Imipridones affect tumor bioenergetics and promote cell lineage differentiation in diffuse midline gliomas

Abstract

Background Pediatric diffuse midline gliomas (DMGs) are incurable childhood cancers. The imipridone ONC201 has shown early clinical efficacy in a subset of DMGs. However, the anticancer mechanisms of ONC201 and its derivative ONC206 have not been fully described in DMGs. Methods DMG models including primary human in vitro (n=18), and in vivo (murine and zebrafish) models, and patient (n=20) frozen and FFPE specimens were used. Drug-target engagement was evaluated using in silico ChemPLP and in vitro thermal shift assay. Drug toxicity and neurotoxicity were assessed in zebrafish models. Seahorse XF Cell Mito Stress Test, MitoSOX and TMRM assays, and electron microscopy imaging were used to assess metabolic signatures. Cell lineage differentiation and drug-altered pathways were defined using bulk and single cell RNA-seq. Results ONC201 and ONC206 reduce viability of DMG cells in nM concentrations and extend survival of DMG PDX models (ONC201: 117 days, p=0.01; ONC206: 113 days, p=001). ONC206 is 10X more potent than ONC201 in vitro and combination treatment was the most efficacious at prolonging survival in vivo (125 days, p=0.02). Thermal shift assay confirmed that both drugs bind to ClpP, with ONC206 exhibiting a higher binding affinity as assessed by in silico ChemPLP. ClpP activation by both drugs results in impaired tumor cell metabolism, mitochondrial damage, ROS production, activation of integrative stress response and apoptosis in vitro and in vivo. Strikingly, imipridone treatment triggered a lineage shift from a proliferative, oligodendrocyte precursor-like state to a mature, astrocyte-like state. Conclusion Targeting mitochondrial metabolism and ISR activation effectively impairs DMG tumorigenicity. These results supported initiation of a phase 1 pediatric clinical trial (PNOC023, NCT04732065).

Targeting Mitochondria with ClpP Agonists as a Novel Therapeutic Opportunity in Breast Cancer

“…Later, ONC206 and ONC212 were developed by Chimerix, Inc. ( , accessed on 2 January 2023) as more potent imipridones compared with ONC201. Studies confirmed that these imipridones impair OxPhos, induce mitochondrial damage, ROS, and ISR [ 271 , 292 ]. ONC201 has been shown to penetrate the brain-blood barrier [ 284 ].…”

Pediatric Diffuse Midline Gliomas: An Unfinished Puzzle

“…A second patient achieved an 18-month PFS, and she is still on treatment. Moreover, the synergy of ONC201 in combination with epigenetic modulators targeting H3K27M (such as vorinostat), or ONC206, a more recent analog, was demonstrated to be effective in several preclinical data [ 98 , 99 ]. Nowadays, four-phase I/II clinical trials with ONC201 are recruiting for patients with H3K27-altered gliomas, one of them specific to the pediatric population (NCT03416530).…”

One Host-Multiple Applications: Zebrafish (Danio rerio) as Promising Model for Studying Human Cancers and Pathogenic Diseases

“…Pro-angiogenic and invasive behaviors were observed 48 h after injection [ 22 ]. Other zPDX were described for a blood cancer patient with leukemia cells [ 23 ], human umbilical cord blood and human leukemia bone marrow samples [ 24 ], non-small cell lung cancer [ 25 ], pediatric diffuse midline gliomas [ 26 ], rhabdoid tumors, which is a pediatric tumor with very poor prognosis [ 27 ], and pancreatic [ 28 ] or human colon cancer [ 29 ]. The model obtained through patient-derived cells transplantation into the same organ or part of the ZF body is called orthotropic and it has been performed for brain tumor [ 30 ] or glioblastoma injection into the ZF’s midbrain [ 31 , 32 ].…”

“…The inhibition of the tail metastasis of SGC-7901 cells was observed after treatment of all drugs together or separately [ 103 ]. In vivo analysis of the drug toxicity and neurotoxicity of ONC206 and ONC201 in pediatric diffuse midline gliomas (DMGs) proved that the combination of these two drugs was the most effective in prolonging survival [ 26 ]. A new, interesting direction in cancer research is testing the anticancer potential of newly discovered plant compounds.…”