Liu Jian-lun, Wei Wei, Tang Wei, Jiang Yi, Yang Hua-wei, Li Jing-tao
Department of Breast Surgery, Cancer Hospital, Guangxi Medical University, Nanning 530021, China.
Zhonghua Yi Xue Za Zhi. 2012 May 29;92(20):1379-83.
To investigate possible mechanism of silencing lysyl oxidase (LOX) gene by RNA interference affecting on invasion and metastasis of breast cancer cells.
LOX-RNAi-LV was designed and synthesized, which was transfected into breast cancer cell line MDA-MB-231. The expressions of LOX, MMP-2 and MMP-9 were determined by Real-time PCR in MDA-MB-231 cells, and the protein expression of LOX was determined by Western blot. The cells migration and invasion abilities were measured by cell migration and invasion test. 111 cases of breast cancer tissue and cancer-adjacent breast tissues and 20 cases of benign lesion tissues of LOX, MMP-2 and MMP-9 were detected by immunohistochemistry, and the relationship of LOX and clinicopathological characteristics was analyzed.
The expression levels of LOX mRNA and protein were down-regulated obviously after transfecting LOX-RNAi-LV, with the inhibition rate 89.2% ± 1.3% and 84.4% ± 0.4% respectively. The relative expressions of MMP-2 and MMP-9 mRNA were 0.496 ± 0.021 and 0.571 ± 0.099 in RNAi group, which was significantly lower than that in negative control group (0.846 ± 0.047, 0.786 ± 0.042) and blank control group (1.000 ± 0.000, 1.000 ± 0.000) (both P < 0.05). Cell migration and invasion test showed the average cell numbers per field in the group RNAi were 47 ± 2 and 63 ± 2, was significantly lower than that in negative control group (100 ± 1, 118 ± 2) and blank control group (100 ± 1, 118 ± 2) (both P < 0.05). The expression of LOX protein in breast cancer, cancer-adjacent breast tissues and benign breast tumor were 48.6% (54/111), 26.1% (29/111), 20.0% (4/20), the expression of LOX protein in breast cancer was significantly higher than that in cancer-adjacent breast tissues and benign lesion tissues (P = 0.019). The expression of LOX protein was associated with clinical stage, lymph node metastasis, tumor size. Correlation analysis showed that LOX protein expression was significantly positive correlation with MMP-2 (r = 0.262, P = 0.005) and MMP-9 (r = 0.424, P = 0.000).
LOX can promote invasion and metastasis of breast cancer; LOX and MMP-2, MMP-9 may have a synergistic role in promoting invasion and metastasis of breast cancer.
探讨RNA干扰沉默赖氨酰氧化酶（LOX）基因影响乳腺癌细胞侵袭和转移的可能机制。
设计并合成LOX-RNAi-LV，转染至乳腺癌细胞系MDA-MB-231。采用实时荧光定量PCR检测MDA-MB-231细胞中LOX、基质金属蛋白酶-2（MMP-2）和基质金属蛋白酶-9（MMP-9）的表达，采用蛋白质免疫印迹法检测LOX蛋白表达。通过细胞迁移和侵袭实验检测细胞迁移和侵袭能力。采用免疫组织化学法检测111例乳腺癌组织及癌旁乳腺组织和20例乳腺良性病变组织中LOX、MMP-2和MMP-9的表达，并分析LOX与临床病理特征的关系。
转染LOX-RNAi-LV后，LOX mRNA和蛋白表达水平明显下调，抑制率分别为89.2%±1.3%和84.4%±0.4%。RNA干扰组MMP-2和MMP-9 mRNA的相对表达量分别为0.496±0.021和0.571±0.099，显著低于阴性对照组（0.846±0.047，0.786±0.042）和空白对照组（1.000±0.000，1.000±0.000）（均P<0.05）。细胞迁移和侵袭实验显示，RNA干扰组每视野平均细胞数分别为47±2和63±2，显著低于阴性对照组（100±1，118±2）和空白对照组（100±1，118±2）（均P<0.05）。乳腺癌组织、癌旁乳腺组织及乳腺良性肿瘤中LOX蛋白表达分别为48.6%（54/111）、26.1%（29/111）、20.0%（4/20），乳腺癌中LOX蛋白表达显著高于癌旁乳腺组织和良性病变组织（P=0.019）。LOX蛋白表达与临床分期、淋巴结转移、肿瘤大小有关。相关性分析显示，LOX蛋白表达与MMP-2（r=0.262，P=0.005）和MMP-9（r=0.424，P=0.000）呈显著正相关。
LOX可促进乳腺癌的侵袭和转移；LOX与MMP-2、MMP-9在促进乳腺癌侵袭和转移中可能具有协同作用。
