Study of post-translational modifications of p53 in multiple myeloma

TP53 gene alterations remain one of the major determinants of poor prognosis in multiple myeloma (MM). However, p53 dysfunction can also arise through non-genetic mechanisms, like post-translational modifications (PTMs). Indeed, phosphorylation and acetylation play essential roles in modulating p53 stability and activity, but their functional relevance in primary MM samples has not been systematically explored. Here, we quantified the expression of four key p53 PTMs, phosphorylation at S15, S20, and T55, and acetylation at K382, using capillary nanoimmunoassay, in 127 newly diagnosed MM patients. We also evaluated the DNA damage marker γ-H2AX, the kinase Chk2, and the phosphatases PP1A and PP2A-C. We found that p53 PTM expression was highly heterogeneous among patients. p-p53 T55 and Ac-p53 K382 were the most frequently expressed, detected in more than 70% of samples. Patients with double-hit TP53 showed significantly lower p-p53 S20 and p-p53 T55 levels compared with those with normal TP53. Low p53 phosphorylation at S20, S15 and T55 was correlated with higher progression risk (HR = 2.39, p = 0.02; HR = 2.14, p = 0.04; and HR = 2.13, p = 0.005, respectively). We also identified deregulated expression of Chk2 and phosphatases, suggesting upstream regulatory imbalances. This is the first study to quantify p53 PTMs in a large set of MM patients, revealing that post-translational dysregulation contributes to p53 impairment independently of TP53 gene alterations. Characterizing p53 PTMs sheds light on the mechanisms underlying its dysfunction, particularly in patients with an intact TP53 gene, but dysfunctional p53 protein regulation.

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Journal
Blood Cancer Journal
Published
2026-07-17
DOI
https://doi.org/10.1038/s41408-026-01568-x
Primary Topic
Cancer-related Molecular Pathways
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article
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article

Study of post-translational modifications of p53 in multiple myeloma

Luís A. Corchete, Elizabeta A. Rojas, Laura Rosiñol, Juan José Lahuerta et al.
Blood Cancer Journal
Cancer-related Molecular Pathways
article

Study of post-translational modifications of p53 in multiple myeloma

Luís A. Corchete, Elizabeta A. Rojas, Laura Rosiñol, Juan José Lahuerta, Jesús F. San Miguel, Irena Misiewicz-Krzemińska, Isabel Isidro, María‐Victoria Mateos, Joaquín Martínez‐López, David Becerro-Recio, Norma C. Gutiérrez, Albert Oriol, Myriam Cuadrado, Sara Cristobal‐Vargas, Cristina de Ramón
article en

Abstract

TP53 gene alterations remain one of the major determinants of poor prognosis in multiple myeloma (MM). However, p53 dysfunction can also arise through non-genetic mechanisms, like post-translational modifications (PTMs). Indeed, phosphorylation and acetylation play essential roles in modulating p53 stability and activity, but their functional relevance in primary MM samples has not been systematically explored. Here, we quantified the expression of four key p53 PTMs, phosphorylation at S15, S20, and T55, and acetylation at K382, using capillary nanoimmunoassay, in 127 newly diagnosed MM patients. We also evaluated the DNA damage marker γ-H2AX, the kinase Chk2, and the phosphatases PP1A and PP2A-C. We found that p53 PTM expression was highly heterogeneous among patients. p-p53 T55 and Ac-p53 K382 were the most frequently expressed, detected in more than 70% of samples. Patients with double-hit TP53 showed significantly lower p-p53 S20 and p-p53 T55 levels compared with those with normal TP53. Low p53 phosphorylation at S20, S15 and T55 was correlated with higher progression risk (HR = 2.39, p = 0.02; HR = 2.14, p = 0.04; and HR = 2.13, p = 0.005, respectively). We also identified deregulated expression of Chk2 and phosphatases, suggesting upstream regulatory imbalances. This is the first study to quantify p53 PTMs in a large set of MM patients, revealing that post-translational dysregulation contributes to p53 impairment independently of TP53 gene alterations. Characterizing p53 PTMs sheds light on the mechanisms underlying its dysfunction, particularly in patients with an intact TP53 gene, but dysfunctional p53 protein regulation.

Blood Cancer Journal
Universidad Complutense de Madrid (ES), Universidad de Salamanca (ES), Research Institute Hospital 12 de Octubre (ES), Spanish National Cancer Research Centre (ES), Instytut Hematologii i Transfuzjologi (PL), Navarre Institute of Health Research (ES), Instituto de Investigación Biomédica de Salamanca (ES), Clinica Universidad de Navarra (ES), Centro de Investigación del Cáncer (ES), Hospital Universitari Germans Trias i Pujol (ES), Spanish Ovarian Cancer Research Group (ES), Centro de Investigación Biomédica en Red de Cáncer (ES), Consorci Institut D'Investigacions Biomediques August Pi I Sunyer (ES)
Amgen, Bristol-Myers Squibb, Sanofi, Celgene, BeiGene, European Commission, Sociedad Española de Hematología y Hemoterapia, Junta de Castilla y León, Instituto de Salud Carlos III, Cilag
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Cancer-related Molecular Pathways
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