Laboratory animal center, Dalian medical University, Dalian, Liaoning, 116044, China.
Cancer Med. 2017 Oct;6(10):2370-2384. doi: 10.1002/cam4.1177. Epub 2017 Sep 21.
Activation of the Ras/MAPK pathway is prevalently involved in the occurrence and development of hepatocellular carcinoma (HCC). However, its effects on the deregulated cellular metabolic processes involved in HCC in vivo remain unknown. In this study, a mouse model of HCC induced by hepatocyte-specific expression of the Hras12V oncogene was investigated using an integrative analysis of metabolomics and transcriptomics data. Consistent with the phenotype of abundant lipid droplets in HCC, the lipid biosynthesis in HCC was significantly enhanced by (1) a sufficient supply of acetyl-CoA from enhanced glycolysis and citrate shuttle activity; (2) a sufficient supply of NADPH from enhanced pentose phosphate pathway (PPP) activity; (3) upregulation of key enzymes associated with lipid biosynthesis; and (4) downregulation of key enzymes associated with bile acid biosynthesis. In addition, glutathione (GSH) was significantly elevated, which may result from a sufficient supply of 5-oxoproline and L-glutamate as well as an enhanced reduction in the process of GSSG being turned into GSH by NADPH. The high level of GSH along with elevated Bcl2 and Ucp2 expression may contribute to a normal level of reactive oxygen species (ROS) in HCC. In conclusion, our results suggest that the lipid metabolism, glycolysis, PPP, tricarboxylic acid (TCA) cycle, citrate shuttle activity, bile acid synthesis, and redox homeostasis in the HCC induced by ras oncogene are significantly perturbed, and these altered metabolic processes may play crucial roles in the carcinogenesis, development, and pathological characteristics of HCC.
Ras/MAPK 通路的激活普遍参与了肝细胞癌(HCC)的发生和发展。然而,其对体内 HCC 中涉及的细胞代谢过程失调的影响尚不清楚。在这项研究中,我们通过代谢组学和转录组学数据的综合分析,研究了由肝细胞特异性表达 Hras12V 癌基因诱导的 HCC 小鼠模型。与 HCC 中大量脂滴的表型一致,HCC 中的脂质生物合成通过以下方式显著增强:(1)增强的糖酵解和柠檬酸穿梭活性提供足够的乙酰辅酶 A;(2)增强的戊糖磷酸途径(PPP)活性提供足够的 NADPH;(3)上调与脂质生物合成相关的关键酶;(4)下调与胆汁酸生物合成相关的关键酶。此外,谷胱甘肽(GSH)显著升高,这可能是由于 5-氧脯氨酸和 L-谷氨酸的充足供应以及 GSSG 转化为 GSH 的过程中 NADPH 的增强还原所致。高水平的 GSH 伴随着 Bcl2 和 Ucp2 表达的升高,可能有助于 HCC 中活性氧(ROS)水平正常。总之,我们的结果表明,ras 癌基因诱导的 HCC 中的脂质代谢、糖酵解、PPP、三羧酸(TCA)循环、柠檬酸穿梭活性、胆汁酸合成和氧化还原稳态受到显著干扰,这些改变的代谢过程可能在 HCC 的致癌、发展和病理特征中发挥关键作用。