Integrin β7-Mediated Regulation of Multiple Myeloma Cell Adhesion, Migration and Survival.
Notice bibliographique
Résumé
Abstract Abstract 949 Background: Integrin β7 (ITGB7) mRNA is detected in primary myeloma (MM) cells and its presence was correlated with maf gene activation. However, little is known about the role ITGB7 plays in MM. Methods and results: We have determined the expression of ITGB7 by flow cytometry in a large library of human MM cell lines and found it to be universily expressed, albeit at different levels. Similarly ITGB7 mRNA was detected by qRT-PCR in 25/27 samples of primary MM CD138+ cells. In order to better investigate the role of ITGB7 in MM adhesion, migration and survival we performed a loss-of-function analysis using the shRNA lentivirus system. Lentiviral transduction particles with validated ITGB7 shRNA, were transduced into three different MM cell lines (MM1S, INA-6 and H929) establishing stable clones with silenced ITGB7. Using adhesion assays we have demonstrated that ITGB7silenced cells are 40-50% less adherent to fibronectin (FN), E-cadherin (E-CDH) and BMSCs coated plates when compared to ITGB7positive cells (scrambeled shRNA), confirming the role ITGB7 in MM cell adhesion to stromal elements. In a transwell migration assay, ITGB7 silencing abrogated MM cells migration in response to SDF-1 gradient implicating ITGB7 in MM cells migration. Next, we investigated whether ITGB7 conferred a survival benefit to MM cells. By MTT assay ITGB7silenced cell are more sensitive to the cytotoxic effect of Bortezomib and Melphalan when cultured on regular plate and/or in the presence of FN and E-CDH, suggesting a role for ITGB7 in conferring drug resistance to MM cells through cell-adhesion dependent and independent mechanisms. Mechanistic studies have shown that ITGB7silenced cells have reduced NF-kB activity with reduced NFkB-p65 binding to the related consensus sequence and decreased nuclear phospho-p65 translocation was confirmed by immunofluorescence staining. In ELISA based assay ITGB7silenced cells co-cultured with BMSCs produced less cytokines and growth factors (VEGF, IL-6, TNF, IL-1, SDF1α) compared to ITGB7positive/BMSCs co-cultures confirming the role of ITGB7 in mediating MM cells intereaction with BMSCs altering the cytokines and growth factors produced by stromal cells. In order to investigate the signalling pathways downstream of ITGB7, ITGB7positive and ITGB7silenced INA-6 and MM1S cells were added into human FN coated plates and total RNA extracted and submitted to gene array profiling using the U133 Plus 2.0 Array. Several NF-kB regulated genes (TNF-α2, syndecan 4, IL-6, IL-8, CDK-6, Max) were downregulated and pathway analysis (Ingenuity Systems Software) identified several MM relevant pathways to be modulated by ITGB7 silencing; among them p53, integrin, IGF-1, IL-6 and VEGF signaling as well as cell cycle, apoptosis and the Wnt/β-catenin signalling pathways. Based on the in vitro data, we next investigated in vivo the effect of ITGB7 silencing on engraftment and homing of MM to bone marrow (BM), using a human plasmacytoma xenograft scid mouse model. ITGB7silenced cells grew mainly locally at the subcutaneous implantation site with delayed engraftment into the BM while ITGB7positive cells homed mostly into the BM, as indicated by the number of human CD138+ cells counted on femoral BM sections (14% in ITGB7positive vs. 4% in ITGB7silenced). In addition, tumor vessels density within the xenografted tumors, as assessed by CD31 staining, was significantly reduced in ITGB7silenced compared to ITGB7positive tumors (CD31 target area %: 4.1 vs 7.7 respectively). Lastly using myeloma tissue microarray (TMA) we have correlated ITGB7 expression with a significantly worse survival outcomes post high dose therapy and stem cell transplantation with a mTTP of 0.9 years in ITGB7 positive patients versus 2.6 years in negative cases (p<0.005). Conclusions: Taken together our results support a role for ITGB7 in MM cells migration, homing and survival and pave the way for a novel therapeutic approach targeting this molecule. Disclosures: Bahlis: Celgene: Honoraria, Speakers Bureau; OrthoBiotech: Honoraria, Speakers Bureau.
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 | 0,001 |
| 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 ».