Myc (c-Myc) counteracts p27 effects, and low p27 usually correlates with high Myc expression in human cancer. However there is no information on the co-expression of both genes in chronic lymphocytic leukemia (CLL). We found a lack of correlation between RNA and protein levels of p27 and Myc in CLL cells, so we determined the protein levels by immunoblot in 107 cases of CLL. We observed a high ...

-The abnormal proliferation of vascular smooth muscle cells (VSMCs) plays an important role in atherosclerosis and restenosis. Although several studies have implicated the growth inhibitory protein p27(Kip1) (p27) in the control of myocyte growth and hypertrophy, little is known about the molecular mechanisms that regulate p27 expression in the cardiovascular system. In the present study, we de...

During development, control of proliferation of neuronal precursor cells plays a crucial role in determining the number of neurons. Proliferation is driven by mitogens, but how it is terminated remains a mystery. In this study, we examined the role of cyclin-dependent kinase inhibitors in the control of proliferation of cerebellar granule cell precursors (GCPs). Among the inhibitors we examined...

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 ...

PURPOSE To examine the expression of the p27(KIP1)in the normal and epithelial-scraped cornea and whether degradation of p27(KIP1)by Skp2 is involved in the regulation of cell proliferation in response to wounding of the corneal epithelium. METHODS C57Bl6, p27(KIP1-/-), Skp2(-/-), and Skp2(-/-)/p27(KIP1-/-) double-knockout mice were examined. Normal and epithelial-scraped corneas were analyze...

PURPOSE AND EXPERIMENTAL DESIGN The prognosis for intrahepatic cholangiocarcinoma (ICC) depends mainly on the feasibility of complete surgical resection. In the absence of demonstrated biological predictors of survival, we evaluated the prognostic value of the cyclin-dependent kinase inhibitor p27 by immunohistochemistry in a series of routine specimens from 47 ICC patients, 22 with the hilar a...

Hepatocytes rarely proliferate in the healthy adult liver. We explored the roles of the cyclin kinase inhibitors p21 and p27 in maintaining hepatocyte quiescence. p27 is expressed throughout the wild-type liver, but the related protein p21 was not detected. However, p21 was detected in livers of p27-deficient mice. Increased p21 protein levels did not result from an increase in p21 mRNA express...

Nasopharyngeal carcinoma (NPC) is an Epstein-Barr virus-associated malignancy most common in East Asia and Africa. Aberrant expression of Jab1/CSN5, a negative regulator of the cell-cycle inhibitor p27, is correlated with reduced p27 expression and associated with advanced tumor stage and poor prognosis in several human cancers. In this study, we examined the functional relationship between Jab...

p27(Kip1) levels increase in many cells as they leave the cell cycle and begin to differentiate. The increase in p27(Kip1) levels generally precedes the expression of differentiation-specific genes. Previous studies from our laboratory showed that the overexpression of p27(Kip1) enhances myelin basic protein (MBP) promoter activity. This activation is specific to p27(Kip1). Additionally, inhibi...

OBJECTIVE We investigated whether the inhibitory effect of the immunosuppressant everolimus (RAD001) on vascular smooth muscle cell (VSMC) proliferation is mediated by p27/kip1 gene promoter activity. METHODS In this experimental study, cultured rat VSMCs were transiently transfected with a recombinant plasmid (pXp27) containing p27/kip1 gene promoter sequence and a chloramphenicol acetyltran...