Identifying Stress Granules As Determinants of Leukemia Stem Cell Maintenance and Stress Adaptation
Notice bibliographique
Résumé
The development of novel leukemic stem cell (LSC)-targeted therapeutics, which spare hematopoietic stem cells (HSC), is an urgent goal towards reducing the high, LSC-driven, relapse rates in acute myeloid leukemia (AML) patients. Towards elucidating key post-transcriptional networks underlying LSC maintenance we previously performed an in vivo pooled CRISPR dropout screen targeting 128 RNA binding proteins (RBPs) highly expressed in AML LSCs while having low expression in HSCs. This screen highlighted 12 RBPs crucial for murine AML LSC-mediated leukemic growth, of which there was a significant enrichment of stress granule (SG) RBPs. Further, gene set enrichment analysis shows the SG proteome is enriched in human AML LSCs vs non-LSCs while normal HSCs have reduced SG RBP expression relative to multipotent progenitor cells. SGs are dynamic biomolecular condensates, composed of ribonucleoprotein complexes, which may form as a protective mechanism against a variety of stress conditions. SGs are gaining increasing attention as contributors to cancer metastasis and chemoresistance, but their role in LSCs is virtually unexplored. The intriguing enrichment of SG RBPs in our screen hints at a larger role for SGs in LSC maintenance and/or stress resistance. To address this, we focused on the core SG nucleation RBP, G3BP1, a molecular switch that guides SG assembly. Fluorescence microscopy was first performed to describe SG dynamics in leukemia vs primitive normal cells where interestingly, a subset of patient AML cells contained G3BP1 SGs in the absence of added stress. In contrast, primitive healthy murine stem cells had reduced heat shock-induced SG formation in comparison to downstream normal progenitors. A series of shG3BP1 knockdown experiments performed in human leukemia cell lines and patient AML specimens demonstrated that shG3BP1-transduced cells showed increased apoptosis and differentiation and reduced colony forming capacity and competition in vitro compared to control cells. The same set of assays showed minimal impact of SG impairment to healthy umbilical cord blood cells. Importantly, in vivo xenotransplantation demonstrated that LSCs with G3BP1 knocked down were significantly compromised in their capacity to generate leukemic grafts whereas normal HSCs assessed in a similar manner display much less G3BP1 dependency. Towards determination of the SG mechanisms essential for bulk AML and LSC regulation, we performed matched RNA-sequencing and proteomics in G3BP1 knocked down AML cells as well as BioID in AML cell lines, primary patient AML cell subsets, and healthy hematopoietic cells to allow for the uncovering of an AML specific SG proteome. These analyses highlighted numerous potential SG mechanisms of cancer cell stress resistance and/or stem cell regulatory processes including sequestration of apoptotic factors and oncogenic signalling pathways. Of note, RNA-seq and proteomics in SG impaired shG3BP1 leukemia cells showed both a negative enrichment of the SG proteome and LSC signature as well as a positive enrichment of the innate immune response. Interestingly, our BioID uncovered that the AML specific SG proteome is also enriched for positive regulation of RIG-I signaling pathway (GO: Biological Process). Together this data suggests SGs play a protective role through the downregulation of overactive innate immune signalling in AML. Work using optimized small input approaches to map SG RNA and protein interactomes in LSCs vs HSCs to confirm similar regulatory relationships as well as identify LSC-context specific ones is ongoing. Overall, these results elucidate SGs as key AML LSC stress adaptive regulatory networks and highlights them as novel targets for consideration in AML therapeutics.
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 | 0,000 |
| 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) | 0,001 | 0,000 |
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 ».