ObjectiveTo explore the expression of pituitary tumor transforming gene 1 (PTTG1) during the transformation of prostate cancer from androgen-dependent (ADPC) to androgen-independent (AIPC).

METHODSWe established an AIPC cell model LNCaP-AI by culturing the androgen-dependent LNCaP cell line in the hormone-deprived medium for over 3 months. The cell model was verified and the PTTG1 expression in the LNCaP cells was detected by Western blot and RT-PCR during hormone deprivation.

RESULTSThe AIPC cell model LNCaP-AI was successfully established. The PTTG1 expression was gradually increased in the LNCaP cells with the prolonged time of hormone deprivation and the expressions of matrix metalloproteinases MMP-2 and -9 were elevated at the same time.

CONCLUSIONSThe expression of PTTG1 is increased gradually in AIPC, which may be a target of gene therapy for advanced prostate cancer.

Blotting, Western ; Cell Line, Tumor ; Gene Expression Regulation, Neoplastic ; Humans ; Male ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Neoplasms, Hormone-Dependent ; Prostatic Neoplasms ; enzymology ; genetics ; Securin ; genetics

AIMTo investigate the mechanism of androgen-independent growth of prostate cancer after androgen ablation in LNCaP cells and the effect of glucuronidation activity.

METHODSTo establish androgen-independent growth in prostate cancer LNCaP-SF, continuous passage was performed in androgen-stripped medium and the cells were evaluated for glucuronidation activity. The expression vector of antisense uridine diphosphate glucuronosyl-transferase (UGT) 2B15 cDNA was also constructed and evaluated.

RESULTSLNCaP-SF lead to a higher expression in UGT2B15 and their glucuronidation activity is 2.5 times higher than that of LNCaP cells. Significantly fewer LNCaP and LNCaP-SF than control were transfected with the antisense UGT2B15 cDNA, suggesting that UGT2B15 plays an important part in the glucuronidation activity of androgens in both cells.

CONCLUSIONThe alteration of UGT2B15 expression in LNCaP-SF cells is proposed as a biological characteristic involved in the growth of hormone-refractory prostate cancer.

Androgens ; metabolism ; Cell Division ; physiology ; DNA, Antisense ; Glucuronic Acid ; metabolism ; Glucuronosyltransferase ; genetics ; metabolism ; Humans ; Male ; Prostatic Neoplasms ; Transfection ; Tumor Cells, Cultured ; cytology ; enzymology

BACKGROUNDProstate specific membrane antigen (PSMA) can facilitate the growth, migration, and invasion of the LNCaP prostate cancer cell lines, but the underlying molecular mechanisms have not yet been clearly defined. Here, we investigated whether PSMA serves as a novel regulator of the phosphatidylinositol 3-kinase (PI3K)/Akt signaling by employing PSMA knockdown model and PI3K pharmacological inhibitor (LY294002) in LNCaP prostate cancer cells.

METHODSPSMA knockdown had been stably established by transfecting with lentivirus-mediated siRNA in our previous study. Then, LNCaP cells were divided into interference, non-interference, and blank groups. We first testified the efficacy of PSMA knockdown in our LNCaP cell line. Then, we compared the expression of PSMA and total/activated Akt by Western blotting in the above three groups with or without LY294002 treatment. Furthermore, immunocytochemistry was performed to confirm the changes of activated Akt (p-Akt, Ser473) in groups. Besides, cell proliferation, migration, and cell cycle were measured by CCK-8 assay, Transwell analysis, and Flow cytometry respectively.

RESULTSAfter PSMA knockdown, the level of p-Akt (Ser473) but not of total-Akt (Akt1/2) was significantly decreased when compared with the non-interference and blank groups. However, LY294002 administration significantly reduced the expression of p-Akt (Ser473) in all the three groups. The results of immunocytochemistry further confirmed that PSMA knockdown or LY294002 treatment was associated with p-Akt (Ser473) down-regulation. Decrease of cell proliferation, migration, and survival were also observed upon PSMA knockdown and LY294002 treatment.

CONCLUSIONSTaken together, our results reveal that PI3K/Akt signaling pathway inhibition may serve as a novel molecular mechanism in LNCaP prostate cancer cells of PSMA knockdown and suggest that Akt (Ser473) may play a critical role as a downstream signaling target effector of PSMA in this cellular model.

Antigens, Surface ; genetics ; metabolism ; Cell Line, Tumor ; Glutamate Carboxypeptidase II ; genetics ; metabolism ; Humans ; Male ; Phosphatidylinositol 3-Kinases ; metabolism ; Prostatic Neoplasms ; enzymology ; genetics ; therapy ; Proto-Oncogene Proteins c-akt ; metabolism ; RNA Interference ; Signal Transduction ; genetics ; physiology

Reactive oxygen species (ROS) are involved in a diversity of important phenomena in the process of tumor development. To investigate the alterations of oxidative stress and their related systems in tumor progression, a variety of components in the antioxidative stress defense system were examined in prostate cancer cell lines, PC3 and LNCaP. Cell surface molecules involved in metastasis were expressed highly in PC3 cells compared with LNCaP cells, and strong invasion ability was shown in PC3 cells only. ROS level in LNCaP cells was twice higher than that in PC3 cells, although nitric oxide (NO) level was similar between the two cell lines. The content of GSH increased up to about 2-fold in PC3 compared with LNCaP. Activities of glutathione reductase, thioredoxin reductase, and glutathione S-transferase except catalase are significantly higher in PC3 cells than in LNCaP cells. Furthermore, oxidative stress-inducing agents caused down-regulation of GSH and glutathione S-transferase much more significantly in LNCaP cells than in PC3 cells. These results imply that malignant tumor cells may maintain low ROS content by preserving relatively high anti-oxidative capacity, even in the presence of stressful agents.
Antioxidants/metabolism ; Cell Line, Tumor ; Enzyme Induction ; Gene Expression Regulation, Neoplastic ; Humans ; Male ; *Oxidative Stress ; Prostatic Neoplasms/enzymology/*genetics/*metabolism ; Reactive Oxygen Species/*metabolism ; Research Support, Non-U.S. Gov't ; Thioredoxin Reductase (NADPH)/metabolism ; Up-Regulation/*genetics

Metastasis represents by far the most feared complication of prostate carcinoma and is the main cause of death for patients. The skeleton is frequently targeted by disseminated cancer cells and represents the sole site of spread in more than 80% of prostate cancer cases. Compatibility between select malignant phenotypes and the microenvironment of colonized tissues is broadly recognized as the culprit for the organ-tropism of cancer cells. Here, we review our recent studies showing that the expression of platelet-derived growth factor receptor alpha (PDGFRα) supports the survival and growth of prostate cancer cells in the skeleton and that the soluble fraction of bone marrow activates PDGFRα in a ligand-independent fashion. Finally, we offer pre-clinical evidence that this receptor is a viable target for therapy.
Animals ; Antibodies, Monoclonal ; therapeutic use ; Bone Marrow ; enzymology ; pathology ; Bone Neoplasms ; prevention & control ; secondary ; Enzyme Activation ; Humans ; Male ; Prostatic Neoplasms ; drug therapy ; enzymology ; pathology ; Receptor, Platelet-Derived Growth Factor alpha ; antagonists & inhibitors ; genetics ; immunology ; metabolism ; Signal Transduction ; Transcriptional Activation

OBJECTIVETo investigate the inhibiting effect of telomerase with hTERT antisense on TNF-alpha-induced apoptosis in prostate cancer cells PC3.

METHODSAntisense phosphorothioate oligodeoxynucleotide (AS PS-ODN) was synthesized and purified. Telomerase activity was measured by telomeric repeat amplification protocol (TRAP) and telomerase PCR-ELISA Kit, cell viability was determined by MTT assay, and cell apoptosis was observed by morphological method and determined by flow cytometry.

RESULTSAS PS-ODN could significantly inhibit the telomerase activity and increase the susceptibility of TNF-alpha-induced apoptosis of PC3 cells.

CONCLUSIONInhibition of telomerase with hTERT antisense can enhance TNF-alpha-induced apoptosis in prostate cancer cells.

Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Survival ; drug effects ; Enzyme-Linked Immunosorbent Assay ; Humans ; Male ; Oligodeoxyribonucleotides, Antisense ; genetics ; pharmacology ; Polymerase Chain Reaction ; Prostatic Neoplasms ; enzymology ; genetics ; pathology ; Telomerase ; antagonists & inhibitors ; genetics ; metabolism ; Tumor Necrosis Factor-alpha ; pharmacology

AIMTo determine the effect of saposin C (a known trophic domain of prosaposin) on proliferation, migration and invasion, as well as its effect on the expression of urokinase plasmonogen activator (uPA), its receptor (uPAR) and matrix metalloproteinases (MMP)-2 and -9 in normal and malignant prostate cells. In addition, we tested whether saposin C can activate p42/44 and stress-activated protein kinase/c-Jun NH2-terminal kinase (SAPK/JNK) signal transduction pathways of the mitogen-activated protein kinase (MAPK) superfamily.

METHODSWe employed Western blot analysis, phospho-specific antibodies, cell proliferation assay, reverse transcriptase-polymerase chain reaction, in vitro kinase assays and migration and invasion to determine the effect of saposin C on various biological behaviors of prostate stromal and cancer cells.

RESULTSSaposin C, in a cell type-specific manner, upregulates uPA/uPAR and immediate early gene c-Jun expression, stimulates cell proliferation, migration and invasion and activates p42/44 and SAPK/JNK MAPK pathways in prostate stromal and cancer cells. Normal prostate epithelial cells were not responsive to saposin C treatment in the above studies.

CONCLUSIONSaposin C functions as a multipotential modulator of diverse biological activities in prostate cancer and stromal cells. These results strongly suggest that saposin C functions as a potent growth factor for prostatic cells and may contribute to prostate carcinogenesis and/or the development of hormone-refractory prostate cancer.

Cell Division ; drug effects ; Enzyme Activation ; Humans ; Male ; Mitogen-Activated Protein Kinases ; metabolism ; Neoplasm Invasiveness ; Prostatic Neoplasms ; enzymology ; metabolism ; pathology ; Receptors, Cell Surface ; genetics ; Receptors, Urokinase Plasminogen Activator ; Reverse Transcriptase Polymerase Chain Reaction ; Saposins ; pharmacology ; Signal Transduction ; Stromal Cells ; enzymology ; metabolism ; pathology ; Up-Regulation ; Urokinase-Type Plasminogen Activator ; genetics

AIMTo investigate the possible role of manganese in the regulation of mitochondrial aconitase (mACON) activity human prostate carcinoma cell line PC-3 cells.

METHODSThe mACON enzymatic activities of human prostate carcinoma cell line PC-3 cells were determined using a reduced nicotinamide adenine dinucleotide-coupled assay. Immunoblot and transient gene expression assays were used to study gene expression of the mACON. The putative response element for gene expression was identified using reporter assays with site-directed mutagenesis and electrophoretic mobility-shift assays.

RESULTSIn vitro study revealed that manganese chloride (MnCl2) treatment for 16 h inhibited the enzymatic activity of mACON, which induced the inhibition of citrate utility and cell proliferation of PC-3 cells. Although results from transient gene expression assays showed that MnCl2 treatment upregulated gene translation by approximately 5-fold through the iron response element pathway, immunoblot and reporter assays showed that MnCl2 treatments inhibited protein and gene expression of mACON. This effect was reversed by co-treatment with ferric ammonium citrate. Additional reporter assays with site-directed mutagenesis and electrophoretic mobility-shift assays suggested that a putative metal response element in the promoter of the mACON gene was involved in the regulation of MnCl2 on the gene expression of mACON.

CONCLUSIONThese findings suggest that manganese acts as an antagonist of iron, disrupting the enzymatic activity and gene expression of mACON and citrate metabolism in the prostate.

Aconitate Hydratase ; antagonists & inhibitors ; genetics ; Actins ; genetics ; Adenosine Triphosphate ; metabolism ; Cell Line, Tumor ; Chlorides ; pharmacology ; Citrates ; metabolism ; DNA Primers ; Gene Expression Regulation, Enzymologic ; drug effects ; Gene Expression Regulation, Neoplastic ; drug effects ; Genes, Reporter ; Humans ; Iron ; metabolism ; Male ; Manganese Compounds ; pharmacology ; Mitochondria ; enzymology ; Prostatic Neoplasms ; enzymology

Glucosamine, a naturally occurring amino monosaccharide, has been reported to play a role in the regulation of apoptosis more than half century. However the effect of glucosamine on tumor cells and the involved molecular mechanisms have not been thoroughly investigated. Glucosamine enters the hexosamine biosynthetic pathway (HBP) downstream of the rate-limiting step catalyzed by the GFAT (glutamine:fluctose-6-phosphate amidotransferase), providing UDP-GlcNAc substrates for O-linked beta-N-acetylglucosamine (O-GlcNAc) protein modification. Considering that O-GlcNAc modification of proteasome subunits inhibits its activity, we examined whether glucosamine induces growth inhibition via affecting proteasomal activity. In the present study, we found glucosamine inhibited proteasomal activity and the proliferation of ALVA41 prostate cancer cells. The inhibition of proteasomal activity results in the accumulation of ubiquitinated proteins, followed by induction of apoptosis. In addition, we demonstrated that glucosamine downregulated proteasome activator PA28gamma and overexpression of PA28gamma rescued the proteasomal activity and growth inhibition mediated by glucosamine. We further demonstrated that inhibition of O-GlcNAc abrogated PA28gamma suppression induced by glucosamine. These findings suggest that glucosamine may inhibit growth of ALVA41 cancer cells through downregulation of PA28gamma and inhibition of proteasomal activity via O-GlcNAc modification.
Acetylglucosamine/chemistry/metabolism ; Alloxan/pharmacology ; Apoptosis/*drug effects ; Autoantigens/genetics/*metabolism ; Cell Line, Tumor ; Cell Proliferation/*drug effects ; Gene Expression Regulation, Neoplastic ; Glucosamine/*pharmacology ; Humans ; Male ; Phosphorylation ; Prostatic Neoplasms/*enzymology ; Proteasome Endopeptidase Complex/*antagonists & inhibitors/genetics/metabolism ; RNA, Small Interfering/genetics ; Ubiquitinated Proteins/metabolism

OBJECTIVETo study the role of PAK6 in prostate cancer by cloning PAK6-N terminal sequence into E.coli and preparing its polyclonal rabbit antibody to detect PAK6 expression in prostate cancer.

METHODSBased on human PAK6 cDNA sequence, we designed a pair of primers to amplify the PAK6-N terminal sequence by PCR. The PCR product was subcloned into the bacterial expression vector pGEX-4T-1 via EcoRI/XhoI sites, and the recombinant plasmids were identified by enzymatic cleavage followed by DNA sequence analysis. By transforming the expression vector into component E.coli BL21 cells, the GST-PAK6-N fusion protein was expressed with IPTG induction. Glutathione-Sepharose beads were used to purify GST- PAK6-N fusion protein. Anti-PAK6 polyclonal antibody was produced by immunizing rabbits with purified GST-PAK6 N-terminal fusion protein. Anti-PAK6 polyclonal antibody was purified by protein A beads and used for detection of PAK6 expression in 3 prostate cancer specimens.

RESULTS AND CONCLUSIONWe cloned PAK6-N terminal gene fragment successfully, purified GST-PAK6 N-terminal fusion protein, and obtained polyclonal rabbit PAK6 antibody. Immunohistochemistry indicated that PAK6 expressed in the stroma instead of the cancer cells in prostate cancer. All of the 3 prostate cancer specimens showed positive staining in the stroma, suggesting that PAK6 may participate in the stroma-cancer cell interaction in prostate cancer.

Aged ; Animals ; Antibodies, Monoclonal ; immunology ; isolation & purification ; Cloning, Molecular ; DNA, Complementary ; chemistry ; genetics ; Electrophoresis, Polyacrylamide Gel ; Gene Expression Regulation, Enzymologic ; Gene Expression Regulation, Neoplastic ; Humans ; Immunohistochemistry ; Male ; Polymerase Chain Reaction ; Prostatic Neoplasms ; enzymology ; genetics ; Rabbits ; Recombinant Fusion Proteins ; immunology ; metabolism ; Sequence Analysis, DNA ; p21-Activated Kinases ; genetics ; immunology ; metabolism