Project description:Cistrome profiles of Retinoids x Receptor alpha (RXRα) , Retinoic Acid Receptor alpha (RARα), and Retinoic Acid Receptor beta (RARβ) in livers of mice treated by control and retionic acid-containing diet
Project description:Our project focuses on retinoic acid (RA) effect on hepatic lipid homeostasis. Even though RA has more than one receptor including retinoids x receptor (RXR) and retinoic acid receptor (RAR), most probably, RA effect on lipid homeostasis is mediated by RXR and its partners such as PXR, FXR, and PPAR. So we treated the wild type and RXRα-knockout mice by retinoic acid to check the global gene expression especially for lipid homeostasis genes. We used microarrays to observe the global gene expression underlying hepatic lipid homeostasis. We treated both the wild type and RXRα-KO mice with normal diet and RA-containing diet for 7 days. For each group, three replicates were done. Liver total RNA were used to test global gene expression by microarray.
Project description:Our project focuses on retinoic acid (RA) effect on hepatic lipid homeostasis. Even though RA has more than one receptor including retinoids x receptor (RXR) and retinoic acid receptor (RAR), most probably, RA effect on lipid homeostasis is mediated by RXR and its partners such as PXR, FXR, and PPAR. So we treated the wild type and RXRα-knockout mice by retinoic acid to check the global gene expression especially for lipid homeostasis genes. We used microarrays to observe the global gene expression underlying hepatic lipid homeostasis.
Project description:The aim of the experiment was to gain insight into the role of estrogen receptor beta (ERβ) isoforms in the response of breast cancer MCF7 cells to antiestrogens and retinoids. To this end, clones of MCF7 cells constitutively expressing human ERβ1 (MCF7-ERβ1) or ERβ2 (MCF7-ERβ2) were established and used for the determination of the global transcriptional changes induced upon treatment with hydroxytamoxifen (OHT) and all-trans retinoic acid (ATRA). Gene signatures associated with each clone will shed light to the mechanism underlying the ERβ1- and ERβ2-mediated response of MCF7 cells to antiestrogens and retinoids.
Project description:The overall study explores differential sensitivity of estrogen-receptor-positive and -negative breast carcinoma cells to retinoids via gene expression and microRNA profiling in MCF7 and MDA-MB-231 cells. This Series reports results of transcriptional profiling of breast carcinoma cell lines comparing the effects of retinoic acid treatment (6 and 48 hours) on estrogen-receptor-positive (MCF7) and estrogen-receptor-negative (MDA-MB-231) cells. mRNA profiling: Retinoic-acid-treated (1microM) vs vehicle-treated cells, two time points (6 and 48h), two cell lines (MCF7 and MDA-MB-231). Two biological replicates for each condition, balanced dye design.
Project description:Haffez2017 - RAR interaction with synthetic
analogues
This model is described in the article:
The molecular basis of the
interactions between synthetic retinoic acid analogues and the
retinoic acid receptors
Hesham Haffez, David R. Chisholm,
Roy Valentine, Ehmke Pohl, Christopher Redfern and Andrew
Whiting
MedChemComm
Abstract:
All-trans-retinoic acid (ATRA) and its synthetic analogues
EC23 and EC19 direct cellular differentiation by interacting as
ligands for the retinoic acid receptor (RARα,
β and γ) family of nuclear receptor
proteins. To date, a number of crystal structures of natural
and synthetic ligands complexed to their target proteins have
been solved, providing molecular level snap-shots of ligand
binding. However, a deeper understanding of receptor and ligand
flexibility and conformational freedom is required to develop
stable and effective ATRA analogues for clinical use.
Therefore, we have used molecular modelling techniques to
define RAR interactions with ATRA and two synthetic analogues,
EC19 and EC23, and compared their predicted biochemical
activities to experimental measurements of relative ligand
affinity and recruitment of coactivator proteins. A
comprehensive molecular docking approach that explored the
conformational space of the ligands indicated that ATRA is able
to bind the three RAR proteins in a number of conformations
with one extended structure being favoured. In contrast the
biologically-distinct isomer, 9-cis-retinoic acid (9CRA),
showed significantly less conformational flexibility in the RAR
binding pockets. These findings were used to inform docking
studies of the synthetic retinoids EC23 and EC19, and their
respective methyl esters. EC23 was found to be an excellent
mimic for ATRA, and occupied similar binding modes to ATRA in
all three target RAR proteins. In comparison, EC19 exhibited an
alternative binding mode which reduces the strength of key
polar interactions in RARα/γ but is
well-suited to the larger RARβ binding pocket. In
contrast, docking of the corresponding esters revealed the loss
of key polar interactions which may explain the much reduced
biological activity. Our computational results were
complemented using an in vitro binding assay based on FRET
measurements, which showed that EC23 was a strongly binding,
pan-agonist of the RARs, while EC19 exhibited specificity for
RARβ, as predicted by the docking studies. These
findings can account for the distinct behaviour of EC23 and
EC19 in cellular differentiation assays, and additionally, the
methods described herein can be further applied to the
understanding of the molecular basis for the selectivity of
different retinoids to RARα, β and
γ.
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Project description:The overall study explores differential sensitivity of estrogen-receptor-positive and -negative breast carcinoma cells to retinoids via gene expression and microRNA profiling in MCF7 and MDA-MB-231 cells. This Series reports results of transcriptional profiling of breast carcinoma cell lines comparing the effects of retinoic acid treatment (6 and 48 hours) on estrogen-receptor-positive (MCF7) and estrogen-receptor-negative (MDA-MB-231) cells.