DU145 human prostate carcinoma invasiveness is modulated by urokinase receptor (uPAR) downstream of epidermal growth factor receptor (EGFR) signaling.
Tumor cell motility and invasion have been linked to upregulated signaling from both the epidermal growth factor receptor (EGFR) and that for urokinase-type plasminogen activator (uPAR). However, we do not know whether these events are interdependent or unrelated, despite the obvious diagnostic and therapeutic implications. Gene microarray analyses have suggested that EGFR signaling via phospholipase C-gamma (PLCgamma) induces uPAR transcription. We utilized two sublines of the DU145 human prostate carcinoma cell line that are genetically engineered to differentially activate the EGFR/PLCgamma cascade and are variously invasive in vitro and in vivo. uPAR protein levels in these cells were found to be dependent on PLC signaling, pharmacologic inhibition of PLC signaling reduced uPAR expression. To determine whether uPAR was a required element in EGFR-mediated invasion, we stably expressed uPAR cDNA in either sense or antisense orientation in the two DU145 sublines. Interestingly, uPA production was modulated in parallel, although to a lesser degree, with uPAR in these sublines. Antisense to uPAR significantly restricted invasion of the highly invasive DU145 WT cells through Matrigel and reduced aggressiveness of tumors in nude mice. Up-regulation of uPAR significantly increased the invasiveness of the moderately invasive DU145 parental (DU145 P) cells through Matrigel, but this increased invasiveness was not seen in mice. uPA activity appears to contribute to invasiveness at least through Matrigel, as antibody to uPA or amiloride limited the transmigration. These results support a model of tumor invasion promoted by autocrine EGFR signaling involving reinforcing altered gene expression, of uPAR at least, that further induces cell motility. Herein, a number of key molecules whose expression levels are interrelated, including both EGFR and uPAR, are required but none are sufficient in the absence of other keys molecules in promoting tumor progression.
Department of Pathology, University of Pittsburgh, PA 15261, USA.
Asmaa
A
Mamoune
Jareer
J
Kassis
Sourabh
S
Kharait
Susanne
S
Kloeker
Elisabeth
E
Manos
David A
DA
Jones
Alan
A
Wells
D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D016375:Antisense Elements (Genetics) / Q000494:pharmacology; D019898:Autocrine Communication / Q000235:genetics; D002277:Carcinoma / Q000235:genetics / Q000378:metabolism*; D002465:Cell Movement / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D004815:Epidermal Growth Factor / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009361:Neoplasm Invasiveness / Q000235:genetics*; D051966:Phospholipase C gamma; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D055293:Receptors, Urokinase Plasminogen Activator; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism; D015854:Up-Regulation / Q000235:genetics; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
D016375:Antisense Elements (Genetics); D018076:DNA, Complementary; C524898:PLAUR protein, human; C524899:Plaur protein, mouse; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D004815:Epidermal Growth Factor; D000584:Amiloride; D066246:ErbB Receptors; D010738:Type C Phospholipases; D051966:Phospholipase C gamma; D014568:Urokinase-Type Plasminogen Activator