SODIUM-BUTYRATE INHIBITS EXPRESSION OF UROKINASE AND ITS RECEPTOR MESSENGER-RNAS AT BOTH TRANSCRIPTION AND POST-TRANSCRIPTION LEVELS IN COLON-CANCER CELLS

The effects of butyrate on the modulation of urokinase plasminogen act ivator (uPA) and its receptor (uPAR) mRNAs were studied, While both mR NA levels were increased after stimulation by tumor necrosis factor al pha (TNF alpha), phorbol ester (PMA) and cycloheximide, they were inhi bited by butyrate at 2.5 to 25 mM. Nuclear run-on transcription assays indicated that uPA mRNA was modulated by butyrate at the transcriptio nal level but the uPAR gene was regulated at both transcriptional and post-transcriptional levels in the presence or absence of TNF alpha. I n the presence of PMA, however, butyrate acts at the posttranscription al level on both genes.