Project description:CRABP2 potently suppresses carcinoma cell growth, yet the mechanism(s) that underlie this activity remain incompletely understood. Two distinct functions are known for CRABP2: 1) the classical function of this protein is to directly deliver retinoic acid (RA) to the nuclear retinoic-acid receptorthereby activate gene expression, and 2) in the absence of RA, CRABP2 directly binds to the RNA-binding and stabilizing protein, HuR, and markedly strengthens its interactions with target mRNAs. We used microarray experiments to elucidated genes regulated by HuR and/or CRABP2 in the absence of retinoic acid.
Project description:CRABP2 potently suppresses carcinoma cell growth, yet the mechanism(s) that underlie this activity remain incompletely understood. Two distinct functions are known for CRABP2: 1) the classical function of this protein is to directly deliver retinoic acid (RA) to the nuclear retinoic-acid receptorthereby activate gene expression, and 2) in the absence of RA, CRABP2 directly binds to the RNA-binding and stabilizing protein, HuR, and markedly strengthens its interactions with target mRNAs. We used microarray experiments to elucidated genes regulated by HuR and/or CRABP2 in the absence of retinoic acid. Two experiments were preformed: 1) Transcriptome profiles of MCF-7 cells overexpresssing shHuR were compared to control cells, both in the absence of retinoic acid. 2) Transcriptome profiles of MCF-7 cells overexpresssing shCRABP2 were compared to control cells, both in the absence of retinoic acid.
Project description:Cellular retinoic acid-binding protein 2, encoded by the CRABP2 gene, is a protein that facilitates retinoic acid binding to its cognate receptor complex and transport to the nucleus. Our analysis indicates that CRABP2 expression is upregulated in thyroid cancer and is involved in the invasiveness of thyroid cancer. Loss- and gain-of-function approaches were used to elucidate its oncogenic mechanisms.
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:Cellular retinoic acid-binding protein 1 (CRABP1) is a cytosolic lipid-binding protein which is thought to play an important role in regulating retinoic acid signaling. Loss of CRABP1 expression has been observed in thyroid cancer. We transfected a CRABP1-overexpressing vector to thyroid cancer cells to elucidate its oncogenic effects.
Project description:Arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) combination safely cures fatal acute promyelocytic leukemia, but the mechanisms underlying their action and synergy remain elusive. ATRA inhibits APL, breast and liver cancers by targeting isomerase Pin1, a master regulator of oncogenic signaling. Here we show that ATO targets Pin1 and cooperates with ATRA to exert potent anticancer activity. ATO inhibits and degrades Pin1, and suppresses its oncogenic function by noncovalent binding to Pin1’s active site. ATRA increases cellular ATO uptake through upregulating aquaporin-9. ATO and ATRA, at clinically safe doses, cooperatively ablate Pin1 to block numerous cancer-driving pathways and inhibit the growth of triple-negative breast cancer cells and tumor-initiating cells in cell and animal models including patient-derived orthotopic xenografts, similar to Pin1 CRISPR knockout, which is substantiated by comprehensive protein and microRNA analyses. Thus, synergistic Pin1 inhibition by ATO and ATRA offers an attractive approach to combating breast and other cancers.
Project description:Arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) combination safely cures fatal acute promyelocytic leukemia, but the mechanisms underlying their action and synergy remain elusive. ATRA inhibits APL, breast and liver cancers by targeting isomerase Pin1, a master regulator of oncogenic signaling. Here we show that ATO targets Pin1 and cooperates with ATRA to exert potent anticancer activity. ATO inhibits and degrades Pin1, and suppresses its oncogenic function by noncovalent binding to Pin1’s active site. ATRA increases cellular ATO uptake through upregulating aquaporin-9. ATO and ATRA, at clinically safe doses, cooperatively ablate Pin1 to block numerous cancer-driving pathways and inhibit the growth of triple-negative breast cancer cells and tumor-initiating cells in cell and animal models including patient-derived orthotopic xenografts, similar to Pin1 CRISPR knockout, which is substantiated by comprehensive protein and microRNA analyses. Thus, synergistic Pin1 inhibition by ATO and ATRA offers an attractive approach to combating breast and other cancers.
Project description:Retinoic acid Receptor Beta (RARβ) protein encoded by RARβ gene is a nuclear receptor protein that binds to retinoic acid (RA) to mediate RA function in cellular signalling in embryogenic morphogenesis, cell growth and differentiation. However, the function of RARβ in cancer stem cells (CSCs) maintenance of non-small cell lung cancer (NSCLC) is yet to be determined We used microarrays to analyse the trancriptomic changes in lung cancer and cancer stem cells following RARβ silencing.
Project description:Retinoic acid promotes the in vitro growth, patterning and improves the cellular composition of human pluripotent stem-cell-derived intestinal organoids
Project description:Retinoic acid (RA) triggers growth-suppressive effects in tumor cells and therefore RA and its synthetic analogs have great potential as anti-carcinogenic agents. RA effects are mediated by retinoic acid receptors (RARs), which regulate gene expression in an RA-dependent manner. To define the genetic network regulated by RARs in breast cancer cells, we identified RAR genomic targets using chromatin immunoprecipitation and expression analysis in a model breast cancer cell line MCF-7. Furthermore, we identified genomic binding sites for two putative RAR coregulators FoxA1 and GATA3. Keywords: ChIP-Chip Analysis