ABSTRACT
Objective To investigate the effect of retinoblastoma binding protein 4 (RBBP4)in Sp1 -mediated HIV long terminal repeat(LTR)transcription.Methods RBBP4 expression vector and Sp1 expression vector were respectively co-transfected into 293 T cells with HIV promoter pHIV-LTR-Luc or Sp1 site mutated pHIV-LTR-sp1 -mut by liposome transfection,and the transfected cells were examined by dual luciferase reporter assay system.The effect of RBBP4 on the binding of Sp1 to LTR was further studied by chromatin immunoprecipitation (ChIP)and electrophoretic mobility shift assay (EMSA).Results The relative firefly luciferase activity activated by Sp1 was decreased from 62.5 to 16 at the dose of 500 ng of RBBP4 expression vector (t =14.52,P <0.01 ).When the Sp1 binding sites were mutated,the effects of 100,300 or 500 ng of RBBP4 expression vector on the firefly luciferase activity of HIV LTR were not statistically significance (t =1 .897,2.357 and 3.162,all P <0.05).ChIP results showed that when the binding of RBBP4 on HIV LTR increased,the binding of Sp1 on HIV LTR increased significantly (t =11 .93,P <0.01 ),while the reduced binding of RBBP4 on HIV LTR significantly attenuated the binding of Sp1 onto LTR(t =11 .38,P <0.01 ).The effect of RBBP4 on the binding of Sp1 to DNA in ChIP assays was further verified by EMSA assays.Conclusion RBBP4 can inhibit the Sp1 -mediated HIV LTR transcription in 293 T cells.
ABSTRACT
Objective To explore the value of retinoblastoma binding protein 4 ( RBBP4 ) in diagnosing prostate cancer ( PCa).Methods From January 2015 to December 2015, the prostate tissue after prostatectomy were collected and the differentially expressed degree of RBBP4 protein was analyzed in PCa and adjacent tissues by 2D-DIGE technology.The RBBP4 score of prostate tissue chip which contains 3 normal prostate tissues, 7 cancer adjacent normal prostate tissues, 50 adenocarcinoma and 20 hyperplasia tissue was checked by immunohistochemistry( IHC).In 50 patients with PCa, 4 cases were less than 60 years old and 46 cases were more than 60 years.In those patients, the Gleason scores were less than 7 scores in 18 cases, and more than 7 scores in 30 cases.22 cases were confirmed less than Ⅱ stage, and 28 cases were confirmed more than Ⅲ stage.Finally, the RBBP4 IHC score and the clinic-pathological parameters such as age, Gleason score and clinical stage of PCa patients were analyzed together.Results We found that the protein of RBBP4 increased by 2.15 times in PCa tissues compared to adjacent tissues by using 2D-DIGE technology( P=0.008).The expression of RBBP4 was higher than that in benign tissues by IHC ( F=43.972,P=0.000).And the expression of RBBP4 was positive correlation with Gleason score( t=5.589, P=0.000) and clinical stage(t=5.620,P=0.000), but was negative correlation with age(t=1.125,P=0.266).Conclusions The detection of RBBP4 can help to separate PCa from benign tissues.The overexpression of RBBP4 might result in the rapid growth of malignant cells.It may have certain value in determine the clinical staging and pathological grading of PCa.