A Novel MYCN-Specific Antigene Oligonucleotide Deregulates Mitochondria and Inhibits Tumor Growth in MYCN-Amplified Neuroblastoma

Abstract

Approximately half of high-risk neuroblastoma is characterized by MYCN amplification. N-Myc promotes tumor progression by inducing cell growth and inhibiting differentiation. MYCN has also been shown to play an active role in mitochondrial metabolism, but this relationship is not well understood. Although N-Myc is a known driver of the disease, it remains a target for which no therapeutic drug exists. Here, we evaluated a novel MYCN-specific antigene PNA oligonucleotide (BGA002) in MYCN-amplified (MNA) or MYCNexpressing neuroblastoma and investigated the mechanism of its antitumor activity. MYCN mRNA and cell viability were reduced in a broad set of neuroblastoma cell lines following BGA002 treatment. Furthermore, BGA002 decreased N-Myc protein levels and apoptosis in MNA neuroblastoma. Analysis of gene expression data from patients with neuroblastoma revealed that MYCN was associated with increased reactive oxygen species (ROS), downregulated mitophagy, and poor prognosis. Inhibition of MYCN caused profound mitochon-drial damage in MNA neuroblastoma cells through downregulation of the mitochondrial molecular chaperone TRAP1, which subsequently increased ROS. Correspondingly, inhibition of MYCN reactivated mitophagy. Systemic administration of BGA002 downregulated N-Myc and TRAP1, with a concomitant decrease in MNA neuroblastoma xenograft tumor weight. In conclusion, this study highlights the role of N-Myc in blocking mitophagy in neuroblastoma and in conferring protection to ROS in mitochondria through upregulation of TRAP1. BGA002 is a potently improved MYCN-specific antigene oligonucleotide that reverts N-Myc-dysregulated mitochondrial pathways, leading to loss of the protective effect of N-Myc against mitochondrial ROS.Significance: A second generation antigene peptide oligonucleotide targeting MYCN induces mitochondrial damage and inhibits growth of MYCN-amplified neuroblastoma cells.

Serial Assessment of Circulating T lymphocyte Phenotype and Receptor Repertoire During Treatment of Non-Muscle Invasive Bladder Cancer with Adoptive T Cell Immunotherapy

“…Previously, we observed that increases in these suppressor cell types were associated with worse outcome in breast cancer patients and were predictive of cancer cell release into the blood stream [23]. In the current study, when suppressor cell subtypes increased, circulating tumor DNA mutations (in genes with relevance for tumor aggressiveness [24][25][26][27]) appeared and after delivery of DC-CIK, these suppressor cells decreased and the mutations disappeared. This suggests that the DC-CIK were responsible for sustaining the complete remission by modulating suppressor populations and/or by direct anti-tumor effects.…”

“…The patient received two cycles of DC/CIK infusions and these mutations disappeared. We have some conviction data to support the phenomenon that T suppressor cells elevated from the peripheral blood was predictor to clinical tumor progression, little knew that occurrence of SETD2 and NOTCH4 mutation were risen from tumor progression or accompanying transit events followed by DC/CIK immunotherapy as some publications have revelations SETD2, MYCN and NOTCH4 could induced drug resistance and initiation of cancer progression [25,26].. Nether less the subsequently new mutations in the FAT1 gene accompanied an increase in CD8 + /CD28 − to 19.6% which decreased to 15.2% after T cell infusion (Fig. 3) coincident with loss of the mutation in FAT1.…”

Transcriptomic Analyses of MYCN-Regulated Genes in Anaplastic Wilms’ Tumour Cell Lines Reveals Oncogenic Pathways and Potential Therapeutic Vulnerabilities

“…Similarly, several MYC target gene sets were downregulated in both cell-lines, indicating that MYCN drives canonical MYC target genes in WT ( Figure S4B), like the curated MYC gene set in Hallmark [39]. Further, genes encoding mitochondrial proteins that were recently shown to be regulated by MYCN [40] were also downregulated, emphasizing the role of MYCN in activating mitochondrial function genes in WT. Genes encoding for proteins with roles in "RNA export from nucleus" were downregulated, which may affect pre-miRNA transport and the miRNA pool in the cytoplasm, while those participating in "Unfolded protein response" were upregulated, suggestive of endoplasmic reticulum stress in the MYCN-depleted cells ( Figure S4C).…”

MYCN Drives a Tumor Immunosuppressive Environment Which Impacts Survival in Neuroblastoma

“…MYCN is a transcription factor member of the MYC proto-oncogene family involved in nervous system development during embryogenesis ( 1 ). MYCN regulates different fundamental cellular processes including cell cycle, apoptosis, mitochondria dysfunction, and metabolism ( 2 , 3 ). Indeed, MYCN expression deregulation is linked to a wide range of human tumors ( 4 ).…”

“…Thus, different other approaches have been developed to downregulate N-Myc or its associated pathways ( 8 ). Among these strategies, anti- MYCN antigene oligonucleotide PNA showed the ability to specifically block MYCN expression in a sustained way ( 3 , 9 , 10 ), resulting in an anti-cancer effect.…”