Prostate cancer cells show elevated urokinase receptor in a mouse model of metastasis

BACKGROUND: The urokinase receptor (uPAR) governs several functions necessary during invasion and metastasis such as motility, degradation of the extracellular matrix and adhesion. This receptor has been recently associated with clinical prostate cancer progression. Experimentally, inhibition of uPAR reduces colonization of extra-prostatic sites in animal models. Our objective in this study was to compare uPAR expression in orthotopic vs. metastatic foci in vivo and to examine at the cellular level how uPAR might promote early stages of metastasis. RESULTS: We show that uPAR staining is significantly greater in regional lymph node metastases than in the intraprostatic tumor mass. Using transient over-expression, we found that uPAR increases in vitro motility and chemotactic invasion. Finally, we demonstrate that uPAR is up-regulated by a significant subpopulation prostate cancer cells following matrix detachment and maintenance in suspension and we provide evidence that prostate cancer cells with elevations in uPAR have an enhanced resistance to anoikis. CONCLUSION: These data provide new evidence that uPAR can be induced by cancer cells during metastasis in vivo and that this elevated uPAR enhances resistance to anoikis in vitro

The superoxide scavenger TEMPOL induces urokinase receptor (uPAR) expression in human prostate cancer cells

There is little understanding of the effect that reactive oxygen metabolites have on cellular behavior during the processes of invasion and metastasis. These oxygen metabolites could interact with a number of targets modulating their function such as enzymes involved in basement membrane dissolution, adhesion molecules involved in motility or receptors involved in proliferation. We investigated the effect of increased scavenging of superoxide anions on the expression of the urokinase receptor (uPAR) in PC-3M human prostate cancer cells. Urokinase receptor is a GPI-linked cell surface molecule which mediates multiple functions including adhesion, proliferation and pericellular proteolysis. Addition of the superoxide scavenger 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy (TEMPOL) to PC-3M cultures stimulated expression of uPAR protein peaking between 48 and 72 hours. Cell surface expression of the uPAR was also increased. Surprisingly, uPAR transcript levels increased only slightly and this mild increase did not coincide with the striking degree of protein increase. This disparity indicates that the TEMPOL effect on uPAR occurs through a post-transcriptional mechanism. TEMPOL presence in PC-3M cultures reduced intracellular superoxide-type species by 75% as assayed by NBT dye conversion; however this reduction significantly diminished within hours following TEMPOL removal. The time gap between TEMPOL treatment and peak uPAR protein expression suggests that reduction of reactive oxygen metabolites in prostate cancer cells initiates a multistep pathway which requires several hours to culminate in uPAR induction. These findings reveal a novel pathway for uPAR regulation involving reactive oxygens such as superoxide anion

A doxycycline-inducible urokinase receptor (uPAR) upregulates uPAR activities including resistance to anoikis in human prostate cancer cell lines

<p>Abstract</p> <p>Background</p> <p>The urokinase receptor (uPAR) mediates a diverse array of cellular processes including several events involved in prostate cancer metastasis. Many of these activities are initiated or enhanced by uPAR binding to its proteolytic ligand, urokinase (uPA). Our objective in this study was to generate and test an inducible lentiviral system capable of expressing uPAR and DsRed fluorescent protein in human prostate cancer cell lines.</p> <p>Results</p> <p>A DsRed-uPAR fusion construct was inserted into a lentiviral vector. Transduction of human prostate cancer cell lines with this virus and with a virus containing a reverse-tetracycline transactivator (rt-TA) resulted in a stable transgene which induced both uPAR and DsRed proteins in a dose-responsive fashion upon stimulation with doxycycline. Immunoblots and immunofluorescence studies indicated no detectable uPAR expression in non-induced prostate cancer cell lines. Cells with induced-uPAR demonstrated increased cellular adhesion to the matrix substrate vitronectin and increased net cell proliferation compared to uninduced cells. Finally, induced uPAR-expressing prostate cancer cells were resistant to anoikis over an extended time period when grown in suspension.</p> <p>Conclusion</p> <p>This doxycycline-inducible lentivirus system produces titerable levels of biologically active uPAR <it>in vitro</it>. This tool can be used to dissect cellular events following induction of uPAR in prostate cancer cells.</p

Potential adverse effects of long term use of Proton Pump Inhibitors

Proton-Pump Inhibitors (PPIs) have changed the therapy of numerous upper gastrointestinal tract disorders; but their use is not without risk of adverse effects. Recent studies suggest more serious adverse events with chronic use of PPIs. Because of these risks, clinicians should reassess individual patient’s needs for chronic PPI therapy

Structure-Based Development of Small Molecule PFKFB3 Inhibitors: A Framework for Potential Cancer Therapeutic Agents Targeting the Warburg Effect

Cancer cells adopt glycolysis as the major source of metabolic energy production for fast cell growth. The HIF-1-induced PFKFB3 plays a key role in this adaptation by elevating the concentration of Fru-2,6-BP, the most potent glycolysis stimulator. As this metabolic conversion has been suggested to be a hallmark of cancer, PFKFB3 has emerged as a novel target for cancer chemotherapy. Here, we report that a small molecular inhibitor, N4A, was identified as an initial lead compound for PFKFB3 inhibitor with therapeutic potential. In an attempt to improve its potency, we determined the crystal structure of the PFKFB3•N4A complex to 2.4 Å resolution and, exploiting the resulting molecular information, attained the more potent YN1. When tested on cultured cancer cells, both N4A and YN1 inhibited PFKFB3, suppressing the Fru-2,6-BP level, which in turn suppressed glycolysis and, ultimately, led to cell death. This study validates PFKFB3 as a target for new cancer therapies and provides a framework for future development efforts

Aryl hydrocarbon exposure induces expression of MMP-9 in human prostate cancer cell lines

Although aromatic hydrocarbons have been extensively studied with regard to tumor formation, there has been little investigation into effects of these environmental chemicals on regulation of genes involved in tumor invasion. We investigated effects of three arylhydrocarbons on expression of MMP-9 in PC-3 and DU145 human prostate cancer cells. TCDD exposure lead to dose and time dependent increases in MMP-9 expression. Benzo(a)pyrene and a PAH-containing soot (BDS) also induced this MMP. These hydrocarbons also stimulated MMP-9 protein secretion. Our data demonstrate that aryl hydrocarbons can stimulate the production of MMP-9 in human prostate cancer cells