Preoperative 11 C-Methionine PET-MRI in Pediatric Infratentorial Tumors.

PURPOSE: MRI is the main imaging modality for pediatric brain tumors, but amino acid PET can provide additional information. Simultaneous PET-MRI acquisition allows to fully assess the tumor and lower the radiation exposure. Although symptomatic posterior fossa tumors are typically resected, the patient management is evolving and will benefit from an improved preoperative tumor characterization. We aimed to explore, in children with newly diagnosed posterior fossa tumor, the complementarity of the information provided by amino acid PET and MRI parameters and the correlation to histopathological results. PATIENTS AND METHODS: Children with a newly diagnosed posterior fossa tumor prospectively underwent a preoperative 11 C-methionine (MET) PET-MRI. Images were assessed visually and semiquantitatively. Using correlation, minimum apparent diffusion coefficient (ADC min ) and contrast enhancement were compared with MET SUV max . The diameter of the enhancing lesions was compared with metabolic tumoral volume. Lesions were classified according to the 2021 World Health Organization (WHO) classification. RESULTS: Ten children were included 4 pilocytic astrocytomas, 2 medulloblastomas, 1 ganglioglioma, 1 central nervous system embryonal tumor, and 1 schwannoma. All lesions showed visually increased MET uptake. A negative moderate correlation was found between ADC min and SUV max values ( r = -0.39). Mean SUV max was 3.8 (range, 3.3-4.2) in WHO grade 4 versus 2.5 (range, 1.7-3.0) in WHO grade 1 lesions. A positive moderate correlation was found between metabolic tumoral volume and diameter values ( r = 0.34). There was no correlation between SUV max and contrast enhancement intensity ( r = -0.15). CONCLUSIONS: Preoperative 11 C-MET PET and MRI could provide complementary information to characterize pediatric infratentorial tumors.

Medulloblastoma and high-grade glioma organoids for drug screening, lineage tracing, co-culture and in vivo assay.

Medulloblastoma and high-grade glioma represent the most aggressive and frequent lethal solid tumors affecting individuals during pediatric age. During the past years, several models have been established for studying these types of cancers. Human organoids have recently been shown to be a valid alternative model to study several aspects of brain cancer biology, genetics and test therapies. Notably, brain cancer organoids can be generated using genetically modified cerebral organoids differentiated from human induced pluripotent stem cells (hiPSCs). However, the protocols to generate them and their downstream applications are very rare. Here, we describe the protocols to generate cerebellum and forebrain organoids from hiPSCs, and the workflow to genetically modify them by overexpressing genes found altered in patients to finally produce cancer organoids. We also show detailed protocols to use medulloblastoma and high-grade glioma organoids for orthotopic transplantation and co-culture experiments aimed to study cell biology in vivo and in vitro, for lineage tracing to investigate the cell of origin and for drug screening. The protocol takes 60-65 d for cancer organoids generation and from 1-4 weeks for downstream applications. The protocol requires at least 3-6 months to become proficient in culturing hiPSCs, generating organoids and performing procedures on immunodeficient mice.

Infrared Spectroscopy as a Potential Diagnostic Tool for Medulloblastoma.

INTRODUCTION: Medulloblastoma (MB) is the most common malignant tumor of the central nervous system in childhood. FTIR spectroscopy provides a holistic view of the chemical composition of biological samples, including the detection of molecules such as nucleic acids, proteins, and lipids. This study evaluated the applicability of FTIR spectroscopy as a potential diagnostic tool for MB. MATERIALS AND METHODS: FTIR spectra of MB samples from 40 children (boys/girls: 31/9; age: median 7.8 years, range 1.5-21.5 years) treated in the Oncology Department of the Children's Memorial Health Institute in Warsaw between 2010 and 2019 were analyzed. The control group consisted of normal brain tissue taken from four children diagnosed with causes other than cancer. Formalin-fixed and paraffin-embedded tissues were sectioned and used for FTIR spectroscopic analysis. The sections were examined in the mid-infrared range (800-3500 cm-1) by ATR-FTIR. Spectra were analysed using a combination of principal component analysis, hierarchical cluster analysis, and absorbance dynamics. RESULTS: FTIR spectra in MB were significantly different from those of normal brain tissue. The most significant differences related to the range of nucleic acids and proteins in the region 800-1800 cm-1. Some major differences were also revealed in the quantification of protein conformations (α-helices, ß-sheets, and others) in the amide I band, as well as in the absorbance dynamics in the 1714-1716 cm-1 range (nucleic acids). It was not, however, possible to clearly distinguish between the various histological subtypes of MB using FTIR spectroscopy. CONCLUSIONS: MB and normal brain tissue can be distinguished from one another to some extent using FTIR spectroscopy. As a result, it may be used as a further tool to hasten and enhance histological diagnosis.

Can tumor treating fields induce DNA damage and reduce cell motility in medulloblastoma cell lines?

OBJECTIVE: Medulloblastoma (MB) is the most common malignant pediatric brain tumor and accounts for approximately 20% of all pediatric CNS tumors. Current multimodal treatment is associated with a 70%-90% 5-year survival rate; however, the prognosis for patients with tumor dissemination and recurrent MB remains poor. The majority of survivors exhibit long-term neurocognitive complications; thus, more effective and less toxic treatments are critically needed. Tumor treating fields (TTFields) are low-intensity, alternating electric fields that disrupt cell division through physical interactions with key molecules during mitosis. Side effects from TTField therapy are minimal, making it an ideal candidate for MB treatment. METHODS: To determine if TTFields can be an effective treatment for MB, the authors conducted an in vitro study treating multiple MB cell lines. Three MB molecular subgroups (SHH [sonic hedgehog], group 3, and group 4) were treated for 24, 48, and 72 hours at 100, 200, 300, and 400 kHz. Combinatorial studies were conducted with the small-molecule casein kinase 2 inhibitor CX-4945. RESULTS: TTFields reduced MB cell growth with an optimal frequency of 300 kHz, and the most efficacious treatment time was 72 hours. Treatment with TTFields dysregulated actin polymerization and corresponded with a reduction in cell motility and invasion. TTFields also induced DNA damage (γH2AX, 53BP1) that correlated with an increase in apoptotic cells. The authors discovered that CX-4945 works synergistically with TTFields to reduce MB growth. In addition, combining CX-4945 and TTFields increased the cellular actin dysregulation, which correlated with a decrease in MB migration. CONCLUSIONS: The findings of this study demonstrate that TTFields may be a novel and less toxic method to treat patients with MB.

Beta-blockers disrupt mitochondrial bioenergetics and increase radiotherapy efficacy independently of beta-adrenergic receptors in medulloblastoma.

BACKGROUND: Medulloblastoma is the most frequent brain malignancy of childhood. The current multimodal treatment comes at the expense of serious and often long-lasting side effects. Drug repurposing is a strategy to fast-track anti-cancer therapy with low toxicity. Here, we showed the ability of ß-blockers to potentiate radiotherapy in medulloblastoma with bad prognosis. METHODS: Medulloblastoma cell lines, patient-derived xenograft cells, 3D spheroids and an innovative cerebellar organotypic model were used to identify synergistic interactions between ß-blockers and ionising radiations. Gene expression profiles of ß-adrenergic receptors were analysed in medulloblastoma samples from 240 patients. Signaling pathways were explored by RT-qPCR, RNA interference, western blotting and RNA sequencing. Medulloblastoma cell bioenergetics were evaluated by measuring the oxygen consumption rate, the extracellular acidification rate and superoxide production. FINDINGS: Low concentrations of ß-blockers significantly potentiated clinically relevant radiation protocols. Although patient biopsies showed detectable expression of ß-adrenergic receptors, the ability of the repurposed drugs to potentiate ionising radiations did not result from the inhibition of the canonical signaling pathway. We highlighted that the efficacy of the combinatorial treatment relied on a metabolic catastrophe that deprives medulloblastoma cells of their adaptive bioenergetics capacities. This led to an overproduction of superoxide radicals and ultimately to an increase in ionising radiations-mediated DNA damages. INTERPRETATION: These data provide the evidence of the efficacy of ß-blockers as potentiators of radiotherapy in medulloblastoma, which may help improve the treatment and quality of life of children with high-risk brain tumours. FUNDING: This study was funded by institutional grants and charities.

Multivalent, Bispecific αB7-H3-αCD3 Chemically Self-Assembled Nanorings Direct Potent T Cell Responses against Medulloblastoma.

Few therapeutic options have been made available for treating central nervous system tumors, especially upon recurrence. Recurrent medulloblastoma is uniformly lethal with no approved therapies. Recent preclinical studies have shown promising results for eradicating various solid tumors by targeting the overexpressed immune checkpoint molecule, B7-H3. However, due to several therapy-related toxicities and reports of tumor escape, the full potential of targeting this pan-cancer antigen has yet to be realized. Here, we designed and characterized bispecific chemically self-assembling nanorings (CSANs) that target the T cell receptor, CD3ε, and tumor associated antigen, B7-H3, derived from the humanized 8H9 single chain variable fragment. We show that the αB7-H3-αCD3 CSANs increase T cell infiltration and facilitate selective cytotoxicity of B7-H3+ medulloblastoma spheroids and that activity is independent of target cell MHC class I expression. Importantly, nonspecific T cell activation against the ONS 2303 medulloblastoma cell line can be reduced by tuning the valency of the αCD3 targeted monomer in the oligomerized CSAN. Intraperitoneal injections of αB7-H3-αCD3 bispecific CSANs were found to effectively cross the blood-tumor barrier into the brain and elicit significant antitumor T cell activity intracranially as well as systemically in an orthotopic medulloblastoma model. Moreover, following treatment with αB7-H3-αCD3 CSANs, intratumoral T cells were found to primarily have a central memory phenotype that displayed significant levels of characteristic activation markers. Collectively, these results demonstrate the ability of our multivalent, bispecific CSANs to direct potent antitumor T cell responses and indicate its potential utility as an alternative or complementary therapy for immune cell targeting of B7-H3+ brain tumors.

Could dietary erucic acid lower risk of brain tumors? An epidemiological look to Chinese population with implications for prevention and treatment.

Erucic acid, an omega-9 monounsaturated fatty acid present in Brassicaceae plants (rapeseed and mustard oils) is highly consumed by the Chinese population and according to several global survey studies, its highest levels are encountered in the Chinese women's milk. Erucic acid is an activating ligand of the transcription factor PPARδ and an inhibitor of the transcriptional activity of PPARγ, which drive tumorigenesis of glioblastomas and medulloblastomas. In this theoretical review, we propose that erucic acid in diet may associate with the risk of brain tumors. High grade brain tumors including medulloblastomas in children and glioblastomas in adults have devastating consequences for human health and the latter tumors are practically incurable. CONCORD-3 epidemiological study recently published in 2021 revealed a low ratio of medulloblastomas in the pediatric age group and also a low ratio of glioblastomas in adults in the Chinese population. It is certain that such profound differences can not be attributed to a single genetic factor or a single nurture pattern. It is very likely that multiple hereditary, nutritional and environmental factors are responsible for these lower ratios; yet here we propose that erucic acid may be one of the contributing factors. If future epidemiological studies and animal models show antitumor activity of erucic acid regarding brain neoplasias, it can be utilized as a preventive strategy for populations possessing very high risks to develop brain tumors such as those harbouring hereditary syndromes increasing the vulnerability to develop such malignancies.

Inhibition of lncRNA NEAT1 sensitizes medulloblastoma cells to cisplatin through modulating the miR-23a-3p-glutaminase (GLS) axis.

Medulloblastoma (MB) is a commonly occurring brain malignancy in adolescence. Currently, the combination of chemotherapy with subsequent irradiation is a regular therapeutic strategy. However, high dosage of chemotherapy is associated with drug resistance and side effects. The long non-coding RNA nuclear paraspeckle assembly transcript 1 (NEAT1), which is frequently overexpressed in diverse human tumors, is correlated with worse survival rate in cancer patients. Currently, the precise roles of NEAT1 in MB and chemoresistance remain unclear. Our study aimed to investigate the biological functions of NEAT1 in cisplatin-resistant medulloblastoma. We report that NEAT1 was significantly upregulated in medulloblastoma patient specimens. Silencing NEAT1 significantly suppressed MB cell proliferation and sensitized MB cells to cisplatin. In cisplatin-resistant MB cell line, DAOY Cis R, NEAT1 expression, and glutamine metabolism were remarkably upregulated in cisplatin-resistant cells. Under low glutamine supply, cisplatin-resistant cells displayed increased cisplatin sensitivity. Bioinformatical analysis and luciferase assay uncovered that NEAT1 functions as a ceRNA of miR-23a-3p to downregulate its expressions in MB cells. Moreover, miR-23a-3p was apparently downregulated in MB patient tissues and cisplatin resistant MB cells. We identified GLS (glutaminase), a glutamine metabolism enzyme, was directly targeted by miR-23a-3p in MB cells. Rescue experiments demonstrated restoration of miR-23a-3p in NEAT1-overexpressing DAOY cisplatin resistant cells successfully overcame the NEAT1-promoted cisplatin resistance by targeting GLS. In general, our results revealed new molecular mechanisms for the lncRNA-NEAT1-mediated cisplatin sensitivity of MB.

Saikosaponin B1 and Saikosaponin D inhibit tumor growth in medulloblastoma allograft mice via inhibiting the Hedgehog signaling pathway.

Medulloblastoma (MB), accounting for nearly 10% of all childhood brain tumors, are implicated with aberrant activation of the Hedgehog (Hh) signaling pathway. Saikosaponin B1 (SSB1) and Saikosaponin D (SSD), two bioactive constituents of Radix Bupleuri, are reported to have many biological activities including anticancer activities. In our work, we evaluated the inhibition of SSB1 and SSD on MB tumor growth in allograft mice and explored the underlying mechanisms. The associated biological activity was investigated in Shh Light II cells, an Hh-responsive fibroblast cell line, using the Dual-Glo® Luciferase Assay System. First, SSB1 (IC50, 241.8 nM) and SSD (IC50, 168.7 nM) inhibited GLI-luciferase activity in Shh Light II cells stimulated with ShhN CM, as well as Gli1 and Ptch1 mRNA expression. In addition, both compounds suppressed the Hh signaling activity provoked by smoothened agonist (SAG) or excessive Smoothened (SMO) expression. Meanwhile, SSB1 and SSD did not inhibit glioma-associated oncogene homolog (GLI) luciferase activity activated by abnormal expression of downstream molecules, suppressor of fuse (SUFU) knockdown or GLI2 overexpression. Consequently, SSB1 (30 mg/kg, ip) and SSD (10 mg/kg, ip) displayed excellent in vivo inhibitory activity in MB allografts, and the tumor growth inhibition ratios were approximately 50% and 70%, respectively. Our findings, thus, identify SSB1 and SSD significantly inhibit tumor growth in MB models by inhibiting the Hedgehog pathway through targeting SMO.

Omega-3 fatty acids decrease CRYAB, production of oncogenic prostaglandin E2 and suppress tumor growth in medulloblastoma.

AIMS: Medulloblastoma (MB) is one of the most common malignant central nervous system tumors of childhood. Despite intensive treatments that often leads to severe neurological sequelae, the risk for resistant relapses remains significant. In this study we have evaluated the effects of the ω3-long chain polyunsaturated fatty acids (ω3-LCPUFA) docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) on MB cell lines and in a MB xenograft model. MAIN METHODS: Effects of ω3-LCPUFA treatment of MB cells were assessed using the following: WST-1 assay, cell death probes, clonogenic assay, ELISA and western blot. MB cells were implanted into nude mice and the mice were randomized to DHA, or a combination of DHA and EPA treatment, or to control group. Treatment effects in tumor tissues were evaluated with: LC-MS/MS, RNA-sequencing and immunohistochemistry, and tumors, erythrocytes and brain tissues were analyzed with gas chromatography. KEY FINDINGS: ω3-LCPUFA decreased prostaglandin E2 (PGE2) secretion from MB cells, and impaired MB cell viability and colony forming ability and increased apoptosis in a dose-dependent manner. DHA reduced tumor growth in vivo, and both PGE2 and prostacyclin were significantly decreased in tumor tissue from treated mice compared to control animals. All ω3-LCPUFA and dihomo-γ-linolenic acid increased in tumors from treated mice. RNA-sequencing revealed 10 downregulated genes in common among ω3-LCPUFA treated tumors. CRYAB was the most significantly altered gene and the downregulation was confirmed by immunohistochemistry. SIGNIFICANCE: Our findings suggest that addition of DHA and EPA to the standard MB treatment regimen might be a novel approach to target inflammation in the tumor microenvironment.

Drug Screening Assays on Medulloblastoma Stem Cells Using Compound Libraries.

Conventional chemotherapies for medulloblastoma are restricted to only proliferative population leaving the cancer stem cells unscathed. This shortcoming of the traditional therapies is attributed to the relapse and metastasis of the cancer. The current research is entirely focused on the screening of therapeutic agents that can restrict and target the self-renewal potential of the cancer stem cells. The advances in drug screening strategies have led to high-throughput screening which provide a robust and expeditious platform to screen potential compounds against cancer stem cells. In this book chapter, we describe two in vitro assays that are routinely used to measure the cell killing and anti-self-renewal activity of the compounds against the cancer stem cells. Combining these assays with high-throughput screening offers a rapid, reliable, and inexpensive approach to screen potential compounds against cancer stem cells and to overcome the limitation of conventional chemotherapeutic agents.

Clinical Audit of Survival Outcomes and Prognostic Factors in Adolescents and Adults with Medulloblastoma.

Purpose: Medulloblastomas, comprising 20%-25% of all primary brain tumors in children are much rarer in adulthood. Disease biology varies substantially across different age groups; however, owing to rarity, adults with medulloblastoma are traditionally treated using pediatric protocols. This is a retrospective audit of adolescent and adult medulloblastoma from a comprehensive cancer center. Methods: Data regarding demography, clinical presentation, imaging characteristics, histopathological features, molecular profiling, risk stratification, treatment details, and outcomes were retrieved from medical records. All time-to-event outcomes were analyzed using Kaplan-Meier method and compared with the log-rank test. Univariate and multivariate analysis of relevant prognostic factors was done with p value <0.05 being considered statistically significant. Results: A total of 162 patients ≥15 years of age with medulloblastoma were included. The median age was 25 years (range: 15-59 years) with leptomeningeal metastases seen in 31 (19%) patients at initial diagnosis. Following surgery, patients were treated with appropriate risk-stratified adjuvant therapy comprising of craniospinal irradiation plus boost with or without systemic chemotherapy. At a median follow-up of 50 months, 5-year Kaplan-Meier estimates of progression-free survival and overall survival were 53.5% and 59.5%, respectively. The addition of adjuvant systemic chemotherapy did not impact upon survival in standard-risk medulloblastoma. High-risk (HR) disease and anaplastic histology emerged as significant and independent predictors of poor survival on multivariate analysis. Conclusion: Medulloblastoma is a rare tumor in adolescents and adults with key differences in disease biology and resultant outcomes compared with the pediatric population. Contemporary management comprising maximal safe resection followed by appropriate risk-stratified adjuvant therapy provides acceptable survival outcomes.

Challenges to paediatric tuberculosis care as perceived by health workers in Kano, North-western Nigeria

uberculosis (TB) remains the world's deadliest infectious disease that affects a third of the world's population and newly infected an estimated 10 million people in 2018. The number of TB infected Nigerians ranks sixth in the world and first in Africa. Kano State has the highest Nigerian TB prevalence. I aimed to identify Paediatric TB care challenges as perceived by Kano Medical and DOT health care providers. The study design was prospective, descriptive and cross sectional involving structured questionnaire interviews of 43 healthcare providers, during TB supervision visits of 10 Health facilities in Kano. Generated data was entered, validated and analysed using the STATA 13 statistical software package. The sample size was convenient, since it is the number of all the health providers working in the facilities assigned to the author for supervision under a supervision contract with KNCV in 2017. Of the 43 respondents, there were 26 males, with a M: F ratio of 1.5: 1. Those health workers aged from 30 and 40 years constituted 58% of respondents. The staff cadre of respondents comprised of Community Health Extension Workers [CHEW] (40%), doctors (30%) and nurses (3%). Up to 51% of respondents had over 10 years health worker experience and greater than 36 months Child TB DOT care provision. The most commonly identified challenges to paediatric TB care included poor health knowledge (97.7%), poor health seeking behaviour (95.4%), poverty (95.4%), the inability of children to cough up sputum 95.4%, late presentation (90.7%), contact tracing logistics (90.7 %), patient and community factors of stigma and discrimination (86%) and poor health worker paediatric TB knowledge (70%). Perceived health worker challenges to effective Paediatric TB care were the adult orientation of the TB programme and its contact tracing logistic challenges, inadequate health worker Paediatric TB knowledge, children's inability to cough up sputum, poverty, poor patient TB health knowledge, community stigma and discrimination, poor health seeking behaviour and late presentation.

Systems pharmacogenomics identifies novel targets and clinically actionable therapeutics for medulloblastoma.

BACKGROUND: Medulloblastoma (MB) is the most common malignant paediatric brain tumour and a leading cause of cancer-related mortality and morbidity. Existing treatment protocols are aggressive in nature resulting in significant neurological, intellectual and physical disabilities for the children undergoing treatment. Thus, there is an urgent need for improved, targeted therapies that minimize these harmful side effects. METHODS: We identified candidate drugs for MB using a network-based systems-pharmacogenomics approach: based on results from a functional genomics screen, we identified a network of interactions implicated in human MB growth regulation. We then integrated drugs and their known mechanisms of action, along with gene expression data from a large collection of medulloblastoma patients to identify drugs with potential to treat MB. RESULTS: Our analyses identified drugs targeting CDK4, CDK6 and AURKA as strong candidates for MB; all of these genes are well validated as drug targets in other tumour types. We also identified non-WNT MB as a novel indication for drugs targeting TUBB, CAD, SNRPA, SLC1A5, PTPRS, P4HB and CHEK2. Based upon these analyses, we subsequently demonstrated that one of these drugs, the new microtubule stabilizing agent, ixabepilone, blocked tumour growth in vivo in mice bearing patient-derived xenograft tumours of the Sonic Hedgehog and Group 3 subtype, providing the first demonstration of its efficacy in MB. CONCLUSIONS: Our findings confirm that this data-driven systems pharmacogenomics strategy is a powerful approach for the discovery and validation of novel therapeutic candidates relevant to MB treatment, and along with data validating ixabepilone in PDX models of the two most aggressive subtypes of medulloblastoma, we present the network analysis framework as a resource for the field.

Identification of pseudolaric acid B as a novel Hedgehog pathway inhibitor in medulloblastoma.

Aberrant activation of the Hedgehog (Hh) pathway is implicated in the pathogenesis and development of multiple cancers, especially Hh-driven medulloblastoma (MB). Smoothened (SMO) is a promising therapeutic target of the Hh pathway in clinical cancer treatment. However, SMO mutations frequently occur, which leads to drug resistance and tumor relapse. Novel inhibitors that target both the wild-type and mutant SMO are in high demand. In this study, we identified a novel Hh pathway inhibitor, pseudolaric acid B (PAB), which significantly inhibited the expression of Gli1 and its transcriptional target genes, such as cyclin D1 and N-myc, thus inhibiting the proliferation of DAOY and Ptch1+/- primary MB cells. Mechanistically, PAB can potentially bind to the extracellular entrance of the heptahelical transmembrane domain (TMD) of SMO, based on molecular docking and the BODIPY-cyclopamine binding assay. Further, PAB also efficiently blocked ciliogenesis, demonstrating the inhibitory effects of PAB on the Hh pathway at multiple levels. Thus, PAB may overcome drug-resistance induced by SMO mutations, which frequently occurs in clinical setting. PAB markedly suppressed tumor growth in the subcutaneous allografts of Ptch1+/- MB cells. Together, our results identified PAB as a potent Hh pathway inhibitor to treat Hh-dependent MB, especially cases resistant to SMO antagonists.

Anticancer Effects of Viscum album Fraxini Extract on Medulloblastoma Cells in vitro.

BACKGROUND: Mistletoe therapy is frequently administered as a supportive treatment in diverse pediatric cancer entities including brain tumors. Medulloblastoma is the most common brain tumor in childhood. Its high risk to metastasize and its long-term sequelae caused by aggressive chemo- or radiotherapies are still challenging. MATERIAL AND METHODS: Effects of a lectin-rich mistletoe extract, abnobaVISCUM Fraxini, were investigated in two medulloblastoma cell lines (Daoy and ONS-76). Responsiveness of tumor cells was assessed by cell viability assays and xCELLigence real-time analyses. Moreover, impacts on proliferation, cell cycle and apoptosis were investigated. Apoptosis was studied by staining of vital mitochondria and assessing the involvement of caspases. In addition, effects on migration and invasion were analyzed. RESULTS: Both medulloblastoma cell lines were more susceptible to treatment with the mistletoe extract than a nontumorigenic fibroblast cell line. In mistletoe-sensitive Daoy cells, reduction of proliferation and induction of caspase-mediated apoptosis were observed upon administration of 0.05 and 0.5 mg/mL abnobaVISCUM Fraxini treatment, respectively. Furthermore, mistletoe extract inhibited migration and invasion properties in Daoy and significantly impaired invasive capabilities of ONS-76 cells. CONCLUSION: AbnobaVISCUM Fraxini has cell line dependent antitumoral effects in medulloblastoma models. These results call for further investigations, to reveal mechanistic insights into antitumorigenic properties of mistletoe extracts.

Drug Repurposing in Medulloblastoma: Challenges and Recommendations.

OPINION STATEMENT: Medulloblastoma is the most frequently diagnosed primary malignant brain tumor among children. Currently available therapeutic strategies are based on surgical resection, chemotherapy, and/or radiotherapy. However, majority of patients quickly develop therapeutic resistance and are often left with long-term therapy-related side effects and sequelae. Therefore, there remains a dire need to develop more effective therapeutics to overcome the acquired resistance to currently available therapies. Unfortunately, the process of developing novel anti-neoplastic drugs from bench to bedside is highly time-consuming and very expensive. A wide range of drugs that are already in clinical use for treating non-cancerous diseases might commonly target tumor-associated signaling pathways as well and hence be of interest in treating different cancers. This is referred to as drug repurposing or repositioning. In medulloblastoma, drug repurposing has recently gained a remarkable interest as an alternative therapy to overcome therapy resistance, wherein existing non-tumor drugs are being tested for their potential anti-neoplastic effects outside the scope of their original use.

Prostaglandin E1 Inhibits GLI2 Amplification-Associated Activation of the Hedgehog Pathway and Drug Refractory Tumor Growth.

Aberrant activation of the Hedgehog (HH) signaling pathway underlines the initiation and progression of a multitude of cancers. The effectiveness of the leading drugs vismodegib (GDC-0449) and sonidegib (LDE225), both Smoothened (SMO) antagonists, is compromised by acquisition of mutations that alter pathway components, notably secondary mutations in SMO and amplification of GLI2, a transcriptional mediator at the end of the pathway. Pharmacologic blockade of GLI2 activity could ultimately overcome these diversified refractory mechanisms, which would also be effective in a broader spectrum of primary tumors than current SMO antagonists. To this end, we conducted a high-content screening directly analyzing the ciliary translocation of GLI2, a key event for GLI2 activation in HH signal transduction. Several prostaglandin compounds were shown to inhibit accumulation of GLI2 within the primary cilium (PC). In particular, prostaglandin E1 (PGE1), an FDA-approved drug, is a potent GLI2 antagonist that overcame resistance mechanisms of both SMO mutagenesis and GLI2 amplification. Consistent with a role in HH pathway regulation, EP4 receptor localized to the PC. Mechanistically, PGE1 inhibited HH signaling through the EP4 receptor, enhancing cAMP-PKA activity, which promoted phosphorylation and degradation of GLI2 via the ubiquitination pathway. PGE1 also effectively inhibited the growth of drug refractory human medulloblastoma xenografts. Together, these results identify PGE1 and other prostaglandins as potential templates for complementary therapeutic development to circumvent resistance to current generation SMO antagonists in use in the clinic. SIGNIFICANCE: These findings show that PGE1 exhibits pan-inhibition against multiple drug refractory activities for Hedgehog-targeted therapies and elicits significant antitumor effects in xenograft models of drug refractory human medulloblastoma mimicking GLI2 amplification.

Geniposide exhibits anticancer activity to medulloblastoma cells by downregulating microRNA-373.

BACKGROUND: Medulloblastoma is a common tumor originates from central nervous system in children with metastatic potential. Geniposide is the major active ingredient separated from the fruit of Gardenia jasminoides Ellis. Herein, we tested the possible anticancer activity of geniposide on human medulloblastoma cells, as well as the potential underlying molecular mechanisms. METHODS: Firstly, followed by geniposide incubation, cell viability, proliferation, apoptosis, migration, and invasion of medulloblastoma Daoy cells, along with microRNA-373 (miR-373) expression were tested, respectively. Then, the influences of miR-373 overexpression in the reduction of medulloblastoma cell proliferation, migration, and invasion and the elevation of apoptosis, triggered by geniposide treatment, were re-investigated. Finally, the Ras/Raf/MEK/ERK pathway activity was analyzed. RESULTS: Geniposide treatment inhibited medulloblastoma cell viability, proliferation, migration, and invasion, but promoted cell apoptosis. Surprisingly, miR-373 expression in medulloblastoma cells was obviously downregulated by geniposide treatment. miR-373 overexpression reversed the effects of geniposide on Daoy cells. Furthermore, geniposide hindered the Ras/Raf/MEK/ERK pathway by downregulating miR-373 expression. CONCLUSION: Geniposide exhibited anticancer activity on human medulloblastoma cells and blocked Ras/Raf/MEK/ERK pathway by downregulating miR-373 expression.

Icariin inhibits proliferation, migration, and invasion of medulloblastoma DAOY cells by regulation of SPARC.

Icariin (ICA) is obtained from Epimedium brevicornu maxim and exploited to remedy miscellaneous cancers. But the role of ICA in medulloblastoma remains hazy. The research delved into the antitumor activity of ICA in medulloblastoma DAOY cells. ICA with diverse concentrations was utilized to stimulate DAOY cells, and the biological functions of ICA in medulloblastoma DAOY cells were examined. Then, the relative SPARC expression was determined in ICA-managed DAOY cells, and the pc-SPARC vector was transfected into DAOY cells to further probe the influence of SPARC and JAK1/STAT3 and PI3K/AKT pathways in ICA-managed DAOY cells. A xenograft model was established to investigate the function of ICA in vivo. ICA restrained cell viability, expedited apoptosis, prohibited cell migration and invasion, and meanwhile affected the associative factors expression in DAOY cells. Additionally, SPARC expression was declined in ICA-stimulated DAOY cells. Overexpressed SPARC reversed the functions of ICA in above-involved cell behaviors of DAYO cells and the correlative protein levels. Besides, ICA notably frustrated JAK1/STAT3 and PI3K/AKT activations in DAOY cells. Beyond that, ICA prohibited tumor formation in vivo. The results concluded that ICA exhibited the antitumor activity in DAOY cells via decreasing SPARC and inactivating JAK1/STAT3 and PI3K/AKT pathways.