Department of Pharmacy, Shiga University of Medical Science Hospital, Otsu, Shiga, 520-2192, Japan.
Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan.
Sci Rep. 2021 Feb 1;11(1):2731. doi: 10.1038/s41598-021-81733-3.
The human hepatoblastoma cell line, HepG2, has been used for investigating a wide variety of physiological and pathophysiological processes. However, less information is available about the phospholipid metabolism in HepG2 cells. In the present report, to clarify the relationship between cell growth and phospholipid metabolism in HepG2 cells, we examined the phospholipid class compositions of the cells and their intracellular organelles by using enzymatic fluorometric methods. In HepG2 cells, the ratios of all phospholipid classes, but not the ratio of cholesterol, markedly changed with cell growth. Of note, depending on cell growth, the phosphatidic acid (PA) ratio increased and phosphatidylcholine (PC) ratio decreased in the nuclear membranes, the sphingomyelin (SM) ratio increased in the microsomal membranes, and the phosphatidylethanolamine (PE) ratio increased and the phosphatidylserine (PS) ratio decreased in the mitochondrial membranes. Moreover, the mRNA expression levels of enzymes related to PC, PE, PS, PA, SM and cardiolipin syntheses changed during cell growth. We suggest that the phospholipid class compositions of organellar membranes are tightly regulated by cell growth. These findings provide a basis for future investigations of cancer cell growth and lipid metabolism.
人肝癌细胞系 HepG2 已被用于研究广泛的生理和病理生理过程。然而，关于 HepG2 细胞中的磷脂代谢的信息较少。在本报告中，为了阐明 HepG2 细胞中细胞生长与磷脂代谢之间的关系，我们使用酶荧光法检测了细胞及其细胞内细胞器的磷脂类组成。在 HepG2 细胞中，所有磷脂类的比例，但胆固醇的比例，随着细胞生长而显著变化。值得注意的是，根据细胞生长，核膜中的磷脂酸（PA）比例增加，磷脂酰胆碱（PC）比例降低，微粒体膜中的神经鞘磷脂（SM）比例增加，线粒体膜中的磷脂酰乙醇胺（PE）比例增加，磷脂酰丝氨酸（PS）比例降低。此外，与 PC、PE、PS、PA、SM 和心磷脂合成相关的酶的 mRNA 表达水平在细胞生长过程中发生变化。我们认为，细胞器膜的磷脂类组成受到细胞生长的严格调控。这些发现为未来研究癌细胞生长和脂质代谢提供了基础。
