Pathology: Commonly Monitored Glioblastoma Markers: EFGR, EGFRvIII, PTEN, and MGMT

Modulation of Genes and MicroRNAs in the Neurospheres of Glioblastoma Cell Lines U343 and T98G Induced by Ionizing Radiation and Temozolomide Therapy

INTRODUCTION

Glioblastoma is the most prevalent primary malignant neoplasm of the central nervous system. It has increased its incidence, while the overall survival remains over 14 months.

PURPOSE

The purpose is to evaluate the expression of the genes EGFR, PTEN, MGMT, and IDH1/2, and microRNAs miR-181b, miR-145, miR-149, and miR-128a in adhered cells (AC) and neurospheres (NS) from cell lines (T98G and U343) submitted to temozolomide (TMZ) and ionizing radiation (IR).

METHODS

T98G and U343 were treated with TMZ, IR, and TMZ+IR. The analysis of gene expression and miRNAs was performed using real-time PCR.

RESULTS

This study demonstrated: a) an improvement in the expression of IDH1 after IR and TMZ + IR in the NS (T98G); b) an increase in the expression of MGMT in NS (T98G) in IR groups and TMZ + IR. The expression of miRNAs results as a) AC (U343) expressed more miR-181b after TMZ, IR, and TMZ + IR; and miR-128a improved after TMZ, IR, and TMZ + IR; b) NS (T98G) after TMZ + IR expressed: miR-181b; miR-149; miR-145 and miR-128a; c) NS (U343) after IR huge expressed miR-149 and miR-145.

CONCLUSION

IR was an independent and determining radioresistance factor in NS. However, we observed no complementarity action of oncomiRs regulation.

Prognostic Impact of Low-Level p53 Expression on Brain Astrocytomas Immunopositive for Epidermal Growth Factor Receptor

Although the expression of p53 and epidermal growth factor receptor (EGFR) is associated with therapeutic resistance and patient outcomes in many malignancies, the relationship in astrocytomas is unclear. This study aims to correlate p53 and EGFR expression in brain astrocytomas with overall patient survival. Eighty-two patients with astrocytomas were enrolled in the study. Semi-quantitative p53 and EGFR immunohistochemical staining was measured in tumor specimens. The mean follow-up after astrocytoma surgery was 18.46 months. The overall survival rate was 83%. Survival was reduced in EGFR-positive patients compared with survival in EGFR-negative patients (p < 0.05). However, no significant differences in survival were detected between patients with high and low p53 expression. In patients with low p53 expression, positive EGFR staining was associated with significantly worse survival compared with patients with negative EGFR staining (log-rank test: p < 0.001). Survival rates in positive and negative EGFR groups with high p53 protein expression were similar (log-rank test: p = 0.919). The IC50 of an EGFR inhibitor was higher in GBM cells with high p53 protein expression compared with the IC50 in cells with low p53 expression. Combined EGFR and p53 expression may have prognostic significance in astrocytomas.

EGFRvIII peptide nanocapsules and bevacizumab nanocapsules: a nose-to-brain multitarget approach against glioblastoma

Aim: To evaluate the antitumor efficacy of bevacizumab-functionalized nanocapsules in a rat glioblastoma model after the pretreatment with nanocapsules functionalized with a peptide-specific to the epidermal growth factor receptor variant III. Materials & methods: Nanocapsules were prepared, physicochemical characterized and intranasally administered to rats. Parameters such as tumor size, histopathological characteristics and infiltration of CD8⁺ T lymphocytes were evaluated. Results: The strategy of treatment resulted in a reduction of 87% in the tumor size compared with the control group and a higher infiltration of CD8⁺ T lymphocytes in tumoral tissue. Conclusion: The block of two different molecular targets using nose-to-brain delivery represents a new and promising approach against glioblastoma.

Monocarboxylate Transporter 4 Regulates Glioblastoma Motility and Monocyte Binding Ability

Glioblastoma (GBM) is characterized by severe hypoxic and acidic stress in an abnormal microenvironment. Monocarboxylate transporter (MCT)4, a pH-regulating protein, plays an important role in pH homeostasis of the glycolytic metabolic pathways in cancer cells. The present study showed that GBM exposure to hypoxic conditions increased MCT4 expression. We further analyzed the glioma patient database and found that MCT4 was significantly overexpressed in patients with GBM, and the MCT4 levels positively correlated with the clinico-pathological grades of gliomas. We further found that MCT4 knockdown abolished the hypoxia-enhanced of GBM cell motility and monocyte adhesion. However, the overexpression of MCT4 promoted GBM cell migration and monocyte adhesion activity. Our results also revealed that MCT4-regulated GBM cell motility and monocyte adhesion are mediated by activation of the serine/threonine-specific protein kinase (AKT), focal adhesion kinase (FAK), and epidermal growth factor receptor (EGFR) signaling pathways. Moreover, hypoxia mediated the acetylated signal transducer and activator of transcription (STAT)3 expression and regulated the transcriptional activity of hypoxia inducible factor (HIF)-1α in GBM cell lines. In a GBM mouse model, MCT4 was significantly increased in the tumor necrotic tissues. These findings raise the possibility for the development of novel therapeutic strategies targeting MCT4.

Mucin O-glycosylating enzyme GALNT2 facilitates the malignant character of glioma by activating the EGFR/PI3K/Akt/mTOR axis

N-Acetylgalactosaminyltransferase 2 (GALNT2), the enzyme that regulates the initial step of mucin O-glycosylation, has been reported to play a role in influencing the malignancy of various cancers. However, the mechanism through which it influences gliomas is still unknown. In the current study, the Cox proportional hazards model was used to select genes. Data obtained from The Cancer Genome Atlas (TCGA) database and immunohistochemistry (IHC) of clinical specimens showed that increased GALNT2 expression levels were associated with an unfavorable prognosis and a higher tumor grade in human gliomas. Then, GALNT2 knockdown and overexpression were performed in glioma cell lines and verified by quantitative real-time PCR (qRT-PCR) and Western blotting. Functional assays demonstrated that GALNT2 was closely related to glioma cell proliferation, cycle transition, migration and invasion. Western blot analysis and lectin pull-down assays indicated that GALNT2 knockdown decreased the level of phosphorylated epidermal growth factor receptor (EGFR) and the expression of the Tn antigen on EGFR and affected the expression levels of p21, cyclin-dependent kinase 4 (CDK4), cyclinD1, matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 9 (MMP9) through the EGFR/PI3K/Akt/mTOR pathway. GALNT2 overexpression had the opposite effects. In vivo, the growth of orthotopic glioma xenografts in nude mice was distinctly inhibited by the expression of GALNT2 shRNA, and the tumors with GALNT2 shRNA exhibited less aggressiveness and reduced expression of Ki67 and MMP2. Overall, GALNT2 facilitates the malignant characteristics of glioma by influencing the O-glycosylation and phosphorylation of EGFR and the subsequent downstream PI3K/Akt/mTOR axis. Therefore, GALNT2 may serve as a novel biomarker and a potential target for future therapy of glioma.

PRL-3 is a potential glioblastoma prognostic marker and promotes glioblastoma progression by enhancing MMP7 through the ERK and JNK pathways

Purpose: Glioblastoma is the most common and aggressive type of primary brain malignancy and is associated with a poor prognosis. Previously, we found that phosphatase of regenerating liver-3 (PRL-3) was significantly up-regulated in glioblastoma as determined by a microarray analysis. However, the function of PRL-3 in glioblastoma remains unknown. We aimed to investigate the clinical relationship between PRL-3 and glioblastoma, and uncover the mechanisms of PRL-3 in the process of glioblastoma.

Methods: PRL-3 expression was evaluated in 61 glioblastoma samples and 4 cell lines by RT-qPCR and immunohistochemistry. Kaplan-Meier analysis was performed to evaluate the prognostic value of PRL-3 for overall survival (OS) and progression-free survival (PFS) for glioblastoma patients. Proliferation was evaluated by Cell Counting Kit-8 (CCK-8) assay and EdU proliferation assay, migration and invasion by wound-closure/Transwell assays, and qRT-PCR/immunoblotting/IHC were used for both in vivo and in vitro investigations.

Result: A high PRL-3 expression level was closely correlated with unfavorable OS and PFS for glioblastoma patients, and was also significantly correlated with Ki-67 expression. Down-regulation of PRL-3 inhibited glioma cell proliferation, invasion and migration through ERK/JNK/matrix metalloproteinase 7 (MMP7) in vitro and in vivo.

Conclusions: PRL-3 expression enhances the invasion and proliferation of glioma cells, highlighting this phosphatase as a novel prognostic candidate and an attractive target for future therapy in glioblastoma.

Immune Evasion Strategies of Glioblastoma

Glioblastoma (GBM) is the most devastating brain tumor, with associated poor prognosis. Despite advances in surgery and chemoradiation, the survival of afflicted patients has not improved significantly in the past three decades. Immunotherapy has been heralded as a promising approach in treatment of various cancers; however, the immune privileged environment of the brain usually curbs the optimal expected response in central nervous system malignancies. In addition, GBM cells create an immunosuppressive microenvironment and employ various methods to escape immune surveillance. The purpose of this review is to highlight the strategies by which GBM cells evade the host immune system. Further understanding of these strategies and the biology of this tumor will pave the way for developing novel immunotherapeutic approaches for treatment of GBM.

Glioblastoma antigen discovery--foundations for immunotherapy

Prognosis for patients with glioblastoma (GBM), the most common high-grade primary central nervous system (CNS) tumor, remains discouraging despite multiple discoveries and clinical advances. Immunotherapy has emerged as a promising approach to GBM therapy as the idea the human CNS is immunoprivileged is being challenged. Early clinical studies of vaccine-based approaches have been encouraging, but further investigation is required before these therapies become clinically meaningful. A key challenge in immunotherapy involves identification of target antigens that are specific and sensitive for GBM. Here we discuss tumor-associated antigens that have been targeted for GBM therapy, strategies for discovery of novel antigens, and the theory of epitope spreading as it applies to GBM immunotherapy.

Combining immunotherapy with radiation for the treatment of glioblastoma

Glioblastoma is a devastating cancer with universally poor outcomes in spite of current standard multimodal therapy. Immunotherapy is an attractive new treatment modality given its potential for exquisite specificity and its favorable side effect profile; however, clinical trials of immunotherapy in GBM have thus far shown modest benefit. Optimally combining radiation with immunotherapy may be the key to unlocking the potential of both therapies given the evidence that radiation can enhance anti-tumor immunity. Here we review this evidence and discuss considerations for combined therapy.

Glioma diagnostics and biomarkers: an ongoing challenge in the field of medicine and science

Glioma is the most common brain tumor. For the more aggressive form, glioblastoma, standard treatment includes surgical resection, irradiation with adjuvant temozolomide and, on recurrence, experimental chemotherapy. However, the survival of patients remains poor. There is a critical need for minimally invasive biomarkers for diagnosis and as measures of response to therapeutic interventions. Glioma shed extracellular vesicles (EVs), which invade the surrounding tissue and circulate within both the cerebrospinal fluid and the systemic circulation. These tumor-derived EVs and their content serve as an attractive source of biomarkers. In this review, we discuss the current state of the art of biomarkers for glioma with emphasis on their EV derivation.

Aromatase and estrogen receptor alpha mRNA expression as prognostic biomarkers in patients with astrocytomas

Estrogens are oncogenic hormones at a high level in breast, prostate, endometrial and lung cancer. Estrogens are synthesized by aromatase which has been used as a biomarker both in breast and lung cancer. Estrogen biological activities are executed by their classic receptors (ERα and ERβ). ERα has been described as a cancer promoter and ERβ, as a possible tumor suppressor. Both receptors are present at low levels in primary multiforme glioblastoma (GBM). The GBM frequency is 50 % higher in men than in women. The GBM patient survival period ranges from 7 to 18 months. The purpose of this pilot study was to evaluate aromatase and estrogen receptor expression, as well as 17ß-estradiol concentration in astrocytoma patients biopsies to obtain a prognosis biomarker for these patients. We analyzed 36 biopsies of astrocytoma patients with a different grade (I-IV) of malignity. Aromatase and estrogen receptor mRNA expression were analyzed by semiquantitative RT-PCR, and the E2 levels, by ELISA. E2 concentration was higher in GBM, compared to grade II or III astrocytomas. The number of cells immunoreactive to aromatase and estrogen receptors decreased as the grade of tumor malignity increased. Aromatase mRNA expression was present in all biopsies, regardless of malignity grade or patient age or gender. The highest expression of aromatase mRNA in GBM patients was associated to the worst survival prognostic (6.28 months). In contrast lowest expression of ERα mRNA in astrocytoma patients had a worst prognosis. In conclusion, aromatase and ERα expression could be used as prognosis biomarkers for astrocytoma patients.

Combined PTEN Mutation and Protein Expression Associate with Overall and Disease-Free Survival of Glioblastoma Patients

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a tumor suppressor commonly inactivated in glioblastoma multiforme (GBM), but the prognostic significance of PTEN remains controversial. Here, we demon- strate significant prognostic value of combined PTEN mutation and expression for the survival of patients with GBM on the basis of analysis of large-scale cancer genomic data. PTEN nonsense mutations associated with sig- nificantly shorter disease-free survival and overexpression of PTEN protein linked to shorter disease-free and overall survival of patients with GBM. PTEN nonsense mutations correlated with decreased p53 and Gata3 protein levels and increased genomic instability in human GBM tissues. Expression of nonsense PTEN mutant decreased p53 and Gata3 levels, producing increased DNA damage both in vitro and in vivo. Mice carrying xenograft tumors with nonsense PTEN mutant displayed significantly shorter survival. Our data demonstrated the prognostic value of combined PTEN mutation and protein expression for patients with GBM and highlighted distinct biologic effects of nonsense and missense mutations of PTEN.

Nimotuzumab in combination with radiotherapy in high grade glioma patients: a single institution experience

Nimotuzumab, a humanized antibody targeting epidermal growth factor receptor, has potent anti-proliferative, anti-angiogenic, and pro-apoptotic effects in vitro and in vivo. It also reduces the number of radio-resistant CD133(+) glioma stem cells. The antibody has been extensively evaluated in patients with advanced head and neck, glioma, lung, esophageal, pancreatic, and gastric cancer. In this single institution experience, 35 patients with anaplastic astrocytoma (AA) or glioblastoma multiforme (GBM) were treated with irradiation and 200 mg doses of nimotuzumab. The first 6 doses were administered weekly, together with radiotherapy, and then treatment continued every 21 days until 1 year. The median number of doses was 12, and the median cumulative dose was thus 2400 mg of nimotuzumab. The most frequent treatment-related toxicities were increase in liver function tests, fever, nausea, anorexia, asthenia, dizziness, and tremors. These adverse reactions were classified as mild and moderate. The median survival time was 12.4 mo or 27.0 mo for patients with GBM or AA patients, respectively, who received curative-intent radiotherapy in combination with the antibody. The survival time of a matched population treated at the same hospital with irradiation alone was decreased (median 8.0 and 12.2 mo for GBM and AA patients, respectively) compared with that of the patients who received nimotuzumab and curative-intent radiotherapy. We have thus confirmed that nimotuzumab is a very well-tolerated drug, lacking cumulative toxicity after maintenance doses. This study, in a poor prognosis population, validates the previous data of survival gain after combining nimotuzumab and radiotherapy, in newly diagnosed high-grade glioma patients.

Suppression of tumorigenicity by microRNA-138 through inhibition of EZH2-CDK4/6-pRb-E2F1 signal loop in glioblastoma multiforme

Deregulation of microRNAs (miRNAs) is implicated in tumor progression. We attempt to identify the tumor suppressive miRNA not only down-regulated in glioblastoma multiforme (GBM) but also potent to inhibit the oncogene EZH2, and then investigate the biological function and pathophysiologic role of the candidate miRNA in GBM. In this study, we show that miRNA-138 is reduced in both GBM clinical specimens and cell lines, and is effective to inhibit EZH2 expression. Moreover, high levels of miR-138 are associated with long overall and progression-free survival of GBM patients from The Cancer Genome Atlas dataset (TCGA) data portal. Ectopic expression of miRNA-138 effectively inhibits GBM cell proliferation in vitro and tumorigenicity in vivo through inducing cell cycles G1/S arrest. Mechanism investigation reveals that miRNA-138 acquires tumor inhibition through directly targeting EZH2, CDK6, E2F2 and E2F3. Moreover, an EZH2-mediated signal loop, EZH2-CDK4/6-pRb-E2F1, is probably involved in GBM tumorigenicity, and this loop can be blocked by miRNA-138. Additionally, miRNA-138 negatively correlates to mRNA levels of EZH2 and CDK6 among GBM clinical samples from both TCGA and our small amount datasets. In conclusion, our data demonstrate a tumor suppressive role of miRNA-138 in GBM tumorigenicity, suggesting a potential application in GBM therapy.

Assessing current therapeutic approaches to decode potential resistance mechanisms in glioblastomas

Unique astrocytic cell infiltrating growth and glial tumor growth in the confined skull make human glioblastoma (GBM) one of the most difficult cancers to treat in modern medicine. Prognosis for patients is very poor, as they die more or less within 12 months. Patients either die of the cancer itself, or secondary complications such as cerebral edema, herniations, or hemorrhages. GBMs rarely metastasize to other organs. However, GBM recurrence associated with resistance to therapeutic drugs is common. Patients die shortly after relapse. GBM is indeed an outstanding cancer model to search for potential mechanisms for drug resistance. Here, we reviewed the current cancer biology of gliomas and their pathophysiological events that contribute to the development of therapeutic resistance. We have addressed the potential roles of cancer stem cells, epigenetic modifications, and epithelial mesenchymal transition (EMT) in the development of resistance to inhibitor drugs in GBMs. The potential role of TIAF1 (TGF-β-induced antiapoptotic factor) overexpression and generation of intratumor amyloid fibrils for conferring drug resistance in GBMs is discussed.

Interactions of miR-323/miR-326/miR-329 and miR-130a/miR-155/miR-210 as prognostic indicators for clinical outcome of glioblastoma patients

Background

Thailand faces a significant burden in terms of treating and managing degenerative and chronic diseases. Moreover, incidences of rare diseases are rising. Many of these—such as diabetes, cancer, and inherited inborn metabolic diseases—have no definite treatments or cure. Meanwhile, advanced health biotechnology has been found, in principle, to be an effective solution for these health problems.

Methods

Qualitative approaches were employed to analyse the current situation and examine existing public policies related to advanced health biotechnologies in Thailand. The results of this analysis were then used to formulate policy recommendations.

Results

Our research revealed that the system in Thailand in relation to advanced health biotechnologies is fragmented, with multiple unaddressed gaps, underfunding of research and development (R&D), and a lack of incentives for the private sector. In addition, there are no clear definitions of advanced health biotechnologies, and coverage pathways are absent. Meanwhile, false advertising and misinformation are prevalent, with no responsible bodies to actively and effectively provide appropriate information and education (I&E). The establishment of a specialised institution to fill the gaps in this area is warranted.

Conclusion

The development and implementation of a comprehensive national strategic plan related to advanced health biotechnologies, greater investment in R&D and I&E for all stakeholders, collaboration among agencies, harmonisation of reimbursement across public health schemes, and provision of targeted I&E are specifically recommended.

Interactions of miR-323/miR-326/miR-329 and miR-130a/miR-155/miR-210 as prognostic indicators for clinical outcome of glioblastoma patients

Background

Glioblastoma multiforme (GBM) is the most common and aggressive brain tumor with poor clinical outcome. Identification and development of new markers could be beneficial for the diagnosis and prognosis of GBM patients. Deregulation of microRNAs (miRNAs or miRs) is involved in GBM. Therefore, we attempted to identify and develop specific miRNAs as prognostic and predictive markers for GBM patient survival.

Methods

Expression profiles of miRNAs and genes and the corresponding clinical information of 480 GBM samples from The Cancer Genome Atlas (TCGA) dataset were downloaded and interested miRNAs were identified. Patients’ overall survival (OS) and progression-free survival (PFS) associated with interested miRNAs and miRNA-interactions were performed by Kaplan-Meier survival analysis. The impacts of miRNA expressions and miRNA-interactions on survival were evaluated by Cox proportional hazard regression model. Biological processes and network of putative and validated targets of miRNAs were analyzed by bioinformatics.

Results

In this study, 6 interested miRNAs were identified. Survival analysis showed that high levels of miR-326/miR-130a and low levels of miR-323/miR-329/miR-155/miR-210 were significantly associated with long OS of GBM patients, and also showed that high miR-326/miR-130a and low miR-155/miR-210 were related with extended PFS. Moreover, miRNA-323 and miRNA-329 were found to be increased in patients with no-recurrence or long time to progression (TTP). More notably, our analysis revealed miRNA-interactions were more specific and accurate to discriminate and predict OS and PFS. This interaction stratified OS and PFS related with different miRNA levels more detailed, and could obtain longer span of mean survival in comparison to that of one single miRNA. Moreover, miR-326, miR-130a, miR-155, miR-210 and 4 miRNA-interactions were confirmed for the first time as independent predictors for survival by Cox regression model together with clinicopathological factors: Age, Gender and Recurrence. Plus, the availability and rationality of the miRNA-interaction as predictors for survival were further supported by analysis of network, biological processes, KEGG pathway and correlation analysis with gene markers.

Conclusions

Our results demonstrates that miR-326, miR-130a, miR-155, miR-210 and the 4 miRNA-interactions could serve as prognostic and predictive markers for survival of GBM patients, suggesting a potential application in improvement of prognostic tools and treatments.

OSU-03012 interacts with lapatinib to kill brain cancer cells

We have further defined mechanism(s) by which the drug OSU-03012 (OSU) kills brain cancer cells. OSU toxicity was enhanced by the HSP90 inhibitor 17-N-Allylamino-17-demethoxygeldanamycin (17AAG) that correlated with reduced expression of ERBB1 and ERBB2. Inhibition of the extrinsic apoptosis pathway blocked the interaction between 17AAG and OSU. OSU toxicity was enhanced by the inhibitor of ERBB1/2/4, lapatinib. Knock down of ERBB1/2/4 in a cell line specific fashion promoted OSU toxicity. Combined exposure of cells to lapatinib and OSU resulted in reduced AKT and ERK1/2 activity; expression of activated forms of AKT and to a lesser extent MEK1 protected cells from the lethal effects of the drug combination. Knock down of PTEN suppressed, and expression of PTEN enhanced, the lethal interaction between OSU and lapatinib. Downstream of PTEN, inhibition of mTOR recapitulated the effects of lapatinib. Knock down of CD95, NOXA, PUMA, BIK or AIF, suppressed lapatinib and OSU toxicity. Knock down of MCL-1 enhanced, and overexpression of MCL-1 suppressed, drug combination lethality. Lapatinib and OSU interacted in vivo to suppress the growth of established tumors. Collectively our data argue that the inhibition of ERBB receptor function represents a useful way to enhance OSU lethality in brain tumor cells.