This Article Full Text Full Text (PDF) Alert me when this article is cited 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 Facchinetti, M. M. Articles by Senderowicz, A. M. Search for Related Content PubMed PubMed Citation Articles by Facchinetti, M. M. Articles by Senderowicz, A. M.

UCN-01-Induced Cell Cycle Arrest Requires the Transcriptional Induction of p21^waf1/cip1 by Activation of Mitogen-Activated Protein/Extracellular Signal-Regulated Kinase Kinase/Extracellular Signal-Regulated Kinase Pathway

Molecular Therapeutics Unit, Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, NIH, Bethesda, Maryland

The small molecule UCN-01 is a cyclin-dependent kinase (CDK) modulator shown to have antiproliferative effects against several in vitro and in vivo cancer models currently being tested in human clinical trials. Although UCN-01 may inhibit several serine-threonine kinases, the exact mechanism by which it promotes cell cycle arrest is still unclear. We have reported previously that UCN-01 promotes G₁-S cell cycle arrest in a battery of head and neck squamous cancer cell lines. The arrest is accompanied by an increase in both p21^waf1/cip1 and p27^kip1 CDK inhibitors leading to loss in G₁ CDK activity. In this report, we explore the role and the mechanism for the induction of these endogenous CDK inhibitors. We observed that p21 was required for the cell cycle effects of UCN-01, as HCT116 lacking p21 (HCT116 p21^–/–) was refractory to the cell cycle effects of UCN-01. Moreover, UCN-01 promoted the accumulation of p21 at the mRNA level in the p53-deficient HaCaT cells without increase in the p21 mRNA half-life, suggesting that UCN-01 induced p21 at the transcriptional level. To study UCN-01 transcriptional activation of p21, we used several p21^waf1/cip1 promoter-driven luciferase reporter plasmids and observed that UCN-01 activated the full-length p21^waf1/cip1 promoter and a construct lacking p53 binding sites. The minimal promoter region required for UCN-01 (from –110 bp to the transcription start site) was the same minimal p21^waf1/cip1 promoter region required for Ras enhancement of p21^waf1/cip1 transcription. Neither protein kinase C nor PDK1/AKT pathways were relevant for the induction of p21 by UCN-01. In contrast, the activation of mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK)/extracellular signal-regulated kinase mitogen-activated protein kinase pathways was required for p21 induction as UCN-01 activated this pathway, and genetic or chemical MEK inhibitors blunted p21 accumulation. These results demonstrated for the first time that p21 is required for UCN-01 cell cycle arrest. Moreover, we showed that the accumulation of p21 is transcriptional via activation of the MEK pathway. This novel mechanism, by which UCN-01 exerts its antiproliferative effect, represents a promising strategy to be exploited in future clinical trials.

This article has been cited by other articles:

				J. L. Oliva, M. C. Caino, A. M. Senderowicz, and M. G. Kazanietz S-Phase-specific Activation of PKC{alpha} Induces Senescence in Non-small Cell Lung Cancer Cells J. Biol. Chem., February 29, 2008; 283(9): 5466 - 5476. [Abstract] [Full Text] [PDF]

				K. Selvendiran, L. Tong, S. Vishwanath, A. Bratasz, N. J. Trigg, V. K. Kutala, K. Hideg, and P. Kuppusamy EF24 Induces G2/M Arrest and Apoptosis in Cisplatin-resistant Human Ovarian Cancer Cells by Increasing PTEN Expression J. Biol. Chem., September 28, 2007; 282(39): 28609 - 28618. [Abstract] [Full Text] [PDF]

				Y. Tu, W. Wu, T. Wu, Z. Cao, R. Wilkins, B.-H. Toh, M. E. Cooper, and Z. Chai Antiproliferative Autoantigen CDA1 Transcriptionally Up-regulates p21Waf1/Cip1 by Activating p53 and MEK/ERK1/2 MAPK Pathways J. Biol. Chem., April 20, 2007; 282(16): 11722 - 11731. [Abstract] [Full Text] [PDF]

				X.-Y. Pei, W. Li, Y. Dai, P. Dent, and S. Grant Dissecting the Roles of Checkpoint Kinase 1/CDC2 and Mitogen-Activated Protein Kinase Kinase 1/2/Extracellular Signal-Regulated Kinase 1/2 in Relation to 7-Hydroxystaurosporine-Induced Apoptosis in Human Multiple Myeloma Cells Mol. Pharmacol., December 1, 2006; 70(6): 1965 - 1973. [Abstract] [Full Text] [PDF]

				A. Calcabrini, J. M. Garcia-Martinez, L. Gonzalez, M. J. Tendero, M. T. A. Ortuno, P. Crateri, A. Lopez-Rivas, G. Arancia, P. Gonzalez-Porque, and J. Martin-Perez Inhibition of proliferation and induction of apoptosis in human breast cancer cells by lauryl gallate Carcinogenesis, August 1, 2006; 27(8): 1699 - 1712. [Abstract] [Full Text] [PDF]

				Q. Ren, C. Kari, M. R.D. Quadros, R. Burd, P. McCue, A. P. Dicker, and U. Rodeck Malignant Transformation of Immortalized HaCaT Keratinocytes through Deregulated Nuclear Factor {kappa}B Signaling. Cancer Res., May 15, 2006; 66(10): 5209 - 5215. [Abstract] [Full Text] [PDF]

				S. Shukla and S. Gupta Molecular targets for apigenin-induced cell cycle arrest and apoptosis in prostate cancer cell xenograft. Mol. Cancer Ther., April 1, 2006; 5(4): 843 - 852. [Abstract] [Full Text] [PDF]

				J. Turner, C. Koumenis, T. E. Kute, R. P. Planalp, M. W. Brechbiel, D. Beardsley, B. Cody, K. D. Brown, F. M. Torti, and S. V. Torti Tachpyridine, a metal chelator, induces G2 cell-cycle arrest, activates checkpoint kinases, and sensitizes cells to ionizing radiation Blood, November 1, 2005; 106(9): 3191 - 3199. [Abstract] [Full Text] [PDF]

				M. F. Aguero, M. M. Facchinetti, Z. Sheleg, and A. M. Senderowicz Phenoxodiol, a Novel Isoflavone, Induces G1 Arrest by Specific Loss in Cyclin-Dependent Kinase 2 Activity by p53-Independent Induction of p21WAF1/CIP1 Cancer Res., April 15, 2005; 65(8): 3364 - 3373. [Abstract] [Full Text] [PDF]

				M. Katsuki, V. T. G. Chuang, K. Nishi, K. Kawahara, H. Nakayama, N. Yamaotsu, S. Hirono, and M. Otagiri Use of Photoaffinity Labeling and Site-directed Mutagenesis for Identification of the Key Residue Responsible for Extraordinarily High Affinity Binding of UCN-01 in Human {alpha}1-Acid Glycoprotein J. Biol. Chem., January 14, 2005; 280(2): 1384 - 1391. [Abstract] [Full Text] [PDF]