Targeting ARNT attenuates chemoresistance through destabilizing p38α-MAPK signaling in glioblastoma.

Glioblastoma (GBM) is the most aggressive and lethal brain tumor in adults. This study aimed to investigate the functional significance of aryl hydrocarbon receptor nuclear translocator (ARNT) in the pathogenesis of GBM. Analysis of public datasets revealed ARNT is upregulated in GBM tissues compared to lower grade gliomas or normal brain tissues. Higher ARNT expression correlated with the mesenchymal subtype and poorer survival in GBM patients. Silencing ARNT using lentiviral shRNAs attenuated the proliferative, invasive, and stem-like capabilities of GBM cell lines, while ARNT overexpression enhanced these malignant phenotypes. Single-cell RNA sequencing uncovered that ARNT is highly expressed in a stem-like subpopulation and is involved in regulating glycolysis, hypoxia response, and stress pathways. Mechanistic studies found ARNT activates p38 mitogen-activated protein kinase (MAPK) signaling to promote chemoresistance in GBM cells. Disrupting the ARNT/p38α protein interaction via the ARNT PAS-A domain restored temozolomide sensitivity. Overall, this study demonstrates ARNT functions as an oncogenic driver in GBM pathogenesis and represents a promising therapeutic target.

The Efficacy and Safety of Intraoperative Radiotherapy in the Treatment of Recurrent High-Grade Glioma: A Single-Center Prospective Study.

BACKGROUND: High-grade gliomas are treated following a standard protocol; however, tumor recurrence is almost inevitable. Recurrent high-grade gliomas have an extremely poor prognosis, and there are no clear treatment guidelines. In this stud, we evaluated the safety and effectiveness of intraoperative radiotherapy (IORT) for recurrent high-grade glioma. METHODS: In this prospective randomized study begun in April 2018, patients ≥18 years of age with a Karnofsky Performance Status >50 and recurrent high-grade glioma were randomly assigned in a 1:1 ratio to tumor resection and IORT or tumor resection alone. RESULTS: Twenty-two patients were allocated to the IORT group and 21 to receive surgery only (operation group). Clinical data of 42 enrolled patients were involved in the analysis. The progression-free survival of the IORT group was 9.6 months and of the operation group was 7.3 months (P = 0.018), and the overall survival of the 2 groups was 13.5 months and 10.2 months, respectively (P = 0.054). Univariate and multivariate analysis indicated that preoperative Karnofsky Performance Status >70 and IORT were protective factors for patients with recurrent high-grade glioma. A patient who underwent conventional fractionated radiotherapy within 6 months of receiving IORT died on the ninth day after undergoing tumor resection and IORT because of severe cerebral edema. The total operation time was longer in the IORT group, but there were no differences in intraoperative bleeding or adverse events between the 2 groups. CONCLUSIONS: IORT with low-energy radiography at a dose of 30-40 Gy is generally safe and effective for patients with recurrent glioma. However, IORT should not be performed for patients who have received conventional fractionated radiotherapy within 6 months.

NEK2 enhances malignancies of glioblastoma via NIK/NF-κB pathway.

Glioblastoma (GBM) is one of the most lethal primary brain tumor with a poor median survival less than 15 months. Despite the development of the clinical strategies over the decades, the outcomes for GBM patients remain dismal due to the strong proliferation and invasion ability and the acquired resistance to radiotherapy and chemotherapy. Therefore, developing new biomarkers and therapeutic strategies targeting GBM is in urgent need. In this study, gene expression datasets and relevant clinical information were extracted from public cancers/glioma datasets, including TCGA, GRAVENDEEL, REMBRANDT, and GILL datasets. Differentially expressed genes were analyzed and NEK2 was picked as a candidate gene for subsequent validation. Human tissue samples and corresponding data were collected from our center and detected by immunohistochemistry analysis. Molecular biological assays and in vivo xenograft transplantation were performed to confirm the bioinformatic findings. High-throughput RNA sequencing, followed by KEGG analysis, GSEA analysis and GO analysis were conducted to identify potential signaling pathways related to NEK2 expression. Subsequent mechanism assays were used to verify the relationship between NEK2 and NF-κB signaling. Overall, we identified that NEK2 is significantly upregulated in GBM and the higher expression of NEK2 exhibited a poorer prognosis. Functionally, NEK2 knockdown attenuated cell proliferation, migration, invasion, and tumorigenesis of GBM while NEK2 overexpression promoted the GBM progression. Furthermore, High-throughput RNA sequencing and bioinformatics analysis indicated that NEK2 was positively related to the NF-κB signaling pathway in GBM. Mechanically, NEK2 activated the noncanonical NF-κB signaling pathway by phosphorylating NIK and increasing the activity and stability of NIK. In conclusion, NEK2 promoted the progression of GBM through activation of noncanonical NF-κB signaling, indicating that NEK2- NF-κB axis could be a potential drug target for GBM.

Preoperative Prediction Nomogram Based on Integrated Profiling for Glioblastoma Multiforme in Glioma Patients.

Introduction: Traditional classification that divided gliomas into glioblastoma multiformes (GBM) and lower grade gliomas (LGG) based on pathological morphology has been challenged over the past decade by improvements in molecular stratification, however, the reproducibility and diagnostic accuracy of glioma classification still remains poor. This study aimed to establish and validate a novel nomogram for the preoperative diagnosis of GBM by using integrated data combined with feasible baseline characteristics and preoperative tests. Material and method: The models were established in a primary cohort that included 259 glioma patients who had undergone surgical resection and were pathologically diagnosed from March 2014 to May 2016 in the First Affiliated Hospital of Xi'an Jiaotong University. The preoperative data were used to construct three models by the best subset regression, the forward stepwise regression, and the least absolute shrinkage and selection operator, and to furthermore establish the nomogram among those models. The assessment of nomogram was carried out by the discrimination and calibration in internal cohorts and external cohorts. Results and discussion: Out of all three models, model 2 contained eight clinical-related variables, which exhibited the minimum Akaike Information Criterion (173.71) and maximum concordance index (0.894). Compared with the other two models, the integrated discrimination index for model 2 was significantly improved, indicating that the nomogram obtained from model 2 was the most appropriate model. Likewise, the nomogram showed great calibration and significant clinical benefit according to calibration curves and the decision curve analysis. Conclusion: In conclusion, our study showed a novel preoperative model that incorporated clinically relevant variables and imaging features with laboratory data that could be used for preoperative prediction in glioma patients, thus providing more reliable evidence for surgical decision-making.

Loss of PLK2 induces acquired resistance to temozolomide in GBM via activation of notch signaling.

BACKGROUND: Glioblastoma (GBM) is a lethal type of primary brain tumor with a median survival less than 15 months. Despite the recent improvements of comprehensive strategies, the outcomes for GBM patients remain dismal. Accumulating evidence indicates that rapid acquired chemoresistance is the major cause of GBM recurrence thus leads to worse clinical outcomes. Therefore, developing novel biomarkers and therapeutic targets for chemoresistant GBM is crucial for long-term cures. METHODS: Transcriptomic profiles of glioblastoma were downloaded from gene expression omnibus (GEO) and TCGA database. Differentially expressed genes were analyzed and candidate gene PLK2 was selected for subsequent validation. Clinical samples and corresponding data were collected from our center and measured using immunohistochemistry analysis. Lentiviral transduction and in vivo xenograft transplantation were used to validate the bioinformatic findings. GSEA analyses were conducted to identify potential signaling pathways related to PLK2 expression and further confirmed by in vitro mechanistic assays. RESULTS: In this study, we identified PLK2 as an extremely suppressed kinase-encoding gene in GBM samples, particularly in therapy resistant GBM. Additionally, reduced PLK2 expression implied poor prognosis and TMZ resistance in GBM patients. Functionally, up-regulated PLK2 attenuated cell proliferation, migration, invasion, and tumorigenesis of GBM cells. Besides, exogenous overexpression of PLK2 reduced acquired TMZ resistance of GBM cells. Furthermore, bioinformatics analysis indicated that PLK2 was negatively correlated with Notch signaling pathway in GBM. Mechanically, loss of PLK2 activated Notch pathway through negative transcriptional regulation of HES1 and degradation of Notch1. CONCLUSION: Loss of PLK2 enhances aggressive biological behavior of GBM through activation of Notch signaling, indicating that PLK2 could be a prognostic biomarker and potential therapeutic target for chemoresistant GBM.

Elevation of CXCL1 indicates poor prognosis and radioresistance by inducing mesenchymal transition in glioblastoma.

INTRODUCTION: Glioblastoma (GBM) is identified as a lethal malignant tumor derived from the nervous system. Despite the standard clinical strategy including maximum surgical resection, temozolomide (TMZ) chemotherapy, and radiotherapy, the median survival of GBM patients remains <15 months. Accumulating evidence indicates that rapid-acquired radioresistance is one of the most common reasons for GBM recurrence. Therefore, developing novel therapeutic targets for radioresistant GBM could yield long-term cures. AIMS: To investigate the functional role of CXCL1 in the acquired radioresistance and identify the molecular pathway correlated to CXCL1. RESULTS: In this study, we identified that CXCL1 is highly expressed in GBM and the elevation of CXCL1 is involved in radioresistance and poor prognosis in GBM patients. Additionally, silencing CXCL1 attenuated the proliferation and radioresistance of GBM cells. Furthermore, we demonstrated that CXCL1-overexpression induced radioresistance through mesenchymal transition of GBM via the activation of nuclear factor-kappa B (NF-κB) signaling. CONCLUSION: CXCL1 was highly enriched in GBM and positively correlated with poor prognosis in GBM patients. Additionally, elevated CXCL1 induced radioresistance in GBM through regulation of NF-κB signaling by promoting mesenchymal transition in GBM.

Targeting Aurora kinase B attenuates chemoresistance in glioblastoma via a synergistic manner with temozolomide.

BACKGROUND: Recent studies have demonstrated that aberrant expression or activation of kinases results in oncogenesis of a wide range of cancers including GBM. Inhibition of kinases expression induces a reduction of therapy resistance. In this study, we investigate the underlying mechanism by which glioblastoma (GBM) cells acquire resistance to Temozolomide (TMZ) through Aurora kinase B (AURKB) thus to identify novel therapeutic targets and prognostic biomarkers for GBM. METHODS: AURKB was identified as a key candidate kinase-encoding gene in chemoresistance regulation by using kinome-wide bioinformatic analysis. Afterwards, the potential biological functions of AURKB in oncogenesis and chemoresistance were investigated by lentivirus-dependent silencing of AURKB combined with qRT-PCR, western blot and in vivo intra-cranial xenograft mice models. Additionally, immunohistochemistry (IHC) assays were performed to explore the clinical significance of AURKB in glioma patients. Lastly, Chou-Talalay method was used to confirm the synergistic effect of TMZ combined with AURKB inhibitor. RESULTS: AURKB was among the most significantly up-regulated kinase-coding genes in TMZ resistant GBM cells according to database GSE68029, moreover, an increased expression of AURKB was closely associated with poor prognosis in glioma and GBM patients. AURKB knock-down resensitized U87 resistant cells to TMZ both in vitro and in vivo. Additionally, the combination of TMZ and Hesperadin, a specific AURKB inhibitor, significantly suppressed the proliferation of TMZ resistant GBM cells thus dramatically prolonged the survival of xenograft mice viaa synergistic effect with TMZ. CONCLUSION: Elevated AURKB expression was strongly correlated to TMZ resistant acquisition and poor prognosis, furthermore, targeting AURKB would be a potential therapeutic target for GBM patients.

Combined elevation of AURKB and UBE2C predicts severe outcomes and therapy resistance in glioma.

OBJECTIVES: Aurora kinase B (AURKB) and Ubiquitin conjugating enzyme E2C (UBE2C) are involved in tumorigenesis of gliomas and other malignancies as well, but their clinicopathologic significance in gliomas is unknown and the prognostic value of combined expression of AURKB and UBE2C has not been explored. In this study, we investigate the correlation between glioma prognosis and combined expressions of AURKB and UBE2C thus to identify novel therapeutic targets and prognostic biomarkers for glioma patients. METHODS: AURKB was identified as one of the key candidate kinase-encoding genes in three different databases by using kinome-wide bioinformatic analysis. Afterwards, UBE2C was chosen as the most closely relevant genes to AURKB according to Spearman correlation test. Then the expressions of AURKB and UBE2C at either transcriptome or protein levels were measured by quantitative Real-time PCR (qRT-PCR) or immunohistochemistry (IHC), respectively. Additionally, Kaplan-Meier analyses were conducted using data from TCGA, Rembrandt and our clinical center to investigate the clinical significance of AURKB and UBE2C. Furthermore, receiver operating characteristic (ROC) analysis was performed to evaluate the sensitivity and specificity of AURKB and UBE2C in predicting the outcomes of glioma patients. Moreover, survival data of patients who underwent post-surgical chemo/radio treatment were extracted and the Kaplan-Meier analyses were performed to investigate the correlation between treatment resistance and combined expressions of AURKB and UBE2C. RESULTS: Both AURKB and UBE2C were significantly up-regulated in gliomas compared to normal brain tissues and the combined elevation of AURKB and UBE2C were strongly associated with histological classification in glioma. Moreover, overexpression of either AURKB or UBE2C strongly correlated to more severe overall survival. Notably, upregulation of these two genes revealed unfavorable outcomes (shorter overall survival and therapy resistance) in glioma patients with significant sensitivity and specificity. CONCLUSION: Simultaneously elevated expressions of AURKB and UBE2C was strongly correlated to poor prognosis and therapy resistance in glioma, furthermore, our data suggest for the first time that the combination of AURKB and UBE2C overexpression could be highly sensitive prognostic markers and potential therapeutic targets for glioma patients.