Urinary D-asparagine level is decreased by the presence of glioblastoma.

Gliomas, particularly glioblastomas (GBMs), pose significant challenges due to their aggressiveness and poor prognosis. Early detection through biomarkers is critical for improving outcomes. This study aimed to identify novel biomarkers for gliomas, particularly GBMs, using chiral amino acid profiling. We used chiral amino acid analysis to measure amino acid L- and D-isomer levels in resected tissues (tumor and non-tumor), blood, and urine from 33 patients with primary gliomas and 24 healthy volunteers. The levels of D-amino acid oxidase (DAO), a D-amino acid-degrading enzyme, were evaluated to investigate the D-amino acid metabolism in brain tissue. The GBM mouse model was created by transplanting GBM cells into the brain to confirm whether gliomas affect blood and urine chiral amino acid profiles. We also assessed whether D-amino acids produced by GBM cells are involved in cell proliferation. D-asparagine (D-Asn) levels were higher and DAO expression was lower in glioma than in non-glioma tissues. Blood and urinary D-Asn levels were lower in patients with GBM than in healthy volunteers (p < 0.001), increasing after GBM removal (p < 0.05). Urinary D-Asn levels differentiated between healthy volunteers and patients with GBM (area under the curve: 0.93, sensitivity: 0.88, specificity: 0.92). GBM mouse model validated the decrease of urinary D-Asn in GBM. GBM cells used D-Asn for cell proliferation. Gliomas induce alterations in chiral amino acid profiles, affecting blood and urine levels. Urinary D-Asn emerges as a promising diagnostic biomarker for gliomas, reflecting tumor presence and severity.

Recurrence of an extracranial internal carotid artery aneurysm treated with STA-MCA bypass and trapping due to neovascularization from an ascending pharyngeal artery: illustrative case.

BACKGROUND: Extracranial internal carotid artery aneurysms (EICAs) are rare. Although a high mortality risk has been reported in nonoperated cases, the optimal treatment for EICAs remains unknown. OBSERVATIONS: A 79-year-old female presented with painless swelling in the right neck. Imaging revealed a giant EICA with a maximum diameter of 3.2 cm. Superficial temporal artery-middle cerebral artery bypass and internal carotid artery (ICA) trapping were performed. Because the distal aneurysm edge was at the C1 level, the distal portion of the aneurysm was occluded by endovascular coiling, and the proximal portion was surgically ligated. Blood flow into the aneurysm disappeared after the operation. Three years postsurgery, enlargement of the aneurysm with blood flow from the ascending pharyngeal artery (APA) was detected. The EICA was resected after coiling the APA and ligating both ends of the aneurysm. Pathologically, neovascularization within the aneurysm wall was observed. LESSONS: Even if blood flow into an EICA disappears after ICA trapping, the EICAs can enlarge due to neovascularization from the neighboring artery. From the outset, removal of the aneurysm should be considered as a radical treatment strategy for giant EICAs.

Nuclear transport surveillance of p53 by nuclear pores in glioblastoma.

Nuclear pore complexes (NPCs) are the central apparatus of nucleocytoplasmic transport. Disease-specific alterations of NPCs contribute to the pathogenesis of many cancers; however, the roles of NPCs in glioblastoma (GBM) are unknown. In this study, we report genomic amplification of NUP107, a component of NPCs, in GBM and show that NUP107 is overexpressed simultaneously with MDM2, a critical E3 ligase that mediates p53 degradation. Depletion of NUP107 inhibits the growth of GBM cell lines through p53 protein stabilization. Mechanistically, NPCs establish a p53 degradation platform via an export pathway coupled with 26S proteasome tethering. NUP107 is the keystone for NPC assembly; the loss of NUP107 affects the integrity of the NPC structure, and thus the proportion of 26S proteasome in the vicinity of nuclear pores significantly decreases. Together, our findings establish roles of NPCs in transport surveillance and provide insights into p53 inactivation in GBM.

α-SMA positive vascular mural cells suppress cyst formation in hemangioblastoma.

Approximately 60% of hemangioblastomas (HBs) have peritumoral cysts adjacent to the tumor, which can cause neurological deficits due to the mass effect, and the management of cyst formation is a clinical challenge. Vascular mural cells surrounding endothelial cells consist of vascular smooth muscle cells (vSMCs) and pericytes, which are essential elements that support blood vessels and regulate permeability. This study investigated the involvement of mural cells in cyst formation. We analyzed the expression of α-smooth muscle actin (α-SMA), platelet-derived growth factor receptor-beta (PDGFRB), and CD31 in 39 consecutive human cerebellar HBs, 20 of cystic and 19 of solid type. Solid type HBs showed stronger diffuse expression of α-SMA in precapillary arterioles and capillaries within the tumor than cystic type HBs (p = 0.001), whereas there was no difference in PDGFRB and CD31 expression. Detailed observation with immunofluorescence demonstrated that α-SMA was expressed in vascular mural cells surrounding capillaries in the solid rather than in the cystic type. Multivariate analysis including various clinical and pathological factors showed that lower α-SMA expression was significantly correlated with cyst formation (p < 0.001). Our data suggested that vascular mural cells from precapillary arterioles to capillaries expressing α-SMA may be pericytes and play a crucial role in HB cystogenesis.

Therapeutic potential of pentamidine for glioma-initiating cells and glioma cells through multimodal antitumor effects.

Glioma-initiating cells, which comprise a heterogeneous population of glioblastomas, contribute to resistance against aggressive chemoradiotherapy. Using drug reposition, we investigated a therapeutic drug for glioma-initiating cells. Drug screening was undertaken to select candidate agents that inhibit proliferation of two different glioma-initiating cells lines. The alteration of proliferation and stemness of the two glioma-initiating cell lines, and proliferation, migration, cell cycle, and survival of these two differentiated glioma-initiating cell lines and three different glioblastoma cell lines treated with the candidate agent were evaluated. We also used a xenograft glioma mouse model to evaluate anticancer effects of treated glioma cell lines. Among the 1301 agents, pentamidine-an antibiotic for Pneumocystis jirovecii-emerged as a successful antiglioma agent. Pentamidine treatment suppressed proliferation and stemness in glioma-initiating cell lines. Proliferation and migration were inhibited in all differentiated glioma-initiating cells and glioblastoma cell lines, with cell cycle arrest and caspase-dependent apoptosis induction. The in vivo study reproduced the same findings as the in vitro studies. Pentamidine showed a stronger antiproliferative effect on glioma-initiating cells than on differentiated cells. Western blot analysis revealed pentamidine inhibited phosphorylation of signal transducer and activator of transcription 3 in all cell lines, whereas Akt expression was suppressed in glioma-initiating cells but not in differentiated lines. In the present study, we identified pentamidine as a potential therapeutic drug for glioma. Pentamidine could be promising for the treatment of glioblastomas by targeting both glioma-initiating cells and differentiated cells through its multifaceted antiglioma effects.

Intra-Brain and Plasma Levels of L-Serine Are Associated with Cognitive Status in Patients with Chronic Kidney Disease.

Introduction: The number of patients with chronic kidney disease (CKD) is increasing worldwide. Cognitive impairment is one of the comorbidities of CKD. With the increased number of aged population, novel biomarkers of impaired cognitive function are required. Intra-body profile of amino acid (AA) is reportedly altered in patients with CKD. Although some AAs act as neurotransmitters in the brain, it is not clear whether altered AA profile are associated with cognitive function in patients with CKD. Therefore, intra-brain and plasma levels of AAs are evaluated with respect to cognitive function in patients with CKD. Methods: Plasma levels of AAs were compared between 14 patients with CKD, including 8 patients with diabetic kidney disease, and 12 healthy controls to identify the alteration of specific AAs in CKD. Then, these AAs were evaluated in the brains of 42 patients with brain tumor using non-tumor lesion of the resected brain. Cognitive function is analyzed with respect to intra-brain levels of AAs and kidney function. Moreover, plasma AAs were analyzed in 32 hemodialyzed patients with/without dementia. Results: In patients with CKD, plasma levels of asparagine (Asn), serine (Ser), alanine (Ala), and proline (Pro) were increased as compared to patients without CKD. Among these AAs, L-Ser, L-Ala, and D-Ser show higher levels than the other AAs in the brain. Intra-brain levels of L-Ser was correlated with cognitive function and kidney function. The number of D-amino acid oxidase or serine racemase-positive cells was not correlated with kidney function. Moreover, the plasma levels of L-Ser are also decreased in patients with declined cognitive function who are treated with chronic hemodialysis. Conclusion: The decreased levels of L-Ser are associated with impaired cognitive function in CKD patients. Especially, plasma L-Ser levels may have a potential for novel biomarker of impaired cognitive function in patients with hemodialysis.

COL1A2 inhibition suppresses glioblastoma cell proliferation and invasion.

OBJECTIVE: An extracellular matrix such as collagen is an essential component of the tumor microenvironment. Collagen alpha-2(I) chain (COL1A2) is a chain of type I collagen whose triple helix comprises two alpha-1 chains and one alpha-2 chain. The authors' proteomics data showed that COL1A2 is significantly higher in the blood of patients with glioblastoma (GBM) compared with healthy controls. COL1A2 has many different functions in various types of cancers. However, the functions of COL1A2 in GBM are poorly understood. In this study, the authors analyzed the functions of COL1A2 and its signaling pathways in GBM. METHODS: Surgical specimens and GBM cell lines (T98, U87, and U251) were used. The expression level of COL1A2 was examined using GBM tissues and normal brain tissues by quantitative real-time polymerase chain reaction. The clinical significance of these levels was evaluated using Kaplan-Meier analysis. Small interfering RNA (siRNA) and small hairpin RNA of COL1A2 were transfected into GBM cell lines to investigate the function of COL1A2 in vitro and in vivo. Flow cytometry was introduced to analyze the alteration of cell cycles. Western blot and immunohistochemistry were performed to analyze the underlying mechanisms. RESULTS: The expression level of COL1A2 was upregulated in GBM compared with normal brain tissues. A higher expression of COL1A2 was correlated with poor progression-free survival and overall survival. COL1A2 inhibition significantly suppressed cell proliferation in vitro and in vivo, likely due to G1 arrest. The invasion ability was notably deteriorated by inhibiting COL1A2. Cyclin D1, cyclin-dependent kinase 1, and cyclin-dependent kinase 4, which are involved in the cell cycle, were all downregulated after blockade of COL1A2 in vitro and in vivo. Phosphoinositide 3-kinase inhibitor reduced the expression of COL1A2. Although downregulation of COL1A2 decreased the protein kinase B (Akt) phosphorylation, Akt activator can phosphorylate Akt in siRNA-treated cells. This finding suggests that Akt phosphorylation is partially dependent on COL1A2. CONCLUSIONS: COL1A2 plays an important role in driving GBM progression. COL1A2 inhibition attenuated GBM proliferation by promoting cell cycle arrest, indicating that COL1A2 could be a promising therapeutic target for GBM treatment.

Non-occlusive mesenteric ischemia during bevacizumab treatment for glioblastoma: a case report.

Glioblastoma is one of the most aggressive brain tumors in adults. The standard treatment is radiotherapy and chemotherapy based on the Stupp regimen after maximal safe resection. One effective chemotherapeutic drug is bevacizumab, which can prolong progression-free survival in glioblastoma patients but not overall survival. Adverse events of bevacizumab include hypertension, proteinuria, delayed wound healing, bleeding of the nose and gums, and thromboembolism resulting in gastrointestinal perforation. Herein, we describe an autopsy case of a patient with glioblastoma who died from non-occlusive mesenteric ischemia that was presumably caused by bevacizumab.

Tumor Microenvironment in Glioma Invasion.

A major malignant trait of gliomas is their remarkable infiltration capacity. When glioma develops, the tumor cells have already reached the distant part. Therefore, complete removal of the glioma is impossible. Recently, research on the involvement of the tumor microenvironment in glioma invasion has advanced. Local hypoxia triggers cell migration as an environmental factor. The transcription factor hypoxia-inducible factor (HIF) -1α, produced in tumor cells under hypoxia, promotes the transcription of various invasion related molecules. The extracellular matrix surrounding tumors is degraded by proteases secreted by tumor cells and simultaneously replaced by an extracellular matrix that promotes infiltration. Astrocytes and microglia become tumor-associated astrocytes and glioma-associated macrophages/microglia, respectively, in relation to tumor cells. These cells also promote glioma invasion. Interactions between glioma cells actively promote infiltration of each other. Surgery, chemotherapy, and radiation therapy transform the microenvironment, allowing glioma cells to invade. These findings indicate that the tumor microenvironment may be a target for glioma invasion. On the other hand, because the living body actively promotes tumor infiltration in response to the tumor, it is necessary to reconsider whether the invasion itself is friend or foe to the brain.

SMURF2 phosphorylation at Thr249 modifies glioma stemness and tumorigenicity by regulating TGF-ß receptor stability.

Glioma stem cells (GSCs) contribute to the pathogenesis of glioblastoma, the most malignant form of glioma. The implication and underlying mechanisms of SMAD specific E3 ubiquitin protein ligase 2 (SMURF2) on the GSC phenotypes remain unknown. We previously demonstrated that SMURF2 phosphorylation at Thr249 (SMURF2Thr249) activates its E3 ubiquitin ligase activity. Here, we demonstrate that SMURF2Thr249 phosphorylation plays an essential role in maintaining GSC stemness and tumorigenicity. SMURF2 silencing augmented the self-renewal potential and tumorigenicity of patient-derived GSCs. The SMURF2Thr249 phosphorylation level was low in human glioblastoma pathology specimens. Introduction of the SMURF2T249A mutant resulted in increased stemness and tumorigenicity of GSCs, recapitulating the SMURF2 silencing. Moreover, the inactivation of SMURF2Thr249 phosphorylation increases TGF-ß receptor (TGFBR) protein stability. Indeed, TGFBR1 knockdown markedly counteracted the GSC phenotypes by SMURF2T249A mutant. These findings highlight the importance of SMURF2Thr249 phosphorylation in maintaining GSC phenotypes, thereby demonstrating a potential target for GSC-directed therapy.

Nucleoporin TPR (translocated promoter region, nuclear basket protein) upregulation alters MTOR-HSF1 trails and suppresses autophagy induction in ependymoma.

Children with ependymoma have high mortality rates because ependymoma is resistant to conventional therapy. Genomic and transcriptomic studies have identified potential targets as significantly altered genes in ependymoma patients. Although several candidate oncogenes in ependymoma were recently reported, the detailed mechanisms for the roles of these candidate oncogenes in ependymoma progression remain unclear. Here, we report an oncogenic role of the nucleoporin TPR (translocated promoter region, nuclear basket protein) in regulating HSF1 (heat shock transcription factor 1) mRNA trafficking, maintaining MTORC1 activity to phosphorylate ULK1, and preventing macroautophagy/autophagy induction in ependymoma. High expression of TPR were associated with increased HSF1 and HSPA/HSP70 expression in ependymoma patients. In an ependymoma mouse xenograft model, MTOR inhibition by rapamycin therapeutically suppressed TPR expression and reduced tumor size in vivo. Together, these results suggest that TPR may act as a biomarker for ependymoma, and pharmacological interventions targeting TPR-HSF1-MTOR may have therapeutic potential for ependymoma treatment.Abbreviations: ATG: autophagy related; BECN1: beclin 1; BSA: bovine serum albumin; CQ: chloroquine; DMSO: dimethyl sulfoxide; GEO: gene expression omnibus; GFP: green fluorescence protein; HSF1: heat shock transcription factor 1; HSPA/HSP70: heat shock protein family A (Hsp70); LMNB1: lamin B1; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MAPK: mitogen-activated protein kinase; MAPK8/JNK: mitogen-activated protein kinase 8; MTORC1: mechanistic target of rapamycin kinase complex 1; NPC: nuclear pore complex; NUP: nucleoporin; PBS: phosphate-buffered saline; q-PCR: quantitative real time PCR; SDS: sodium dodecyl sulfate; SQSTM1: sequestosome 1; STED: stimulated emission depletion microscopy; STX17: syntaxin 17; TCGA: the cancer genome atlas; TPR: translocated promoter region, nuclear basket protein; ULK1: unc-51 like autophagy activating kinase 1.

Ependymoma with C11orf95-MAML2 fusion: presenting with granular cell and ganglion cell features.

C11orf95-RELA fusion or, less frequently, YAP1 fusion is recurrently detected in most cases of supratentorial ependymoma. Other fusions have rarely been reported in some cases of supratentorial ependymoma, and little is known about their pathological or clinical features. Here, we present a case of supratentorial ependymoma with unusual pathological findings and C11orf95-MAML2 fusion. A 23-year-old man was admitted to our hospital because of headache and vomiting. Magnetic resonance imaging revealed a cystic lesion in the right frontal lobe, and gross total resection of the tumor was performed. Pathologically, the tumor was mainly composed of typical ependymal lesions with perivascular pseudorosettes and contained some atypical lesions, with granular and ganglion cell features. The tumor was diagnosed as anaplastic ependymoma, which was classified as grade III on the World Health Organization scale, and found to be RELA fusion-positive in the DNA methylation analysis. However, the tumor was negative for C11orf95-RELA fusion, and RNA sequencing detected C11orf95-MAML2 fusion. The patient has not received adjuvant therapy and has remained alive without any evidence of disease for 30 months, suggesting that the prognosis might be better than that of typical C11orf95-RELA fusion-positive ependymoma.

RBPJ contributes to the malignancy of glioblastoma and induction of proneural-mesenchymal transition via IL-6-STAT3 pathway.

Notch signaling plays a pivotal role in many cancers, including glioblastoma (GBM). Recombination signal binding protein for immunoglobulin kappa J region (RBPJ) is a key transcription factor of the Notch signaling pathway. Here, we interrogated the function of RBPJ in GBM. Firstly, RBPJ expression of GBM samples was examined. Then, we knocked down RBPJ expression in 2 GBM cell lines (U251 and T98) and 4 glioblastoma (GBM) stem-like cell lines derived from surgical samples of GBM (KGS01, KGS07, KGS10 and KGS15) to investigate the effect on cell proliferation, invasion, stemness, and tumor formation ability. Expression of possible downstream targets of RBPJ was also assessed. RBPJ was overexpressed in the GBM samples, downregulation of RBPJ reduced cell proliferation and the invasion ability of U251 and T98 cells and cell proliferation ability and stemness of glioblastoma stem-like cells (GSC) lines. These were accompanied by reduced IL-6 expression, reduced activation of STAT3, and inhibited proneural-mesenchymal transition (PMT). Tumor formation and PMT were also impaired by RBPJ knockdown in vivo. In conclusion, RBPJ promotes cell proliferation, invasion, stemness, and tumor initiation ability in GBM cells through enhanced activation of IL-6-STAT3 pathway and PMT, inhibition of RBPJ may constitute a prospective treatment for GBM.

Potential therapeutic effect of targeting glycogen synthase kinase 3ß in esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC) is a common gastrointestinal cancer and is often refractory to current therapies. Development of efficient therapeutic strategies against ESCC presents a major challenge. Glycogen synthase kinase (GSK)3ß has emerged as a multipotent therapeutic target in various diseases including cancer. Here we investigated the biology and pathological role of GSK3ß in ESCC and explored the therapeutic effects of its inhibition. The expression of GSK3ß and tyrosine (Y)216 phosphorylation-dependent activity was higher in human ESCC cell lines and primary tumors than untransformed esophageal squamous TYNEK-3 cells from an ESCC patient and tumor-adjacent normal esophageal mucosa. GSK3ß-specific inhibitors and small interfering (si)RNA-mediated knockdown of GSK3ß attenuated tumor cell survival and proliferation, while inducing apoptosis in ESCC cells and their xenograft tumors in mice. GSK3ß inhibition spared TYNEK-3 cells and the vital organs of mice. The therapeutic effect of GSK3ß inhibition in tumor cells was associated with G0/G1- and G2/M-phase cell cycle arrest, decreased expression of cyclin D1 and cyclin-dependent kinase (CDK)4 and increased expression of cyclin B1. These results suggest the tumor-promoting role of GSK3ß is via cyclin D1/CDK4-mediated cell cycle progression. Consequently, our study provides a biological rationale for GSK3ß as a potential therapeutic target in ESCC.

Leukemia-Associated Rho Guanine Nucleotide Exchange Factor and Ras Homolog Family Member C Play a Role in Glioblastoma Cell Invasion and Resistance.

Glioblastoma (GBM) is the most common primary malignant brain cancer in adults. A hallmark of GBM is aggressive invasion of tumor cells into the surrounding normal brain. Both the current standard of care and targeted therapies have largely failed to specifically address this issue. Therefore, identifying key regulators of GBM cell migration and invasion is important. The leukemia-associated Rho guanine nucleotide exchange factor (LARG) has previously been implicated in cell invasion in other tumor types; however, its role in GBM pathobiology remains undefined. Herein, we report that the expression levels of LARG and ras homolog family members C (RhoC), and A (RhoA) increase with glial tumor grade and are highest in GBM. LARG and RhoC protein expression is more prominent in invading cells, whereas RhoA expression is largely restricted to cells in the tumor core. Knockdown of LARG by siRNA inhibits GBM cell migration in vitro and invasion ex vivo in organotypic brain slices. Moreover, siRNA-mediated silencing of RhoC suppresses GBM cell migration in vitro and invasion ex vivo, whereas depletion of RhoA enhances GBM cell migration and invasion, supporting a role for LARG and RhoC in GBM cell migration and invasion. Depletion of LARG increases the sensitivity of GBM cells to temozolomide treatment. Collectively, these results suggest that LARG and RhoC may represent unappreciated targets to inhibit glioma invasion.

Glioma-derived extracellular vesicles promote tumor progression by conveying WT1.

Glioma persists as one of the most aggressive primary tumors of the central nervous system. Glioma cells are known to communicate with tumor-associated macrophages/microglia via various cytokines to establish the tumor microenvironment. However, how extracellular vesicles (EVs), emerging regulators of cell-cell communication networks, function in this process is still elusive. We report here that glioma-derived EVs promote tumor progression by affecting microglial gene expression in an intracranial implantation glioma model mouse. The gene expression of thrombospondin-1 (Thbs1), a negative regulator of angiogenesis, was commonly downregulated in microglia after the addition of EVs isolated from different glioma cell lines, which endogenously expressed Wilms tumor-1 (WT1). Conversely, WT1-deficiency in the glioma-derived EVs significantly attenuated the Thbs1 downregulation and suppressed the tumor progression. WT1 was highly expressed in EVs obtained from the cerebrospinal fluid of human patients with malignant glioma. Our findings establish a novel model of tumor progression via EV-mediated WT1-Thbs1 intercellular regulatory pathway, which may be a future diagnostic or therapeutic target.

Superficial Siderosis Associated with Long-Term Recurrence of Pilocytic Astrocytoma in an Elderly Person.

BACKGROUND: Superficial siderosis is an irreversible disease in the central nervous system caused by the deposition of hemosiderin in the subpial tissue due to persistent bleeding in the subarachnoid space. The main symptoms include sensorineural hearing loss, cerebellar ataxia, and pyramidal tract disorder. Superficial siderosis is mainly idiopathic, but bleeding factors such as tumors or history of surgery often play an important role in its pathogenesis. CASE DESCRIPTION: A 66-year-old man with a history of surgery for a cerebellar tumor 37 years ago complained of hearing loss. Magnetic resonance imaging showed recurrence of the tumor on T2-weighted images and hypointense areas along the cerebellar sulci on T2∗-weighted images. During the operation, microscopic bleeding was observed on the surface of the tumor. The pathologic diagnosis was pilocytic astrocytoma. A biopsy obtained during the first surgery revealed almost the same pathologic findings as those from a biopsy obtained during the second surgery, but the first specimen showed no hemosiderin deposition or active bleeding, which the second specimen did show. CONCLUSIONS: Recurrent pilocytic astrocytoma with intratumoral hemorrhage was the suspected cause for superficial siderosis. The source of chronic bleeding was identified with intraoperative and pathologic findings. We describe the first report of superficial siderosis associated with a pilocytic astrocytoma that recurred 37 years after an initial tumor was excised.

Gelsolin inhibits malignant phenotype of glioblastoma and is regulated by miR-654-5p and miR-450b-5p.

We have previously shown that gelsolin (GSN) levels are significantly lower in the blood of patients with glioblastoma (GBM) than in healthy controls. Here, we analyzed the function of GSN in GBM and examined its clinical significance. Furthermore, microRNAs involved in GSN expression were also identified. The expression of GSN was determined using western blot analysis and found to be significantly lower in GBM samples than normal ones. Gelsolin was mainly localized in normal astrocytes, shown using immunohistochemistry and immunofluorescence. Higher expression of GSN was correlated with more prolonged progression-free survival and overall survival. Gelsolin knockdown using siRNA and shRNA markedly accelerated cell proliferation and invasion in GBM in vitro and in vivo. The inactive form of glycogen synthase kinase-3ß was dephosphorylated by GSN knockdown. In GBM tissues, the expression of GSN and microRNA (miR)-654-5p and miR-450b-5p showed an inverse correlation. The miR-654-5p and miR-450b-5p inhibitors enhanced GSN expression, resulting in reduced proliferation and invasion. In conclusion, GSN, which inhibits cell proliferation and invasion, is suppressed by miR-654-5p and miR-450b-5p in GBM, suggesting that these miRNAs can be targets for treating GBM.

Identification of 2-Fluoropalmitic Acid as a Potential Therapeutic Agent Against Glioblastoma.

BACKGROUND: Glioblastomas (GBMs) are aggressive malignant brain tumors. Although chemotherapy with temozolomide (TMZ) can extend patient survival, most patients eventually demonstrate resistance. Therefore, novel therapeutic agents that overcome TMZ chemoresistance are required to improve patient outcomes. PURPOSE: Drug screening is an efficient method to find new therapeutic agents from existing drugs. In this study, we explored a novel anti-glioma agent by drug screening and analyzed its function with respect to GBM treatment for future clinical applications. METHODS: Drug libraries containing 1,301 diverse chemical compounds were screened against two glioma stem cell (GSC) lines for drug candidate selection. The effect of selected agents on GSCs and glioma was estimated through viability, proliferation, sphere formation, and invasion assays. Combination therapy was performed to assess its ability to enhance TMZ cytotoxicity against GBM. To clarify the mechanism of action, we performed methylation-specific polymerase chain reaction, gelatin zymography, and western blot analysis. RESULTS: The acyl-CoA synthetase inhibitor 2-fluoropalmitic acid (2-FPA) was selected as a candidate anti-glioma agent. 2-FPA suppressed the viability and stem-like phenotype of GSCs. It also inhibited proliferation and invasion of glioma cell lines. Combination therapy of 2-FPA with TMZ synergistically enhanced the efficacy of TMZ. 2-FPA suppressed the expression of phosphor-ERK, CD133, and SOX-2; reduced MMP-2 activity; and increased methylation of the MGMT promoter. CONCLUSION: 2-FPA was identified as a potential therapeutic agent against GBM. To extend these findings, physiological studies are required to examine the efficacy of 2-FPA against GBM in vivo.

Identification of GSK3ß inhibitor kenpaullone as a temozolomide enhancer against glioblastoma.

Cancer stem cells are associated with chemoresistance and rapid recurrence of malignant tumors, including glioblastoma (GBM). Although temozolomide (TMZ) is the most effective drug treatment for GBM, GBM cells acquire resistance and become refractory to TMZ during treatment. Therefore, glioma stem cell (GSC)-targeted therapy and TMZ-enhancing therapy may be effective approaches to improve GBM prognosis. Many drugs that suppress the signaling pathways that maintain GSC or enhance the effects of TMZ have been reported. However, there are no established therapies beyond TMZ treatment currently in use. In this study, we screened drug libraries composed of 1,301 existing drugs using cell viability assays to evaluate effects on GSCs, which led to selection of kenpaullone, a kinase inhibitor, as a TMZ enhancer targeting GSCs. Kenpaullone efficiently suppressed activity of glycogen synthase kinase (GSK) 3ß. Combination therapy with kenpaullone and TMZ suppressed stem cell phenotype and viability of both GSCs and glioma cell lines. Combination therapy in mouse models significantly prolonged survival time compared with TMZ monotherapy. Taken together, kenpaullone is a promising drug for treatment of GBM by targeting GSCs and overcoming chemoresistance to TMZ.