Rescue of embryonic stem cells from cellular transformation by proteomic stabilization of mutant p53 and conversion into WT conformation.
p53 is a well-known tumor suppressor that is mutated in over 50% of human cancers. These mutations were shown to exhibit gain of oncogenic function compared with the deletion of the gene. Additionally, p53 has fundamental roles in differentiation and development; nevertheless, mutant p53 mice are viable and develop malignant tumors only on adulthood. We set out to reveal the mechanisms by which embryos are protected from mutant p53-induced transformation using ES cells (ESCs) that express a conformational mutant of p53. We found that, despite harboring mutant p53, the ESCs remain pluripotent and benign and have relatively normal karyotype compared with ESCs knocked out for p53. Additionally, using high-content RNA sequencing, we show that p53 is transcriptionally active in response to DNA damage in mutant ESCs and elevates p53 target genes, such as p21 and btg2. We also show that the conformation of mutant p53 protein in ESCs is stabilized to a WT conformation. Through MS-based interactome analyses, we identified a network of proteins, including the CCT complex, USP7, Aurora kinase, Nedd4, and Trim24, that bind mutant p53 and may shift its conformation to a WT form. We propose this conformational shift as a novel mechanism of maintenance of genomic integrity, despite p53 mutation. Harnessing the ability of these protein interactors to transform the oncogenic mutant p53 to the tumor suppressor WT form can be the basis for future development of p53-targeted cancer therapy.
Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel; and.
Noa
N
Rivlin
Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
Shir
S
Katz
Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel; and.
Maayan
M
Doody
Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel; and.
Michal
M
Sheffer
Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel; and.
Stav
S
Horesh
Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel; and.
Alina
A
Molchadsky
Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel; and.
Gabriela
G
Koifman
Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel; and.
Yoav
Y
Shetzer
Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel; and.
Naomi
N
Goldfinger
Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel; and varda.rotter@weizmann.ac.il geiger@post.tau.ac.il.
Varda
V
Rotter
Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel varda.rotter@weizmann.ac.il geiger@post.tau.ac.il.
Tamar
T
Geiger
D000230:Adenocarcinoma; D000818:Animals; D001943:Breast Neoplasms; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D047108:Embryonic Development / Q000235:genetics; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000502:physiology; D018398:Homeodomain Proteins / Q000235:genetics; D006801:Humans; D016864:Li-Fraumeni Syndrome / Q000235:genetics* / Q000378:metabolism; D019656:Loss of Heterozygosity / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D000071317:Nanog Homeobox Protein; D011487:Protein Conformation; D040901:Proteomics; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism
D018398:Homeodomain Proteins; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53