Upregulated miRNA-622 inhibited cell proliferation, motility, and invasion via repressing Kirsten rat sarcoma in glioblastoma

The RAS oncogene in brain tumors and the involvement of let-7 microRNA

RAS oncogenes are master regulator genes in many cancers. In general, RAS-driven cancers have an oncogenic RAS mutation that promotes disease progression (colon, lung, pancreas). In contrast, brain tumors are not necessarily RAS-driven cancers because RAS mutations are rarely observed. In particular, glioblastomas (the most lethal brain tumor) do not appear to have dominant genetic mutations that are suitable for targeted therapy. Standard treatment for most brain tumors continues to focus on maximal surgical resection, radiotherapy and chemotherapy. Yet the convergence of genomic aberrations such as EGFR, PDGFR and NF1 (some of which are clinically effective) with activation of the RAS/MAPK cascade is still considered a key point in gliomagenesis, and KRAS is undoubtedly a driving gene in gliomagenesis in mice. In cancer, microRNAs (miRNA) are small, non-coding RNAs that regulate carcinogenesis. However, the functional consequences of aberrant miRNA expression in cancer are still poorly understood. let-7 encodes an intergenic miRNA that is classified as a tumour suppressor, at least in lung cancer. Let-7 suppresses a plethora of oncogenes such as RAS, HMGA, c-Myc, cyclin-D and thus suppresses cancer development, differentiation and progression. let-7 family members are direct regulators of certain RAS family genes by binding to the sequences in their 3'untranslated region (3'UTR). let-7 miRNA is involved in the malignant behaviour in vitro-proliferation, migration and invasion-of gliomas and stem-like glioma cells as well as in vivo models of glioblastoma multiforme (GBM) via KRAS inhibition. It also increases resistance to certain chemotherapeutic agents and radiotherapy in GBM. Although let-7 therapy is not yet established, this review updates the current state of knowledge on the contribution of miRNA let-7 in interaction with KRAS to the oncogenesis of brain tumours.

Propofol inhibits glioma progression by regulating circMAPK4/miR-622/HOXA9 axis

Propofol has a tumor-suppressive role in glioma, but the mechanism by which propofol is involved in glioma progression is largely unknown. This study aims to explore a potential circular RNAs (circRNAs)/microRNAs (miRNAs)/mRNA network in response to Propofol in glioma. Human glioma cell lines (U251 and LN229) were suffered from Propofol treatment (5 μg/mL for 24 h) and transfection. circRNA mitogen-activated protein kinase 4 (circMAPK4), miR-622, homeobox A9 (HOXA9) abundances were determined by quantitative reverse transcription polymerase chain reaction and western blot. Migration and invasion were analyzed via transwell analysis. Cell proliferation was evaluated using Cell Counting Kit-8 and colony formation analysis. Cell apoptosis and related protein expression were determined via flow cytometry and western blot. Target relationship was assessed via dual-luciferase reporter analysis, RNA pull-down and RNA immunoprecipitation. Propofol reduced circMAPK4 expression. Propofol inhibited cell proliferation, migration and invasion, while increased apoptosis via decreasing circMAPK4 in glioma cells. miR-622 was targeted via circMAPK4. circMAPK4 knockdown decreased glioma cell growth, migration and invasion by up-regulating miR-622. miR-622 knockdown reversed the effect of Propofol on glioma progression. HOXA9 was targeted by miR-622, and its expression was decreased by Propofol treatment. miR-622 overexpression restrained glioma progression via decreasing HOXA9. Propofol regulated circMAPK4/miR-622/HOXA9 axis in glioma cells. Propofol constrains glioma progression by regulating circMAPK4/miR-622/HOXA9 axis in vitro. Propofol restrains glioma cell growth, migration and invasion. circMAPK4 can regulate HOXA9 by sponging miR-622 in glioma cells. Propofol represses glioma progression via a circMAPK4/miR-622/HOXA9 axis.

The expression and function of miR-622 in a variety of tumors

Cancer is a heavy burden worldwide, with high morbidity and mortality rates. Cancer treatments currently involve surgical and nonsurgical approaches. Molecular targeted therapy is the latest breakthrough. miRNAs are small noncoding RNAs found in plants and animals that play a role in cancer and various diseases through influencing numerous biological processes, such as cell proliferation, apoptosis, the immune response, and drug resistance. One miRNA, miR-622, has been shown to regulate various pathways to influence disease processes. Abnormal miR-622 expression can promote or inhibit liver, colorectal, and breast cancers and other tumors, such as glioma. Herein, we reviewed the expression levels and clinical effects of miR-622 in various tumors and summarized its mechanisms and related molecules.

MiR-142 suppresses progression of gastric carcinoma via directly targeting LRP8

Recently, the role of miRNA-142 (miR-142) in tumor development has attracted extensive attention. The aim of this study was to investigate the impact of miR-142 and its potential target low-density lipoprotein receptor (LDLR)-related protein 8 (LRP8) on the proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) of gastric carcinoma (GC). Gene and protein expressions were detected using RT-qPCR and Western blotting, respectively. The biological behaviors of GC cell lines were determined by CCK-8, flow cytometry and Transwell assays, respectively. The interaction between miR-142 and LRP8 was confirmed with dual luciferase reporter assay. Xenograft nude mouse model was used to observe tumor growth. Here, miR-142 expression was markedly reduced in GC tissues and cells, and was negatively correlated with lymph node metastasis and poor prognosis in patients with GC. Stable miR-142 overexpression was sufficient to inhibit cell proliferation, migration and invasion in vitro and reduce tumor growth in vivo, accompanied by increased expression of the epithelial marker and reduced levels of mesenchymal markers. Mechanistically, the 3'-untranslated regions (3'-UTR) of LRP8 was a direct target of miR-142. Restoration of LRP8 attenuated the inhibitory effect of miR-142 on GC cells, whereas inhibition of LRP8 caused the opposite outcomes. In conclusion, our findings suggest that miR-142 plays a significant role in suppressing progression of GC by targeting LRP8, and miR-142 may be useful for the development of novel targeted therapies.

Polymorphism in miRNA target sites of CEP-63 and CEP-152 ring complex influences expression of CEP genes and favors tumorigenesis in glioma

Purpose: The present study was designed to screen the genetic polymorphisms and expression profiling of CEP-152 and CEP-63 genes in brain tumor patients. Methods: The amplification refractory mutation system PCR technique (ARMS-PCR) was used for mutation analysis using 300 blood samples of brain tumor patients and 300 overtly healthy controls. For expression analysis, 150 brain tumor tissue samples along with adjacent uninvolved/normal tissues (controls) were collected. Results: A significantly higher frequency of the mutant genotype of the CEP-152 single nucleotide polymorphism (rs2169757) and CEP-63 single nucleotide polymorphisms (rs9809619 and rs13060247) was observed in patients versus overtly healthy controls. The authors' results showed highly significant deregulation of CEP-152 (p < 0.0001) and CEP-63 (p < 0.0001) in glioma/meningioma tumor tissues versus adjacent normal tissue. Conclusion: The present study showed that variations in CEP-152 and CEP-63 genes were associated with an increased risk of brain tumor.

miRNA signature in glioblastoma: Potential biomarkers and therapeutic targets

MicroRNAs (miRNAs) are transcripts with sizes of about 22 nucleotides, which are produced through a multistep process in the nucleus and cytoplasm. These transcripts modulate the expression of their target genes through binding with certain target regions, particularly 3' suntranslated regions. They are involved in the pathogenesis of several kinds of cancers, such as glioblastoma. Several miRNAs, including miR-10b, miR-21, miR-17-92-cluster, and miR-93, have been up-regulated in glioblastoma cell lines and clinical samples. On the other hand, expression of miR-7, miR-29b, miR-32, miR-34, miR-181 family members, and a number of other miRNAs have been decreased in this type of cancer. In the current review, we explain the role of miRNAs in the pathogenesis of glioblastoma through providing a summary of studies that reported dysregulation of these epigenetic effectors in this kind of brain cancer.

Predictive Relevance of Circulating miR-622 in Patients with Newly Diagnosed and Recurrent High-Grade Serous Ovarian Carcinoma

BACKGROUND

Identifying patients with high-grade serous ovarian cancer (HGSOC) who will respond to treatment remains a clinical challenge. We focused on miR-622, a miRNA involved in the homologous recombination repair (HRR) pathway, and we assessed its predictive value in serum prior to first-line chemotherapy and at relapse.

METHODS

Serum miR-622 expression was assessed in serum prior to first-line platinum-based chemotherapy in a prospective multicenter study (miRNA Serum Analysis, miRSA, NCT01391351) and a retrospective cohort (Biological Resource Center, BRC), and was also studied at relapse. Progression-free survival (PFS) and overall survival (OS) were used as primary and secondary endpoints prior to first-line chemotherapy and OS as a primary endpoint at relapse.

RESULTS

The group with high serum miR-622 expression was associated with a significantly lower PFS (15.4 versus 24.4 months; adjusted HR 2.11, 95% CI 1.2 3.8, P = 0.015) and OS (29.7 versus 40.6 months; adjusted HR 7.68, 95% CI 2.2-26.2, P = 0.0011) in the miRSA cohort. In the BRC cohort, a high expression of miR-622 was also associated with a significantly lower OS (22.8 versus 35.9 months; adjusted HR 1.98, 95% CI 1.1-3.6, P = 0.026). At relapse, high serum miR-622 was associated with a significantly lower OS (7.9 versus 20.6 months; adjusted HR 3.15, 95% CI 1.4-7.2, P = 0.0062). Serum miR-622 expression is a predictive independent biomarker of response to platinum-based chemotherapy for newly diagnosed and recurrent HGSOC.

CONCLUSIONS

These results may open new perspectives for HGSOC patient stratification and monitoring of resistance to platinum-based and poly(ADP-ribose)-polymerase-inhibitor-maintenance therapies, facilitating better and personalized treatment decisions.

LncRNA SAMMSON overexpression distinguished glioblastoma patients from patients with diffuse neurosarcoidosis

The MRI characteristics of diffuse neurosarcoidosis are similar to those of glioblastoma. Therefore, identification of novel biomarkers to distinguish these two diseases is needed. We found that lncRNA Survival Associated Mitochondrial Melanoma-Specific Oncogenic Non-Coding RNA (SAMMSON) was upregulated in plasma of glioblastoma patients but not in diffuse neurosarcoidosis patients comparing to healthy controls. Upregulated SAMMSON distinguished glioblastoma patients from diffuse neurosarcoidosis patients and healthy controls. MiR-622 in glioblastoma patients was inversely correlated with SAMMSON. SAMMSON overexpression caused the downregulated expression of miR-622 in glioblastoma cells, while miR-622 overexpression did not affect SAMMSON expression. SAMMSON overexpression mediated the increased proliferation rate of glioblastoma cells. MiR-622 overexpression played an opposite role and reduced the effects of SAMMSON overexpression. Therefore, plasma SAMMSON has diagnostic value for glioblastoma and SAMMSON overexpression may promote glioblastoma cell proliferation by downregulating miR-622.

Low microRNA-622 expression predicts poor prognosis and is associated with ZEB2 in glioma

Background

MicroRNAs have been recently reported to play an important role in tumorigenesis and progression in several forms of tumors. Previous studies have shown that microRNA-622 (miR-622) was associated with glioma proliferation and invasion. However, the clinical significance of miR-622 in glioma has not been elucidated. The aim of our study was to investigate the clinical values of miR-622, as well as investigate the potential molecular mechanisms in glioma.

Materials and methods

qRT-PCR and Western blot analysis were used to analyze the expression of miR-622 and ZEB2, respectively. Kaplan–Meier analysis and Cox’s proportional hazards model were used in survival analysis. MTT assay, wound healing assay, transwell assay and flow cytometry analysis were carried out to detect the impact of miR-622 on glioma cell proliferation, migration, invasion and apoptosis.

Results

Our result indicated that miR-622 expression was greatly decreased in glioma tissues and cell lines and the downregulation of miR-622 was significantly associated with the advanced pathological grade and low Karnofsky performance score of glioma. In addition, Kaplan–Meier curves with log-rank analysis revealed a close correlation between downregulation of miR-622 expression and low overall survival rate in glioma patients. Furthermore, Cox regression analysis demonstrated that downregulated miR-622 could be considered as an independent poor prognostic indicator in glioma patients. Finally, our findings demonstrated that miR-622 overexpression remarkably suppressed glioma cell proliferation, migration and invasion, while facilitated apoptosis by suppressing ZEB2 in vitro.

Conclusion

Our study suggested that miR-622 may be identified as a valuable prognostic biomarker and a promising therapeutic target for glioma patients.

Screening for Differentially Expressed Circular RNAs in the Cartilage of Osteoarthritis Patients for Their Diagnostic Value

Background: Osteoarthritis (OA) is the most prevalent osteoarticular disease, which typically involves chronic cartilage degeneration and synovitis. The latest research shows that circular RNAs (circRNAs) play a role in the development of a variety of diseases, including osteoarthrosis. Purposes: The aim of this study was to explore the expression of circRNAs in OA chondrocytes and predict biomarkers for diagnosis. Materials and Methods: The circRNA expression profile was analyzed through use of the Gene Spring software V13.0; differentially expressed circRNAs were screened by comparing OA chondrocytes and normal articular chondrocytes. We validated the microarray data by quantitative real-time polymerase chain reaction analyses of OA chondrocytes and chondrocytes from normal controls. TargetScan software and miRanda software were used to predict networks of circRNA-miRNA interactions in cartilage. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology (GO) analyses were applied to predict the functions of differentially expressed circRNAs. Results: Overall, 1380 circRNAs were differentially expressed between OA chondrocytes and normal articular chondrocytes (fold-change ≥2, p ≤ 0.05), including 215 that were upregulated and 1165 that were downregulated circRNAs. After analyzing the differentially expressed circRNA genes, the top 20 enriched GO entries and KEGG pathways were annotated. The hsa_circrna_0032131 was identified for further analysis. A circRNA-miRNA network was constructed to represent the 10 most likely target genes associated with the validated circRNA. Conclusions: Our research suggests that some of the differentially expressed circRNAs in OA chondrocytes compared to normal chondrocytes are etiologically associated with the pathological process of OA. It was found that hsa_circRNA_0032131 likely participates in the initiation and progression of OA and has potential as a diagnostic marker. Clinical Relevance: To analyze the difference of circRNA expression profiles between OA and normal controls and explore biomarkers for diagnosis.

MicroRNA-181 inhibits glioblastoma cell growth by directly targeting CCL8

MicroRNAs (miRNAs/miRs), including miR-181, are closely linked to the development and progression of glioblastoma. However, the function of miR-181 in glioblastoma has not been fully clarified. The aim of the present study was to investigate the role of miR-181 in glioblastoma. miR-181 was revealed to be downregulated in glioblastoma tissues and cell lines, and associated with poor prognosis in patients with glioblastoma. Overexpression of miR-181 inhibited glioblastoma cell proliferation, invasion and migration, arrested glioblastoma cell cycle in the G1 phase and induced glioblastoma cell apoptosis. miR-181 was demonstrated to decrease expression of C-C motif chemokine ligand 8 (CCL8) by directly interacting with its 3′-untranslated region. Overexpression of CCL8 inversely reversed the proliferation, invasion and migration-promoting effects of miR-181 in glioblastoma cells. Furthermore, CCL8 was upregulated in glioblastoma tissues and was negatively correlated with miR-181 expression. These results indicate that miR-181 is a potential molecular biomarker or therapeutic target in the clinical management of glioblastoma.

Insulin promotes invasion and migration of KRASG12D mutant HPNE cells by upregulating MMP-2 gelatinolytic activity via ERK- and PI3K-dependent signalling

Objectives

Hyperinsulinemia is a risk factor for pancreatic cancer, but the function of insulin in carcinogenesis is unclear, so this study aimed to elucidate the carcinogenic effects of insulin and the synergistic effect with the KRAS mutation in the early stage of pancreatic cancer.

Materials and methods

A pair of immortalized human pancreatic duct‐derived cells, hTERT‐HPNE E6/E7/st (HPNE) and its oncogenic KRAS^G12D variant, hTERT‐HPNE E6/E7/KRAS^G12D/st (HPNE‐mut‐KRAS), were used to investigate the effect of insulin. Cell proliferation, migration and invasion were assessed using Cell Counting Kit‐8 and transwell assays, respectively. The expression of E‐cadherin, N‐cadherin, vimentin and matrix metalloproteinases (MMP‐2, MMP‐7 and MMP‐9) was evaluated by Western blotting and/or qRT‐PCR. The gelatinase activity of MMP‐2 and MMP‐9 in conditioned media was detected using gelatin zymography. The phosphorylation status of AKT, GSK3β, p38, JNK and ERK1/2 MAPK was determined by Western blotting.

Results

The migration and invasion ability of HPNE cells was increased after the introduction of the mutated KRAS gene, together with an increased expression of MMP‐2. These effects were further enhanced by the simultaneous administration of insulin. The use of MMP‐2 siRNA confirmed that MMP‐2 was involved in the regulation of cell invasion. Furthermore, there was a concentration‐ and time‐dependent increase in gelatinase activity after insulin treatment, which could be reversed by an insulin receptor tyrosine kinase inhibitor (HNMPA‐(AM)₃). In addition, insulin markedly enhanced the phosphorylation of PI3K/AKT, p38, JNK and ERK1/2 MAPK pathways, with wortmannin or LY294002 (a PI3K‐specific inhibitor) and PD98059 (a MEK1‐specific inhibitor) significantly inhibiting the insulin‐induced increase in MMP‐2 gelatinolytic activity.

Conclusions

Taken together, these results suggest that insulin induced migration and invasion in HPNE and HPNE‐mut‐KRAS through PI3K/AKT and ERK1/2 activation, with MMP‐2 gelatinolytic activity playing a vital role in this process. These findings may provide a new therapeutic target for preventing carcinogenesis and the evolution of pancreatic cancer with a background of hyperinsulinemia.

Aberrant miRNAs Regulate the Biological Hallmarks of Glioblastoma

GBM is the highest incidence in primary intracranial malignancy, and it remains poor prognosis even though the patient is gave standard treatment. Despite decades of intense research, the complex biology of GBM remains elusive. In view of eight hallmarks of cancer which were proposed in 2011, studies related to the eight biological capabilities in GBM have made great progress. From these studies, it can be inferred that miRs, as a mode of post-transcriptional regulation, are involved in regulating these malignant biological hallmarks of GBM. Herein, we discuss state-of-the-art research on how aberrant miRs modulate the eight hallmarks of GBM. The upregulation of 'oncomiRs' or the genetic loss of tumor suppressor miRs is associated with these eight biological capabilities acquired during GBM formation. Furthermore, we also discuss the applicable clinical potential of these research results. MiRs may aid in the diagnosis and prognosis of GBM. Moreover, miRs are also therapeutic targets of GBM. These studies will develop and improve precision medicine for GBM in the future.

miR‑454‑3p suppresses cell migration and invasion by targeting CPEB1 in human glioblastoma

MicroRNAs (miRNA/miRs) serve crucial roles in the progression of human glioblastoma (GBM); however, the exact regulatory mechanisms of miRNAs in human GBM remain unclear. The present study aimed to investigate the roles of miR‑454‑3p in human GBM. Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) analysis was performed to examine the expression of miR‑454‑3p in glioma tissues and adjacent tissues. Human GBM cell lines (LN‑229, A172 and GL15) and a normal human astrocyte cells (HA1800) were used for analysis. In addition, RT‑qPCR and western blotting were applied for mRNA and protein expression analysis, respectively. The cell proliferation was measured using a Cell Counting kit‑8 assay. Furthermore, scratch and Transwell assays were employed for the analysis of cell migration and invasion. A luciferase reporter assay was used to verify the target of miR‑454‑3p. The results revealed that miR‑454‑3p was downregulated in the glioma tissues and GBM cell lines, including LN‑229, A172 and GL15. Additionally, the overexpression of miR‑454‑3p significantly suppressed the proliferation, migration and invasion of LN‑229 cells. Furthermore, cytoplasmic polyadenylation element‑binding protein 1 (CPEB1) was confirmed as a direct target of miR‑454‑3p. These findings indicated that the overexpression of miR‑454‑3p inhibited cell proliferation, migration and invasion by downregulating CPEB1. Therefore, miR‑454‑3p may act as a tumor suppressor and represent an effective therapeutic strategy in GBM.

MicroRNA-622 is a novel mediator of tumorigenicity in melanoma by targeting Kirsten rat sarcoma

The network of molecular players is similar when comparing neural crest-derived, actively migrating melanoblasts to melanoma cells. However, melanoblasts are sensitive to differentiation-initiating signals at their target site (epidermis), while melanoma cells maintain migratory and undifferentiated features. We aimed at identifying downregulated genes in melanoma that are particularly upregulated in melanoblasts. Loss of such genes could contribute to stabilization of a dedifferentiated, malignant phenotype in melanoma. We determined that microRNA-622 (miR-622) expression was strongly downregulated in melanoma cells and tissues compared to melanocytes and melanoblast-related cells. miR-622 expression correlated with survival of patients with melanoma. miR-622 re-expression inhibited clonogenicity, proliferation, and migration in melanoma. Inhibition of miR-622 in melanocytes induced enhanced migration. Kirsten rat sarcoma (KRAS) was identified as a major functional target of miR-622 in melanoma. We conclude that miR-622 is a novel tumor suppressor in melanoma and identify the miR-622-KRAS axis as potential therapeutic target.

miR-622 suppresses tumor formation by directly targeting VEGFA in papillary thyroid carcinoma

Background

MicroRNAs (miRNAs) were reportedly to play crucial roles in papillary thyroid carcinoma (PTC) tumorigenesis and development. Therefore, the discovery of miRNAs may provide a new and powerful tool for diagnosis and treatment of PTC.

Purpose

The aim of this study was to investigate the biological function and underlying mechanism of miR-622 in PTC.

Materials and methods

The expression levels of miR-622 in PTC patient tissues and cell lines were determined by quantitative RT-PCR (qRT-PCR). The biological function including cell proliferation, colony formation, migration and invasion, as well as underling mechanism of miR-622 in PTC, were also evaluated by a series of in vitro and in vivo experiments.

Results

miR-622 expression level was significantly downregulated in PTC tissues and cell lines. Decreased miR-622 expression was associated with advanced clinical stage and lymph node metastasis (P<0.01). The overexpression of miR-622 in TPC-1 cells inhibited cell proliferation, migration and invasion in vitro, as well as suppress tumor growth in vivo. Moreover, we also demonstrated that miR-622 specifically targeted the 3'-UTR regions of vascular endothelial growth factor A (VEGFA) and inhibited its expression both mRNA level and protein levels. Overexpression of VEGFA reversed miR-622-mediated inhibition effect on cell proliferation, migration and invasion in thyroid cancer cells. More importantly, VEGFA expression was significantly increased and inversely correlated with the levels of miR-622 in PTC tissues.

Conclusion

These results show that miR-622 acts as a tumor suppressor in thyroid cancer, at least in part, via targeting VEGFA, and suggest that miR-622 may serves as a potential target for treatment of thyroid cancer patients.

Expression of microRNAs in tumors of the central nervous system in pediatric patients in México

PURPOSE

MicroRNAs were identified as molecules that participate in gene regulation; alterations in their expression characterize central nervous system (CNS). Information in pediatrics is scarce, so the objective of this work was to determine and then compare the patterns of expression of microRNAs in astrocytomas, ependymomas, and medulloblastomas, as well as in non-neoplastic brain.

METHODS

Low-density arrays were utilized to evaluate 756 microRNAs in three samples of each type of tumor and non-neoplastic brain. The relative expression was calculated in order to identify the three microRNAs whose expression was modified notably. This was verified using RT-qPCR in more number of tumor samples.

RESULTS

The microRNAs selected for testing were miR-100-5p, miR-195-5p, and miR-770-5p. A higher expression of miR-100-5p was observed in the astrocytomas and ependymomas compared to the medulloblastomas: on average 3.8 times (p < 0.05). MiR-770-5p was expressed less in medulloblastomas compared to astrocytomas four times (p = 0.0162). MiR-195-5p had a low expression in medulloblastomas compared to non-neoplastic cerebellum (p = 0.049). In all three tumor types, expression of miR-770-5p was lower than in non-neoplastic brain (p < 0.001).

CONCLUSIONS

These microRNAs may represent potential markers in these tumors.

Aspartate-β-hydroxylase (ASPH): A potential therapeutic target in human malignant gliomas

BACKGROUND

Despite therapeutic advances, survival with glioblastoma multiforme (GBM) remains below 15 months from diagnosis due to GBM's highly infiltrative nature which precludes complete surgical resection. Patient outcomes could potentially be improved by targeting genes and pathways that drive neoplastic cell motility and invasiveness, including hypoxia-inducible factor-1 (HIF-1α), NOTCH, and aspartate-β-hydroxylase (ASPH).

METHODS

Human astrocytoma biopsy specimens (n = 37), WHO Grades II-IV, were analyzed for levels and distributions of ASPH and HIF-1α immunoreactivity by immunohistochemical staining, and ASPH, Notch, JAG, HES1, HEY1 and HIF1α mRNA expression by quantigene multiplex analysis. The effects of small molecule inhibitors on ASPH's catalytic activity, cell viability and directional motility were examined in vitro in established GBM cell lines and primary tumor cells from an invasive mouse model of GBM.

RESULTS

The highest grade astrocytoma, i.e. GBM was associated with the highest levels of ASPH and HIF1α, and both proteins were more abundantly distributed in hypoxic compared with normoxic regions of tumor. Furthermore, mining of the TCGA database revealed higher levels of ASPH expression in the mesenchymal subtype of GBM, which is associated with more aggressive and invasive behavior. In contrast, lower grade astrocytomas had low expression levels of ASPH and HIF1α. In vitro experiments demonstrated that small molecule inhibitors targeting ASPH's catalytic activity significantly reduced GBM viability and directional motility. Similar effects occurred in GBM cells that were transduced with a lentiviral sh-ASPH construct.

CONCLUSION

This study demonstrates that increased ASPH expression could serve as a prognostic biomarker of gliomas and may assist in assigning tumor grade when biopsy specimens are scant. In addition, the findings suggest that GBM treatment strategies could be made more effective by including small molecule inhibitors of ASPH.