Grade-Specific Expression of Insulin-like Growth Factor–Binding Proteins-2, -3, and -5 in Astrocytomas: IGFBP-3 Emerges as a Strong Predictor of Survival in Patients with Newly Diagnosed Glioblastoma

mRNA markers for survival prediction in glioblastoma multiforme patients: a systematic review with bioinformatic analyses

BACKGROUND

Glioblastoma multiforme (GBM) is a type of fast-growing brain glioma associated with a very poor prognosis. This study aims to identify key genes whose expression is associated with the overall survival (OS) in patients with GBM.

METHODS

A systematic review was performed using PubMed, Scopus, Cochrane, and Web of Science up to Journey 2024. Two researchers independently extracted the data and assessed the study quality according to the New Castle Ottawa scale (NOS). The genes whose expression was found to be associated with survival were identified and considered in a subsequent bioinformatic study. The products of these genes were also analyzed considering protein-protein interaction (PPI) relationship analysis using STRING. Additionally, the most important genes associated with GBM patients' survival were also identified using the Cytoscape 3.9.0 software. For final validation, GEPIA and CGGA (mRNAseq_325 and mRNAseq_693) databases were used to conduct OS analyses. Gene set enrichment analysis was performed with GO Biological Process 2023.

RESULTS

From an initial search of 4104 articles, 255 studies were included from 24 countries. Studies described 613 unique genes whose mRNAs were significantly associated with OS in GBM patients, of which 107 were described in 2 or more studies. Based on the NOS, 131 studies were of high quality, while 124 were considered as low-quality studies. According to the PPI network, 31 key target genes were identified. Pathway analysis revealed five hub genes (IL6, NOTCH1, TGFB1, EGFR, and KDR). However, in the validation study, only, the FN1 gene was significant in three cohorts.

CONCLUSION

We successfully identified the most important 31 genes whose products may be considered as potential prognosis biomarkers as well as candidate target genes for innovative therapy of GBM tumors.

Clinicopathological and molecular landscape of 5-year IDH-wild-type glioblastoma survivors: A multicentric retrospective study

Five-year glioblastoma (GBM) survivors (LTS) are the minority of the isocitrate dehydrogenase (IDH)-wild-type GBM patients, and their molecular fingerprint is still largely unexplored. This multicenter retrospective study analyzed a large LTS-GBM cohort from nine Italian institutions and molecularly characterized a subgroup of patients by mutation, DNA methylation (DNAm) and copy number variation (CNV) profiling, comparing it to standard survival GBM. Mutation scan allowed the identification of pathogenic variants in most cases, showing a similar mutational spectrum in both groups, and highlighted TP53 as the most commonly mutated gene in the LTS group. We confirmed DNAm as a valuable tool for GBM classification with a diagnostic refinement by using brain tumor classifier v12.5. LTS were more heterogeneous with more cases classified as diffuse pediatric high-grade glioma subtypes and having peculiar CNVs. We observed a global higher methylation in CpG islands and in gene promoters of LTS with methylation levels of distinct gene promoters correlating with prognosis.

Gene Expression Patterns Associated with Survival in Glioblastoma

The aim of this study was to investigate gene expression alterations associated with overall survival (OS) in glioblastoma (GBM). Using the Nanostring nCounter platform, we identified four genes (COL1A2, IGFBP3, NGFR, and WIF1) that achieved statistical significance when comparing GBM with non-neoplastic brain tissue. The four genes were included in a multivariate Cox Proportional Hazard model, along with age, extent of resection, and O6-methylguanine-DNA methyltransferase (MGMT) promotor methylation, to create a unique glioblastoma prognostic index (GPI). The GPI score inversely correlated with survival: patient with a high GPI had a median OS of 7.5 months (18-month OS = 9.7%) whereas patients with a low GPI had a median OS of 20.1 months (18-month OS = 54.5%; log rank p-value = 0.004). The GPI score was then validated in 188 GBM patients from The Cancer Genome Atlas (TCGA) from a national data base; similarly, patients with a high GPI had a median OS of 10.5 months (18-month OS = 12.4%) versus 16.9 months (18-month OS = 41.5%) for low GPI (log rank p-value = 0.0003). We conclude that this novel mRNA-based prognostic index could be useful in classifying GBM patients into risk groups and refine prognosis estimates to better inform treatment decisions or stratification into clinical trials.

IGFBP3 induced by the TGF-β/EGFRvIII transactivation contributes to the malignant phenotype of glioblastoma

Dual or multi-targets therapy targeting epidermal growth factor receptor variant III (EGFRvIII) and other molecular may relax the constraint for glioblastoma (GBM), putting forward the urgent requirement of finding candidate molecules. Here, the insulin-like growth factor binding protein-3 (IGFBP3) was considered a candidate, whereas the mechanisms of IGFBP3 production remain unclear. We treated GBM cells with exogenous transforming growth factor β (TGF-β) to simulate the microenvironment. We found that TGF-β and EGFRvIII transactivation induced the activation of transcription factor c-Jun, which specifically bound to the promoter region of IGFBP3 through Smad2/3 and ERK1/2 pathways and promoted the production and secretion of IGFBP3. IGFBP3 knockdown inhibited the activation of TGF-β and EGFRvIII signals and the malignant behaviors triggered by them in vitro and in vivo. Collectively, our results indicated a positive feedback loop of p-EGFRvIII/IGFBP3 under administration of TGF-β, blocking IGFBP3 may be an additional target in EGFRvIII-expressing GBM-selective therapeutic strategy.

IGFBP5 is an ROR1 ligand promoting glioblastoma invasion via ROR1/HER2-CREB signaling axis

Diffuse infiltration is the main reason for therapeutic resistance and recurrence in glioblastoma (GBM). However, potential targeted therapies for GBM stem-like cell (GSC) which is responsible for GBM invasion are limited. Herein, we report Insulin-like Growth Factor-Binding Protein 5 (IGFBP5) is a ligand for Receptor tyrosine kinase like Orphan Receptor 1 (ROR1), as a promising target for GSC invasion. Using a GSC-derived brain tumor model, GSCs were characterized into invasive or non-invasive subtypes, and RNA sequencing analysis revealed that IGFBP5 was differentially expressed between these two subtypes. GSC invasion capacity was inhibited by IGFBP5 knockdown and enhanced by IGFBP5 overexpression both in vitro and in vivo, particularly in a patient-derived xenograft model. IGFBP5 binds to ROR1 and facilitates ROR1/HER2 heterodimer formation, followed by inducing CREB-mediated ETV5 and FBXW9 expression, thereby promoting GSC invasion and tumorigenesis. Importantly, using a tumor-specific targeting and penetrating nanocapsule-mediated delivery of CRISPR/Cas9-based IGFBP5 gene editing significantly suppressed GSC invasion and downstream gene expression, and prolonged the survival of orthotopic tumor-bearing mice. Collectively, our data reveal that IGFBP5-ROR1/HER2-CREB signaling axis as a potential GBM therapeutic target.

IGF-binding proteins secreted by cancer-associated fibroblasts induce context-dependent drug sensitization of lung cancer cells

Cancer-associated fibroblasts (CAFs) in the tumor microenvironment are often linked to drug resistance. Here, we found that coculture with CAFs or culture in CAF-conditioned medium unexpectedly induced drug sensitivity in certain lung cancer cell lines. Gene expression and secretome analyses of CAFs and normal lung-associated fibroblasts (NAFs) revealed differential abundance of insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs), which promoted or inhibited, respectively, signaling by the receptor IGF1R and the kinase FAK. Similar drug sensitization was seen in gefitinib-resistant, EGFR-mutant PC9GR lung cancer cells treated with recombinant IGFBPs. Conversely, drug sensitivity was decreased by recombinant IGFs or conditioned medium from CAFs in which IGFBP5 or IGFBP6 was silenced. Phosphoproteomics and receptor tyrosine kinase (RTK) array analyses indicated that exposure of PC9GR cells to CAF-conditioned medium also inhibited compensatory IGF1R and FAK signaling induced by the EGFR inhibitor osimertinib. Combined small-molecule inhibition of IGF1R and FAK phenocopied the CAF-mediated effects in culture and increased the antitumor effect of osimertinib in mice. Cells that were osimertinib resistant and had MET amplification or showed epithelial-to-mesenchymal transition also displayed residual sensitivity to IGFBPs. Thus, CAFs promote or reduce drug resistance in a context-dependent manner, and deciphering the relationship between the differential content of CAF secretomes and the signaling dependencies of the tumor may reveal effective combination treatment strategies.

Chitinase 3-Like 2

OBJECTIVES

We aimed to evaluate the expression pattern of chitinase 3-like 2 (CHI3L2) in the tumor core and peritumoral brain zone (PBZ) of newly diagnosed glioblastoma (GBM) in recurrent tumors and its association with patient prognosis.

METHODS

The study was conducted on three sample sets derived from different patient cohorts. Messenger RNA (mRNA) expression of CHI3L2 in the tumor core and PBZ (n = 34) compared with control (n = 20) tissues was studied by quantitative polymerase chain reaction in sample set 1. Sample set 2 included 19 paired, primary-recurrent GBM tissues. Sample set 3 comprised 82 GBM tissues of patients with treatment and follow-up information. Immunohistochemistry (IHC) was performed on all three sample sets.

RESULTS

mRNA expression of CHI3L2 was significantly higher in the tumor core and PBZ compared with control (P < .0001). By IHC, CHI3L2 showed strong cytoplasmic staining in tumor cells. Recurrent tumors had a higher expression of CHI3L2 compared with primary tumors (P = .007). Survival analysis showed CHI3L2 expression was associated with shorter overall survival (P = .034) and progression-free survival (P = .010), which was in line with The Cancer Genome Atlas cohort (P = .043).

CONCLUSIONS

High expression of CHI3L2 in the tumor core and PBZ, as well as its association with tumor recurrence and poor patient prognosis, suggests it might be contributing to tumor spread and recurrence.

The DNA Double-Strand Break Repair in Glioma: Molecular Players and Therapeutic Strategies

Gliomas are the most frequent type of tumor in the central nervous system, which exhibit properties that make their treatment difficult, such as cellular infiltration, heterogeneity, and the presence of stem-like cells responsible for tumor recurrence. The response of this type of tumor to chemoradiotherapy is poor, possibly due to a higher repair activity of the genetic material, among other causes. The DNA double-strand breaks are an important type of lesion to the genetic material, which have the potential to trigger processes of cell death or cause gene aberrations that could promote tumorigenesis. This review describes how the different cellular elements regulate the formation of DNA double-strand breaks and their repair in gliomas, discussing the therapeutic potential of the induction of this type of lesion and the suppression of its repair as a control mechanism of brain tumorigenesis.

Noncoding RNA actions through IGFs and IGF binding proteins in cancer

The insulin-like growth factors (IGFs) and their regulatory proteins—IGF receptors and binding proteins—are strongly implicated in cancer progression and modulate cell survival and proliferation, migration, angiogenesis and metastasis. By regulating the bioavailability of the type-1 IGF receptor (IGF1R) ligands, IGF-1 and IGF-2, the IGF binding proteins (IGFBP-1 to -6) play essential roles in cancer progression. IGFBPs also influence cell communications through pathways that are independent of IGF1R activation. Noncoding RNAs (ncRNAs), which encompass a variety of RNA types including microRNAs (miRNAs) and long-noncoding RNAs (lncRNAs), have roles in multiple oncogenic pathways, but their many points of intersection with IGF axis functions remain to be fully explored. This review examines the functional interactions of miRNAs and lncRNAs with IGFs and their binding proteins in cancer, and reveals how the IGF axis may mediate ncRNA actions that promote or suppress cancer. A better understanding of the links between ncRNA and IGF pathways may suggest new avenues for prognosis and therapeutic intervention in cancer. Further, by exploring examples of intersecting ncRNA-IGF pathways in non-cancer conditions, it is proposed that new opportunities for future discovery in cancer control may be generated.

In Silico Analysis of the Correlation of KIF2C with Prognosis and Immune Infiltration in Glioma

Glioblastoma (GBM) is one of the most commonly pivotal malignant caners. Numerous reports have revealed the crucial roles of immune infiltration in the initiation and progression of GBM. In this study, we first identified differentially expressed genes (DEGs) in the progression of GBM using CGGA databases. Totally, 156 upregulated DEGs and 251 downregulated DEGs were revealed. By constructing a protein-protein interaction network, KIF2C was identified as a hub gene in GBM. Further analysis revealed an evidently positive association existing in KIF2C expression and the advanced stages of gliomas. Higher expression of KIF2C was in WHO grade IV samples relative to that in grade III and grade II samples. In addition, our results showed that KIF2C was higher in IDH1 wild-type samples than IDH1 mutant glioma samples, in 1p/19q noncodel samples than 1p/19q code glioma samples, and in recurrent samples than primary glioma samples. Moreover, our results showed that higher expression of KIF2C correlated with shorter survival time in both primary and recurrent gliomas and could act as a potential biomarker for the prognosis of GBM. Further analysis demonstrated that higher expression of KIF2C was related to higher levels of endothelial cell, T cell CD8+ naïve, common lymphoid progenitor, T cell CD4+ Th2, T cell CD4+ Th2, macrophage, macrophage M1, T cell CD4+ memory, and T cell CD4+ effector memory, but was related to lower levels of NK cell, B cell plasma, T cell CD4+ Th1, T cell regulatory (Tregs), neutrophil, and T cell NK. We thought this study could provide potential biomarkers for the prediction of prognosis and immune infiltration of gliomas.

Genome-wide association study across pediatric central nervous system tumors implicates shared predisposition and points to 1q25.2 (PAPPA2) and 11p12 (LRRC4C) as novel candidate susceptibility loci

INTRODUCTION

Central nervous system (CNS) tumors constitute the most common form of solid neoplasms in children, but knowledge on genetic predisposition is sparse. In particular, whether susceptibility attributable to common variants is shared across CNS tumor types in children has not been investigated. The purpose of this study was to explore potential common genetic risk variants exhibiting pleiotropic effects across pediatric CNS tumors. We also investigated whether such susceptibility differs between early and late onset of disease.

METHOD

A Danish nationwide genome-wide association study (GWAS) of 1,097 consecutive patients (< 15 years of age) with CNS tumors and a cohort of 4,745 population-based controls.

RESULTS

For both the overall cohort and patients diagnosed after the age of four, the strongest association was rs12064625 which maps to PAPPA2 at 1q25.2 (p = 3.400 × 10^-7 and 9.668 × 10^-8, respectively). PAPPA2 regulates local bioavailability of insulin-like growth factor I (IGF-I). IGF-I is fundamental to CNS development and is involved in tumorigenesis across a wide range of different cancers. For the younger children, the strongest association was provided by rs11036373 mapping to LRRC4C at 11p12 (p = 7.620 × 10^-7), which encoded protein acts as an axon guidance molecule during CNS development and has not formerly been associated with brain tumors.

DISCUSSION

This GWAS indicates shared susceptibility attributable to common variants across pediatric CNS tumor types. Variations in genetic loci with roles in CNS development appear to be involved, possibly via altered IGF-I related pathways.

Prognostic and Therapeutic Roles of the Insulin Growth Factor System in Glioblastoma

Glioblastoma multiforme (GBM) is the most common primary brain malignancy and is often resistant to conventional treatments due to its extensive cellular heterogeneity. Thus, the overall survival of GBM patients remains extremely poor. Insulin-like growth factor (IGF) signaling entails a complex system that is a key regulator of cell transformation, growth and cell-cycle progression. Hence, its deregulation is frequently involved in the development of several cancers, including brain malignancies. In GBM, differential expression of several IGF system components and alterations of this signaling axis are linked to significantly worse prognosis and reduced responsiveness to temozolomide, the most commonly used pharmacological agent for the treatment of the disease. In the present review we summarize the biological role of the IGF system in the pathogenesis of GBM and comprehensively discuss its clinical significance and contribution to the development of resistance to standard chemotherapy and experimental treatments.

Congress of neurological surgeons systematic review and evidence-based guidelines update on the role of emerging developments in the management of newly diagnosed glioblastoma

TARGET POPULATION

These recommendations apply to adult patients with newly diagnosed or suspected glioblastoma.

IMAGING

Question What imaging modalities are in development that may be able to provide improvements in diagnosis, and therapeutic guidance for individuals with newly diagnosed glioblastoma?

RECOMMENDATION

Level III: It is suggested that techniques utilizing magnetic resonance imaging for diffusion weighted imaging, and to measure cerebral blood and magnetic spectroscopic resonance imaging of N-acetyl aspartate, choline and the choline to N-acetyl aspartate index to assist in diagnosis and treatment planning in patients with newly diagnosed or suspected glioblastoma.

SURGERY

Question What new surgical techniques can be used to provide improved tumor definition and resectability to yield better tumor control and prognosis for individuals with newly diagnosed glioblastoma?

RECOMMENDATIONS

Level II: The use of 5-aminolevulinic acid is recommended to improve extent of tumor resection in patients with newly diagnosed glioblastoma. Level II: The use of 5-aminolevulinic acid is recommended to improve median survival and 2 year survival in newly diagnosed glioblastoma patients with clinical characteristics suggesting poor prognosis. Level III: It is suggested that, when available, patients be enrolled in properly designed clinical trials assessing the value of diffusion tensor imaging in improving the safety of patients with newly diagnosed glioblastoma undergoing surgery.

NEUROPATHOLOGY

Question What new pathology techniques and measurement of biomarkers in tumor tissue can be used to provide improved diagnostic ability, and determination of therapeutic responsiveness and prognosis for patients with newly diagnosed glioblastomas?

RECOMMENDATIONS

Level II: Assessment of tumor MGMT promoter methylation status is recommended as a significant predictor of a longer progression free survival and overall survival in patients with newly diagnosed with glioblastoma. Level II: Measurement of tumor expression of neuron-glia-2, neurofilament protein, glutamine synthetase and phosphorylated STAT3 is recommended as a predictor of overall survival in patients with newly diagnosed with glioblastoma. Level III: Assessment of tumor IDH1 mutation status is suggested as a predictor of longer progression free survival and overall survival in patients with newly diagnosed with glioblastoma. Level III: Evaluation of tumor expression of Phosphorylated Mitogen-Activated Protein Kinase protein, EGFR protein, and Insulin-like Growth Factor-Binding Protein-3 is suggested as a predictor of overall survival in patients with newly diagnosed with glioblastoma.

RADIATION

Question What radiation therapy techniques are in development that may be used to provide improved tumor control and prognosis for individuals with newly diagnosed glioblastomas?

RECOMMENDATIONS

Level III: It is suggested that patients with newly diagnosed glioblastoma undergo pretreatment radio-labeled amino acid tracer positron emission tomography to assess areas at risk for tumor recurrence to assist in radiation treatment planning. Level III: It is suggested that, when available, patients be with newly diagnosed glioblastomas be enrolled in properly designed clinical trials of radiation dose escalation, altered fractionation, or new radiation delivery techniques.

CHEMOTHERAPY

Question What emerging chemotherapeutic agents or techniques are available to provide better tumor control and prognosis for patients with newly diagnosed glioblastomas?

RECOMMENDATION

Level III: As no emerging chemotherapeutic agents or techniques were identified in this review that improved tumor control and prognosis it is suggested that, when available, patients with newly diagnosed glioblastomas be enrolled in properly designed clinical trials of chemotherapy.

MOLECULAR AND TARGETED THERAPY

Question What new targeted therapy agents are available to provide better tumor control and prognosis for individuals with newly diagnosed glioblastomas?

RECOMMENDATION

Level III: As no new molecular and targeted therapies have clearly provided better tumor control and prognosis it is suggested that, when available, patients with newly diagnosed glioblastomas be enrolled in properly designed clinical trials of molecular and targeted therapies IMMUNOTHERAPY: Question What emerging immunotherapeutic agents or techniques are available to provide better tumor control and prognosis for patients with newly diagnosed glioblastomas?

RECOMMENDATION

Level III: As no immunotherapeutic agents have clearly provided better tumor control and prognosis it is suggested that, when available, patients with newly diagnosed glioblastomas be enrolled in properly designed clinical trials of immunologically-based therapies.

NOVEL THERAPIES

Question What novel therapies or techniques are in development to provide better tumor control and prognosis for individuals with newly diagnosed glioblastomas?

RECOMMENDATIONS

Level II: The use of tumor-treating fields is recommended for patients with newly diagnosed glioblastoma who have undergone surgical debulking and completed concurrent chemoradiation without progression of disease at the time of tumor-treating field therapy initiation. Level II: It is suggested that, when available, enrollment in properly designed studies of vector containing herpes simplex thymidine kinase gene and prodrug therapies be considered in patients with newly diagnosed glioblastoma.

MN1 overexpression with varying tumor grade is a promising predictor of survival of glioma patients

Gliomas have substantial mortality to incidence rate ratio and a dismal clinical course. Newer molecular insights, therefore, are imperative to refine glioma diagnosis, prognosis and therapy. Meningioma 1 (MN1) gene is a transcriptional co-regulator implicated in other malignancies, albeit its significance in glioma pathology remains to be explored. IGFBP5 is regulated transcriptionally by MN1 and IGF1 and is associated with higher glioma grade and shorter survival time, prompting us to ascertain their correlation in these tumors. We quantified the expression of MN1, IGFBP5 and IGF1 in 40 glioma samples and examined their interrelatedness. MN1 mRNA-protein inter-correlation and the gene’s copy number were evaluated in these tumors. Publicly available TCGA datasets were used to examine the association of MN1 expression levels with patient survival and for validating our findings. We observed MN1 overexpression correlated with low-grade (LGGs) and not high-grade gliomas and is not determined by the copy number alteration of the gene. Notably, gliomas with upregulated MN1 have better overall survival (OS) and progression-free survival (PFS). IGFBP5 expression associated inversely with MN1 expression levels in gliomas but correlated positively with IGF1 expression in only LGGs. This suggests a potential grade-specific interplay between repressive and activating roles of MN1 and IGF1, respectively, in the regulation of IGFBP5. Thus, MN1 overexpression, a promising predictor of OS and PFS in gliomas, may serve as a prognostic biomarker in clinical practice to categorize patients with survival advantage.

Low mitochondrial DNA copy number is associated with poor prognosis and treatment resistance in glioblastoma

INTRODUCTION

Mitochondrial DNA (mtDNA) content in several solid tumors was found to be lower than in their normal counterparts. However, there is paucity of literature on the clinical significance of mtDNA content in glioblastoma and its effect on treatment response. Hence, we studied the prognostic significance of mtDNA content in glioblastoma tumor tissue and the effect of mtDNA depletion in glioblastoma cells on response to treatment.

MATERIALS AND METHODS

130 newly diagnosed glioblastomas, 32 paired newly diagnosed and recurrent glioblastomas and 35 non-neoplastic brain tissues were utilized for the study. mtDNA content in the patient tumor tissue was assessed and compared with known biomarkers and patient survival. mtDNA was chemically depleted in malignant glioma cell lines, U87, LN229. The biology and treatment response of parent and depleted cells were compared.

RESULTS

Lower range of mtDNA copy number in glioblastoma was associated with poor overall survival (p = 0.01), progression free survival (p = 0.04) and also with wild type IDH (p = 0.02). In recurrent glioblastoma, mtDNA copy number was higher than newly diagnosed glioblastoma in the patients who received RT (p = 0.01). mtDNA depleted U87 and LN229 cells showed higher survival fraction post radiation exposure when compared to parent lines. The IC50 of TMZ was also higher for mtDNA depleted U87 and LN229 cells. The depleted cells formed more neurospheres than their parent counterparts, thus showing increased stemness of mtDNA depleted cells.

CONCLUSION

Low mtDNA copy number in glioblastoma is associated with poor patient survival and treatment resistance in cell lines possibly by impacting stemness of the glioblastoma cells.

Enhanced Expression of IGFBP-3 Reduces Radiosensitivity and Is Associated with Poor Prognosis in Oral Squamous Cell Carcinoma

Insulin-like growth factor (IGF) binding protein-3 (IGFBP-3) modulates various cell functions through IGF-dependent or independent mechanisms. However, its biological roles in the radiosensitivity of oral squamous cell carcinoma (OSCC) remain largely unknown. The purpose of this study was to determine the clinical significance and molecular mechanisms of the association between IGFBP-3 and OSCC radiosensitivity. We performed an immunohistochemical analysis of IGFBP-3 in 52 OSCC specimens from patients treated with preoperative chemoradiotherapy and surgery (phase II study). Associations between IGFBP-3 expression and clinicopathological features were also evaluated. In addition, we examined the effects of IGFBP-3 on post-X-ray irradiation radiosensitivity and DNA damage in vitro. High IGFBP-3 expression was significantly correlated with poor chemoradiotherapy responses and prognosis. With IGFBP-3 knockdown, irradiated OSCC cells exhibited significantly higher radiosensitivity compared with that of control cells. Moreover, IGFBP-3 depletion in OSCC cells reduced phosphorylation of the DNA-dependent protein kinase catalytic subunit (DNA-PKcs), which is required for DNA double-strand break repair during non-homologous end joining. These findings indicate that IGFBP-3 may have a significant role in regulating DNA repair and is be a potential biomarker for predicting clinical response to radiotherapy and prognosis in OSCC.

Sphingosine-1-Phosphate in the Tumor Microenvironment: A Signaling Hub Regulating Cancer Hallmarks

As a key hub of malignant properties, the cancer microenvironment plays a crucial role intimately connected to tumor properties. Accumulating evidence supports that the lysophospholipid sphingosine-1-phosphate acts as a key signal in the cancer extracellular milieu. In this review, we have a particular focus on glioblastoma, representative of a highly aggressive and deleterious neoplasm in humans. First, we highlight recent advances and emerging concepts for how tumor cells and different recruited normal cells contribute to the sphingosine-1-phosphate enrichment in the cancer microenvironment. Then, we describe and discuss how sphingosine-1-phosphate signaling contributes to favor cancer hallmarks including enhancement of proliferation, stemness, invasion, death resistance, angiogenesis, immune evasion and, possibly, aberrant metabolism. We also discuss the potential of how sphingosine-1-phosphate control mechanisms are coordinated across distinct cancer microenvironments. Further progress in understanding the role of S1P signaling in cancer will depend crucially on increasing knowledge of its participation in the tumor microenvironment.

Effects of IGFBP-3 and GalNAc-T14 on proliferation and cell cycle of glioblastoma cells and its mechanism

OBJECTIVE

The purpose of this study was to determine the effects of IGFBP-3 and GalNAc-T14 on the proliferation and cell cycle of glioblastoma cells and to explore the mechanisms of action.

METHODS

U87MG and U251MG glioblastoma cells were treated with recombinant human IGFBP-3 (rhIGFBP-3). Furthermore, IGFBP-3-overexpressed cells and cells co-overexpressing IGFBP-3 and GalNAc-T14 were constructed by transfection. Cell viability, cell colony formation ability, cell cycle and protein expression were determined by MTT assay, colony formation assay, flow cytometry and Western blotting, respectively.

KEY FINDINGS

Both rhIGFBP-3 treatment and overexpression of IGFBP-3 induced the proliferation, colony formation, and G1/S phase transformation of U87MG and U251MG cells. In addition, the expression of cyclinE, CDK2 and p-ERK1/2 proteins was up-regulated in the cells. In cells co-overexpressing, IGFBP-3 and GalNAc-T14, cell proliferation, colony formation and G1/S phase transformation were inhibited, and the expression of CyclinE, CDK2 and p-ERK1/2 was significantly down-regulated, when compared with IGFBP-3-overexpressed cells.

CONCLUSIONS

IGFBP-3 can promote the proliferation, colony formation and G1/S phase transformation of U87MG and U251MG cells, which may be related to the activation of ERK signalling pathway and the up-regulation of cyclinE and CDK2 proteins. Furthermore, our study demonstrated that GalNAc-T14 can inhibit the functions of IGFBP-3.

Recurrent Glioblastomas Exhibit Higher Expression of Biomarkers with Stem-like Properties

Background

Despite advances in the treatment of glioblastoma (GBM), the prognosis of patients continues to remain dismal. This unfavorable prognosis is mainly attributed to the tumor's propensity for progression and recurrence, which in turn is due to the highly aggressive nature of the persisting GBM cells that actively egress from the main tumor mass into the surrounding normal brain tissue. Such a recurrent tumor described to have a more malignant potential is highly invasive and resistant to current therapies, probably due to increased stemness and preferential selection of therapy-resistant clones of tumor cells. However, there is a paucity of literature on the expression of biomarkers in the recurrent GBM tumors that could have a role in conferring this aggressiveness.

Aim

To identify the differences in the expression pattern of selected biomarkers in paired tissue samples of GBM.

Material and Methods

A retrospective study on 30 paired samples of GBM (newly diagnosed/primary and recurrent) archived in the Department of Neuropathology, NIMHANS (2006-2009), was carried out. After obtaining clinical and demographic details, tumors were characterized histomorphologically and immunohistochemically on formalin-fixed paraffin-embedded tissues with reference to expression of biomarkers such as p53, epidermal growth factor receptor (EGFR), insulin-like growth factor binding protein 3 (IGFBP-3), sex determining region Y-box 2 (SOX2), and topoisomerase 2 A (Top2A). The results were statistically analyzed.

Results

It was observed that while p53 and IGFBP-3 expression remained unaltered in paired samples, a significant increase in the expression of EGFR (P < 0.01) was noted in the recurrent tumors. Among the other biomarkers, SOX2 expression was higher in the recurrent tumors when compared to the primary tumors (P < 0.01). Conversely, the expression of Top2A was reduced in recurrent tumors (P = 0.05). Mild elevation in the expression of IGFBP-3 was observed in recurrent tumors but was not statistically significant.

Conclusion

A significant increase in the expression of SOX2 in recurrent tumors probably indicates the presence of undifferentiated cells with stem-like properties in these tumors. EGFR is known to mediate SOX2 expression thereby resulting in stemness of the glioma cancer cells, which could further explain its overexpression in recurrent GBMs. Furthermore, a decreased expression of TOP2A observed in the recurrent tumors could probably be due to reduction in chemosensitivity to temozolomide, which has been shown in earlier studies. We also noted that p53 expression remained unaltered in the recurrent tumors when compared to the primary, suggesting the absence of preferential clonal expansion of p53 mutant cells following exposure to radiochemotherapy. Our study reiterates the fact that GBM recurrences are associated with molecular alterations that probably contribute to radiochemoresistance, increased invasiveness, therapeutic efficacy, and stemness.

Identification of Crucial Candidate Genes and Pathways in Glioblastoma Multiform by Bioinformatics Analysis

The present study aimed to investigate the molecular mechanisms underlying glioblastoma multiform (GBM) and its biomarkers. The differentially expressed genes (DEGs) were diagnosed using the limma software package. The ToppGene (ToppFun) was used to perform pathway and Gene Ontology (GO) enrichment analysis of the DEGs. Protein-protein interaction (PPI) networks, extracted modules, miRNA-target genes regulatory network and TF-target genes regulatory network were used to obtain insight into the actions of DEGs. Survival analysis for DEGs was carried out. A total of 590 DEGs, including 243 up regulated and 347 down regulated genes, were diagnosed between scrambled shRNA expression and Lin7A knock down. The up-regulated genes were enriched in ribosome, mitochondrial translation termination, translation, and peptide biosynthetic process. The down-regulated genes were enriched in focal adhesion, VEGFR3 signaling in lymphatic endothelium, extracellular matrix organization, and extracellular matrix. The current study screened the genes in the PPI network, extracted modules, miRNA-target genes regulatory network, and TF-target genes regulatory network with higher degrees as hub genes, which included NPM1, CUL4A, YIPF1, SHC1, AKT1, VLDLR, RPL14, P3H2, DTNA, FAM126B, RPL34, and MYL5. Survival analysis indicated that the high expression of RPL36A and MRPL35 were predicting longer survival of GBM, while high expression of AP1S1 and AKAP12 were predicting shorter survival of GBM. High expression of RPL36A and AP1S1 were associated with pathogenesis of GBM, while low expression of ALPL was associated with pathogenesis of GBM. In conclusion, the current study diagnosed DEGs between scrambled shRNA expression and Lin7A knock down samples, which could improve our understanding of the molecular mechanisms in the progression of GBM, and these crucial as well as new diagnostic markers might be used as therapeutic targets for GBM.

Use of Genome-Scale Integrated Analysis to Identify Key Genes and Potential Molecular Mechanisms in Recurrence of Lower-Grade Brain Glioma

Background

The aim of this study was to identify gene signals for lower-grade glioma (LGG) and to assess their potential as recurrence biomarkers.

Material/Methods

An LGG-related mRNA sequencing dataset was downloaded from The Cancer Genome Atlas (TCGA) Informix. Multiple bioinformatics analysis methods were used to identify key genes and potential molecular mechanisms in recurrence of LGG.

Results

A total of 326 differentially-expressed genes (DEGs), were identified from 511 primary LGG tumor and 18 recurrent samples. Gene ontology (GO) analysis revealed that the DEGs were implicated in cell differentiation, neuron differentiation, negative regulation of neuron differentiation, and cell proliferation in the forebrain. The Kyoto Encyclopedia of Genes and Genomes (KEGG) database suggests that DEGs are associated with proteoglycans in cancer, the Wnt signaling pathway, ECM-receptor interaction, the PI3K-Akt signaling pathway, transcriptional deregulation in cancer, and the Hippo signaling pathway. The hub DEGs in the protein–protein interaction network are apolipoprotein A2 (APOA2), collagen type III alpha 1 chain (COL3A1), collagen type I alpha 1 chain (COL1A1), tyrosinase (TYR), collagen type I alpha 2 chain (COL1A2), neurotensin (NTS), collagen type V alpha 1 chain (COL5A1), poly(A) polymerase beta (PAPOLB), insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), and anomalous homeobox (ANHX). GSEA revealed that the following biological processes may associated with LGG recurrence: cell cycle, DNA replication and repair, regulation of apoptosis, neuronal differentiation, and Wnt signaling pathway.

Conclusions

Our study demonstrated that hub DEGs may assist in the molecular understanding of LGG recurrence. These findings still need further molecular studies to identify the assignment of DEGs in LGG.

Brain IGFBP-5 modifies the relation of depressive symptoms to decline in cognition in older persons

BACKGROUND

Brain proteins, including Insulin-like Growth Factor Binding Protein 5 (IGFBP-5), have been associated with cognitive dysfunction in aging. Mechanisms linking depression with cognition are poorly understood. We hypothesize that the association of depressive symptoms with cognition is mediated or modified by brain proteins.

METHODS

IGFBP-5, HSPB2, AK4, ITPK1 and PLXNB1 were measured in dorsolateral prefrontal cortex in 1057 deceased participants, who underwent annual assessments of depressive symptoms and cognition for a mean of 8.9 years. The average number of depressive symptoms per year before a dementia diagnosis was calculated for each person.

RESULTS

A one standard deviation above the mean IGFBP-5 was associated with a 14% higher odds of having more depressive symptoms (p < 0.031). Higher IGFBP-5 was associated with faster decline in global cognition (p < 0.001) and five cognitive domains (p < 0.008), controlling for depressive symptoms. IGFBP-5 moderated the association of depressive symptoms with decline in global cognition (p = 0.045). IGFBP-5 mediated ten percent or less of the total effect of depressive symptoms on decline in global cognition and the cognitive domains (p > 0.070).

LIMITATIONS

Participants were volunteers and self-selection bias limits the generalizability of our findings. In addition, we used self-reported data on depressive symptoms. However, we also used data on depression medications as sensitivity analyses to confirm findings.

CONCLUSIONS

In old age, brain IGFBP-5 is associated with depressive symptoms and cognition. The association of depressive symptoms with cognitive decline is conditional on IGFBP-5.

Synthetic Triterpenoid CDDO-Me Inhibits Proliferation, Migration, and Invasion in GBM8401 and GBM8901

Objectives:

We determined the anticancer potency of CDDO-Me in glioblastoma cell lines and the underlying mechanisms in vitro.

Summary:

CDDO-Me is a synthetic triterpenoid with more potent anticancer and cancer preventive actions compared with the original triterpenoid CDDO.

Methods:

Two glioblastoma cell lines, GBM8401 and GBM8901, were utilized to test the effect of CDDO-Me on cell viability, cell migration, and cell invasion using the MTT, wound healing, and transwell migration assays, respectively. Additionally, Western blotting was used to determine the protein expression levels of N-cadherin, cyclin D1, and vascular endothelial growth factor.

Results:

At nanomolar concentrations, CDDO-Me inhibited proliferation, migration, and invasion in both cell lines. In addition, CDDO-Me exhibited a dose-dependent downregulation in the protein levels of N-cadherin, cyclin D1, and vascular endothelial growth factor in GBM8401 and GBM8901 cells.

Conclusions:

CDDO-Me exhibited anticancer effects at low nanomolar concentrations and should be considered as a potential chemotherapeutic agent for glioblastoma.

Suppression of tumor growth via IGFBP3 depletion as a potential treatment in glioma

OBJECTIVE

Despite intensive medical treatment, patients with glioblastoma (grade IV glioma [GBM]) have a low 5-year survival rate of 5.5%. In this study, the authors tried to improve currently used therapies by identification of a therapeutic target, IGFBP3, for glioma treatment.

METHODS

IGFBP3 RNA expression in 135 patients newly diagnosed with glioma was correlated with clinicopathological factors. Immunohistochemical analysis was performed to determine IGFBP3 protein expression in glioma specimens. The effect of IGFBP3 depletion on cell proliferation was examined using IGFBP3 knockdown glioma cells. Intracranial infusion of IGFBP3 siRNAs was performed to evaluate the effect of IGFBP3 depletion in mouse intracranial xenograft models.

RESULTS

We demonstrated higher IGFBP3 expression in GBM than in tumor margin and grade II glioma. IGFBP3 expression was not only positively correlated with tumor grades but also associated with tumor histology and IDH1/2 mutation status. Additionally, higher IGFBP3 expression predicted shorter overall survival in glioma and GBM proneural subgroup patients. In vitro cell culture studies suggested IGFBP3 knockdown suppressed cell proliferation and induced cell cycle G2/M arrest as well as apoptosis in glioma cells. Also, accumulation of DNA double-strand breaks and γH2AX was observed in IGFBP3 knockdown cells. IGFBP3 knockdown delayed in vivo tumor growth in mouse subcutaneous xenograft models. Furthermore, convection-enhanced delivery of IGFBP3 siRNA to mouse brain suppressed intracranial tumor growth and prolonged survival of tumor-bearing mice.

CONCLUSIONS

Our findings suggest IGFBP3 predicts poor outcome of glioma patients and is a potential therapeutic target for which depletion of its expression suppresses tumor growth through inducing apoptosis and accumulation of DNA damage in glioma cells.

Effects of insulin-like growth factor binding protein 3 on apoptosis of cutaneous squamous cell carcinoma cells

Background

Cutaneous squamous cell carcinoma (CSCC) is the second most common carcinoma worldwide. Clinical treatment for patients with CSCC remains non-ideal. Insulin-like growth factor binding protein 3 (IGFBP3), a member of the insulin-like growth (IGF) system, participates in several biological processes, including cellular proliferation and apoptosis. Here, we explored the functional role of IGFBP3 in apoptosis and proliferation of A431 cells, a human CSCC cell line.

Materials and methods

Differential expression analysis, immunohistochemistry, immunoblotting, TUNEL assay, and CCK8 assay techniques were used to investigate the IGFBP3 expression levels in both A431 cells and CSCC tissue surgically obtained from humans as well as to explore the functional role of IGFBP3 in the apoptosis and proliferation of A431 cells.

Results

By using normal epidermal keratinocytes for comparison, we identified the top 10 ranked differentially upregulated genes expressed in human cutaneous squamous cell carcinoma cell lines. Among these 10 genes, IGFBP3 was ranked number 1. By using immunohistochemistry, we found that the expression level of IGFBP3 was significantly elevated in CSCC tissue compared with that in normal human skin tissue. Knockdown of IGFBP3 in A431 cells by transfection with IGFBP3-specific siRNA markedly altered the expression of proteins that contribute to apoptosis via mitochondrial pathways, significantly suppressing the expression of Bax and active caspase-3, while significantly increasing B-cell lymphoma-2 expression. TUNEL assay confirmed the effect of knockdown of IGFBP3 on the apoptosis as well. In addition, knockdown of IGFBP3 inhibited the proliferation of A431 cells.

Conclusion

IGFBP3 is overexpressed in both CSCC cell lines and tissue. Knockdown of IGFBP3 enhanced the apoptosis via a mitochondrial pathway and inhibited the proliferation of A431 cells. These findings indicate that IGFBP3 may be a biomarker and a potential therapeutic target for CSCC.

IGFBP6 controls the expansion of chemoresistant glioblastoma through paracrine IGF2/IGF-1R signaling

BACKGROUND

Glioblastomas (GBMs), the most common and most lethal of the primary brain tumors, are characterized by marked intra-tumor heterogeneity. Several studies have suggested that within these tumors a restricted population of chemoresistant glioma cells is responsible for recurrence. However, the gene expression patterns underlying chemoresistance are largely unknown. Numerous efforts have been made to block IGF-1R signaling pathway in GBM. However, those therapies have been repeatedly unsuccessful. This failure may not only be due to the complexity of IGF receptor signaling, but also due to complex cell-cell interactions in the tumor mass. We hypothesized that differential expression of proteins in the insulin-like growth factor (IGF) system underlie cell-specific differences in the resistance to temozolomide (TMZ) within GBM tumors.

METHODS

Expression of IGF-1R was analyzed in cell lines, patient-derived xenograft cell lines and human biopsies by cell surface proteomics, flow cytometry, immunofluorescence and quantitative real time polymerase chain reaction (qRT-PCR). Using gain-of-function and loss-of-function strategies, we dissected the molecular mechanism responsible for IGF-binding protein 6 (IGFBP6) tumor suppressor functions both in in vitro and in vivo. Site direct mutagenesis was used to study IGFBP6-IGF2 interactions.

RESULTS

We determined that in human glioma tissue, glioma cell lines, and patient-derived xenograft cell lines, treatment with TMZ enhances the expression of IGF1 receptor (IGF-1R) and IGF2 and decreases the expression of IGFBP6, which sequesters IGF2. Using chemoresistant and chemosensitive wild-type and transgenic glioma cells, we further found that a paracrine mechanism driven by IGFBP6 secreted from TMZ-sensitive cells abrogates the proliferation of IGF-1R-expressing TMZ-resistant cells in vitro and in vivo. In mice bearing intracranial human glioma xenografts, overexpression of IGFBP6 in TMZ-resistant cells increased survival. Finally, elevated expression of IGF-1R and IGF2 in gliomas associated with poor patient survival and tumor expression levels of IGFBP6 directly correlated with overall survival time in patients with GBM.

CONCLUSIONS

Our findings support the view that proliferation of chemoresistant tumor cells is controlled within the tumor mass by IGFBP6-producing tumor cells; however, TMZ treatment eliminates this population and enriches the TMZ-resistant cell populationleading to accelerated growth of the entire tumor mass.

Enhancement of mammary tumour growth by IGFBP-3 involves impaired T cell accumulation

Epidemiological studies show an association between obesity and poor breast cancer prognosis. We previously demonstrated that global IGFBP-3 deficiency, in IGFBP-3-null mice, resulted in a 50% reduction in mammary tumour growth over 3 weeks relative to tumours in wild-type (WT) C57BL/6 mice. This growth reduction was ameliorated by high fat feeding-induced obesity. This study aimed to examine how IGFBP-3 promotes tumour growth by influencing the immune tumour microenvironment in healthy and obese mice. Syngeneic EO771 cells, which lack detectable IGFBP-3 expression, were grown as orthotopic tumours in WT and IGFBP-3-null C57BL/6 mice placed on either a control chow or a high-fat diet (HFD), and examined by quantitative PCR and immunohistochemistry. In WT mice, increased stromal expression of IGFBP-3 was positively associated with tumour growth, supporting the hypothesis that IGFBP-3 in the microenvironment promotes tumour progression. Examining markers of immune cell subsets, gene expression of Ifng, Cd8a, Cd8b1 and Tnf and CD8 measured by immunohistochemistry were elevated in tumours of IGFBP-3-null mice compared to WT, indicating an accumulation of CD8+ T cells, but this increase was absent if the IGFBP-3-null mice had been exposed to HFD. Expression of these genes was negatively associated with tumour growth. Although similar among groups overall, Nkg2d and Tnfsf10 tumoural expression was associated with decreased tumour growth. Overall, the results of this study provide an immune-based mechanism by which host IGFBP-3 may promote breast tumour growth in the EO771 murine breast cancer model, and suggest that targeting IGFBP-3 might make a novel contribution to immune therapy for breast cancer.

Nuclear Insulin-Like Growth Factor Binding Protein-3 As a Biomarker in Triple-Negative Breast Cancer Xenograft Tumors: Effect of Targeted Therapy and Comparison With Chemotherapy

Triple-negative breast cancer (TNBC) typically has a worse outcome than other breast cancer subtypes, in part owing to a lack of approved therapeutic targets or prognostic markers. We have previously described an oncogenic pathway in basal-like TNBC cells, initiated by insulin-like growth factor binding protein-3 (IGFBP-3), in which the epidermal growth factor receptor (EGFR) is transactivated by sphingosine-1-phosphate (S1P) resulting from sphingosine kinase (SphK)-1 activation. Oncogenic IGFBP-3 signaling can be targeted by combination treatment with the S1P receptor modulator and SphK inhibitor, fingolimod, and the EGFR kinase inhibitor, gefitinib (F + G). However, the interaction of this treatment with chemotherapy has not been documented. Since we observed nuclear localization of IGFBP-3 in some TNBC tumors, this study aimed to evaluate the prognostic significance of nuclear IGFBP-3 in pre-clinical models of basal-like TNBC treated with F + G and doxorubicin. Orthotopic xenograft tumors were grown in nude mice from the human basal-like TNBC cell lines MDA-MB-468 and HCC1806, and were treated with gefitinib, 25 mg/Kg, plus fingolimod, 5 mg/Kg, 3-times weekly. In some studies, doxorubicin was also administered once weekly for 6 weeks. Tumor tissue proteins were quantitated by immunohistochemistry (IHC). Interaction between doxorubicin and F + G was also studied in proliferation assays in vitro. In both tumor models, tissue staining for IGFBP-3 was predominantly nuclear. Combination of F + G significantly enhanced mouse survival, decreased nuclear IGFBP-3 and Ki67 staining, and increased apoptosis (cleaved caspase-3) staining. Kaplan-Meier survival analysis showed that a high tumor IGFBP-3 IHC score (>median), like a high Ki67 score, was significantly associated with shorter survival time, whereas a high apoptosis score was associated with prolonged survival. Studied in vitro in both cell lines, low-dose doxorubicin that had little effect alone, strongly enhanced the cytostatic effect of low-dose F + G combination. However, in both in vivo models, doxorubicin at maximum-tolerated dose neither inhibited tumor growth when administered alone, nor enhanced the significant inhibitory effect of F + G. We conclude that doxorubicin may not add benefit to the inhibitory effect of F + G unless its dose-limiting toxicity can be overcome. Nuclear IGFBP-3 appears to have potential as a prognostic marker in TNBC and could be evaluated for clinical utility.

Human fibulin-3 protein variant expresses anti-cancer effects in the malignant glioma extracellular compartment in intracranial xenograft models

Background

Decades of cytotoxic and more recently immunotherapy treatments for malignant glioma have had limited success due to dynamic intra-tumoral heterogeneity. The dynamic interplay of cancer cell subpopulations has been found to be under the control of proteins in the cancer microenvironment. EGF-containing fibulin-like extracellular matrix protein (EFEMP1) (also fibulin-3) has the multiple functions of suppressing cancer growth and angiogenesis, while promoting cancer cell invasion. EFEMP1-derived tumor suppressor protein (ETSP) retains EFEMP1’s anti-growth and anti-angiogenic functions while actually inhibiting cancer cell invasion.

Methods

In this study, we examined the therapeutic effect on glioblastoma multiforme (GBM) of an in vitro synthesized protein, ZR30, which is based on the sequence of ETSP, excluding the signaling peptide.

Results

ZR30 showed the same effects as ETSP in blocking EGFR/NOTCH/AKT signaling pathways, when applied to cultures of multiple GBM cell lines and primary cultures. ZR30’s inhibition of MMP2 activation was shown not only for GBM cells, but also for other types of cancer cells having overexpression of MMP2. A significant improvement in survival of mice with orthotopic human GBM xenografts was observed after a single, intra-tumoral injection of ZR30. Using a model mimicking the intra-tumoral heterogeneity of GBM with cell subpopulations carrying different invasive and proliferative phenotypes, we demonstrated an equal and simultaneous tumor suppressive effect of ZR30 on both tumor cell subpopulations, with suppression of FOXM1 and activation of SEMA3B expressions in the xenografts.

Conclusion

Overall, the data support a complementary pleiotrophic therapeutic effect of ZR30 acting in the extracellular compartment of GBM.

Secondary Intracranial Tumors Following Radiotherapy for Pituitary Adenomas: A Systematic Review

Pituitary adenomas are often treated with radiotherapy for the management of tumor progression or recurrence. Despite the improvement in cure rates, patients treated by radiotherapy are at risk of development of secondary malignancies. We conducted a comprehensive literature review of the secondary intracranial tumors that occurred following radiotherapy to pituitary adenomas to obtain clinicopathological characteristics. The analysis included 48 neuroepithelial tumors, 37 meningiomas, and 52 sarcomas which were published between 1959–2017, although data is missing regarding overall survival and type of irradiation in a significant proportion of the reports. The average onset age for the pituitary adenoma was 37.2 ± 14.4 years and the average latency period before the diagnosis of the secondary tumor was 15.2 ± 8.7 years. Radiotherapy was administered in pituitary adenomas at an average dose of 52.0 ± 19.5 Gy. The distribution of pituitary adenomas according to their function was prolactinoma in 10 (7.2%) cases, acromegaly in 37 (27.0%) cases, Cushing disease in 4 (2.9%) cases, PRL+GH in 1 (0.7%) case, non-functioning adenoma in 57 (41.6%) cases. Irradiation technique delivered was lateral opposing field in 23 (16.7%) cases, 3 or 4 field technique in 27 (19.6%) cases, rotation technique in 10 (7.2%) cases, radio surgery in 6 (4.3%) cases. Most of the glioma or sarcoma had been generated after lateral opposing field or 3/4 field technique. Fibrosarcomas were predominant before 1979 (p < 0.0001). The median overall survival time for all neuroepithelial tumors was 11 months (95% confidence intervals (CI), 3–14). Patients with gliomas treated with radiotherapy exhibited a non-significant positive trend with longer overall survival. The median overall survival time for sarcoma cases was 6 months (95% CI, 1.5–9). The median survival time in patients with radiation and/or chemotherapy for sarcomas exhibited a non-significant positive trend with longer overall survival. In patients treated with radiotherapy for pituitary adenomas, the risk of secondary tumor incidence warrants a longer follow up period. Moreover, radiation and/or chemotherapy should be considered in cases of secondary glioma or sarcoma following radiotherapy to the pituitary adenomas.

Clinicopathological significance and impact on outcomes of the gene expression levels of IGF-1, IGF-2 and IGF-1R, IGFBP-3 in patients with colorectal cancer: Overexpression of the IGFBP-3 gene is an effective predictor of outcomes in patients with colorectal cancer

The insulin-like growth factors (IGF) system is involved in tumor proliferation, invasion and metastasis in cancer. The current study investigated the association of IGF-1, IGF-2 and IGF-1 receptor (IGF-1R), IGF binding proteins type 3 (IGFBP-3) mRNA expression levels with clinicopathological characteristics and outcomes of 202 patients with untreated colorectal cancer (CRC). IGF-1, IGF-2, IGF-1R and IGFBP-3 mRNA expression levels were analyzed in surgical specimens of cancer tissues and adjacent normal mucosa cells using reverse transcription-quantitative polymerase chain reaction. The IGF-1R gene expression level was significantly higher in cancer tissue compared with adjacent normal mucosa. By contrast, IGF-1 gene expression levels were reduced in cancer tissue compared with normal mucosa. IGF-2 and IGFBP-3 gene expression levels did not differ significantly between cancer tissue and adjacent normal mucosa. As for the association of gene expression and clinicopathological characteristics, IGFBP-3 gene expression was significantly associated with lymph node metastasis. High IGFBP-3 gene expression was associated with poor 5-year overall survival compared with patients with low IGFBP-3 expression. Furthermore, IGFBP-3 gene expression was identified as an independent prognostic factor using multivariate analysis. Overexpression of the IGFBP-3 gene is considered an effective independent predictor of outcomes in patients with CRC.

FBLN4 as candidate gene associated with long-term and short-term survival with primary glioblastoma

Background

Glioblastoma multiforme (GBM) is the most common malignant and lethal type of primary central nervous system tumor in humans. In spite of its high lethality, a small percentage of patients have a relatively good prognosis, with median survival times of 36 months or longer. The identification of clinical subsets of GBM associated with distinct molecular genetic profiles has made it possible to design therapies tailored to treat individual patients.

Methods

We compared microarray data sets from long-term survivors (LTSs) and short-term survivors (STSs) to screen for prognostic biomarkers in GBM patients using the WebArrayDB platform. We focused on FBLN4, IGFBP-2, and CHI3L1, all members of a group of 10 of the most promising, differentially regulated gene candidates. Using formalin-fixed paraffin-embedded GBM samples, we corroborated the relationship between these genes and patient outcomes using methylation-specific polymerase chain reaction (PCR) for MGMT methylation status and quantitative reverse transcription PCR for expression of these genes.

Results

Expression levels of the mRNAs of these 3 genes were higher in the GBM samples than in normal brain samples and these 3 genes were significantly upregulated in STSs compared to the levels in LTS samples (P<0.01). Furthermore, Kaplan–Meier analysis showed that the expression patterns of FBLN4 and IGFBP-2 serve as independent prognostic indicators for overall survival (P<0.01 and P<0.05, respectively).

Conclusion

To our knowledge, this is the first report describing FBLN4 as a prognostic factor for GBM patient survival, demonstrating that increased GBM survival time correlates with decreased FBLN4 expression. Understanding FBLN4 expression patterns could aid in the creation of powerful tools to predict clinical prognoses of GBM patients.

Spatial transcriptome analysis reveals Notch pathway-associated prognostic markers in IDH1 wild-type glioblastoma involving the subventricular zone

BACKGROUND

The spatial relationship of glioblastoma (GBM) to the subventricular zone (SVZ) is associated with inferior patient survival. However, the underlying molecular phenotype is largely unknown. We interrogated an SVZ-dependent transcriptome and potential location-specific prognostic markers.

METHODS

mRNA microarray data of a discovery set (n = 36 GBMs) were analyzed for SVZ-dependent gene expression and process networks using the MetaCore™ workflow. Differential gene expression was confirmed by qPCR in a validation set of 142 IDH1 wild-type GBMs that was also used for survival analysis.

RESULTS

Microarray analysis revealed a transcriptome distinctive of SVZ+ GBM that was enriched for genes associated with Notch signaling. No overlap was found to The Cancer Genome Atlas's molecular subtypes. Independent validation of SVZ-dependent expression confirmed four genes with simultaneous prognostic impact: overexpression of HES4 (p = 0.034; HR 1.55) and DLL3 (p = 0.017; HR 1.61) predicted inferior, and overexpression of NTRK2 (p = 0.049; HR 0.66) and PIR (p = 0.025; HR 0.62) superior overall survival (OS). Additionally, overexpression of DLL3 was predictive of shorter progression-free survival (PFS) (p = 0.043; HR 1.64). Multivariate analysis revealed overexpression of HES4 to be independently associated with inferior OS (p = 0.033; HR 2.03), and overexpression of DLL3 with inferior PFS (p = 0.046; HR 1.65).

CONCLUSIONS

We identified four genes with SVZ-dependent expression and prognostic significance, among those HES4 and DLL3 as part of Notch signaling, suggesting further evaluation of location-tailored targeted therapies.

Inhibition of 13-cis retinoic acid-induced gene expression of reactive-resistance genes by thalidomide in glioblastoma tumours in vivo

The cell differentiation potential of 13-cis retinoic acid (RA) has not succeeded in the clinical treatment of glioblastoma (GBM) so far. However, RA may also induce the expression of resistance genes such as HOXB7 which can be suppressed by Thalidomide (THAL). Therefore, we tested if combined treatment with RA+THAL may inhibit growth of glioblastoma in vivo. Treatment with RA+THAL but not RA or THAL alone significantly inhibited tumour growth. The synergistic effect of RA and THAL was corroborated by the effect on proliferation of glioblastoma cell lines in vitro. HOXB7 was not upregulated but microarray analysis validated by real-time PCR identified four potential resistance genes (IL-8, HILDPA, IGFBPA, and ANGPTL4) whose upregulation by RA was suppressed by THAL. Furthermore, genes coding for small nucleolar RNAs (snoRNA) were identified as a target for RA for the first time, and their upregulation was maintained after combined treatment. Pathway analysis showed upregulation of the Ribosome pathway and downregulation of pathways associated with proliferation and inflammation. In conclusion, combined treatment with RA + THAL delayed growth of GBM xenografts and suppressed putative resistance genes associated with hypoxia and angiogenesis. This encourages further pre-clinical and clinical studies of this drug combination in GBM.

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.

Insulin-like growth factor binding protein-2 regulates β-catenin signaling pathway in glioma cells and contributes to poor patient prognosis

BACKGROUND

Upregulation of insulin-like growth factor binding protein 2 (IGFBP-2) is often associated with aggressiveness of glioblastoma (GBM) and contributes to poor prognosis for GBM patients. In view of the regulation of β-catenin by IGFBP-2 in breast cancer and the crucial role of β-catenin pathway in glioma invasion, proliferation and maintenance of glioma stem cells, the mechanism of regulation of β-catenin by IGFBP-2, and its role in GBM prognosis was studied.

METHODS

Regulation of the β-catenin pathway was studied by immunocytochemistry, Western blot analysis, luciferase assays, and real-time RT-PCR. The role of IGFBP-2 was studied by subcutaneous tumor xenografts in immunocompromised mice using glioma cells engineered to express IGFBP-2 and its domains. GBM patient tumor tissues (n = 112) were analyzed for expression of IGFBP-2 and β-catenin by immunohistochemistry. Survival analysis was performed employing Cox regression and Kaplan-Meier survival analyses.

RESULTS

IGFBP-2 knockdown in U251, T98G, and U373 or overexpression in LN229 and U87 cells revealed a role for IGFBP-2 in stabilization of β-catenin and regulation of its nuclear functions involving integrin-mediated inactivation of GSK3β. Similar results were obtained upon overexpression of the C-terminal domain of IGFBP-2 but not the N-terminal domain. Subcutaneous xenograft tumors overexpressing either full-length or the C-terminal domain of IGFBP-2 showed larger volume as compared with controls. Coexpression of high levels of IGFBP-2 and β-catenin was associated with worse prognosis (P = .001) in GBM patients.

CONCLUSION

IGFBP-2 potentiates GBM tumor growth by the activation of the β-catenin pathway through its C-terminal domain, and their coexpression possibly contributes to worse patient prognosis.

Glioblastoma-derived Macrophage Colony-stimulating Factor (MCSF) Induces Microglial Release of Insulin-like Growth Factor-binding Protein 1 (IGFBP1) to Promote Angiogenesis

Glioblastoma (grade IV glioma/GBM) is the most common primary adult malignant brain tumor with poor prognosis. To characterize molecular determinants of tumor-stroma interaction in GBM, we profiled 48 serum cytokines and identified macrophage colony-stimulating factor (MCSF) as one of the elevated cytokines in sera from GBM patients. Both MCSF transcript and protein were up-regulated in GBM tissue samples through a spleen tyrosine kinase (SYK)-dependent activation of the PI3K-NFκB pathway. Ectopic overexpression and silencing experiments revealed that glioma-secreted MCSF has no role in autocrine functions and M2 polarization of macrophages. In contrast, silencing expression of MCSF in glioma cells prevented tube formation of human umbilical vein endothelial cells elicited by the supernatant from monocytes/microglial cells treated with conditioned medium from glioma cells. Quantitative proteomics based on stable isotope labeling by amino acids in cell culture showed that glioma-derived MCSF induces changes in microglial secretome and identified insulin-like growth factor-binding protein 1 (IGFBP1) as one of the MCSF-regulated proteins secreted by microglia. Silencing IGFBP1 expression in microglial cells or its neutralization by an antibody reduced the ability of supernatants derived from microglial cells treated with glioma cell-conditioned medium to induce angiogenesis. In conclusion, this study shows up-regulation of MCSF in GBM via a SYK-PI3K-NFκB-dependent mechanism and identifies IGFBP1 released by microglial cells as a novel mediator of MCSF-induced angiogenesis, of potential interest for developing targeted therapy to prevent GBM progression.

Definition of a serum marker panel for glioblastoma discrimination and identification of Interleukin 1β in the microglial secretome as a novel mediator of endothelial cell survival induced by C-reactive protein

Glioblastoma (GBM) is the most common malignant adult primary brain tumor. We profiled 724 cancer-associated proteins in sera of healthy individuals (n=27) and GBM (n=28) using antibody microarray. While 69 proteins exhibited differential abundance in GBM sera, a three-marker panel (LYAM1, BHE40 and CRP) could discriminate GBM sera from that of healthy donors with an accuracy of 89.7% and p<0.0001. The high abundance of C-reactive protein (CRP) in GBM sera was confirmed in 264 independent samples. High levels of CRP protein was seen in GBM but without a change in transcript levels suggesting a non-tumoral origin. Glioma-secreted Interleukin 6 (IL6) was found to induce hepatocytes to secrete CRP, involving JAK-STAT pathway. The culture supernatant from CRP-treated microglial cells induced endothelial cell survival under nutrient-deprivation condition involving CRP-FcγRIII signaling cascade. Transcript profiling of CRP-treated microglial cells identified Interleukin 1β (IL1β) present in the microglial secretome as the key mediator of CRP-induced endothelial cell survival. IL1β neutralization by antibody-binding or siRNA-mediated silencing in microglial cells reduced the ability of the supernatant from CRP-treated microglial cells to induce endothelial cell survival. Thus our study identifies a serum based three-marker panel for GBM diagnosis and provides leads for developing targeted therapies. Biological significance A complex antibody microarray based serum marker profiling identified a three-marker panel - LYAM1, BHE40 and CRP as an accurate discriminator of glioblastoma sera from that of healthy individuals. CRP protein is seen in high levels without a concomitant increase of CRP transcripts in glioblastoma. Glioma-secreted IL6 induced hepatocytes to produce CRP in a JAK-STAT signaling dependent manner. CRP induced microglial cells to release IL1β which in turn promoted endothelial cell survival. This study, besides defining a serum panel for glioblastoma discrimination, identified IL1β as a potential candidate for developing targeted therapy.

Understanding the Key to Targeting the IGF Axis in Cancer: A Biomarker Assessment

Type 1 insulin like growth factor receptor (IGF-1R) targeted therapies showed compelling pre-clinical evidence; however, to date, this has failed to translate into patient benefit in Phase 2/3 trials in unselected patients. This was further complicated by the toxicity, including hyperglycemia, which largely results from the overlap between IGF and insulin signaling systems and associated feedback mechanisms. This has halted the clinical development of inhibitors targeting IGF signaling, which has limited the availability of biopsy samples for correlative studies to understand biomarkers of response. Indeed, a major factor contributing to lack of clinical benefit of IGF targeting agents has been difficulty in identifying patients with tumors driven by IGF signaling due to the lack of predictive biomarkers. In this review, we will describe the IGF system, rationale for targeting IGF signaling, the potential liabilities of targeting strategies, and potential biomarkers that may improve success.

The Role of miR-21 in Cancer

MicroRNAs (miRNAs) are small endogenous noncoding RNAs that suppress gene expression at the post-transcriptional level. In the past decade, miRNAs have been extensively studied in a number of different human cancers. MiRNAs have been identified to act both as oncogenes and as tumor suppressors. In addition, miRNAs are associated with the intrinsic resistance of cancer to various forms of therapy, and they are implicated in both tumor progression and metastasis. The characterization of the specific alterations in the patterns of miRNA expression in cancer has great potential for identifying biomarkers for early cancer detection, as well as for potential therapeutic intervention in cancer treatment. In this chapter, we describe the ever-expanding role of miR-21 and its target genes in different cancers, and provide insight into how this oncogenic miRNA regulates cancer cell proliferation, migration, and apoptosis by suppressing the expression of tumor suppressors.

Novel anti IGFBP2 single chain variable fragment inhibits glioma cell migration and invasion

Insulin like growth factor binding protein 2 (IGFBP2) is highly up regulated in glioblastoma (GBM) tissues and has been one of the prognostic indicators. There are compelling evidences suggesting important roles for IGFBP2 in glioma cell proliferation, migration and invasion. Extracellular IGFBP2 through its carboxy terminal arginine glycine aspartate (RGD) motif can bind to cell surface α5β1 integrins and activate pathways downstream to integrin signaling. This IGFBP2 activated integrin signaling is known to play a crucial role in IGFBP2 mediated invasion of glioma cells. Hence a molecular inhibitor of carboxy terminal domain of IGFBP2 which can inhibit IGFBP2-cell surface interaction is of great therapeutic importance. In an attempt to develop molecular inhibitors of IGFBP2, we screened single chain variable fragment (scFv) phage display libraries, Tomlinson I (Library size 1.47 × 10(8)) and Tomlinson J (Library size 1.37 × 10(8)) using human recombinant IGFBP2. After screening we obtained three IGFBP2 specific binders out of which one scFv B7J showed better binding to IGFBP2 at its carboxy terminal domain, blocked IGFBP2-cell surface association, reduced activity of matrix metalloprotease 2 in the conditioned medium of glioma cells and inhibited IGFBP2 induced migration and invasion of glioma cells. We demonstrate for the first time that in vitro inhibition of extracellular IGFBP2 activity by using human scFv results in significant reduction of glioma cell migration and invasion. Therefore, the inhibition of IGFBP2 can serve as a potential therapeutic strategy in the management of GBM.

IGF-Binding Protein 2 - Oncogene or Tumor Suppressor?

The role of insulin-like growth factor binding protein 2 (IGFBP2) in cancer is unclear. In general, IGFBP2 is considered to be oncogenic and its expression is often observed to be elevated in cancer. However, there are a number of conflicting reports in vitro and in vivo where IGFBP2 acts in a tumor suppressor manner. In this mini-review, we discuss the factors influencing the variation in IGFBP2 expression in cancer and our interpretation of these findings.

Senescence-associated-gene signature identifies genes linked to age, prognosis, and progression of human gliomas

BACKGROUND

Senescence-associated genes (SAGs) are responsible for the senescence-associated secretory phenotype, linked in turn to cellular aging, the aging brain, and the pathogenesis of cancer.

OBJECTIVE

We hypothesized that senescence-associated genes are overexpressed in older patients, in higher grades of glioma, and portend a poor prognosis.

METHODS

Forty-seven gliomas were arrayed on a custom version of the Affymetrix HG-U133+2.0 GeneChip, for expression of fourteen senescence-associated genes: CCL2, CCL7, CDKN1A, COPG, CSF2RB, CXCL1, ICAM-1, IGFBP-3, IL-6, IL-8, SAA4, TNFRSF-11B, TNFSF-11 and TP53. A combined "senescence score" was generated using principal component analysis to measure the combined effect of the senescence-associated gene signature.

RESULTS

An elevated senescence score correlated with older age (r=0.37; P=.01) as well as a higher degree of malignancy, as determined by WHO, histological grade (r=0.49; P<.001). There was a mild association with poor prognosis (P=.06). Gliosarcomas showed the highest scores. Six genes independently correlated with either age (IL-6, TNFRSF-11B, IGFBP-3, SAA4, and COPG), prognosis (IL-6, SAA4), or the grade of the glioma (IL-6, IL-8, ICAM-1, IGFBP-3, and COPG).

CONCLUSION

We report: 1) a novel molecular signature in human gliomas, based on cellular senescence, translating the concept of SAG to human cancer; 2) the senescence signature is composed of genes central to the pathogenesis of gliomas, defining a novel, aggressive subtype of glioma; and 3) these genes provide prognostic biomarkers, as well as targets, for drug discovery and immunotherapy.

MicroRNA-21 promotes glioblastoma tumorigenesis by down-regulating insulin-like growth factor-binding protein-3 (IGFBP3)

Despite advances in surgery, imaging, chemotherapy, and radiation, patients with glioblastoma multiforme (GBM), the most common histological subtype of glioma, have an especially dismal prognosis; >70% of GBM patients die within 2 years of diagnosis. In many human cancers, the microRNA miR-21 is overexpressed, and accumulating evidence indicates that it functions as an oncogene. Here, we report that miR-21 is overexpressed in human GBM cell lines and tumor tissue. Moreover, miR-21 expression in GBM patient samples is inversely correlated with patient survival. Knockdown of miR-21 in GBM cells inhibited cell proliferation in vitro and markedly inhibited tumor formation in vivo. A number of known miR-21 targets have been identified previously. By microarray analysis, we identified and validated insulin-like growth factor (IGF)-binding protein-3 (IGFBP3) as a novel miR-21 target gene. Overexpression of IGFBP3 in glioma cells inhibited cell proliferation in vitro and inhibited tumor formation of glioma xenografts in vivo. The critical role that IGFBP3 plays in miR-21-mediated actions was demonstrated by a rescue experiment, in which IGFBP3 knockdown in miR-21KD glioblastoma cells restored tumorigenesis. Examination of tumors from GBM patients showed that there was an inverse relationship between IGFBP3 and miR-21 expression and that increased IGFBP3 expression correlated with better patient survival. Our results identify IGFBP3 as a novel miR-21 target gene in glioblastoma and suggest that the oncogenic miRNA miR-21 down-regulates the expression of IGFBP3, which acts as a tumor suppressor in human glioblastoma.

Comprehensive characterization of glioblastoma tumor tissues for biomarker identification using mass spectrometry-based label-free quantitative proteomics

Cancer is a complex disease; glioblastoma (GBM) is no exception. Short survival, poor prognosis, and very limited treatment options make it imperative to unravel the disease pathophysiology. The critically important identification of proteins that mediate various cellular events during disease is made possible with advancements in mass spectrometry (MS)-based proteomics. The objective of our study is to identify and characterize proteins that are differentially expressed in GBM to better understand their interactions and functions that lead to the disease condition. Further identification of upstream regulators will provide new potential therapeutic targets. We analyzed GBM tumors by SDS-PAGE fractionation with internal DNA markers followed by liquid chromatography-tandem mass spectrometry (MS). Brain tissue specimens obtained for clinical purposes during epilepsy surgeries were used as controls, and the quantification of MS data was performed by label-free spectral counting. The differentially expressed proteins were further characterized by Ingenuity Pathway Analysis (IPA) to identify protein interactions, functions, and upstream regulators. Our study identified several important proteins that are involved in GBM progression. The IPA revealed glioma activation with z score 2.236 during unbiased core analysis. Upstream regulators STAT3 and SP1 were activated and CTNNα was inhibited. We verified overexpression of several proteins by immunoblot to complement the MS data. This work represents an important step towards the identification of GBM biomarkers, which could open avenues to identify therapeutic targets for better treatment of GBM patients. The workflow developed represents a powerful and efficient method to identify biomarkers in GBM.

STAT-1 expression is regulated by IGFBP-3 in malignant glioma cells and is a strong predictor of poor survival in patients with glioblastoma

OBJECT

Insulin-like growth factor binding proteins (IGFBPs) have been implicated in the pathogenesis of glioma. In a previous study the authors demonstrated that IGFBP-3 is a novel glioblastoma biomarker associated with poor survival. Since signal transducer and activator of transcription 1 (STAT-1) has been shown to be regulated by IGFBP-3 during chondrogenesis and is a prosurvival and radioresistant molecule in different tumors, the aim in the present study was to explore the functional significance of IGFBP-3 in malignant glioma cells, to determine if STAT-1 is indeed regulated by IGFBP-3, and to study the potential of STAT-1 as a biomarker in glioblastoma.

METHODS

The functional significance of IGFBP-3 was investigated using the short hairpin (sh)RNA gene knockdown approach on U251MG cells. STAT-1 regulation by IGFBP-3 was tested on U251MG and U87MG cells by shRNA gene knockdown and exogenous treatment with recombinant IGFBP-3 protein. Subsequently, the expression of STAT-1 was analyzed with real-time reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) in glioblastoma and control brain tissues. Survival analyses were done on a uniformly treated prospective cohort of adults with newly diagnosed glioblastoma (136 patients) using Kaplan-Meier and Cox regression models.

RESULTS

IGFBP-3 knockdown significantly impaired proliferation, motility, migration, and invasive capacity of U251MG cells in vitro (p < 0.005). Exogenous overexpression of IGFBP-3 in U251MG and U87MG cells demonstrated STAT-1 regulation. The mean transcript levels (by real-time RT-PCR) and the mean labeling index of STAT-1 (by IHC) were significantly higher in glioblastoma than in control brain tissues (p = 0.0239 and p < 0.001, respectively). Multivariate survival analysis revealed that STAT-1 protein expression (HR 1.015, p = 0.033, 95% CI 1.001-1.029) along with patient age (HR 1.025, p = 0.005, 95% CI 1.008-1.042) were significant predictors of shorter survival in patients with glioblastoma.

CONCLUSIONS

IGFBP-3 influences tumor cell proliferation, migration, and invasion and regulates STAT-1 expression in malignant glioma cells. STAT-1 is overexpressed in human glioblastoma tissues and emerges as a novel prognostic biomarker.

Correlation of altered expression of the autophagy marker LC3B with poor prognosis in astrocytoma

Glioblastoma multiforme is one of the most serious malignant brain tumors and is characterized by resistance to chemotherapy and radiation therapy. Recent studies suggest that autophagy may play an important role not only in the regulation of cancer development and progression but also in determining the response of cancer cells to anticancer therapy. The purpose of the present study was to assess the relationship between protein expressions of two autophagy markers, LC3B and Beclin-1, with clinical parameters in astrocytoma patients. Furthermore, the expression of CD133, a marker of the cancer stem-like cells, in astrocytoma patients was also investigated. A total of 106 thin-section slides were retrospectively collected from astrocytoma patients. LC3B, but not Beclin-1, protein expression was found to significantly correlate with resistance to radiation- or chemotherapy. In addition, high intensity of LC3B staining was predictive of poor prognosis. Furthermore, survival time of patients with high-level expression in both CD133 and LC3B was significantly shorter than those with weak expression in both CD133 and LC3B. These results suggest that astrocytoma cancer stem-like cells together with enhanced autophagy may cause resistance to radiation therapy/chemotherapy and that targeting the cancer stem-like cell in astrocytoma may offer a viable therapeutic approach.

Plasma IGFBP-2 levels after postoperative combined radiotherapy and chemotherapy predict prognosis in elderly glioblastoma patients

It has been found that preoperative plasma IGFBP-2 levels correlate with prognosis in glioma patients. The prognostic value of plasma IGFBP-2 after postoperative combined radiotherapy and chemotherapy in glioma patients is unknown. Plasma IGFBP-2 levels in 83 glioblastoma patients after postoperative radiotherapy plus chemotherapy were analyzed using an IGFBP-2 ELISA kit. We found that after standard therapy plasma IGFBP-2 levels significantly correlated with the patient's age (R = 0.738, P<0.001) and Karnofsky performance status (KPS, R = −0.633, P<0.05). Cox proportional hazards models were used to calculate hazard ratios (HRs) of death according to plasma IGFBP-2 levels adjusted for patient clinical characteristics. Plasma IGFBP-2 levels significantly correlated with overall survival in glioblastoma patients (multivariate HR = 1.035; 95% CI, 1.024–1.047; P<0.001). The effect of plasma IGFBP-2 levels on survival seemed to differ according to patients' age. Among patients older than 60, high plasma IGFBP-2 levels were associated with a significant increase in overall mortality (HR = 1.097; 95% CI, 1.055–1.140; P<0.001). In contrast, plasma IGFBP-2 levels conferred no significant effect on mortality among patients younger than 60. Elevated plasma IGFBP-2 levels after combined postoperative radiotherapy and chemotherapy in elderly glioblastoma patients correlate with poor KPS score and predicts poor prognosis.

Antioxidants delay clinical signs and systemic effects of ENU induced brain tumors in rats

According to our previous study suggesting that antioxidant properties of phytochemicals in the diet decrease glioma aggressiveness, we used a SUVIMAX-like diet ("Supplementation en VItamines et Minéraux AntioXydants") (enriched with alpha-tocopherol, beta carotene, vitamin C, zinc, and sodium selenite), adapted to rats. The present results showed that each of the antioxidants inhibited growth of glioma cells in vitro. When used in combination for in vivo studies, we showed a highly significant delay in the clinical signs of the disease, but not a statistical significant difference in the incidence of glioma in an Ethyl-nitrosourea (ENU)-model. The SUVIMAX-like diet decreased candidate markers of tumoral aggressiveness and gliomagenesis progression. The mRNA expressions of 2 common markers in human glioma: Mn-SOD (Manganese Superoxide Dismutase) and IGFBP5 (insulin growth factor binding protein) were reduced in the tumors of rats fed the antioxidant diet. In addition, the transcripts of two markers linked to brain tumor proliferation, PDGFRb (platelet-derived growth factor receptor beta) and Ki-67, were also significantly decreased. On the whole, our results suggest a protective role for antioxidants to limit aggressiveness and to some extent, progression of gliomas, in a rat model.