through the induction of intracellular ROS.

Downregulation of CD147 induces malignant melanoma cell apoptosis via the regulation of IGFBP2 expression

Cluster of differentiation (CD)147, as a transmembrane glycoprotein, is highly expressed in a variety of tumors. Accumulating evidence has demonstrated that CD147 serves critical roles in tumor cell death and survival; however, the underlying mechanism requires further investigation. In the present study, it was revealed that CD147 knockdown significantly increased melanoma cell apoptosis. In addition, downregulation of CD147 reversed the malignant phenotype of melanoma, as demonstrated by the induction of tumor cell apoptosis in a xenograft mouse model. In addition, a human apoptosis antibody array was performed and 9 differentially expressed apoptosis-related proteins associated with CD147 were identified, including insulin-like growth factor-binding protein 2 (IGFBP2). Additionally, CD147 knockdown was observed to significantly decreased IGFBP2 expression at the mRNA and protein levels in melanoma cells. Providing that IGFBP2 is a downstream molecule in the phosphatase and tensin homolog (PTEN)/phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway, the effects of CD147 on this particular pathway were investigated. Interestingly, the expression of phosphorylated (p)-AKT and p‑mechanistic target of rapamycin was attenuated, whereas PTEN was markedly upregulated in CD147-underexpressing melanoma cells. Furthermore, application of a PI3K‑specific inhibitor also decreased IGFBP2 expression. Importantly, IGFBP2 was highly expressed in clinical tissues of melanoma compared with the control group, and its expression exhibited a positive association with CD147. The present study revealed that CD147 served a critical role in mediating the apoptosis of melanoma cells via IGFBP2 and the PTEN/PI3K/AKT signaling pathway. IGFBP2 and CD147 were observed to be overexpressed in clinical melanoma tissues; IGFBP2 was shown to be positively associated with CD147 expression, suggesting that CD147 may be considered as a potential therapeutic target for chemotherapy or prevention for in melanoma.

New extracellular factors in glioblastoma multiforme development: neurotensin, growth differentiation factor-15, sphingosine-1-phosphate and cytomegalovirus infection

Recent years have seen considerable progress in understanding the biochemistry of cancer. For example, more significance is now assigned to the tumor microenvironment, especially with regard to intercellular signaling in the tumor niche which depends on many factors secreted by tumor cells. In addition, great progress has been made in understanding the influence of factors such as neurotensin, growth differentiation factor-15 (GDF-15), sphingosine-1-phosphate (S1P), and infection with cytomegalovirus (CMV) on the 'hallmarks of cancer' in glioblastoma multiforme. Therefore, in the present work we describe the influence of these factors on the proliferation and apoptosis of neoplastic cells, cancer stem cells, angiogenesis, migration and invasion, and cancer immune evasion in a glioblastoma multiforme tumor. In particular, we discuss the effect of neurotensin, GDF-15, S1P (including the drug FTY720), and infection with CMV on tumor-associated macrophages (TAM), microglial cells, neutrophil and regulatory T cells (T_reg), on the tumor microenvironment. In order to better understand the role of the aforementioned factors in tumoral processes, we outline the latest models of intratumoral heterogeneity in glioblastoma multiforme. Based on the most recent reports, we discuss the problems of multi-drug therapy in treating glioblastoma multiforme.

A GLO10 score for the prediction of prognosis in high grade gliomas

Gliomas are the most common lethal brain tumours and remain great heterogeneity in terms of histopathology and clinical outcomes. Among them, glioblastomas are the most aggressive tumours that lead to a median of less than one-year survival in patients. Despite the little improvement of in diagnosis and treatments for last decades, there is an urgent need for prognostic markers to distinguish high- and low-risk patients before treatment.Here, we generated a list of genes associated with glioblastoma progressions and then performed a comprehensive statistical modelling strategy to derive a 10-gene (GLO10) score from genome wide expression profiles of a large glioblastoma cohort (n=844). Our study demonstrated that the GLO10 score could successfully distinguish high- and low-risk patients with glioblastomas regardless their traditional pathological factors. Validated in four independent cohorts, the utility of GLO10 score could provide clinicians a robust prognostic prediction tool to assess risk levels upfront treatments.

Investigation of serum levels and tissue expression of two genes IGFBP-2 and IGFBP-3 act as potential biomarker for predicting the progression and survival in patients with glioblastoma multiforme

BACKGROUND

Identification of genetic copy number changes in glial tumors is of importance in the context of improved/refined diagnostic, prognostic procedures and therapeutic decision-making. Blood-derived biomarkers, therefore, would be useful as minimally invasive markers that could support diagnosis and enable monitoring of tumour growth and response to treatment.

OBJECTIVE

The aim of this study was to evaluate the clinical significance of IGFBP-2/3 in glioblastoma multiforme (GBM) and their value as predictors of survival.

METHODS

We examined the plasma levels of IGFBP-2 and IGFBP-3 using ELISA in patient suffering from GBM and controls groups. Furthermore, immunohistochemistry method was used to evaluate the expression levels of these markers.

RESULTS

Preoperative plasma levels of IGFBP-2 and IGFBP-3 were markedly higher in glioblastoma patients (mean±SD: 521.5±164.2ng/ml; 402.4±126ng/ml) when compared with healthy controls (301.28±73.12; 244±89.5ng/ml; p<0.001). Immunohistochemical results indicated that the median H score for glioblastoma tissues was higher when compared with normal tissues. The mean scores for IGFBP-2 expression in glioblastoma was higher than normal tissues (p<0.001). Our result showed that the median H score for glioblastoma tissues was higher when compared with normal tissue for IGFBP-3 expression. The mean scores for glioblastoma tissues was higher than normal tissues (p<0.001). We also evaluated whether plasma IGFBP-2 and IGFBP-3 levels were related to clinical features. The plasma IGFBP-2 level was strongly linked to the patient's age (R=0.769, P=0.001) that were strongly increased in patients with older age (>65), (mean±SD: 594.36±33.3ng/ml). On the other hand, plasma IGFBP-3 level was not correlated with age (P=0.462), sex (P=0.532), and tumor size (P=0.245). Our findings indicated that the tissue IGFBP-2 level was also markedly correlated with the patient's age (R=0.612, P=0.015). On the other hand, tissue IGFBP-3 expression level was not correlated with age (P=0.472), sex (P=0.512), and tumor size (P=0.241). Kaplan-Meier survival and log-rank analysis suggested that patients with high plasma level of IGFBP-2 and tissue expression of IGFBP-2 had shorter overall survival than those with low levels (log-rank test P=0.027; P<0.001). Kaplan-Meier survival and log-rank analysis suggested that patients with high plasma level of IGFBP-3 and tissue expression of IGFBP-3 had shorter overall survival than those with low levels groups (log-rank test P=0.018; P<0.001).

CONCLUSION

These data suggest that plasma levels and tissue levels of IGFBP-2 and IGFBP-3 may be as potential biomarkers for predicting the progression and survival in patients with GBM.

IGF-binding protein 2 is a candidate target of therapeutic potential in cancer

Insulin-like growth factor (IGF)-binding protein 2(IGFBP2), a key member of IGF family, has been reported as a notable oncogene in most human epithelium cancers. Increasing evidences suggested that IGFBP2 might be a candidate target of therapuetic potential by regulating key cancer metastasis and invasion-associated signaling networks, but there is still confusion about the mechanism on how IGFBP2 takes part in these processes. In this review, we summarized the current points of view that IGFBP2 functions in signaling pathways during tumorigenesis and tumor progression and discussed its potential clinical applications as a therapeutic target.

Overexpression of enhancer of zeste human homolog 2 (EZH2) gene in human cytomegalovirus positive glioblastoma multiforme tissues

Glioblastoma multiforme (GBM) is considered to be one of the most invasive human cancers, characterized by a high mortality rate and an average survival is <1 year. These tumors are highly aggressive and insensitive to conventional radio and chemotherapy. An interesting aspect of glioblastoma is the association of active human cytomegalovirus (HCMV) infection, which is evident by the presence of viral DNA, mRNA and protein level in most glioblastoma tissues. Although the presence of the HCMV infection in glioblastoma is well established, but the oncomodulatory role of HCMV is not defined yet. Enhancer of zeste human homolog 2 (EZH2) is a key protein of the polycomb repressive complex 2, epigenetic gene silencers. There have been several reports that EZH2 activity is essential in GBM pathogenesis. In our previous research, we have found a high rate of HCMV infection in a cohort of Iranian glioblastoma patients. In this study, we investigated the expression of EZH2 in HCMV-negative versus HCMV-positive GBM tissues in comparison to non-tumor tissues. The level of expression was determined by real time PCR and the differences were calculated using the Livac or 2(-ΔΔCt) and analysis of variance (ANOVA). Relative expression of EZH2 in HCMV-negative glioblastoma tissues were increased 6.053-fold compared to non-neoplastic brain tissues, while EZH2 gene expression was increased 41.098-fold in HCMV-positive glioblastoma tissues. ANOVA test showed that there is a significant difference in EZH2 expression between normal brain tissue, HCMV-negative and HCMV-positive glioblastoma tumors (p value = 0.0001). Our data indicate that EZH2 expression can be considered a risk factor in glioblastoma and EZH2 inhibitors may serve as potential new treatment in glioblastoma. This would be an interesting new field to investigate in more detail.

Control of IGFBP-2 Expression by Steroids and Peptide Hormones in Vertebrates

IGFBP-2 (1) has been described as a brain tumor oncogene (2) and is widely expressed in cancers from different origins (3-8). IGFBP-2 alone cannot cause malignant transformation, yet progression of brain tumors to higher grade (9) and also has been provided as a protective element in earlier stages of multistage colon carcinogenesis (10). Therefore, it is crucial to understand the factors that determine expression patterns of IGFBP-2 under normal and malignant conditions. The present review provides a comprehensive update of known factors that have an impact on expression of IGFBP-2.