The effects of retinoblastoma gene therapy combined with radiotherapy on the retinoblastoma protein and Ki67 protein in carcinoma cells of tumor-bearing nude mice

WANG Qin; XU Chang; DU Li-qing; WANG Yan; SUN Zhi-juan; LI Jin; LIU Qiang

doi:10.3969/j.issn.1001-9448.2017.01.019

Abstract：Objective To reveal the effects of retinoblastoma 94 gene therapy combined with radiotherapy on the expression of Rb protein and Ki 67 protein in esophageal carcinoma cells of tumor -bearing nude mice .Methods The model of tumor-bearing nude mice was established by K 150 cells inoculation .The cohorts were divided into five groups , blank control (no treatment), Ad-LacZ group (control adenovirus including LacZ gene but not Rb 94 gene, Ad-LacZ was transfered into tumor xenograft on 0d , 3d , 7d therapy separately), Ad-Rb94 group (tumor xenograft was transfect-ed with Ad-Rb94 on 0d , 3d , 7d therapy separately), radiation group (tumor xenograft was irradiated with 4Gyγ-ra-diation on 1d, 4d, 8d therapy separately) and Ad-Rb94 combined with radiation group (combining group for short, tumor xenograft was irradiated with 4Gy after transfected with Ad-Rb94).The expression of Rb protein and Ki67 protein in esophageal carcinoma was detected by immunohistochemical analysis .Cell apoptosis was examined by TUNEL assay . Results The expression of Rb protein in Ad -Rb94 group ( 28.96 ±3.35%) and combining group ( 33.13 ±1.59%) was significantly increased compared with that in control group (q=9.96 and 13.35, P<0.05).The expression of Rb protein in Ad-Rb94 group and combining group was significantly higher than that in radiation group ( q =12.72 and 15.36, P<0.01).The expression of Ki67 protein in Ad-Rb94 group (29.15 ±1.65%), radiation group (38.16 ± 2.53%) and combining group ( 25.18 ±3.06%) was significantly reduced compared with that in control group ( q=6.36, 5.59 and 7.52, respectively, P<0.01).The expression of Ki67 protein in combining group was significantly less than that in radiation group (q=6.49, P<0.01).The ratios of cell apoptosis in Ad -Rb94 group (14.1 ±3.2%), ra-diation group (17.2 ±3.0%) and combining group (24.3 ±3.2%) were significantly increased compared with that in control group (q=6.62, 7.29 and 10.54, respectively, P<0.01).The ratio of cell apoptosis in combining group was significantly higher than that in radiation group or Ad -Rb94 group (q=6.36 or 7.89, P<0.01).Conclusion One mechanism of the synergism effects of retinoblastoma 94 gene therapy combined with radiotherapy on the inhibition of tumor growth is through increasing Rb protein expression and decreasing Ki 67 protein expression .