LIPID TURNOVER & GROWTH OF NORMAL & TUMOR MAMMARY CELLS

这个应用程序的长期目标是阐明 脂类参与正常儿童生长调节的机制 和肿瘤乳腺上皮细胞(MEC)。孤立法线 MEC包埋在胶原胶中，在 对生长因子、促乳房激素和18：2，(n- 6)。分析18：2对正常微血管内皮细胞增殖的影响 发现二十烷类化合物，PGE2和HETES，可以协同作用 在MEC存在的情况下保持MEC的增殖 基础培养上清液中加入胰岛素的EGF。其他代理商，如TPA， 锂、cAMP和二(18：2)-磷脂酸可支持生长 MEC在无生长因子或无生长因子的基础培养中的表达 生乳房的激素。这些观察表明 脂质反应途径参与微血管内皮细胞的增殖。 该途径的成分可能包括以下代谢产物 磷脂周转、二十烷类化合物、蛋白激酶A和蛋白质 激酶-C。与正常的MEC不同，肿瘤细胞是异质性的 因此，它们对18：2的增殖反应不同。它 观察到，虽然一些肿瘤细胞依赖于18：2 为了实现最大限度的增长，其他公司则不是这样。关于以下方面的报道 喂食抑制啮齿动物乳腺肿瘤生长(n-3) PUFA可解释为18：2和20：4的直接干预 饲料中(n-3)多不饱和脂肪酸的代谢。为了揭开 可能解释这一作用的脂质反应途径的细节 关于(n-6)和(n-3)多不饱和脂肪酸，建议进行以下研究 以确定：(A)是否所有的激素和非激素生长 MEC的启动子需要(n-6)PUFA的代谢物 持续的细胞增殖，(B)磷脂的产物 周转和PL周期中间体参与了 增殖信号的产生，(C)是否有任何差异 二十烷类化合物、环磷酸腺苷和环磷酸腺苷的产生和反应 CGMP，表征了18：2依赖的 和--独立的乳腺肿瘤，(D)是否(n-3)PUFA 抑制对正常和肿瘤MEC增殖的调控作用 从20：4(n-6)开始生产二十烷类化合物，最后，(E)是否 激酶A和激酶C与推测的脂质- 细胞增殖的反应途径。世界上最重要的一部分 将在无血清培养系统中开展工作，使用 正常小鼠和肿瘤小鼠的MEC。对增长的影响将是 在没有脂质类似物或酶的情况下进行检查 抑制剂。将通过暴露细胞来研究脂代谢， 预标有前体的，到激动剂。脂类(包括 二十碳酸类)和环核苷酸将通过 层析和/或放射免疫分析。无细胞蛋白激酶活性， 80 kDa蛋白的磷酸化及标记PDBu、In的结合 对激动剂的反应将被确定。努力渡过难关 项目，我们希望能够了解血脂是如何调节的 正常和肿瘤乳腺组织的生长可能 为未来的预防和治疗措施提供方法。

The long-term objective of this application is to elucidate the mechanism of lipid involvement in growth regulation of normal and tumor mammary epithelial cells (MEC). Isolated normal MEC, embedded in collagen gel, proliferate and differentiate in response to growth factors, mammogenic hormones and 18:2, (n- 6). Analyzing the effects of 18:2 on normal MEC proliferation, it was found that the eicosanoids, PGE2 and HETEs, can synergize with each other in sustaining proliferation of MEC in the presence of EGF in basal medium with insulin. Other agents like TPA, lithium, cAMP and di(18:2)-phosphatidic acid can support growth of MEC in basal medium in the absence of growth factors or mammogenic hormones. These observations indicate the involvement of a lipid-responsive pathway in MEC proliferation. The components of this pathway may include metabolites of phospholipid turnover, eicosanoids, protein kinase A and protein kinase-C. Unlike normal MEC, tumor cells are heterogeneous and, consequently, vary in their proliferative response to 18:2. It was observed that, while some tumor cells are dependent on 18:2 for maximum growth, others are not. The reports concerning inhibition of mammary tumor growth in rodents by feeding (n-3) PUFA may be explained as direct intervention of 18:2 and 20:4 metabolism by dietary (n-3) PUFA. In order to uncover the details of a lipid-responsive pathway which may explain the role of (n-6) and (n-3) PUFA, the following studies are being proposed to determine: (a) whether all hormonal and nonhormonal growth promoters of MEC require metabolites of (n-6) PUFA for sustained cell proliferation, (b) whether products of phospholipid turnover and Pl-cycle intermediates are involved in the generation of proliferative signals, (c) whether any difference in the production of and responsiveness to eicosanoids, cAMP and cGMP, characterize the difference between the 18:2-dependent and -independent mammary tumors, (d) whether (n-3) PUFA regulate proliferation of normal and neoplastic MEC by inhibiting eicosanoid production from 20:4 (n-6) and finally, (e) whether kinase A and kinase-C are associated with the putative lipid- responsive pathway for cell proliferation. A major part of the work will be carried out in serum-free culture system using normal and neoplastic mouse MEC. The effects on growth will be examined in the presence of absence of lipid analogues or enzyme inhibitors. Lipid turnover will be studied by exposing cells, prelabelled with precursors, to agonists. Lipids (including eicosanoids) and cyclic nucleotides will be analyzed by chromatography and/or RIA. cell-free protein kinase activities, phosphorylation of 80 kDa protein and binding of labeled PDBu, in response to agonists, will be determined. Working through this project, we hope to be able to understand how lipids regulate growth of normal and tumor mammary tissues which might provide ways for future preventive and therapeutic measures.