Abstract: Objective: To study the inhibitory effect of retinoblastoma 94(Rb94) gene combined with radiotherapy ionizing radiation on the growth of esophageal carcinoma cells of tumor-bearing nude mice, and to clarify the synergistic effect of Rb94 gene and radiotherapy in inhibiting the growth of tumor cells. Methods: The models of tumor-bearing BALB/c-nu nude mice were built by inoculating the K150 cells. The model mice were divided into five groups:blank control(no any treatment), Ad-LacZ(control adenovirus including LacZ gene but not Rb94 gene, Ad-LacZ was transfered into tumor xenograft on 0, 3, 7 d separately), Ad-Rb94(tumor xenograft was transfected with Ad-Rb94 on 0, 3, 7 d separately), radiation (tumor xenograft was irradiated with 4 Gy γ-radiation on 1, 4, 8 d separately) and Ad-Rb94 combined with radiation(combination group, tumor xenograft was irradiated with 4 Gy γ-radiation after transfected with Ad-Rb94) groups. The volumes and the weights of esophageal carcinoma and the inhibitory rates of tumor growth of the mice in various groups were detected. The expression levels of ABL and JNK kinase in tumor tissue of the mice in various groups were measured,and the pathological changes of tumor tissue were investigated. Results: The speeds of tumor growth of the nude mice in Ad-RB94, radiation, and combination groups were slower than that in control group. The volume of esophageal carcinoma in combination group at day 15 after treatment was markedly smaller than those in Ad-RB94 and radiation groups,and there were significant differences compared with control group and Ad-LacZ group (F=26.7,23.8;P<0.01). The tumor weight of the nude mice in combination group was the lightest at the end of treatment; the inhibitory rate of tumor growth in combination group reached 81.16% and was significantly higher than those in Ad-Rb94 group(57.84%)and radiation group(38.20%)(P<0.01). The expression levels of ALB and JNK kinase in tumor tissue of the mice in combination group was markedly higher than those in control group(P<0.01). Compared with other groups, the tumor cells in combination group had fewer karyokinesis and lower level of nuclei hyperchromasia. Conclusion: Rb94 gene combined with radiotherapy shows synergistic effect in inhibiting the growth of tumor of tumor-bearing nude mice.

Key words: retinoblastoma 94 gene, tumor-bearing nude mice, esophageal neoplasms, radiotherapy