Diversity in the ability of cultured cells to elongate and desaturate essential (n-6 and n-3) fatty acids.
Diversity in the ability of cultured cells to elongate and desaturate essential (n-6 and n-3) fatty acids.
复制标题
培养细胞延长必需（n-6 和 n-3）脂肪酸和使其去饱和能力的多样性。
DOI：
10.1111/j.1749-6632.1994.tb44366.x
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发表时间：
1994
影响因子：
5.2
通讯作者：
Miller,WM
中科院分区：
文献类型：
--
作者：
Grammatikos,SI;Subbaiah,PV;Victor,TA;Miller,WM
必需脂肪酸(EFAs)不能由哺乳动物细胞合成。一旦与饮食一起摄入，它们可以经历去饱和/饱和和链延长/缩短，以产生同一家族的各种多不饱和脂肪酸。来自各种组织的体外细胞能够在不同程度上处理EFA。将母体EFA亚油酸(LA，n-6)和α-亚麻酸(LNA，n-3)转化为20碳多不饱和脂肪酸花生四烯酸(AA，n-6)和二十碳五烯酸(EPA，n-3)，需要延长链长度和脱饱和度。AA和EPA是许多组织发挥最佳生物学功能所必需的，也是具有生物活性的二十烷基类激素的前体。所有培养的细胞都能拉长外源LA和LNA，而且大多数细胞都能进行Delta 5去饱和，因此Delta 6去饱和是AA和EPA产生的限制步骤。与AA或EPA相比，具有更多双键的较长脂肪酸的产生频率较低，原因是Delta4的去饱和能力不足。逆向转化(链缩短)的过程研究较少，但来自各种细胞的证据表明，这种类型的代谢转化通常是活跃的。以MCF-7(人乳腺癌细胞系)和MCF-10A细胞(人非癌性乳腺癌细胞系)为例，强调培养细胞处理EFA能力的差异性。在相同的培养条件下，MCF-10A细胞发生广泛的脱饱和、延长和逆转，而MCF-7细胞只能延长和逆转外源EFA。鉴于培养细胞处理EFA的能力差异很大，在评估该细胞的EFA处理模式之前，无法得出关于外源性EFA对特定细胞影响的机制的结论。
Essential fatty acids (EFAs) cannot be synthesized by mammalian cells. Once taken in with the diet, they can undergo desaturations/saturations and chain elongations/shortenings to yield a variety of polyunsaturated fatty acids of the same family. Cells in vitro from a variety of tissues are capable of processing EFAs to varying extents. Conversion of the parent EFAs, linoleic (LA, n-6) and alpha-linolenic (LNA, n-3) acids, to the 20-carbon polyunsaturated fatty acids, arachidonic (AA, n-6) and eicosapentanoic (EPA, n-3), requires chain elongation and delta 6 and delta 5 desaturations. AA and EPA are required by many tissues for optimal biological function and are precursors of biologically active eicosanoid hormones. All cultured cells are able to elongate exogenous LA and LNA, and most can perform delta 5 desaturation, so delta 6 desaturation is the limiting step in AA and EPA production. Longer fatty acids that have more double bonds than AA or EPA are less frequently produced due to a deficiency in delta 4 desaturating ability. The process of retroconversion (chain shortening) is less extensively studied, but evidence from a variety of cells suggests that this type of metabolic conversion is normally active. The example of MCF-7 (human breast cancer cell line) and MCF-10A cells (human noncancerous breast cell line) is discussed in order to emphasize the diversity in EFA processing ability of cultured cells. Under identical culture conditions, MCF-10A cells perform extensive desaturations, elongations, and retroconversions, whereas MCF-7 cells can only elongate and retroconvert exogenous EFAs. Given the great diversity in the ability of cultured cells to process EFAs, no conclusions can be drawn regarding the mechanisms responsible for the effects of exogenous EFAs on a particular cell until that cell's EFA processing patterns have been evaluated.