【摘要】 目的　研究人白细胞介素 4(IL 4)对肝母细胞瘤细胞系 (HepG2 )分化诱导作用及诱导分化过程中端粒酶活性的变化及可能机制。方法　用锥虫蓝拒染活细胞染色法、流式细胞仪细胞周期分析、瑞氏染色形态学检测、放射免疫测定、原位杂交等方法检测IL 4处理前、后细胞的增殖、形态、甲胎球蛋白合成及原癌基因c fos、c myc表达情况。聚合酶链反应结合酶联免疫吸附实验 (PCR ELISA)半定量检测瘤细胞端粒酶活性。用无血清培养使细胞周期同步于静止期 (G0 G1 )的方法 ,探讨端粒酶在瘤细胞被诱导分化过程中的活性变化与细胞周期时相的关系。结果　IL 4处理后HepG2 细胞生长速度减慢 (n =10 ,F =16 .7,P <0 .0 5 ) ,c fos和c myc基因表达积分从 (2 79± 2 1) %、(2 10±39) %降至 (38± 8) %及 (16± 5 ) % (n =10 ,t值分别为 13 6、8 4,P均 <0 .0 1)。G0 G1 细胞由 (4 5 .4± 2 .7) %增至 (5 7.8± 3 .3) % (n =10 ,t=4.2 ,P <0 .0 5 ) ;细胞形态趋向正常肝细胞形态转化 ;2 4h每 10 6个肿瘤细胞甲胎球蛋白分泌量从 (15 .6± 0 .7)ng降至 (4 .5± 1.2 )ng(n =10 ,t=9.8,P <0 .0 5 )。同时还发现IL 4处理后 48h端粒酶活性即见明显下降 ,A值 (代表端粒酶活性 )即由处理前的 1.2降至0 .7(t=8.4,P <0 .0 1) ,72hA值降至更多还原

【Abstract】 Objective To investigate the effects and the possible mechanisms of human interleukin 4 (IL 4) on the differentiation and the activity of telomerase in hepatoblastoma cell line ( HepG 2 ) cells. Methods Trypan blue exclusion dye, Wright dye, analysis of cell cycle by flow cytometry, radioimmunoassay, and in situ hybridization were used to determine the proliferation, the change of morphology, the cell cycle, the synthesis of alpha fetoprotein (AFP) and the expression of protooncogenes, such as c fos, and c myc. Polymerase chain reaction enzyme linked immunosorbent assay (PCR ELISA) was used to detect the activity of telomerase in tumor cells. Cell culture in serum free medium was employed to evaluate the relation of telomerase activity in differentiated tumor cells and the change of cell cycle. Results The treatment of tumor cells with IL 4 slowed down the cells growth rate ( n =10, F =16.7, P <0.05) and arrested the cell cycle at G 0/G 1 stage. The population of IL 4 treated tumor cells was (57.8±3.5)% while (45.4±2.7)% in wild HepG2 cells. After treatment with IL 4, the shape of HepG 2 cells became relatively mature and the synthesis of AFP decreased from (15.6±0.7) ng/(10 6 cells·24h) to (4.5±1.2)ng/(10 6 cells·24h). The expressions of c fos and c myc reduced ( n =10; t =13.6, 8.4; P <0.01). At the same time, the activity of telomerase was decreased just after 48 hours treatment with IL 4, the “ A ” value, which stands for the activity of telomerase, decreased from 1.2 to 0.7. The changes of the activity of telomerase were independent of the cell cycle. The 12 0 tetradecanoyl 13 acetate (TPA), which is an activator of protein kinase (PKC), could reverse the differentiation and the effect of down regulating telomerase activity by IL 4. Conclusion Treatment with IL 4 could induce the differentiation of hepatoblastoma cells and down regulate the activities of telomarase. These effects were likely to relate to the inhibition of PKC activity.更多还原