The RNA-binding protein HuR stabilizes survivin mRNA in human oesophageal epithelial cells

2011 ◽  
Vol 437 (1) ◽  
pp. 89-96 ◽  
Author(s):  
James M. Donahue ◽  
Elizabeth T. Chang ◽  
Lan Xiao ◽  
Peng-Yuan Wang ◽  
Jaladanki N. Rao ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Oesophageal Cancer ◽  
Mrna Stability ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Survivin Expression ◽  
Transcriptional Level ◽  
Survivin Mrna ◽  
Hu Antigen R

Overexpression of survivin, a member of the IAP (inhibitor of apoptosis) family, has been correlated with poorer outcomes in multiple malignancies, including oesophageal cancer. The regulatory mechanisms, particularly at the post-transcriptional level, involved in survivin overexpression are not well understood. Previous work from our group has shown that the RNA-binding protein HuR (Hu antigen R), which is also overexpressed in several malignancies, stabilizes the mRNA of XIAP (X-linked IAP), another IAP family member. In the present study, we demonstrate the binding of HuR to a 288 bp fragment in the 3′-UTR (untranslated region) of survivin mRNA in human oesophageal epithelial cells. Unexpectedly, overexpression of HuR led to a decrease in survivin expression. This was associated with decreased survivin mRNA and promoter activity, suggesting a decrease in transcription. Levels of p53, a negative transcriptional regulator of survivin, increased following HuR overexpression, in conjunction with enhanced p53 mRNA stability. Silencing p53 prior to HuR overexpression resulted in increased survivin protein and mRNA stability. These results demonstrate that, in the absence of p53, HuR overexpression results in increased survivin mRNA stability and protein expression. This provides an additional explanation for the increased survivin expression observed in oesophageal cancer cells that have lost p53.

scholarly journals The RNA-binding protein CUG-BP1 increases survivin expression in oesophageal cancer cells through enhanced mRNA stability

2012 ◽  
Vol 446 (1) ◽  
pp. 113-123 ◽  
Author(s):  
Elizabeth T. Chang ◽  
James M. Donahue ◽  
Lan Xiao ◽  
Yuhong Cui ◽  
Jaladanki N. Rao ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Cancer Cells ◽  
Oesophageal Cancer ◽  
Mrna Stability ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Survivin Expression ◽  
Survivin Mrna ◽  
Induced Apoptosis

Survivin, a member of the IAP (inhibitor of apoptosis protein) family, plays important roles in maintaining cellular homoeostasis and regulating cell-cycle progression. This IAP is overexpressed in oesophageal cancer cells, leading to uncontrolled cell growth and resistance to apoptosis. CUG-BP1 (CUG-binding protein 1) is an RNA-binding protein that regulates the stability and translational efficiency of target mRNAs. In the present paper, we report that CUG-BP1 is overexpressed in oesophageal cancer cell lines and human oesophageal cancer specimens. CUG-BP1 associates with the 3′-untranslated region of survivin mRNA, thereby stabilizing the transcript and elevating its expression in oesophageal cancer cells. Our results show that overexpression of CUG-BP1 in oesophageal epithelial cells results in increased survivin mRNA stability and consequently survivin protein expression. Conversely, silencing CUG-BP1 in oesophageal cancer cells destabilizes survivin mRNA, lowering the level of survivin protein. In addition, we have found that altering CUG-BP1 expression modulates susceptibility to chemotherapy-induced apoptosis. Overexpression of CUG-BP1 in oesophageal epithelial cells increases resistance to apoptosis, whereas silencing CUG-BP1 makes oesophageal cancer cells more susceptible to chemotherapy-induced apoptosis. Co-transfection experiments with small interfering RNA directed against survivin suggest that the anti-apoptotic role for CUG-BP1 is not entirely dependent on its effect on survivin expression.

scholarly journals Post-transcriptional regulation of MEK-1 by polyamines through the RNA-binding protein HuR modulating intestinal epithelial apoptosis

2010 ◽  
Vol 426 (3) ◽  
pp. 293-306 ◽  
Author(s):  
Peng-Yuan Wang ◽  
Jaladanki N. Rao ◽  
Tongtong Zou ◽  
Lan Liu ◽  
Lan Xiao ◽  
...  
Keyword(s):  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Mitogen Activated Protein Kinase ◽  
Transcriptional Level ◽  
Intestinal Epithelial ◽  
Cellular Functions ◽  
Mitogen Activated Protein ◽  
Hu Antigen R ◽  
Post Transcriptional Regulation

MEK-1 [MAPK (mitogen-activated protein kinase) kinase-1] is an important signal transducing enzyme that is implicated in many aspects of cellular functions. In the present paper, we report that cellular polyamines regulate MEK-1 expression at the post-transcriptional level through the RNA-binding protein HuR (Hu-antigen R) in IECs (intestinal epithelial cells). Decreasing the levels of cellular polyamines by inhibiting ODC (ornithine decarboxylase) stabilized MEK-1 mRNA and promoted its translation through enhancement of the interaction between HuR and the 3′-untranslated region of MEK-1 mRNA, whereas increasing polyamine levels by ectopic ODC overexpression destabilized the MEK-1 transcript and repressed its translation by reducing the abundance of HuR–MEK-1 mRNA complex; neither intervention changed MEK-1 gene transcription via its promoter. HuR silencing rendered the MEK-1 mRNA unstable and inhibited its translation, thus preventing increases in MEK-1 mRNA and protein in polyamine-deficient cells. Conversely, HuR overexpression increased MEK-1 mRNA stability and promoted its translation. Inhibition of MEK-1 expression by MEK-1 silencing or HuR silencing prevented the increased resistance of polyamine-deficient cells to apoptosis. Moreover, HuR overexpression did not protect against apoptosis if MEK-1 expression was silenced. These results indicate that polyamines destabilize the MEK-1 mRNA and repress its translation by inhibiting the association between HuR and the MEK-1 transcript. Our findings indicate that MEK-1 is a key effector of the HuR-elicited anti-apoptotic programme in IECs.

scholarly journals Post-transcriptional regulation of Wnt co-receptor LRP6 and RNA-binding protein HuR by miR-29b in intestinal epithelial cells

2016 ◽  
Vol 473 (11) ◽  
pp. 1641-1649 ◽  
Author(s):  
Yanwu Li ◽  
Gang Chen ◽  
Jun-Yao Wang ◽  
Tongtong Zou ◽  
Lan Liu ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Rna Binding ◽  
Intestinal Epithelial Cells ◽  
Binding Protein ◽  
Low Density Lipoprotein ◽  
Rna Binding Protein ◽  
Density Lipoprotein ◽  
Transcriptional Level ◽  
Intestinal Epithelial ◽  
Repressive Effect

MicroRNAs (miRNAs) control gene expression by binding to their target mRNAs for degradation and/or translation repression and are implicated in many aspects of cellular physiology. Our previous study shows that miR-29b acts as a biological repressor of intestinal mucosal growth, but its exact downstream targets remain largely unknown. In the present study, we found that mRNAs, encoding Wnt co-receptor LRP6 (low-density lipoprotein-receptor-related protein 6) and RNA-binding protein (RBP) HuR, are novel targets of miR-29b in intestinal epithelial cells (IECs) and that expression of LRP6 and HuR is tightly regulated by miR-29b at the post-transcriptional level. miR-29b interacted with both Lrp6 and HuR mRNAs via their 3′-UTRs and inhibited LRP6 and HuR expression by destabilizing Lrp6 and HuR mRNAs and repressing their translation. Studies using heterologous reporter constructs revealed a greater repressive effect of miR-29b through a single binding site in the Lrp6 or HuR 3′-UTR, whereas deletion mutation of this site prevented miR-29b-induced repression of LRP6 and HuR expression. Repression of HuR by miR-29b in turn also contributed to miR-29b-induced LRP6 inhibition, since ectopic overexpression of HuR in cells overexpressing miR-29b restored LRP6 expression to near normal levels. Taken together, our results suggest that miR-29b inhibits expression of LRP6 and HuR post-transcriptionally, thus playing a role in the regulation of IEC proliferation and intestinal epithelial homoeostasis.

scholarly journals Transcriptional regulation of importin-α1 by JunD modulates subcellular localization of RNA-binding protein HuR in intestinal epithelial cells

2016 ◽  
Vol 311 (6) ◽  
pp. C874-C883 ◽  
Author(s):  
Yan Xu ◽  
Jie Chen ◽  
Lan Xiao ◽  
Hee Kyoung Chung ◽  
Yuan Zhang ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Subcellular Localization ◽  
Rna Binding ◽  
Nuclear Translocation ◽  
Intestinal Epithelial Cells ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Intestinal Epithelial ◽  
Mucosal Regeneration ◽  
Importin Α

The RNA-binding protein HuR is crucial for normal intestinal mucosal regeneration by modulating the stability and translation of target mRNAs, but the exact mechanism underlying HuR trafficking between the cytoplasm and nucleus remains largely unknown. Here we report a novel function of transcription factor JunD in the regulation of HuR subcellular localization through the control of importin-α1 expression in intestinal epithelial cells (IECs). Ectopically expressed JunD specifically inhibited importin-α1 at the transcription level, and this repression is mediated via interaction with CREB-binding site that was located at the proximal region of importin-α1 promoter. Reduction in the levels of importin-α1 by JunD increased cytoplasmic levels of HuR, although it failed to alter whole cell HuR levels. Increased levels of endogenous JunD by depleting cellular polyamines also inhibited importin-α1 expression and increased cytoplasmic HuR levels, whereas JunD silencing rescued importin-α1 expression and enhanced HuR nuclear translocation in polyamine-deficient cells. Moreover, importin-α1 silencing protected IECs against apoptosis, which was prevented by HuR silencing. These results indicate that JunD regulates HuR subcellular distribution by downregulating importin-α1, thus contributing to the maintenance of gut epithelium homeostasis.

scholarly journals Genomic Analyses of the RNA-binding Protein Hu Antigen R (HuR) Identify a Complex Network of Target Genes and Novel Characteristics of Its Binding Sites

2011 ◽  
Vol 286 (43) ◽  
pp. 37063-37066 ◽  
Author(s):  
Philip J. Uren ◽  
Suzanne C. Burns ◽  
Jianhua Ruan ◽  
Kusum K. Singh ◽  
Andrew D. Smith ◽  
...  
Keyword(s):  
Complex Network ◽  
Binding Sites ◽  
Target Genes ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Genomic Analyses ◽  
Hu Antigen R
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