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1.
Curr Res Struct Biol ; 7: 100133, 2024.
Article in English | MEDLINE | ID: mdl-38435052

ABSTRACT

Liquid-liquid phase separation plays a crucial role in cellular physiology, as it leads to the formation of membrane-less organelles in response to various internal stimuli, contributing to various cellular functions. However, the influence of exogenous stimuli on this process in the context of disease intervention remains unexplored. In this current investigation, we explore the impact of doxorubicin on the abnormal self-assembly of p53 using a combination of biophysical and imaging techniques. Additionally, we shed light on the potential mechanisms behind chemoresistance in cancer cells carrying mutant p53. Our findings reveal that doxorubicin co-localizes with both wild-type p53 (WTp53) and its mutant variants. Our in vitro experiments indicate that doxorubicin interacts with the N-terminal-deleted form of WTp53 (WTp53ΔNterm), inducing liquid-liquid phase separation, ultimately leading to protein aggregation. Notably, the p53 variants at the R273 position exhibit a propensity for phase separation even in the absence of doxorubicin, highlighting the destabilizing effects of point mutations at this position. The strong interaction between doxorubicin and p53 variants, along with its localization within the protein condensates, provides a potential explanation for the development of chemotherapy resistance. Collectively, our cellular and in vitro studies emphasize the role of exogenous agents in driving phase separation-mediated p53 aggregation.

3.
Int J Mol Sci ; 25(2)2024 Jan 17.
Article in English | MEDLINE | ID: mdl-38256221

ABSTRACT

Cutaneous squamous cell carcinomas in kidney-transplant recipients are frequent, with an increasing incidence linked to long immunosuppression durations and exposure to ultraviolet radiation. p53 is at the cornerstone of ultraviolet-induced DNA damage, but the role of p53 post-translational modifications in this context is not yet deciphered. Here, we investigated the phosphorylation status of p53 at Serine 392 in 25 cutaneous squamous cell carcinomas in kidney-transplant recipients, compared with 22 non-transplanted patients. Cutaneous squamous cell carcinomas in transplanted patients occurred after a median period of 19 years of immunosuppression, with a median number of 15 cutaneous squamous cell carcinomas and more aggressive histological and clinical characteristics. There was no significant difference between Ki67, p53, and pSer392p53 expression in the two groups. Using principal component analysis, we identified a cluster of exclusively transplanted patients with a median of 23 years of immunosuppression duration, significantly more aggressive biological characteristics, and higher pSer392p53 expression. pSer392p53 was expressed in the whole tumor, suggesting an early carcinogenic event in the course of prolonged immunosuppression. This high, diffuse pSer392p53 expression, corresponding to a high level of DNA damage, might be useful to identify aggressive cutaneous squamous cell carcinomas in kidney-transplant recipients to treat them more aggressively.


Subject(s)
Carcinoma, Squamous Cell , Transplant Recipients , Humans , Tumor Suppressor Protein p53/genetics , Ultraviolet Rays , Carcinoma, Squamous Cell/genetics , Kidney
4.
J Inorg Biochem ; 251: 112433, 2024 02.
Article in English | MEDLINE | ID: mdl-38043136

ABSTRACT

The p53 protein plays a major role in cancer prevention, and over 50% of cancer diagnoses can be attributed to p53 malfunction. p53 incorporates a structural Zn site that is required for proper protein folding and function, and in many cases point mutations can result in loss of the Zn2+ ion, destabilization of the tertiary structure, and eventual amyloid aggregation. Herein, we report a series of compounds designed to act as small molecule stabilizers of mutant p53, and feature Zn-binding fragments to chaperone Zn2+ to the metal depleted site and restore wild-type (WT) function. Many Zn metallochaperones (ZMCs) have been shown to generate intracellular reactive oxygen species (ROS), likely by chelating redox-active metals such as Fe2+/3+ and Cu+/2+ and undergoing associated Fenton chemistry. High levels of ROS can result in off-target effects and general toxicity, and thus, careful tuning of ligand Zn2+ affinity, in comparison to the affinity for other endogenous metals, is important for selective mutant p53 targeting. In this work we show that by using carboxylate donors in place of pyridine we can change the relative Zn2+/Cu2+ binding ability in a series of ligands, and we investigate the impact of donor group changes on metallochaperone activity and overall cytotoxicity in two mutant p53 cancer cell lines (NUGC3 and SKGT2).


Subject(s)
Metallochaperones , Tumor Suppressor Protein p53 , Zinc , Humans , Cell Line, Tumor , Chelating Agents , Metallochaperones/chemistry , Reactive Oxygen Species/metabolism , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , Zinc/metabolism , Protein Binding
5.
Article in English | MEDLINE | ID: mdl-37691512

ABSTRACT

BACKGROUND: The pathogenesis of post-traumatic stress disorder (PTSD) triggered by high-voltage electrical burn (HVEB) remains unclear and the oxidative stress plays a role in this process. The purpose of this study is to investigate the underlying mechanism of oxidative stress mediates hippocampal neuronal apoptosis in rats with PTSD triggered by HVEB. MATERIALS AND METHODS: The PTSD rat model was developed by stimulating with high voltage electricity and screened using behavioral performance including Morris water maze (MWM), elevated plus-maze (EPM) and open-field test (OFT). The reactive oxygen species (ROS) generation was measured by DHE fluorescence staining or flow cytometry. Western blotting assay was used to detect the proteins of p-JNK, JNK, P53, PUMA, Bcl-2 and Bax in hippocampal tissue or HT22 cells treated with electrical stimulation. RESULTS: The serum MDA and 8-OHdG levels were increased (P < 0.001), while the activities of SOD and CAT were decreased (P < 0.001) significantly in patients with HVEB. Behavioral test results showed that high-voltage electric stimulation induced the PTSD-like symptoms and the ROS-JNK-P53 pathway was involved in the neuronal apoptosis in rats with PTSD induced by HVEB. In vitro experiments further confirmed the electrical stimulation induced neuronal apoptosis through ROS/JNK/P53 signaling pathway and the antioxidant NAC could rescued the ROS generation, activation of JNK/P53 proteins and improved the cell apoptosis rate in HT22 cells. Finally, the JNK inhibitor SP600125 could significantly inhibited the percentage of HT22 cell apoptosis induced by electrical stimulation (P < 0.001). CONCLUSIONS: These results indicated that oxidative stress mediates hippocampal neuronal apoptosis through ROS/JNK/P53 pathway in rats with PTSD triggered by HVEB.

6.
J Biomol Struct Dyn ; : 1-17, 2023 Sep 03.
Article in English | MEDLINE | ID: mdl-37661778

ABSTRACT

SIRT1 is a protein associated with vital cell functions such as gene regulation, metabolism, ageing, and cellular energy restoration. Its association with the tumor suppressor protein p53 is essential for controlling the growth of cells, apoptosis, and response to DNA damage. By raising p53 acetylation, encouraging apoptosis, and reducing cell proliferation, inhibiting SIRT1's catalytic domain, which interacts with p53, shows potential as a cancer treatment. The aim of the study is to find compounds that could inhibit SIRT1 and thus lower the proliferation of cancer cells. Employing molecular docking techniques, a virtual screening of ∼900 compounds (isolated from medicinal plants and derivatives) gave us 13 active compounds with good binding affinity. Additional evaluation of pharmacokinetic and pharmacodynamic properties led to the selection of eight compounds with desirable properties. Docking analysis confirmed stable interactions between the final eight compounds (C1-C8) and the SIRT1 catalytic domain. Molecular dynamics simulations show overall stability and moderate changes in protein structure upon compound binding. The compactness of the protein indicated the protein's tight packing upon the inhibitors binding. Binding free energy calculations revealed that compounds C2 (-49.96 ± 0.073 kcal/mol and C1 (-44.79 ± 0.077 kcal/mol) exhibited the highest energy, indicating strong binding affinity to the SIRT1 catalytic domain. These compounds, along with C8, C5, C6, C3, C4 and C7, showed promising potential as SIRT1 inhibitors. Based on their ability to reduce SIRT1 activity and increase apoptosis, the eight chemicals discovered in this work may be useful in treating cancer.Communicated by Ramaswamy H. Sarma.

7.
Mikrochim Acta ; 190(4): 136, 2023 03 15.
Article in English | MEDLINE | ID: mdl-36920574

ABSTRACT

A poly(thiophene acetic acid)/Au/poly(methylene blue) nanostructured interface was electrochemically assembled step-by-step on screen-printed carbon electrodes (SPCE) for label-free detection of p53 protein. The initial electrical conductive properties of the polymeric interface were increased with an additional layer of poly(methylene blue) electropolymerized in the presence of gold nanoparticles. The nano-immunosensing architecture was prepared by covalent immobilization of anti-p53 antibodies as bioreceptors through the poly(thiophene acetic acid) moieties. The nano-immunosensor assembly was extensively characterized by ultraviolet-visible spectrophotometry, dynamic and electrophoretic light scattering, scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, atomic force microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. Under optimal conditions, p53 was specifically and selectively detected by square wave voltammetry in a linear range between 1 and 100 ng mL-1 with a limit of detection of 0.65 ng mL-1. In addition, the electrochemical nano-immunosensor detected p53 in spiked human serum samples and colorectal cancer cell lysates, and the results were validated with a standard spectrophotometric method using a paired samples t test, which did not exhibit significant differences between both methods. The resultant p53 nano-immunosensor is simple to assemble, robust, and has the potential for point-of-care biomarker detection applications.


Subject(s)
Acetic Acid , Metal Nanoparticles , Humans , Electrochemical Techniques/methods , Gold/chemistry , Metal Nanoparticles/chemistry , Methylene Blue , Thiophenes
8.
J Inorg Biochem ; 242: 112164, 2023 05.
Article in English | MEDLINE | ID: mdl-36871418

ABSTRACT

The p53 protein, known as the 'guardian of the genome', plays an important role in cancer prevention. Unfortunately, p53 mutations result in compromised activity with over 50% of cancers resulting from point mutations to p53. There is considerable interest in mutant p53 reactivation, with the development of small-molecule reactivators showing promise. We have focused our efforts on the common p53 mutation Y220C, which causes protein unfolding, aggregation, and can result in the loss of a structural Zn from the DNA-binding domain. In addition, the Y220C mutant creates a surface pocket that can be stabilized using small molecules. We previously reported the bifunctional ligand L5 as a Zn metallochaperone and reactivator of the p53-Y220C mutant. Herein we report two new ligands L5-P and L5-O that are designed to act as Zn metallochaperones and non-covalent binders in the Y220C mutant pocket. For L5-P the distance between the Zn-binding di-(2-picolyl)amine function and the pocket-binding diiodophenol was extended in comparison to L5, while for L5-O we extended the pocket-binding moiety via attachment of an alkyne function. While both new ligands displayed similar Zn-binding affinity to L5, neither acted as efficient Zn-metallochaperones. However, the new ligands exhibited significant cytotoxicity in the NCI-60 cell line screen as well as in the NUGC3 Y220C mutant cell line. We identified that the primary mode of cytotoxicity is likely reactive oxygen species (ROS) generation for L5-P and L5-O, in comparison to mutant p53 reactivation for L5, demonstrating that subtle changes to the ligand scaffold can change the toxicity pathway.


Subject(s)
Metallochaperones , Tumor Suppressor Protein p53 , Metallochaperones/metabolism , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , Ligands , Cell Line, Tumor , Protein Domains
9.
Biomolecules ; 13(2)2023 02 03.
Article in English | MEDLINE | ID: mdl-36830660

ABSTRACT

Benzodiazepines that consist of one α- and one ß-amino acid residues linked together in a seven-membered heterocyclic ring could be treated as small, rigid, cyclic dipeptides capable of exhibiting a wide range of biological activities. During our research on novel analogues of anthramycin, a tricyclic antibiotic benzodiazepine, we developed the synthesis of two benzodiazepine dimers, obtained through the cyclization of appropriate linear tripeptides. The synthesized compounds were tested on a panel of seven cancer and normal cell lines. The developed molecules exhibited promising cytotoxic activity against the lung cancer cell lines A549 and NCI-H1299 and the epidermoid carcinoma cell line A-431. Moreover, they showed significant selectivity compared to the reference cell lines (BJ-human normal skin fibroblasts and MRC-5-human normal lung cell line). When tested on two isogenic cell lines, HCT116 and HCT116p53-/- (colon cancer), contrary to cisplatin being used as a positive control, the obtained compounds showed a cytotoxic effect independent of the p53 protein status. For the above reasons, the obtained compounds can be considered a new group of promising anticancer agents, useful in the fight against p53-dependent drug resistance in cancers. They can also be treated as convenient, leading structures suitable for further optimization and searching for more active and selective molecules.


Subject(s)
Antineoplastic Agents , Lung Neoplasms , Humans , Tumor Suppressor Protein p53 , Benzodiazepines , Antineoplastic Agents/pharmacology , Drug Resistance , Peptides/pharmacology , Cell Line, Tumor , Cell Proliferation
10.
RNA ; 29(5): 630-643, 2023 05.
Article in English | MEDLINE | ID: mdl-36653114

ABSTRACT

p53 protein is a key regulator of cellular homeostasis by coordinating the framework of antiproliferative pathways as a response to various stress factors. Although the main mechanism of stress-dependent induction of p53 protein relies on post-translational modifications influencing its stability and activity, a growing amount of evidence suggests that complex regulation of p53 expression occurs also at the mRNA level. This study explores structural determinants of long-range RNA-RNA interactions in p53 mRNA, crucial for stress-dependent regulation of p53 protein translation. We demonstrate that the 8-nt bulge motif plays a key structural role in base-pairing of complementary sequences from the 5' and 3' untranslated regions of p53 mRNA. We also show that one of the p53 translation regulators, nucleolin, displays an RNA chaperone activity and facilitates the association of sequences involved in the formation of long-range interactions in p53 mRNA. Nucleolin promotes base-pairing of complementary sequences through the bulge motif, because mutations of this region reduce or inhibit pairing while compensatory mutations restore this interaction. Mutational analysis of nucleolin reveals that all four RNA recognition motifs are indispensable for optimal RNA chaperone activity of nucleolin. These observations help to decipher the unique mechanism of p53 protein translation regulation pointing to bulge motif and nucleolin as the critical factors during intramolecular RNA-RNA recognition in p53 mRNA.


Subject(s)
Phosphoproteins , Tumor Suppressor Protein p53 , Tumor Suppressor Protein p53/genetics , RNA, Messenger/metabolism , 3' Untranslated Regions , 5' Untranslated Regions/genetics , Nucleolin
11.
Bioact Mater ; 20: 404-417, 2023 Feb.
Article in English | MEDLINE | ID: mdl-35784636

ABSTRACT

Human cancers typically express a high level of tumor-promoting mutant p53 protein (Mutp53) with a minimal level of tumor-suppressing wild-type p53 protein (WTp53). In this regard, inducing Mutp53 degradation while activating WTp53 is a viable strategy for precise anti-tumor therapy. Herein, a new carrier-free nanoprodrug (i.e., Mn-ZnO2 nanoparticles) was developed for concurrent delivery of dual Zn-Mn ions and reactive oxygen species (ROS) within tumor to regulate the p53 protein for high anti-tumor efficacy. In response to the mild tumor acidic environment, the released Zn2+ and H2O2 from Mn-ZnO2 NPs induced ubiquitination-mediated proteasomal degradation of Mutp53, while the liberative Mn2+ and increased ROS level activated the ATM-p53-Bax pathway to elevate WTp53 level. Both in vitro and in vivo results demonstrated that pH-responsive decomposition of Mn-ZnO2 NPs could effectively elevate the intracellular dual Zn-Mn ions and ROS level and subsequently generate the cytotoxic hydroxyl radical (•OH) through the Fenton-like reaction. With the integration of multiple functions (i.e., carrier-free ion and ROS delivery, tumor accumulation, p53 protein modulation, toxic •OH generation, and pH-activated MRI contrast) in a single nanosystem, Mn-ZnO2 NPs demonstrate its superiority as a promising nanotherapeutics for p53-mutated tumor therapy.

12.
Mol Pharm ; 20(1): 680-689, 2023 01 02.
Article in English | MEDLINE | ID: mdl-36515396

ABSTRACT

Developing gene vectors with high transfection efficiency and low cytotoxicity to humans is crucial to improve gene therapy outcomes. This study set out to investigate the use of cationic polypeptide bilayer assemblies formed by coil-sheet poly(l-lysine)-block-poly(l-benzyl-cysteine) (PLL-b-PBLC) as gene vectors that present improved transfection efficiency, endosomal escape, and biocompatibility compared to PLL. The formation of the polyplexes was triggered by hydrogen bonding, hydrophobic interactions, and electrostatic association between the cationic PLL segments and the negatively charged plasmid encoding p53, resulting in self-assembled polypeptide chains. Transfection efficiency of these polyplexes increased with increments of PLL-to-PBLC block ratios, with PLL15-b-PBLC5 bilayers exhibiting the best in vitro transfection efficiency among all, suggesting that PLL-b-PBLC bilayer assemblies are efficient in the protection and stabilization of genes. The polypeptide bilayer gene vector reversed the cisplatin sensitivity of p53-null cancer cells by increasing apoptotic signaling. Consistent with in vitro results, mouse xenograft studies revealed that PLL15-b-PBLC5/plasmid encoding p53 therapy significantly suppressed tumor growth and enhanced low-dose cisplatin treatment, while extending survival of tumor-bearing mice and avoiding significant body weight loss. This study presents a feasible gene therapy that, combined with low-dose chemotherapeutic drugs, may treat genetically resistant cancers while reducing side effects in clinical patients.


Subject(s)
Cisplatin , Neoplasms , Humans , Animals , Mice , Tumor Suppressor Protein p53/genetics , Peptides/chemistry , Transfection , Genetic Therapy , Plasmids/genetics , Neoplasms/drug therapy , Neoplasms/genetics , Polylysine/chemistry
13.
Curr Opin Chem Biol ; 72: 102230, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36436275

ABSTRACT

The p53 protein plays a critical role in the prevention of genome mutations in the body, however, this protein is frequently mutated in cancer and almost all cancers exhibit malfunction along the p53 pathway. In addition to a loss of activity, mutant p53 protein is prone to unfolding and aggregation, eventually forming amyloid aggregates. There continues to be a considerable effort to develop strategies to restore normal p53 expression and activity and this review details recent advances in small-molecule stabilization of mutant p53 protein and the design of p53 aggregation inhibitors.


Subject(s)
Neoplasms , Tumor Suppressor Protein p53 , Humans , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , Protein Aggregates , Neoplasms/metabolism , Mutation , Amyloid
14.
Cancer Biomark ; 36(1): 1-16, 2023.
Article in English | MEDLINE | ID: mdl-35912730

ABSTRACT

BACKGROUND: LncRNA STK4 antisense RNA 1 (STK4-AS1) has been identified as a potential biomarker associated with multiple cancers. We proposed that STK4-AS1 plays a role in the proliferation of osteosarcoma by regulating the cell cycle. METHODS: We compared the expression of STK4-AS1, p53, and p21 in osteosarcoma vs normal samples in clinical tissues and cell lines. We determined the effect of overexpression and knockdown of STK4-AS1 in p53 expressing osteosarcoma cells U2OS, p53 muted osteosarcoma cells MG63, and osteoblast cells hFOB on p53 and p21 expression and the cell viability. For U2OS and MG63, the cell cycle was analyzed and the expression of cyclin proteins was determined. We overexpressed p53 or p21 in STK4-AS1 overexpressed cells to explore the association of STK4-AS1 and p53 in U2OS. RESULTS: The STK4-AS1 expression was higher and p53 and p21 expression were lower in osteosarcoma tissue and cells than in their non-cancer counterparts. The expression of STK4-AS1 was negatively correlated with the expression of p53 or p21. Knockdown of STK4-AS1 in U2OS decreased the cell viability, increased cells in the G0/G1 phase, decreased cells in the S and G2/M phase, decreased expression of cyclin A and B, increased p53 and p21, and had no effect on cyclin D and cyclin E, while overexpression of STK4-AS1 did the opposes. Overexpression of p53 or p21 recovered some changes caused by STK4-AS1 overexpression in U2OS. MG63 expressed no p53 and the expression of p21, cyclin A, and cyclin B, cell viability, and cell cycle were not affected by altered STK4-AS1 levels. In hFOB cells, the expression of p53 and p21 was decreased and the cell viability was increased when STK4-AS1 was overexpressed, but they were not affected when STK4-AS1 was knocked down. CONCLUSION: LncRNA STK4-AS1 promoted the cell cycle of osteosarcoma cells by inhibiting p53 expression.


Subject(s)
Bone Neoplasms , Osteosarcoma , RNA, Long Noncoding , Humans , RNA, Long Noncoding/metabolism , Cell Line, Tumor , Cell Proliferation/genetics , Apoptosis/genetics , Osteosarcoma/genetics , Osteosarcoma/metabolism , Bone Neoplasms/genetics , Bone Neoplasms/metabolism , RNA, Antisense/genetics , Gene Expression Regulation, Neoplastic , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , Intracellular Signaling Peptides and Proteins/genetics
15.
Journal of Modern Urology ; (12): 421-423, 2023.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-1006066

ABSTRACT

【Objective】 To investigate the expressions of P53 and Ki-67 in prostate cancer (PCa)and to explore their correlation with the clinicopathological characteristics. 【Methods】 The expressions of P53 and Ki-67 in 90 PCa patients were detected with immunohistochemistry. Patients’ age, preoperative prostate-specific antigen (PSA) level, postoperative Gleason score, pathological stage, and invasion of neurovascular cancer embolus of all patients were recorded. The relationship of P53 expression with the above indexes was evaluated. 【Results】 The positive rates of P53 and Ki-67 were 27.8% (25/90) and 46.7% (42/90), respectively. The positive rate of P53 in pT2 and pT3-T4 stage groups were 19.7% (13/66) and 50.0% (12/24) (P=0.005), and the positive rate of Ki-67 were 36.4% (24/66) and 75.0% (18/24) (P=0.001), respectively. The positive rate of Ki-67 in Gleason score ≤6, ≤7 and ≥8 groups were 30.4%, 53.8% and 66.7%, respectively, with statistical difference. Positive expression of P53 was related to Ki-67 expression, but not to patients’ age, preoperative PSA level, postoperative Gleason score and nerve and invasion of neurovascular cancer embolus. 【Conclusion】 P53 expression is related to tumor stage and Ki-67, while Ki-67 expression is associated with tumor stage ang grade.

16.
Chinese Journal of Biologicals ; (12): 163-165+171, 2023.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-965862

ABSTRACT

@#Objective To investigate the effect of silencing E6-associated protein(E6AP)on the level of p53 protein in human papilloma virus(HPV)negative cervical cancer cells(C33A cells).Methods The siRNA sequence silencing E6AP(siE6AP)and silencing control disordered siRNA sequence(siControl)were transfected into C33A cells with the mediation of LipofectamineTM2000 transfection reagent respectively.The silencing effect of siRNA on E6AP and the expression of p53and cleaved-caspase-3 proteins were detected by Western blot.Results The levels of E6AP protein in C33A cells of siE6AP group were significantly lower(t =-4.597,P<0.05),while the levels of p53 and cleaved-caspase-3 proteins were significantly higher than those of siControl group(t = 4.533 and 7.099 respectively,each P<0.05).Conclusion Silencing of E6AP significantly increased the expression of p53 protein in C33A cells,indicating that silencing of E6AP may restore the activity and function of p53 protein in C33A cells.

17.
Diagn Pathol ; 17(1): 92, 2022 Dec 05.
Article in English | MEDLINE | ID: mdl-36471402

ABSTRACT

BACKGROUND: TP53 is the most frequently mutated gene in the human cancer, and the awareness of its mutational status is useful in the diagnosis and treatment of cancer patients. In the present study, we investigated the association between TP53 gene mutations and p53 immunohistochemical staining (IHC) patterns and non-genetic effect of MDM2 as a negative regulator of p53. METHODS: A total of 135 solid cancer cases with next generation sequencing data were subjected to p53 IHC and classified as overexpression, null type or usual pattern. RESULTS: TP53 mutation was observed in 104 out of 135 cases (77.0%). When the TP53 mutations were annotated into DISRUPTED (truncations, frameshifts, splice site mutations, and deep deletions) and IF-DBD (in-frame mutations in the DNA binding domain), the null type p53 IHC pattern was associated with DISRUPTED mutations (sensitivity 86.2%, specificity 97.2%) while the overexpression pattern was associated with IF-DBD mutations (sensitivity 100%, specificity 81.7%). The specificity of p53 IHC usual pattern predicting wild type TP53 was also as high as 100%. Regardless of MDM2 amplification, p53 IHC pattern showed a perfect association with TP53 mutation pattern. CONCLUSIONS: p53 IHC pattern (overexpression, null type, usual) reasonably predicted TP53 mutational status (DISRUPTED, IF-DBD), and MDM2 amplification status did not have any impact on the p53 IHC pattern.


Subject(s)
Neoplasms , Tumor Suppressor Protein p53 , Humans , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , Genes, p53 , Immunohistochemistry , Mutation , Neoplasms/diagnosis , Neoplasms/genetics , Biomarkers
18.
Afr Health Sci ; 22(2): 343-347, 2022 Jun.
Article in English | MEDLINE | ID: mdl-36407406

ABSTRACT

Background: The expression of p53 has been associated with the severity of other types of cancer. There is scanty information when it comes to oesophageal cancer. Objective: This study aimed to explore the use of p53 protein expression as an indicator of oesophageal cancer severity from a high-risk incidence in the African rural population. Methods: Fifty-one patients newly diagnosed with oesophageal cancer were recruited from the endoscopic unit at Nelson Mandela Academic Hospital in Mthatha, South Africa. The serological expression of p53 was measured using the ELISA method and the severity of oesophageal cancer expressed in grade was obtained from the histopathology report from patient's oesophageal biopsies. Results: We found that the expression of p53 was equally distributed among the histological grades of cancer with the value of 2495 pg/mL ± 1736 pg/ mL for lower grades and 2520 ± 1539 pg/mL for higher grades. Furthermore, we found that the level of p53 expression was equally distributed in patients from grade 1, 2, 3, and 4. Conclusion: The expression of p53 protein does not vary according to the histological grade of oesophageal cancer in the given population, therefore may not be helpful as a prognostic factor.


Subject(s)
Carcinoma, Squamous Cell , Esophageal Neoplasms , Humans , Tumor Suppressor Protein p53/metabolism , Incidence , Esophageal Neoplasms/diagnosis , Esophageal Neoplasms/epidemiology , Esophageal Neoplasms/genetics , Carcinoma, Squamous Cell/epidemiology , South Africa
19.
Cells ; 11(21)2022 11 02.
Article in English | MEDLINE | ID: mdl-36359870

ABSTRACT

BACKGROUND: Mutation of the TP53 gene is one of the major drivers of myelodysplastic neoplasias (MDS) and acute myeloid leukemia with myelodysplasia-related changes (AML-MR). TP53 mutations present in these hematopoietic malignancies form a distinct molecular genetic cluster with a worse prognosis than without the alteration. However, besides well-characterized hot-spot variants, a significant proportion of TP53 alterations are of uncertain clinical significance. METHODS: To enlighten so far unknown aspects, bone-marrow samples from altogether 77 patients are analyzed retrospectively with the diagnosis of AML-MR (26 cases), MDS-IB (12 cases), and MDS-LB (39 cases) according to WHO 2022 guidelines. Next-generation sequencing results are correlated with histological, cytogenetic, and survival data. RESULTS: Twenty out of the 30 TP53 mutation types detected by NGS are not categorized in current public databases; thus, their clinical significance remained mysterious. Because of the interpretation difficulties and the absence of clinical correlations, pathogenicity is established based on in silico approaches. The 12 pathogenicity classification systems, as well as protein stability, protein-DNA, protein-protein interaction, and post-translational modification analyses are applied. We found statistically significant differences between AML/MDS groups considering p53 pathogenicity, protein structural changes, and overall survival. The largest number of abnormalities with the most severe consequences are found in AML-MR cases. CONCLUSIONS: These molecular and in silico protein data further support that MDS with increased-blast (MDS-IB) is an intermediate group between AML-MR and MDS with low-blast (MDS-LB) patients, which frequently progresses to AML and is therefore considered a pre-leukemic condition.


Subject(s)
Leukemia, Myeloid, Acute , Myelodysplastic Syndromes , Humans , Genes, p53 , Leukemia, Myeloid, Acute/genetics , Leukemia, Myeloid, Acute/pathology , Myelodysplastic Syndromes/genetics , Myelodysplastic Syndromes/pathology , Retrospective Studies , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism
20.
J Cell Biochem ; 123(12): 1891-1937, 2022 12.
Article in English | MEDLINE | ID: mdl-36183376

ABSTRACT

The protein p53 has been extensively investigated since it was found 43 years ago and has become a "guardian of the genome" that regulates the division of cells by preventing the growth of cells and dividing them, that is, inhibits the development of tumors. Initial proof of protein existence by researchers in the mid-1970s was found by altering and regulating the SV40 big T antigen termed the A protein. Researchers demonstrated how viruses play a role in cancer by employing viruses' ability to create T-antigens complex with viral tumors, which was discovered in 1979 following a viral analysis and cancer analog research. Researchers later in the year 1989 explained that in Murine Friend, a virus-caused erythroleukemia, commonly found that p53 was inactivated to suggest that p53 could be a "tumor suppressor gene." The TP53 gene, encoding p53, is one of human cancer's most frequently altered genes. The protein-regulated biological functions of all p53s include cell cycles, apoptosis, senescence, metabolism of the DNA, angiogenesis, cell differentiation, and immunological response. We tried to unfold the history of the p53 protein, which was discovered long back in 1979, that is, 43 years of research on p53, and how p53's function has been developed through time in this article.


Subject(s)
Neoplasms , Tumor Suppressor Protein p53 , Humans , Animals , Mice , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , DNA
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