The effect of RNF2 knockdown on the radiosensitivity in transplanted tumor of nude mice of esophageal carcinoma in vivo
Yang Xingxiao1,Zhang Xueyuan2,Li Qiaofang2,Ma Ming3,Liu Zhikun2,Zhu Shuchai2
1Department of Infection Management, Fourth Affiliated Hospital of Hebei Medical University, Shijiazhuang 050011,China; 2Department of Radiation Oncology, Fourth Affiliated Hospital of Hebei Medical University, Shijiazhuang 050011,China; 3Department of Laboratory, Fourth Affiliated Hospital of Hebei Medical University, Shijiazhuang 050011,China
Objective To evaluate the effect of RNF2 gene knockdown in ECA109 cells on the radiosensitivity to esophageal cancer cell xenograft in nude mice. Methods Thirty-six male BALB/c/nu nude mice were randomly divided into 6 groups:control group, control+ irradiation group, NC group,NC+ irradiation group,RNF2 shRNA group and RNF2 shRNA+ irradiation group. The nude mouse models with transplanted tumors were established by subcutaneous inoculation of EAC109 cells and given with irradiation at a dose of 3 Gy for 5 times. The longest (a) and shortest (b) diameters of the transplanted tumor were measured every 2 to 3 day sincethe fourteenth dayafter inoculation. The time of tumor formation was recorded. The tumor volume was calculated according to the formula (ab2/2). The growth curve was delineated. Three nude mice were sacrificed in each group at 24 h after the initial irradiation. The expression of RNF2 at the mRNA and protein levels in transplanted tumor tissues was measured by qRT-PCR and immunohistochemistry, respectively. The growth and tumor volume of the other nude mice in each group were observed. The cell apoptosis of transplanted tumor tissues was detected by TUNEL assay. The expression of Bcl-2 and Bax at the mRNA and protein levels in transplantated tumor tissues was quantitatively measured by qRT-PCR and immunohistochemistry, respectively. Results The tumor growth rate was the highest in the control and NC groups. The knockdown of RNF2 reduced the growth rate of xenografts and the tumor growth rate was the slowest in the RNF2 shRNA+ irradiation group (P<0.05). TUNEL assay revealed that the cell apoptosis rates in all groups were significantly increased after irradiation (all P<0.05). Before and after irradiation, the apoptosis rate in the RNF2 shRNA group was markedly higher than those in the control and NC groups (both P<0.05). Prior to irradiation, the expression levels of RNF2 mRNA and protein in the RNF2 shRNA group were significantly lower compared with those in the control and NC groups (all P<0.05), and the tendency became more significant after irradiation. Compared with the control and NC groups, the expression levels of Bcl-2 mRNA and protein were significantly down-regulated in the RNF2 shRNA group before and after irradiation (all P<0.05), whereas those of Bax mRNA and protein were considerably up-regulated (all P<0.05). ConclusionsIn vivo experiment demonstrates that RNF2 knockdown effectively increases the radiosensitivity of esophageal carcinoma EAC109 cells in nude mouse models with transplanted tumors, which is intimately associated with inducing the cell apoptosis.
Yang Xingxiao,Zhang Xueyuan,Li Qiaofang et al. The effect of RNF2 knockdown on the radiosensitivity in transplanted tumor of nude mice of esophageal carcinoma in vivo[J]. Chinese Journal of Radiation Oncology, 2019, 28(8): 612-615.
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2019, Vol. 28 
