Gene Regulatory Scenarios of Primary 1,25-Dihydroxyvitamin D3 Target Genes in a Human Myeloid Leukemia Cell Line

Abstract

Genome- and transcriptome-wide data has significantly increased the amount of available information about primary 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) target genes in cancer cell models, such as human THP-1 myelomonocytic leukemia cells. In this study, we investigated the genes G0S2, CDKN1A and MYC as master examples of primary vitamin D receptor (VDR) targets being involved in the control of cellular proliferation. The chromosomal domains of G0S2 and CDKN1A are 140–170 kb in size and contain one and three VDR binding sites, respectively. This is rather compact compared to the MYC locus that is 15 times larger and accommodates four VDR binding sites. All eight VDR binding sites were studied by chromatin immunoprecipitation in THP-1 cells. Interestingly, the site closest to the transcription start site of the down-regulated MYC gene showed 1,25(OH)2D3-dependent reduction of VDR binding and is not associated with open chromatin. Four of the other seven VDR binding regions contain a typical DR3-type VDR binding sequence, three of which are also occupied with VDR in macrophage-like cells. In conclusion, the three examples suggest that each VDR target gene has an individual regulatory scenario. However, some general components of these scenarios may be useful for the development of new therapy regimens.

Changes in vitamin D target gene expression in adipose tissue monitor the vitamin D response of human individuals

“…ChIP was carried out following the protocol described earlier . After treatment of SGBS cells, nuclear proteins were cross‐linked to DNA by 10‐min formaldehyde treatment.…”

The transcriptional regulator BCL6 participates in the secondary gene regulatory response to vitamin D

“…Some of the most induced 1,25(OH) 2 D 3 target genes, such as CD14 (43.5-fold), CAMP (38.4-fold), IL8 (9.3-fold), THBD (8.8-fold), SLC37A2 (7.2-fold) and G0S2 (4.3-fold), were already characterized in the context of previous mechanistic studies as primary 1,25(OH) 2 D 3 targets [14,19,21,22,25,38,39]. The fact that the chromosomal domains of these genes contain binding sites for BCL6 suggests a positive feedback loop mechanism for the expression of the genes.…”

The Potential of Vitamin D-Regulated Intracellular Signaling Pathways as Targets for Myeloid Leukemia Therapy

“…Interestingly, it was found that 1,25D binding shifts the locations of VDR occupation to DR3-type response elements that surround its target genes, and there was a large variety of regulatory constellations of VDR binding sites. It is also becoming increasingly clear that VDR binding choices are highly specific for the cell type [ 130 , 131 , 132 ]. The biological significance may be derived from microarray analyses following 1,25D treatment, such as that which found that the monocytic marker CD14 and cathelicidin anti-microbial peptide were by far the most markedly upregulated genes in this scenario [ 131 ].…”

“…The biological significance may be derived from microarray analyses following 1,25D treatment, such as that which found that the monocytic marker CD14 and cathelicidin anti-microbial peptide were by far the most markedly upregulated genes in this scenario [ 131 ]. Among the genes upregulated early, as shown by the microarray analysis, the monocyte-specific genes and metabolism-related genes are two noticeable groups [ 132 ]. The effects of longer exposure to 1,25D include the finding that VDR binding sites are significantly enriched near autoimmune and cancer-associated genes identified from GWA studies [ 133 ].…”