Jang Yumi, Park Na-Young, Rostgaard-Hansen Agnetha Linn, Huang Jianjie, Jiang Qing
Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA.
Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA.
Free Radic Biol Med. 2016 Jun;95:190-9. doi: 10.1016/j.freeradbiomed.2016.03.018. Epub 2016 Mar 23.
Vitamin E forms are substantially metabolized to various carboxychromanols including 13'-carboxychromanols (13'-COOHs) that are found at high levels in feces. However, there is limited knowledge about functions of these metabolites. Here we studied δT-13'-COOH and δTE-13'-COOH, which are metabolites of δ-tocopherol and δ-tocotrienol, respectively. δTE-13'-COOH is also a natural constituent of a traditional medicine Garcinia Kola. Both 13'-COOHs are much stronger than tocopherols in inhibition of pro-inflammatory and cancer promoting cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX), and in induction of apoptosis and autophagy in colon cancer cells. The anticancer effects by 13'-COOHs appeared to be partially independent of inhibition of COX-2/5-LOX. Using liquid chromatography tandem mass spectrometry, we found that 13'-COOHs increased intracellular dihydrosphingosine and dihydroceramides after short-time incubation in HCT-116 cells, and enhanced ceramides while decreased sphingomyelins during prolonged treatment. Modulation of sphingolipids by 13'-COOHs was observed prior to or coinciding with biochemical manifestation of cell death. Pharmaceutically blocking the increase of these sphingolipids partially counteracted 13'-COOH-induced cell death. Further, 13'-COOH inhibited dihydroceramide desaturase without affecting the protein expression. In agreement with these mechanistic findings, δTE-13'-COOH significantly suppressed the growth and multiplicity of colon tumor in mice. Our study demonstrates that 13'-COOHs have anti-inflammatory and anticancer activities, may contribute to in vivo anticancer effect of vitamin E forms and are promising novel cancer prevention agents.
维生素E的各种形式会大量代谢为多种羧基色满醇,包括在粪便中含量很高的13'-羧基色满醇(13'-COOHs)。然而,关于这些代谢产物的功能,人们了解有限。在此,我们研究了δT-13'-COOH和δTE-13'-COOH,它们分别是δ-生育酚和δ-生育三烯酚的代谢产物。δTE-13'-COOH也是传统药物可乐果的一种天然成分。两种13'-COOHs在抑制促炎和促癌的环氧化酶-2(COX-2)和5-脂氧合酶(5-LOX)方面,以及在诱导结肠癌细胞凋亡和自噬方面,都比生育酚要强得多。13'-COOHs的抗癌作用似乎部分独立于对COX-2/5-LOX的抑制。使用液相色谱串联质谱法,我们发现13'-COOHs在HCT-116细胞中短期孵育后会增加细胞内二氢鞘氨醇和二氢神经酰胺,而在长时间处理过程中会增强神经酰胺同时减少鞘磷脂。在细胞死亡的生化表现之前或同时观察到13'-COOHs对鞘脂的调节作用。通过药物阻断这些鞘脂的增加部分抵消了13'-COOH诱导的细胞死亡。此外,13'-COOH抑制二氢神经酰胺去饱和酶,但不影响其蛋白表达。与这些机制研究结果一致,δTE-13'-COOH显著抑制了小鼠结肠肿瘤的生长和增殖。我们的研究表明,13'-COOHs具有抗炎和抗癌活性,可能有助于维生素E各种形式的体内抗癌作用,并且是有前景的新型癌症预防剂。