HOTAIR/miR-125 axis-mediated Hexokinase 2 expression promotes chemoresistance in human glioblastoma.

Drug resistance is one of the major obstacles in glioblastoma (GBM) treatments using temozolomide (TMZ) based conventional chemotherapy. Recent studies revealed that Hexokinase 2 (HK2)-mediated glycolysis is one of the sources, as the association of chemoresistance and the expression of HK2 was confirmed in multiple cancers. However, there has been little knowledge of the functional contribution of HK2 to TMZ resistance in GBM. In our study, we found that HK2 expression is crucial for GBM proliferation and chemoresistance. In contrast to the healthy brain, HK2 expression is much higher in human GBM, especially in those patients with GBM recurrence. High HK2 expression is negatively related to the overall survival in GBM patients. HK2 depletion in GBM cells suppressed the GBM cell proliferation and increased sensitivity to TMZ-induced apoptosis. Both HK2-mediated glycolysis and mitochondria permeability transition pore opening (MPTP) were associated with its function in chemoresistance. Furthermore, we also revealed that the abnormal expression of HK2 was modulated by the expression of HOTAIR, a long non-coding RNA (lncRNA). The absence of HOTAIR in GBM cells suppressed the HK2 expression in protein and mRNA level and, therefore, inhibited the cell proliferation and enhanced the cytotoxicity of TMZ both in vivo and in vitro. HOTAIR promoted the expression of HK2 by targeting mir-125, which suppressed the GBM cell proliferation and increased the TMZ-induced apoptosis. These findings shed light on a new therapeutic strategy in modulating HOTAIR/miR-125, which may interfere with the expression of HK2, and enhance the therapeutic sensitivity of GBM to TMZ.

Risk Factors of Transient Cortical Blindness After Cerebral Angiography: A Multicenter Study.

Background: Although transient cortical blindness is a rare complication following cerebral angiography, identification of risk factors for the development of transient cortical blindness after cerebral angiography is an important clinical issue. Material and methods: Between January 2008 and April 2018, 5,126 patients at five high-volume medical centers who underwent cerebral angiography procedures were enrolled in this multicenter cohort study. Patient baseline characteristics and surgery-related factors were analyzed. We used multivariate logistic regression to examine factors associated with transient cortical blindness. Results: Eighteen patients (0.35%) in the total cohort of 5,126 suffered transient cortical blindness. After univariate statistical analysis, no significant differences were determined between the transient cortical blindness group and the control group regarding gender (p = 0.454), age (p = 0.872), smoking (p = 0.170), diabetes (p = 0.800), and hypertension (p = 0.100). Compared with the control group, the transient cortical blindness group weighed less (p = 0.020), and had a larger dose of contrast agent (p = 0.034) and more instances of contrast agent injected into the posterior circulation (p < 0.001). Logistic regression analysis identified contrast agent dose and contrast agent injected into posterior circulation as independent predictive factors for transient cortical blindness (P < 0.05). Conclusion: Larger doses off contrast agent and contrast agent injected into the posterior circulation are potential independent predictive factors for transient cortical blindness following cerebral angiography.

Snail expression contributes to temozolomide resistance in glioblastoma.

Glioblastoma (GBM) is one of most malignancy tumors worldwide. Temozolomide (TMZ) is an important chemotherapy drug in GBM therapy. However, acquired TMZ-resistance frequently happens in GBM therapy and leads to high percentage of GBM recurrence. In our study, we demonstrated that Snail is upregulated in recurrent GBM tumors, and promotes the GBM cells resistant to TMZ induced apoptosis. Enhanced expression of Snail compromises the apoptosis induced by TMZ, and increases the cell migration and invasion. Reversely, depletion of Snail by siRNA has the opposite effects. In addition, we confirmed that the expression of Snail is modulated by STAT3 activation, since phospho-STAT3 level is relatively higher in recurrent GBM tumors and TMZ resistant cells. Knockdown of STAT3 turns down the expression of Snail in protein and mRNA level, and thereby sensitized the resistant GBM cells to TMZ treatment. Interestingly, the activation of STAT3 in GBM resistant cells is modulated by IL-6 secretion. Suppression of IL-6 abandons the STAT3 activation, and reduces its binding with Snail promoter. Inhibition of IL-6 by its antibody enhanced the killing effects of TMZ both in vivo and in vitro. Overall, our results provided a rational to overcome the TMZ resistant in GBM treatment by targeting IL-6-STAT3-Snail pathway.

Dual PI3K/mTOR Inhibitor, XL765, suppresses glioblastoma growth by inducing ER stress-dependent apoptosis.

Background: Deregulated phosphoinositide 3-kinase (PI3K)/mTOR signaling commonly exists in glioblastoma (GBM), making this axis an attractive target for therapeutic manipulation. A recent dual inhibitor of PI3K/mTOR pathway, XL765, exhibited an attractive suppression effect on GBM tumor growth. However, the exact functional mechanisms of tumor suppression mediated by XL765 have not yet been fully characterized. Purpose: In this study, we took efforts to assess the effects of PI3K/mTOR blockade by XL765 on GBM growth in vitro and in vivo. Methods: We analyzed the cytotoxicity of XL765 in three different GBM cell lines, A172, U87MG, and T98G, by using Hoechst 33258 (Invitrogen), Annexin V/propidium iodide (PI), as well as Cell Counting Kit -8 (CCK-8) assay. We also used A172 xenograft model to study the effect of XL765 in vivo. Results: We found that XL765 inhibits GBM viability with a wide range of potencies. Importantly, XL765 suppressed GBM cell growth by inducing endoplasmic reticulum (ER) stress dependent apoptosis. The activation of CHOP/DR5 pathway by XL765 induced ER stress is responsible for the induction of apoptosis. Moreover, the inhibition of mTOR signal by XL765 is the major source of ER stress, rather than inhibition of PI3K. At last, we demonstrated that combination of XL765 with GMB chemotherapeutic drug, temozolomide (TMZ), can achieved better therapy effect in vitro and in vivo. Conclusion: Overall, our data show that targeting PI3K/mTOR by XL765 is a promising therapeutic strategy to relieve tumor burden in GBM patients.

Inhibition of cyclin E1 overcomes temozolomide resistance in glioblastoma by Mcl-1 degradation.

Glioblastoma (GBM) is one of the major causes of brain cancer-related mortality worldwide. Temozolomide (TMZ) is an important agent against GBM. Acquired TMZ-resistance severely limits the chemotherapeutic effect and leads to poor GBM patient survival. To study the underlying mechanism of drug resistance, two TMZ resistant GBM cell lines, A172 and U87, were generated. In this study, the TMZ resistant cells have less apoptosis and cell-cycle change in response to the TMZ treatment. Western blot results revealed that cyclin E1 was upregulation in TMZ resistant cells. Inhibition or depletion of cyclin E1 re-sensitized the resistant cells to the TMZ treatment, which indicated the induction of cyclin E1 is the cause of TMZ resistance in GBM cells. Furthermore, we also found the expression of cyclin E1 stabilized the expression of Mcl-1, which contributes to the TMZ resistance in GBM cells. Finally, our in vivo xenograft data showed that the combination of flavopiridol, a cyclin E1/CDK2 inhibitor, overcomes the TMZ resistant by inducing higher apoptosis. Overall, our data provided a rationale to overcome the TMZ resistant in GBM treatment by inhibiting the cyclin E1 activity.

Increased invasive phenotype of CSF-1R expression in glioma cells via the ERK1/2 signaling pathway.

Glioma is a common malignant tumor of the central nervous system (CNS) that has no effective treatment. In this study, we report that colony-stimulating factor-1 receptor (CSF-1R) is a key mediator of malignant features in glioma via modulation of the activity of extracellular signal-regulated kinase 1/2 (ERK1/2) signaling. In general, CSF-1R upregulation in glioma is associated with poor histologic grade and sursvival. Enforced expression of CSF-1R is sufficient to enhance cell growth, migration, invasion, and epithelial-mesenchymal transition, while CSF-1R silencing suppresses the above-described malignant phenotypes. Mechanistic investigations show that CSF-1R promotes activation of the ERK1/2 signaling pathway. Inhibition of the ERK1/2 pathway by SCH772984 reduces CSF-1R-induced migration, invasion, and lung metastasis of glioma cells, thus establishing a role of the ERK1/2 signaling pathway in mediating the CSF-1R effect. In summary, our results suggest that CSF-1R overexpression in gliomas contributes to the malignant behaviors of cancer cells.

RETRACTED: Neferine inhibits proliferation, migration and invasion of U251 glioma cells by down-regulation of miR-10b.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. Panels from Figures 2A, 2C and 5D appear similar to the "Migrated cell" panels from Figure 2E and the panels "Migrated cell/mimic NC + pEX" and "Invasive cell/miR-122 mimic + pEX" from Figure 7D of the article that was previously published by Daliang Kong and Yang Wang in the Journal of Cellular Biochemistry 119 (2018) 1050-1061 https://doi.org/10.1002/jcb.26273. Also, panels from Figures 2A and 2C appear similar to the panels "sh-FOXM1" from Figure 5D and "sh-HULC" from Figure 2E of the article that was published by Qiu Hong Rui, Jian Bo Ma, Yu Feng Liao, Jin Hua Dai and Zhen Yu Cai in the Brazilian Journal of Medical and Biological Research 52(4) (2019) e7728 https://doi.org/10.1590/1414-431X20197728. Although this article was published earlier than the article from the Brazilian Journal of Medical and Biological Research, the Editor decided to retract this article given concerns about the reliability of the data.

Delta-6-desaturase inhibitor enhances radiation therapy in glioblastoma in vitro and in vivo.

BACKGROUND: It has been reported that cell inflammation pathways contribute to the development of prostaglandin E2 (PGE2)-inhibitor of DNA-binding protein-1 (ID1)-dependent radio-resistance in glioblastoma. Here, we proposed that inhibiting delta-6-desaturase (D6D) could block arachidonic acid synthesis and PGE2 production, thereby reversing PGE2-ID1-dependent radioresistance in glioblastoma cells and xenograft tumor models. MATERIALS AND METHODS: Two glioblastoma cell lines, namely, U-87 MG and LN-229, were used for the in vitro study. The combination effects of SC-26196 (a D6D inhibitor) and radiation were assessed by the MTS assay, colony formation assay, and cell apoptosis analysis. HPLC/MS analysis was performed to quantify the production of arachidonic acid and PGE2. For the in vivo study, 6-week-old nude mice, each bearing a U-87 MG xenograft tumor, were subjected to 4-week treatments of vehicle, SC-26196, radiation, or the combination of both. Tumor growth was monitored during the treatment, and the tumor tissues were collected at the end for further analysis. RESULTS: Treatment with SC-26196 significantly improved radiosensitivity in both glioblastoma cell lines in vitro, and radiosensitivity was associated with inhibited synthesis of arachidonic acid and PGE2. The combination of SC-26196 and radiation synergistically inhibited U-87 MG xenograft tumor growth, in association with the induction of tumor apoptosis and suppressed tumor proliferation. SC-26196 also inhibited arachidonic acid and PGE2 production in vivo and limited expression of ID1. CONCLUSION: These data suggested that the D6D inhibitor could reverse PGE2-ID1-dependent radioresistance in glioblastoma cells and xenograft tumor models by blocking the synthesis of arachidonic acid and PGE2. Although further investigation is required, the outcomes from this study may guide us in developing a potentially novel combination strategy for current glioblastoma therapy.

MicroRNA-598 Inhibits Cell Proliferation and Invasion of Glioblastoma by Directly Targeting Metastasis Associated in Colon Cancer-1 (MACC1).

The dysregulation of microRNA (miRNA) expression is closely related with tumorigenesis and tumor development in glioblastoma (GBM). In this study, we found that miRNA-598 (miR-598) expression was significantly downregulated in GBM tissues and cell lines. Restoring miR-598 expression inhibited cell proliferation and invasion in GBM. Moreover, we validated that metastasis associated in colon cancer-1 (MACC1) is a novel target of miR-598 in GBM. Restoring MACC1 expression reversed the inhibitory effects of miR-598 overexpression on GBM cells. In addition, miR-598 overexpression suppressed Met/AKT pathway activation in GBM. Our results provided compelling evidence that miR-598 serves tumor-suppressive roles in GBM and that its antioncogenic effects are mediated chiefly through the direct suppression of MACC1 expression and regulation of the Met/AKT signaling pathway. Therefore, miR-598 is a potential target in the treatment of GBM.

Polysaccharide sulphated derivative from Aconitum coreanum induces cell apoptosis in the human brain glioblastoma U87MG cell line via the NF-κB/Bcl-2 cell apoptotic signaling pathway.

In a previous study, our team preliminarily investigated the bioefficacy of an extracted polysaccharide from the medicinal plant Aconitum coreanum (ACP1). In the present study, we further evaluated the antitumor efficacy of an ACP1 sulphated derivative (ACP1­s) in the human brain glioblastoma U87MG cell line. Cell viability assay and flow cytometry results demonstrated that 400, 800 and 1,600 µg/ml ACP1­s induced cell growth inhibition and cell apoptosis. We then investigated the underlying molecular mechanism of the ACP1­s induced cell apoptosis and found that the NF­κB/Bcl­2 cell apoptotic signaling pathway was involved. Following treatment with ACP1­s, the expression of IκB in U87MG cells was significantly upregulated, whereas the level of NF­κB and the ratio of Bcl­2/Bax was significantly decreased. The level of cleaved caspase­3 was increased accordingly. When we introduced exogenous p65 protein into the U87MG cells, the ACP1­s-induced cell growth inhibition and cell apoptosis were partially neutralized, and the expression of the anti­apoptotic gene Bcl­2 was recovered accordingly. These findings suggest the potential value of ACP1­s as a novel therapeutic agent for the treatment of glioblastoma.

Intraoperative neurophysiological monitoring to protect the facial nerve during microsurgery for large vestibular schwannomas.

OBJECTIVE: Microsurgery is the preferred treatment for large vestibular schwannomas (VSs). However, anatomical and functional preservation of the facial nerve (FN) remains a challenge during this surgery. The aim of this study was to determine whether it is beneficial to the preservation rates of the FN during microsurgical treatment of large VSs using intraoperative neurophysiological monitoring (IONM). METHODS: We retrospectively reviewed 53 patients with large VSs that underwent microsurgical resection via the retrosigmoid approach in our department during April 2009 to March 2016. IONM was used in 29 cases. Postoperative FN function was evaluated using the House-Brankmann (HB) FN grading scale at 2 weeks and 3 and 6 months after surgery. RESULTS: There were two cases (8.3%) of subtotal resection in the monitored group, compared with one case (3.4%) among the controls (p>0.05). The anatomical integrity rate for FNs was 100% in the monitored group, which was significantly different from 83.3% in the controls (p<0.05), which included four cases the FN was injured, mostly around the internal auditory foramen. Functional preservation of the FN in the monitored group differed significantly from that in the controls at 2 weeks and 3 and 6 months postoperatively (p<0.05). CONCLUSIONS: IONM contributes to FN anatomical integrity and functional preservation rates during microsurgery of large VSs. It has no significant effect on differences in the total VS resection rates.

Thiabendazole, a well-known antifungal drug, exhibits anti-metastatic melanoma B16F10 activity via inhibiting VEGF expression and inducing apoptosis.

Thiabendazole, an orally available antifungal drug, has been used in clinical practice for 40 years. Previous studies indicated its potential in inhibiting angiogenesis in both animal models and in human cells. Malignant melanoma is associated with angiogenesis and it is unknown whether thiabendazole is effective for malignant melanoma or not. In our research, the effects of thiabendazole on the proliferation of the murine metastatic melanoma cell line B16F10 in vitro and in vivo and the molecular mechanism were investigated. Assay of cell viability, chick embryo chorioallantoic membrane assay, quantitative real-time PCR, Western blot, wound healing assay, annexin V/propidium iodide (AV/PI) assay and B16F10-xenograft model were applied to elucidate the mechanism of thiabendazole on B16F10 cells. Thiabendazole inhibited B16F10 proliferation in vitro in a dose- and time-dependent manner with an IC50 of 532.4 +/- 32.6, 322.9 +/- 28.9, 238.5 +/- 19.8 microM at 24, 48, and 72 h, respectively. Moreover, thiabendazole inhibited the angiogenesis and the migration of B16F10 cells in vitro. Furthermore, thiabendazole restrained transcription and translation of the VEGF gene in B16F10 in vitro, and the apoptotic percentage of B16F10 cells was increased after exposure to thiabendazole. Finally, in the B16F10-bearing mice model, thiabendazole significantly suppressed tumor growth with inhibitory rates of 16.5%, 35.4% and 48.7% at the treatment of thiabendazole 20, 40 and 80 mg/kg, respectively. These results further indicated that thiabendazole may be a potential candidate for the treatment of malignant melanoma.