title: [The effect of the tumor suppressor p53 and its mutant forms on the differentiation and viability of K562 leukemic cells].
abstract: Mutations of the p53 tumor suppressor are often observed in various human malignancies including blast crisis of chronic myelogenous leukaemia (CML). The pattern of p53 mutation in CML shows some peculiarities as compared with the majority of other neoplasias. In particular, the substitutions at codon 273, one of the most common p53 alteration in various tumors, are not characteristic of CML. To test whether distinction in the pattern of p53 mutation are associated with certain peculiarities of biological effects of different mutant proteins in myeloid cells, we obtained and analysed a panel of human K562 cell sublines expressing various exogenous p53: human Pro156, His175, His194, Trp248 and His 273, or murine temperature-sensitive (ts) Val135 that has properties of mutant protein at 37 degrees C, but shows activities of wild-type (wt) p53 at 32 degrees C. We have found that expression of wt-p53 enhanced the dependence of cells on growth/survival factors, incubation of sparse (< 10(5) cells per/ml) K562/Val135 cultures at 32 degrees C caused apoptosis. In media conditioned by cells of different origin (K562, colorectal carcinoma LIM 1215, Rat1 fibroblast) the p53-dependent apoptosis was inhibited. In conditions that do not lead to apoptosis, the expression of ts-wt-p53 was accompanied by dramatic increase in the number of cells containing glycophorin A (GlycPhA) and "antigen of erythroblasts"--specific markers of erythroid differentiation. Unlike the wt-p53, the majority of tumor-derived mutant p53 (Pro156, His175, His194, Trp248) increased cells survival in media with low serum content and decreased the number of cell expressing GlycPhA, CD9, CD15 and CD71 differentiation antigens. On the other hand, expression of His273-p53 caused a significant augmentation in the number of CD9-positive cells and enhanced the dependence on growth/survival factors that are present in serum or conditioned media. The data obtained are consistent with the idea that unusual pattern of p53 mutations in CML can reflect the peculiarities of the effects of some mutant proteins on differentiation and/or viability of leukemic cells.
authors.forename: O S
authors.initials: OS
authors.lastname: Kremenetskaia
authors.forename: N P
authors.initials: NP
authors.lastname: Logacheva
authors.forename: A Iu
authors.initials: AIu
authors.lastname: Baryshnikov
authors.forename: P M
authors.initials: PM
authors.lastname: Chumakov
authors.forename: B P
authors.initials: BP
authors.lastname: Kopnin
mesh_terms: D002455:Cell Division / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D002471:Cell Transformation, Neoplastic / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology*; D016147:Genes, Tumor Suppressor / Q000502:physiology*; D006801:Humans; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics* / Q000473:pathology; D009154:Mutation / Q000502:physiology*; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000235:genetics* / Q000502:physiology
chemical_list: D016159:Tumor Suppressor Protein p53
vernacular_title: Vliianie opukholevogo supressora p53 i ego mutantnykh form na differentsirovku i zhiznesposobnost' leĭkoznykh kletok K562.