Following activation of p53, for example by viral infection or induction of DNA damage, p21 expression is upregulated. High levels of p21 then result in RB-E2F complex formation and downregulation of a large number of cell cycle genes. Thus, p53-dependent transcriptional repression is indirect.

Collectively, our findings demonstrate that p21, in conjunction with pRb, plays a central role in regulating multiple epithelial processes and orchestrating specific tumor suppressor functions. The pocket protein family (pRb, p107 and p130) plays unique and overlapping roles in differentiation and cell cycle control (1).

Here, we analyze the functions of p21 and pRB in the regulation of G1 and in the coupling of extracellular signals with the cell cycle. We have studied the role of p21 and pRB using mouse embryo fibroblasts (MEFs) that are deficient for these genes.

p21Sdi1/WAF1/Cip1 inhibits cyclin-dependent protein kinases and cell proliferation. p21 is presumed to inhibit growth by preventing the phosphorylation of growth-regulatory proteins, including the retinoblastoma tumor suppressor protein (pRb).

In 11 cases of p21 positive immunostaining, there was lymph node metastasis (pN1) in 9 (81.8%). Conclusions: These results suggest that abnormalities of p16 protein may be closely associated with the carcinogenesis or cell proliferation of esophageal cancers.

Our results confirm that a large number of NSCLC have a low level of p21 expression. The associations of p21 and nuclear cyclin D1, pRb, p16INK4a support the relevance of pathways linked to lung carcinogenesis that involve p21 but may act in addition to direct CDK inhibition.

Remarkably, pRbDEpi;p21 / mice show an acute skin inflammatory phenotype and develop spontaneous epithelial tumors, particularly affecting tongue and oral tissues. Biochemical analyses and...

Mar 31, 2022 · In the current synopsis, the mechanism of regulation by p53-p21-RB signaling is assessed and the overlap with p53-p21-DREAM signaling is examined. The tumor suppressor p53 can induce cell...

Jun 12, 2017 · Here, we show that the CDK inhibitor p21 (CDKN 1A) maintains the viability of DNA damage‐induced senescent cells. Upon p21 knockdown, senescent cells acquired multiple DNA lesions that activated ataxia telangiectasia mutated (ATM) and nuclear factor (NF)‐κB kinase, leading to decreased cell survival.

Oct 14, 2013 · Remarkably, pRb ΔEpi;p21−/− mice show an acute skin inflammatory phenotype and develop spontaneous epithelial tumors, particularly affecting tongue and oral tissues. Biochemical analyses and...