Journal of Cell Science, Vol 111, Issue 9 1185-1196, Copyright © 1998 by Company of Biologists

JOURNAL ARTICLES

Up-regulation of p27Kip1, p21WAF1/Cip1 and p16Ink4a is associated with, but not sufficient for, induction of squamous differentiation

BL Harvat, A Wang, P Seth and AM Jetten
Cell Biology Section, Laboratory of Pulmonary Pathobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.

Irreversible growth arrest is an early and integral part of squamous cell differentiation in normal human epidermal keratinocytes (NHEKs) and is assumed to be linked to the control of expression of differentiation-specific genes. In this study, we examine the link between the molecular events associated with growth arrest and the expression of differentiation genes. NHEKs that have been induced to undergo growth arrest and differentiation by suspension culture contain populations in both G1 and G2/M of the cell cycle. The irreversible growth arrest state in NHEKs is characterized by an accumulation of the hypophosphorylated forms of Rb and p130, with subsequent down-regulation of levels of Rb, up-regulation of p130 and associated down-regulation of E2F-regulated genes such as cyclin A. These events correlate with an inhibition of G1 cdk activity, mediated in part by an increase in the cdk inhibitors p21(WAF1/Cip1), p27(Kip1) and p16(Ink4a). Flow cytometric and immunoblot analysis demonstrated that the timing of the up-regulation of p27, p16 and p130 corresponds closely with the induction of the squamous-specific genes cornifin alpha (SPRR-1) and transglutaminase type I, suggesting a close link between control of growth arrest and differentiation. However, growth arrest induced by over-expression of p27, p21 or p16 by recombinant adenovirus is not sufficient to induce expression of the differentiation genes, or to invoke the pattern of cell cycle regulatory protein expression characteristic of the differentiation-specific irreversible growth arrest. We conclude that growth arrest mediated by activation of the Rb pathway is not sufficient to trigger terminal squamous differentiation and additional signals which can be generated during suspension culture are required to promote the complete differentiation program.

This article has been cited by other articles:

				H. Robitaille, R. Proulx, K. Robitaille, R. Blouin, and L. Germain The Mitogen-activated Protein Kinase Kinase Kinase Dual Leucine Zipper-bearing Kinase (DLK) Acts as a Key Regulator of Keratinocyte Terminal Differentiation J. Biol. Chem., April 1, 2005; 280(13): 12732 - 12741. [Abstract] [Full Text] [PDF]

				W. C. Weinberg and M. F. Denning P21WAF1 CONTROL OF EPITHELIAL CELL CYCLE AND CELL FATE Crit. Rev. Oral. Biol. Med., November 1, 2002; 13(6): 453 - 464. [Abstract] [Full Text] [PDF]

				S. Chandrasekharan, T. H. Qiu, N. Alkharouf, K. Brantley, J. B. Mitchell, and E. T. Liu Characterization of Mice Deficient in the Src Family Nonreceptor Tyrosine Kinase Frk/rak Mol. Cell. Biol., July 15, 2002; 22(14): 5235 - 5247. [Abstract] [Full Text] [PDF]

				H.-D. Beer, C. Munding, N. Dubois, C. Mamie, D. Hohl, and S. Werner The Estrogen-responsive B Box Protein. A NOVEL REGULATOR OF KERATINOCYTE DIFFERENTIATION J. Biol. Chem., May 31, 2002; 277(23): 20740 - 20749. [Abstract] [Full Text] [PDF]

				J. M. Paramio, C. Segrelles, S. Ruiz, J. Martin-Caballero, A. Page, J. Martinez, M. Serrano, and J. L. Jorcano The ink4a/arf Tumor Suppressors Cooperate with p21cip1/waf in the Processes of Mouse Epidermal Differentiation, Senescence, and Carcinogenesis J. Biol. Chem., November 16, 2001; 276(47): 44203 - 44211. [Abstract] [Full Text] [PDF]

				T. K. Said, R. C. B. Moraes, U. Singh, F. S. Kittrell, and D. Medina Cyclin-dependent Kinase (cdk) Inhibitors/cdk4/cdk2 Complexes in Early Stages of Mouse Mammary Preneoplasia Cell Growth Differ., June 1, 2001; 12(6): 285 - 295. [Abstract] [Full Text] [PDF]

				A. Quaroni, J. Q. Tian, P. Seth, and C. Ap Rhys p27Kip1 is an inducer of intestinal epithelial cell differentiation Am J Physiol Cell Physiol, October 1, 2000; 279(4): C1045 - C1057. [Abstract] [Full Text] [PDF]

				Q. M. Wang, R. Feinman, F. Kashanchi, J. M. Houghton, G. P. Studzinski, and L. E. Harrison Changes in E2F Binding after Phenylbutyrate-induced Differentiation of Caco-2 Colon Cancer Cells Clin. Cancer Res., July 1, 2000; 6(7): 2951 - 2958. [Abstract] [Full Text]

				D. G. Farwell, K. A. Shera, J. I. Koop, G. A. Bonnet, C. P. Matthews, G. W. Reuther, M. D. Coltrera, J. K. McDougall, and A. J. Klingelhutz Genetic and Epigenetic Changes in Human Epithelial Cells Immortalized by Telomerase Am. J. Pathol., May 1, 2000; 156(5): 1537 - 1547. [Abstract] [Full Text] [PDF]

				J. A. Raleigh, S.-C. Chou, D. P. Calkins-Adams, C. A. Ballenger, D. B. Novotny, and M. A. Varia A Clinical Study of Hypoxia and Metallothionein Protein Expression in Squamous Cell Carcinomas Clin. Cancer Res., March 1, 2000; 6(3): 855 - 862. [Abstract] [Full Text]

				Y. Kadowaki, T. Fujiwara, T. Fukazawa, J. Shao, T. Yasuda, T. Itoshima, S. Kagawa, L. G. Hudson, J. A. Roth, and N. Tanaka Induction of Differentiation-dependent Apoptosis in Human Esophageal Squamous Cell Carcinoma by Adenovirus-mediated p21sdi1 Gene Transfer Clin. Cancer Res., December 1, 1999; 5(12): 4233 - 4241. [Abstract] [Full Text] [PDF]

				V. Chaturvedi, J.-Z. Qin, M. F. Denning, D. Choubey, M. O. Diaz, and B. J. Nickoloff Apoptosis in Proliferating, Senescent, and Immortalized Keratinocytes J. Biol. Chem., August 13, 1999; 274(33): 23358 - 23367. [Abstract] [Full Text] [PDF]

				H. Drissi, D. Hushka, F. Aslam, Q. Nguyen, E. Buffone, A. Koff, A. J. van Wijnen, J. B. Lian, J. L. Stein, and G. S. Stein The Cell Cycle Regulator p27kip1 Contributes to Growth and Differentiation of Osteoblasts Cancer Res., August 1, 1999; 59(15): 3705 - 3711. [Abstract] [Full Text] [PDF]

				W. C. Weinberg, E. Fernandez-Salas, D. L. Morgan, A. Shalizi, E. Mirosh, E. Stanulis, C. Deng, H. Hennings, and S. H. Yuspa Genetic Deletion of p21WAF1 Enhances Papilloma Formation but not Malignant Conversion in Experimental Mouse Skin Carcinogenesis Cancer Res., May 1, 1999; 59(9): 2050 - 2054. [Abstract] [Full Text] [PDF]

				T. U. Ha, D. L. Segev, D. Barbie, P. T. Masiakos, T. T. Tran, D. Dombkowski, M. Glander, T. R. Clarke, H. K. Lorenzo, P. K. Donahoe, et al. Mullerian Inhibiting Substance Inhibits Ovarian Cell Growth through an Rb-independent Mechanism J. Biol. Chem., November 17, 2000; 275(47): 37101 - 37109. [Abstract] [Full Text] [PDF]