Dataset Information

Small Molecule that Reverses Dexamethasone Resistance in T-cell Acute Lymphoblastic Leukemia (T-ALL).

ABSTRACT: Glucocorticoids are one of the most utilized and effective therapies in treating T-cell acute lymphoblastic leukemia. However, patients often develop resistance to glucocorticoids, rendering these therapies ineffective. We screened 9517 compounds, selected for their lead-like properties, chosen from among 3?372?615 compounds, against a dexamethasone-resistant T-ALL cell line to identify small molecules that reverse glucocorticoid resistance. We synthesized analogues of the most effective compound, termed J9, from the screen in order to define the scaffold's structure-activity relationship. Active compounds restored sensitivity to glucocorticoids through upregulation of the glucocorticoid receptor. This compound and mechanism may provide a strategy for overcoming glucocorticoid resistance in patients with T-ALL.

SUBMITTER: Cantley AM

PROVIDER: S-EPMC4094258 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature

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Small Molecule that Reverses Dexamethasone Resistance in T-cell Acute Lymphoblastic Leukemia (T-ALL).

Cantley Alexandra M AM Welsch Matthew M Ambesi-Impiombato Alberto A Sanchez-Martin Marta M Kim Mi-Yeon MY Bauer Andras A Ferrando Adolfo A Stockwell Brent R BR

ACS medicinal chemistry letters 20140425 7

Glucocorticoids are one of the most utilized and effective therapies in treating T-cell acute lymphoblastic leukemia. However, patients often develop resistance to glucocorticoids, rendering these therapies ineffective. We screened 9517 compounds, selected for their lead-like properties, chosen from among 3 372 615 compounds, against a dexamethasone-resistant T-ALL cell line to identify small molecules that reverse glucocorticoid resistance. We synthesized analogues of the most effective compoun ...[more]

PMID: 25050160

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Project description:Response to dexamethasone (DEXA), as a hallmark drug in the treatment of childhood acute lymphoblastic leukemia (ALL), is one of the pivotal prognostic factors in the prediction of outcome in ALL. Identification of predictive markers of chemoresistance is beneficial to selecting of the best therapeutic protocol with the lowest effect adverse. Hence, we aimed to find drug targets using the 2DE/MS proteomics study of a DEXA-resistant cell line (REH) as a model for poor DEXA responding patients before and after drug treatment. Using the proteomic methods, three differentially expressed proteins were detected, including voltage dependent anion channel 1 (VDAC1), sorting Nexin 3 (SNX3), and prefoldin subunit 6 (PFDN6). We observed low expression of three proteins after DEXA treatment in REH cells. We subsequently verified low expression of resulted proteins at the mRNA level using the quantitative PCR method. These proteins are promising proteins because of their important roles in drug resistance and regulation of apoptosis (VDAC1), protein trafficking (SNX3), and protein folding (PFDN6). Additionally, mRNA expression level of these proteins was assessed in 17 bone marrow samples from children with newly diagnosed ALL and 7 non-cancerous samples as controls. The results indicated that independent of the molecular subtypes of leukemia, mRNA expression of VDAC1, SNX3, and PFDN6 decreased in ALL samples compared with non-cancerous samples particularly in VDAC1 (p < 0.001). Additionally, mRNA expression of three proteins was also declined in high-risk samples compared with standard risk cases. These results demonstrated diagnostic and prognostic value of these proteins in childhood ALL. Furthermore, investigation of protein-protein interaction using STRING database indicated that these proteins involved in the signaling pathway of NR3C1 as dexamethasone target. In conclusion, our proteomic study in DEXA resistant leukemic cells revealed VDAC1, SNX3, and PFDN6 are promising proteins that might serve as potential biomarkers of prognosis and chemotherapy in childhood ALL.

Project description:Drug resistance in acute lymphoblastic leukemia (ALL) remains a major problem warranting new treatment strategies. Wnt/catenin signaling is critical for the self-renewal of normal hematopoietic progenitor cells. Deregulated Wnt signaling is evident in chronic and acute myeloid leukemia; however, little is known about ALL. Differential interaction of catenin with either the Kat3 coactivator CREBBP (CREB-binding protein (CBP)) or the highly homologous EP300 (p300) is critical to determine divergent cellular responses and provides a rationale for the regulation of both proliferation and differentiation by the Wnt signaling pathway. Usage of the coactivator CBP by catenin leads to transcriptional activation of cassettes of genes that are involved in maintenance of progenitor cell self-renewal. However, the use of the coactivator p300 leads to activation of genes involved in the initiation of differentiation. ICG-001 is a novel small-molecule modulator of Wnt/catenin signaling, which specifically binds to the N-terminus of CBP and not p300, within amino acids 1-110, thereby disrupting the interaction between CBP and catenin. Here, we report that selective disruption of the CBP/?- and ?-catenin interactions using ICG-001 leads to differentiation of pre-B ALL cells and loss of self-renewal capacity. Survivin, an inhibitor-of-apoptosis protein, was also downregulated in primary ALL after treatment with ICG-001. Using chromatin immunoprecipitation assay, we demonstrate occupancy of the survivin promoter by CBP that is decreased by ICG-001 in primary ALL. CBP mutations have been recently identified in a significant percentage of ALL patients, however, almost all of the identified mutations reported occur C-terminal to the binding site for ICG-001. Importantly, ICG-001, regardless of CBP mutational status and chromosomal aberration, leads to eradication of drug-resistant primary leukemia in combination with conventional therapy in vitro and significantly prolongs the survival of NOD/SCID mice engrafted with primary ALL. Therefore, specifically inhibiting CBP/catenin transcription represents a novel approach to overcome relapse in ALL.

Dataset Information

Small Molecule that Reverses Dexamethasone Resistance in T-cell Acute Lymphoblastic Leukemia (T-ALL).

Publications

Small Molecule that Reverses Dexamethasone Resistance in T-cell Acute Lymphoblastic Leukemia (T-ALL).

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