ABSTRACT
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 since the fourteenth day after 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 ) . Conclusions In 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.
ABSTRACT
Objective To examine the effect of X-ray radiotherapy on cell proliferation, migration, apoptosis, and cell cycle of human esophageal carcinoma ECA-109 cells following RNA interference (RNAi)-mediated downregulation of RNF2 gene expression.Methods The level of RNF2 mRNA expression in the human esophageal carcinoma cell line ECA-109 was determined using RT-PCR.Cell proliferation of ECA-109 was measured by MTT assay, and the changes in RNF2 protein expression in ECA-109-R cells were determined using Western blot.The changes in cell cycle and cell apoptosis at different time points following radiation were analyzed by flow cytometry, and the effect of transduction on cell migration was examined using Transwell migration assay.Data were subjected to an analysis of variance with repeated measurement design.Results The mean mRNA and protein levels of RNF2 in ECA-109 cells were significantly increased in a dose-dependent manner in the radiation group than in the control group (P0.05).The Transwell migration assay showed that the number of migrating cells following 3.5 h of radiation was significantly lower in the ECA-109-R group than in the ECA-109 and ECA-109-N groups (P<0.01).The percentage of G2/M phase cells in each group was significantly lower following 6 Gy radiation compared to that in the corresponding untreated group (P<0.01), and the percentage of G2/M phase cells was significantly lower in the ECA-109-R group than in the ECA-109 and ECA-109-N groups (P<0.05).Furthermore,cell apoptosis following radiation was also significantly higher in the ECA-109-R group than in the ECA-109 and ECA-109-N groups (P<0.01).Conclusions RNAi-mediated downregulation of RNF2 expression in esophageal carcinoma cells can reduce cell proliferation and cell migration, rescue post-radiation G2/M cell cycle arrest, promote cell apoptosis,and increase radiosensitivity.
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Purpose To investigate the expression of RNF2 in breast disease tissues and cell lines,and to analyze the association between expression of RNF2 and clinicopathological characteristics in breast carcinoma.Methods Expression of RNF2 protein and mRNA levels was detected using immunohistochemistry of EnVision two-step and qRT-PCR in breast carcinoma and benign breast disease as well as in cell lines.Results RNF2 expression was sigmificantly higher in breast carcinoma tissue specimens compared with benign breast disease specimens (P ＜0.05).Besides,the expression of RNF2 protein was significantly associated to tumor size,lymph node status and TNM stage (P ＜ 0.05 for both),but was not related to age,histological grade,the expression of ER,PR and HER-2 (P ＞ 0.05 for both).Higher expression of RNF2 mRNA was detected in breast carcinoma cell lines compared with breast epithelial cell lines (P ＜ 0.05).Conclusion RNF2 is overexpressed in breast carcinoma and can be a potential therapeutic target for breast carcinoma.