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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

Project description:This phase I/II neoadjuvant trial determined maximally-tolerated doses (MTD), dose-limiting toxicities (DLT), response-to-therapy, and explored the role of new response biomarkers. The combination regimens were delivered with acceptable toxicity, good clinical response, inducing changes in tumor RNA content and integrity. Pre-treatment gene expressions impacted clinical response, including several near 17q12, which with ERBB2, may better identify chemoresponsiveness. The NCIC Clinical Trials Group MA.22 phase I/II clinical trial (ClinicalTrials.gov identifier NCT00066443) sought to determine the optimal dosing regimens for docetaxel/epirubicin combination chemotherapy in women with locally advanced (over 95% of patients) or inflammatory breast cancer. The protocol was approved by Health Canada and local Ethics Review Boards, and patients provided written, informed consent. Various doses of epirubicin and docetaxel were administered to patients in either a standard q3 weekly (Schedule A) or dose dense q2 weekly (Schedule B) regimen. Doses for Schedule A were 75 mg/m2 IV of docetaxel and 75, 90, 105, or 120 mg/m2 IV of epirubicin (with 6 mg of pegfilgrastim per cycle on day 2 to prevent neutropenia). Doses for both docetaxel and epirubicin in Schedule B were 50, 60, and 70 mg/m2 IV (with identical pegfilgrastim support). For each schedule, phase I was dose finding for phase II. Patients were allocated to the various phases and dosing regimens of the trial without randomization. None of the patients received trastuzumab in the initial years of the study and HER2+ patients were not enrolled on study, once trastuzumab funding became available. Six tumor biopsy cores were obtained pre-, mid-, and post-treatment: 3 cores for pathologic assessment; 3 cores for microarray studies. Total RNA was isolated from these cores and RNA integrity was assessed using Agilent Bioanalyzer. One of the RNA samples with the best quality was used for microarray study. One colour microarray of Agilent whole human genome nucleotide arrays was conducted with one array per patient. The current data set represents pre-treatment set. MA.22 clinical trial accrued T3N0, any N2 or N3, and T4 breast cancer patients (according to the classification described at; http://emedicine.medscape.com/article/2007112-overview). However, since the current study does not focus on the tumor grade/stage, the information was not provided in the current records.

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Gene expression arrays on lung cancer cells exposed to Notch inhibitor

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