Xue Meilan, Ge Yinlin, Zhang Jinyu, Wang Qing, Hou Lin
Department of Biochemistry and Molecular Biology, Medical College, Qingdao University, Qingdao, Shandong, China.
Braz J Med Biol Res. 2012 Dec;45(12):1141-9. doi: 10.1590/s0100-879x2012007500145. Epub 2012 Sep 11.
Chlorella vulgaris has the gene of n-3 fatty acid desaturase (CvFad3), which can synthesize the precursor of n-3 polyunsaturated fatty acids (PUFAs) or convert n-6 to n-3 PUFAs. The objective of the present study was to examine whether the CvFad3 gene from C. vulgaris can be functionally and efficiently expressed in human breast cancer cells and whether its expression can exert a significant effect on cell fatty acid composition. We inserted the CvFad3 gene into the plasmid pEGFP-C3 to construct the eukaryotic expression vector pEGFP-C3-n-3 and to express the n-3 Fad gene in human breast cancer cells (MCF-7 cells). Transfection of MCF-7 cells with the recombinant vector resulted in a high expression of n-3 fatty acid desaturase. Lipid analysis indicated that the ratio of n-6/n-3 PUFAs was decreased from 6:1 in the control cells to about 1:1 in the cells expressing the n-3 fatty acid desaturase. Accordingly, the CvFad3 gene significantly decreased the ratio of n-6/n-3 PUFAs of the MCF-7 cell membrane. The expression of the CvFad3 gene can decrease cell proliferation and promote cell apoptosis. This study demonstrates that the CvFad3 gene can dramatically balance the ratio of n-6/n-3 PUFAs and may provide an effective approach to the modification of the fatty acid composition of mammalian cells, also providing a basis for potential applications of its transfer in experimental and clinical settings.
普通小球藻具有n-3脂肪酸去饱和酶（CvFad3）基因，该基因可合成n-3多不饱和脂肪酸（PUFAs）的前体或将n-6转化为n-3 PUFAs。本研究的目的是检测来自普通小球藻的CvFad3基因是否能在人乳腺癌细胞中实现功能性高效表达，以及其表达是否会对细胞脂肪酸组成产生显著影响。我们将CvFad3基因插入质粒pEGFP-C3中，构建真核表达载体pEGFP-C3-n-3，并在人乳腺癌细胞（MCF-7细胞）中表达n-3 Fad基因。用重组载体转染MCF-7细胞导致n-3脂肪酸去饱和酶的高表达。脂质分析表明，n-6/n-3 PUFAs的比例从对照细胞中的6:1降至表达n-3脂肪酸去饱和酶的细胞中的约1:1。因此，CvFad3基因显著降低了MCF-7细胞膜的n-6/n-3 PUFAs比例。CvFad3基因的表达可降低细胞增殖并促进细胞凋亡。本研究表明，CvFad3基因可显著平衡n-6/n-3 PUFAs的比例，可能为修饰哺乳动物细胞脂肪酸组成提供一种有效方法，也为其在实验和临床环境中的转移潜在应用提供依据。
