Single chain antibody against the common epitope of mutant p53 restores wild-type activity to mutant p53 protein

Human wild-type and mutant p53 genes were expressed under the control of a galactose-inducible promoter in Saccharomyces cerevisiae. The growth rate of the yeast was reduced in cells expressing wild-type p53, whereas cells transformed with mutant p53 genes derived from human tumors were less affected. Coexpression of the normal p53 protein with the human cell cycle-regulated protein kinase CDC2Hs resulted in much more pronounced growth inhibition that for p53 alone. Cells expressing p53 and CDC2Hs were partially arrested in G1, as determined by morphological analysis and flow cytometry. p53 was phosphorylated when expressed in the yeast, but differences in phosphorylation did not explain the growth inhibition attributable to coexpression of p53 and CDC2Hs. These results suggest that wild-type p53 has a growth-inhibitory activity in S. cerevisiae similar to that observed in mammalian cells and suggests that this yeast may provide a useful model for defining the pathways through which p53 acts.

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The mdm-2 oncogene can overcome wild-type p53 suppression of transformed cell growth

Molecular and Cellular Biology ◽

10.1128/mcb.13.1.301-306.1993 ◽

1993 ◽

Vol 13 (1) ◽

pp. 301-306 ◽

Cited By ~ 1

Author(s):

C A Finlay

Keyword(s):

P53 Protein ◽

Mutant P53 ◽

Wild Type ◽

Rat Embryo ◽

Ras Gene ◽

Double Minute ◽

Murine Double Minute ◽

Low Levels ◽

Wild Type P53 ◽

P53 Genes

Expression of a p53-associated protein, Mdm-2 (murine double minute-2), can inhibit p53-mediated transactivation. In this study, overexpression of the Mdm-2 protein was found to result in the immortalization of primary rat embryo fibroblasts (REFs) and, in conjunction with an activated ras gene, in the transformation of REFs. The effect of wild-type p53 on the transforming properties of mdm-2 was determined by transfecting REFs with ras, mdm-2, and normal p53 genes. Transfection with ras plus mdm-2 plus wild-type p53 resulted in a 50% reduction in the number of transformed foci (relative to the level for ras plus mdm-2); however, more than half (9 of 17) of the cell lines derived from these foci expressed low levels of a murine p53 protein with the characteristics of a wild-type p53. These results are in contrast to previous studies which demonstrated that even minimal levels of wild-type p53 are not tolerated in cells transformed by ras plus myc, E1A, or mutant p53. The mdm-2 oncogene can overcome the previously demonstrated growth-suppressive properties of p53.

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TRRAP is essential for regulating the accumulation of mutant and wild-type p53 in lymphoma

Blood ◽

10.1182/blood-2017-09-806679 ◽

2018 ◽

Vol 131 (25) ◽

pp. 2789-2802 ◽

Cited By ~ 9

Author(s):

Alexander Jethwa ◽

Mikołaj Słabicki ◽

Jennifer Hüllein ◽

Marius Jentzsch ◽

Vineet Dalal ◽

...

Keyword(s):

Protein Stability ◽

P53 Protein ◽

Mutant P53 ◽

Wild Type ◽

Therapeutic Targeting ◽

Key Points ◽

Wild Type P53

Key Points The HAT complex member TRRAP is vital for maintaining high p53 levels by shielding it against the natural p53 degradation machinery. Acetylation-modifying complexes regulate p53 protein stability, which may provide a basis for therapeutic targeting of mutant p53.

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CP-31398 Restores DNA-binding Activity to Mutant p53in Vitrobut Does Not Affect p53 Homologs p63 and p73

Journal of Biological Chemistry ◽

10.1074/jbc.m401854200 ◽

2004 ◽

Vol 279 (44) ◽

pp. 45887-45896 ◽

Cited By ~ 45

Author(s):

Mark J. Demma ◽

Serena Wong ◽

Eugene Maxwell ◽

Bimalendu Dasmahapatra

Keyword(s):

Dna Binding ◽

Mammalian Cells ◽

P53 Protein ◽

Binding Activity ◽

Mutant P53 ◽

Dependent Manner ◽

Wild Type ◽

Dna Binding Activity

The p53 protein plays a major role in the maintenance of genome stability in mammalian cells. Mutations of p53 occur in over 50% of all cancers and are indicative of highly aggressive cancers that are hard to treat. Recently, there has been a high degree of interest in therapeutic approaches to restore growth suppression functions to mutant p53. Several compounds have been reported to restore wild type function to mutant p53. One such compound, CP-31398, has been shown effectivein vivo, but questions have arisen to whether it actually affects p53. Here we show that mutant p53, isolated from cells treated with CP-31398, is capable of binding to p53 response elementsin vitro. We also show the compound restores DNA-binding activity to mutant p53 in cells as determined by a chromatin immunoprecipitation assay. In addition, using purified p53 core domain from two different hotspot mutants (R273H and R249S), we show that CP-31398 can restore DNA-binding activity in a dose-dependent manner. Using a quantitative DNA binding assay, we also show that CP-31398 increases significantly the amount of mutant p53 that binds to cognate DNA (Bmax) and its affinity (Kd) for DNA. The compound, however, does not affect the affinity (Kdvalue) of wild type p53 for DNA and only increasesBmaxslightly. In a similar assay PRIMA1 does not have any effect on p53 core DNA-binding activity. We also show that CP-31398 had no effect on the DNA-binding activity of p53 homologs p63 and p73.

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Mutant p53 tumor suppressor alleles release ras-induced cell cycle growth arrest.

Molecular and Cellular Biology ◽

10.1128/mcb.11.3.1344 ◽

1991 ◽

Vol 11 (3) ◽

pp. 1344-1352 ◽

Cited By ~ 34

Author(s):

G G Hicks ◽

S E Egan ◽

A H Greenberg ◽

M Mowat

Keyword(s):

Cell Cycle ◽

Tumor Suppressor ◽

Growth Regulation ◽

Growth Arrest ◽

Mutant P53 ◽

Wild Type ◽

Type Activity ◽

Wild Type P53 ◽

Negative Growth ◽

P53 Genes

Overexpression of an activated ras gene in the rat embryo fibroblast line REF52 results in growth arrest at either the G1/S or G2/M boundary of the cell cycle. Both the DNA tumor virus proteins simian virus 40 large T antigen and adenovirus 5 E1a are able to rescue ras induced lethality and cooperate with ras to fully transform REF52 cells. In this report, we present evidence that the wild-type activity of the tumor suppressor gene p53 is involved in the negative growth regulation of this model system. p53 genes encoding either a p53Val-135 or p53Pro-193 mutation express a highly stable p53 protein with a conformation-dependent loss of wild-type activity and the ability to eliminate any endogenous wild-type p53 activity in a dominant negative manner. In cotransfection assays, these mutant p53 genes are able to rescue REF52 cells from ras-induced growth arrest, resulting in established cell lines which express elevated levels of the ras oncoprotein and show morphological transformation. Full transformation, as assayed by tumor formation in nude mice, is found only in the p53Pro-193-plus-ras transfectants. These cells express higher levels of the ras protein than do the p53Val-135-plus-ras-transfected cells. Transfection of REF52 cells with ras alone or a full-length genomic wild-type p53 plus ras results in growth arrest and lethality. Therefore, the selective event for p53 inactivation or loss during tumor progression may be to overcome a cell cycle restriction induced by oncogene overexpression (ras). These results suggest that a normal function of p53 may be to mediate negative growth regulation in response to ras or other proliferative inducing signals.

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Effect of new olivacine derivatives on p53 protein level

Pharmacological Reports ◽

10.1007/s43440-019-00004-1 ◽

2020 ◽

Vol 72 (1) ◽

pp. 214-224 ◽

Cited By ~ 2

Author(s):

Tomasz Gębarowski ◽

Benita Wiatrak ◽

Katarzyna Gębczak ◽

Beata Tylińska ◽

Kazimierz Gąsiorowski

Keyword(s):

Anticancer Activity ◽

P53 Protein ◽

Mutant P53 ◽

Wild Type ◽

Suppressor Activity ◽

Essential Function ◽

Mutant Cells ◽

New Anticancer Drugs ◽

Glycoprotein Inhibition ◽

P21 Proteins

Abstract Background The p53 protein is a transcription factor for many genes, including genes involved in inhibiting cell proliferation and inducing apoptosis in genotoxically damaged and tumor-transformed cells. In more than 55% of cases of human cancers, loss of the essential function of p53 protein is found. In numerous reports, it has been shown that small molecules (chemical compounds) can restore the suppressor function of the mutant p53 protein in tumor cells. The aim of this study was to evaluate the potential anticancer activity of three newly synthesized olivacine derivatives. Methods The study was performed using two cell lines—CCRF/CEM (containing the mutant p53 protein) and A549 (containing a non-mutant, wild-type p53 protein). The cells were incubated with olivacine derivatives for 18 h and then assays were carried out: measurement of the amount of p53 and p21 proteins, detection of apoptosis, cell cycle analysis, and rhodamine 123 accumulation assay (evaluation of P-glycoprotein inhibition). Multiple-criteria decision analysis was used to compare the anticancer activity of the tested compounds. Results Each tested compound caused the reconstitution of suppressor activity of the p53 protein in cells with the mutant protein. In addition, one of the compounds showed significant antitumor activity in both wild-type and mutant cells. For all compounds, a stronger effect on the level of the p53 protein was observed than for the reference compound—ellipticine. Conclusions The observed effects of the tested new olivacine derivatives (pyridocarbazoles) suggest that they are good candidates for new anticancer drugs.

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