Overexpression of Mir-21-5p Induces Apoptosis and Cell Cycle Arrest By Down-Regulating SKP2 and Overcomes Bortezomib Resistance in Multiple Myeloma
Notice bibliographique
Résumé
High expression of SKP2 (S-Phase Kinase Associated Protein 2) is associated with tumor cell growth and drug resistance in many solid tumors and hematological malignancies. However, the role of SKP2 in drug resistance/ relapse of multiple myeloma (MM) patients has not been fully investigated. To this end, we first analyzed two publicly accessible datasets (GSE6477, GSE9782) which demonstrated that relapsed MM patients showed higher expression of SKP2 compared to newly diagnosed patients (p=0.02). Furthermore, high expression of SKP2 was correlated with shorter overall survival compared to newly diagnosed MM patients with low SKP2 expression (p=0.0002). To investigate whether miRNAs could play a role in the dysregulation of SKP2 in MM, we exploited several miRNA-target prediction algorithms (Targetscan, miRDB, microT-CDS) to generate a selective miRNA library for subsequent screening. Over all, the screening results displayed 59 miRNA candidates predicated to target SKP2, 9 miRNAs were commonly identified by all three algorithms. Among these, miR-21-5p showed the highest potential binding score for SKP2 and was found to be in an inverse correlation with SKP2 in MM patient dataset (GSE16558). To address whether miR-21-5p/SKP2 axis may play a role in drug resistance in MM, we used two drug resistant MM cell lines (RPMI-8226R5 and MM.1R) to analyze the basal expression of SKP2 and miR-21-5p compared with that in their parental lines (RPMI-8226 and MM.1S, respectively). It turned out that the resistant MM cells displayed low expression of miR-21-5p and high expression of SKP2 whereas the parental lines showed the opposite pattern. Moreover, overexpression of miR-21-5p in both MM drug resistant cell lines significantly reduced both mRNA and protein levels of SKP2 further supporting that SKP2 could be a target of miR-21-5p. SKP2 mediates the ubiquitination of cyclin kinase inhibitor p27Kip1, a central negative regulator of cell cycle. In line with this, our immunoblot analysis confirmed that high SKP2 expressing drug resistant MM cells showed a low level of p27Kip1protein and low SKP2 expressing MM parental lines showed a high level of p27kip1 protein. To investigate the functional effects of miR-21-5p overexpression, we first performed FACS to determine if this overexpression would modulate cell cycle regulation of drug resistant MM cells. miR-21-5p overexpression increased in the proportion of cells at G1/G0 phase (RPMI-8226R5: 41.6 % to 59.1%, MM.1R: 19.5 % to 39.4%), decreased in the proportion of cells in S phase (RPMI-8226R5: 30.9 % to 25.5 %, MM.1R: 44.7 % to 32.2%) and G2/M phase (RPMI-8226R5: 15.5 % to 11.5 %, MM.1R: 27.6 % to22.4% ) compared with scrambled control. At the same time, immunoblot results showed that overexpression of miR-21-5p accumulated p27Kip1 and p21 (Cip1/Waf1), and suppressed CDK6 and Cyclin E cell cycle markers. Next, we examined the effect of miR-21-5p overexpression on cell proliferation and apoptosis in MM resistant cells using both MTT cytotoxicity assay and vital exclusion staining (trypan blue). In both assays, miR-21-5p mimics-transfected MM resistant cells showed significant reduction of cell viability and increase in apoptosis in a time-dependent manner compared with scrambled-transfected cells. Overexpression of miR-21-5p upregulated apoptotic markers: cleaved PARP-1, cleaved caspase-3, PUMA and BAX and down regulated anti-apoptotic markers: BCL-2 and survivin. Subsequently, efficacy of bortezomib (BTZ) was examined on miR-21-5p overexpressed MM resistant cells which were interestingly re-sensitized to BTZ in a dose- and time-dependent manner. In addition, our FACS experiment also confirmed that combination of BTZ and miR-21-5p mimics increased the percentage of annexin-V positive cells compared to scrambled and miR-21-5p mimics in the MM resistant cells. In conclusion, miR-21-5p is suppressed in MM resistant cells, which contributes to the drug resistance in MM through upregulation of SKP2. Overexpression of miR-21-5p induces apoptosis and cell cycle arrest in MM drug resistant cells by downregulating SKP2 gene expression and overcomes BTZ resistance in these cells. Our study provides a proof-of-concept that miR-21-5p could be utilized as a SKP2-targeting molecule which in combination with BTZ would be a promising therapeutic approach to overcome MM drug resistance. 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 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,001 |
| 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 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 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 ».