Ravinder Kodela - JS-K, a nitric oxide-releasing prodrug, modulates ß-catenin/TCF signaling in leukemic Jurkat cells: evidence of an S-nitrosylated mechanism.

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      Biochem Pharmacol. 2010 Dec   1;80(11):1641-9. Epub 2010 Aug 24.


      β-Catenin is a central player of the Wnt signaling pathway that   regulates cell-cell adhesion and may promote leukemia cell   proliferation. We examined whether JS-K, an NO-donating prodrug,   modulates the Wnt/β-catenin/TCF-4 signaling pathway in Jurkat   T-Acute Lymphoblastic Leukemia cells. JS-K inhibited Jurkat T   cell growth in a concentration and time-dependent manner. The   IC(50)s for cell growth inhibition were 14±0.7 and 9±1.2μM at 24   and 48h, respectively. Treatment of the cells with JS-K for 24h,   caused a dose-dependent increase in apoptosis from 16±3.3% at   10μM to 74.8±2% at 100μM and a decrease in proliferation. This   growth inhibition was also due, in part, to alterations in the   different phases of the cell cycle. JS-K exhibited a   dose-dependent cytotoxicity as measured by LDH release at 24h.   However, between 2 and 8h, LDH release was less than 20% for any   indicated JS-K concentration. The β-catenin/TCF-4 transcriptional   inhibitory activity was reduced by 32±8, 63±5, and 93±2% at 2,   10, and 25μM JS-K, respectively, based on luciferase reporter   assays. JS-K reduced nuclear β-catenin and cyclin D1 protein   levels, but cytosolic β-catenin expression did not change. Based   on a time-course assay of S-nitrosylation of proteins by a biotin   switch assay, S-nitrsolyation of nuclear β-catenin was determined   to precede its degradation. A comparison of the S-nitrosylated   nuclear β-catenin to the total nuclear β-catenin showed that   β-catenin protein levels were degraded at 24h, while   S-nitrosylation of β-catenin occurred earlier at 0-6h. The NO   scavenger PTIO abrogated the JS-K mediated degradation of   β-catenin demonstrating the need for NO.

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