The Expression Of Indoleamine 2,3-dioxygenase-1 (IDO1) In Lung Cancer And Its Correlation To Angiogensis

Objective:To explore the expression of IDO1 in lung cancer tissue and the ralatonship between IDO1 level and angiogenesis in tumor microenviroment,which would provide new insight for cancer therapy.Methods:1.41 cases of lung cancer paraffin tissue samples were collected from the Second Affiliated Hospital of Nanchang University during 2013 to 2014.In order to seek the relationship between IDO1,CD31,CD34 and Factor Ⅷ,immunohistochemistry was used to detect the expression of them.Meanwhile,the relationship between IDO1 and clinicopathologic factors and prognosis was also investigated.2.A lung cancer cell line,A549 cells,were transfected with the eukaryotic expression plasmid pc DNA3 IDO1 by lipofectamineTM 2000.And the expression of IDO1 was proved by using Western blotting.The effects of pc DNA3/IDO1 on proliferation of A549 cells were detected.The cell invasion ability of A549 was explored by cell invasion assay.3.A co-cultured system of pc DNA3/IDO1-A549 and HUVEC was established.The effects of pc DNA3/IDO1 on the proliferation of HUVEC were detected by MTT and the formation of vessel-like structures of HUVEC was observed in vitro.Then the expression of VEGF were measured by both ELISA and q PCR.4.Statistical analysis: Data from independent experiments were expressed as Mean±SD,and data from small samples were transformed by Lg10 before statistical processing.The t test analysis was taken when needed using the statistical software of SPSS19.0.Results:1.Immunohistochemistry results show that the high expressing ratio of IDO1 in lung cancer was 60.9% and the low or negative expression ratio of IDO1 in lung cancer was 39.1%.There was a positive correlation between the expression of IDO1 and CD34 and Factor Ⅷ positive MVD(r=0.333,r=0.342),but not CD31 positive MVD in lung cancer.2.Western blotting results show that the over-expression ratio of IDO1 is 41.6% in transfected A549 cell.3.MTT experiments show that the proliferation of cells in the transfected group which overexpressed IDO1 was significantly higher than cells in control group and empty plasmid transfection group.4.Invasion assay indicated that cells in the IDO1 transfected group was significantly more invasive than cells in control group and the empty plasmid transfection group.5.HUVECs co-cultured with pc DNA3/IDO1-A549 resulted in proliferation of HUVECs.6.Matrigel matrix experiments show that the formation of vessel-like structures of HUVEC was promoted.The formation of vessel-like structures of HUVEC to begin at 6h and peaked at 12 h,then gradually disappeared at 24 h.7.VEGF m RNA and secrection remarkably increased with time in HUVECs from the co-cultured system of pc DNA3/IDO1-A549 and HUVEC,when compared with the other two groups.Conclusions:1.There was a positive correlation between the expression of IDO1 and CD34 and Factor Ⅷ positive MVD,but not CD31 positive MVD in lung cancer.2.The biological characteristics were change by IDO1 overexpression,which promoted the proliferation and invasion ability.3.Co-culture of pc DNA3/IDO1-A549 with HUVEC resulted in increased expression and secretion of VEGF as well as the formation of vessel-like structures.