HOXD-AS2-STAT3 feedback loop attenuates sensitivity to temozolomide in glioblastoma.

AIMS: Glioblastoma multiforme (GBM) is the deadliest glioma and its resistance to temozolomide (TMZ) remains intractable. Long non-coding RNAs (lncRNAs) play crucial roles in that and this study aimed to investigate underlying mechanism of HOXD-AS2-affected temozolomide sensitivity in glioblastoma. METHODS: We analyzed and validated the aberrant HOXD-AS2 expression in glioma specimens. Then we explored the function of HOXD-AS2 in vivo and in vitro and a clinical case was also reviewed to examine our findings. We further performed mechanistic experiments to investigate the mechanism of HOXD-AS2 in regulating TMZ sensitivity. RESULTS: Elevated HOXD-AS2 expression promoted progression and negatively correlated with prognosis of glioma; HOXD-AS2 attenuated temozolomide sensitivity in vitro and in vivo; The clinical case also showed that lower HOXD-AS2 sensitized glioblastoma to temozolomide; STAT3-induced HOXD-AS2 could interact with IGF2BP2 protein to form a complex and sequentially upregulate STAT3 signaling, thus forming a positive feedback loop regulating TMZ sensitivity in glioblastoma. CONCLUSION: Our study elucidated the crucial role of the HOXD-AS2-STAT3 positive feedback loop in regulating TMZ sensitivity, suggesting that this could be provided as a potential therapeutic candidate of glioblastoma.

Multifocal glioblastoma-two case reports and literature review.

BACKGROUND: Multifocal glioblastoma is a rare type of glioblastoma with worse prognosis. In this article, we aimed to report two cases of classical multifocal glioblastoma. CASE PRESENTATION: In case 1, a 47-year-old male presented with dizziness, and once had a sudden loss of consciousness accompanied by convulsion of limbs. Contrast-enhanced MRI showed multiple lesions with heterogeneously ring-enhanced characters in the left hemisphere, diagnosed as multifocal glioblastoma. He underwent a craniotomy of all lesions, concurrent radiotherapy and chemotherapy as well as additional chemotherapy of temozolomide. After 2 cycles, repeat MRI showed that the new lesions already occurred and progressed. Eventually, he abandoned the chemotherapy after the 2 cycles and died 1 year later. In case 2, a 71-year-old male presented with a history of headache, left limb weakness, and numbness. Discontinuous convulsion of limbs once occurred. Contrast-enhanced MRI showed multiple lesions located in the right hemisphere, diagnosed as multifocal glioblastoma. He underwent a right frontoparietal craniotomy of the main lesion. Hemorrhage of the residual tumor and pulmonary artery embolism occurred synchronously. Eventually, his family decided not to pursue any further treatment and opted for hospice care and he passed away within 11 days of surgery. CONCLUSIONS: We reported two cases of typical multifocal glioblastoma. Valid diagnosis is crucial; then, resection of multiple lesions and canonical radio-chemotherapy probably bring survival benefits.

Bortezomib inhibits growth and sensitizes glioma to temozolomide (TMZ) via down-regulating the FOXM1-Survivin axis.

BACKGROUND: High-grade glioma (HGG) is a fatal human cancer. Bortezomib, a proteasome inhibitor, has been approved for the treatment of multiple myeloma but its use in glioma awaits further investigation. This study aimed to explore the chemotherapeutic effect and the underlying mechanism of bortezomib on gliomas. METHODS: U251 and U87 cell viability and proliferation were detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, tumor cell spheroid growth, and colony formation assay. Cell apoptosis and cell cycle were detected by flow cytometry. Temozolomide (TMZ)-insensitive cell lines were induced by long-term TMZ treatment, and cells with stem cell characteristics were enriched with stem cell culture medium. The mRNA levels of interested genes were measured via reverse transcription-quantitative polymerase chain reaction, and protein levels were determined via Western blotting/immunofluorescent staining in cell lines and immunohistochemical staining in paraffin-embedded sections. Via inoculating U87 cells subcutaneously, glioma xenograft models in nude mice were established for drug experiments. Patient survival data were analyzed using the Kaplan-Meier method. RESULTS: Bortezomib inhibited the viability and proliferation of U251 and U87 cells in a dose- and time-dependent manner by inducing apoptosis and cell cycle arrest. Bortezomib also significantly inhibited the spheroid growth, colony formation, and stem-like cell proliferation of U251 and U87 cells. When administrated in combination, bortezomib showed synergistic effect with TMZ in vitro and sensitized glioma to TMZ treatment both in vitro and in vivo. Bortezomib reduced both the mRNA and protein levels of Forkhead Box M1 (FOXM1) and its target gene Survivin. The FOXM1-Survivin axis was markedly up-regulated in established TMZ-insensitive glioma cell lines and HGG patients. Expression levels of FOXM1 and Survivin were positively correlated with each other and both related to poor prognosis in glioma patients. CONCLUSIONS: Bortezomib was found to inhibit glioma growth and improved TMZ chemotherapy efficacy, probably via down-regulating the FOXM1-Survivin axis. Bortezomib might be a promising agent for treating malignant glioma, alone or in combination with TMZ.

Expression profile of circular RNAs in IDH-wild type glioblastoma tissues.

OBJECTIVE: The aim of the present study is to investigate the expression profiles of circular RNAs (circRNAs) in IDH-wild type (IDH-wt) glioblastoma and explore the differences in circRNAs expression between IDH-wt glioblastoma and adjacent normal brain. PATIENTS AND METHODS: circRNA expression profiles were detected by circRNA microarray in three matched pairs of IDH-wt glioblastoma and adjacent normal brain. qRT-PCR was used to verify the differential expression of circRNAs from microarray analysis. Bioinformatics analysis was used to analyze potential functions of the differentially expressed circRNAs in IDH-wt glioblastoma. RESULTS: Compared with the adjacent normal brain tissues, 254 circRNAs were upregulated and 361 circRNAs were downregulated in IDH-wt glioblastoma with a ≥1.5-fold change. A total of 12 differentially expressed circRNAs were randomly selected and validated a good correlation of results from circRNA-seq with qRT-PCR. Gene Ontology (GO) analysis revealed the differentially expressed circRNAs possibly involved in cell division, DNA damage repair, cytoskeleton, and protein ubiquitination. 46 and 50 miRNAs were predicted to be adsorbed by the top 10 upregulated circRNAs and top 10 downregulated circRNAs, respectively. CONCLUSION: Differential expression of circRNAs may be associated with IDH-wt glioblastoma development and progression, and these circRNAs can be identified as biomarkers for prognosis prediction and targets for treatment.

CPEB4 regulates glioblastoma cell proliferation and predicts poor outcome of patients.

OBJECTIVE: Cytoplasmic polyadenylation element binding protein 4 (CPEB4) is a regulator of gene expression at transcriptional level and has been reported to be associated with biological malignancy in cancers. However, little was known about the correlation between CPEB4 and glioblastoma cell proliferation and the prognostic significance in patients. Our aim was to investigate the functional role and prognostic value of CPEB4 in glioblastoma. PATIENTS AND METHODS: We determined the expression of CPEB4 protein using immunohistochemistry in tissue microarrays containing 278 glioma patients (including 98 primary glioblastomas) and evaluated its association with pathological grades and clinical outcome by univariate and multivariate analyses. And then, lentiviral-mediated RNAi targeting CPEB4 was utilized to study the role of CPEB4 in glioblastoma cell proliferation. RESULTS: In our cohort, CPEB4 expression was positively related to glioma pathological grade (p < 0.01) and elevated in glioblastoma (p < 0.01). High expression of CPEB4 was associated with significantly poor prognosis, and could be identified as an independent risk factor for overall survival (OS) and progression-free survival (PFS) of glioblastoma patients (hazard ratio (HR) = 1.730, p = 0.014 and HR = 1.877, p = 0.004, respectively). In vitro studies further showed that downregulation of CPEB4 significantly reduced the growth rate of T98G and U251 cells comparing with the controls. CONCLUSION: Our study indicated that increased expression of CPEB4 in primary glioblastoma is a novel biomarker for predicting poor outcome of patients and suppression of CPEB4 inhibit tumor cell proliferation, suggesting a potential therapeutic target for glioblastoma.

Actin-capping protein CapG is associated with prognosis, proliferation and metastasis in human glioma.

Glioma is the most aggressive and malignant primary brain tumor in adults. In the present study, we identified a vital oncoprotein, capping actin protein, gelsolin-like (CapG), and investigated its roles in the prognosis, proliferation and metastasis in glioma. The mRNA and protein levels of CapG were significantly increased in human glioma, and higher CapG expression was an independent prognostic factor for predicting unfavorable prognosis. The expression level of CapG was found to be associated with several common molecular features of glioblastoma (GBM; WHO grade IV glioma) in The Cancer Genome Atlas (TCGA) cohort. When analyzing the prognosis of GBM patients according to these molecular features, we observed that the prognostic value of CapG was affected by amplification of CDK6 or EGFR. However, overexpression of CapG markedly promoted cell growth in vitro, while depletion of CapG significantly inhibited cell proliferation by blocking the cell cycle in G1/S transition. Moreover, CapG manipulation in glioma cell lines U87 and U251 showed CapG-dependent cellular migration and invasiveness. These data suggest that CapG may serve as a prognostic biomarker with potentially important therapeutic implications for glioma.

Overexpression of G-protein-coupled receptors 65 in glioblastoma predicts poor patient prognosis.

OBJECTIVE: G-protein-coupled receptors 65 (GPR65), identified as an acid-sensing receptor, is overexpressed in several malignancies and promote tumor development. Our aim was to investigate the expression and prognostic value of GPR65 in glioblastoma. MATERIALS AND METHODS: We determined the expression of GPR65 protein using immunohistochemistry in tissue microarrays containing 11 Grade I, 107 Grade II, 47 Grade III, and 102 Grade IV gliomas and 16 normal brains. Then we evaluated its association with pathological grades, prognosis, and recurrence. The Cancer Genome Atlas (TCGA) group (N=528) was further employed to examine transcriptional level of GPR65 in glioblastoma and the correlation between GPR65 expression and clinical outcome. RESULTS: In our cohort, GPR65 expression was positively related to glioma pathological grade (p<0.01) and elevated in glioblastoma (p<0.01). High expression of GPR65 was associated with significantly short overall survival (OS) (p=0.013) and progression-free survival (PFS) (p=0.029), and could be identified as an independent risk factor for OS of glioblastoma patients (Hazard Ratio [HR]=1.596, p=0.037). As an aiding evidence, increased GPR65 mRNA expression was also found in TCGA glioblastoma group (p<0.001) and its high level predicted a poor clinical outcome (OS, p=0.003; PFS, p=0.001). CONCLUSION: Our findings suggest that GPR65 is overexpressed in glioblastoma and its high expression predicts unfavorable clinical outcome for patients. Targeting GPR65 may serve as a potential therapy for treating glioblastoma.

Does Early Postsurgical Temozolomide Plus Concomitant Radiochemotherapy Regimen Have Any Benefit in Newly-diagnosed Glioblastoma Patients? A Multi-center, Randomized, Parallel, Open-label, Phase II Clinical Trial.

BACKGROUND: The radiochemotherapy regimen concomitantly employing temozolomide (TMZ) chemotherapy and radiotherapy (RT) 4 weeks after surgery, followed by 6 cycles of TMZ is a common treatment for glioblastoma (GBM). However, its median overall survival (OS) is only 14.6 months. This study was to explore the effectiveness and safety of early TMZ chemotherapy between surgery and chemoradiotherapy plus the standard concomitant radiochemotherapy regimen. METHODS: A randomized, parallel group, open-label study of 99 newly diagnosed GBM patients was conducted at 10 independent Chinese neurosurgical departments from June 2008 to June 2012. Patients were treated with concomitant radiochemotherapy regimen plus early postsurgical temozolomide (early TMZ group) or standard concomitant radiochemotherapy regimen (control group). Overall response was assessed based on objective tumor assessments, administration of corticosteroid and neurological status test. Hematological, biochemical, laboratory, adverse event (AE), and neurological condition were measured for 24 months of follow-up. The primary efficacy endpoint of this study was overall survival (OS). The secondary endpoint was progression free survival (PFS). RESULTS: The median OS time in the early TMZ group was 17.6 months, compared with 13.2 months in the control group (log-rank test P = 0.021). In addition, the OS rate in the early TMZ group was higher at 6, 12, and 18 months than in the control group, respectively (P < 0.05). The median PFS time was 8.7 months in the early TMZ group and 10.4 months in the control group (log-rank test P = 0.695). AEs occurred in 29 (55.8%) and 31(73.8%) patients respectively in early and control groups, including nausea (15.4% vs. 33.3%), vomiting (7.7% vs. 28.6%), fever (7.7% vs. 11.9%), and headache (3.8% vs. 23.8%). Only 30.8% and 33.3% were drug-related, respectively. CONCLUSIONS: Addition of TMZ chemotherapy in the early break of the standard concomitant radiochemotherapy regimen was well tolerated and significantly improved the OS of the GBM patients, compared with standard concomitant radiochemotherapy regimen. However, a larger randomized trial is warranted to verify these results.

[Surgical treatment of hemangioblastoma in medulla oblongata:a report of 12 cases].

OBJECTIVE: To explore the clinical characteristics, diagnostic strategies and surgical techniques of hemangioblastoma (HB) in medulla oblongata. METHODS: The clinical and radiological characteristics, therapeutic processes and outcomes of 12 HB cases treated at our department from 2002 to 2012 were studied by retrospective analysis. RESULTS: Headache, somatic numbness and limb muscle weakness were the major symptoms of oblongata HB. Magnetic resonance imaging before surgery revealed a total of 12 single tumors. Among these tumors, upper (n = 1), middle (n = 7) and lower (n = 4) parts of medulla oblongata were involved. The locations were surface (n = 9) and intramedullary (n = 3). Three tumors had cyst. Digital subtraction angiography (DSA) was performed on 5 cases and it revealed that the main blood supply arteries of tumors were branches of posterior inferior cerebellar artery (PICA) and anterior inferior cerebellar artery (AICA).One case underwent pre-surgical embolism during angiography. Eleven tumors were totally resected and 1 was fulgurized.Symptoms improved (n = 8) and worsened (n = 2). And two patients died. All survivors were followed up for 3 months to 10 years and had a McCormick functional grading of I-II.One case relapsed 7 year later. CONCLUSION: For Cystic HB, small or medium sized substantial HB in middle and lower part of oblongata, surgical removal is often safe and symptoms may be lessened.It can be used as a first-line treatment. For large ( ≥ 3 cm) substantial HB or HB in upper part of oblongata, serious postoperative complications such as respiratory failure, neurogenic pulmonary edema or acute obstructive hydrocephalus may occur. Thus surgical resection should be prudently considered and possible consequences thoroughly discussed with the patients.