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

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 = .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 = .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 (ISR), 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 the initiation of two pediatric clinical trials (NCT05009992, NCT04732065).

Outcome of craniopharyngioma in children: long-term complications and quality of life.

Childhood craniopharyngiomas are histologically benign tumours arising from remnants of Rathke's pouch in the hypothalamic-pituitary region. The two common treatment approaches are primary total resection or limited resection followed by radiotherapy. To study the outcome after a primary surgical approach, we followed 25 consecutive patients (10 females, 15 males) under 16 years of age who were treated in a single institution with a management policy of radical tumour excision (mean age at diagnosis 9 years 2 months, SD 4 years 3 months; range 2 years 9 months to 15 years 11 months). Mean follow-up after primary surgery was 11 years 3 months (SD 7 years 7 months). Tumour control, and neurological, endocrine, and hypothalamic complications and their impact on health-related quality of life were assessed (medical follow-up, semi-structured interview, and questionnaires). Results of tumour control were generally good, however, local failure was observed in 6 of 25 patients, and severe late-treatment complications decreased quality of life for many long-time survivors. Endocrine deficiency occurred in 24/25, visual complications in 16/24, neurological complications in 8/24, obesity in 14/23, increased daytime sleepiness in 6/21, and significant school problems in 10/20. Patients with craniopharyngioma rated their health-related quality of life as considerably lower than healthy controls; the domains of social and emotional functioning were particularly affected. Parents' ratings were considerably lower than those of the patients. Poor functional outcome was associated with large tumours infiltrating or displacing the hypothalamus, the occurrence of hydrocephalus, and young age at diagnosis, but also with multiple operations due to tumour recurrence. Alternative treatment strategies should be considered, especially in very young patients with large tumours.