%0 Journal Article
%~ Pubmed
%A Singh, Jaskirat
%A Xie, Chanlu
%A Yao, Mu
%A Hua, Sheng
%A Vignarajan, Soma
%A Jardine, Greg
%A Hambly, Brett D
%A Sved, Paul
%A Dong, Qihan
%T Food extracts consumed in Mediterranean countries and East Asia reduce protein concentrations of androgen receptor, phospho-protein kinase B, and phospho-cytosolic phospholipase A(2)alpha in human prostate cancer cells.
%B The Journal of nutrition
%D 2010
%V 140
%N 4
%P 786-91
%@ 1541-6100
%X Active surveillance is an emerging management option for the rising number of men with low-grade, clinically localized prostate cancer. However, 30-40% of men on active surveillance will progress to high-grade disease over 5 y. With the ultimate aim of developing a food-based chemoprevention strategy to retard cancer progression in these otherwise healthy men, we have developed a blend of food extracts commonly consumed in Mediterranean countries and East Asia. The effect of the food extracts known as Blueberry Punch (BBP) on prostate cancer cell growth and key signaling pathways were examined in vitro and in vivo. BBP reduced prostate cancer cell growth in a dose-dependent manner (0.08-2.5%) at 72 h in vitro due to the reduction in cell proliferation and viability. Prostate cancer cell xenograft-bearing mice, administered 10% BBP in drinking water for 2 wk, had a 25% reduction in tumor volume compared with the control (water only). In vitro, BBP reduced protein concentrations in 3 signaling pathways necessary for the proliferation and survival of prostate cancer cells, namely androgen receptor, phospho-protein kinase B/protein kinase B, and phospho-cytosolic phospholipase A(2)alpha. The downstream effectors of these pathways, including prostate-specific antigen and glycogen synthase kinase 3beta, were also reduced. Thus, this palatable food supplement is a potential candidate for testing in clinical trials and may ultimately prove effective in retarding the progression of low-grade, early-stage prostate cancer in men managed by active surveillance.
%Z FOR Codes: 111201



%0 Journal Article
%~ Pubmed
%A Niknami, Marzieh
%A Vignarajan, Soma
%A Yao, Mu
%A Hua, Sheng
%A Witting, Paul K
%A Kita, Yoshihiro
%A Shimizu, Takao
%A Sved, Paul
%A Patel, Manish I
%A Dong, Qihan
%T Decrease in expression or activity of cytosolic phospholipase A2alpha increases cyclooxygenase-1 action: A cross-talk between key enzymes in arachidonic acid pathway in prostate cancer cells.
%B Biochimica et Biophysica Acta
%D 2010
%V 1801
%N 7
%P 731-7
%@ 0006-3002
%X The eicosanoid pathway is activated in many types of cancers including prostate. Eicosanoids are synthesized from intracellular arachidonic acid (AA), which is released from membrane glycerophospholipids mainly by the action of cytosolic phospholipase A(2)alpha (cPLA(2)alpha). Thus, targeting cPLA(2)alpha has been proposed as a treatment option. The aim of this study was to determine the effect of cPLA(2)alpha inhibition on cyclooxygenase (COX) expression and PGE(2) production. Inhibition of cPLA(2)alpha expression by siRNA or activity by Efipladib in prostate cancer cell lines (PC3 and LNCaP) led to an increase in COX-1 protein and PGE(2) levels in a dose-dependent manner from 24 to 72 h. The COX-2 response was less evident. Efipladib treatment increased COX-1 promoter transcriptional activity without changing the rate of COX-1 protein degradation. Treatment with Efipladib also led to a decrease in most LOX products (HETEs) as measured by LC/MS/MS. Replenishing 5- and 12-HETEs abolished Efipladib-induced COX-1 and PGE(2) levels. Decreasing 5- and 12-HETE production, as a result of treating cells with inhibitors MK886 and Baicalein, respectively, mimicked the effect of Efipladib on COX-1 and PGE(2) levels. Hence, the mechanism underlying the cPLA(2)alpha inhibition-induced COX-1 is likely due to a decrease in LOX products, which may exert a negative feedback on COX-1 gene expression in prostate cancer cells. Considering that PGE(2) is a potent promoter of cancer cell proliferation and survival, understanding the mechanism coupling cPLA(2)alpha with COX-1 is of potential clinical significance.
%Z FOR Codes: 111201 110104



%0 Journal Article
%~ Pubmed
%A Scott, Kieran F
%A Sajinovic, Mila
%A Hein, Juliann
%A Nixdorf, Sheri
%A Galettis, Peter
%A Liauw, Winston
%A de Souza, Paul
%A Dong, Qihan
%A Graham, Garry G
%A Russell, Pamela J
%T Emerging roles for phospholipase A2 enzymes in cancer.
%B Biochimie
%D 2010
%V 92
%N 6
%P 601-10
%@ 1638-6183
%X Phospholipase A(2) (PLA(2)) enzymes (EC3.1.4.4) regulate the release of biologically active fatty acids and lysophospholipids from membrane phospholipid pools. These lipids are also substrates for intracellular biochemical pathways that generate potent autocrine and paracrine lipid mediators such as the eicosanoids and platelet activating factor. These factors, in turn, regulate cell proliferation, survival, differentiation, motility, tissue vascularisation, and immune surveillance in virtually all tissues, functions that are subverted by cancer cells for tumour growth and metastasis. Thus the relevance of PLA(2)-dependent pathways to the genesis and progression of cancer has been of interest since their discovery and with recent technological advances, their role in tumourigenesis has become more tractable experimentally. Limited human genetic studies have not yet identified PLA(2) enzymes as classical mutated oncogenes or tumour suppressor genes. However, there is strong evidence that of the 22 identified human PLA(2) enzymes, ten of which have been studied in cancer to date, most are aberrantly expressed in a proportion of tumours derived from diverse organs. Correlative and functional studies implicate the expression of some secreted enzymes (sPLA(2)s), particularly the best studied enzyme Group IIA sPLA(2) in either tumour promotion or inhibition, depending on the organ involved and the biochemical microenvironment of tumours. As in immune-mediated inflammatory pathologies, genetic deletion studies in mice, supported by limited studies with human cells and tissues, have identified an important role for Group IVA PLA(2) in regulating certain cancers. Pharmacological intervention studies in prostate cancer suggest that hGIIA-dependent tumour growth is dependent on indirect regulation of Group IVA PLA(2). Group VI calcium-independent PLA(2) enzymes have also been recently implicated in tumourigenesis with in vitro studies suggesting multiple possible roles for these enzymes. Though apparently complex, further characterization of the regulatory relationships amongst PLA(2) enzymes, lipid mediator biosynthetic enzymes and the lipid mediators they produce during tumour progression is required to define the biochemical context in which the enzymes modulate cancer growth and development.
%Z FOR Codes: 111201



%0 Journal Article
%~ Pubmed
%A Assinder, Stephen J
%A Au, Edith
%A Dong, Qihan
%A Winnick, Clare
%T A novel splice variant of the beta-tropomyosin (TPM2) gene in prostate cancer.
%B Molecular carcinogenesis
%D 2010
%V 49
%N 6
%P 525-31
%@ 1098-2744
%X Decreased expression of high molecular weight isoforms of tropomyosin (Tm) is associated with oncogenic transformation and is evident in cancers, with isoform Tm1 seemingly an important tumor suppressor. Tm1 expression in prostate cancer has not previously been described. In this study, while demonstrating suppressed levels of Tm1 in the prostate cancer cell lines LNCaP, PC3, and DU-145 compared to normal prostate epithelial cell primary isolates (PrEC), a novel splice variant of the TPM2 gene was identified. Quantitative RT-PCR determined significantly greater levels of the transcript variant in all three prostate cancer cell lines than in normal prostate epithelial cells. Characterization of this novel variant demonstrated it to include exon 6b, previously thought unique to the muscle-specific beta-Tm isoform, with an exon arrangement of 1-2-3-4-5-6a-6b-7-8-10. Inclusion of exon 6b introduces a premature stop codon directly following the 6a-6b exon boundary. Western blot analysis demonstrated the presence of a truncated protein in prostate cancer cell lines that was absent in normal prostate epithelial cells. It is hypothesized that this truncated protein will result in suppression of Tm1 polymer formation required for actin filament association. The lack of Tm polymer-actin association will result in loss of the stable actin microfilament organization and stress fiber formation, a state associated with cell transformation.
%Z FOR Codes: 60103 60112



%0 Journal Article
%~ Pubmed
%A Yao, M
%A Taylor, R A
%A Richards, M G
%A Sved, P
%A Wong, J
%A Eisinger, D
%A Xie, C
%A Salomon, R
%A Risbridger, G P
%A Dong, Q
%T Prostate-regenerating capacity of cultured human adult prostate epithelial cells.
%B Cells, tissues, organs
%D 2010
%V 191
%N 3
%P 203-12
%@ 1422-6421
%X Experimentation with the progenitor/stem cells in adult prostate epithelium can be inconvenient due to a tight time line from tissue acquisition to cell isolation and to downstream experiments. To circumvent this inconvenience, we developed a simple technical procedure for culturing epithelial cells derived from human prostate tissue. In this study, benign prostate tissue was enzymatically digested and fractionated into epithelium and stroma, which were then cultured in the medium designed for prostate epithelial and stromal cells, respectively. The cultured cells were analyzed by immunocytochemical staining and flow cytometry. Prostate tissue-regenerating capacity of cultured cells in vitro was determined by co-culturing epithelial and stromal cells in dihydrotestosterone-containing RPMI. Cell lineages in formed acini-like structures were determined by immunohistochemistry. The culture of epithelial cells mainly consisted of basal cells. A minor population was negative for known lineage markers and positive for CD133. The culture also contained cells with high activity of aldehyde dehydrogenase. After co-culturing with stromal cells, the epithelial cells were able to form acini-like structures containing multiple cell lineages. Thus, the established culture of prostate epithelial cells provides an alternative source for studying progenitor/stem cells of prostate epithelium.
%Z FOR Codes: 1116



%0 Book Section
%A Young, Lei
%A Dong, Qihan
%T Targeted Amplification of Mutant Strands for Efficient Site-Directed Mutagenesis and Mutant Screening
%B Methods in Molecular Biology: In Vitro Mutagenesis Protocols
%D 2010
%C United States
%I Humana Press
%V 
%N Pt 2
%P 147-155
%@ 9781607616511
%E Braman, Jeff
%X 
%Z FOR Codes: 60199



%0 Journal Article
%~ Pubmed
%A Niknami, Marzieh
%A Dong, Qihan
%A Witting, Paul
%T Pitfalls in the use of arachidonic acid oxidation products to assign lipoxygenase activity in cancer cells.
%B Free radical research
%D 2009
%V 43
%N 10
%P 951-6
%@ 1029-2470
%X Arachidonic acid (AA) reaction with cyclooxygenase (COX) and lipoxygenases (LOX) yield eicosanoids that can mediate prostate cancer proliferation and enhance both tumour vascularization and metastasis. Increasingly measurement of eicosanoids with liquid chromatography is employed to implicate LOX activity in different biological systems and in particular link LOX activity to the progression of cancer in experimental models. This study demonstrates that simply identifying patterns of eicosanoid regio-isomerism is insufficient to designate LOX activity in prostate cancer cells and the analysis must include complete stereochemical assignment of the various isomers in order to validate the assignment of LOX activity.
%Z FOR Codes: 111299



%0 Journal Article
%~ Pubmed
%A Richards, Andrew
%A McGeechan, Kevin
%A Niknam, Marzieh
%A Salomon, Robert
%A Kurek, Caroline
%A Dong, Qihan
%A Patel, Manish I
%T Prolonging androgen sensitivity in prostate cancer - a role for COX inhibitors?
%B ANZ Journal of Surgery
%D 2009
%V 79
%N 9
%P 641-7
%@ 1445-2197
%X BACKGROUND: Advanced prostate cancer has long been known to respond to androgen deprivation, but disease inevitably progresses to become androgen independent. Lengthening the responsive period is an important, yet underinvestigated, clinical goal. This study aims to determine whether cyclooxygenase-2 (COX-2) inhibitors are potentially useful agents in prolonging androgen sensitivity. METHODS: The expression of COX-2 in human prostate surgical specimens, both benign and malignant, androgen dependent and independent, was determined by immunohistochemistry. Nude mice, in which prostate cancer xenografts had been established, were castrated and randomized to receive either COX-2 inhibitor or vehicle for 8 weeks. Time to androgen independence (AIPC), growth rate and rate of PSA rise were compared between groups. COX-2 expression, at the mRNA and protein level, was determined in the native xenograft cell line and in tissues of varying androgen sensitivity derived from the xenografts. RESULTS: In human tissues, COX-2 protein was expressed in prostate epithelium and was upregulated in prostate cancer and remained upregulated after androgen ablation and in the androgen-independent state. Tissue obtained from the LNCaP xenograft model showed variable COX-2 expression, with some evidence of downregulation in AIPC. The addition of a COX-2 inhibitor to castration does not lengthen the time to AIPC (P= 0.53), rate of tumour growth (P= 0.59) or rate of PSA rise (P= 0.34) in the LNCaP xenograft model. CONCLUSION: This study does not support a role for COX-2 inhibitors in prolonging androgen responsiveness in prostate cancer.
%Z FOR Codes: 111299 110323



%0 Journal Article
%~ Pubmed
%A Assinder, Stephen J
%A Dong, Qihan
%A Kovacevic, Zaklina
%A Richardson, Des R
%T The TGF-beta, PI3K/Akt and PTEN pathways: established and proposed biochemical integration in prostate cancer.
%B Biochemical Journal
%D 2009
%V 417
%N 2
%P 411-21
%@ 1470-8728
%X A key to the development of improved pharmacological treatment strategies for cancer is an understanding of the integration of biochemical pathways involved in both tumorigenesis and cancer suppression. Furthermore, genetic markers that may predict the outcome of targeted pharmacological intervention in an individual are central to patient-focused treatment regimens rather than the traditional 'one size fits all' approach. Prostate cancer is a highly heterogeneous disease in which a patient-tailored care program is a holy grail. This review will describe the evidence that demonstrates the integration of three established pathways: the tumour-suppressive TGF-beta (transforming growth factor-beta) pathway, the tumorigenic PI3K/Akt (phosphoinositide 3-kinase/protein kinase B) pathway and the tumour-suppressive PTEN (phosphatase and tensin homologue deleted on chromosome 10) pathway. It will discuss gene polymorphisms and somatic mutations in relevant genes and highlight novel pharmaceutical agents that target key points in these integrated pathways.
%Z FOR Codes: 111201



%0 Journal Article
%~ Pubmed
%A Salomon, Robert
%A Young, Lei
%A Macleod, Duncan
%A Yu, Xiao-Ling
%A Dong, Qihan
%T Probasin promoter-driven expression of ID1 is not sufficient for carcinogenesis in rodent prostate.
%B The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society
%D 2009
%V 57
%N 6
%P 599-604
%@ 0022-1554
%X Inhibitor of DNA-binding-1 (ID1) negatively regulates cell differentiation and senescence, and enhances cellular proliferation and angiogenesis. Elevated levels of ID1 have been found in a variety of cancers, including prostate cancer, but whether ID1 has a tumourigenic role remains to be established. We established heterozygous and homozygous ID1-transgenic mouse lines driven by the prostate-specific probasin promoter (-426 to +28 bp). Although elevated levels of ID1 were confirmed by RT-PCR, immunohistochemistry, and Western blot analysis, there were no morphological changes identified in the prostate of transgenic mice at 26 and 52 weeks. Thus, overexpression of ID1 alone is not sufficient to drive neoplastic change in mouse prostate.
%Z FOR Codes: 111201



%0 Journal Article
%~ Pubmed
%A Niknami, Marzieh
%A Patel, Manish
%A Witting, Paul K
%A Dong, Qihan
%T Molecules in focus: cytosolic phospholipase A2-alpha.
%B The International Journal of Biochemistry & Cell Biology
%D 2009
%V 41
%N 5
%P 994-7
%@ 1878-5875
%X Cytosolic phospholipase A(2)-alpha (cPLA(2)-alpha) cleaves its preferred substrate, arachidonic acid, at the sn-2 position of membrane glycerophospholipids. Stimulation of cells with agents that mobilize intracellular calcium and/or promote the phosphorylation of cPLA(2)-alpha leads to (i) translocation of the enzyme from cytosol to endoplasmic reticulum, Golgi apparatus and perinuclear membranes-where it associates with the arachidonic acid in close proximity to downstream eicosanoid-producing enzymes; and (ii) the change in configuration induced by phosphorylation increases the phospholipid binding affinity and arachidonic acid release. As a mediator of growth factors, cytokines, chemokines, and hormones that modulate survival and growth in various cell types, cPLA(2)-alpha has attracted considerable attention as a potential therapeutic target in control of inflammation and cancer. The importance of the enzyme may have been underestimated by the relatively normal phenotype in the enzyme knockout animals. A clear phenotype has emerged when these knockout animals are used as models of various diseases.
%Z FOR Codes: 111201



%0 Journal Article
%~ Pubmed
%A Assinder, Stephen J
%A Dong, Qihan
%A Mangs, Helena
%A Richardson, Des R
%T Pharmacological targeting of the integrated protein kinase B, phosphatase and tensin homolog deleted on chromosome 10, and transforming growth factor-beta pathways in prostate cancer.
%B Molecular Pharmacology
%D 2009
%V 75
%N 3
%P 429-36
%@ 1521-0111
%X Prostate cancer is a highly heterogenous disease in which a patient-tailored care program is much desired. Central to this goal is the development of novel targeted pharmacological interventions. To develop these treatment strategies, an understanding of the integration of cellular pathways involved in both tumorigenesis and tumor suppression is crucial. Of further interest are the events elicited by drug treatments that exploit the underlying molecular pathology in cancer. This review briefly describes the evidence that suggests integration of three established pathways: the tumorigenic phosphoinositide 3-kinase/protein kinase B (AKT) pathway, the tumor suppressive phosphatase and tensin homolog deleted on chromosome 10 pathway, and the tumor suppressive transforming growth factor-beta pathway. More importantly, we discuss novel pharmaceutical agents that target key points of integration in these three pathways. These new therapeutic strategies include the use of agents that target iron to inhibit proliferation via multiple mechanisms and suppression of AKT by cytosolic phospholipase A(2)-alpha inhibitors.
%Z FOR Codes: 111201



%0 Journal Article
%A Nikinami, M
%A Patel, M
%A Witting, Paul
%A Dong, Q
%T Aberrant activation of arachidonic acid and eicosanoid pathways-targets for treating prostate cancer
%B Recent Patents on Endocrine, Metabolic & Immune Drug Discovery
%D 2008
%C United Kingdom
%I Bentham Science Publishers Ltd
%V 2
%N 
%P 9-15
%@ 1872-2148
%X 
%Z FOR Codes: 110306



%0 Journal Article
%~ Pubmed
%A Patel, Manish I
%A Kurek, Caroline
%A Dong, Qihan
%T The arachidonic acid pathway and its role in prostate cancer development and progression.
%B The Journal of Urology
%D 2008
%V 179
%N 5
%P 1668-75
%@ 1527-3792
%X PURPOSE: The arachidonic acid pathway incorporates phospholipase, cyclooxygenase, lipoxygenase and epoxygenase enzymes. This pathway has been shown to have a major role in the development and progression of a number of cancers, including prostate cancer. We discuss the current status of research of this pathway in the area of prostate cancer, ranging from preclinical in vitro studies to human clinical trials. MATERIALS AND METHODS: We performed an online search of the current and past peer reviewed literature on prostate cancer and arachidonic acid, phospholipase, cyclooxygenase, lipoxygenase, epoxygenase, platelet activating factor, prostaglandin and eicosanoid. We retrieved and evaluated all full-length articles published in English from the 1980s to January 2007. RESULTS: Epidemiological evidence suggested that nonsteroidal anti-inflammatory drugs may decrease the risk of prostate cancer. This effect, presumably through the inhibition of cyclooxygenase-2, has been validated in preclinical studies. Cyclooxygenase-2 inhibition has also decreased the rate of prostate specific antigen increase in men with biochemical recurrence after treatment for prostate cancer. Although lipoxygenase and secretory phospholipase A2 inhibition was also effective for decreasing prostate cancer growth in preclinical studies, to our knowledge these strategies have not yet been used in clinical trials. Cytosolic phospholipase A2, platelet activating factor and epoxygenase need further investigation to determine a role in prostate cancer. CONCLUSIONS: Evolving data suggest a significant role for some areas of the arachidonic acid pathway in prostate cancer. Inhibiting 1 or a number of these enzymes in combination may hold promise for future prostate cancer treatment.
%Z FOR Codes: 111201



%0 Journal Article
%~ Pubmed
%A Patel, Manish I
%A Singh, Jaskirat
%A Niknami, Marzieh
%A Kurek, Caroline
%A Yao, Mu
%A Lu, Sasa
%A Maclean, Fiona
%A King, Nicholas J C
%A Gelb, Michael H
%A Scott, Kieran F
%A Russell, Pamela J
%A Boulas, John
%A Dong, Qihan
%T Cytosolic Phospholipase A2-{alpha}: A Potential Therapeutic Target for Prostate Cancer.
%B Clinical Cancer Research
%D 2008
%V 14
%N 24
%P 8070-9
%@ 1078-0432
%X PURPOSE: Cytosolic phospholipase A2-alpha (cPLA(2)-alpha) provides intracellular arachidonic acid to supply both cyclooxygenase and lipoxygenase pathways. We aim to determine the expression and activation of cPLA(2)-alpha in prostate cancer cell lines and tissue and the effect of targeting cPLA(2)-alpha in vitro and in vivo. EXPERIMENTAL DESIGN: The expression of cPLA(2)-alpha was determined in prostate cancer cells by reverse transcription-PCR, Western blot, and immunocytochemistry. Growth inhibition, apoptosis, and cPLA(2)-alpha activity were determined after inhibition with cPLA(2)-alpha small interfering RNA or inhibitor (Wyeth-1). Cytosolic PLA(2)-alpha inhibitor or vehicle was also administered to prostate cancer xenograft mouse models. Finally, the expression of phosphorylated cPLA(2)-alpha was determined by immunohistochemistry in human normal, androgen-sensitive and androgen-insensitive prostate cancer specimens. RESULTS: cPLA(2)-alpha is present in all prostate cancer cells lines, but increased in androgen-insensitive cells. Inhibition with small interfering RNA or Wyeth-1 results in significant reductions in prostate cancer cell numbers, as a result of reduced proliferation as well as increased apoptosis, and this was also associated with a reduction in cPLA(2)-alpha activity. Expression of cyclin D1 and phosphorylation of Akt were also observed to decrease. Wyeth-1 inhibited PC3 xenograft growth by approximately 33% and again, also reduced cyclin D1. Immunohistochemistry of human prostate tissue revealed that phosphorylated cPLA(2)-alpha is increased when hormone refractory is reached. CONCLUSIONS: Expression and activation of cPLA(2)-alpha are increased in the androgen-insensitive cancer cell line and tissue. Inhibition of cPLA(2)-alpha results in cells and xenograft tumor growth inhibition and serves as a potentially effective therapy for hormone refractory prostate cancer.
%Z FOR Codes: 111201



%0 Journal Article
%~ Pubmed
%A Young, Lei
%A Salomon, Robert
%A Au, Wendy
%A Allan, Charles
%A Russell, Peter
%A Dong, Qihan
%T Ornithine decarboxylase (ODC) expression pattern in human prostate tissues and ODC transgenic mice.
%B The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society
%D 2006
%V 54
%N 2
%P 223-9
%@ 0022-1554
%X Ornithine decarboxylase (ODC) is the key enzyme in the polyamine synthesis pathway and is overexpressed in a variety of cancers. We have performed a detailed immunostaining analysis of the expression of ODC in normal, benign prostatic hyperplasia (BPH), and cancerous prostate tissues. We conclude that ODC is overexpressed in both BPH and neoplastic tissues and that ODC overexpression appears to be an early event in prostate carcinogenesis. The extent of overexpression decreases as cancer progresses. Interestingly, ODC overexpression was also detected in patients who underwent androgen ablation therapy, suggesting ODC overexpression may contribute to the androgen-independent survival of prostate cancer cells. ODC is perinuclear localized in BPH samples but is diffusely cytoplasmic in cancer samples. Having shown ODC overexpression in human prostate cancer, we developed prostate-specific ODC transgenic mice to further investigate whether ODC overexpression alone is a causal factor in prostate carcinogenesis. RT-PCR and immunostaining confirmed that ODC was overexpressed in a subset of prostate epithelial cells. Although minor nucleoli enlargements in some tissues were detected, gross morphological changes were not observed in transgenic prostates. Therefore, overexpression of ODC alone in this subset of prostate epithelial cells is not sufficient to induce prostate carcinogenesis.
%Z FOR Codes: 110199



%0 Journal Article
%~ Pubmed
%A Lim, Wee Guan
%A Tan, Bee Jen
%A Zhu, Yimin
%A Zhou, Shufeng
%A Armstrong, Jeffrey S
%A Li, Qiu Tian
%A Dong, Qihan
%A Chan, Eli
%A Smith, Derek
%A Verma, Chandra
%A Tan, Seng-Lai
%A Duan, Wei
%T The very C-terminus of PRK1/PKN is essential for its activation by RhoA and downstream signaling.
%B Cellular signalling
%D 2006
%V 18
%N 9
%P 1473-81
%@ 0898-6568
%X PRK1 is a lipid- and Rho GTPase-activated serine/threonine protein kinase implicated in the regulation of receptor trafficking, cytoskeletal dynamics and tumorigenesis. Although Rho binding has been mapped to the HR1 region in the regulatory domain of PRK1, the mechanism involved in the control of PRK1 activation following Rho binding is poorly understood. We now provide the first evidence that the very C-terminus beyond the hydrophobic motif in PRK1 is essential for the activation of this kinase by RhoA. Deletion of the HR1 region did not completely abolish the binding of PRK1-DeltaHR1 to GTPgammaS-RhoA nor the activation of this mutant by GTPgammaS-RhoA in vitro. In contrast, removing of the last six amino acid residues from the C-terminus of PRK1 or truncating of a single C-terminal residue from PRK1-DeltaHR1 completely abrogated the activation of these mutants by RhoA both in vitro and in vivo. The critical dependence of the very C-terminus of PRK1 on the signaling downstream of RhoA was further demonstrated by the failure of the PRK1 mutant lacking its six C-terminal residues to augment lisophosphatidic acid-elicited neurite retraction in neuronal cells. Thus, we show that the HR1 region is necessary but not sufficient in eliciting a full activation of PRK1 upon binding of RhoA. Instead, such activation is controlled by the very C-terminus of PRK1. Our results also suggest that the very C-terminus of PRK1, which is the least conserved among members of the protein kinase C superfamily, is a potential drug target for pharmacological intervention of RhoA-mediated signaling pathways.
%Z FOR Codes: 110306 111201



%0 Journal Article
%~ Isi
%A Zhu, Y. M.
%A Dong, Q. H.
%A Tan, B. J.
%A Lim, W. G.
%A Zhou, S. F.
%A Duan, W.
%T The PKC alpha-D294G mutant found in pituitary and thyroid tumors fails to transduce extracellular signals.
%B Cancer Research
%D 2005
%C United States
%I American Association for Cancer Research
%V 65
%N 11
%P 4520-4524
%@ 0008-5472
%X 
%Z FOR Codes: 111201



%0 Journal Article
%~ Pubmed
%A Dong, Qihan
%A Patel, Manish
%A Scott, Kieran F
%A Graham, Garry G
%A Russell, Pamela J
%A Sved, Paul
%T Oncogenic action of phospholipase A2 in prostate cancer.
%B Cancer Letters
%D 2005
%V 240
%N 1
%P 9-16
%@ 0304-3835
%X Mortality from prostate cancer is a result of progression of cancer cells to become androgen-refractory and metastatic. Eicosanoid products of the cyclooxygenase (COX) and lipoxygenase (LOX) pathways are important mediators of the proliferation of prostate cancer cells in culture and regulate tumour vascularisation and metastasis in animal models. Pharmacological agents that block either COX or LOX products effectively reduce the size of prostate cancer xenografts. Recently, phospholipase A(2) (PLA(2)) enzymes, which regulate the provision of arachidonic acid to both COX- and LOX-derived eicosanoids, are found to also regulate the growth of prostate cancer cells and tumours, with one enzyme, secreted PLA(2)-IIA, being increased in prostate cancer tissues. Annexin A1 and A2, known inhibitors of cytosolic phospholipase A(2)-alpha activity, are absent in prostate cancer tissues. We propose that PLA(2) enzyme function is dysregulated by aberrant up regulation of secreted enzymes and downregulation of endogenous inhibitors of cytosolic phospholipase A(2) activity in prostate cancer and that this dysregulation contributes to the pathogenesis of prostate cancer. Thus, in addition to COX and LOX enzymes, PLA(2) enzymes represent important targets for the treatment of prostate cancer.
%Z FOR Codes: 111201



%0 Journal Article
%~ Pubmed
%A Singh, Jas
%A Manickam, Pachiappan
%A Shmoish, Michael
%A Natik, Sara
%A Denyer, Gareth
%A Handelsman, David
%A Gong, Da-Wei
%A Dong, Qihan
%T Annotation of androgen dependence to human prostate cancer-associated genes by microarray analysis of mouse prostate.
%B Cancer Letters
%D 2005
%V 237
%N 2
%P 298-304
%@ 0304-3835
%X In silico methods and array technologies have identified genes differentially expressed in prostate cancer. Biological functions of the identified genes are often unclear. Considering the biological significance of androgens in prostate cancer, we profiled the prostate transcripts of congenital androgen-deficient mice with or without androgen replacement in vivo using murine gene expression array. In parallel genes differentially expressed in human prostate cancer were identified by Digital Differential Display and the Serial Analysis of Gene Expression. Androgen dependence of the identified genes was then determined by the steady-state mRNA levels of the murine orthologs in response to androgen treatment. The annotation is supported by the finding that some of the androgen target genes have been reported previously with independent experiments.
%Z FOR Codes: 111201



%0 Journal Article
%~ Pubmed
%A Singh, Jaskirat
%A Young, Lei
%A Handelsman, David J
%A Dong, Qihan
%T Molecular cloning and characterization of a novel androgen repressible gene expressed in the prostate epithelium.
%B Gene
%D 2005
%V 348
%N 
%P 55-63
%@ 0378-1119
%X Prostate cancer deaths are due to functional escape of prostate cancer cells from their original androgen-dependent growth. To better understand the origin and evolution of hormone-refractory prostate cancer, it is important to identify and characterize genes expressed in the androgen-deprived prostate. We have verified that the rudimentary prostate of congenital androgen deficient mice (hpg) is indeed androgen independent. Using suppression subtractive hybridization between mRNA derived from prostates of hypogonadal (hpg) with or without 14 days of testosterone replacement we have cloned a novel gene from the hpg prostate, termed ADMP (for androgen down regulated gene expressed in mouse prostate), that is down regulated by androgens. ADMP expression is strong in hpg mouse prostate, weak in mature castrated mouse prostate and absent in normal intact or androgen-replaced hpg mouse prostates. While ADMP expression is androgen independent in the hpg prostate, it appears to be androgen-dependent in the kidney and brain of normal intact mouse suggesting tissue specific regulation of ADMP by androgens. Human ADMP mRNA expression is suppressed by androgens in the androgen-sensitive LNCaP cell line. The predicted mouse and human protein of 76 amino acids shares sequence similarity to a putative G-protein coupled receptor indicating its possible role in signal transduction. Human ADMP expression was seen predominantly in the prostate epithelium with weaker expression in the fibroblasts and endothelial cells. Cloning and characterization of ADMP has made it feasible to determine its prospective role in the absence of androgens in prostate cancer.
%Z FOR Codes: 111201



%0 Journal Article
%~ Pubmed
%A Patel, Manish I
%A Tuckerman, Rodney
%A Dong, Qihan
%T A Pitfall of the 3-(4,5-dimethylthiazol-2-yl)-5(3-carboxymethonyphenol)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay due to evaporation in wells on the edge of a 96 well plate.
%B Biotechnology letters
%D 2005
%V 27
%N 11
%P 805-8
%@ 0141-5492
%X The 3-(4,5-dimethylthiazol-2-yl)-5(3-carboxymethonyphenol)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) calorimetric assay is replacing the traditional 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay as a fast, one-step assay of cell viability. We have observed that evaporation of the outer wells of a 96 well plate increases the absorbancy by 52% compared to the inner wells. Filling the outer 2 rows of wells with media and replacement of the media prior to addition of the MTS reagent will, however, correct this inaccuracy.



%0 Journal Article
%~ Pubmed
%A Young, Lei
%A Dong, Qihan
%T Development of a murine prostatespecific 2-in-1 inducible bicistronic expression vector.
%B Biotechnology letters
%D 2005
%V 27
%N 12
%P 823-8
%@ 0141-5492
%X Transgenic research often suffers from the lack of strong tissue specific promoters and the lack of suitable antibodies for transgene detection. We have now constructed a novel prostate specific 2-in-1 Tetracycline-off (Tet-off), bicistronic expression vector, designated PbTetOIE, for transgenic research. The vector allows potent induction as well as inducible suppression of transgene expression in the prostate epithelial cells, and also allows the detection of transgene expression at the cellular level through the detection of the internal enhanced green fluorescent protein (EGFP) downstream of the transgene.
%Z FOR Codes: 111201



%0 Journal Article
%~ Pubmed
%A Young, Lei
%A Dong, Qihan
%T Two-step total gene synthesis method.
%B Nucleic Acids Research
%D 2004
%V 32
%N 7
%P e59
%@ 1362-4962
%X In the post-genomic era, the ability to synthesize any arbitrary DNA sequence is increasingly in demand. A bottleneck in current gene synthesis technologies is the associated cost, due primarily to the high cost of oligonucleotides synthesis and post-synthesis sequencing. In the present paper, an improved method for low-cost gene synthesis that combines dual asymmetrical PCR and overlap extension PCR is presented, which enables any DNA sequence to be synthesized error free. Additionally, the method is easily amenable to automation.



%0 Journal Article
%~ Pubmed
%A Sved, Paul
%A Scott, Kieran F
%A McLeod, Duncan
%A King, Nicholas J C
%A Singh, Jas
%A Tsatralis, Tania
%A Nikolov, Blagoy
%A Boulas, John
%A Nallan, Laxman
%A Gelb, Michael H
%A Sajinovic, Mila
%A Graham, Garry G
%A Russell, Pamela J
%A Dong, Qihan
%T Oncogenic action of secreted phospholipase A2 in prostate cancer.
%B Cancer Research
%D 2004
%V 64
%N 19
%P 6934-40
%@ 0008-5472
%X Mortality from prostate cancer is associated with progression of tumors to androgen-independent growth and metastasis. Eicosanoid products of both the cyclooxygenase (COX) and lipoxygenase (LOX) pathways are important mediators of the proliferation of prostate cancer cells in culture and regulate tumor vascularization and metastasis in animal models. Pharmacologic agents that block either COX or LOX products effectively reduce the size of prostate cancer xenografts. Phospholipase A(2) (PLA(2)) enzymes regulate the provision of arachidonic acid to both COX- and LOX-derived eicosanoids, and a secreted form of the enzyme (sPLA(2)-IIA) is elevated in prostate cancer tissues. Here, we show by immunohistochemistry, in patients receiving androgen ablation therapy, that sPLA(2)-IIA remains elevated in remaining cancer cells relative to benign glands after treatment. Furthermore, sPLA(2)-IIA expression seen in benign glands is substantially decreased after androgen depletion, whereas cytosolic PLA(2)-alpha (cPLA(2)-alpha) levels are unchanged. sPLA(2)-IIA mRNA expression is detectable and inducible by androgen (0.01-10 nmol/L) in the androgen-sensitive cell line LNCaP, and exogenous addition of sPLA(2)-IIA (1-100 nmol/L), but not an inactive sPLA(2)-IIA mutant (H(48)Q), results in a dose-dependent increase in cell numbers or the fraction of cells in G(2)-M phase, which is inhibited by sPLA(2)-IIA-selective inhibitors. The effect of exogenous sPLA(2)-IIA can also be blocked by inhibition of cPLA(2)-alpha, suggesting a role for cPLA(2)-alpha in mediating sPLA(2)-IIAlpha action. sPLA(2)-IIA inhibitors suppressed basal proliferation in LNCaP cells and in the androgen-independent, sPLA(2)-positive cell line PC3 but not in the sPLA(2)-IIA-negative androgen-independent cell line DU145. Established PC3 xenograft tumors grew more slowly in mice treated with sPLA(2)-IIA inhibitors than those treated with saline only. The PLA(2) enzymes, and sPLA(2)-IIA in particular, thus represent important targets for the treatment of sPLA(2)-IIA-positive androgen-independent prostate cancer.



%0 Journal Article
%~ Pubmed
%A Young, Lei
%A Dong, Qihan
%T TAMS technology for simple and efficient in vitro site-directed mutagenesis and mutant screening.
%B Nucleic Acids Research
%D 2003
%V 31
%N 3
%P e11
%@ 1362-4962
%X Site-directed mutagenesis is an invaluable tool for functional studies and genetic engineering. However, most current protocols require the target DNA to be cloned into a plasmid vector before mutagenesis can be performed, and none of them are effective for multiple-site mutagenesis. We now describe a method that allows mutagenesis on any DNA template (eg. cDNA, genomic DNA and plasmid DNA), and is highly efficient for multiple-site mutagenesis (up to 100%). The technology takes advantage of the requirement that, in order for DNA polymerases to elongate, it is crucial that the 3' sequences of the primers match the template perfectly. When two outer mutagenic oligos are incorporated together with the desired mutagenic oligos into the newly synthesised mutant strand, they serve as anchors for PCR primers which have 3' sequences matching the mutated nucleotides, thus amplifying the mutant strand only. The same principle can also be used for mutant screening.
%Z FOR Codes: 111299



%0 Journal Article
%~ Pubmed
%A Singh, Jaskirat
%A Young, Lei
%A Handelsman, David J
%A Dong, Qihan
%T Prostate epithelial expression of a novel androgen target gene.
%B Journal of andrology
%D 2002
%V 23
%N 5
%P 652-60
%@ 0196-3635
%X To better understand the role of androgens in prostate development and disease it is important to characterize androgen-regulated genes in the prostate. Using suppression subtractive hybridization between congenitally androgen-deficient (hpg) and androgen-replaced hpg mouse prostates, we have cloned a novel androgen up-regulated gene from mouse prostate (AUMP). The messenger RNA sequence of AUMP consists of 805 nucleotides with an open reading frame of 408 base pairs. In non-hpg mice with normal androgen levels, AUMP is selectively expressed in the prostate, as shown by reverse transcriptase-polymerase chain reaction and Northern blot analysis of 9 organs. Depletion of androgens via castration of mature mice resulted in loss of AUMP expression, whereas testosterone replacement restored it. Tissue in situ hybridization localized AUMP expression to the luminal epithelial cells of the androgen-sufficient prostate. Database searches indicate that AUMP codes for a novel protein that shares approximately 65% similarity and 35% identity to palmitoyl protein thioesterase of human, rat, mouse, and bovine. A motif for protein-transport protein, which promotes translocation as well as integration of secretory proteins into membrane, is also present. Further efforts will be made to obtain the human homologue of AUMP that will enable evaluation of its role in normal and diseased human prostate.



%0 Journal Article
%~ Pubmed
%A Foxley, G J
%A Dong, Q
%A Handelsman, D J
%T Quantitative reverse transcriptase polymerase chain reaction assay for mouse androgen receptor mRNA.
%B Endocrine
%D 2001
%V 15
%N 2
%P 193-8
%@ 0969-711X
%X A quantitative reverse transcriptase polymerase chain reaction (RT-PCR) assay for mouse androgen receptor (AR) mRNA was developed to study relative changes in AR gene expression. Serial dilutions of a standard comprising a fragment of the ampicillin resistance gene flanked by the primer sequences of the AR mRNA were added to a constant amount of total RNA for RT-PCR. Primers were designed to generate a 541-bp fragment of mouse AR mRNA (target [T]) and a 460-bp fragment of the standard (S). PCR products were resolved by gel electrophoresis and quantitated by densitometry. A standard curve was generated for each sample by plotting the logarithm of T/S products vs the logarithm of the amount of S added. The amount of T was determined from the standard curve where intensities of PCR products of T and S were equal. The assay was validated by measuring the relative abundance of AR mRNA in 10 mouse tissues, and results were consistent with studies of AR expression in rat tissues. Assay reproducibility, tested by repeating assays on four different tissues on different days from the RT step, had a coefficient of variation of 6-16%. The current assay is thus both reproducible and valid in quantitation of mouse AR mRNA.



%0 Journal Article
%~ Pubmed
%A Chetcuti, A
%A Margan, S
%A Mann, S
%A Russell, P
%A Handelsman, D
%A Rogers, J
%A Dong, Q
%T Identification of differentially expressed genes in organ-confined prostate cancer by gene expression array.
%B The Prostate
%D 2001
%V 47
%N 2
%P 132-40
%@ 0270-4137
%X BACKGROUND: To understand the molecular mechanisms underlying prostate cancer, we have utilized the gene expression array to search for genes whose expression is altered in this disease. METHODS: RNA quality from manual microdissected tissue was compared with that from microselected tissue by electrophoresis. For array analysis, malignant and normal prostate epithelium was enriched using microselection technique from prostate cancer and the peripheral zone of a normal prostate. Identical array membrane was hybridized to labeled cancer and normal cDNA, respectively. The differentially expressed gene was further evaluated by RT-PCR. RESULTS: Microdissection, but not microselection, causes visible degradation to RNA. Of the 588 genes on the membrane, 87 genes yielded significant signals. Based on a three fold difference relative to normal prostate tissue, 1 gene was overexpressed and 12 genes underexpressed in prostate cancer. Of them, five showed statistically significant reduction in mRNA levels in six prostate cancer specimens compared with seven normal prostate specimens. These five genes are glutathione S-transferase M1 (GSTM1), monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor-alpha receptor-1 (TNFR-1), transforming growth factor beta3 (TGF-beta3), and inhibitor of DNA binding-1 (ID-1). CONCLUSIONS: GST-based metabolism, cytokine MCP-1 and TNFR-1, and TGF-beta3 signaling pathways, and some helix-loop-helix nuclear proteins could be potentially important in organ-confined prostate cancer and deserve further investigation.



%0 Journal Article
%~ Pubmed
%A Chetcuti, A
%A Margan, S H
%A Russell, P
%A Mann, S
%A Millar, D S
%A Clark, S J
%A Rogers, J
%A Handelsman, D J
%A Dong, Q
%T Loss of annexin II heavy and light chains in prostate cancer and its precursors.
%B Cancer Research
%D 2001
%V 61
%N 17
%P 6331-4
%@ 0008-5472
%X Annexin II mRNA coding for a calcium binding protein was found to be absent in prostate cancer by subtractive hybridization and Northern analysis. In contrast to high expression in normal and benign hyperplastic glandular and basal epithelium, Annexin II heavy (p36) and light (p11) chains in 31/31 prostate cancer specimens were lost immunohistochemically. In glands involved by prostate intraepithelial neoplasia, 65% lost both chains in glandular epithelial cells, whereas basal cells were all positively stained. Southern analysis of cancer DNA showed no noticeable deletion in p36 gene. LNCaP cells treated with 5-azacytidine re-expressed p36, suggesting methylation could be responsible for the silencing.



%0 Journal Article
%A Chua, E
%A Wu, WM
%A Tran, KT
%A McCarthy, SW
%A Lauer, CS
%A Dubourdieu, D
%A Packham, N
%A O'Brien, CJ
%A Turtle, JR
%A Dong, Q
%T Prevalence and distribution of ret/ptc 1, 2, and 3 in papillary thyroid carcinoma in New Caledonia and Australia
%B The Journal of Clinical Endocrinology & Metabolism
%D 2000
%C 
%I Endocrine Society, Bethesda USA
%V 85
%N 
%P 2733-2739
%@ 0021-972X
%X 



%0 Journal Article
%A Chua, E
%A Young, L
%A Wu, WM
%A Turtle, JR
%A Dong, Q
%T Cloning of TC-1 (C8orf4), a novel gene found to be overexpressed in thyroid cancer
%B Genomics
%D 2000
%C 
%I Academic Press Inc
%V 69
%N 
%P 342-347
%@ 0888-7543
%X 



%0 Journal Article
%A Margan, SH
%A Handelsman, DJ
%A Mann, S
%A Russell, P
%A Rogers, J
%A Khadra, MH
%A Dong, Q
%T Quality of nucleic acids extracted from fresh prostatic tissue obtained from TURP procedures
%B Journal of Urology
%D 2000
%C 
%I Lippincott Williams & Wilkins
%V 163
%N 
%P 613-615
%@ 0022-5347
%X