QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Xu, D. Articles by Juliano, R. L. Search for Related Content PubMed PubMed Citation Articles by Xu, D. Articles by Juliano, R. L.

P53-Dependent Cell-Killing by Selective Repression of Thymidine Kinase and Reduced Prodrug Activation

Department of Pharmacology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina

Selective killing of tumor cells is an important goal for cancer therapeutics. The tumor suppressor transcription factor p53 is absent or mutated in more than 50% of human tumors. Thus, determining approaches that use p53 status to regulate therapy may be an important strategy for attaining cancer selectivity. We have shown previously that a designed transcriptional repressor, K2–5F, strongly and selectively reduces the expression of its target gene MDR1. In this study, we exploited p53 status and the strong repressor activity of K2–5F to establish a system for preferential killing of p53-negative cells. In this system, the expression of K2–5F is induced by p53 in normal cells, and the K2–5F repressor then inhibits the expression of herpes simplex virus thymidine kinase (HSV-TK) driven by an MDR1 minipromoter. In p53-deficient cells, little K2–5F is expressed, and thus HSV-TK is expressed, allowing the cells to be killed by ganciclovir (GCV). K2–5F induced by exogenous p53 dramatically reduced the expression of HSV-TK in human embryonic kidney 293 cells, and it subsequently increased cell survival in response to GCV. To further evaluate this approach in a uniform genetic background, we developed Saos-2 cells stably expressing physiological levels of p53 and paired them with wild-type p53-negative Saos-2 cells. Stable expression of moderate levels of p53 in Saos-2 cells was able to induce the expression of K2–5F and reduce HSV-TK expression and resulted in a modest but distinct protection from GCV toxicity. Thus, this system may be suitable for further development as an approach to selective cancer therapy.

Address correspondence to: Dr. Rudy L. Juliano, Department of Pharmacology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599. E-mail: arjay{at}med.unc.edu

This article has been cited by other articles:

				V. Dixit and R. L. Juliano Selective Killing of Smad4-Negative Tumor Cells via a Designed Repressor Strategy Mol. Pharmacol., July 1, 2008; 74(1): 289 - 297. [Abstract] [Full Text] [PDF]

				Y.-L. Hsu, C.-Y. Cho, P.-L. Kuo, Y.-T. Huang, and C.-C. Lin Plumbagin (5-Hydroxy-2-methyl-1,4-naphthoquinone) Induces Apoptosis and Cell Cycle Arrest in A549 Cells through p53 Accumulation via c-Jun NH2-Terminal Kinase-Mediated Phosphorylation at Serine 15 in Vitro and in Vivo J. Pharmacol. Exp. Ther., August 1, 2006; 318(2): 484 - 494. [Abstract] [Full Text] [PDF]