Abstract
Abstract
Mantle cell lymphoma (MCL) is characterized by a clinically aggressive course with frequent relapses and poor survival. The p53 pathway is frequently dysregulated and p53 status predicts clinical outcome in MCL. Diclofenac has been reported to increase p53 pathway activity, upregulates p73 expression and inhibit cell growth; hence we investigated the ability of diclofenac to induce apoptosis and/or cell cycle arrest in MCL, and its dependence on p53 status. To investigate the response of MCL to diclofenac, wild-type p53 [Granta-519 and JVM-2] and mutant p53 [Jeko-1 and Mino-1] expressing cells, therapy resistant cell lines and primary human cells isolated from MCL patients were used. Cell proliferation, apopotosis, and expression of down-stream signaling p53 targets were analyzed. Nontoxic concentrations of diclofenac induced concentration- and duration-dependent inhibition of MCL cell growth independent of p53 status. Diclofenac treatment also resulted in cell cycle arrest and cell death. Molecularly, diclofenac treatment was associated with increased activity of caspases 3, 7, and 8. Increased p53 pathway activity was demonstrated by duration-dependent induction of p53 transcriptional target genes, including the cell cycle regulatory molecule p21 and pro-apoptotic molecules including, PUMA, NOXA, BIM, and CD95. Most importantly, diclofenac treatment was associated with enhanced expression of the pro-apoptotic isoforms of the p53 homologue TAp73. Our data demonstrates that diclofenac treatment results in decreased cell cycle progression, and increased apoptosis that is associated with increased p53 pathway activity, independent of p53 status, and increased activity of its family member p73.
Citation Format: Hesham M. Hassan, Michelle L. Varney, Aalia M. Aly, Shantaram S. Joshi, Rakesh K. Singh, Bhavana J. Dave. The COX inhibitor, diclofenac induces mantle cell lymphoma apoptosis independent of p53 status. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2632. doi:10.1158/1538-7445.AM2015-2632