title: p21Cip/WAF1 activation is an important factor for the ERK pathway dependent anti-proliferation of colorectal cancer cells.
abstract: p21Cip/WAF1, an important regulator of cell proliferation, is induced by both p53- and extracellular signal regulated kinase (ERK) pathways. The induction of p21Cip/WAF1 occurs by prolonged activation of the ERKs caused by extracellular stimuli, such as zinc. However, not all the cells appeared to respond to ERK pathway dependent p21Cip/WAF1 induction. Here we investigated the cause of such difference using colorectal cancer cells. p21Cip/WAF1 induction and concomitant reduction of bromodeoxyuridine (BrdU) incorporation were observed by zinc treatment within HT-29 and DLD-1. However, HCT-116 cells with high endogenous p21Cip/WAF1 levels did not show any additional increment of p21Cip/WAF1 levels by zinc treatment and did maintain high BrdU incorporation level. The p21Cip/WAF1 induction by zinc depended upon prolonged activation of extracellular signal regulated kinase (ERK) was not observed in HCT-116 cells. The percentage of BrdU positive cells was 50% higher in p21Cip/WAF1 -/- HCT-116 cells compared to p21Cip/WAF1 +/+ HCT- 116 cells, and no cells induced p21Cip/WAF1 incorporated BrdU in its nucleus, yet confirming the importance of p21Cip/WAF1 induction in anti- proliferation. These results again support that p21Cip/WAF1 induction is a determinant in the regulation of colonic proliferation by the ERK pathway.
authors.affiliation: Department of Biotechnology, Yonsei University, Seoul 120-752, Korea.
authors.forename: Ki Sook
authors.initials: KS
authors.lastname: Park
authors.forename: Soung Hoo
authors.initials: SH
authors.lastname: Jeon
authors.forename: Jong Won
authors.initials: JW
authors.lastname: Oh
authors.forename: Kang Yell
authors.initials: KY
authors.lastname: Choi
mesh_terms: D001973:Bromodeoxyuridine / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D015179:Colorectal Neoplasms / Q000201:enzymology / Q000378:metabolism*; D050759:Cyclin-Dependent Kinase Inhibitor p21; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism / Q000502:physiology*; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D015032:Zinc / Q000494:pharmacology
chemical_list: C493956:CDKN1A protein, human; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D005419:Flavonoids; D047428:Protein Kinase Inhibitors; D048049:Extracellular Signal-Regulated MAP Kinases; D001973:Bromodeoxyuridine; D015032:Zinc; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one