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Epigenetic regulation of vitamin D metabolism in human lung adenocarcinoma.
- Source :
-
Journal of thoracic oncology : official publication of the International Association for the Study of Lung Cancer [J Thorac Oncol] 2014 Apr; Vol. 9 (4), pp. 473-82. - Publication Year :
- 2014
-
Abstract
- Introduction: 1α,25-Dihydroxyvitamin D3 (1,25-D3) is antiproliferative in preclinical models of lung cancer, but in tumor tissues, its efficacy may be limited by CYP24A1 expression. CYP24A1 is the rate limiting catabolic enzyme for 1,25-D3 and is overexpressed in human lung adenocarcinoma (AC) by unknown mechanisms.<br />Methods: The DNA methylation status of CYP24A1 was determined by bisulfite DNA pyrosequencing in a panel of 30 lung cell lines and 90 surgically resected lung AC. The level of CYP24A1 methylation was correlated with CYP24A1 expression in lung AC cell lines and tumors. In addition, histone modifications were assessed by quantitative chromatin immunoprecipitation-polymerase chain reaction (ChIP-qPCR) in A549, NCI-H460, and SK-LU-1.<br />Results: Bisulfite DNA pyrosequencing analysis revealed that CYP24A1 gene was heterogeneously methylated in lung AC. Expression of CYP24A1 was inversely correlated with promoter DNA methylation in lung AC cell lines and tumors. Treatment with 5-aza-2'-deoxycytidine (5-Aza) and trichostatin A (TSA) increased CYP24A1 expression in lung AC. We observed that CYP24A1 promoter hypermethylation decreased CYP24A1 enzyme activity in vitro, whereas treatment with 5-Aza and/or TSA increased CYP24A1 enzyme affinity for its substrate 1,25-D3. In addition, ChIP-qPCR analysis revealed specific histone modifications within the CYP24A1 promoter region. Treatment with TSA increased H3K4me2 and H3K9ac and simultaneously decreased H3K9me2 at the CYP24A1 promoter and treatment with 5-Aza and/or TSA increased the recruitment of vitamin D receptor (VDR) to vitamin D response elements (VDRE) of the CYP24A1 promoter.<br />Conclusions: The expression of CYP24A1 gene in human lung AC is in part epigenetically regulated by promoter DNA methylation and repressive histone modifications. These findings should be taken into consideration when targeting CYP24A1 to optimize antiproliferative effects of 1,25-D3 in lung AC.
- Subjects :
- Adenocarcinoma metabolism
Adenocarcinoma mortality
Aged
Blotting, Western
Chromatin Immunoprecipitation
DNA Methylation
Enzyme-Linked Immunosorbent Assay
Female
Flow Cytometry
Follow-Up Studies
Humans
Lung Neoplasms metabolism
Lung Neoplasms mortality
Male
Neoplasm Recurrence, Local metabolism
Neoplasm Recurrence, Local mortality
Neoplasm Staging
Prognosis
Promoter Regions, Genetic genetics
RNA, Messenger genetics
Real-Time Polymerase Chain Reaction
Receptors, Calcitriol genetics
Receptors, Calcitriol metabolism
Reverse Transcriptase Polymerase Chain Reaction
Survival Rate
Tumor Cells, Cultured
Vitamin D metabolism
Vitamin D3 24-Hydroxylase metabolism
Adenocarcinoma genetics
Epigenesis, Genetic
Gene Expression Regulation, Neoplastic
Lung Neoplasms genetics
Neoplasm Recurrence, Local genetics
Vitamin D analogs & derivatives
Vitamin D3 24-Hydroxylase genetics
Subjects
Details
- Language :
- English
- ISSN :
- 1556-1380
- Volume :
- 9
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- Journal of thoracic oncology : official publication of the International Association for the Study of Lung Cancer
- Publication Type :
- Academic Journal
- Accession number :
- 24736069
- Full Text :
- https://doi.org/10.1097/JTO.0000000000000114