LOX, MMP-2, MMP-9, HIF-1α Protein In Experimental Studies Of Breast Cancer Invasion/Metastasis

Objective:To explore LOXmRNA expression in breast cancer cell lines which have different invasive/metastatic potential. Observing the tumour growth and metastasis in breast cancer model. Compare the LOX, MMP-2, MMP-9 and HIF-1αprotein expression in breast cancer model.Analyze the correlation between LOX and MMP-2, MMP-9, HIF-1α.Detect the LOX, MMP-2, MMP-9 protein in breast cancer tissues and analyze the clinical data.Methods:1.The expression of LOXmRNA was detected by RT-PCR (reverse transcription-PCR,RT-PCR) in breast cancer cell lines MDA-MB-231 and MCF-7.2.MDA-MB-231, MCF-7,MDA-MB-231(RNAi) cell were used to establish the breast cancer model.Observe the general situation,tumor size and weight of the nude mice.On the seventh week the tumor was resected and check for internal organ metastasis.The S-P immunohistochemical method was used to detecte the expression of LOX, MMP-2, MMP-9, HIF-1αin transplanted tumor,then the data were analyzed statistically. 3.Collecting 111 cases of breast cancer tissues,which were diagnosed with invasive ductal carcinoma.The immunohistochemical method was used to detecte the expression of LOX, MMP-2, MMP-9,then analyzed statistically with the clinical data.Results:1.The highly invasive/metastatic breast cancer cell line MDA-MB-231 had a much higher LOXmRNA expression level than that of breast cancer cell line MCF-7 (P<0.01).2.The tumor occured after inoculation in all the mice and was resected after 6 weeks.The tumor volume and weight of MDA-MB-231 group were significantly greater than that of MCF-7 group (P=0.000) or MDA-MB-231 (RNAi) group (P=0.000),while there was no difference between MCF-7 group and MDA-MB-231 (RNAi) group (P>0.05).Three nude mice were diagnosed with lung metastasis in MDA-MB-231 group while the other two groups were not.3.LOX, MMP-2, MMP-9 and HIF-1αprotein expresson level in MDA-MB-231 group was significantly higher than that of MCF-7 group (P=0.000) or MDA-MB-231 (RNAi) group (P=0.000),while there was no difference between MCF-7 group and MDA-MB-231 (RNAi) group (P> 0.05).LOX protein had a positive correlation with MMP-2(r=0.696,P=0.000),MMP-9(r=0.735, P=0.000),HIF-1α(r=0.737, P=0.000) protein in transplanted tumor.4.The expression of LOX from breast cancer tissues was associated with clinical stage (P=0.000), lymph node status (P=0.003) and tumor size (P=0.000),but had no correlation with age (P>0.05).The LOX protein had a significant positive correlation with MMP-2 (r=0.262, P=0.005), MMP-9 (r=0.424, P=0.000) in breast cancer tissues.There was significant negative correlation between LOX protein and ER (r=0.257,P=0.007), PR (r=0.276, P=0.003),HER-2 (r=0.225, P=0.017) protein.Conclusion:1.The highly invasive/metastatic potential of breast cancer may be related to the high expression of LOX, MMP-2, MMP-9, HIF-1αand the cooperative effect from each other.2.LOX may had the same mechanism with MMP-2, MMP-9 in breast cancer invasion/metastasis,LOX may be subject to the regulation of HIF-1α3.LOX expression may be related to tumor size,clinical stage,lymph node metastasis,but not the patient's age.4.LOX expression may be related to ER,PR,HER-2 expression.