A High-Throughput Screen Indicates Gemcitabine and JAK Inhibitors May be Useful for Treating Pediatric AML

Improvement in survival has been achieved for children and adolescents with AML but is largely attributed to enhanced supportive care as opposed to the development of better treatment regimens. High risk subtypes continue to have poor outcomes with event free survival rates \u3c 40% despite the use of high intensity chemotherapy in combination with hematopoietic stem cell transplant. Here we combine high-throughput screening, intracellular accumulation assays, and in vivo efficacy studies to identify therapeutic strategies for pediatric AML. We report therapeutics not currently used to treat AML, gemcitabine and cabazitaxel, have broad anti-leukemic activity across subtypes and are more effective relative to the AML standard of care, cytarabine, both in vitro and in vivo. JAK inhibitors are selective for acute megakaryoblastic leukemia and significantly prolong survival in multiple preclinical models. Our approach provides advances in the development of treatment strategies for pediatric AML

Prognostic and biologic significance of long non-coding RNA profiling in younger adults with cytogenetically normal acute myeloid leukemia

Long non-coding ribonucleic acids (RNAs) are a novel class of RNA molecules, which are increasingly recognized as important molecular players in solid and hematologic malignancies. Herein we investigated whether long non-coding RNA expression is associated with clinical and molecular features, as well as outcome of younger adults (aged <60 years) with de novo cytogenetically normal acute myeloid leukemia. Whole transcriptome profiling was performed in a training (n=263) and a validation set (n=114). Using the training set, we identified 24 long non-coding RNAs associated with event-free survival. Linear combination of the weighted expression values of these transcripts yielded a prognostic score. In the validation set, patients with high scores had shorter disease-free (P<0.001), overall (P=0.002) and event-free survival (P<0.001) than patients with low scores. In multivariable analyses, long non-coding RNA score status was an independent prognostic marker for disease-free (P=0.01) and event-free survival (P=0.002), and showed a trend for overall survival (P=0.06). Among multiple molecular alterations tested, which are prognostic in cytogenetically normal acute myeloid leukemia, only double CEBPA mutations, NPM1 mutations and FLT3-ITD associated with distinct long non-coding RNA signatures. Correlation of the long non-coding RNA scores with messenger RNA and microRNA expression identified enrichment of genes involved in lymphocyte/leukocyte activation, inflammation and apoptosis in patients with high scores. We conclude that long non-coding RNA profiling provides meaningful prognostic information in younger adults with cytogenetically normal acute myeloid leukemia. In addition, expression of prognostic long non-coding RNAs associates with oncogenic molecular pathways in this disease. clinicaltrials.gov Identifier: 00048958 (CALGB-8461), 00899223 (CALGB-9665), and 00900224 (CALGB-20202)

Interaction of imatinib with human organic ion carriers

Purpose: The activity of imatinib in leukemia has recently been linked with expression of the organic cation transporter 1 (OCT1) gene SLC22A1. Here, we characterized the contribution of solute carriers to imatinib transport in an effort to further understand mechanisms involved in the intracellular uptake and retention (IUR) of the drug. Experimental Design: IUR of [3H] imatinib was studied in Xenopus laevis oocytes and HEK293 cells expressing OATP1A2, OATP1B1, OATP1B3, OCT1-3, OCTN1-2, or OAT1-3. Gene expression was determined in nine leukemia cell lines using the Affymetrix U133 array. Results: Imatinib was not found to be a substrate for OCT1 in oocytes (P = 0.21), whereas in HEK293 cells IUR was increased by only 1.20-fold relative to control cells (P = 0.002). Further-more, in 74 cancer patients, the oral clearance of imatinib was not significantly altered in individuals carrying reduced-function variants in SLC22A1 (P = 0.99). Microarray analysis indicated that SLC22A1 was interrelated with gene expression of various transporters, including ABCB1, ABCC4, ABCG2 (negative), and OATP1A2 (positive). Imatinib was confirmed to be a substrate for the three efflux transporters (P < 0.05) as well as for OATP1A2 (P = 0.0001). Conclusions: This study suggests that SLC22A1 expression is a composite surrogate for expression of various transporters relevant to imatinib IUR. This observation provides a mechanistic explanation for previous studies that have linked SLC22A1 with the antitumor activity of imatinib. Because of its high expression in the intestine, ciliary body, gliomas, and leukemia cells, OATP1A2 may play a key role in imatinib pharmacokinetics-pharmacodynamics

Mutational landscape and gene-expression patterns in adult acute myeloid leukemias with monosomy 7 as a sole abnormality

Monosomy of chromosome 7 is the most frequent autosomal monosomy in acute myeloid leukemia (AML), where it associates with poor clinical outcomes. However, molecular features associated with this sole monosomy subtype (-7 AML) which may give insights into the basis for its poor prognosis have not been characterized. In this study, we analyzed 36 cases of -7 AML for mutations in 81 leukemia/cancer-associated genes using a customized targeted next-generation sequencing panel (Miseq). Global gene and microRNA expression profiles were also determined using paired RNA and small RNA sequencing data. Notably, gene mutations were detected in all the major AML-associated functional groups, which include activated signaling, chromatin remodeling, cohesin complex, methylation, NPM1, spliceosome, transcription factors and tumor suppressors. Gene mutations in the activated signaling and chromatin remodeling groups were relatively more frequent in patients <60 years of age, who also had more mutations in the methylation and spliceosome groups compared to patients greater than or equal to 60 years of age. Novel recurrent mutational events in AML were identified in the SMARCA2 gene. In patients greater than or equal to 60 years of age, the presence of spliceosome mutations associated with a lower complete remission rate (p=0.03). RNA sequencing revealed distinct gene and microRNA expression patterns between the sole -7 and non-7 AML cases, with reduced expression as expected of many genes and microRNAs mapped to chromosome 7, and overexpression of ID1, MECOM, and PTPRM, among others. Overall, our findings illuminate a number of molecular features of the underlying aggressive pathobiology in -7 AML patients

TP-0903 is active in models of drug-resistant acute myeloid leukemia

Effective treatment for AML is challenging due to the presence of clonal heterogeneity and the evolution of polyclonal drug resistance. Here, we report that TP-0903 has potent activity against protein kinases related to STAT, AKT, and ERK signaling, as well as cell cycle regulators in biochemical and cellular assays. In vitro and in vivo, TP-0903 was active in multiple models of drug-resistant FLT3 mutant AML, including those involving the F691L gatekeeper mutation and bone marrow microenvironment–mediated factors. Furthermore, TP-0903 demonstrated preclinical activity in AML models with FLT3-ITD and common co-occurring mutations in IDH2 and NRAS genes. We also showed that TP-0903 had ex vivo activity in primary AML cells with recurrent mutations including MLL-PTD, ASXL1, SRSF2, and WT1, which are associated with poor prognosis or promote clinical resistance to AML-directed therapies. Our preclinical studies demonstrate that TP-0903 is a multikinase inhibitor with potent activity against multiple drug-resistant models of AML that will have an immediate clinical impact in a heterogeneous disease like AML