conclusions despite the fact that abnormalities in p53 and p27kip1 may be involved in the development of oscc, their clinical significance in the studied population seems limited. further investigation on the combined p53/p27kip1 expression may be helpful in predicting the biologic behavior of this tumor. results p53 and p27kip1 expression were found in 28.57% (8 positive versus 20 negative) an...

The mitogen-activated protein kinases (MAPKs) extracellular signal-regulated protein kinase (ERK)1 and ERK2, involved in regulating cell growth and differentiation, are constitutively active in A375 and WM239 human melanoma cells. Using PD098059, an inhibitor of MAPK kinase (MEK), we investigated the role of persistently activated ERK1/2 in cell growth. The inhibition of MAPK activity induced a...

We investigated the status and the regulation of the CDK inhibitor p27 in a choroidal melanoma tumour derived cell line (OCM-1). By contrast to normal choroidal melanocytes, the expression level of p27 was low in these cells and the MAP kinase pathway was constitutively activated. Genetic or chemical inhibition of this pathway induced p27 accumulation, while MAP kinase reactivation triggered a ...

Angiotensin II enhances the development of atherosclerotic lesion in which cellular proliferation and/or migration are critical steps. Although cyclin-dependent kinase inhibitor, p27, and Rho/Rho-kinase pathway have recently been implicated as factors regulating these events cooperatively, their role in vivo has not been fully elucidated. We evaluated the contribution of p27 and Rho-kinase to a...

The molecular basis of the antagonism between cellular proliferation and differentiation is poorly understood. We have investigated the role of the cyclin-dependent kinase inhibitor p27(Xic1) in the co-ordination of cell cycle exit and differentiation during early myogenesis in vivo using Xenopus embryos. In this report, we demonstrate that p27(Xic1) is highly expressed in the developing myotom...

The cyclin-dependent kinase (cdk) inhibitor p27 is a central mediator in the imposition and maintenance of quiescence through the sequestration of G1-specific cyclin-cdk complexes. Previous studies have implicated the c-Jun co-activator protein Jab1 as a regulator of intracellular p27 levels. Jab1 has been reported to interact with p27 and cause its translocation to the cytoplasm as a prelude t...

The p27(Kip1) protein is a cyclin-dependent kinase inhibitor that blocks cell division in response to antimitogenic cues. p27 expression is reduced in many human cancers, and p27 functions as a tumor suppressor that exhibits haploinsufficiency in mice. Despite the well characterized role of p27 as a cyclin-dependent kinase inhibitor, its mechanism of tumor suppression is unknown. We used Molone...

Proliferation and apoptosis are increased in many types of inflammatory diseases. A role for the cyclin kinase inhibitor p27(Kip1) (p27) in limiting proliferation has been shown. In this study, we show that p27(-/-) mesangial cells and fibroblasts have strikingly elevated rates of apoptosis, not proliferation, when deprived of growth factors. Apoptosis was rescued by restoration of p27 expressi...

The cyclin-dependent kinase inhibitor p27(KIP1) is a tumor suppressor gene in mice, and loss of p27 protein is a negative prognostic indicator in human cancers. Unlike other tumor suppressors, the p27 gene is rarely mutated in tumors. Therefore misregulation of p27, rather than loss of the gene, is responsible for tumor-associated decreases in p27 protein levels. We performed a functional genom...