层粘连蛋白诱导体外生长的肝癌细胞表达细胞角蛋白19

Cytokeratin 19 expression induced by laminin in cultured hepatocellular carcinoma cells

目的 观察层粘连蛋白 (LN)对细胞角蛋白 (CK) 19异常表达的诱导作用 ,进一步探讨肝实质细胞额外表达CK19的分子机制。方法 对选择的 3株肝细胞癌 (HCC)细胞系的CK 19和LN的表达进行免疫酶细胞化学、免疫印迹和激光共聚焦显微镜观察 ;用含有LN的培养液进行CK19表达诱导 ,应用LN的多克隆抗体阻断这一效应。结果 3株细胞系中有 1株产生内源性LN ,并且表达CK19,其余 2株这两种分子的表达均为阴性。当接种于含有外源性LN的培养液中生长时 ,原来CK阴性的 2株HCC细胞系均出现CK19的表达 ,其水平与LN剂量相关。LN的多克隆抗体可完全阻断外源性及内源性LN对CK19表达的诱导作用。结论 LN确实能够诱导体外生长的HCC细胞表达CK19。

Objective To study the molecular mechanism of the abnormal expression of cytokeratin (CK) 19 in liver parenchymal cells and its possible link to laminin (LN). Methods Three selected hepatocellular carcinoma (HCC) cell lines were examined for CK19 and LN by immunocytochemistry, Western blot, and confocal laser scanning microscopy. Moreover, the induction tests were carried out by culturing the CK19 negative HCC cells in a medium containing purified LN, the specificity of the effect was determined by a blocking test of polyclonal anti LN. Results Both CK19 and LN were found to be coexpressed in one cell line and negative in the other two cell lines, the coexpression was further verified by confocal laser scanning microscopy. With addition of LN to the culture medium, two HCC cell lines formerly negative for CK19, began to express CK19, the reaction was dose dependent. Addition of polyclonal anti LN to the medium could completely block the induction effect. Conclusions LN can induce expression of CK19 in HCC cells in vitro, this study provides direct evidence for our hypothesis that CK19 expression in liver parenchyma is associated with abnormal LN deposition.