中期因子低表达对前列腺癌细胞增殖、侵袭及基质金属蛋白酶-9表达的影响

Effects of midkine gene low-expression on proliferation and invasion of prostate cancer and matrix metalloproteinase-9 gene expression

目的观察降低中期因子（MK）表达对人前列腺癌PC-5细胞增殖、侵袭及基质金属蛋白酶-9基因（MMP-9）表达的影响。方法用浓度为10nmol／L的MK基因小干扰RNA（siRNA）转染人前列腺癌PC-3细胞株，应用逆转录-聚合酶链反应（RT—PCR）方法检测MK和MMP-9mRNA水平，Transwell法和噻唑蓝（MTT）法检测PC-5细胞侵袭和增殖能力，平板克隆形成实验检测PC-3细胞克隆形成能力。结果与对照组比较，MK—siRNA组MK、MMP-9mRNA水平明显降低（P〈0．05）。Transwell实验结果显示，MK—siRNA组穿过滤膜的细胞数为（329．17±10．65）个，明显少于空白对照组[（580．00±10．20）个，P〈0．01]及空载对照组[（575．67±11．54）个，P〈0．01]。MTT法检测显示，MK—siRNA组细胞增殖受到抑制。平板克隆实验显示：MK—siRNA组克隆形成率为（35．33±2．80）％，低于空白对照组[（71．42±1．11）％，P〈0．01]。结论降低MK基因表达能抑制人前列腺癌PC-3细胞的侵袭及增殖，下调MMP-9基因表达，可能是其分子机制之一。

Objective To observe the effects of down-regulation of midkine （MK） gene expression on proliferation and invasion of prostate cancer PC-3 cells and matrix metalloproteinase （MMP） -9 gene expression. Methods After human prostate cancer PC-3 cells were transfected with midkine small interfering RNA （siRNA） at the concentration of 10 nmol/L, the mRNA expression levels of midkine and MMP-9 were examined by reverse transcription-polymerase chain reaction （RT-PCR）. The invasion and proliferation ability was determined by Transwell and methyl thiazol tetrazolium （ MTT ） assay respectively. The PC-3 cell clony formation ability was evaluated by plate colony formation assay. Results As compared with the control group, the mRNA expression levels of midkine and MMP-9 gene were greatly inhibited in prostate cancer PC-3 cells transfected with MK-siRNA （ P 〈 0. 05 ）. Transwell assay showed that the nmnber of PC-3 cells penetrating the membrane in the siRNA group （329. 17 -10. 65 ） was greatly decreased as compared with the Con-A group （580. 00 ± 10. 20,P 〈 0. 01 ） and Con-B group （575.67 ± 11.54, P 〈 0.01 ）. MTT assay showed that the cell proliferation was significantly inhibited in MK-siRNA group. The result of plate colony formation assays showed that the colony formation rate in the siRNA group [ （35.33 ± 2.80） % ] was significantly decreased as compared with Con-A group [ （71.42 ± 1. 11 ） % ] （ P 〈 0. 01 ）. Conclusion Down-regulation of midkine gene can inhibit the invasion and proliferation of prostate cancer cells through down-regulation of MMP-9 gene.