The subgranular zone (SGZ) of the dentate gyrus of the hippocampus is a brain region where robust neurogenesis continues throughout adulthood. Cyclin-dependent kinases (CDKs) have a primary role in controlling cell division and cellular proliferation. p21(Cip1) (p21) is a CDK inhibitor that restrains cell cycle progression. Confocal microscopy revealed that p21 is abundantly expressed in the nu...

In this study we used adenovirus vector-mediated transduction of either the p53 gene (rAd-p53) or the p21(WAF1/CIP1) gene (rAd-p21) to mimic both p53-dependent and -independent up-regulation of p21(WAF1/CIP1) within a human ovarian cancer cell line, 2774, and the derivative cell lines, 2774qw1 and 2774qw2. We observed that rAd-p53 can induce apoptosis in both 2774 and 2774qw1 cells but not in 2...

Differential positioning of the histone variant H2A.Z in a p53 dependent manner was shown to regulate p21 transcription. Whether H2A.Z is involved in p21 activity in the absence of p53 is not known. The p21 gene is repressed in estrogen receptor (ER) negative cell lines that are p53-/- and hormone independent for their growth. Here we demonstrate that class I and II pan Histone deacetylase inhi...

When suspended in methylcellulose, primary mouse keratinocytes cease proliferation and differentiate. Suspension also reduces the activity of the cyclin-dependent kinase cdk2, an important cell cycle regulatory enzyme. To determine how suspension modulates these events, we examined its effects on wild-type keratinocytes and keratinocytes nullizygous for the cdk2 inhibitor p21(Cip1). After suspe...

The proteins p53 and p21 are important components that regulate G1-S transition through the cell cycle. We immunohistochemically investigated p53 and p21 expression in 111 patients with esophageal squamous cell carcinoma. We also evaluated whether the expression of either of these proteins is a prognostic factor according to the p53-dependent and -independent pathways. The positive rates of p53...

BACKGROUND P21 is one kind of cyclin-dependent kinase inhibitor that can prevent cells from going through the G1/S phase checkpoint and inhibit cell proliferation. Proliferative vitreoretinopathy (PVR) is a proliferative response in the eye. The aim of this study was to determine whether p21Waf1/Cip1 (p21) suppresses the proliferation and migration of retinal pigment epithelial (RPE) cells in v...

p21 loss has been implicated in conferring oncogenic activity to known tumor suppressor gene KLF4 and cancer drug tamoxifen. Regulators of p21, therefore, play critical roles in tumorigenesis. Here, we report that X-linked tumor suppressor FOXP3 is essential for p21 expression in normal epithelia and that lack of FOXP3 is associated with p21 down-regulation in breast cancer samples. A specific ...

Oncoprotein MDM2 inhibits p53-dependent cell cycle arrest and apoptosis. MDM2-overexpressing human cancer cell lines (n = 3) were found to be resistant to growth inhibition after infection by p53-expressing adenovirus (Ad-p53), as compared to low MDM2-expressing tumors (n = 3), in vitro. The growth of MDM2-overexpressing tumors, however, was inhibited by p21-expressing adenovirus (Ad-p21) infec...

Introduction: Proliferation of cancer cells and the potential of metastasis depend on the activity of different biomarkers such as proliferative ones. Proliferative biomarkers including ki-67, cyclin E1, cyclin D1, p27, and p21 were analyzed through immunohistochemistry (IHC) in previous studies. Methods: The current study aimed at investigating the utilizing role of RT-PCR in studying prolife...

An antibody (anti-p21ser) was raised against a ras p21-related synthetic peptide and was able to recognize specifically the substitution of serine for glycine at amino acid 12 of p21. This substitution causes oncogenic activation of p21. Anti-p21ser was found to immunoprecipitate v-Ki-ras p21 and to strongly inhibit its ability to autophosphorylate and to bind GTP in an immunoabsorption assay. ...