Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Transcription profiling of human gamma-secretase inhibitor-sensitive and -resistant T-ALL cell lines

ABSTRACT: Gain-of-function mutations in NOTCH1 are common in T-cell lymphoblastic leukemias making this receptor a promising target for drugs such as gamma-secretase inhibitors, which block a proteolytic cleavage required for NOTCH1 activation. However, the enthusiasm for these therapies has been tempered by tumor resistance and the paucity of information on the oncogenic programs regulated by oncogenic NOTCH1. Here we show that NOTCH1 regulates PTEN expression and the activity of the PI3K-AKT signaling pathway in normal and leukemic T cells. Notch signaling and the PI3K-AKT pathway synergize in vivo in a Drosophila model of Notch-induced tumorigenesis, and mutational loss of PTEN is associated with increased glycolysis and resistance to NOTCH1 inhibition in human T-ALL. These findings identify the transcriptional regulation of PTEN and the control of cellular metabolism as key elements of the oncogenic program activated by NOTCH1 and provide the basis for the design of new therapeutic strategies for T-ALL. Experiment Overall Design: Samples for microarray analysis were prepared and hybridized in Affymetrix Human U133 Plus 2.0 arrays according to the manufacturerâs instructions and as previously described. RNA was extracted from duplicate cultures of GSI-sensitive (ALL-SIL, CUTLL1, DND41, HPB-ALL, KOPTK1) and GSI-resistant (CCRF-CEM, MOLT3, P12 ICHIKAWA, PF382 and RPMI8402) T-ALL cell lines treated for 24 h with vehicle (DMSO) or 500 nM CompE. Interarray intensity differences were normalized with Dchip

ORGANISM(S): Homo sapiens

SUBMITTER: Adolfo Ferrando

PROVIDER: E-GEOD-5682 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Mutational loss of PTEN induces resistance to NOTCH1 inhibition in T-cell leukemia.

Palomero Teresa T Sulis Maria Luisa ML Cortina Maria M Real Pedro J PJ Barnes Kelly K Ciofani Maria M Caparros Esther E Buteau Jean J Brown Kristy K Perkins Sherrie L SL Bhagat Govind G Agarwal Archana M AM Basso Giuseppe G Castillo Mireia M Nagase Satoru S Cordon-Cardo Carlos C Parsons Ramon R Zúñiga-Pflücker Juan Carlos JC Dominguez Maria M Ferrando Adolfo A AA

Nature medicine 20070916 10

Gain-of-function mutations in NOTCH1 are common in T-cell lymphoblastic leukemias and lymphomas (T-ALL), making this receptor a promising target for drugs such as gamma-secretase inhibitors, which block a proteolytic cleavage required for NOTCH1 activation. However, the enthusiasm for these therapies has been tempered by tumor resistance and the paucity of information on the oncogenic programs regulated by oncogenic NOTCH1. Here we show that NOTCH1 regulates the expression of PTEN (encoding phos ...[more]

PMID: 17873882

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Project description:Somatic NOTCH1 mutations are found in ~60% of T lineage acute lymphoblastic leukemias (T-ALLs). Notch1 is cleaved by γ secretase to generate activated Notch intracellular domain (NICD) proteins. The NOTCH1 mutations found in T-ALL constitutively activate Notch1 signaling by increasing NICD levels. Genetic alterations in components of the Ras/PI3 kinase (PI3K)/Akt pathway are also highly prevalent in T-ALL, and often coexist with NOTCH1 mutations. Exposing a T-ALL cell line to the PI3 kinase (PI3K) inhibitor GDC-0941 generated drug resistant clones that down-regulated NICD expression. To address the in vivo relevance of this unexpected observation, we transplanted primary wild-type (WT) and KrasG12D mutant T-ALLs into recipient mice, and treated them with GDC-0941 alone and in combination with the MEK inhibitor PD0325901 (PD901). Although many leukemias responded dramatically to these targeted agents in vivo, drug-resistant clones invariably emerged. Multiple resistant T-ALLs lost NICD expression through mechanisms that included loss of Notch1 mutations found in the parental T-ALL. These GDC-0941-resistant leukemias exhibited reduced expression of many Notch1 target genes, elevated levels of phosphorylated Akt (pAkt), and displayed cross-resistance to γ secretase inhibitors (GSIs). Consistent with these data, inhibiting Notch1 activity in T-ALL cells enhanced PI3K signaling, providing a likely mechanism for in vivo selection against clones with Notch1 pathway activation. Thus, oncogenic Notch1 mutations that promote clonal outgrowth during malignant transformation unexpectedly “switch” to become deleterious during treatment with a PI3K inhibitor. These data advance our understanding of T-ALL pathogenesis and have implications for implementing new therapeutic regimens. We analyzed 28 mouse T-ALL samples obtained after in vivo treatment with GDC-0941 alone or GDC-0941 + PD0325901. These T-ALL samples are either Kras wild type or harbor a KrasG12D mutations.

Dataset Information

Transcription profiling of human gamma-secretase inhibitor-sensitive and -resistant T-ALL cell lines

Publications

Mutational loss of PTEN induces resistance to NOTCH1 inhibition in T-cell leukemia.

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