High-risk neuroblastoma: where do we go?

Suppression of endoplasmic reticulum stress-dependent autophagy enhances cynaropicrin-induced apoptosis via attenuation of the P62/Keap1/Nrf2 pathways in neuroblastoma

Autophagy has dual roles in cancer, resulting in cellular adaptation to promote either cell survival or cell death. Modulating autophagy can enhance the cytotoxicity of many chemotherapeutic and targeted drugs and is increasingly considered to be a promising cancer treatment approach. Cynaropicrin (CYN) is a natural compound that was isolated from an edible plant (artichoke). Previous studies have shown that CYN exhibits antitumor effects in several cancer cell lines. However, it anticancer effects against neuroblastoma (NB) and the underlying mechanisms have not yet been investigated. More specifically, the regulation of autophagy in NB cells by CYN has never been reported before. In this study, we demonstrated that CYN induced apoptosis and protective autophagy. Further mechanistic studies suggested that ER stress-induced autophagy inhibited apoptosis by activating the p62/Keap1/Nrf2 pathways. Finally, in vivo data showed that CYN inhibited tumour growth in xenografted nude mice. Overall, our findings suggested that CYN may be a promising candidate for the treatment of NB, and the combination of pharmacological inhibitors of autophagy may hold novel therapeutic potential for the treatment of NB. Our paper will contribute to the rational utility and pharmacological studies of CYN in future anticancer research.

Nanomedicines and cell-based therapies for embryonal tumors of the nervous system

Embryonal tumors of the nervous system are neoplasms predominantly affecting the pediatric population. Among the most common and aggressive ones are neuroblastoma (NB) and medulloblastoma (MB). NB is a sympathetic nervous system tumor, which is the most frequent extracranial solid pediatric cancer, usually detected in children under two. MB originates in the cerebellum and is one of the most lethal brain tumors in early childhood. Their tumorigenesis presents some similarities and both tumors often have treatment resistances and poor prognosis. High-risk (HR) patients require high dose chemotherapy cocktails associated with acute and long-term toxicities. Nanomedicine and cell therapy arise as potential solutions to improve the prognosis and quality of life of children suffering from these tumors. Indeed, nanomedicines have been demonstrated to efficiently reduce drug toxicity and improve drug efficacy. Moreover, these systems have been extensively studied in cancer research over the last few decades and an increasing number of anticancer nanocarriers for adult cancer treatment has reached the clinic. Among cell-based strategies, the clinically most advanced approach is chimeric-antigen receptor (CAR) T therapy for both pathologies, which is currently under investigation in phase I/II clinical trials. However, pediatric drug research is especially hampered due not only to ethical issues but also to the lack of efficient pre-clinical models and the inadequate design of clinical trials. This review provides an update on progress in the treatment of the main embryonal tumors of the nervous system using nanotechnology and cell-based therapies and discusses key issues behind the gap between preclinical studies and clinical trials in this specific area. Some directions to improve their translation into clinical practice and foster their development are also provided.

Immunohistochemical staining of phosphorylated-ERK in post-chemotherapeutic samples is a potential predictor of the prognosis of neuroblastoma

PURPOSE

The majority of relapsed neuroblastomas have mitogen-activated protein kinase (MAPK) pathway activating mutations. We previously showed the in vitro and in vivo anti-tumor effects of MAPK/ERK kinase (MEK) inhibitors in MAPK-activated neuroblastoma. We herein assessed the correlation between MAPK activation and the prognosis in neuroblastoma patients using phosphorylated extra-cellular signal-regulated kinase (pERK) immunohistochemistry to establish the protocol for the clinical administration of MEK inhibitors.

METHODS

Neuroblastoma samples from patients treated in our hospital were immunostained with pERK. The clinical outcomes were retrospectively collected from medical records. The correlation between pERK positivity and the prognosis was analyzed.

RESULTS

Regarding pre-chemotherapeutic specimens, there were no differences in the pERK status between tumors with a good and bad prognosis in both the nuclei and cytoplasm. Regarding post-chemotherapeutic specimens, one of eight tumors with a good prognosis and four of six tumors with a poor prognosis showed pERK-positive nuclear staining (p = 0.0909) and five of eight tumors with a good prognosis and four of six tumors with a poor prognosis showed pERK-positive cytoplasmic staining (p > 0.9999).

CONCLUSION

These findings suggested post-chemotherapeutic-not pre-chemotherapeutic-nuclear pERK-positive neuroblastoma tends to be associated with a poor prognosis and may be a potential therapeutic target for MEK inhibitor treatment.

Anti-tumor effect of Huaier extract against neuroblastoma cells in vitro

Huaier extract, the main active constituent proteoglycan, has anti-tumor activity in various experimental and clinical settings. However, the potential anti-neuroblastoma and associated mechanisms have not been investigated. Therefore, in this study, we aimed to elucidate the potential role of Huaier extract in 3 human neuroblastoma cell lines. Our study demonstrated that incubation with Huaier extract resulted in a marked decrease in cell viability in a dose-dependent manner. Huaier extract induced cell cycle arrest at G0/G1 phase in neuroblastoma and decreased the cell cycle related protein expression of cyclin D3. Western blotting analysis also showed that Huaier extract induced neuroblastoma cell apoptosis and autophagy. Signaling analysis indicated that Huaier extract suppressed the MEK/ERK and mTOR signaling pathways simultaneously. In conclusion, we verify that Huaier extract causes cell proliferation inhibition, apoptosis, autophagy, and cell cycle arrest in G0/G1 phase via MEK/ERK and mTOR signaling. Huaier extract may act as a complementary agent for treating neuroblastoma.

Integrated Microarray to Identify the Hub miRNAs and Constructed miRNA-mRNA Network in Neuroblastoma Via Bioinformatics Analysis

Neuroblastomas (NB) are childhood malignant tumors originating in the sympathetic nervous system. MicroRNAs (miRNAs) play an essential regulatory role in tumorigenesis and development. In this study, NB miRNA and mRNA expression profile data in the Gene Expression Omnibus database were used to screen for differentially expressed miRNAs (DEMs) and genes (DEGs). We used the miRTarBase and miRSystem databases to predict the target genes of the DEMs, and we selected target genes that overlapped with the DEGs as candidate genes for further study. Annotations, visualization, and the DAVID database were used to perform Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis on the candidate genes. Additionally, the protein-protein interaction (PPI) network and miRNA-mRNA regulatory network were constructed and visualized using the STRING database and Cytoscape, and the hub modules were analyzed for function and pathway enrichment using the DAVID database and BiNGO plug-in. 107 DEMs and 1139 DEGs were identified from the miRNA and mRNA chips, respectively. 4390 overlapping target genes were identified using the two databases, and 405 candidate genes which intersected with the DEGs were selected. These candidate genes were enriched in 363 GO terms and 24 KEGG pathways. By constructing a PPI network and a miRNA-mRNA regulatory network, three hub miRNAs (hsa-miR-30e-5p, hsa-miR-15a, and hsa-miR-16) were identified. The target genes of the hub miRNAs were significantly enriched in the following pathways: microRNAs in cancer, the PI3K-Akt signaling pathway, pathways in cancer, the p53 signaling pathway, and the cell cycle. In summary, our results have identified candidate genes and pathways related to the underlying molecular mechanism of NB. These findings provide a new perspective for NB research and treatment.