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Molecular targets of 1,25(OH)2D3 in HC11 normal mouse mammary cell line
Maria Lucia Hirata Katayama1, Fátima Solange Pasini, Maria Aparecida Azevedo Koike Folgueira
1Disciplina de Oncologia do Departamento de Radiologia da Faculdade de Medicina da Universidade de São Paulo, Av. Dr. Arnaldo 455, 01246-903, São Paulo, Brazil.
Abstract:
Our aim was to determine the molecular targets involved in the antiproliferative effects of 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), in a normal murine mammary epithelial cell line, HC11. Among the early response genes analyzed, c-myc, junB, junD, c-jun, c-fos, fosB, fra, as well as max, mad1-4, sin3, only c-jun and fra-2 mRNAs were up-regulated after 1,25(OH)(2)D(3) exposure. Cyclin C was reduced and cyclin A2 and E were slightly enhanced; however, cyclins D1, D3, B1, B2, F, G1, G2, I and H, as well as TGF beta 1, TGF beta 3, T beta RI and T beta RII transcripts were not modulated by 1,25(OH)(2)D(3). Although p27(KIP1) protein content was unchanged, enhancement of p21(WAF1/CIP1) low basal levels in cell extracts and IGFBP-3 abundance on the culture medium was detected after 1,25(OH)(2)D(3) induction. Using differential display analysis, we identified eight down-modulated clones in exposed cells: 26S proteasome non-ATPase subunit Pad1, ubiquitin-conjugating enzyme Ube2i, extracellular proteinase inhibitor Expi or Wdnm1, cytochrome-c oxidase Cox7c, microtubule-associated protein-1 light chain-3 (Map1lc3), nascent-associated complex alpha Naca, transforming acidic coiled-coil Tacc3, stearoyl-CoA desaturase (Scd), keratin 6 alpha, and 1 up-regulated, fork head transcription factor Hfh-1L. Hence, the antiproliferative effect of 1,25(OH)(2)D(3) seems associated to enhancement of c-jun, Fra-2, IGFBP3 and p21(WAF1/CIP1). Decreased Pad1 and Ube2i might account for increased stability of cell cycle inhibitory proteins while reduced Wdnm1, Tacc3 and Scd might be secondary to accumulation of cells in G0/G1 phase.
Insights
1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) inhibits mammary cell proliferation by upregulating c-jun, Fra-2, IGFBP3, and p21(WAF1/CIP1). This vitamin D metabolite also downregulates Pad1 and Ube2i, potentially stabilizing cell cycle inhibitors.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) is a biologically active form of vitamin D.
- Vitamin D plays a role in cell proliferation and differentiation.
- Understanding the molecular mechanisms of 1,25(OH)(2)D(3) is crucial for its therapeutic applications.
Purpose of the Study:
- To identify the molecular targets responsible for the antiproliferative effects of 1,25(OH)(2)D(3) in HC11 murine mammary epithelial cells.
- To elucidate the gene expression changes induced by 1,25(OH)(2)D(3) treatment.
Main Methods:
- Cell culture of HC11 murine mammary epithelial cells.
- Treatment with 1,25(OH)(2)D(3).
- Analysis of gene and protein expression using techniques like differential display and Western blotting.
Main Results:
- Upregulation of c-jun and Fra-2 mRNA, p21(WAF1/CIP1) protein, and IGFBP-3.
- Downregulation of 26S proteasome subunit Pad1 and ubiquitin-conjugating enzyme Ube2i.
- Modulation of specific cyclins and other identified genes, including Wdnm1, Tacc3, and Scd.
Conclusions:
- The antiproliferative effect of 1,25(OH)(2)D(3) is associated with the upregulation of c-jun, Fra-2, IGFBP3, and p21(WAF1/CIP1).
- Decreased expression of Pad1 and Ube2i may contribute to increased stability of cell cycle inhibitory proteins.
- Reduced Wdnm1, Tacc3, and Scd expression may result from cell cycle arrest in the G0/G1 phase.