The Study Of HLA Class I Molecules Expression And TAP1,TAP2,LMP2,LMP7 In Colorectal Tumor Cell

ObjectiveTo construct the real time-PCR method for detecting TAP1,TAP2,LMP2,LMP7 mRNA in cells of tumor tissues and normal mucosa.The expression of HLA-Ⅰwas also measured.To explore the mechanism of HLA-Ⅰdo wnregulated in tissues of patients with colorectal caner.METHODS1.The method was established for detecting TAP1,TAP2,LMP2,LMP7 mRNA using ABI7500 real time PCR.In this new method,β-actin was introreference and normal mucosa tissue was control.2.S-P immunohistochemistry was used to detect the expression of HLA-Ⅰin cells of tumor tissues and normal mucosa.To analyze the relationship between HLA-Ⅰexpression and different Dukes,degree of differentiation.3.TAP1,TAP2,LMP2 and LMP7 mRNA were measured in tissues of 74 colorectal caner patients using two step RT-PCR.To explore the relationship between TAP1,TAP2,LMP2 and LMP7 mRNA and HLA-Ⅰexpression.All the data were analyzed by SPSS 13.0 Software.RESULTS1.HLA-Ⅰwas all positive in 74 normal mucosa tissues of colorectal caner and only 39.2%was positive in tumor tissues.There was statistical difference in this two groups(P<0.001).2.TAP1,TAP2,LMP2 and LMP7 mRNA were significantly lower in tumor tissue than in normal mucosa tissue.Pvalue were respectively 0.0010,0.0010,0.0010,0.0010.3.TAP1,TAP2,LMP2 and LMP7 mRNA were lower in colorectal cancer patients of HLA-Ⅰnegative group than in HLA-Ⅰpositive group.4.TAP1,TAP2,LMP2 and LMP7 mRNA decreased progressively with the grades of tissue differentiation.There were statistical difference between TAP1,LMP2 mRNA in poor -differentiation group and in mid-differentiation group,in high- differentiation group(P<0.05).There were only decreased trend for TAP2and LMP7 mRNA in different differentiation groups,but there were no statistical difference(P>0.05)5.The expression of TAP1,TAP2,LMP2 and LMP7 mRNA only had the decreased trend in different Dukes stages but there were no statistical difference(P>0.05)6.The expression of HLA-Ⅰhad the positive correlation with TAP1,TAP2,LMP2 and LMP7 mRNA in tissues of colorectal cancer patients(r value were respectively0.8576,0.8258,0.8223,0.7818).CONCLUSION1.The two step RT-PCR was successfully established for detecting TAP1,TAP2,LMP2,LMP7 mRNA.The specific primer was designed using Prime 5.0 Software and the reaction system was optimized.2.The expression of HLA-Ⅰlost in most colorectal cancer tissues.The loss of HLA-Ⅰplayed an important role in the tumorigenesis and development of colorectal caner.3.TAP1,TAP2,LMP2,LMP7 mRNA were significantly decreased in tumor tissues of HLA-Ⅰnegative patients and they were progressively decreased as poorer tissue differentiation.4.The expression of HLA-Ⅰhad the positive correlation with TAP1,TAP2,LMP2 and LMP7 mRNA in tissues of colorectal cancer patients.This indicated there decreased expression of HLA-Ⅰin tissues of colorectal caner patients might caused by TAP1,TAP2,LMP2 and LMP7 mRNA.