Neuro Oncol. 2024 Mar 30:noae066. doi: 10.1093/neuonc/noae066. Online ahead of print.

ABSTRACT

BACKGROUND: Pediatric high-grade gliomas (pHGGs), including diffuse midline gliomas (DMGs), are aggressive pediatric tumors with one of the poorest prognoses. Delta-24-RGD and ONC201 have shown promising efficacy as single agents for these tumors. However, the combination of both agents has not been evaluated.

METHODS: The production of functional viruses was assessed by immunoblotting and replication assays. The antitumor effect was evaluated in a panel of human and murine pHGG and DMG cell lines. RNAseq, the seahorse stress test, mitochondrial DNA content, and γH2A.X immunofluorescence were used to perform mechanistic studies. Mouse models of both diseases were used to assess the efficacy of the combination in vivo. The tumor immune microenvironment was evaluated using flow cytometry, RNAseq and multiplexed immunofluorescence staining.

RESULTS: The Delta-24-RGD/ONC201 combination did not affect the virus replication capability in human pHGG and DMG models in vitro. Cytotoxicity analysis showed that the combination treatment was either synergistic or additive. Mechanistically, the combination treatment increased nuclear DNA damage and maintained the metabolic perturbation and mitochondrial damage caused by each agent alone. Delta-24-RGD/ONC201 cotreatment extended the overall survival of mice implanted with human and murine pHGG and DMG cells, independent of H3 mutation status and location. Finally, combination treatment in murine DMG models revealed a reshaping of the tumor microenvironment to a proinflammatory phenotype.

CONCLUSIONS: The Delta-24-RGD/ONC201 combination improved the efficacy compared to each agent alone in in vitro and in vivo models by potentiating nuclear DNA damage and in turn improving the antitumor (immune) response to each agent alone.

PMID:38554031 | DOI:10.1093/neuonc/noae066

Neurooncol Adv. 2024 Mar 16;6(1):vdae029. doi: 10.1093/noajnl/vdae029. eCollection 2024 Jan-Dec.

ABSTRACT

BACKGROUND: Diffuse intrinsic pontine gliomas (DIPGs) pose a significant challenge as a highly aggressive and currently incurable form of pediatric brain cancer, necessitating the development of novel therapeutic strategies. Omacetaxine, an FDA-approved protein synthesis inhibitor for treating certain hematological malignancies, was investigated for its potential antitumor effects against preclinical DIPG models.

METHODS: We employed primary DIPG cultures to study omacetaxine's cytotoxicity and its impact on colony formation. Annexin V staining and flow cytometry assessed apoptosis. Wound healing assays evaluated migration, while western blotting determined inhibition of oncogenic proteins. We tested omacetaxine's therapeutic efficacy in an orthotopic DIPG model and assessed brain penetration using mass spectrometry.

RESULTS: We found a pronounced cytotoxic activity of omacetaxine against DIPG neurospheres, with low IC₅₀ values of approximately 20 nM. Omacetaxine exerted its anti-proliferative effect by inhibiting protein synthesis and the induction of apoptotic pathways, evidenced by significant elevated levels of cleaved caspase 3 and cleaved PARP, both key markers of apoptosis. Omacetaxine effectively targeted oncogenic players such as PDGFRα and PI3K without additional effects on the mTOR signaling pathway. Furthermore, our study revealed the inhibitory effects of omacetaxine on cell migration, and a significant reduction in integrin/FAK signaling, which plays a crucial role in tumor progression and metastasis.

CONCLUSIONS: Despite these promising in vitro effects, omacetaxine's efficacy in an orthotopic DIPG model was limited due to inadequate penetration across the blood-brain barrier. As such, further research and advancements are crucial to improve the drug's brain penetration, thus enhancing its overall therapeutic potential.

PMID:38550394 | PMC:PMC10976909 | DOI:10.1093/noajnl/vdae029

2024 May 10. PDQ Cancer Information Summaries [Internet]. Bethesda (MD): National Cancer Institute (US); 2002–.

ABSTRACT

This PDQ cancer information summary has current information about the treatment of diffuse intrinsic pontine glioma. It is meant to inform and help patients, families, and caregivers. It does not give formal guidelines or recommendations for making decisions about health care.

Editorial Boards write the PDQ cancer information summaries and keep them up to date. These Boards are made up of experts in cancer treatment and other specialties related to cancer. The summaries are reviewed regularly, and changes are made when there is new information. The date on each summary ("Date Last Modified") is the date of the most recent change. The information in this patient summary was taken from the health professional version, which is reviewed regularly and updated as needed, by the PDQ Pediatric Treatment Editorial Board.

PMID:38377270 | Bookshelf:NBK600525