RNA Splicing Modulation Impairs Acute Myeloid Leukemia Stem Cell Maintenance

Autor: Edward D. Ball, Reymundo Villa, Anil Sadarangani, Maria A. Zipeto, Leslie Crews, Anna A. Kulidjian, Michael D. Burkart, Angela C. Court, Nathaniel Delos Santos, Heather Leu, James J. La Clair, Sheldon R. Morris, Larissa Balaian, Catriona Jamieson, Rainer Storb
Rok vydání: 2015
Předmět:
Zdroj: Blood. 126:567-567
ISSN: 1528-0020
0006-4971
DOI: 10.1182/blood.v126.23.567.567
Popis: Introduction Disease relapse is the leading cause of death in secondary AML (sAML), which evolves from antecedent hematologic disorders like myelodysplastic syndrome (MDS) or myeloproliferative neoplasms (MPNs) or following exposure to chemotherapy. Persistence of therapy-resistant leukemia stem cells (LSC) harboring enhanced survival and self-renewal capacity has been linked to high relapse rates in sAML. Previously, we showed that missplicing of a stem cell regulatory gene, GSK3 b, and splice isoform switching favoring pro-survival BCL2 family isoform expression promoted generation of therapy-resistant LSC (Abrahamsson et al PNAS 2009; Goff et al Cell Stem Cell 2013). However, whether aberrant pre-mRNA splicing promotes sAML LSC generation, in the absence of mutation, and if pharmacological splicing modulation impairs LSC maintenance, in a mutation-independent manner, has not been elucidated. Methods and Results Comparative RNA-sequencing and gene set enrichment analyses revealed significant alterations in splicing factor gene expression in purified progenitors from untreated sAML compared with normal samples. In addition, using an isoform-specific alignment algorithm, we established a sAML LSC splice isoform expression signature that identified increased expression of select transcripts, e.g. CD82 and PTK2B. Thus, we investigated the LSC inhibitory efficacy of a stable, potent splicing modulatory agent, 17S -FD-895, in humanized AML LSC stromal co-culture and primagraft assays. Notably, there was a dose-dependent reduction in AML LSC (n=4) survival and self-renewal after in vitro 17S -FD-895 treatment, with a favorable therapeutic index compared to normal controls (n=3, p Flow cytometric analyses in AML LSC primagraft models treated with 17S -FD-895 (5-10 mg/kg delivered intravenously in 3 doses over 2 weeks) revealed a decrease in human stem (CD45+ CD34+ CD38- Lin-, 68% reduction in the spleens of the 10 mg/kg group versus vehicle controls, n=5 mice per group, p Conclusions Here we demonstrate that a potent and stable splicing modulatory agent, 17S -FD-895, normalized sAML-specific splice isoform expression patterns as well as MCL1-L/S and BLC2-L/S ratios. Moreover, pharmacologic splicing modulation reduced AML LSC survival and self-renewal in a dose-dependent manner in both in vitro and in vivo models with a favorable therapeutic index. Further evaluation of this compound as a splicing-targeted single agent or combined with standard of care therapy may reduce or eradicate LSC burden in therapy-resistant sAML. In addition, LSC-specific splice isoforms may represent important biomarkers that could be developed as companion diagnostics for splicing-targeted therapies in sAML and other recalcitrant malignancies. Disclosures Jamieson: Johnson & Johnson: Research Funding; GlaxoSmithKline: Research Funding.
Databáze: OpenAIRE
Externí odkaz: