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OBJECTIVEEndothelial colony-forming cells (ECFCs) isolated from pediatric patients with moyamoya disease (MMD) have demonstrated decreased numbers and defective functioning in in vitro experiments. However, the function of ECFCs has not been evaluated using in vivo animal models. In this study, the authors compared normal and MMD ECFCs using a chronic cerebral hypoperfusion (CCH) rat model.METHODSA CCH rat model was made via ligation of the bilateral common carotid arteries (2-vessel occlusion [2-VO]). The rats were divided into three experimental groups: vehicle-treated (n = 8), normal ECFC-treated (n = 8), and MMD ECFC-treated (n = 8). ECFCs were injected into the cisterna magna. A laser Doppler flowmeter was used to evaluate cerebral blood flow, and a radial arm maze test was used to examine cognitive function. Neuropathological examinations of the hippocampus and agranular cortex were performed using hematoxylin and eosin and Luxol fast blue staining in addition to immunofluorescence with CD31, von Willebrand factor, NeuN, myelin basic protein, glial fibrillary acidic protein, and cleaved caspase-3 antibodies.RESULTSThe normal ECFC-treated group exhibited improvement in the restoration of cerebral perfusion and in behavior compared with the vehicle-treated and MMD ECFC-treated groups at the 12-week follow-up after the 2-VO surgery. The normal ECFC-treated group showed a greater amount of neovasculogenesis and neurogenesis, with less apoptosis, than the other groups.CONCLUSIONSThese results support the impaired functional recovery of MMD ECFCs compared with normal ECFCs in a CCH rat model. This in vivo study suggests the functional role of ECFCs in the pathogenesis of MMD.

// Ji Hoon Phi 1, 2, 3, * , Seung Ah Choi 1, 2, * , Pil Ae Kwak 1, 2 , Ji Yeoun Lee 1, 3, 4 , Kyu-Chang Wang 1, 3 , Do Won Hwang 5 and Seung-Ki Kim 1, 2, 3 1 Division of Pediatric Neurosurgery, Pediatric Clinical Neuroscience Center, Seoul National University Children’s Hospital, Seoul, Korea 2 Adolescent Cancer Center, Seoul National University Cancer Hospital, Seoul, Korea 3 Department of Neurosurgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea 4 Department of Anatomy, Seoul National University Hospital, Seoul, Korea 5 Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Korea * These authors have contributed equally to this work Correspondence to: Seung-Ki Kim, email: nsthomas@snu.ac.kr Do Won Hwang, email: hdw6592@hanmail.net Keywords: medulloblastoma, leptomeningeal seeding, histone deacetylase inhibitor, anti-cancer therapy, bioluminescence imaging Received: February 28, 2017 Accepted: April 25, 2017 Published: May 24, 2017 ABSTRACT Leptomeningeal seeding is a strong negative prognostic factor for medulloblastoma (MB). The mechanism of leptomeningeal seeding is unclear but may involve epigenetic regulation. In this study, we evaluated the feasibility of a histone deacetylase (HDAC) inhibitor, panobinostat, in the suppression of MB leptomeningeal seeding. Panobinostat decreased the cell viability and proliferation, inducing cell cycle arrest and apoptosis in MB cell lines. The migration and adhesion capabilities were significantly decreased. Panobinostat effectively down-regulated protein expression of CCND1 and ID3 which has been associated with leptomeningeal seeding of MB. After panobinostat treatment, neurophil-like cellular processes developed and expression of synaptophysin and NeuroD1 was increased, indicating neuronal differentiation. In MB leptomeningeal seeding in vivo model, the panobinostat-treated group showed significantly decreased spinal leptomeningeal seeding and a survival benefit. The findings demonstrate that panobinostat suppresses MB leptomeningeal seeding through the down-regulation of ID3 and the induction of neuronal differentiation. An HDAC inhibitor might be a potent treatment option for the treatment of MB patients with leptomeningeal seeding.

// Seung Ah Choi 1, 2 , Pil Ae Kwak 1, 2 , Chul-Kee Park 3 , Kyu-Chang Wang 1, 3 , Ji Hoon Phi 1, 2, 3 , Ji Yeoun Lee 1, 3, 4 , Chang Sik Lee 5 , Ju-Hee Lee 5 , Seung-Ki Kim 1, 2, 3 1 Division of Pediatric Neurosurgery, Pediatric Clinical Neuroscience Center, Seoul National University Children’s Hospital, Seoul, Korea 2 Adolescent Cancer Center, Seoul National University Cancer Hospital, Seoul, Korea 3 Department of Neurosurgery, Seoul National University Hospital, Seoul, Korea 4 Department of Anatomy, Seoul National University Hospital, Seoul, Korea 5 Chong Kun Dang Research Institute, CKD Pharmaceuticals, Gyeonggi-do, Korea Correspondence to: Seung-Ki Kim, email: nsthomas@snu.ac.kr Keywords: epigenetics, histone deacetylase inhibitor, glioblastoma Received: May 09, 2016 Accepted: November 01, 2016 Published: November 10, 2016 ABSTRACT There have been extensive efforts to improve the outcome of glioblastoma, but the prognosis of this disease has not been significantly altered to date. Histone deacetylase inhibitors (HDACIs) have been evaluated as promising anti-cancer drugs and regulate cell growth, cell cycle arrest and apoptosis in glioblastoma. Here, we demonstrated the therapeutic efficacy of a novel pan-HDACI, 7-ureido-N-hydroxyheptanamide derivative (CKD5), compared with traditional pan-HDACIs, such as suberoylanilide hydroxamic acid (SAHA) and trichostatin A (TSA), in vitro and in vivo . Compared with SAHA and TSA, CKD5 had improved cytotoxic effects and induced apoptosis, anti-proliferative activity and cell cycle arrest at G2/M phase. Furthermore, CKD5 significantly reduced tumor volume and prolonged the survival in vivo compared with TSA, suggesting improved anti-cancer efficacy among HDACIs. Our results demonstrate that the novel HDACI CKD5 is a promising therapeutic candidate for glioblastoma.

Human adipose tissue-derived mesenchymal stem cells expressing the secreted form of the tumor necrosis factor-related apoptosis-inducing ligand (hAT-MSC.sTRAIL) have demonstrated therapeutic activity against various tumors in preclinical studies. However, the limited expression of TRAIL death receptors remains a challenge. We evaluated the therapeutic efficacy of panobinostat in enhancing the sensitivity of hAT-MSC.sTRAIL-mediated apoptosis in malignant glioma. Panobinostat effectively inhibited all malignant glioma cells (IC50, 0.03–0.23 μM), enhancing the expression of DRs, but not in hAT-MSCs. Combined treatment with hAT-MSC.sTRAIL and panobinostat significantly suppressed cell viability and enhanced apoptosis. In a diffuse intrinsic pontine glioma (DIPG) mouse model, the combined treatment induced decreases in tumor volume and prolonged survival. Our study demonstrates that panobinostat enhances the expression of TRAIL DRs and potentiates the anti-cancer effects of hAT-MSC.sTRAIL.

Stem-cell based gene therapy is a promising novel therapeutic approach for inoperable invasive tumors, including brainstem glioma. Previously, we demonstrated the therapeutic potential of human adipose tissue-derived mesenchymal stem cells (hAT-MSC) genetically engineered to express a secreted form of tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL) against brainstem glioma. However, safety concerns should be comprehensively investigated before clinical applications of hAT-MSC.sTRAIL. At first, we injected stereotactically low (1.2 × 10(5) cells/18 μL), medium (2.4 × 10(5)/18 μL), or high dose (3.6 × 10(5)/18 μL) of hAT-MSC.sTRAIL into the brainstems of immunodeficient mice reflecting the plan of the future clinical trial. Local toxicity, systemic toxicity, secondary tumor formation, and biodistribution of hAT-MSC.sTRAIL were investigated. Next, presence of hAT-MSC.sTRAIL was confirmed in the brain and major organs at 4, 9, and 14 weeks in brainstem glioma-bearing mice. In the 15-week subchronic toxicity test, no serious adverse events in terms of body weight, food consumption, clinical symptom, urinalysis, hematology, clinical chemistry, organ weight, and histopathology were observed. In the 26-week tumorigenicity test, hAT-MSC.sTRAIL made no detectable tumors, whereas positive control U-87 MG cells made huge tumors in the brainstem. No remaining hAT-MSC.sTRAIL was observed in any organs examined, including the brainstem at 15 or 26 weeks. In brainstem glioma-bearing mice, injected hAT-MSC.sTRAIL was observed, but gradually decreased over time in the brain. The mRNA of human specific GAPDH and TRAIL was not detected in all major organs. These results indicate that the hAT-MSC.sTRAIL could be applicable to the future clinical trials in terms of biosafety.

Background The primary cause of treatment failure in medulloblastomas (MB) is the development of leptomeningeal dissemination (seeding). For translational research on MB seeding, one of the major challenges is the development of reliable experimental models that simulate the seeding and growth characteristics of MBs. To overcome this obstacle, we improved an experimental mouse model by intracisternal inoculation of human MB cells and monitoring with in vivo live images. Methods Human MB cells (UW426, D283 and MED8A) were transfected with a firefly luciferase gene and a Thy1.1 (CD90.1) marker linked with IRES under the control of the CMV promoter in a retroviral DNA backbone (effLuc). The MB-effLuc cells were injected into the cisterna magna using an intrathecal catheter, and bioluminescence images were captured. We performed histopathological analysis to confirm the extent of tumor seeding. Results The luciferase activity of MB-effLuc cells displayed a gradually increasing pattern, which correlated with a quantitative luminometric assay. Live imaging showed that the MB-effLuc cells were diffusely distributed in the cervical spinal cord and the lumbosacral area. All mice injected with UW426-effLuc, D283-effLuc and MED8A-effLuc died within 51 days. The median survival was 22, 41 and 12 days after injection of 1.2 × 106 UW426-effLuc, D283-effLuc and MED8A-effLuc cells, respectively. The histopathological studies revealed that the MB-effLuc cells spread extensively and diffusely along the leptomeninges of the brain and spinal cord, forming tumor cell-coated layers. The tumor cells in the subarachnoid space expressed a human nuclei marker and Ki-67. Compared with the intracerebellar injection method in which the subfrontal area and distal spinal cord were spared by tumor cell seeding in some mice, the intracisternal injection model more closely resembled the widespread leptomeningeal seeding observed in MB patients. Conclusion The results and described method are valuable resources for further translational research to overcome MB seeding.

Human adipose-derived mesenchymal stem cells expressing secreted form of the tumor necrosis factor-related apoptosis-inducing ligand (hAT-MSC.sTRAIL) have demonstrated therapeutic activity against various tumors. However, sTRAIL resistance remains a challenge in developing anticancer strategies. To solve this problem, many studies have tried to combine drugs to produce synergism or sensitize resistant cancer cells. Histone deacetylase inhibitors (HDACi) have been known to induce expression of TRAIL death receptors 4 and 5 (DR4/DR5). Herein, we evaluated the use of combined therapy of hAT-MSC.sTRAIL with HDAC inhibitor, panobinostat, in enhancing sensitivity to hAT-MSC.sTRAIL mediated apoptosis against the brainstem glioma. A sTRAIL was introduced into the characterized hAT-MSCs using electroporation. To confirm appropriate treatment concentration of panobinostat to the glioblastoma cells, dose titration was tested using cell viability assay. The therapeutic effect of single or combination treatment against glioblastoma was evaluated using primary cultured glioblastoma cells and cell lines. Orthotopic xenograft brainstem glioma mouse model was established using engineered firefly luciferase expressing tumor cells for bioluminescence in vivo imaging. Panobinostat induced anti-proliferative effects in dose and time-dependent manner (IC50 range, 0.05-0.2 μM) and effectively enhanced the expression of TRAIL DR4 and DR5, but not decoy receptors. Combined hAT-MSC.sTRAIL and panobinostat significantly decreased the tumor cell growth compared to each alone. Intriguingly, the combination treatment not only induced apoptosis but also autophagy. Using a preclinical brainstem mouse model, we confirmed that the combination of hAT-MSC.sTRAIL and panobinostat was safe and induced regression of tumor volume. Furthermore, the combination therapy prolonged the survival of brainstem glioma-bearing mice. Our results suggested that combination therapy of panobinostat enhanced the anti-cancer effect of hAT-MSC.sTRAIL and represent potential therapeutic approach to the brainstem glioma. Citation Format: Seung Ah Choi, Chanhee Lee, Pil Ae Kwak, Kyu-Chang Wang, Ji Hoon Phi, Ji Yeoun Lee, Sangjoon Chong, Seung-Ki Kim. Synergistic effects of combined treatment with hAT-MSC.sTRAIL and panobinostat in brainstem glioma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3195.

Disulfiram (DSF) has been studied as an anticancer drug and radiosensitizer. In our previous study, the therapeutic potential of DSF against atypical teratoid/rhabdoid tumor (AT/RT), one of the most aggressive forms of childhood cancer, had been confirmed using in vitro and in vivo studies. To develop more effective and safer therapy in AT/RT, we evaluated the sensitizing potential of DSF on radiation therapy (RT). The effect of DSF in low concentration alone and in combination with RT was investigated in vitro and vivo. Clonogenic assay, western blot analysis, autophagy assay and γ-H2AX foci staining were performed using several primary cultured AT/RT cells and cell lines. Also, in vivo study was performed using AT/RT orthotopic xenograft mouse model. Combination therapy with DSF and RT potently reduced clonogenicity and down-regulated protein expression of survivin and BCL2. The combination treatment strongly promoted the autophagic cell death and produced abundant γ-H2AX foci in all AT/RT cells. Moreover, the combination treatment significantly reduced the tumor growth and prolonged the survival rate compared to single treatment in AT/RT mouse model. Taken together, our results demonstrated that the combination therapy with DSF and RT has a synergistic therapeutic effect on AT/RT, suggesting a potential clinical application for AT/RT patients. Citation Format: Yeoung Eun Lee, Seung Ah Choi, Pil Ae Kwak, Kyu-Chang Wang, Ji Hoon Phi, Ji Yeoun Lee, Sangjoon Chong, Youn Joo Moon, Anshika Jangra, Kyeung Min Joo, Seung-Ki Kim. Combined disulfiram and radiation therapy against atypical teratoid/rhabdoid tumor. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3056.

Background and Purpose White-matter (WM) lesions are known to potentiate cognitive impairment in poststroke patients. The present study was designed to assess whether Ginkgo biloba extract (GB) and cilostazol, which were evaluated alone and in a combination formula (Renexin), can attenuate the WM lesions and cognitive decline caused by chronic hypoperfusion in the rat. Methods Animals were divided into five treatment groups: cilostazol (25 mg/kg/day), GB (20 mg/kg/day), Renexin (25 mg/kg/day cilostazol + 20 mg/kg/day GB), vehicle, and sham. The animals received the treatments orally 1 day after bilateral common carotid artery occlusion [two-vessel occlusion (2VO); except for the sham group, which underwent the surgery but the arteries were not occluded], and then the same dose every day for 21 days thereafter. Prior to sacrificing the rats, repetitive eight-arm radial maze testing was performed to examine their cognitive abilities. After drug administration and cognitive testing, brain tissues were isolated for Klüver-Barrera and terminal deoxynucleotidyl transferase-mediated biotin-dUTP nick end-labeling (TUNEL) staining, immunohistochemical assessment of glial fibrillary acidic protein (GFAP) and CD11b (OX-42), and to assay free-radical scavenging activity. Results We found that the significant WM lesions induced by 2VO was ameliorated significantly by treatment with cilostazol, GB, and Renexin, in association with increased TUNEL-positive cells. In addition, chronic cerebral hypoperfusion caused a large increase in the degree of GFAP and OX-42 immunoreactivity and free-radical activity in the optic tract. These abnormalities were significantly reversed by the three drugs, but most prominently by Renexin, suggesting a markedly enhanced or supra-additive effect of cilostazol and GB when administered together. Conclusions Significant attenuation of cytoarchitectural damage and apoptotic cell death was found with GB and cilostazol, but a markedly enhanced effect was seen for treatment with their combination in the WM of rat brains after bilateral occlusion of the common carotid arteries. We suggest that combination therapy with GB and cilostazol provides enhanced neuroprotective effects and induces subsequent cognitive improvement in patients with chronic ischemic conditions.