Vitamin D3 receptor (VDR) expression in HC-11 mammary cells:: regulation by growth-modulatory agents, differentiation, and Ha-ras transformation
Vitamin D3 receptor (VDR) expression in HC-11 mammary cells:: regulation by growth-modulatory agents, differentiation, and Ha-ras transformation
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DOI：
10.1023/a:1006198107805
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发表时间：
1999-03-01
影响因子：
3.8
通讯作者：
Brentani, MM
中科院分区：
文献类型：
--
作者：
Escaleira, MTF;Brentani, MM
来源于中期妊娠BALB/c小鼠的HC-11乳腺上皮细胞经表皮生长因子(EGF)或碱性成纤维细胞生长因子(FGF)处理后，再经乳源性激素刺激(地塞米松、胰岛素和催乳素-DIP)后，可以在培养中分化。在我们的研究中，Northern分析或流式细胞仪检测到HC-11细胞显示出特异性的维生素D-3受体(VDR)，10 NM维生素D-3处理后表现出强烈的生长抑制，停滞在G0/G1期而没有明显的凋亡迹象，VDR基因表达减少，但表达VDR蛋白的细胞比例保持不变。为了验证细胞的生长状态和VDR水平之间是否存在相关性，我们研究了生长调节剂如EGF/bFGF和Ha-ras的融合和转化的影响。Ha-ras转化HC-11细胞后，VDR表达下调，使细胞对维生素D-3的生长抑制作用减敏。表皮生长因子或碱性成纤维细胞生长因子使亲代细胞VDR减少，EGF拮抗维生素D-3的抗增殖作用。同样，从增殖状态到融合状态的转变仅在亲本细胞中显著降低了VDR水平。DIP诱导的HC-11细胞分化(由β-酪蛋白转录本监测)，虽然导致细胞周期停滞，但VDR mRNA含量增加，这似乎更多地与乳源激素诱导有关，而不是分化本身。事实上，在没有EGF预处理的情况下，DIP刺激的HC-11细胞或经DIP处理的HC-11ras培养物，即使在没有分化的情况下，也显示出VDR水平的上调。结论：乳腺VDR水平可能受生长调节剂、腺体生理条件和ras介导的恶性转化的调节。
HC-11 mammary epithelial cells which originate from midpregnant BALB/c mice are able to differentiate in culture after epidermal (EGF) or basic fibroblast (FGF) growth factor pretreatment followed by lactogenic hormone stimulation (Dexamethasone, Insulin, and Prolactin - DIP). In our study, HC-11 cells exhibited specific vitamin D-3 receptors (VDR) determined by Northern analysis or flow cytometry and responded to 10 nM vitamin D-3 treatment displaying strong growth inhibition, arrest in G0/G1 phase without evidence of apoptosis, and VDR mRNA reduction, although the percentage of cells expressing VDR protein remained unchanged. In an attempt to verify if there was a correlation between the growth state of the cells and VDR levels, we have examined the effects of growth modulators such as EGF/bFGF and confluency and transformation by Ha-ras. A down-regulation of VDR expression was observed after Ha-ras transformation of HC-11 cells which desensitized the cells to the growth inhibitory effects of vitamin D-3. EGF or bFGF decreased VDR in parental cells and EGF antagonized the antiproliferative activity of vitamin D-3. As well, transition from proliferating to confluent state significantly reduced VDR levels only in parental cells. DIP-induced HC-11 cell differentiation (monitored by beta-casein transcripts), although leading to cell cycle arrest, increased VDR mRNA content, which seems to be rather related to lactogenic hormone induction than to differentiation itself. In fact, DIP-stimulated HC-11 cells in the absence of EGF pretreatment, or DIP-treated HC-11ras cultures, also displayed up-regulated VDR level even in the absence of differentiation. Concluding, mammary VDR levels might be regulated by growth modulating agents, by physiological conditions of the gland, and by the ras-mediated malignant transformation.