Department of Experimental Hematology, Beijing Institute of Radiation Medicine, 27 Taiping Road, Beijing 100850, China.
World J Gastroenterol. 2010 Jan 14;16(2):193-200. doi: 10.3748/wjg.v16.i2.193.
To investigate the role of hepatopoietin Cn (HPPCn) in apoptosis of hepatocellular carcinoma (HCC) cells and its mechanism.
Two human HCC cell lines, SMMC7721 and HepG2, were used in this study. Immunostaining, Western blotting and enzyme linked immunosorbent assay were conducted to identify the expression of HPPCn and the existence of an autocrine loop of HPPCn/HPPCn receptor in SMMC7721 and HepG2. Apoptotic cells were detected using fluorescein isothiocyanate (FITC)-conjugated Annexin V and propidium iodide.
The HPPCn was highly expressed in human HCC cells and secreted into culture medium (CM). FITC-labeled recombinant human protein (rhHPPCn) could specifically bind to its receptor on HepaG2 cells. Treatment with 400 ng/mL rhHPPCn dramatically increased the viability of HCC-derived cells from 48.1% and 36.9% to 85.6% and 88.4%, respectively (P < 0.05). HPPCn silenced by small-interfering RNA reduced the expression and secretion of HPPCn and increased the apoptosis induced by trichostatin A. Additionally, HPPCn could up-regulate the expression of myeloid cell leukemia-1 (Mcl-1) in HCC cells via mitogen-activated protein kinase (MAPK) and sphingosine kinase-1.
HPPCn is a novel hepatic growth factor that can be secreted to CM and suppresses apoptosis of HCC cells by up-regulating Mcl-1 expression.
研究肝实质细胞生成素 Cn（HPPCn）在肝癌细胞凋亡中的作用及其机制。
本研究采用了两种人肝癌细胞系，SMMC7721 和 HepG2。通过免疫染色、Western blot 和酶联免疫吸附试验鉴定 HPPCn 在 SMMC7721 和 HepG2 中的表达以及 HPPCn/HPPCn 受体的自分泌环的存在。使用异硫氰酸荧光素（FITC）标记的 Annexin V 和碘化丙啶检测凋亡细胞。
HPPCn 在人肝癌细胞中高度表达并分泌到培养基（CM）中。FITC 标记的重组人蛋白（rhHPPCn）可以特异性结合 HepaG2 细胞上的受体。用 400ng/ml rhHPPCn 处理后，肝癌衍生细胞的活力分别从 48.1%和 36.9%显著增加至 85.6%和 88.4%（P<0.05）。小干扰 RNA 沉默 HPPCn 降低了 HPPCn 的表达和分泌，并增加了 Trichostatin A 诱导的凋亡。此外，HPPCn 可以通过丝裂原活化蛋白激酶（MAPK）和鞘氨醇激酶-1 上调 HCC 细胞中髓样细胞白血病-1（Mcl-1）的表达。
HPPCn 是一种新型的肝生长因子，可分泌到 CM 中，并通过上调 Mcl-1 表达抑制肝癌细胞凋亡。
