Summary Medulloblastoma, the most common malignant pediatric brain tumour, is currently treated with non-specific cytotoxic therapies including surgery, whole brain radiation, and aggressive chemotherapy. As medulloblastoma exhibits marked intertumoural heterogeneity, with at least four distinct molecular variants, prior attempts to identify targets for therapy have been underpowered due to small samples sizes. Here we report somatic copy number aberrations (SCNAs) in 1087 unique medulloblastomas. SCNAs are common in medulloblastoma, and are predominantly subgroup enriched. The most common region of focal copy number gain is a tandem duplication of the Parkinson’s disease gene SNCAIP, which is exquisitely restricted to Group 4α. Recurrent translocations of PVT1, including PVT1-MYC and PVT1-NDRG1 that arise through chromothripsis are restricted to Group 3. Numerous targetable SCNAs, including recurrent events targeting TGFβ signaling in Group 3, and NF-κB signaling in Group 4 suggest future avenues for rational, targeted therapy.

Purpose: Medulloblastoma, a malignant pediatric brain tumor, is incurable in about one third of patients despite multimodal treatments. In addition, current therapies can lead to long-term disabilities. Based on studies of the extensive tropism of neural stem cells (NSC) toward malignant gliomas and the secretion of growth factors common to glioma and medulloblastoma, we hypothesized that NSCs could target medulloblastoma and be used as a cellular therapeutic delivery system. Experimental Design: The migratory ability of HB1.F3 cells (an immortalized, clonal human NSC line) to medulloblastoma was studied both in vitro and in vivo. As proof-of-concept, we used HB1.F3 cells engineered to secrete the prodrug activating enzyme cytosine deaminase. We investigated the potential of human NSCs to deliver a therapeutic gene and reduce tumor growth. Results: The migratory capacity of HB1.F3 cells was confirmed by an in vitro migration assay, and corroborated in vivo by injecting chloromethylbenzamido-Dil^labeled HB1.F3 cells into the hemisphere contralateral to established medulloblastoma in nude mice. In vitro studies showed the therapeutic efficacy of HB1.F3-CD on Daoy cells in coculture experiments. In vitro therapeutic studies were conducted in which animals bearing intracranial medulloblastoma were injected ipsilaterally with HB1.F3-CD cells followed by systemic 5-flourocytosine treatment. Histologic analyses showed that human NSCs migrate to the tumor bed and its boundary, resulting in a 76% reduction of tumor volume in the treatment group (P < 0.01).Conclusion: These studies show for the first time the potential of human NSCs as an effective delivery system to target and disseminate therapeutic agents to medulloblastoma.Medulloblastoma is the most common childhood malignant brain tumor. Although multimodal treatments, including radical surgical resection followed by radiation and chemotherapy, have substantially improved the survival rate for this disease, it remains incurable in about one third of patients.These treatments are also toxic and can lead to long-term disabilities (1, 2). The main cause of death is recurrence associated with tumor dissemination, at which point current therapeutic options have little efficacy (3, 4). Consequently, there is substantial need for novel, effective, low-toxicity therapies for children with medulloblastoma.The discovery of the inherent tumor-tropic properties of neural stem cells (NSC) could serve as a novel adjuvant strategy to current medulloblastoma treatments. Recent studies have shown that NSCs have the capacity to target therapeutic genes to brain tumors, such as malignant glioma (5 -13) and melanoma brain metastasis (14). We have expanded these investigations to determine whether NSCs are capable of targeting medulloblastoma in an orthotopic xenograft animal model. Therapeutic proof-of-concept studies were done using cytosine deaminase (CD) -producing NSCs and systemic 5-fluorocytosine (5-FC) prodrug administration. Our results show for the first time the pote...

Our results indicate that an early diagnosis and active intervention before establishment of irreversible hemodynamic change are essential to achieve a favorable clinical outcome in children with MMD.

There were distinctive expression patterns of matrixins, cytokines and angiogenic factors in MMD patients, which seemed to correlate with disease pathogenesis. The balance between MMPs and TIMPs was disrupted in MMD and correlated with disease pathogenesis. Increased plasma levels of MCP-1 and VEGF in MMD patients may play a role in the recruitment of vascular progenitor cells and in the formation of collateral vessels.

Young-age MMD demonstrates rapid disease progression and results in poor clinical outcomes. These findings indicate the necessity of early surgery for young patients with MMD; however, the actual benefits should be verified with additional controlled studies, with long-term follow-up monitoring.

Glioblastoma is among the most aggressive and treatment resistant of all human cancers. Conventional therapeutic approaches are unsuccessful because of diffuse infiltrative invasion of glioma tumor cells into normal brain parenchyma. Stem cell-based therapies provide a promising approach for the treatment of malignant gliomas because of their migratory ability to invasive tumor cells. Our therapeutic strategy was to use human bone marrowderived mesenchymal stromal cells (hMSCs) as a cellular vehicle for the targeted delivery and local production of the biologic agent tumor necrosis factor-related apoptosisinducing ligand (TRAIL) at the glioma tumor site. hMSCs were transduced with a lentivirus expressing secretable TRAIL (S-TRAIL) and mCherry (red fluorescent protein). Our results clearly demonstrate the retention of tumor tropic ability of hMSC S-TRAIL cells by in vitro and in vivo migration assays. In vitro assays confirmed the expression, release, and biological activity of S-TRAIL produced by hMSC S-TRAIL cells. For the in vivo assessment of therapeutic efficacy, hMSCs were injected ipsilateral to an established intracranial glioma tumor in a mouse xenograft model. Genetically engineered hMSC S-TRAIL cells were effective in inhibiting intracranial U87 glioma tumor growth (81.6%) in vivo and resulted in significantly longer animal survival. Immunohistochemical studies demonstrated significant, eight fold greater tumor cell apoptosis in the hMSC S-TRAIL-treated group than in controls. Our study demonstrates the therapeutic efficacy of hMSC S-TRAIL cells and confirms that hMSCs can serve as a powerful cell-based delivery vehicle for the site-specific release of therapeutic proteins. STEM CELLS

Gliomas are associated with high mortality because of their exceedingly invasive character. As these tumors acquire their invasiveness from low-grade tumors, it is very important to understand the detailed molecular mechanisms of invasion onset. Recent evidences suggest the significant role of microRNAs in tumor invasion. Thus, we hypothesized that deregulation of microRNAs may be important for the malignant progression of gliomas. We found that the aberrant expression of miR-21 is responsible for glioma invasion by disrupting the negative feedback circuit of Ras/MAPK signaling, which is mediated by Spry2. Upregulation of miR-21 was triggered by tumor microenvironmental factors such as hyaluronan and growth factors in glioma cells lacking functional phosphatase and tensin homolog (PTEN), but not harboring wild-type PTEN. Consistently with these in vitro results, Spry2 protein levels were significantly decreased in 79.7% of invasive WHO grade II-IV human glioma tissues, but not in non-invasive grade I and normal tissues. The Spry2 protein levels were not correlated with their mRNA levels, but inversely correlated with miR-21 levels. Taken together, these results suggest that the posttranscriptional regulation of Spry2 by miR-21 has an essential role on the malignant progression of human gliomas. Thus, Spry2 may be a novel therapeutic target for treating gliomas.

Purpose: Brainstem gliomas are usually inoperable and have a dismal prognosis.Based on the robust tropisms of neural stem cells (NSC) and mesenchymal stem cells (MSC) to brain tumors, we compared the tumor-tropic migratory capacities of these stem cells and evaluated the therapeutic potential of genetically engineered human NSCs encoding cytosine deaminase (CD) and IFNβ against brainstem gliomas. Experimental Design: The directed migratory capacities of NSCs and MSCs to brainstem glioma (F98) were evaluated both in vitro and in vivo. The human NSCs (HB1. F3) and various human MSCs, such as bone marrow-derived MSCs (HM3.B10), adipose tissue-derived MSCs, and umbilical cord blood-derived MSCs, were tested. Human fibroblast cells (HFF-1) were used as the negative control. As a proof of concept, the bioactivity of HB1.F3-CD-IFNβ was analyzed with a cell viability assay, and animals with brainstem gliomas were injected with HB1.F3-CD-IFNβ cells followed by systemic 5-fluorocytosine treatment.Results: In an in vitro modified Transwell migration assay and in vivo stem cell injection into established brainstem gliomas in rats, all the stem cells showed a significant migratory capacity compared with that of the control (P < 0.01). Histologic analysis showed a 59% reduction in tumor volume in the HB1.F3-CD-IFNβ-treated group (P < 0.05). Apoptotic cells were increased 2.33-fold in animals treated with HB1.F3-CD-IFNβ compared with the respective control groups (P < 0.01). Conclusion: The brainstem glioma-tropic migratory capacities of MSCs from various sources were similar to those of NSCs. Genetically engineered NSCs show therapeutic efficacy against brainstem gliomas.