ABSTRACT
AIM: To observe the effect of exogenous androgen responsive element decoy on the promoter of prostate specific antigen (PSA) and the growth of LNCaP cells for searching the possibility of gene therapy for prostate cancer. METHODS: Firstly, pGL3 - PSA luciferase expression vector containing 640bp - promoter fragment of PSA gene was constructed. Then, a 23 -mer phosphorothioated ARE decoy based on the deduced ARE sequence at the promoter region of PSA gene was synthesized. pGL3 - PSA and ARE decoy DNA were cotransfected into PC3 - M cell by lipofectamineTM 2000. Through detecting the activity of luciferase, the effect of ARE decoy on the promoter of PSA was studied. Then the ARE decoy DNA was transfected into LNCaP cells. The effect of decoy DNA on the proliferation of LNCaP cells was examined by using MTT assay. The effects of apoptosis were detected by phase contrast microscopy, DNA agrose gel electrophoresis and flow cytometry. Meanwhile, the nuclear extract was prepared from LNCaP cells and DNA - protein interactions were examined by electrophoretic mobility shift assay (EMSA). RESULTS: The reporter assay showed that the aetivity of luciferase was significantly reduced in the ARE decoy - transfected cells, bnt not in the cells transfected with the control decoy. EMSA demonstrated specific binding of the ARE decoy to androgen receptor. The growth of LNCaP was remarkably inhibited and apoptotic morphological changes as well as DNA fragmentation were observed in the ARE decoy- transfected cells. The rate of apoptosis was 22.4% detected by FCM. CONCLUSION: The ARE decoy is capable of inhibiting the promoter of PSA gene and inducing the apoptosis in prostate cancer cells. It may become a potential therapeutic tool for prostate cancers.
ABSTRACT
AIM: To study the basic mechanism of transcriptional regulation, NKX3.1 gene promoter was cloned and its promoter activities in prostate cancer cell lines and other cancer cell lines were tested. METHODS: 1.04 kb - promoter fragment of NKX3. 1 gene was obtained by PCR and cloned into pGL3 - basic and pEGFP - 1 that are promoter - less reporter vectors to examine its promoter activity driving the reporter gene transcription. The promoter activity was determined by dual -luciferase reporter assay and the expression of GFP reporter observed under fluorescence micro scope. RESULTS: The sequence of the cloned 1.04 kb promoter proved to be correct by DNA sequencing. The dual - lu ciferase reporter assay (M1/M2) showed that the promoter activity in LNCaP cell transfected with pGL3 - 1.04 kb promoter was about 1.5 - fold higher than that of pGL3 - control transfection and 50 - fold higher than that of pGL3 - basic transfec tion. To investigate the 1.04 kb - promoter activity in different tumor cell lines, the constructed pGL3 - 1.04 kb promoter and pEGFP - 1.04 kb promoter were transfected into several cell lines, respectively. The results showed that the activity of 1.04 kb promoterin LNCaP was highest among the tested cell lines. Multiple consensus sequence elements have been iden tified within the 1.04 kb fragment using TRANSFAC database. Further experiments will be done to determine their founc tions. CONCLUSION: Cloned 1.04 kb fragment upstream of NKX3.1 gene presented a strong promoter activity and its activity was highest in LNCaP cell among the tested tumor cell lines.
ABSTRACT
AIM: To study the basic mechanism of transcriptional regulation,NKX3.1 gene promoter was cloned and its promoter activities in prostate cancer cell lines and other cancer cell lines were tested.METHODS:(1.04 kb)-promoter fragment of NKX3.1 gene was obtained by PCR and cloned into pGL_3-basic and pEGFP-1 that are promoter-less reporter vectors to examine its promoter activity driving the reporter gene transcription.The promoter activity was determined by dual-luciferase reporter assay and the expression of GFP reporter observed under fluorescence microscope.RESULTS: The sequence of the cloned(1.04 kb) promoter proved to be correct by DNA sequencing.The dual-luciferase reporter assay(M1/M2) showed that the promoter activity in LNCaP cell transfected with pGL_3-(1.04 kb) promoter was about 1.5-fold higher than that of pGL_3-control transfection and 50-fold higher than that of pGL_3-basic transfection.To investigate the 1.04 kb-promoter activity in different tumor cell lines,the constructed pGL_3-(1.04 kb) promoter and pEGFP-1.04 kb promoter were transfected into several cell lines,respectively.The results showed that the activity of(1.04 kb) promoter in LNCaP was highest among the tested cell lines.Multiple consensus sequence elements have been identified within the(1.04 kb) fragment using TRANSFAC database.Further experiments will be done to determine their founctions.CONCLUSION: Cloned 1.04 kb fragment upstream of NKX3.1 gene presented a strong promoter activity and its activity was highest in LNCaP cell among the tested tumor cell lines.
ABSTRACT
AIM: To observe the effect of E2F decoy DNA on proliferation and apoptosis of androgen-independent prostate cancer cell line PC-3M.METHODS: E2F decoy DNA,ARE decoy DNA and control decoy DNA were transfected into PC-3M cells with lipofectamine,respectively.Their effects on cell proliferation were detected by MTT assay.The changes of cell morphology were observed by inverted phase contrast microscope.The cell apoptotic rate was determined by flow cytometry(FCM) analysis and chromosome DNA ladder was detected by DNA gel electrophoresis.The expression of c-Myc mRNA and cyclin D1 mRNA was detected by RT-PCR.The protein levels of c-Myc and cyclin D1 were detected by Western blotting.RESULTS: The growth of PC-3M cells was inhibited after transfection.The transfected PC-3M cells displayed typical apoptotic morphological changes.The apoptotic rate was 26.35% and DNA ladder was observed after transfection.The expression of c-Myc and cyclin D1 were inhibited.CONCLUSION: These results indicate that E2F decoy DNA induces apoptosis of androgen-independent prostate cancer cell lines PC-3M and inhibits cell proliferation via inhibiting expression of c-Myc and cyclin D1.