title: DNA alkylation-induced phosphorylation of p53 and activation of kinases in colon cancer cells.
abstract: In response to DNA damage, p53 protein transiently stabilizes and accumulates in the nucleus, where it performs its role as a transcription factor. Phosphorylation of p53 increases its sequence-specific DNA-binding activity. In the present study, we have examined the effect of methylmethane sulfonate (MMS) to HCT-116 human colon cancer cells on the phosphorylation of p53. Results show that p53 protein becomes phosphorylated at serine 15 (Ser15) and Ser392 residues after treatment with MMS in a time-dependent manner. Increased levels of phospho-p53(Ser15) and phospho-p53(Ser392) were maintained up to 50 h of the MMS treatment. We also examined the involvement of probable kinase(s), which could be responsible for MMS-induced phosphorylation of p53 at Ser15 and Ser392. In vitro phosphorylation assay, carried out with the immunoprecipates of MMS-treated cells, showed an increased phosphorylation of p53 by c-Jun kinase 1 (JNK1) at early time points (2.5 h). However, with cyclin-dependent kinase (Cdk2) and TFIIH complex associated kinase CAK, the phosphorylation of p53 was increased at later time points (25 h). The phosphorylation of p53 by Cdc2 and MAPK (p38) kinases remained unaffected in the MMS-treated versus untreated cells. The MMS-induced phosphorylation of p53 correlates with our previous findings of p53's ability for increased sequence-specific DNA-binding and transcriptional activity in the cells treated with DNA alkylating agents.
authors.affiliation: UF Shands Cancer Center and Department of Anatomy and Cell Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA.
authors.forename: A S
authors.initials: AS
authors.lastname: Jaiswal
authors.forename: S
authors.initials: S
authors.lastname: Narayan
mesh_terms: D000478:Alkylation; D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology; D015153:Blotting, Western; D042846:CDC2-CDC28 Kinases; D003110:Colonic Neoplasms / Q000378:metabolism*; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D004273:DNA, Neoplasm / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D051758:Transcription Factor TFIIH; D014157:Transcription Factors / Q000378:metabolism; D019473:Transcription Factors, TFII; D014407:Tumor Cells, Cultured / Q000187:drug effects; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D018906:Antineoplastic Agents, Alkylating; D004273:DNA, Neoplasm; D014157:Transcription Factors; D019473:Transcription Factors, TFII; D016159:Tumor Suppressor Protein p53; D051758:Transcription Factor TFIIH; D008741:Methyl Methanesulfonate; D005982:Glutathione Transferase; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases