The Splicing Factor RBM17 Supports Leukemia Stem Cell Self-Renewal
Notice bibliographique
Résumé
Background: Acute myeloid leukemia (AML) is thought to be sustained by sub-populations of leukemia stem cells (LSCs), which possess the capacity for self-renewal and differentiation and are believed to be responsible for disease initiation, relapse and chemoresistance. There is therefore an urgent need to develop therapies that target the LSC population to achieve effective AML treatment. To date there has been limited success in this endeavor, highlighting the importance of gaining a more comprehensive understanding of the mechanistic elements that underpin LSC function. Aberrant alternative splicing is recognized as a key driver of cancer. In the context of AML, genome-wide sequencing studies have shown that approximately one third of genes are differentially spliced in primitive CD34+ cells in AML patients compared to those obtained from normal controls. In particular, LSCs also have a unique splicing profile when compared to normal aging HSCs, underscoring the importance of understanding the mechanistic controls of aberrant splicing in LSC function. Results: Previous studies examining the link between aberrant splicing and AML focused on spliceosome genes with somatic mutations in AML patients. To examine mechanisms that mediate aberrant alternative splicing in LSC beyond splicing factor mutations, we performed a data-mining survey of 203 known mRNA splicing factors. Strikingly, RNA-binding motif protein 17 (RBM17) is the only splicing factor that is both strongly linked to poor AML prognosis and significantly elevated in LSC-enriched subsets of primary AML samples based on a recent study of 78 AML samples with normal karyotype. RBM17 has been implicated in regulating alternative splicing and cancer chemotherapy resistance. However, its function in AML or LSCs is not known. From our studies, we found that the level of RBM17 protein is elevated in the phenotypically primitive subsets of primary AML samples (n=8, RBM17+%: 67.42% in CD34+ versus 34.66% in CD34-fractions). Depletion of RBM17 with shRNAs in 3 human primary AML samples resulted in reduced colony formation compared to shScramble controls. More importantly, knockdown of RBM17 in a primary AML sample greatly impeded AML engraftment in immune-deficient mice (mean of 0.89 control versus mean of 0.1671 and 0.3171 shRNAs), suggesting that RBM17 is required for the stem and progenitor potential of AML and maintenance of LSC populations. Intriguingly, in contrast to the situation for the malignant hierarchy, the level of RBM17 in normal HSCs is lower than that in more committed cell populations in the normal hematopoietic system. To determine if RBM17 plays different roles in malignant LSC and normal hematopoietic stem and progenitor cells (HSPCs), we depleted RBM17 with shRNAs in human cord blood (CB) derived CD34+ HSPCs, and found RBM17 knockdown had negligible adverse impact on both CB total colony and primitive GEMM colony outputs and yielded no increase in apoptosis, indicating no defects were apparent to primitive cells of CB as read out in vitro. To uncover the molecular mechanisms underlying the role of RBM17 in LSC functions, we preformed RBM17 eCLIP-seq in the K562 and HL60 human leukemic cell lines. We then cross-analyzed the CLIP-seq datasets with a published ENCODE RNA-seq dataset (RBM17 knockdown in K562 cells), where we found RBM17 directly binds to transcripts of stem cell program-related genes and regulates the splicing of these genes, including MADD (MAP kinase activating death domain) and MRPS18C (mitochondrial ribosomal protein S18C). We further demonstrated that the splicing patterns of MADD and MRPS18C are mediated by RBM17 in primary AML samples. In our ongoing functional validation experiments, isoform-specific knockdown of MADD or MRPS18C splice variants downstream of RBM17 impeded colony forming capacity and induced myeloid differentiation in the MOLM13 AML cell line. These results suggest that RBM17-mediated splicing events impact primitive cell function in AML. Conclusion: We have identified RBM17 as a novel LSC-regulating factor, plays an important role in maintaining AML LSC function through regulating the alternative splicing of stem cell program-related genes. The potential LSC-selective role for RBM17, along with its downstream splicing events, represent promising putative therapeutic targets whose modulation could offer attractive therapeutic windows in AML treatment. Disclosures No relevant conflicts of interest to declare.
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 machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,001 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 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) | 0,002 | 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 source (Gemma direct ou Codex distillé), 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 ».