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目的： 研究１，２５－二羟维生素Ｄ３ 对结肠癌细胞系Ｃａｃｏ－２ 细胞中报告基因表达的作用，并探讨在报告载体ｐＧＬ２ 序列中存在潜在的抑制性维生素Ｄ应答元件（ＶＤＲＥ）的可能性。方法： 采用磷酸钙沉淀法将报告载体转染入Ｃａｃｏ－２ 细胞。Ｃａｃｏ－２细胞经不同浓度１，２５－二羟维生素Ｄ３ 处理后测定细胞裂解液中表达的荧光素酶活性。结果： 应用ｐＧＬ２ 报告载体时，当用ｐＳＧ５－ＶＤＲ表达载体共转染后，１，２５－二羟维生素Ｄ３显著地抑制Ｃａｃｏ－２ 细胞荧光素酶的表达（Ｐ＜ ０．０５）；而未使用该表达载体共转染则无抑制作用（Ｐ＞ ０．０５）。应用ｐＧＬ３ 报告载体时，不同浓度的１，２５－二羟维生素Ｄ３ 对ｐＬＧ３转染后Ｃａｃｏ－２ 细胞表达的荧光素酶活性均无显著抑制作用（Ｐ＞ ０．０５），该作用不依赖是否存在有ｐＳＧ５－ＶＤＲ表达载体共转染。结论：１，２５－二羟维生素Ｄ３ 对报告载体ＰＧＬ２ 荧光素酶表达具有抑制作用，而对ｐＧＬ３ 则否；类似人类ＰＴＨ基因中的潜在抑制性ＶＤＲＥ存在于报告载体ｐＧＬ２，在ｐＧＬ３ 中该ＶＤＲＥ业已改变。
OBJECTIVE: To investigate the effect of 1,25-dihydroxyvitamin D3 on the reporter gene expression in colon cancer cell line Caco-2 and to explore the possibility of a potentially inhibitory vitamin D response element (VDRE) in the reporter vector pGL2 sequence . Methods: The reporter vector was transfected into Caco-2 cells by calcium phosphate precipitation method. The luciferase activity expressed in cell lysates was determined after Caco-2 cells were treated with various concentrations of 1,25-dihydroxyvitamin D3. Results: When pGL2 reporter vector was used, 1,25-dihydroxyvitamin D3 significantly inhibited luciferase expression in Caco-2 cells (P <0.05) when co-transfected with pSG5-VDR expression vector; however, Co-transfection with this expression vector did not inhibit (P> 0.05). When pGL3 reporter vector was used, different concentrations of 1,25-dihydroxyvitamin D3 had no significant inhibitory effect on the luciferase activity of Caco-2 cells transfected with pLG3 (P> 0.05), which was independent of whether There pSG5-VDR expression vector co-transfection. Conclusion: 1,25-dihydroxyvitamin D3 can inhibit the expression of PGL2 luciferase but not pGL3. Potential inhibitory VDRE in human-like PTH gene exists in reporter vector pGL2, which has been reported in pGL3 change.