We have located links that may give you full text access.
Journal Article
Review
Epigenetic corruption of VDR signalling in malignancy.
Anticancer Research 2006 July
BACKGROUND: The ligand-mediated switch from binding co-repressor to co-activator complexes is central to the transcriptional actions of the vitamin D receptor (VDR) and other nuclear receptors. The capacity of deregulated co-repressors to attenuate the responsiveness of VDR signalling in cancer models was examined.
MATERIALS AND METHODS: Proliferation and gene regulation studies were undertaken in non-malignant and malignant cell line and primary models.
RESULTS: Both primary tissue models and cancer cell lines displayed a spectrum of suppressed responsiveness towards 1alpha, 25 hydroxy vitamin D3 (1alpha25(OH)2D3) which correlated with elevated co-repressor content: specifically, elevated silencing mediator of retinoid and thyroid hormone receptors/nuclear co-repressor 2 (NCoR2/SMRT) in prostate cancer cell lines and primary tumour cultures, and elevated nuclear receptor co-repressor 1 (NCoR1) in breast cancer cell lines. Interestingly, whilst the cancer cell lines frequently also displayed reduced VDR content, the primary tumour material retained and/or elevated VDR mRNA, correlated with co-repressor content. Functional approaches towards NCoR2/SMRT (siRNA) in prostate cancer cells or NCoR1 (overexpression) in non-malignant breast epithelial cells confirmed a role in suppressing VDR transcriptional and cellular actions. Targeted co-treatments of 1alpha25(OH)2D3 plus HDAC inhibitors (TSA, NaB) resulted in re-expression of antiproliferative target genes (e.g., GADD45alpha, p21(waf1/cip1)) and synergistic inhibition of proliferation.
CONCLUSION: These data suggest that VDR actions in solid tumours are retained, but were skewed by epigenetic mechanisms to suppress selectively antiproliferative target gene promoter responses. This molecular lesion provides a novel chemotherapy target for acceptable doses of 1alpha25(OH)2D3 plus HDAC inhibitors.
MATERIALS AND METHODS: Proliferation and gene regulation studies were undertaken in non-malignant and malignant cell line and primary models.
RESULTS: Both primary tissue models and cancer cell lines displayed a spectrum of suppressed responsiveness towards 1alpha, 25 hydroxy vitamin D3 (1alpha25(OH)2D3) which correlated with elevated co-repressor content: specifically, elevated silencing mediator of retinoid and thyroid hormone receptors/nuclear co-repressor 2 (NCoR2/SMRT) in prostate cancer cell lines and primary tumour cultures, and elevated nuclear receptor co-repressor 1 (NCoR1) in breast cancer cell lines. Interestingly, whilst the cancer cell lines frequently also displayed reduced VDR content, the primary tumour material retained and/or elevated VDR mRNA, correlated with co-repressor content. Functional approaches towards NCoR2/SMRT (siRNA) in prostate cancer cells or NCoR1 (overexpression) in non-malignant breast epithelial cells confirmed a role in suppressing VDR transcriptional and cellular actions. Targeted co-treatments of 1alpha25(OH)2D3 plus HDAC inhibitors (TSA, NaB) resulted in re-expression of antiproliferative target genes (e.g., GADD45alpha, p21(waf1/cip1)) and synergistic inhibition of proliferation.
CONCLUSION: These data suggest that VDR actions in solid tumours are retained, but were skewed by epigenetic mechanisms to suppress selectively antiproliferative target gene promoter responses. This molecular lesion provides a novel chemotherapy target for acceptable doses of 1alpha25(OH)2D3 plus HDAC inhibitors.
Full text links
Related Resources
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app
All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.
By using this service, you agree to our terms of use and privacy policy.
Your Privacy Choices
You can now claim free CME credits for this literature searchClaim now
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app