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1 January 2004 Cadmium Stimulates Transcription of the Cytochrome P450 Side Chain Cleavage Gene in Genetically Modified Stable Porcine Granulosa Cells
Andrea D. Smida, Ximena P. Valderrama, Maria C. Agostini, Michael A. Furlan, Jorge Chedrese
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Abstract

We investigated the effects of cadmium (Cd2 ) on transcription of the cytochrome P450 side chain cleavage (P450scc) gene and on progesterone synthesis in stable granulosa cells. We used the stable porcine granulosa cell line, JC-410, genetically modified to express a luciferase genomic construct carrying 2320 base pairs (bp) of the P450scc gene promoter (P450scc-2320-LUC). A construct containing only the luciferase gene, pOLUC, was used as a promoterless control. At 1 μM, cadmium chloride (CdCl2) increased transient expression of P450scc-2320-LUC in JC-410 cells by 2.6-fold after 24-h incubation. A similar pattern of stimulation by CdCl2 was observed in cells transiently transfected with a luciferase genomic construct carrying 100 bp of the P450scc gene promoter P450scc-100-LUC, whereas no stimulation by CdCl2 was observed in cells transfected with pOLUC. At 0.6, 1, and 2 μM, CdCl2 stimulated the activity of the P450scc-2320-LUC promoter in a dose-related fashion by 1.58-, 3.19-, and 2.67-fold, respectively, after 24-h incubation. Northern blot analysis showed that CdCl2 at 0.1, 1, 2, and 3 μM increased P450scc mRNA levels by 3.13-, 1.38-, 1.61-, and 1.57-fold, respectively, after 24-h incubation. After 48-h incubation, CdCl2 at 0.6, 1, and 2 μM further increased P450scc mRNA levels by 3.43-, 2.08-, and 2.4-fold, respectively. At 1, 2, and 3 μM, CdCl2 inhibited progesterone synthesis to 0.48-, 0.38-, and 0.29-fold, respectively. After 48-h incubation, CdCl2 at 0.1 μM stimulated progesterone synthesis by 1.6-fold. We conclude that Cd2 has a dual action in stable porcine granulosa cells: Low concentrations activate, whereas high concentrations inhibit, expression of the P450scc gene and progesterone synthesis. The stimulatory effect of Cd2 appears to be mediated via a cis-acting element located 100 bp upstream of the P450scc gene transcription start site.

Andrea D. Smida, Ximena P. Valderrama, Maria C. Agostini, Michael A. Furlan, and Jorge Chedrese "Cadmium Stimulates Transcription of the Cytochrome P450 Side Chain Cleavage Gene in Genetically Modified Stable Porcine Granulosa Cells," Biology of Reproduction 70(1), 25-31, (1 January 2004). https://doi.org/10.1095/biolreprod.103.019000
Received: 5 May 2003; Accepted: 1 August 2003; Published: 1 January 2004
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KEYWORDS
gene regulation
granulosa cells
progesterone
steroid hormones
toxicology
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