Batth B K, Tripathi R, Srinivas U K
Centre for Cellular and Molecular Biology, Hyderabad, India.
Differentiation. 2001 Sep;68(2-3):133-40. doi: 10.1046/j.1432-0436.2001.680207.x.
Curcumin, a natural component of turmeric extracted from the rhizomes of Curcuma longa, is known to exhibit a number of biological properties. In the present study, curcumin, at low concentration, was shown to induce differentiation in embryonal carcinoma cell line PCC4. In response to curcumin, PCC4 cells ceased to proliferate and showed cell cycle arrest at G1 phase after 4 hours of treatment, followed by their differentiation which is characterized by increase of nuclear/cytoplasmic ratio. The expression of hsp 70 was also seen upon 8 h of curcumin treatment, and it remained constant up to 48 h. Differentiated cells also expressed a series of differentiation markers such as lamin A, well-established actin, and keratin cytoskeleton. We used mRNA differential display analysis to identify the genes that are regulated during curcumin-induced differentiation of PCC4 cells. We cloned and sequenced three partial cDNAs that were differentially expressed in normal and differentiated cells. Sequence comparison of one downregulated cDNA (Al) has shown homology to a gene present on mouse chromosome five, while the two upregulated cDNA (C1 and C7) are homologous to several mouse ESTs clones from organs of mesodermal origin. We have identified the full-length coding sequence of the Cl fragment with a putative amino acid sequence. Tissue-specific Northern with RNA from adult mouse organs with the C1 fragment alone showed hybridization with mRNA from several tissues, whereas the same Northern with only the coding sequence showed expression of C1 gene mainly in the adult kidney. Homology search revealed that C1 sequence is part of the 3' UTR and may be common to several genes expressed in many tissues. Thus, curcumin appears to differentiate embryonal carcinoma cell PCC4, and one of the upregulated genes seems to be expressed mainly in the adult kidney.
姜黄素是从姜黄根茎中提取的一种天然成分，已知具有多种生物学特性。在本研究中，低浓度的姜黄素可诱导胚胎癌细胞系PCC4分化。在姜黄素的作用下，PCC4细胞停止增殖，处理4小时后细胞周期停滞在G1期，随后开始分化，其特征是核质比增加。姜黄素处理8小时后还可见热休克蛋白70（hsp 70）的表达，并且在48小时内保持恒定。分化的细胞还表达了一系列分化标志物，如核纤层蛋白A、成熟的肌动蛋白和角蛋白细胞骨架。我们使用mRNA差异显示分析法来鉴定在姜黄素诱导PCC4细胞分化过程中被调控的基因。我们克隆并测序了在正常细胞和分化细胞中差异表达的三个部分cDNA。一个下调的cDNA（Al）的序列比较显示与小鼠5号染色体上的一个基因具有同源性，而两个上调的cDNA（C1和C7）与来自中胚层起源器官的几个小鼠EST克隆同源。我们已经鉴定出具有推定氨基酸序列的C1片段的全长编码序列。仅用C1片段对成年小鼠器官的RNA进行组织特异性Northern杂交显示与多个组织的mRNA杂交，而仅用编码序列进行的相同Northern杂交显示C1基因主要在成年肾脏中表达。同源性搜索显示C1序列是3'非翻译区的一部分，可能是许多组织中表达的几个基因所共有的。因此，姜黄素似乎能使胚胎癌细胞PCC4分化，并且上调的基因之一似乎主要在成年肾脏中表达。
