Regulation of metallothionein gene expression by 1 alpha,25-dihydroxyvitamin D3 in cultured cells and in mice.

Abstract

la,25-Dihydroxyvitamin D3 [la,25(OH)2D31, a hormonally active form of vitamin D3, has been shown to modulate cell differentiation and tumor promotion. This report demonstrates that mRNA of the metallothionein (MT) gene was induced by la,25(OH)2D3 in cultured epidermal keratinocytes and also in liver, kidney, and skin tissues when la-hydroxyvitamin D3, a synthetic precursor of lai,25(OH)2D3, was applied in vivo. Exposure of FRSK cells, a cell line derived from fetal -at skin keratinocytes, to la,25(OH)2D3 at 5 ng/ml (12 nM) increased MT mRNA to almost the same extent as that induced by 10 jcM dexamethasone or 1 ,LM CdCl2. This increase in the level of MT mRNA was evident within 2 hr and was maximal 12-24 hr after the addition of la,25(OH)2D3. (9). Furthermore, we found that la,25(OH)2D3 inhibited tumor promotion by phorbol 12-O-tetradecanoate 13-acetate (TPA) and mezerein in mouse skin (10). It also inhibited induction of ornithine decarboxylase by tumor promoters in the skin, stomach, colon, and liver (11, 12). In cell culture systems, however, this hormone was found to enhance chemical transformation of BALB 3T3 (13,14) and Syrian hamster cells (15) and also to induce anchorage-independent growth of JB6 (16), BALB 3T3, and NIH 3T3 (17) cells. The apparent discrepancy between its effects on tumor promotion in vitro and in vivo requires further study, especially at the molecular level.Identification of genes that are regulated by la,25(0H)2D3 and the mechanisms of its regulatory effect are of particular importance. Calcium binding protein was shown to be induced in rat intestine by la,25(0H)2D3 (18). DeLuca and his colleagues (19) reported that four distinct mRNAs were significantly increased in rat intestine when la,25(0H)2D3 was applied to vitamin D-deficient animals: these were vitamin D-dependent calcium-binding protein, mitochondrial ATP synthetase, and cytochrome oxidase subunits I and III. We found (17) that la,25(OH)2D3 induced expression of the c-Ki-ras gene in BALB 3T3 and NIH 3T3 cells.In this study, we found that mRNA of the MT gene was induced by la,25(0H)2D3 in cultured epidermal keratinocytes and also in liver, kidney, and skin tissues when la-hydroxyvitamin D3 [la(OH)D3], a synthetic precursor of la,25(OH)2D3, was applied in vivo. This induction of MTs may be relevant to some biological actions of la,25(OH)2D3. la(OH)D3, la-hydroxyvitamin D3. §To whom all correspondence should be addressed. MATERIALS AND METHODS 8810The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.

Molecular pathways involved in the anti‐apoptotic effect of 1,25‐dihydroxyvitamin D3 in primary human keratinocytes

“…In addition, certain in vitro data support the existence of a protective role of 1,25(OH) 2 D 3 against UVinduced skin cancer. Indeed, it has been shown in keratinocytes that 1,25(OH) 2 D 3 induces metallothionein [Karasawa et al, 1987;De Haes et al, 2004], a radical scavenging protein that protects keratinocytes against oxidativemediated UV-injury [Wang et al, 2004]. Moreover, 1,25(OH) 2 D 3 is said to protect keratinocytes against UVB-induced direct DNAdamage [own unpublished results and Wong et al, 2004].…”

Protective effect of vitamin D3 analogues on endotoxin shock in mice

“…Thus our results suggest that vitamin D 3 analogues improve the survival rate of LPS-treated mice through regulation of the function of macrophages including Kupffer cells. Vitamin D 3 analogues are reported to regulate the gene expression of metallothionein [23] or heat shock protein [24,25]. These proteins are well known to scavenge the free radicals [25,26] and protect some types of cells from oxidative stress.…”

Metallothionein – overexpression as a highly significant prognostic factor in melanoma: a prospective study on 1270 patients

“…As a variety of endogenous factors (e.g. glucocorticosteroids, ILs, IFNg, TNF-a) are involved in the induction of the synthesis of intracellular MT, one may suggest that this may lead to an overprotection of tumour cells against apoptosis, and, on the other hand, supporting the metastatic behaviour of the tumour (Karin et al, 1985;Karasawa et al, 1987;Nath et al, 1988;Schroeder and Cousins, 1990;Sato and Sasaki, 1992;Tsangaris and TzortzatouStathopoulou, 1998;Miles et al, 2000;Nishimura et al, 2000).…”

“…They can protect cells against UV-/ionic radiation (Hansen et al, 1997;Hanada et al, 1998;Reeve et al, 2000) as well as cytotoxic alkylating agents including chemotherapeutics (Chin et al, 1993;Hishikawa et al, 1997;Okazaki et al, 1998;Sunada et al, 2005), modulate oxygen free radicals and nitric oxide and inhibit apoptosis (Tsangaris and Tzortzatou-Stathopoulou, 1998). The synthesis of MT is induced by group II heavy metal ions as well as by endogenous factors such as glucocorticoids, cytokines (interleukin (IL)-1 or IL-6, interferon g (IFNg), tumour necrosis factor a (TNF-a)) or vitamin D 3 (Karin et al, 1985;Karasawa et al, 1987;Schroeder and Cousins, 1990;Sato and Sasaki, 1992;Nishimura et al, 2000). There is also some evidence that inflammatory stressors (e.g.…”