Guštin Ema, Jarc Eva, Kump Ana, Petan Toni
Acta Chim Slov. 2017 Sep;64(3):549-554. doi: 10.17344/acsi.2016.2908.
Cytosolic lipid droplets (LDs) store excess fatty acids (FAs) in the form of neutral lipids and prevent starvation-induced cancer cell death. Here we studied the ability of mono- and polyunsaturated FAs to affect LD formation and survival in HeLa cervical cancer cells. We found that the LD content in HeLa cells increases with cell density, but it decreases in MDA-MB-231 breast cancer cells. Exogenously-added unsaturated FAs, including oleic (OA), linoleic (LA), arachidonic (AA), eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) displayed a similar ability to alter LD formation in HeLa cells. There was a dual, concentration-dependent effect on neutral lipid accumulation: low micromolar concentrations of LA, AA and DHA reduced, while all FAs induced LD formation at higher concentrations. In serum starved He-La cells, OA stimulated LD formation, but, contrary to expectations, it promoted cell death. Our results reveal a link between cell population density and LD formation in HeLa cells and show that unsaturated FAs may both suppress or stimulate LD formation. This dynamic regulation of LD content must be accounted for when studying the effects of lipids and lipid metabolism-targeting drugs on LD metabolism in HeLa cells.
胞质脂滴（LDs）以中性脂质的形式储存过量脂肪酸（FAs），并防止饥饿诱导的癌细胞死亡。在此，我们研究了单不饱和脂肪酸和多不饱和脂肪酸影响HeLa宫颈癌细胞中脂滴形成和存活的能力。我们发现，HeLa细胞中的脂滴含量随细胞密度增加而增加，但在MDA-MB-231乳腺癌细胞中则减少。外源添加的不饱和脂肪酸，包括油酸（OA）、亚油酸（LA）、花生四烯酸（AA）、二十碳五烯酸（EPA）和二十二碳六烯酸（DHA），在改变HeLa细胞中脂滴形成方面表现出相似的能力。对中性脂质积累存在双重的浓度依赖性效应：低微摩尔浓度的LA、AA和DHA会减少脂滴形成，而所有脂肪酸在较高浓度时均会诱导脂滴形成。在血清饥饿的HeLa细胞中，OA刺激脂滴形成，但与预期相反，它促进细胞死亡。我们的结果揭示了HeLa细胞中细胞群体密度与脂滴形成之间的联系，并表明不饱和脂肪酸可能既抑制也刺激脂滴形成。在研究脂质和靶向脂质代谢的药物对HeLa细胞中脂滴代谢的影响时，必须考虑脂滴含量的这种动态调节。
