Grammatikos S I, Subbaiah P V, Victor T A, Miller W M
Department of Chemical Engineering, Northwestern University, Evanston, Illinois 60208-3120.
Cytotechnology. 1994;15(1-3):31-50. doi: 10.1007/BF00762377.
Fatty acids (FAs) have long been recognized for their nutritional value in the absence of glucose, and as necessary components of cell membranes. However, FAs have other effects on cells that may be less familiar. Polyunsaturated FAs of dietary origin (n-6 and n-3) cannot be synthesized by mammals, and are termed 'essential' because they are required for the optimal biologic function of specialized cells and tissues. However, they do not appear to be necessary for normal growth and metabolism of a variety of cells in culture. The essential fatty acids (EFAs) have received increased attention in recent years due to their presumed involvement in cardiovascular disorders and in cancers of the breast, pancreas, colon and prostate. Many in vitro systems have emerged which either examine the role of EFAs in human disease directly, or utilize EFAs to mimic the in vivo cellular environment. The effects of EFAs on cells are both direct and indirect. As components of membrane phospholipids, and due to their varying structural and physical properties, EFAs can alter membrane fluidity, at least in the local environment, and affect any process that is mediated via the membrane. EFAs containing 20 carbons and at least three double bonds can be enzymatically converted to eicosanoid hormones, which play important roles in a variety of physiological and pathological processes. Alternatively, EFAs released into cells from phospholipids can act as second messengers that activate protein kinase C. Furthermore, susceptibility to oxidative damage increases with the degree of unsaturation, a complication that merits consideration because lipid peroxidation can lead to a variety of substances with toxic and mutagenic properties. The effects of EFAs on cultured cells are illustrated using the responses of normal and tumor human mammary epithelial cells. A thorough evaluation of EFA effects on commercially important cells could be used to advantage in the biotechnology industry by identifying EFA supplements that lead to improved cell growth and/or productivity.
脂肪酸（FAs）长期以来因其在缺乏葡萄糖时的营养价值以及作为细胞膜的必要成分而被人们所认识。然而，脂肪酸对细胞还有其他一些可能不太为人熟悉的作用。膳食来源的多不饱和脂肪酸（n - 6和n - 3）不能由哺乳动物合成，因其是特殊细胞和组织实现最佳生物学功能所必需的，故而被称为“必需脂肪酸”。然而，它们对于培养的多种细胞的正常生长和代谢似乎并非必需。近年来，必需脂肪酸（EFAs）因其被推测与心血管疾病以及乳腺癌、胰腺癌、结肠癌和前列腺癌有关而受到越来越多的关注。出现了许多体外系统，它们要么直接研究必需脂肪酸在人类疾病中的作用，要么利用必需脂肪酸来模拟体内细胞环境。必需脂肪酸对细胞的影响既有直接的，也有间接的。作为膜磷脂的成分，并且由于其不同的结构和物理性质，必需脂肪酸能够改变膜流动性，至少在局部环境中如此，并影响任何通过膜介导的过程。含有20个碳原子且至少有三个双键的必需脂肪酸可被酶促转化为类二十烷酸激素，这些激素在多种生理和病理过程中发挥重要作用。另外，从磷脂释放到细胞中的必需脂肪酸可作为激活蛋白激酶C的第二信使。此外，氧化损伤的易感性会随着不饱和程度的增加而升高，这一复杂情况值得考虑，因为脂质过氧化会导致产生多种具有毒性和致突变性的物质。通过正常和肿瘤人类乳腺上皮细胞的反应来说明必需脂肪酸对培养细胞的影响。对必需脂肪酸对具有商业重要性的细胞的影响进行全面评估，通过确定能促进细胞生长和/或提高生产力的必需脂肪酸补充剂，可在生物技术产业中发挥优势。
