Project description:Analysis of dexamethasone-stimulated A549 lung adenocarcinoma epithelial cells treated with a glucocorticoid response (GR) element (GRE) specific DNA binding polyamide. Polyamide designed to target the sequence 5'-WGWWCW-3' and disrupt GR-mediated gene expression. Effects of the GR antagonist mifepristone also examined.
Project description:Analysis of dexamethasone-stimulated A549 lung adenocarcinoma epithelial cells treated with a glucocorticoid response (GR) element (GRE) specific DNA binding polyamide. Polyamide designed to target the sequence 5'-WGWWCW-3' and disrupt GR-mediated gene expression. Effects of the GR antagonist mifepristone also examined. Experiment Overall Design: A549 cells were treated with compounds for 48 hours before RNA extraction and hybridization on Affymetrix microarrays.
Project description:Androgen Receptor (AR) is essential for the growth and progression of prostate cancer in both hormone-sensitive and hormone-refractory disease. We have designed a sequence-specific DNA binding polyamide (1) that targets the consensus androgen response element (ARE). This polyamide binds the PSA promoter ARE, inhibits androgen-induced expression of PSA and several other AR-regulated genes in cultured prostate cancer cells, and reduces AR occupancy at the PSA promoter and enhancer. Down-regulation of PSA by this polyamide was comparable to that produced by the synthetic anti-androgen bicalutamide (Casodex) at the same concentration. Genome-wide expression analysis reveals that a similar number of transcripts are affected by treatment with the polyamide and with bicalutamide. Direct inhibition of AR-DNA binding by sequence-specific DNA binding small molecules could offer an alternative approach to antagonizing AR activity. A polyamide (2) that targets a different DNA sequence is included as a control. Experiment Overall Design: DHT (dihydrotestosterone)-stimulated LNCaP cells that were treatment with polyamide 1, polyamide 2, bicalutamide were compared to control cells that were also DHT-stimulated. Cells not stimulated with DHT were also compared to the DHT-stimulated controls. Three biological replicates were included for each treatment/condition except the no-DHT induced controls, which were in biological duplicate.
Project description:Transcription mediated by hypoxia inducible factor (HIF-1) contributes to tumor angiogenesis and metastasis but is also involved in the activation of cell-death pathways and normal physiological processes. Given the complexity of HIF-1 signaling it could be advantageous to target a subset of HIF-1 effectors rather than the entire pathway. We compared the genome-wide effects of three molecules that each interfere with the HIF-1-DNA interaction: a polyamide targeted to the hypoxia response element (HRE), siRNA targeted to HIF-1α, and echinomycin, a DNA binding natural product with a similar but less specific sequence preference to the polyamide. The polyamide affects a subset of hypoxia-induced genes that are consistent with the binding site preferences of the polyamide. For comparison, siRNA targeted to HIF-1α and echinomycin each affect the expression of nearly every gene induced by hypoxia. Remarkably, the total number of genes affected by either polyamide or HIF-1α siRNA over a range of thresholds is comparable. The data shows how polyamides can be used to affect a subset of a pathway regulated by a transcription factor. In addition, this study offers a unique comparison of three complementary approaches towards exogenous control of endogenous gene expression. Experiment Overall Design: Hypoxia-mimetic DFO (deferoxamine)-stimulated U251 cells that were treated with polyamide 1, HIF-1α siRNA, and echinomycin were compared to control cells that were also DFO-stimulated. Cells not stimulated with DFO were also compared to the DFO-stimulated controls. Three biological replicates were included for each treatment/condition.
Project description:The model is based on publication:
Mathematical analysis of gefitinib resistance of lung adenocarcinoma caused by MET amplification
Abstract:
Gefitinib, one of the tyrosine kinase inhibitors of epidermal growth factor receptor (EGFR), is effective for treating lung adenocarcinoma harboring EGFR mutation; but later, most cases acquire a resistance to gefitinib. One of the mechanisms conferring gefitinib resistance to lung adenocarcinoma is the amplification of the MET gene, which is observed in 5–22% of gefitinib-resistant tumors. A previous study suggested that MET amplification could cause gefitinib resistance by driving ErbB3-dependent activation of the PI3K pathway. In this study, we built a mathematical model of gefitinib resistance caused by MET amplification using lung adenocarcinoma HCC827-GR (gefitinib resistant) cells. The molecular reactions involved in gefitinib resistance consisted of dimerization and phosphorylation of three molecules, EGFR, ErbB3, and MET were described by a series of ordinary differential equations. To perform a computer simulation, we quantified each molecule on the cell surface using flow cytometry and estimated unknown parameters by dimensional analysis. Our simulation showed that the number of active ErbB3 molecules is around a hundred-fold smaller than that of active MET molecules. Limited contribution of ErbB3 in gefitinib resistance by MET amplification is also demonstrated using HCC827-GR cells in culture experiments. Our mathematical model provides a quantitative understanding of the molecular reactions underlying drug resistance.
Project description:In order to identify and characterize novel human gene expression responses to glucocorticoids, we exposed the human lung adenocarcinoma cell line, A549, to the synthetic glucocorticoid dexamethasone for 1, 3, 5, 7, 9, and 11 hrs in duration as well as to a paired vehicle control, ethanol. We assayed gene expression with RNA-seq and clustered gene expression profiles using an infinite Gaussian process mixture model.
Project description:Androgen Receptor (AR) is essential for the growth and progression of prostate cancer in both hormone-sensitive and hormone-refractory disease. We have designed a sequence-specific DNA binding polyamide (1) that targets the consensus androgen response element (ARE). This polyamide binds the PSA promoter ARE, inhibits androgen-induced expression of PSA and several other AR-regulated genes in cultured prostate cancer cells, and reduces AR occupancy at the PSA promoter and enhancer. Down-regulation of PSA by this polyamide was comparable to that produced by the synthetic anti-androgen bicalutamide (Casodex) at the same concentration. Genome-wide expression analysis reveals that a similar number of transcripts are affected by treatment with the polyamide and with bicalutamide. Direct inhibition of AR-DNA binding by sequence-specific DNA binding small molecules could offer an alternative approach to antagonizing AR activity. A polyamide (2) that targets a different DNA sequence is included as a control. Keywords: Gene expression changes in cultured LNCaP cells after DHT-stimulation and various treatment conditions