title: [The role of p21 (wafl/cip1) in human colorectal carcinoma cell apoptosis].
abstract: OBJECTIVE
  To investigate the role of basal expression p21 and stress-stimulated p21 in preventing apoptosis of human colorectal carcinoma cells DLD1 after treatment of adriamycin, roentgenotherapy and gene therapy of p53.
  
  
  METHODS
  A human colorectal carcinoma cell line DLD1 whose p21 expression can be controlled by isopropyl-beta-D-thiogalactoside (IPTG) was established. The morphology, DNA fragmentation and survival rates of two kinds of DLD1 cells expressing or not expressing p21 were observed after treatment with adriamycin, X-ray and transient transfection of p53. The cells in S stage were incubated with [3H] thymidine so as to examine the relationship between apoptosis and cell cycle.
  
  
  RESULTS
  (1) p21 may be one of the most important stress-stimulated proteins in the cells, which can be induced by the p53-dependent pathway and the p53-independent pathway as well. (2) Basal expression of p21 plays an important antiapoptosis role in carcinoma cells after stress-treatment. In contrast, stress-stimulated p21 plays a minor role in preventing apoptosis.
  
  
  CONCLUSIONS
  Basal expression of p21 plays a more important antiapoptosis role than stress-stimulated p21 in carcinoma cells.
authors.affiliation: Shanghai Celstar Bio-phamnaceutical, Shanghai 200050, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Lu
authors.forename: W
authors.initials: W
authors.lastname: Cao
mesh_terms: D017209:Apoptosis; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics*; D006801:Humans; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
chemical_list: D050759:Cyclin-Dependent Kinase Inhibitor p21; D016159:Tumor Suppressor Protein p53