活化血管内皮生长因子受体1诱导肝癌细胞株MHCC97-H细胞上皮-间叶表型转化的分子机制

Molecular mechanism of epithelial-mesenchymal transition induced by activated vascular endothelial growth factor receptor-1 in cell line MHCC97-H

目的探讨活化血管内皮生长因子受体1（VEGFR-1）诱导肝癌细胞株MHCC97-H细胞上皮-间叶表型转化（EMT）的分子机制。方法将MHCC97-H细胞分为对照组（1％胎牛血清的DMEM培养）、PP2组（10μmol／LPP2培养）、PBS组（10μmol／LPBS培养）、VEGF—B组（50μg/L的VEGF—B培养）、PP2＋VEGF—B组（10μmol／LPP2和50μ/L的VEGF—B培养）、PBS＋VEGF—B组（10μmol／LPBS和50μg/L VEGF-B培养）。Western blot法检测各组上皮标志物E-钙黏蛋白、α-连环蛋白和间叶标志物波形蛋白、N-钙黏蛋白的表达水平；细胞免疫荧光检测上述蛋白的表达部位；细胞侵袭和迁移试验检测各组MHCC97-H细胞的侵袭和运动能力。组间比较采用t检验。结果对照组、PP2组、PBS组、VEGF—B组、PP2＋VEGF-B组、PBS＋VEGF—B组的MHCC97-H细胞上皮标志物E-钙黏蛋白的表达分别为3．23±0．76、4．18±0．32、2．83±0．65、2．06±0．15、6．12±0．08、1．36±0．54；α-连环蛋白的表达分别为3．01±0．25、3．29±0．11、3．03±0．27、2．84±0．76、5．45±0．37、1．26±0．45；波形蛋白的表达分别为3．01±0．22、4．85±0．36、1．37±0．24、5．79±0．38、3．36±0．42、4．05±0．17；N-钙黏蛋白的表达分别为2．63±0．40、3．02±0．52、2．98±0．36、5．54±0．28、3．26±0．13、1．05±0．33。PP2组、PP2＋VEGF—B组的MHCC97-H细胞E-钙黏蛋白和α-连环蛋白表达明显上调，PP2＋VEGF-B组与VEGF—B组比较，差异有统计学意义（t=7．625，9．931，P〈0．05）。PP2＋VEGF—B组的波形蛋白和N-钙黏蛋白的表达显著低于VEGF—B组（t=12．001，11．910，P〈0．05）。VEGF—B处理6h后，VEGF-B组、PP2＋VEGF-B组、PBS＋VEGF—B组的MHCC97-H细胞迁移数量分别为19±1、5±2和16±1，VEGF—B组MHCC97-H细胞迁移数量显著多于PP2＋VEGF—B组（t=13．566，P〈0．05），PP2＋VEGF-B组中MHCC97-H细胞穿过Matrigel包被的改良侵袭小室的数量为4±2，显著少于VEGF-B组的16±1（t=12．350，P〈0．05）。结论VEGFR-1活化诱导MHCC97-H细胞发生EMT是由c—Src激酶信号转导通路介导的，c—Sre作为该信号通路的关键因子之一可能是干预肝细胞癌侵袭和转移的有效靶点。

Objective To investigate the molecular mechanism of epithelial-mesenchymal transition （EMT） induced by activated vascular endothelial growth factor receptor-1 （VEGFR-1） in cell line MHCC97-H. Methods MHCC97-H cells were cultured in DMEM with 1% fetal bovine serum （control group）, 10μmol/L PP2 （PP2 group）, 10 μmol/L PBS （PBS group）, 50 μmol/L VEGF-B （VEGF-B group）, 10pLmol/L PP2 and 50 μmol/L VEGF-B （PP2 ＋ VEGF group）, 10 μmol/L PBS and 50 μmol/L VEGF-B （PBS ＋ VEGF-B group）,respectively. Protein expressions of epithelial marker E-cadherin, α-catenin and mesenchymal marker vimentin and N-cadherin were detected by Western blot. The expression sites of E-cadherin, α-catenin and mesenchymal marker vimentin and N-cadherin were detected by cell immunofluorescence. The ability of invasion and migration of cell line MHCC97-H were assessed by cell invasion and migration test. All data were analyzed by the t test. Results The expressions of E-cadherin, α-catenin, vimentin and N-cadherin were 3.23 ± 0.76, 3.01 ± 0.25, 3. 01 ±0.22 and 2.63 ±0.40 in the control group, 4.18 ±0.32, 3.29 ±0.11,4.85 ±0.36 and 3.02 ±0.52 in the PP2 group, 2.83 ±0.65, 3.03 ±0.27, 1.37 ±0.24 and 2.98 ±0.36 in the PBS group, 2.06 ±0.15, 2.84 ± 0. 76, 5.79 ± 0.38 and 5.54 ± 0.28 in the VEGF-B group, 6.12 ± 0.08, 5.45 ± 0.37, 3.36 ± 0.42 and 3.26 ± 0.13 in the PP2 ＋ VEGF-B group and 1.36 ± 0.54, 1.26 ± 0.45, 4.05 ± 0. 17 and 1.05 ± 0.33 in the PBS ＋ VEGF-B group. There was a significant difference in the expressions of E-cadherin and α-catenin between the PP2 ＋ VEGF-B group and the VEGF-B group （t =7. 625, 9. 931, P 〈0.05）. The expressions of vimentin and N-cad- herin in the PP2 ＋ VEGF-B group were significantly lower than those in the VEGF-B group （t = 12. 001, 11. 910, P 〈 0. 05 ）. Six hours after the treatment with VEGF-B, the numbers of MHCC97-H migrated were 19 ± 1, 5 ± 2 and 16 ± 1 in the VEGF-B group, PP2 ± VEGF-B group and PBS ＋ VEGF-B group, respectively. The number of MHCC97-H cells migrated in the VEGF-B group was greater than that in the PP2 -＋VEGF-B group （ t = 13. 566, P 〈 0.05 ）. The number of MHCC97-H cells passed through the Boyden chamber was 4 ± 2, which was significantly less than 16 ± 1 of the VEGF-B group （t = 12. 350, P 〈 0.05）. Conclusion EMT induced by activated VEGFR-1 was mediated via c-Src kinase signal transduction in MHCC91-H cell line, and c-Src may be a potential target to interfere the invasion and migration of hepatic cancer cells.