Androgen responsive element decoy DNA inhibits the promoter of prostate specific antigen and induces apoptosis of LNCaP cells

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 activity 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.     

Expression of SAL-like 4 protein in human prostate cancer tissue/cell lines and its relationship with clinical outcome

AIM:To evaluate the expression of SAL-like 4 (SALL4) protein in human prostate cancer cell lines and tissues, and to analyze the relationship between SALL4 expression and the clinicopathological parameters. METHODS:Immunofluorescence, RT-PCR and Western blotting were performed to detect the expression of SALL4 at mRNA and protein levels in 3 common prostate cancer cell lines LNCaP, DU145 and PC-3. The normal prostate epithelial cell line RWPE-1 was used for control. The protein levels of SALL4 in the tissues of benign prostate hyperplasia and prostate cancer tissues were determined by the method of immunohistochemistry. RESULTS:The SALL4 protein was predominantly expressed in the cytoplasm of the cells. The protein levels of SALL4 in 3 common prostate cancer cell lines were significantly higher than that in RWPE-1 cells. However, the mRNA level of SALL4 had no obvious difference among the 4 cell lines. Immunohistochemistry results showed that the expression level of SALL4 in the cancerous tissues was significantly higher than that in noncancerous (benign and normal) prostatic tissues. In addition, we found that the expression level of SALL4 in prostate cancer was significantly correlated with the Gleason score, clinical stage, prognosis estimation and tissue prostate-specific antigen (PSA) expression, but not associated with age, the level of serum total PSA, prostate volume and the expression of androgen receptor in the tissues of the patients. CONCLUSION: The over-expression of SALL4 protein may play an important role in the pathogenesis and progression of prostate cancer, and provides some reference indexes for estimating the malignancy, progression and prognosis of prostate cancer.     

Effect of curcumin on the proliferation and apoptosis in LNCap cells

AIM:To observe the effect of curcumin on the proliferation and apoptosis of prostate cancer cell line LNCap. METHODS:LNCap cells were treated with different doses (10 μmol/L, 20 μmol/L, 30 μmol/L, 40 μmol/L) of curcumin and its effects were analyzed in cell growth and apoptosis by microscope, MTT colorimetric assay and flow cytometry. The expression of prostate specific antigen (PSA) was measured by AXSYMTM system-chemical luciferase methods and expression of androgen receptor (AR) was detected by Western blotting. RESULTS:The results showed that curcumin inhibited the proliferation of LNCap cells. The cell growth was inhibited by curcumin in a dose dependent manner and the optimal dose and time was 40 μmol/L, 24 h. Curcumin induced apoptosis in LNCap cells, the most dramatic dose was 40 μmol/L curcumin, at this dose the apoptosis rate was 9.23%. Curcumin inhibited the expression of PSA in LNCap cells and the most dramatic dose and time was 40 μmol/L, 24 h. The PSA in this group was 20% of the control group. Curcumin inhibited the expression of AR on prostate cancer cells. CONCLUSION:Curcumin decreases proliferation and induces apoptosis in LNCap cells in a dose-dependent manner. Curcumin also inhibites the expression of PSA and AR on LNCap cells.     

Analysis of different methylation patterns of histone H3 between androgen-dependent and androgen-independent prostate cancer cells by heavy methyl SILAC

AIM：To study the epigenetic mechanisms involved in the evolution of prostate cancer from an androgen-dependent state to an androgen-independent state, and the global difference of histone H3 methylation between androgen-dependent and -independent prostate cancer cells. METHODS：The methylation sites and patterns of histone H3 in androgen-dependent prostate cancer cell line LNCaP and androgen-independent prostate cancer cell line DU145 were analyzed by heavy methyl stable isotope labeling with amino acids in cell culture (SILAC) coupled with 2D LC-MS/MS. Western blotting was used to verify the results from MS. The differential expression of related methylases and demethylases was tested by real-time PCR. RESULTS：Five methylation sites on histone H3 were found in both cell lines, the patterns of which were as follows: H3K14me2, H3R17me1, H3K36me1, H3K36me2, H3K36me3, H3R72me2, H3K79me1 and H3K79me2. There were 2 different peptides both containing methylated H3K36, “KSAPATGGVKKPHR” and “KSAPSTGGVKKPHR”, which were different from the 31th amino acid residue “A” and “S”. The former peptide belonging to histone H3 variants, H31T, H31 and H32, was mainly identified in DU145 cells, the total peptide counts of which were much more than that of the latter peptide belonging to histone H3 variant H31T, suggesting that these 2 cell lines expressed different histone H3 variants. Mono- and dimethylation of H3K36 were not different between these 2 cell lines, but the trimethylation was significantly higher in DU145 cells than that in LNCaP cells. Many H3K36 demethyltransferases were decreased in DU145 cells compared with LNCaP cells. CONCLUSION：The differential expression of histone H3 variants and H3K36 demethyltransferases may result in up-regulation of H3K36 tri-methylation during the evolution of prostate cancer from an androgen-dependent state to an androgen-independent state.     

Effect of RelB on proteasome inhibitor-induced maspin expression

AIM: To investigate the effects of RelB on proteasome inhibitor-induced maspin expression in prostate cancer cells. METHODS: Western blotting analysis was performed to examine endogenous and proteasome inhibitor(MG-132)-induced expression of RelA, RelB and maspin in prostate cancer cells. The expression profiles of RelB and maspin in human prostate cancer tissues were obtained by immunohistochemistry assay. RNA interference targeting RelB was performed in DU145 cells. The effects of RelB-silencing on maspin expression induced by MG-132 were detected by Western blotting. The cell viability was determined by PI staining and FACS analysis. RESULTS: RelB expression was increased in androgen-independent prostate cancer cell line DU145, while maspin expression was minimally detected. Among 10 tissue samples tested, a strong nuclear RelB staining and an absence of maspin expression were found in high-grade specimens (Gleason scores 4-5). RelB expression was reduced upon treatment with MG-132 for 24 h, which was coincided with the induction of maspin expression. RelB-silencing in DU145 cells by siRNA didn't influence the proteasome inhibitor-induced maspin expression. CONCLUSION: The expression of RelB is inversely correlated to maspin expression in androgen-independent prostate cancer cells and prostate cancer tissues. RelB expression is critical to the proteasome inhibitor-induced maspin expression.     

Microarray analysis of tumor metastasis-related gene expression in PSMA-silencing prostate cancer cells

AIM: To investigate the functions of prostate-specific membrane antigen (PSMA) in prostate cancer metastasis. METHODS: Specific siRNA to knock down PSMA expression was designed and transfected into LNCaP cells. The tumor metastasis gene chip was also used to analyze the differential expression of 84 genes related to cancer metastasis. RESULTS: Specific siRNA was successfully designed and constructed and the gene expression of PSMA in LNCaP cells was knocked down. The RNAi efficiency was more than 75% at mRNA level and more than 68% at protein level. The results of the tumor metastasis gene chip indicated that 10 genes were up-regulated (such as CDH6 and CXCL12) and 4 genes were down-regulated (such as CCL7 and MDM2) in the LNCaP cells treated with PSMA siRNA. CONCLUSION: The PSMA is involved in the regulatory pathways in prostate cancer metastasis.     

Effect of prostate-specific membrane antigen on phospho-ERK,growth and migration of prostate cancer LNCaP cells

AIM: To study the expression of prostate-specific membrane antigen (PSMA) on the level of phospho-ERK, cell growth and migration of prostate cancer LNCaP cells.METHODS: The method of silencing PSMA was established by lentivirus-mediated RNAi in our early experiment. The cells were divided into 3 groups.In experimental group, the expression of PSMA in LNCaP cells was stably blocked by lentivirus-mediated RNAi. In negative control group, the cells were transfected with lentivirus-mediated control RNAi (without any interference to PSMA).The normal LNCaP cells served as blank control. The cells in these 3 groups were cultured in both 2 environments: normal medium and medium with PD98059 (an inhibitor of ERK phosphorylation). The phospho-ERK was detected by Western blotting and immunocytochemistry. Furthermore, the growth and migration of the cells were evaluated by MTT and transwell assays,respectively.RESULTS: In normal medium, the expression of phospho-ERK was attenuated in experimental group (P<0.05) and the quantity of "positive" cells was less than those in other 2 groups (P<0.05). Furthermore, the growth curves of the cells showed that the growth ability in experimental group was significantly decreased (P<0.05, after 48 h) and the migration ability in experimental group was reduced (P<0.05). In the inhibitory medium, the cells in all 3 groups expressed phospho-ERK at a lower level. Moreover, the abilities of growth and migration in these 3 groups were poorly displayed. These inhibitory effects on phosphorylation of ERK were similar to the cells in experimental group cultured in normal medium.CONCLUSION: PSMA may play a role in up-regulation of phospho-ERK and it may take an advantage in growth and migration of prostate cancer LNCaP cells.     

Role of ACSL3 expression in suppressing prostate cancer cell metastasis

AIM:To analyze the difference of long-chain acyl-CoA synthetase 3 (ACSL3) expression between normal prostate epithelial cells and prostate cancer cells.METHODS:ACLS3 mRNA expression between normal prostate epithelial cells and prostate cancer cells was compared using RT-PCR. Meanwhile, ACSL3 gene was amplified from prostate cancer cells, and the eukaryotic expression plasmid pCDNA3.1(+)-Flag-ACLS3 and lentivirus Lenti-ACLS3 were constructed. After transfection of ACSL3-plasmid and lentivirus into the prostate cancer cells, ACSL3 expressive was detected by RT-PCR and Western blotting, and then Matrigel invasion assay was performed to investigate the alteration of the invasive ability of the prostate cancer cells with over-expression of ACSL3. RESULTS:A significant difference of ACSL3 mRNA level between normal prostate epithelial cells and prostate cancer cells was observed. ACSL3 was highly expressed in localized prostate cancer cells compared to metastatic prostate cancer cells, while ACSL3 expression was higher in androgen-dependent prostate cancer cells than that in androgen-independent prostate cancer cells. Furthermore, the eukaryotic expression plasmid and lentivirus containing ACLS3 gene were successfully constructed. The prostate cancer cell line which stably over-expressed ACLS3 was established. Up-regulation of ACSL3 inhibited the invasive ability of prostate cancer cells. CONCLUSION:ACSL3 plays an antagonistic role in invasiveness of prostate cancer.     

Molecular mechanism of miR-29a inhibiting malignant phenotypes in prostate cancer cells

AIM:To investigate the biological functions of microRNA-29a (miR-29a) in prostate cancer and the molecular mechanism of miR-29a over-expression inhibiting malignant phenotypes of prostate cancer cells. METHODS:The levels of miR-29a expression in the prostate cancer tissues and cells were detected and analyzed using gene microarray and bioinformatics. The expression levels of miR-29a and lysine (K)-specific demethylase 4B (KDM4B) mRNA in prostate cancer tissues, paracarcinomatous tissues, 4 prostate cancer cell lines (PC3, DU145, LNCaP and ArCaP) and normal prostate epithelial cell line (RWPE-1) were measured by real-time PCR. PC3, DU145, LNCaP and ArCaP cells were transfected with pGenesil-1-miR-29a plasmid using transient transfection. The cell viability, colony formation rate and apoptotic rate were analyzed by MTT assay, colony formation assay and flow cytometry with Annexin V-FITC/PI staining, respectively. The protein expression of KDM4B was determined by Western blot. RESULTS:The results of gene microarray and bioinformatic analysis indicated that differential expression of miR-29a was found in the prostate cancer tissues and the paracarcinomatous tissues. The levels of miR-29a in the prostate cancer tissues and prostate cancer cells were significantly decreased, while the mRNA levels of KDM4B were notably increased compared with the paracarcinomatous tissues and RWPE-1 cells, respectively (P<0.05). Compared with negative control (pGenesil-1) group, the cell viability and colony formation rate were significantly decreased, the apoptotic rate was significantly increased, and the protein expression of KDM4B was notably inhibited in the prostate cancer cells with miR-29a over-expression (P<0.05). The cell viability was significantly enhanced, and the apoptosis was significantly inhibited in the prostate cancer cells with KDM4B over-expression (P<0.05). CONCLUSION:Low expression of miR-29a was found in the prostate cancer tissues and cells. miR-29a over-expression inhibits the growth of prostate cancer cells and induces apoptosis. The mechanism may be associated with inhibiting the protein expression of KDM4B.     

Osthole enhances doxorubicin-induced apoptosis in p53-wildtype prostate cancer cells by down-regulating SIRT1 expression

AIM: To investigate the effect and mechanism of osthole on increasing the cytotoxicity of doxorubicin (DOX) to prostate cancer cells. METHODS: MTT assay was performed to evaluate the viability of LNCaP cells treated with osthole and DOX. The protein expression of silent information regulator 1 (SIRT1), p53, acetylated p53 and Puma, as well as release of cytochrome C and activation of caspase-9 and caspase-3 in the LNCaP cells treated with osthole and DOX were determined by Western blot. The apoptosis of the LNCaP cells treated with osthole and DOX was analyzed by flow cytometry. RESULTS: Osthole significantly increased the cytotoxicity of DOX against p53-wildtype prostate cancer cell line LNCaP. Osthole significantly inhibited the expression of SIRT1 in the LNCaP cells. Transfection with SIRT1 plasmid decreased the cytotoxicity of osthole and DOX co-treatment against LNCaP cells. Combination with osthole and DOX significantly induced the over-expression and acetylation of p53. Transfection with p53 siRNA significantly decreased the synergistic effect of osthole on cytotoxicity of DOX-treated LNCaP cells. Combination with osthole and DOX significantly induced the release of cytochrome C into the cytoplasm from mitochondria, followed by activation of caspase-9 and its downstream molecule caspase-3, thus leading to cell apoptosis in the LNCaP cells. CONCLUSION: Osthole promotes the p53-dependent apoptosis in DOX-treated prostate cancer LNCaP cells by down-regulating the expression of SIRT1.     

Role of androgen receptor in prostate cancer cell proliferation by use of RNAi

AIM: To study the role of androgen receptor (AR) in hormone-dependent and hormone-independent prostate cancer cell proliferation by knocking down AR expression with adenovirus-delivered siRNA. METHODS: Four well-designed siRNAs were synthesized and inserted into the adenovirus plasmid pShuttle-H1-Ri. The recombinant pShuttle-H1-Ri-AR plasmid was then co-transfected with pcDNA-AR to HEK293 cell line and Western blot was used to detect the inhibitory efficiency of different siRNAs on AR expression. Recombinant adenovirus containing more efficient siRNAs were prepared and used to infect three different humane prostate cancer cell lines including LNCap、C4-2B and CWR22Rv1. The efficiency of knocking down AR expression was detected by Western blot. The effect of AR-knocking down on cell proliferation was detected by MTT colorimetric assay. RESULTS: All of the four designed siRNAs could knock down AR expression in transient co-transfection. Infecting with recombinant adenovirus containing more efficient siRNAs in hormone-dependent and hormone-independent prostate cancer cell lines specifically knocked down AR expression with high efficiency. Knocking down AR expression significantly decreased the proliferation rate in all these prostate cancer cells. CONCLUSION: The suppressed expression of AR in prostate cell lines mediated by siRNA could efficiently inhibit the cell proliferation, and these results show that AR plays an important role in the proliferation of hormone-dependent and hormone-independent prostate cancer cells. AR is an important therapeutic target for the treatment of prostate cancer.     

Juglone inhibits epithelial-mesenchymal transition of prostate cancer cells by regulating Wnt/β-catenin/Snail signaling pathway

AIM: To investigate the mechanism of juglone on epithelial-mesenchymal transition in prostate cancer cells. METHODS: Human prostate cancer LNCaP cells were divided into control group (without juglone), 12.5 μmol/L juglone group and 25 μmol/L juglone group. LNCaP cells in the latter 2 groups were treated with juglone for 24 h. The invasion ability of the LNCaP cells was detected by Transwell assay. The protein expression of E-cadherin, vimentin, Snail and β-catenin was determined by Western blot. The LNCaP cells were treated with LiCl and juglone in combination for 24 h, and the protein expression of Snail and E-cadherin was detected by Western blot.RESULTS: The results of Trans-well invasion assay showed that the invasion ability in juglone groups was significantly decreased (P<0.01). The protein expression of E-cadherin in the LNCaP cells treated with juglone was increased, and the expression levels of vimentin and β-catenin were reduced (P<0.01). Treatment with LiCl significantly attenuated the inhibitory effect of juglone on Snail expression and subsequent down-regulation of E-cadherin expression. CONCLUSION: Juglone inhibits the epithelial-mesenchymal transition by inhibiting the Wnt/β-catenin/Snail signaling pathway in the LNCaP cells.     

Effect of abnormal expression of PDK4 on glycolysis and proliferation in prostate cancer cells

AIM To investigate the expression of pyruvate dehydrogenase kinase 4 （PDK4） in prostate cancer tissue and its effect on glycolysis and growth of prostate cancer cells. METHODS Immunohistochemistry was used to compare the expression differences of PDK4 protein in benign prostatic hyperplasia （BPH） and prostate cancer tissues. The expression levels of PDK4 in normal prostatic epithelial cells （RWPE-1） and different prostate cancer cell lines （PC3, LNCaP, DU145 and C4-2） were detected by RT-qPCR and Western blot. Recombinant plasmid carrying PDK4-shRNA was constructed, and the expression of PDK4 in prostate cancer PC3 cells was down-regulated by transfection with PDK4-shRNA. The changes in glycolysis level of PC3 cells before and after transfection were determined by cell glycolysis kit, and the effects of PDK4 on the viability and cell cycle distribution of PC3 cells were detected by CCK-8 assay and flow cytometry. RESULTS In prostate cancer tissues, the expression level of PDK4 protein was significantly higher than that in BPH tissues （P<0.05）, and the analysis of immunohistochemical score showed that prostate cancer tissues with high Gleason score displayed significantly higher PDK4 expression than those with low Gleason score （P<0.05）. Compared with normal prostatic epithelial cells, RT-qPCR and Western blot results indicated that the expression level of PDK4 was also significantly increased in prostate cancer cell lines （P<0.05）. In addition, CCK-8 assay results showed that the viability of prostate cancer PC3 cells was significantly decreased after knockdown of PDK4 expression （P<0.05）. The results of flow cytometry demonstrated that knockdown of PDK4 expression in PC3 cells resulted in a notable increase in G₀/G₁ phase arrest （P<0.05）. CONCLUSION PDK4 is highly expressed in prostate cancer tissues and cell lines, and significantly increases in prostate cancer with high Gleason score. In addition, down-regulation of PDK4 expression significantly inhibits glycolysis and growth of prostate cancer cells, resulting in cell cycle arrest at G₀/G₁ phase.     

The effect of TNF-related apoptosis-inducing ligand on the activity of nuclear kappa B in prostate cancer cell line PC-3M

AIM: To investigate the activation and inactivation of nuclear factor kappa B (NF-κB) when tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is applied to induce the apoptosis of androgen-independent prostate cancer cell line PC-3M.METHODS: After the treatment of TRAIL or LPS at different doses, we tested the nuclear translocation of NF-κB by cell immunohistochemical staining and electrophoretic mobility shift assay(EMSA), and evaluated the level of IκB by RT-PCR under pyrrolidine dithiocarbamate (PDTC) treatment. RESULTS: EMSA and cell immunohistochemical analysis showed that the translocation of NF-κB was significantly activated when PC-3M cells were treated with TRAIL or LPS (P<0.05). The pretreatment of PDTC upregulated the expression of IκB and blocked the nuclear translocation of NF-κB.CONCLUSION: TRAIL remarkably stimulates the activation of nuclear NF-κB in androgen-independent prostate cancer cells. On the other hand, the translocation of NF-κB can be significantly and efficiently inhibited in PC-3M cells by pretreatment with PDTC. The increased expression of IκB might be a clue for this inhibition, which means the possible way to enhance the effect of TRAIL in the apoptosis of prostate cancer cells.     

Antiproliferation effects of 188Re labeled monoclonal antibody on prostate cancer cells in vitro

AIM: To investigate the effect of 188Re labeled monoclonal antibody on prostatic specific membrane antigen 7E11C5.3,radioimmunotherapy for the treatment of human prostate cancer cell line LNCaP in vitro.METHODS: 188Re-7E11C5.3 was prepared by direct 2-mercaptoethanol reduction method.Labeling efficiency and radiochemical purity was measured by paper chromatography.Immunoreactive fraction was determined by linear extrapolation.Cytotoxicity to LNCaP cells was determined by MTT assay.RESULTS: The labeling yield of 188Re-7E11C5.3 was (93.16±2.18)%,the radiochemical purity was (95.62±0.48)%,and the immunoreactive fraction was (74.86±1.86)%.The inhibitory effect of 188Re-7E11C5.3 on cell proliferation of LNCaP cells was significantly higher than that of 188Re-mIgG or 188ReO-4.The 50% inhibitory doses (IC50) of 188Re-7E11C5.3,188Re-mIgG,and 188ReO-4 were (23.38±3.73)×107 Bq/L,(59.21±8.02)×107 Bq/L and (68.89±10.91)×107 Bq/L,respectively.CONCLUSION: 188Re-7E11C5.3 can effectively inhibit the growth of in vitro cultured prostate cancer cells and shows much potential for prostate cancer radioimmunotherapy.     

Silencing of PSMA by RNAi influences biological behavior of prostate cancer cell line LNCaP

AIM: To study the blocking effect of shRNA on the expression of PSMA gene in LNCaP cell line by using shRNA eukaryotic expression vector. METHODS: Three pairs of DNA templates coding shRNA, synthesized against PSMA and cloned into the vector pSilencer 2.1-U6-neo, which was named pSilencer 2.1-U6-neo-shRNA, were identified by restriction endonuclease digestion analysis and DNA sequencing. LNCaP cells were then transfected with these three pSilencer 2.1-U6-neo-shRNAs and the negative control pSilencer 2.1-U6-neo-NC. After G418 selection, the cells were selected and the interfering effect was detected by RT-PCR and Western blotting. The biological behaviours of the transfected LNCaP cells were also tested. RESULTS: Restriction endonuclease digestion analysis and DNA sequencing results all showed that the 3 target segments were cloned into pSilencer 2.1-U6- neo vector respectively. After transfected into LNCaP cells, the inhibitory ratio of PSMA mRNA was 33.15%, 9.26% and 41.97% respectively, and that of PSMA protein was 26.26%, 6.47%, 40.69% respectively. The p-shRNA3 was chosen to test the cell growth and its invasive power in vitro. The results showed that after interfering, the invasiveness of LNCaP cells were enhanced. CONCLUSION: The vector-based shRNA on PSMA gene effectively knocks down the PSMA gene expression. The successful construction of PSMA shRNA makes it possible for further study of the interaction between PSMA and prostate cancer.     

Apoptosis of the prostate cancer cell line PC-3M induced by E2F decoy DNA

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.