Department of General Surgery, The Second Affiliated Hospital of Harbin Medical University, Baojian Road, Harbin, 150086, China.
Biol Res. 2019 Jun 13;52(1):32. doi: 10.1186/s40659-019-0239-2.
Long non-coding RNA H19 (H19) plays an important role by regulating protein expression in different tissues and organs of the body. However, whether H19 induces hypoxia/reoxygenation (h/R) injury via increase of autophagy in the hepatoma carcinoma cells is unknown.
H19 was expressed in the hepatoma carcinoma cells (Hep G2 and HCCLM3 cells) and its expression was most in 8 h/24R. The knockdown of H19 and 3-MA (an autophagy inhibitor) protected against h/R-induced apoptosis, cell damage, the expression of cleaved caspase-3 and cleaved caspase-9, the release of cytochrome c (Cyt c). The knockdown of H19 and 3-MA also decreased the autophagic vesicles (AVs) and the expression of Beclin-1 and the ration of LC3-II/LC3-I, and increased cell viability, the expression of Bcl-2 and P62 and the phosphorylation of PI3K, Akt and mTOR. In addition, chloroquine (CQ, an inhibitor of autophagy flux) markedly decreased formation of autophagy flux (the ration of LC3-II/LC3-I). The results of the knockdown of H19 group were similar to those of the 3-MA (or CQ) group. Rapamycin (a mTOR inhibitor, an autophagy activator) further down-regulated h/R-induced decrease of the phosphorylated PI3K, Akt and mTOR. The knockdown of H19 cancelled the effect of rapamycin. The overexpression of H19 further expanded h/R-induced increase of the ration of LC3-II/LC3-I and decrease of the phosphorylated PI3K, Akt and mTOR.
Our results suggest that the long non-coding RNA H19 induces h/R injury by up-regulation of autophagy via activation of PI3K-Akt-mTOR pathway in the hepatoma carcinoma cells.
长链非编码 RNA H19（H19）通过调节体内不同组织和器官的蛋白质表达发挥重要作用。然而，H19 是否通过增加肝癌细胞中的自噬来诱导缺氧/复氧（h/R）损伤尚不清楚。
H19 在肝癌细胞（Hep G2 和 HCCLM3 细胞）中表达，其表达在 8 h/24R 时最高。H19 的敲低和 3-MA（自噬抑制剂）可防止 h/R 诱导的细胞凋亡、细胞损伤、cleaved caspase-3 和 cleaved caspase-9 的表达、细胞色素 c（Cyt c）的释放。H19 的敲低和 3-MA 还降低了自噬小体（AVs）和 Beclin-1 的表达以及 LC3-II/LC3-I 的比值，并增加了细胞活力、Bcl-2 和 P62 的表达以及 PI3K、Akt 和 mTOR 的磷酸化。此外，氯喹（CQ，自噬流的抑制剂）显著减少了自噬流的形成（LC3-II/LC3-I 的比值）。H19 敲低组的结果与 3-MA（或 CQ）组相似。雷帕霉素（mTOR 抑制剂，自噬激活剂）进一步下调了 h/R 诱导的磷酸化 PI3K、Akt 和 mTOR 的降低。H19 的敲低取消了雷帕霉素的作用。H19 的过表达进一步扩大了 h/R 诱导的 LC3-II/LC3-I 比值增加和磷酸化 PI3K、Akt 和 mTOR 降低。
我们的结果表明，长链非编码 RNA H19 通过激活 PI3K-Akt-mTOR 通路增加自噬，从而诱导肝癌细胞的 h/R 损伤。
