The vitamin D receptor (VDR) and its ligand 1,25(OH)2D3 (1,25D) impact differentiation and exert anti-tumor effects in many tissues, but its role in salivary gland has yet to be defined. Using immunohistochemistry (IHC), we have detected strong VDR expression in murine and human salivary gland ducts. Compared to normal gland, VDR protein expression was retained in differentiated human pleomorphic adenoma (PA) but was undetectable in undifferentiated PA and in carcinomas, suggesting deregulation of VDR during salivary cancer progression. To gain insight into the potential role of VDR in salivary cancer, we assessed the effects of vitamin D in vivo and in vitro. Despite the presence of VDR in salivary gland, chronic dietary vitamin D restriction did not alter morphology of the salivary epithelium in C57/Bl6 mice. The localization of VDR in ductal epithelium prompted us to examine the effects of 1,25D in an established cell line (mSGc) derived from normal murine submandibular gland (SMG). This previously characterized cell line consists of multiple stem, progenitor and differentiated cell types as determined by mutually exclusive cellular expression of basal, ductal and myoepithelial markers. We demonstrated VDR expression and regulation of VDR target genes Vdr and Postn by 1,25D in mSGc, indicating functional ligand-mediated transcriptional activity. The effect of VDR signaling on epithelial differentiation markers was assessed by qPCR and IHC in mSGc cells treated with 1,25D. We found that 1,25D reduced mRNA expression of the basal cell progenitor marker keratin 5 (K5) and increased expression of the differentiated ductal cell marker keratin 7 (K7). Further, we found that 1,25D significantly decreased the number of proliferating cells, including proliferating K5+ cells. Characterization of cell cycle by Muse cytometry indicated 1,25D treatment decreased cells in S, G2, and M phase. The inhibition of K5+ cell proliferation by 1,25D is of particular interest because K5+ basal cells contribute to a wide variety of salivary tumor types. Our studies suggest that 1,25D alters cancer-relevant progenitor and differentiation markers in the salivary gland.

中文翻译：

---

唾液腺稳态和癌症中的VDR。

维生素D受体（VDR）及其配体1,25（OH）2D3（1,25D）影响分化并在许多组织中发挥抗肿瘤作用，但其在唾液腺中的作用尚未确定。使用免疫组织化学（IHC），我们已经检测到鼠和人唾液腺导管中强烈的VDR表达。与正常腺体相比，VDR蛋白的表达在分化的人多形性腺瘤（PA）中得以保留，但在未分化的PA和癌症中则无法检测到，这表明唾液腺癌进展过程中VDR的调节异常。为了深入了解VDR在涎腺癌中的潜在作用，我们评估了维生素D在体内和体外的作用。尽管唾液腺中存在VDR，但慢性饮食中的维生素D限制并未改变C57 / B16小鼠唾液上皮的形态。VDR在导管上皮中的定位促使我们研究了1,25D在源自正常鼠下颌下腺（SMG）的已建立细胞系（mSGc）中的作用。这种先前表征的细胞系由多个干细胞，祖细胞和分化的细胞类型组成，这是由基础，导管和肌上皮标志物的互斥细胞表达确定的。我们证明了mDRc中1,25D的VDR表达和VDR目标基因Vdr和Postn的调控，表明功能性配体介导的转录活性。通过qPCR和IHC在1,25D处理的mSGc细胞中评估了VDR信号转导对上皮分化标志物的影响。我们发现1,25D减少了基底细胞祖细胞标记角蛋白5（K5）的mRNA表达，并增加了分化导管细胞标记角蛋白7（K7）的表达。此外，我们发现1,25D显着减少了增殖细胞（包括增殖K5 +细胞）的数量。通过缪斯细胞计数法表征细胞周期表明1,25D处理可减少S，G2和M期细胞。1,25D对K5 +细胞增殖的抑制作用特别令人关注，因为K5 +基底细胞可导致多种唾液肿瘤类型。我们的研究表明1,25D改变了唾液腺中与癌症相关的祖细胞和分化标记。25D特别令人感兴趣，因为K5 +基底细胞可导致多种唾液肿瘤类型。我们的研究表明1,25D改变了唾液腺中与癌症相关的祖细胞和分化标记。25D特别令人感兴趣，因为K5 +基底细胞可导致多种唾液肿瘤类型。我们的研究表明1,25D改变了唾液腺中与癌症相关的祖细胞和分化标记。