NRP1 AS A POTENTIAL MOLECULAR TARGET FOR MEDULOBLASTOMA / NRP1 COMO POTENCIAL ALVO MOLECULAR PARA MEDULOBLASTOMA

Introdução : O meduloblastoma é um tumor maligno, altamente agressivo e de rápido crescimento que surge no cerebelo ou no assoalho do quarto ventrículo e tronco encefálico, principalmente em crianças. Mesmo com os avanços na terapia, a morbidade e a mortalidade continuam sendo um grande desafio. Portanto, novos tratamentos são necessários para reduzir esses resultados. Objetivo : Revisar a relação NRP1 (neuropilina 1) e meduloblastoma como potencial alvo terapêutico e, também, com sobrevida global. Method: This is a narrative review carried out in the PubMed and Scielo databases. The search used the following keywords: "neuropilins, medulloblastoma, brain tumors, pediatrics". The inclusion criteria were review articles, experimental studies, pre-clinical and clinical research, in English and Portuguese, and available in full text. The selected articles were analyzed based on the technologies covered, future perspectives and challenges mentioned, diseases mentioned and the central idea of the article. Result: 30 articles were included. Conclusion: Medulloblastomas have high transcriptional levels of neuropilin (NRP1) and their low levels are related to lower overall survival, especially in SHH. In this sense, NRP1 and its complex action system appear as a potential target for oncological therapies for brain tumors.

Introdução : Meduloblastoma é um tumor maligno, altamente agressivo e de rápido crescimento que surge no cerebelo ou no assoalho do quarto ventrículo e tronco cerebral, especialmente em crianças. Mesmo com os avanços na terapia, a morbimortalidade permanece um grande desafio. Por isso, novos tratamentos são necessários para reduzir esses estágios. Objetivo : Revisar a relação NRP1 (neuropilina 1) e meduloblastoma como potencial alvo terapêutico e, também, com sobrevida global. Método : Trata-se de revisão narrativa realizada nas bases de dados PubMed e Scielo. A busca utilizou as seguintes palavras-chave: " neuropilinas, meduloblastoma, tumores malignos, pediatria ". Os critérios de inclusão foram artigos de revisão, estudos experimentais, pesquisas pré-clínicas e clínicas, em inglês e português, e disponíveis em texto completo. Os artigos selecionados foram analisados ​​com base nas tecnologias abordadas, perspectivas futuras e desafios conceituais, doenças referidas e ideia central do artigo. Resultado : Foram incluídos 30 artigos Conclusão : Os meduloblastomas possuem altos níveis transcricionais de neuropilina (NRP1) e seus baixos níveis relacionados com a menor sobrevida global, especialmente nos SHH. Nesse sentido, o NRP1 e seu complexo sistema de atuação aparecem como alvo potencial de terapias oncológicas para tumores específicos.

Modulation of Viability, Proliferation, and Stemness by Rosmarinic Acid in Medulloblastoma Cells: Involvement of HDACs and EGFR.

Medulloblastoma (MB) is a heterogeneous group of malignant pediatric brain tumors, divided into molecular groups with distinct biological features and prognoses. Currently available therapy often results in poor long-term quality of life for patients, which will be afflicted by neurological, neuropsychiatric, and emotional sequelae. Identifying novel therapeutic agents capable of targeting the tumors without jeopardizing patients' quality of life is imperative. Rosmarinic acid (RA) is a plant-derived compound whose action against a series of diseases including cancer has been investigated, with no side effects reported so far. Previous studies have not examined whether RA has effects in MB. Here, we show RA is cytotoxic against human Daoy (IC50 = 168 µM) and D283 (IC50 = 334 µM) MB cells. Exposure to RA for 48 h reduced histone deacetylase 1 (HDAC1) expression while increasing H3K9 hyperacetylation, reduced epidermal growth factor (EGFR) expression, and inhibited EGFR downstream targets extracellular-regulated kinase (ERK)1/2 and AKT in Daoy cells. These modifications were accompanied by increased expression of CDKN1A/p21, reduced expression of SOX2, and a decrease in proliferative rate. Treatment with RA also reduced cancer stem cell markers expression and neurosphere size. Taken together, our findings indicate that RA can reduce cell proliferation and stemness and induce cell cycle arrest in MB cells. Mechanisms mediating these effects may include targeting HDAC1, EGFR, and ERK signaling, and promoting p21 expression, possibly through an increase in H3K9ac and AKT deactivation. RA should be further investigated as a potential anticancer agent in experimental MB.

Low Expression of the NRP1 Gene Is Associated with Shorter Overall Survival in Patients with Sonic Hedgehog and Group 3 Medulloblastoma.

Medulloblastoma (MB) is the most common type of malignant pediatric brain tumor. Neuropilin-1 (NRP1), encoded by the NRP1 gene, is a transmembrane glycoprotein overexpressed in several types of cancer. Previous studies indicate that NRP1 inhibition displays antitumor effects in MB models and higher NRP1 levels are associated with poorer prognosis in MB patients. Here, we used a large MB tumor dataset to examine NRP1 gene expression in different molecular subgroups and subtypes of MB. We found overall widespread NRP1 expression across MB samples. Tumors in the sonic hedgehog (SHH) subgroup showed significantly higher NRP1 transcript levels in comparison with Group 3 and Group 4 tumors, with SHH samples belonging to the α, ß, Δ, and γ subtypes. When all MB subgroups were combined, lower NRP1 expression was associated with significantly shorter patient overall survival (OS). Further analysis showed that low NRP1 was related to poorer OS, specifically in MB subgroups SHH and Group 3 MB. Our findings indicate that patients with SHH and Group 3 tumors that show lower expression of NRP1 in MB have a worse prognosis, which highlights the need for subgroup-specific investigation of the NRP1 role in MB.

ZEB1 is a Subgroup-Specific Marker of Prognosis and Potential Drug Target in Medulloblastoma.

Medulloblastoma (MB) is a malignant brain tumor that afflicts mostly children and adolescents and presents four distinct molecular subgroups, known as WNT, SHH, Group 3, and Group 4. ZEB1 is a transcription factor that promotes the expression of mesenchymal markers while restraining expression of epithelial and polarity genes. Because of ZEB1 involvement in cerebellum development, here we investigated the role of ZEB1 in MB. We found increased expression of ZEB1 in MB tumor samples compared to normal cerebellar tissue. Expression was higher in the SHH subgroup when compared to all other MB molecular subgroups. High ZEB1 expression was associated with poor prognosis in Group 3 and Group 4, whereas in patients with WNT tumors poorer prognosis were related to lower ZEB1 expression. There was a moderate correlation between ZEB1 and MYC expression in Group 3 and Group 4 MB. Treatment with the immunomodulator and histone deacetylase (HDAC) inhibitor fingolimod (FTY720) reduced ZEB1 expression specifically in D283 cells, which are representative of Group 3 and Group 4 MB. These findings reveal novel subgroup-specific associations of ZEB1 expression with survival in patients with MB and suggest that ZEB1 expression can be reduced by pharmacological agents that target HDAC activity.

Oncogenic functions of ZEB1 in pediatric solid cancers: interplays with microRNAs and long noncoding RNAs.

The transcription factor Zinc finger E-box binding 1 (ZEB1) displays a range of regulatory activities in cell function and embryonic development, including driving epithelial-mesenchymal transition. Several aspects of ZEB1 function can be regulated by its functional interactions with noncoding RNA types, namely microRNAs (miRNAs) and long noncoding RNAs (lncRNAs). Increasing evidence indicates that ZEB1 importantly influences cancer initiation, tumor progression, metastasis, and resistance to treatment. Cancer is the main disease-related cause of death in children and adolescents. Although the role of ZEB1 in pediatric cancer is still poorly understood, emerging findings have shown that it is expressed and regulates childhood solid tumors including osteosarcoma, retinoblastoma, neuroblastoma, and central nervous system tumors. Here, we review the evidence supporting a role for ZEB1, and its interplays with miRNAs and lncRNAs, in pediatric cancers.

Histone Deacetylase Inhibitors in Pediatric Brain Cancers: Biological Activities and Therapeutic Potential.

Brain cancers are the leading cause of cancer-related deaths in children. Biological changes in these tumors likely include epigenetic deregulation during embryonal development of the nervous system. Histone acetylation is one of the most widely investigated epigenetic processes, and histone deacetylase inhibitors (HDACis) are increasingly important candidate treatments in many cancer types. Here, we review advances in our understanding of how HDACis display antitumor effects in experimental models of specific pediatric brain tumor types, i.e., medulloblastoma (MB), ependymoma (EPN), pediatric high-grade gliomas (HGGs), and rhabdoid and atypical teratoid/rhabdoid tumors (ATRTs). We also discuss clinical perspectives for the use of HDACis in the treatment of pediatric brain tumors.

Fingolimod (FTY720) reduces viability and survival and increases histone H3 acetylation in medulloblastoma cells.

Histone deacetylase inhibitors (HDACis) are epigenetic agents that display antitumor activities in experimental medulloblastoma (MB). Fingolimod (FTY720), an immunosuppressant agent currently used in the treatment of multiple sclerosis, also has anticancer actions and can act as an HDACi. Here we examined whether fingolimod can inhibit human MB cell viability and survival, and if the effects are accompanied by increased histone acetylation. D283 and DAOY MB cells were treated with different doses of fingolimod. Cell viability was assessed by cell counting in a hemocytometer, and cell survival was analyzed with a colony formation assay. Histone H3 acetylation was measured with an enzyme-linked immunosorbent assay (ELISA). Fingolimod at 7.5 or 10 µM, but not at 5 µM, induced a significant reduction in cell viability in D283 and DAOY cultures, and similar results were observed for inhibition of cell survival. In both cell lines, fingolimod also led to a significant increase in the levels of acetylated H3. These findings provide preliminary evidence indicating that fingolimod induces antitumor activities in MB, possibly through a mechanism which increases H3 histone acetylation.

Viability of D283 medulloblastoma cells treated with a histone deacetylase inhibitor combined with bombesin receptor antagonists.

PURPOSE: Medulloblastoma (MB) comprises four distinct molecular subgroups, and survival remains particularly poor in patients with Group 3 tumors. Mutations and copy number variations result in altered epigenetic regulation of gene expression in Group 3 MB. Histone deacetylase inhibitors (HDACi) reduce proliferation, promote cell death and neuronal differentiation, and increase sensitivity to radiation and chemotherapy in experimental MB. Bombesin receptor antagonists potentiate the antiproliferative effects of HDACi in lung cancer cells and show promise as experimental therapies for several human cancers. Here, we examined the viability of D283 cells, which belong to Group 3 MB, treated with an HDACi alone or combined with bombesin receptor antagonists. METHODS: D283 MB cells were treated with different doses of the HDACi sodium butyrate (NaB), the neuromedin B receptor (NMBR) antagonist BIM-23127, the gastrin releasing peptide receptor (GRPR) antagonist RC-3095, or combinations of NaB with each receptor antagonist. Cell viability was examined by cell counting. RESULTS: NaB alone or combined with receptor antagonists reduced cell viability at all doses tested. BIM-23127 alone did not affect cell viability, whereas RC-3095 at an intermediate dose significantly increased cell number. CONCLUSION: Although HDACi are promising agents to inhibit MB growth, the present results provide preliminary evidence that combining HDACi with bombesin receptor antagonists is not an effective strategy to improve the effects of HDACi against MB cells.