Bratt T
M&E Biotech A/S, Kogle Alle 6, DK-2970 Horsholm, Denmark.
Biochim Biophys Acta. 2000 Oct 18;1482(1-2):318-26. doi: 10.1016/s0167-4838(00)00154-0.
Lipocalins are mainly extracellular carriers of lipophilic molecules, though exceptions with properties like prostaglandin synthesis and protease inhibition are observed for specific lipocalins. The interest concerning lipocalins in cancer has so far been focussed to the variations in concentration and the modification of lipocalin expression in distinct cancer forms. In addition, lipocalins have been assigned a role in cell regulation. The influence of the extracellular lipocalins on intracellular cell regulation events is not fully understood, but several of the lipocalin ligands are also well-known agents in cell differentiation and proliferation. Lipophilic ligands can, after lipocalin-mediated transport to the cell surface, penetrate the cell membrane and interact with proteins in the cytosol and/or the nucleus. The signaling routes of the lipocalin ligands, retinoids and fatty acids are presented and discussed. Tumor growth in tissue is restricted by extracellular protease/protease inhibitor interactions. Several lipocalins also have protease inhibitory properties and possess the ability to interact with tumor specific proteases, revealing another pathway for lipocalins to interact with cancer cells.
脂质运载蛋白主要是亲脂性分子的细胞外载体，不过某些特定的脂质运载蛋白具有如前列腺素合成和蛋白酶抑制等特性，属于例外情况。目前，癌症领域对脂质运载蛋白的关注主要集中在不同癌症类型中其浓度的变化以及表达的修饰上。此外，脂质运载蛋白在细胞调节中也发挥着作用。细胞外脂质运载蛋白对细胞内调节事件的影响尚未完全明确，但一些脂质运载蛋白配体也是细胞分化和增殖方面的知名因子。亲脂性配体在脂质运载蛋白介导下转运至细胞表面后，可穿透细胞膜并与细胞质和/或细胞核中的蛋白质相互作用。本文将介绍并讨论脂质运载蛋白配体、视黄酸和脂肪酸的信号传导途径。组织中的肿瘤生长受到细胞外蛋白酶/蛋白酶抑制剂相互作用的限制。一些脂质运载蛋白也具有蛋白酶抑制特性，能够与肿瘤特异性蛋白酶相互作用，这揭示了脂质运载蛋白与癌细胞相互作用的另一条途径。
