Irradiated NK-92 Targets AML Leukemic Stem Cells in Vivo and Gene-Modified CD16+NK-92 Mediates Antibody Dependent Cell Mediated Cytotoxicity (ADCC) Against CD123+ Cells
Notice bibliographique
Résumé
Abstract Abstract 1909 Introduction: Patients with acute myeloid leukemia (AML) in remission relapse frequently from residual leukemic stem cells (LSCs) that are CD34+CD38-CD123+. NK-92 is an infusible CD16- malignant NK cell line cytotoxic against AML and after irradiation for prevention of NK cell malignancy has minimal adverse events in Phase I trials. Here, we tested irradiated NK-92 (iNK-92) against primary AML in a NOD/SCID gamma null (NSG) xenograft model. To optimize killing of LSCs in vitro we utilized a gene modified CD16+NK-92 against the CD123+ leukemia cell line OCI/AML5 treated with and without an anti-CD123 monoclonal antibody (7G3) to facilitate antibody dependent cell mediated cytotoxicity (ADCC). Methods: NSG mice were irradiated with 225 or 325 cGy before infusion with primary AML blasts (1 or 3×10e6 cells). iNK-92 was started 1 or 10 days post AML infusion and given 1–3 times weekly (15 or 20×10e6 cells/dose) to a total dose of 60–75 ×10e6 cells/mouse. In vitro cytotoxicity was measured by the chromium release assay. OCI/AML5 or primary AML was pretreated with 7G3 or anti-Class I antibody respectively at 10 ug/ml 2 hours before ADCC assays. Results: We developed an NSG AML xenograft model using a CD34+CD38+ primary AML sample containing a small fraction of CD34+CD38- cells that were predominantly CD123+. 3×10e6 primary cells induced leukemia in NSG mice by 6 weeks and maintained comparable potency up to quaternary transplantations with a stable immunophenotype. In vitro cytotoxicity against LSCs was assessed by treating 1×10e6 first passage BM derived primary AML +/− 5×10e6 iNK-92 ×4 hours and injecting into 2 cohorts of 5 mice. At 6 weeks mice were sacrificed and bone marrow harvested. Average leukemic engraftment in the iNK-92 group (79.8, 3.48, 92.1, 81.3, 86.1, Av= 68.6%) was less than untreated AML inoculated group (95.0, 93.4, 19.4, 95, 97.3, Av=80.0%), but not statistically significant (p=0.62). Removing one poorly engrafted outlier mouse from each group yielded a higher engraftment in the control (Av=95.1%) versus the treatment group (Av=84.8%) and was significant (p=0.011). To test iNK-92 to treat engrafted leukemia, NSG mice were infused with 3×10e6 AML cells starting day 10 with 20×10e6 iNK-92 weekly ×6 doses. Survival was improved in the treatment group to near statistical significance (p=0.055), but all mice ultimately succumbed to disease. Addition of IL-2 to iNK-92 did not improve outcomes (p=0.13). 3×10e6 primary AML cells were also infused into 2 cohorts of 4 mice and treated +/− iNK-92 from day 2 and given 15×10e6 cells twice weekly to 75×10e6 total dose. BM (1×10e6 cells) from each of 4 primary recipients in control and treatment was serially transplanted 1:1 into four new NSG mice. BM engraftment occurred in all AML only cohort secondary mice (80.8, 93.3, 80.4, 96.4 Av=87.7%) while one mouse from iNK-92 group was leukemia free with engraftment at background levels of non-injected mice (96.4, 94.7, 1.8, 95.7 Av=72.2%). Proportion of LSCs in secondary transplanted mice was: AML (8.01, 9.48, 8.66, 5.25, Av=7.85%) and AML + iNK-92 (7.13, 3.46, 0.03, 4.0 Av=3.66%) which was statistically significant (p=0.05). CD16+NK-92 killed CD123+ OCI/AML5 cells at effector:target (E:T) ratios of 25:1, 10:1, 5:1 and 1:1 (% lysis +/−SD: 35.0 +/−4.0, 9.0+/−6.6, -2.0 +/−0.1, 1.7 +/−3.3) and was significantly enhanced (2–6x) when targets were coated with anti-CD123 mAb (% lysis +/−SD: 64.3 +/−3.1, 48.5 +/−4.1, 20.9 +/−0.1, 10.1+/−3.3). Further, CD16+NK-92 also killed primary AML at E:T ratios of 25:1, 10:1, 5:1 and 1:1 (% lysis +/−SD: 34.7 +/−4.6, 15.6 +/− 4.7, 11.5 +/− 2.0, 7.7 +/−1.6) which was significantly enhanced (2–3x) by coating with anti-Class I monoclonal antibodies (% lysis +/−SD: 64.8 +/−10.4, 31.1 +/− 8.9, 30.2 +/− 9.4, 23.9+/−2.8). Conclusion: iNK-92 reduces engraftment of AML and improves survival in a primary AML xenograft model. CD16+NK-92 cytotoxicity against primary AML is enhanced with anti-class I antibodies via ADCC, demonstrating that CD16+NK-92 can be redirected against bulk primary leukemia using a highly expressed cell surface marker. Finally, CD16+NK-92 cytotoxicity can be improved against OCI/AML5 with anti-CD123 antibodies via ADCC, providing the first proof-of-principle for the targeting of leukemic stem cells by combining humoral and cellular approaches. Disclosures: No relevant conflicts of interest to declare.
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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 ».