Feng Kong

Shandong University, Jinan, Shandong Sheng, China

Are you Feng Kong?

Claim your profile

Publications (20)44.56 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We recently reported that Riccardin D (RD) was able to induce apoptosis by targeting Topo II. Here, we found that RD induced cell cycle arrest in G2/M phase in PC-3 cells, and caused remarkable DNA damage as evidenced by induction of γH2AX foci, micronuclei, and DNA fragmentation in Comet assay. Time kinetic and dose-dependent studies showed that ATM/Chk2 and ATR/Chk1 signaling pathways were sequentially activated in response to RD. Blockage of ATM/ATR signaling led to the attenuation of RD-induced γH2AX, and to the partial recovery of cell proliferation. Furthermore, RD exposure resulted in the inactivation of BRCA1, suppression of HR and NHEJ repair activity, and downregulation of the expressions and DNA-end binding activities of Ku70/86. Consistent with the observations, microarray data displayed that RD triggered the changes in genes responsible for cell proliferation, cell cycle, DNA damage and repair, and apoptosis. Administration of RD to xenograft mice reduced tumor growth, and coordinately caused alterations in the expression of genes involved in DNA damage and repair, along with cell apoptosis. Thus, this finding identified a novel mechanism by which RD affects DNA repair and acts as a DNA damage agent in prostate cancer.
    PLoS ONE 01/2013; 8(9):e74387. · 3.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To examine whether two naturally occurring sesquiterpenoids (ST1 and ST2) with anti-proliferative activity in prostate cancer cells inhibit androgen receptor (AR) signaling. Human prostate cancer cell lines LNCaP and PC3 were used. The expression of AR, AR translocation into the nucleus, and expression levels of AR coactivators ARA70 and steroid receptor coactivator-1 (SRC-1) in LNCaP cells were examined using real-time PCR and Western blot. Changes in prostate-specific antigen (PSA) protein levels, PSA promoter activity, and androgen response element (ARE)-mediated reporter gene activity were examined using enzyme-linked immunoabsorbent assay (ELISA) and transient transfection assays. Co-immunoprecipitation was performed to analyze the interaction between AR and the AR coactivators in ST1- and ST2-treated cells. In LNCaP cells, ST1 and ST2 (40 μmol/L) led to a significant decrease in the expression of AR as well as a reduction of AR translocation into the nucleus, but had no effect on AR protein translation. ST1 and ST2 treatment also resulted in a significant decrease in the level of PSA protein secreted into the medium and was able to suppress PSA promoter-dependent and ARE-dependent luciferase activity. Furthermore, decreased expression of ARA70 and SRC-1 was observed when LNCaP cells were exposed to ST1 and ST2, which interfered with their ability to interact with AR. The observations suggest that suppression of AR transactivation by ST1 and ST2 may be mediated, in part, by inhibiting AR nuclear translocation and/or interfering with the interaction between AR and its coactivators ARA70 and SRC-1. Therefore, sesquiterpenoids could be developed as novel therapeutic agents for treating prostate cancer.
    Acta Pharmacologica Sinica 03/2011; 32(3):338-44. · 2.35 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: P-glycoprotein (P-gp) is known to mediate multidrug resistance (MDR) by acting as an efflux pump to actively transport chemotherapeutic agents out of carcinoma cells. Inhibition of P-gp function may represent one of the strategies to reverse MDR. We have previously reported that marchantin C (MC), a macrocyclic bisbibenzyl compound from liverworts, exerts anti-tumor activity as an antimitotic agent. This study was designed to evaluate the possible modulatory effect of MC and its three synthetic derivatives (MC1, MC2 and MC3) on P-gp in VCR-resistant KB/VCR cells. Results of the cytotoxicity assay revealed that MC was the most potent inhibitor of cell proliferation in both KB and KB/VCR cells among these four compounds, while the three MC-derived chemicals had little anti-proliferative activity under the same condition. However, in P-gp-expressing MDR cells, analysis of potency of these compounds in enhancing cytotoxicity of VCR led to the identification of MC2 as a more effective chemical on reversal of resistance. Further study showed that MC2 was able to reduce efflux of rhodamine-123, and in turn, increase the accumulation of rhodamine-123 and adriamycin in KB/VCR cells, indicating that MC2 re-sensitized cells to VCR by inhibition of the P-gp transport activity. In addition, the combination of MC2 and VCR at a concentration that does not inhibit cell growth resulted in an induction of apoptosis in KB/VCR cells. These results suggest that MC2, as a novel and effective inhibitor of P-gp, may find potential application as an adjunctive agent with conventional chemotherapeutic drugs to reverse MDR in P-gp overexpressing cancer cells.
    Bioorganic & medicinal chemistry 09/2010; 18(18):6725-33. · 2.82 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: It has been hypothesized that the accumulation of beta-amyloid peptide (Abeta) in the brain is a triggering event leading to the pathological cascade of Alzheimer's disease. The steady-state levels of Abeta are determined by the metabolic balance between anabolic and catabolic activity and the dysregulation of this activity leads to Alzheimer's disease. Recent evidence has shown that neprilysin (NEP) is the rate-limiting enzyme in the Abeta degradation in the brain. Ginseng, the root of Panax ginseng C.A. Meyer, is widely used as a tonic for the prevention and treatment of age-related disorders in China. We aimed to investigate the basis of this use. In this study, we investigated the effect of ginsenoside Rg3, one of the major active components of ginseng, on the metabolism of Abeta40 and Abeta42 in SK-N-SH cells transfected with Swedish mutant beta-amyloid precursor protein (SweAPP). The ELISA result showed that Rg3 significantly reduced the levels of Abeta40 and Abeta42, 19.65 +/- 6.05%, 23.61 +/- 6.74%, respectively (P < 0.01). The Western blot analysis showed that Rg3 reduced the levels of Abeta40 and Abeta42 through enhancing NEP gene expression, and real-time PCR assay showed that 50 microM Rg3 could significantly enhance NEP gene expression (2.9 fold at 48 h). Our findings suggest that the Rg3 compound of ginseng may be useful for treating patients suffering with Alzheimer's disease.
    Journal of Pharmacy and Pharmacology 03/2009; 61(3):375-80. · 2.03 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To investigate the effect of ginsenosides Rb1 and Rg1 on Neprilysin (NEP) activity in SK-N-SH cells, and probe the underlying mechanism. The effects of ginsenosides Rb1 and Rg1 on NEP activity were analyzed by NEP peptidase assay. Western blot was used to determine NEP gene expression at translational level, and RT-PCR was also performed to detect NEP gene expression at transcriptional level. NEP peptidase assay indicated that ginsenoside Rb1 can improve the activity of NEP, and RT-PCR and western blot results showed that the enhancement of NEP activity by ginsenoside Rb1 was due to enhancing NEP gene expression, while Rg1 did not have this effect. Our studies showed that ginsenoside Rb1 can enhance NEP activity by upregulating NEP gene expression. Our findings might offer a pharmacological explanation for the use of ginseng in traditional medicine.
    Neuro endocrinology letters 01/2009; 29(6):924-8. · 0.93 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Photodynamic therapy (PDT) is a promising treatment on neoplastic pathologic tissues, which involves the administration of a photosensitizing agent followed by exposure of the tissue to visible non-thermal light. In our previous findings MPPa was showed to be a good photosensitizer candidature, because it can lead PC-3M cell line to death mainly via apoptotic way. In this study, we studied the effect of overexpression of hypoxia inducible factor-1α (HIF-1α) on MPPa-PDT. Over expression of HIF-1α was induced by cobalt chloride (CoCl2) and then the cell viability was tested by MTT assay. After that, HIF-1α siRNA was transfected into PC-3M cells to knock down the expression of HIF-1α and the cell viability was observed. Western blot was used to determine the expression of HIF-1α. Finally, we found that the over expression of HIF-1α would reduce the photodynamic effect of MPPa on PC-3M cells, while the photodynamic effect would be enhanced by HIF-1α siRNA. (© 2008 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)
    Laser Physics Letters 09/2008; 5(10):764 - 767. · 7.71 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Androgen receptor (AR)-mediated signaling is crucial for the development and progression of prostate cancer (PCa). Naturally occurring phytochemicals that target the AR signaling offer significant protection against this disease. Acetyl-11-keto-beta-boswellic acid (AKBA), a compound isolated from the gum-resin of Boswellia carterii, caused G1-phase cell cycle arrest with an induction of p21(WAF1/CIP1), and a reduction of cyclin D1 as well in prostate cancer cells. AKBA-mediated cellular proliferation inhibition was associated with a decrease of AR expression at mRNA and protein levels. Furthermore, the functional biomarkers used in evaluation of AR transactivity showed suppressions of prostate-specific antigen promoter-dependent and androgen responsive element-dependent luciferase activities. Additionally, down-regulation of an AR short promoter mainly containing a Sp1 binding site suggested the essential role of Sp1 for the reduction of AR expression in cells exposed to AKBA. Interruption effect of AKBA on Sp1 binding activity but not Sp1 protein levels was further confirmed by EMSA and transient transfection with a luciferase reporter driven by three copies of the Sp1 binding site of the AR promoter. Therefore, anti-AR properties ascribed to AKBA suggested that AKBA-containing drugs could be used for the development of novel therapeutic chemicals.
    Biochemical pharmacology 07/2008; 75(11):2112-21. · 4.25 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: NKX3.1 and PCAN1 are both prostate-specific genes related to prostate development and prostate cancer. So far, little is known about the regulatory mechanisms of the expression of these two genes. In the present study, we found that NKX3.1 upregulated PCAN1 gene transcription in LNCaP prostate cancer cells. To understand the regulatory mechanisms, our work focused on identifying the functional NKX3.1 binding sites upstream of the PCAN1 gene, which might be involved in the positive regulation of PCAN1 expression by NKX3.1. We cloned and characterized a 2.6 kb fragment upstream of the PCAN1 gene. Analysis of the 2.6 kb sequence with MatInspector 2.2 revealed five potential binding sites of NKX3.1 transcription factor. Luciferase reporter assays, electrophoretic mobility shift assays, chromatin immunoprecipitation and RNA interference were performed to study the effects of NKX3.1 on PCAN1 gene expression in prostate cancer cells. Our results showed that PCAN1 promoter activity and mRNA expression were increased by transfection with the NKX3.1 containing plasmid (pcDNA3.1-NKX3.1) and that PCAN1 mRNA expression was decreased by RNA interference targeting human NKX3.1 in LNCaP prostate cancer cells. The results of electrophoretic mobility shift assays and chromatin immunoprecipitation showed that NKX3.1 bound to NBS1 (-1848 to -1836) and NBS3 (-803 to -791) upstream of the PCAN1 gene. The luciferase reporter assays showed that NBS1 and NBS3 enhanced the promoter activity in pGL3-promoter vector with cotransfection of the NKX3.1 containing plasmid. Furthermore, the deletion of NBS1 or both NBS1 and NBS3 reduced PCAN1 promoter activity and abolished the positive regulation of PCAN1 expression by NKX3.1. Our results suggested that two functional NKX3.1 binding sites located at -1848 to -1836 and -803 to -791 upstream of the PCAN1 gene were involved in the positive regulation of PCAN1 gene transcription by NKX3.1.
    BMC Molecular Biology 02/2008; 9:45. · 2.80 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To identify the effect of NEP on Abeta -induced apoptosis in PC12 cells. PC12 cells that stably express NEP is generated and the effect of NEP on the process of apoptosis induced by Abeta is analyzed, including the viability of the cells, the production of LDH, ROS and ATP, the activity of Caspase-3. NEP could improve the viability of cells and the production of ATP, inhibit the release of LDH and ROS. In the same time, the activity of caspase-3 descended (P < 0.05). But iNEP had not significant effect on cells apoptosis (P > 0.05). NEP has the protective effect on Abeta-induced apoptosis in PC12 cells.
    Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases 01/2008; 25(12):722-5.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Zinc is essential for cell growth and is a co-factor for more than 300 enzymes, representing over 50 different enzyme classes. Two gene families have been identified involved in zinc homeostasis. ZnT transporters reduce intracellular zinc while ZIP transporters increase intracellular zinc. Previous studies have shown that zinc concentration in breast cancer tissues is higher than that in normal breast tissues. However, the mechanisms involved and the relations to zinc transporters are still unknown. A series of zinc transporters are characterized in this article and several of that are emphasized in view of their unique tissue-specific expressions. Established human breast cancer in a nude mice model is used. With a dietary zinc supplement treatment, ZnT-1 mRNA expression in established human breast cancer is raised by 24%, and is nearly 2 times of that in basal diet. ZIP1, ZIP2 and LIV-1 mRNA are the same between two treatment groups. Moreover, no significant changes of these zinc transporters expressions are found between differential breast cancer cell lines in the nude mice model. This is the first report, which detects the zinc transporters expressions in established human breast cancer in nude mice model. These results lead to the constitutive expression and response to zinc in different tissues. In addition to that, ZnT-1 seems to have played an important role in zinc homeostasis, even in breast cancer.
    Molecular Biology Reports 01/2008; 34(4):241-7. · 2.51 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To determine the effects of the functional domain of saposin C (neurotrophic peptide [NP]) on androgen receptor (AR) expression and transcriptional activity. We constructed DNA vectors expressing NP or a chimeric peptide of the viral TAT transduction domain and NP (TAT-NP) using gene cloning technology. The effects of ectopic expression of NP or TAT-NP on cell growth were examined by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Reverse transcription-polymerase chain reaction (RT-PCR), Western blot, transient transfection and reporter gene assays were used to determine the effects of NP on AR expression and activation. NP stimulated proliferation of androgen responsive LNCaP cells in the absence of androgens. RT-PCR and Western blot analyses showed that ectopic expression of NP resulted in induction of AR gene expression, and that the NP-stimulated expression of AR could be synergistically enhanced in the presence of androgens. Furthermore, reporter gene assay results showed that NP could enhance AR transactivation by increasing androgen-inducible gene reporter activity. We provided evidence that ectopic expression of saposin C-originated NP could upregulate AR gene expression and activate the AR transcriptional function in an androgen-independent manner in prostate cancer cells.
    Asian Journal of Andrology 10/2007; 9(5):601-9. · 2.14 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Zinc is essential for cell growth. Previous studies have shown that zinc concentration in breast cancer tissues is higher than that in normal breast tissues. Zinc cannot passively diffuse across cell membranes and specific zinc transporter proteins are required. Two gene families have been identified involved in zinc homeostasis. ZnT transporters reduce intracellular zinc while ZIP transporters increase intracellular zinc. In this study, three human zinc transporter members: ZnT-1, ZIP2 and LIV-1 were chosen. We aimed to determine the effect of flaxseed lignan on the growth of ER-negative breast cancer cells in a nude mice model and observe the effect of flaxseed lignan on the regulation of the three zinc transporter in mRNA level. Nude mice were xenografted with human breast cancer cell line MDA-MB-231 and 6 weeks later were fed either the basal diet (BD) or BD supplemented with 10% FS and SDG for 5 weeks. The SDG levels were equivalent to the amounts in the 10% FS. RT-PCR was performed. Compared with the BD group, the tumor growth rate was significantly lower (P < 0. 05) in the FS and SDG group. ZnT-1 mRNA level in mammary tumor was increased in SDG group and decreased in FS group, but no significant difference was found. Extremely low amplification of ZIP2 from mRNA was detected, with no difference between the treatment groups. LIV-1 mRNA expression of SDG group increases compared with BD group. In FS group, it significantly increases nearly 9 times than that in BD group (P < 0. 005).
    Molecular Biology Reports 09/2007; 35(4):595-600. · 2.51 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A cycloartane-type triterpenoid (1), an aliphatic alcohol glycoside (2), an eudesmane-type sesquiterpenoid (3), and a guaiane-type sesquiterpenoid (4) were isolated from the resinous exudates of Commiphora opobalsamum along with six known sesquiterpenoids (5-10). Their structures were established by extensive analysis of their 1D and 2D NMR spectroscopic data and chemical methods. The isolated compounds 1-3 and 5-9 were tested against human prostate cancer cell PC 3 and LNCaP. Among them, 1 and 2 showed moderate antiproliferative effects on human prostate cancer cell lines with IC50 values ranging from 5.7 to 23.6 microM; they were also able to inhibit the expression of androgen receptor (AR) in LNCaP cells. The six sesquiterpenoids were inactive in the bioassays.
    Phytochemistry 06/2007; 68(9):1331-7. · 3.05 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To elucidate the effect and the mechanisms of curcumin on the expression of the human homeobox gene NKX3.1 in the prostate cancer cell LNCaP. The expression change of NKX3.1 in cells incubated with varying concentrations of curcumin was observed by Western blotting and RT-PCR. A dual luciferase reporter assay was used to test the effect of curcumin on the activity of the NKX3.1 1040 bp promoter. Curcumin-treated cells disposed to a designated amount of androgen analog R1881 and the androgen receptor (AR) antagonist flutamide, then the expression of NKX3.1 or the activity of the NKX3.1 promoter were investigated by Western blotting or reporter gene assay, respectively. Finally, Western blotting and electrophoretic mobility shift assay were performed to demonstrate the effect of curcumin on the expression of AR and its binding activity to the androgen response element (ARE). Curcumin downregulated the expression of NKX3.1 and the activity of the NKX3.1 1040 bp promoter in LNCaP cells. R1881 increased the expression of NKX3.1, and the AR antagonist flutamide decreased the expression of NKX3.1 in LNCaP cells, while curcumin could inhibit androgen-AR mediated induction of NKX3.1 expression. Curcumin decreased the expression of AR and the binding activity to ARE directly. Curcumin could downregulate NKX3.1 expression in LNCaP cells. It could also inhibit the androgen-AR mediated induction of NKX3.1 expression by downregulating AR expression and blocking its DNA binding activity.
    Acta Pharmacologica Sinica 04/2007; 28(3):423-30. · 2.35 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Human PCAN1 (prostate cancer gene 1) is a prostate-specific gene that is highly expressed in prostate epithelial tissue, and frequently mutated in prostate tumors. To better understand the regulation of the PCAN1 gene, a 2.6-kb fragment of its 5' flanking region was obtained by PCR. Its promoter activity was examined via the dual-luciferase reporter assay after it had been cloned into a pGL(3)-basic vector generating pGL(3)-p2.6 kb and transfected into LNCaP cells. pGL(3)-basic and pGL(3)-control were respectively used as the negative and positive controls. Sequence analysis with the MatInspector database showed that some possible binding sites for the transcriptional factors, NKX3.1, P53, SP1, cEBP and the PPAR/RXR heterodimers may locate on a 2.6-kb region upstream of the PCAN1 gene. To examine the relevant regulation of PCAN1, pGL(3)-p2.6 kb was transfected into the prostate cancer cell line LNCaP, which was treated with R1881 (10(-7) approximately 10(-9) mol/l), 17beta-estradiol (17beta-E(2), 10(-7) approximately 10(-9) mol/l), all-trans-retinoic acid (all-trans-RA, 10(-5) approximately 10(-7) mol/l) or 9-cis-retinoic acid (9-cis-RA, 10(-5) approximately 10(-7) mol/l), and eukaryotic expression plasmids of NKX3.1, p53, Sp1, Pten, PPARgamma or cEBPalpha were cotransfected with pGL(3)-p2.6 kb into LNCaP cells. pRL-TK, a Renilla luciferase reporter vector, was cotransfected into all the transfection lines as an internal control. The activities of pGL(3)-p2.6 kb (PCAN1 promoter) were analyzed via the dual-luciferase reporter assay 48 h after transfection. The results showed that 9-cis-RA enhanced the PCAN1 promoter activity in a dose-dependent manner, while R1881, 17beta-E(2) and all-trans-RA had no significant effect on PCAN1 promoter activities. Cotransfection with pGL(3)-p2.6kb and the expression plasmids of NKX3.1, p53, Sp1 or Pten respectively resulted in 1.66-, 2.48-, 2.00-and 1.72-fold 2.6 kb PCAN1 promoter activity increases relative to the controls, which were cotransfected with pcDNA3.1(+), while cotransfection of PPARgamma and cEBPalpha yielded no significant effect on PCAN1 promoter activities. These results could be applied for further study of the function and transcription regulation of the PCAN1 gene in prostate development and carcinogenesis.
    Cellular & Molecular Biology Letters 02/2007; 12(4):482-92. · 1.95 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To further uncover the possible mechanism of quercetin-mediated inhibitory effect on prostate cancer cells. The cell extracts treated with quercetin or without treatment were used for checking protein expression levels of c-Jun and cAMP response element binding protein (CREB)-binding protein (CBP) by Western blotting assay. Regulatory effects of c-Jun and CBP on the function of androgen receptor (AR) were examined by cotransfection experiment. Finally, a physical interaction of c-Jun and the AR was investigated by coimmunoprecipitation. Quercetin dramatically induced the protein expression of c-Jun which in turn inhibited the AR function. Meanwhile, quercetin had no detectable effect on CBP expression, and the results of transient transfection demonstrated that the ectopic CBP stimulated the transcriptional activity of AR, whereas CBP-mediated stimulation could be attenuated by quercetin. Furthermore, physical interaction of c-Jun and the AR was confirmed by coimmunoprecipitation result. Overexpression of c-Jun induced by quercetin had inhibitory effect on the function of AR protein, and increased CBP expression did not reverse the inhibition by quercetin. Together, quercetin-mediated inhibition on the AR function might be not by competition with limited amount of CBP in the cell, but through a direct association of c-Jun and the AR.
    Yao xue xue bao = Acta pharmaceutica Sinica 10/2006; 41(9):819-24.
  • [Show abstract] [Hide abstract]
    ABSTRACT: To explore the mechanism of reactive oxygen species (ROS) in manganese chloride (MnCl(2))-induced apoptosis in PC12 cells. The model that MnCl(2) induced apoptosis in PC12 cells was established. The apoptotic effect of MnCl(2) on PC12 cells was analyzed with the MTT, the flow cytometry and the DNA fragmentation. The production of ROS and ATP in MnCl(2)-induced apoptosis of PC12 cells was examined. The influence of MnCl(2) on the expression of bcl-xl, bax and the activity of Caspase 3 was also analyzed. MnCl(2) triggered PC12 cells apoptosis in a dose-and time-dependent manner (P < 0.01). The rate of apoptosis was significantly increased (P < 0.01) when MnCl(2) of 2 mmol/L induced PC12 cells for 36 hours. The production of ROS was increased (P < 0.001) and the quantity of ATP was decreased (P < 0.01) in PC12 cells with the same inducement of MnCl(2). The expression of bcl-xl was inhibited and the bax was activated in this process (P < 0.01). Caspase 3 was also activated (P < 0.01). MnCl(2) induces apoptosis of PC12 cells, which is related to the increase of ROS, the inhibition of the mitochondria and the activation of Caspase 3.
    Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases 03/2006; 24(3):157-60.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: NKX3.1 is a prostate-specific homeobox gene related to prostate development and prostate cancer. In this work, we aimed to identify precisely the functional cis-element in the 197 bp region (from -1032 to -836 bp) of the NKX3.1 promoter (from -1032 to +8 bp), which was previously identified to present positive regulatory activity on NKX3.1 expression, by deletion mutagenesis analysis and electrophoretic mobility shift assay (EMSA). A 16 bp positive cis-element located between -920 and -905 bp upstream of the NKX3.1 gene was identified by deletion mutation analysis and proved to be a functional positive cis-element by EMSA. It will be important to further study the functions and regulatory mechanisms of this positive cis-element in NKX3.1 gene expression.
    Acta Biochimica et Biophysica Sinica 12/2005; 37(11):773-8. · 1.81 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To study the effect of curcumin on the expression of prostate specific antigen (PSA). AXSYM system-chemical luciferase method was used to examine the content of PSA in prostate cancer cell lines, LNCap after treated with different doses of curcumin. pGL3-PSA luciferase expression vector, containing 640 bp DNA of PSA gene 5' promoter region was constructed and transfected into LNCap cell with lipofectin. Through detecting the activity of luciferase, the effect of curcumin on the promoter of PSA was studied. Western blotting was used to detect expression of androgen receptor (AR) in LNCap cell with different concentrations of curcumin. The expression of PSA was inhibited and activity of luciferase was reduced by curcumin. There was also significant difference in AR expression as shown by Western blotting experiment after treatment of different doses of curcumin. Through inhibiting AR expression, curcumin reduced the function of PSA promoter and inhibited PSA protein expression.
    Yao xue xue bao = Acta pharmaceutica Sinica 10/2005; 40(9):800-3.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: NKX3.1 is an androgen-regulated prostate-specific homeobox gene that is thought to play an important role in prostate development and cancerogenesis. NKX3.1 acts as a tumor suppressor gene specifically in the prostate. Up-regulation of NKX3.1 gene offers a promising gene therapy for prostate cancer. The decoy strategy has been developed and is considered a useful tool for regulating gene expression and gene therapy. In our previous studies, we identified a 20 bp inhibitory element upstream of the NKX3.1 promoter. In this study, we focused on using the 20 bp inhibitory element decoy to block negative regulation of the NKX3.1 gene and to up-regulate NKX3.1 expression using synthetic double-stranded oligodeoxynucleotides of the 20 bp inhibitory element. We found in an electrophoretic mobility shift assay experiment that the 20 bp inhibitory decoy presented competitive binding to a specific binding protein of the 20 bp inhibitory element in prostate cancer cell line LNCaP. In luciferase reporter gene assays, we found that the 20 bp inhibitory decoy could enhance NKX3.1 promoter activity, and RT-PCR and Western blot analysis revealed that NKX3.1 expression was up-regulated effectively by the transfection with the 20 bp inhibitory decoy. Furthermore, cell proliferation was inhibited by up-regulated NKX3.1 expression induced by the 20 bp inhibitory decoy.
    Acta Biochimica et Biophysica Sinica 06/2005; 37(5):335-40. · 1.81 Impact Factor