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Gene expression arrays on lung cancer cells exposed to Notch inhibitor

ABSTRACT: Genes responses in A549 and H460 cells after GSI (RO4929097-001-003 , 2 uM) treatment. Notch signaling is an area of great interest in oncology. RO4929097 is a potent and selective inhibitor of gamma-secretase, producing inhibitory activity of Notch signaling in tumor cells. The RO4929097 IC50 in cell-free and cellular assays is in the low nanomolar range with >100-fold selectivity with respect to 75 other proteins of various types (receptors, ion channels, and enzymes). RO4929097 inhibits Notch processing in tumor cells as measured by the reduction of intracellular Notch expression by Western blot. This leads to reduced expression of the Notch transcriptional target gene Hes1. RO4929097 does not block tumor cell proliferation or induce apoptosis but instead produces a less transformed, flattened, slower-growing phenotype. RO4929097 is active following oral dosing. Antitumor activity was shown in 7 of 8 xenografts tested on an intermittent or daily schedule in the absence of body weight loss or Notch-related toxicities. Importantly, efficacy is maintained after dosing is terminated. Angiogenesis reverse transcription-PCR array data show reduced expression of several key angiogenic genes. In addition, comparative microarray analysis suggests tumor cell differentiation as an additional mode of action. These preclinical results support evaluation of RO4929097 in clinical studies using an intermittent dosing schedule. A multicenter phase I dose escalation study in oncology is under way.

ORGANISM(S): Homo sapiens

PROVIDER: GSE36176 | GEO | 2012/03/01

SECONDARY ACCESSION(S): PRJNA152915

REPOSITORIES: GEO

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Project description:Pancreatic ductal adenocarcinoma (PDAC) is a nearly uniformly lethal malignancy, with most patients facing an adverse clinical outcome. Given the pivotal role of aberrant Notch signaling in the initiation and progression of PDAC, we investigated the effect of MRK-003, a potent and selective γ-secretase inhibitor, in preclinical PDAC models. We used a panel of human PDAC cell lines, as well as patient-derived PDAC xenografts, to determine whether pharmacological targeting of the Notch pathway could inhibit pancreatic tumor growth and potentiate gemcitabine sensitivity. In vitro, MRK-003 treatment downregulated the canonical Notch target gene Hes-1, significantly inhibited anchorage independent growth, and reduced the subset of CD44+CD24+ and aldehyde dehydrogenase (ALDH)+ cells that have been attributed with tumor initiating capacity. Ex vivo pretreatment of PDAC cells with MRK-003 in culture significantly inhibited the subsequent engraftment in immunocompromised mice. In vivo, MRK-003 monotherapy significantly blocked tumor growth in 5 of 9 (56%) patient-derived PDAC xenografts. Moreover, a combination of MRK-003 and gemcitabine showed enhanced antitumor effects compared to gemcitabine alone in 4 of 9 (44%) PDAC xenografts. Baseline gene expression analysis of the treated xenografts indicated that upregulation of nuclear factor kappa B (NFκB) pathway components was associated with the sensitivity to single MRK-003, while upregulation in B-cell receptor (BCR) signaling and nuclear factor erythroid-derived 2-like 2 (NRF2) pathway correlated with response to the combination of MRK-003 with gemcitabine. The preclinical findings presented here provide further rationale for small molecule inhibition of Notch signaling as a therapeutic strategy in PDAC. Pancreatic ductal adenocarcinoma xenografts were grown in Athymic Nude-Foxn1nu mice. RNA was extracted and profiled in Affymetrix platform to identify genes correlating with sensitivity to MRK-003

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Gene expression arrays on lung cancer cells exposed to Notch inhibitor

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