P465: N-MYRISTOYLATION INHIBITION ABROGATES OXIDATIVE PHOSPHORYLATION TO TARGET ACUTE MYELOID LEUKEMIA STEM CELLS
Notice bibliographique
Résumé
Background: Protein N-myristoylation is the linkage of the fatty acid myristate to the N-terminus of a protein. Catalyzed by two human enzymes – N-myristoyltransferase 1 & 2 (NMT1/2) – this modification alters the stability, localization, complex association, and function of proteins. Up to 600 myristoylated human proteoforms impact a wide variety of processes including signal transduction, cytoskeletal rearrangement, apoptosis and metabolism. We reported the importance of myristoylation of Src-family kinases (SFKs) for B-cell receptor signaling in B-cell lymphomas; treating cells with first-in-class myristoylation inhibitor PCLX-001 rapidly led to cell death. In acute myeloid leukemia (AML), two frequently mutated receptor tyrosine kinases, FLT3 and c-Kit, rely upon SFKs for signal transduction, leading us to explore the therapeutic potential of PCLX-001 in AML. A challenge in treating AML is leukemic stem cells (LSCs); a rare, self-renewing population which frequently survives therapy, expanding to re-establish disease. The heterogeneity of LSCs adds further complexity as therapies result in the enrichment of drug-resistant clones leading to refractory disease. New AML therapies thus require targeting LSCs. Recent reports showed that LSCs have a relatively inflexible metabolism, rely on oxidative phosphorylation (OXPHOS) for survival and that inhibition of OXPHOS led to LSCs killing. Aims: To demonstrate the efficacy of myristoylation inhibitor PCLX-001 in AML, elucidate its mechanism of action, and evaluate its ability to target LSCs. Methods: Efficacy of PCLX-001 against AML cell lines in comparison to PBMCs and lymphocytes from healthy individuals was determined by CellTiterBlue viability assay. SFK proteins, SFK activation, ER stress, and apoptosis induction were examined by western blotting. PCLX-001 efficacy against LSCs was examined using OCI-AML-22 cell model by assaying viability of LSC-enriched fractions. In vivo efficacy was determined using tail vein and intra-femoral murine xenografts of primary patient samples; mice were treated with PCLX-001 and blood or marrow collected for flow cytometric analysis for engrafted cells. Seahorse and Resipher platforms were used to measure oxygen consumption rates (OCR) in AML cell lines. Levels of myristoylated mitochondrial complex I proteins NDUFAF4 and NDUFB7 were measured by western blotting. Levels of total complex I and its in-gel activity were measured after blue native gel electrophoresis of isolated mitochondria. Results: PCLX-001 treatment induced cell death in AML cell lines at concentrations that spared healthy PBMCs and lymphocytes. PCLX-001 treatment resulted in loss of total SFKs and SFK phosphorylation leading to an increase in ER stress (Bip protein) and apoptosis (caspase 3 cleavage). In OCI-AML-22, LSC-enriched population viability was reduced in response to PCLX-001 treatment after 48 hours, and bulk populations after 72 hours. In vivo, PCLX-001 treatment reduced the numbers of AML cells circulating in the blood and marrow. PCLX-001 produced a dose-dependent reduction in OCR in treated AML cells, and a corresponding loss of NDUFAF4 and NDUFB7 proteins, and complex I assembly and activity. Summary/Conclusion: We demonstrate PCLX-001 kills bulk leukemic cells and LSCs in vitro and in vivo by disrupting the function of key myristoylated proteins. While PCLX-001 is currently undergoing clinical evaluation in B-cell lymphoma and solid tumours, these results warrant clinical evaluation in AML with trials scheduled to start spring 2023. Keywords: Acute myeloid leukemia, Cancer, Src kinase, Mitochondria
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».