Mezzasoma L, Biondi R, Benedetti C, Floridi C, Ciurnelli R, Falcinelli F, Onorato M, Scaringi L, Marconi P, Rossi R
Department of Clinical Medicine, Pathology and Pharmacology, University of Perugia, Italy.
J Biol Regul Homeost Agents. 1993 Oct-Dec;7(4):126-32.
This study shows that the human hepatoblastoma cell line Hep G2 constitutively expressed a high level of Leukemia Inhibitory Factor (LIF) mRNA in the characteristic major 3.8 and minor 1.8 Kb forms. DNA analysis of the LIF gene from Hep G2 revealed no rearrangements. Production and secretion of significant concentrations of LIF were demonstrated by enzyme-linked immunoabsorbent assay (ELISA) in culture supernatants of Hep G2 cells. The highest LIF concentration in culture was found at 48-h (250 pg/ml). LIF produced by Hep G2 cells was biologically active since cell-free culture supernatants were able to induce in vitro differentiation of the M1 murine myeloid leukemia cell line. On the contrary, no LIF mRNA expression was detected in normal liver cells by PCR analysis. Our results suggest that LIF acts on normal parenchymal hepatocytes through a paracrine mechanism and on Hep G2 cells by an autocrine action. Furthermore they indicate that the Hep G2 cell line could be an useful model for studying the LIF autocrine mechanism in hepatomas.
本研究表明，人肝癌细胞系Hep G2以特征性的主要3.8 kb和次要1.8 kb形式组成性地高水平表达白血病抑制因子（LIF）mRNA。对Hep G2细胞的LIF基因进行DNA分析，未发现重排。通过酶联免疫吸附测定（ELISA）在Hep G2细胞的培养上清液中证实了有显著浓度的LIF产生和分泌。培养物中最高的LIF浓度在48小时时被发现（250 pg/ml）。Hep G2细胞产生的LIF具有生物活性，因为无细胞培养上清液能够诱导M1小鼠髓系白血病细胞系的体外分化。相反，通过PCR分析在正常肝细胞中未检测到LIF mRNA表达。我们的结果表明，LIF通过旁分泌机制作用于正常实质肝细胞，并通过自分泌作用作用于Hep G2细胞。此外，它们表明Hep G2细胞系可能是研究肝癌中LIF自分泌机制的有用模型。
