| Autor: |
Roeten MSF; Cancer Center Amsterdam, Department of Hematology, Amsterdam UMC, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands., van Meerloo J; Cancer Center Amsterdam, Department of Hematology, Amsterdam UMC, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands., Kwidama ZJ; Cancer Center Amsterdam, Department of Hematology, Amsterdam UMC, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands., Ter Huizen G; Cancer Center Amsterdam, Department of Hematology, Amsterdam UMC, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands., Segerink WH; Cancer Center Amsterdam, Department of Hematology, Amsterdam UMC, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands., Zweegman S; Cancer Center Amsterdam, Department of Hematology, Amsterdam UMC, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands., Kaspers GJL; Princess Maxima Center of Pediatric Oncology, 3584 CS Utrecht, The Netherlands.; Emma Children's Hospital, Amsterdam UMC, Vrije Universiteit Amsterdam, Pediatric Oncology, 1105 AZ Amsterdam, The Netherlands., Jansen G; Amsterdam Rheumatology and Immunology Center, Cancer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands., Cloos J; Cancer Center Amsterdam, Department of Hematology, Amsterdam UMC, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands. |
| Abstrakt: |
At present, 20-30% of children with acute leukemia still relapse from current chemotherapy protocols, underscoring the unmet need for new treatment options, such as proteasome inhibition. Ixazomib (IXA) is an orally available proteasome inhibitor, with an improved safety profile compared to Bortezomib (BTZ). The mechanism of action (proteasome subunit inhibition, apoptosis induction) and growth inhibitory potential of IXA vs. BTZ were tested in vitro in human (BTZ-resistant) leukemia cell lines. Ex vivo activity of IXA vs. BTZ was analyzed in 15 acute lymphoblastic leukemia (ALL) and 9 acute myeloid leukemia (AML) primary pediatric patient samples. BTZ demonstrated more potent inhibitory effects on constitutive β5 and immunoproteasome β5i proteasome subunit activity; however, IXA more potently inhibited β1i subunit than BTZ (70% vs. 29% at 2.5 nM). In ALL/AML cell lines, IXA conveyed 50% growth inhibition at low nanomolar concentrations, but was ~10-fold less potent than BTZ. BTZ-resistant cells (150-160 fold) displayed similar (100-fold) cross-resistance to IXA. Finally, IXA and BTZ exhibited anti-leukemic effects for primary ex vivo ALL and AML cells; mean LC 50 (nM) for IXA: 24 ± 11 and 30 ± 8, respectively, and mean LC 50 for BTZ: 4.5 ± 1 and 11 ± 4, respectively. IXA has overlapping mechanisms of action with BTZ and showed anti-leukemic activity in primary leukemic cells, encouraging further pre-clinical in vivo evaluation. |
