分泌性白细胞蛋白酶抑制剂对结肠癌细胞侵袭的影响及机制

Effect of secretory leukocyte protease inhibitor on colon cancer cell invasion and its mechanism

目的探讨分泌性白细胞蛋白酶抑制剂(secretory leukocyte protease inhibitor,SLPI)对结肠癌细胞侵袭能力的影响及可能分子机制.方法取对数生长期人结肠癌SW480细胞,随机分为SLPI过表达组(转染SLPI过表达质粒pCMV6-SLPI)、空白组(转染空载质粒)、抑制剂组(转染pCMV6-SLPI及特异性Wnt/β-catenin信号通路抑制剂ICG-001);转染后培养24 h,采用流式细胞术检测3组SLPI阳性细胞率,采用Transwell小室法检测3组细胞侵袭能力,Western bolt法检测β-catenin、T细胞因子-4(T cell factor-4,TCF-4)蛋白相对表达量,ELISA法检测基质金属蛋白酶-7(matrix metalloproteinase-7,MMP-7)水平.结果转染后培养24 h,SLPI过表达组、抑制剂组SLPI阳性细胞率[(94.98±1.71)%、(93.88±2.43)%]均高于空白组[(25.70±2.39)%](P<0.05),SLPI过表达组与抑制剂组比较差异无统计学意义(P>0.05);SLPI过表达组侵袭细胞数[(133.75±14.85)个]高于空白组[(107.75±7.54)个]、抑制剂组[(46.13±6.81)个](P<0.05),空白组高于抑制剂组(P<0.05);转染后培养24 h,SLPI过表达组β-catenin相对表达量(0.90±0.22)、TCF-4相对表达量(0.81±0.25)及MMP-7[(1 716.29±459.82) ng/L]水平均高于空白组[0.51±0.06、0.50±0.04、(1 386.07±542.53) ng/L]、抑制剂组[0.25±0.02、0.18±0.02、(174.96±55.57)ng/L](P<0.05),且空白组高于抑制剂组(P<0.05).结论 SLPI通过活化Wnt/β-catenin通路促进MMP-7表达,增强结肠癌细胞侵袭能力.

Objective To investigate the effect of secretory leukocyte protease inhibitor(SLPI) on colon cancer cell invasion and its molecular mechanism. Methods SW480 cells in logarithmic growth phase were randomly divided into SLPI overexpression group transfected with pCMV6-SLPI, blank group transfected with empty vector and inhibitor group transfected with pCMV6-SLPI and Wnt/β-catenin inhibitor ICG-001. After 24 h of transfection, the SLPI positive rate were detected by flow cytometry, the invasion capacity was detected by Transwell system, the relative expressions of β-catenin and T cell factor-4(TCF-4) were detected by Western blot, and matrix metalloproteinase-7(MMP-7) level was detected by ELISA technique. Results After transfection for 24 h, the positive rate of SLPI cells was significantly higher in SLPI overexpression group((94.98±1.71)%) and inhibitor group((93.88±2.43)%) than that in blank group((25.70±2.39)%)(P<0.05), and showed no significant difference between SLPI overexpression group and inhibitor group(P>0.05). The cell invasion count decreased gradually in SLPI overexpression group(133.75±14.85), blank group(107.75±7.54) and inhibitor group(46.13±6.81) in turn(P<0.05). The levels of β-catenin, TCF-4 and MMP-7 decreased gradually in SLPI overexpression group(0.90±0.22, 0.81±0.25,(1 716.29±459.82) ng/L), blank group(0.51±0.06, 0.50±0.04,(1 386.07±542.53) ng/L) and inhibitor group(0.25±0.02, 0.18±0.02,(174.96±55.57) ng/L) in turn(P<0.05). Conclusion SLPI improves the MMP-7 expression by activating Wnt/β-catenin signaling pathway to enhance the invasive ability of colon cancer cells.