ARTICLE | doi:10.20944/preprints202105.0267.v1
Subject: Medicine & Pharmacology, Clinical Neurology Keywords: Alzheimer’s disease; AD; blood-based biomarker; p53; unfolded p53; U-p53
Online: 12 May 2021 (11:21:18 CEST)
Background: Research continues to search for blood-based biomarkers sensitive to Alzheimer’s disease (AD) pathology during the initial stages when symptoms of cognitive decline are not yet apparent. A blood-based biomarker candidate is metalloprotein p53, the conformation of which was previously found to be altered in peripheral cells from individuals with mild cognitive impairment (MCI) and AD, presenting as an unfolded p53 (U-p53) conformational variant. Methods: Plasma samples from the well-characterized Australian Imaging, Biomarkers, and Lifestyle (AIBL) cohort were used to identify the clinically relevant AZ 284® peptide, specifically present in samples from individuals with symptomatic AD. The AZ 284® peptide, which is a marker of the U-p53 conformational variant (U-p53AZ), was identified by immunoprecipitation (IP) with a novel U-p53 conformational variant-specific antibody followed by liquid chromatography (LC) tandem mass spectrometry (MS/MS) and protein sequencing. Using IP-LC surface-activated chemical ionization (SACI) MS/MS analysis, the prognostic and diagnostic performance of U-p53AZ were examined in the longitudinal AIBL cohort, including 252 plasma samples derived from 214 elderly individuals. For the prognostic analyses, U-p53AZ levels were assessed at 36, 72, and 90 months after baseline assessment. Results: The prognostic performance of U-p53AZ to predict the progression to AD from preclinical or prodromal AD was high, with area under the receiver operating characteristic curve (AUC) values close to or above 0.90. Furthermore, U-p53AZ predicted the progression to AD more than 6 years prior to symptom onset with positive and negative predictive values of about 90%. Additionally, the estimated prognostic performance of U-p53AZ was superior to other main risk factors (i.e., age, sex, and either alone or in combination with amyloid status. Furthermore, U-p53AZ had high diagnostic performance to differentiate cognitively normal individuals from those with AD (AUC values >0.88). Conclusion: These findings support the use of U-p53AZ as a prognostic blood-based biomarker accurately predicting the progression to AD dementia during the preclinical and prodromal stages at least 6 years before receiving the clinical diagnosis of AD dementia.
REVIEW | doi:10.20944/preprints202201.0020.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: P53; mutant p53; targeting therapy; immunotherapy; cancer
Online: 4 January 2022 (20:34:14 CET)
TP53 is a tumor suppressor gene that encodes a sequence-specific DNA-binding transcription factor activated by stressful stimuli and upregulates target genes involved in growth suppression, cell death, DNA repair, metabolism, among others. P53 is the most frequently mutated gene in tumors with mutations not only leading to loss-of-function (LOF), but also gain-of-function (GOF) which promotes tumor progression, and metastasis. The tumor-specific status of mutant p53 protein has suggested it is a promising target for cancer therapy. We summarize the current progress of targeting wild-type and mutant p53 for cancer therapy through biotherapeutic and biopharmaceutical methods for 1) boosting p53 activity in cancer, 2) p53-dependent and p53-independent strategies for targeting p53 pathway functional restoration in p53-mutated cancer, 3) targeting p53 in immunotherapy, and 4) combination therapies targeting p53, p53 checkpoints, or mutant p53 for cancer therapy.
ARTICLE | doi:10.20944/preprints202005.0063.v1
Subject: Life Sciences, Molecular Biology Keywords: p53-Mdm2; mutant p53; oncogene; stress; regulatory network; cancer dynamics
Online: 5 May 2020 (05:55:27 CEST)
We study a minimal model of the stress-driven p53 regulatory network that includes competition between active and mutant forms of the tumor-suppressor gene p53. Depending on the nature of the external stress signal, four distinct dynamical states are observed. These states can be distinguished by dierent dynamical properties and correspond to active, apoptotic, pre-malignant and cancer states. Transitions between any two of these states are found to be unidirectional and irreversible if the stress signal is either oscillatory or constant. When the signal decays exponentially, the apoptotic state vanishes, and for low stress the pre-malignant state is bounded by two critical points, allowing the system to transition reversibly from the active to the pre-malignant state. For signicantly large stress, the range of the pre-malignant state expands and the system moves to the cancerous state which is a stable attractor. This suggests that identification of the pre-malignant state may be important both for therapeutic intervention as well as for drug discovery.
REVIEW | doi:10.20944/preprints202106.0158.v1
Online: 7 June 2021 (09:29:06 CEST)
p53 is among the most frequently mutated tumor suppressor genes given its prevalence in >50% of all human cancers, including high grade serous endometrial cancers and ovarian cancers. In addition to loss of tumor suppression function, many mutated p53 (Mutp53) proteins acquire gain-of-function (GOF) activities as oncogenes to promote cancer progression, which manifest through aberrant expression of p53. As we have come to see, statins induce CHIP-mediated degradation of mutp53 by blocking the interaction between mutp53 and DNAJA1. Therefore, targeting critical downstream pathways of mutp53 provides an alternative strategy for treating cancers expressing mutp53. In this review, we summarize recent advances with Wee1 inhibitors and mevalonate pathway inhibitors, particularly statins, regarding their use in gynecological cancers with p53 mutations.
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: Meta-analysis; p53 wild type antibodies; p53 mutant antibodies; cancer survival prognostic factor.
Online: 24 September 2021 (12:46:26 CEST)
Importance: p53 is an unequivocal tumor suppressor altered in half cancers. The immune system produces systemic p53 autoantibodies (p53 Abs) in many cancer patients. Objective: The focus of this systemic review and meta-analysis is on the prognostic value of p53 Abs expressed in the serum of patients with solid tumors. Data Sources: All the clinical investigations were searched on PubMed, MBase and Cochrane from 1993 reporting the first study until May 2021. Study Selection: Studies were included that met the following criteria: 1) participants with cancer; 2) outcome results expressed in relation to the presence of a p53 antibody; 3) a primary outcome (disease free survival, overall survival or progression free survival) expressed as hazard ratio (HR). The following exclusion criteria were used: 1) insufficient data available to evaluate outcomes; 2) animal studies; 3) studies with less than 10 participants. 1333 potentially relevant articles; studies as duplicates, non-patients studies or reviews were excluded. After viewing the titles and abstracts of the 52 remaining studies, the full texts of 34 studies were retrieved and 12 studies were included in the analysis. Data Extraction and Synthesis: PRISMA guidelines were used for abstracting and assessing data quality and validity by three independent observers. The summary estimates were generated using a fixed-effect model (Mantel–Haenszel method) or a random-effect model (DerSimonian–Laird-method) depending on the absence or presence of heterogeneity (I2). Main Outcome(s) and Measure(s): The primary study outcome was to determine the prognostic value of p53 Abs from a large population size of patients with solid tumors, as determined before data collection. Results: In total 12 clinical studies and of which 2094 patients were included and it was determined that p53-wt Abs expression in the serum significantly correlated with a worse survival of cancer patients (95% CI 1.48 [1.24, 1.77]; p<0.00001). On the contrary, data from literature indicated that there was a potential association between p53-mut Abs antibodies with better survival. Conclusions and Relevance: This is the first meta-analysis proving the diagnostic utility of p53-Abs for cancer patients, predicting a worse outcome. The serum-p53 value (s-p53-value) could be useful for future theranostics.
REVIEW | doi:10.20944/preprints202109.0063.v1
Online: 3 September 2021 (13:13:48 CEST)
P53 is known as the most critical tumor suppressor and is often referred to as the guardian of our genome. More than 40 years after its discovery, we are still struggling to understand all molecular details on how this transcription factor prevents oncogenesis or how to leverage current knowledge about its function to improve cancer treatment. Multiple cues, including DNA-damage or mitotic errors, can lead to the stabilization and nuclear translocation of p53, initiating the expression of multiple target genes. These transcriptional programs may well be cell type and stimulus-specific, as is their outcome that ultimately imposes a barrier to cellular transformation. Cell cycle arrest and cell death are two well-studied consequences of p53 activation, but, while being considered as critical, they do not fully explain the consequences of p53 loss-of-function phenotypes in cancer. Here, we discuss how mitotic errors alert the p53 network and give an overview on multiple ways how p53 can trigger cell death. We argue that a comparative analysis of different types of p53 responses, elicited by different triggers in a time-resolved manner in well-defined model systems is critical to understand cell type specific cell fate induced by p53 upon its activation, in order to resolve the remaining mystery of its tumor suppressive function.
REVIEW | doi:10.20944/preprints201804.0181.v2
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: p53, JMY, regulation, apoptosis, motility
Online: 18 April 2018 (13:46:19 CEST)
Following an event damaging the DNA, p53 levels increases inducing cell cycle arrest or apoptosis. JMY protein is a transcription co-factor involved in p53 regulation. After a DNA damage, also JMY levels increase and, as this protein accumulates in the nucleus, it forms a complex with P300 and Strap1 which increases the ability of p53 to induce transcription of proteins triggering apoptosis but not cell cycle. Therefore, Increase levels of JMY “direct” p53 activity toward triggering apoptosis. JMY expression is also linked to increased motility as it downregulates the expression of adhesion molecules of the Cadherin family and induces actin nucleation, making the cell less adhesive and more mobile. According to the scenario this gene can therefore have both a suppressive or a tumour promoting activity.
REVIEW | doi:10.20944/preprints202109.0359.v1
Online: 21 September 2021 (12:01:29 CEST)
Our understanding of Alzheimer’s disease (AD) pathogenesis has developed with several hypotheses over the last 40 years, including the Amyloid and Tau hypotheses, respectively. More recently, the p53 protein, well-known as ‘the guardian of the genome,’ has gained attention for its role in the early evolution of AD. This is due to p53’s central role in the control of oxidative stress and potential involvement in both Amyloid and Tau pathways. p53 is commonly regulated by post-translational modifications (PTMs), which affect its conformation, increasing its capacity to adopt multiple structural and functional states, including those that can influence several processes in AD. The following review will explore the impact of p53 post-translational modifications (PTMs) on its function and consequential involvement in AD pathogenesis.
ARTICLE | doi:10.20944/preprints201901.0315.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: glioblastoma; p53; apoptosis; doxorubicin; bortezomib; vorinostat.
Online: 30 January 2019 (13:03:22 CET)
In prostate cancer, p53 maximizes apoptosis in response to severe DNA damage, not DNA replication stress. Here, we examined the apoptotic response of two glioblastoma cells, p53-wild type U87 and a p53-mutated T98G cell, for the same stresses. We ascertained that p53 intensified apoptosis in response to severe DNA damage, not DNA replication stress in glioblastoma. We further asked if p53-mediated apoptosis can be induced by cellular stress other than severe DNA damage. We analyzed two compounds, bortezomib and vorinostat, respective inhibitors of 26S proteasome and histone deacetylase, to evaluate their capacity to activate p53-mediated apoptosis. The cellular stress incited by bortezomib, not vorinostat, activated p53-mediated apoptosis. Next, we asked if the cellular stress generated by combining the two compounds had a synergistic effect on apoptosis. Our results demonstrated that doxorubicin with bortezomib or CFS-1686, or bortezomib with vorinostat have a significant synergistic effect on apoptosis only in p53-wild type cell. Under high stress, p53 translocates from cytosol into the nucleus to cause apoptosis possibly. Together, p53 maximizes apoptosis for cellular stress caused by severe DNA damage, disruption of protein turnover, and for the stress induced by drug combination including doxorubicin with bortezomib or CFS-1686, and bortezomib with vorinostat.
ARTICLE | doi:10.20944/preprints202103.0104.v1
Online: 2 March 2021 (16:02:07 CET)
Hepato-renal dysfunctions associated with hyperlipidemia necessitates continuous search for natural remedies. This study thus, evaluated the effect of dietary chitosan on diet-induced hyperlipidemic rats. Thirty male Wistar rats (90 ± 5.2) g were randomly allotted into six (6) groups (n=5): Normal diet, High-fat diet (HFD), Normal diet + 5% chitosan. The three other groups received HFD, supplemented with 1%-, 3%-, and 5% of chitosan. The feeding lasted for 8 weeks, after which the rats were sacrificed. The liver and kidneys were harvested for Analyses. Hepatic alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) activity, and renal biomarkers (ALT, AST, urea, and creatinine) were assayed spectrophotometrically. Additionally, expression of hepatic and renal CD43 and p53 was estimated immunohistochemically. Hyperlipidemia caused a significant (p<0.05) decrease in the hepatic (AST, ALT, and ALP) and renal (AST and ALT) activities, while renal urea and creatinine increased. Furthermore, the HFD group showed an elevated level of hepatic and renal CD43 while p53 expression decreased. However, groups supplemented with chitosan showed improved hepatic and renal biomarkers, as well as corrected the aberrations in the expressions of p53 and CD43. Conclusively, dietary chitosan could effectively improve kidney and liver functionality via abatement of inflammatory responses.
ARTICLE | doi:10.20944/preprints202101.0530.v1
Subject: Medicine & Pharmacology, Clinical Neurology Keywords: Alzheimer’s disease; biomarker; prognosis; P53; mass spectrometry
Online: 26 January 2021 (10:01:35 CET)
Despite the increasing number of individuals affected by Alzheimer’s disease (AD) every year, no effective therapy has been developed to treat this neurodegenerative disease yet. The current methods for AD diagnosis are effective for clinical confirmation of the disease only when symptoms become apparent, years after molecular damage started within the patients’ brains. As higher expression of a conformationally altered p53 has been correlated with AD, we developed a mass spectrometry-based method for highly sensitive, specific, and reproducible quantification of a p53 conformational variant in plasma samples of patients with known clinical outcome. In particular, we tested the prognostic performance of an AD-specific 2D3A8-immunoselected p53 peptide (AZ 284™) in different sets of individuals progressing from both cognitively unimpaired (CU) and mild cognitive impairment (MCI) patients progressing to AD dementia. Our data showed that quantitative analysis of AZ 284™ is a reliable tool for predicting AD progression up to 6 years prior to dementia onset with AUC >90%. Taken together, these results support the implementation of p53 conformational variant quantification as an affordable and powerful diagnostic tool for early, non-invasive AD diagnosis.
ARTICLE | doi:10.20944/preprints202008.0562.v1
Online: 26 August 2020 (09:10:14 CEST)
Introduction: The tumour suppressor protein p53 commonly referred to as guardian of the genome plays important role in preserving the genome through the regulation of programmed cell death, DNA repair, energy metabolism, cell cycle entry or exit and senescence. Mutations in p53 can either result to a loss of tumour suppressor function or gain of oncogenic properties. Hence, mutations in p53 are the most frequent genetic mutational alteration in human cancers, associated with worse prognosis and more aggressive disease outcome. Methods: To assess the mutational hotspots and conserved regions of p53, I analyzed 76 complete p53 protein sequences covering whole exons from the NCBI GenBank database. Multiple sequence alignment (MSA) was done using ClustalX version 2.1. Results: Thirty-five (19) mutations were identified with more frequent mutations in amino acid (aa) position 72 and 79 (Exon 4), amino acid deletion in codon 112-122 (Exon 4), codon 213 (Exon 6), codon 248 (Exon 7), codon 273 (Exon 8) and codon 278 (Exon 8). Mutations at amino acid position 79, 248, 278 located in the DNA-binding domain exhibited more than one alteration in same position. Conclusions: Findings from this study revealed the prevalence of mutations in the DNA binding domain of p53 and the structure-function effect of the mutations. Assessing the pattern and frequency of p53 alterations, and analyzing it thoroughly for each carrier, could help in identifying correlations between p53 status and outcome and possible candidate for gene therapy.
ARTICLE | doi:10.20944/preprints201910.0180.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: long term survival; Glioblastoma; IDH; EGFR; Ki67; p53
Online: 16 October 2019 (08:30:25 CEST)
Background: Glioblastomas (GBM) is generally burdened, to date, by a dismal prognosis, although Long Term Survivors have a relatively significant incidence. Our specific aim was to determine the exact impact of many surgery-, patient- and tumor-related variable on Survival parameters. Methods: The surgical, radiological and clinical outcomes of patients have been retrospectively reviewed for the present study. All the patients have been operated on in our Institution and classified according their Overall Survival in LTS (Long Term Survivors) and STS (Short Term Survivors). A thorough Review of our surgical series was conducted to compare the oncologic results of the patients in regards to 1. Surgical , 2. Molecular, and 3.Treatment related features. Results: A total of 177 patients were included in the final cohort. Extensive statistical analysis by means of univariate, multivariate and survival analyses disclosed a survival advantage for patients presenting a younger age, a smaller lesion and a better functional status at presentation. From the Histochemical point of view, Ki67(%) was the strongest predictor of better oncologic outcomes. A stepwise analysis of variance outlines the existence of 8 prognostic subgroups according to the molecular patterns of Ki67 overexpression and EGFR, p53 and IDH mutations. Conclusions: On the ground of our statistical analyses we can affirm that the following factors were significant predictors of survival advantage: KPS, Age, Volume of the lesion, Motor disorder at presentation, a Ki67 overexpression. A fine molecular profiling is feasible to precisely stratify the prognosis of GBM patients.
ARTICLE | doi:10.20944/preprints202004.0312.v1
Subject: Life Sciences, Biochemistry Keywords: chalocomoracin; proliferative vitreoretinopathy; vitreous; Akt; p53; migration; proliferation; contraction
Online: 19 April 2020 (02:18:01 CEST)
Retinal pigment epithelial (RPE) cells are the major cell type in the epi- or sub-retinal membranes in the pathogenesis of proliferative vitreoretinopathy (PVR), which is a blinding fibrotic eye disease and still short of effective medicine. The purpose of this study is to demonstrate if Chalocomoracin (CMR), a novel purified compound from fungus-infected mulberry leaves, is able to inhibit vitreous-induced signaling events and cellular responses intrinsic to PVR. Our studies have revealed that the CMR IC50 for ARPE-19 cells is 35.5 μM at 72 hours, and that 5 μM CMR inhibits vitreous-induced Akt activation and p53 suppression; in addition we have discovered that this chemical effectively blocks vitreous-stimulated proliferation, migration and contraction of ARPE-19 cells, suggesting that CMR is a promising PVR prophylactic.
ARTICLE | doi:10.20944/preprints201902.0177.v1
Subject: Life Sciences, Virology Keywords: Bovine cutaneous papilloma, Iraq, Immunohistochemical (IHC), hyperkeratosis, p53 marker.
Online: 19 February 2019 (11:04:23 CET)
Background: Papillomaviruses (PVs) are double-stranded DNA viruses and are more common in skin of ruminants in Iraq. A P53 (tumor suppressor protein) reveals an essential role in cell cycle control. This study aimed to describe the clinical, histopathological and immunohistochemical aspects of naturally occurring cutaneous ruminant’s papillomatosis. Methods: Samples were collected from totally, 10 animals (3 cattle, 3 goats and 4 sheep) with multiple papillomatosis lesions. Results: Clinically, exophytic multiple, cauliflower-like growths (warts) of varying sizes (0.5-11 cm) were found in different areas of the animal’s bodies. Histopathological features were various degrees of koilocytosis, ortho and parakeratotic, hyperkeratosis, hypergranulosis in granular layer and acanthosis. Immunohistochemical (IHC) investigations revealed some nuclei in the granular and basal layers of the epidermis with intense positivity for papillomavirus antigen. All tumor samples were positive for p53 expression that appeared as a strong cytoplasmic and perinuclear staining mainly in the basal and parabasal layers. Conclusion: this study described the papillomavirus lesions in bovine, ovine and caprine, that located in different anatomical areas with minor variations in histopathological features. The tumor samples showed positive results for PV antigen and P53 expression that considered as the useful markers in the diagnosis of cutaneous papilloma.
Subject: Life Sciences, Biochemistry Keywords: p53; nucleophosmin; mutation; acute myeloid leukemia; FLIM-FRET; Selinexor; photoconversion
Online: 28 May 2021 (13:35:48 CEST)
NPM interaction with tumor suppressor p53 is a part of a complex interaction network and considerably affects cellular stress response. An impact of characteristic AML-associated NPM mutations on interaction with p53 has not been investigated yet, although consequences of NPMmut-induced p53 export to the cytoplasm are important for understanding of leukemogenic potential of these mutations. We investigated p53-NPM interaction in live HEK-293T cells by FLIM-FRET and in cell lysates by immunoprecipitation. Results were confirmed in leukemia cell lines. eGFP lifetime-photoconversion was used to follow redistribution dynamics of NPMmut and p53 in Selinexor-treated cells. We confirmed the p53-NPMwt interaction in intact cells and newly documented that this interaction is not compromised by the NPM mutation causing displacement of p53 to the cytoplasm. Importantly, the interaction was not abolished for non-oligomerizing NPM variants with truncated oligomerization domain, suggesting that oligomerization is not essential for interaction of NPM forms with p53. Inhibition of the nuclear exporter XPO1 by Selinexor caused expected nuclear relocalization of both NPMmut and p53. However, significantly different return rates of these proteins indicate nontrivial mechanism of p53 and NPMmut cellular trafficking. We suggest that the altered p53 regulation in cells expressing NPMmut offers a new target for AML therapy.
ARTICLE | doi:10.20944/preprints201810.0121.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: SAHA; RG7388; MDM2; p53; p21; cell cycle arrest; cell death
Online: 7 October 2018 (11:33:18 CEST)
Alterations in gene expressions are often due to epigenetic modifications that can lead to significant influence on cancer development, growth, and progression. The main epigenetic modifications observed in human are methylation and acetylation. In this regard, the HDAC inhibitors (HDACi) such as SAHA (Vorinostat), which can exert epigenetic alterations through impacting the acetylation status of histones, are in clinical trials as a new class of drugs with promising effects on the cancer growth and metastatic process. The small molecule RG7388 is a newly developed inhibitor that is specific for an oncogene-derived protein called MDM2, which is in clinical trials for the treatment of various types of cancers. One of the common characteristics for these two drugs is their ability to induce p21 expression through distinct mechanisms in MCF-7 and LNCaP cells. This difference was expected trigger cell cycle arrest and cell death through intra-cellular mechanisms that are not identical. Hence, the molecular mechanism whereby SAHA can induce cell cycle arrest and trigger necrosis, apoptosis or necroptosis is still evolving. Similarly, the ability of RG7388 for producing anticancer effect is undergoing thorough investigation, since it can produce p53 dependent and p53 independent effects. In this study we performed experiments to measure the cell cycle arrest effects of SAHA and RG7388 on using MCF-7 and LNCaP cells. The cytotoxicity, cell cycle arrest and apoptosis/necroptosis effects of the treatments were assessed by using Trypan Blue Dye Exclusion (TBDE) method, MTT assay, Fluorescence assay with DEVD-amc fluorogenic substrate and Immunoblotting methods. Our results from MCF-7 and LNCaP cells confirmed that SAHA and RG7388 treatments were able to induce cell death via combination of cell cycle arrest and cytotoxic mechanisms. We are speculating that our findings could lead to the development of newer treatments for breast and prostate cancers using this type of combinations.
ARTICLE | doi:10.20944/preprints201808.0146.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: histone deacetylase inhibitor, MHY2256, p53, apoptosis, autophagy, Ishikawa, endometrial cancer
Online: 7 August 2018 (14:37:46 CEST)
We previously found a novel a new sirtuin (SIRT) inhibitor MHY2256 that exerts anticancer activity through p53 acetylation in MCF-7 human breast cancer cells. Here, we investigated the anticancer activity of MHY2256 against hormone-related cancer, which is an endometrial cancer with poor prognosis. We found that MHY2256 markedly reduced cellular proliferation at low concentrations against Ishikawa endometrial cancer cells. The IC50 values of MHY2256 were much lower than that of salermide. Furthermore, MHY2256 significantly reduced the protein expression and activities of SIRT1, 2, and 3 with similar effects as salermide, a well-known SIRT inhibitor. Particularly, MHY2256 markedly inhibited tumor growth in a tumor xenograft mouse model of Ishikawa cancer cells. During the experimental period, there was no significant change in the body weight of mice treated with MHY2256. Detailed analysis of the sensitization mechanisms of Ishikawa cells revealed that late apoptosis was largely increased by MHY2256. Additionally, MHY2256 increased G1 arrest and reduced cell cyclic-related proteins, suggesting that apoptosis by MHY2256 was achieved by cellular arrest. Particularly, p21 was greatly increased by MHY225656, suggesting that cell cycle arrest by p21 is a major factor in MHY2256 sensitization in Ishikawa cells. We also detected a significant increase in acetylated p53, a target protein of SIRT1, in Ishikawa cells after MHY2256 treatment. In a mouse xenograft model, MHY2256 significantly reduced tumor growth and weight without apparent side effects. These results suggest that MHY2256 exerts its anticancer activity through p53 acetylation in endometrial cancer and can be used for targeting hormone-related cancers.
REVIEW | doi:10.20944/preprints202210.0341.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: Chromosomal instability; aneuploidy; p53; BCL2 family; apoptosis; spindle assembly checkpoint; cancer
Online: 21 October 2022 (14:24:51 CEST)
Aneuploidy describes the gain or loss of entire chromosomes or chromosome arms. Already more than 100 years ago, aneuploidy was described to be featured in cancer and it is known today to be present in 68-90 % of cancers, depending on tumour entity. Aneuploidy is implicated to affect cancer growth, therapy response and frequently affects prognosis. Chromosomal instability (CIN) is recognized as the main cause of aneuploidy and is characterised as the fluent process of gaining or losing chromosomes. Chromosomally instable cells need to be kept in check, or cleared, to prohibit the sampling of aneuploid karyotypes able to drive tumorigenesis. Of note, even aneuploid cancer cells often show CIN, a feature that promotes therapy related drug-resistance. Here, we review how CIN can be prevented or limited to spread by the induction of cell death and the relevance of different p53 responses triggered in response to mitotic perturbations to prohibit the formation of cancer driving aneuploidies.
REVIEW | doi:10.20944/preprints202008.0729.v2
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: p53; p73; MDM2; MDMX; tumor suppressor; drug repurposing; aspirin; protoporphyrin IX; verteporfin
Online: 17 September 2020 (07:23:37 CEST)
p53 and p73 are critical tumor suppressors often inactivated in human cancers through various mechanisms. Owing to high structural homology, the proteins have many common functions and recognize the same set of genes involved in apoptosis and cell cycle regulation. p53 is known as the ‘guardian of the genome’ and together with p73 form a barrier against cancer development and progression. The TP53 is mutated in more than 50% of all human cancers and the germline mutations in TP53 predispose to the early onset of multiple tumors in Li-Fraumeni Syndrome (LFS), the inherited cancer predisposition. In cancers where TP53 gene is intact, p53 is degraded. Despite the ongoing efforts, the treatment of cancers remains challenging. This is due to late diagnoses, the toxicity of current standard of care and marginal benefit of newly approved therapies. Presently, the endeavours focus on reactivating p53 exclusively, neglecting the potential of the restoration of p73 protein for cancer eradication. Taken that several small molecules reactivating p53 failed in clinical trials, there is a need to develop new treatments targeting p53 proteins in cancer. This review outlines the most advanced strategies to reactivate p53 and p73 and describes drug repurposing approaches for the efficient reinstatement of the p53 proteins for cancer therapy.
ARTICLE | doi:10.20944/preprints201912.0382.v1
Subject: Medicine & Pharmacology, Clinical Neurology Keywords: glioblastoma multiforme; MGMT; IDH1; EGFR; P53; ATRX; Ki67; neurosurgery; oncology; epilepsy
Online: 29 December 2019 (13:04:12 CET)
Glioblastoma is a solid, infiltrating and the most frequent highly malignant primary brain tumor. Our aim was to find the prognostic value of mutations of IDH1, MGMT, EGFR, p53, ATRX, Ki67 genes and the correlation between sex, age, presenting with seizures, number of interventions, extent of resection with Overall Survival (OS), Progression Free Survival (PFS) and Karnofsky performance status (KPS) score. A randomized retrospective analysis of 122 patients treated by a single operator at Sapienza University of Rome, was carried out. After surgery patients followed standard treatment Stupp protocol . Exclusion criteria were: patients with primitive brainstem and spinal cord gliomas and patients who underwent partial resections (resection < 90%) and cases of brain biopsy exclusively for diagnostic purposes. Statistical analysis with a simultaneous regression model was carried on by SPSS 25 ® (IBM) program. Results showed statistically significant survival increase in four groups: 1) patients treated with gross total resection (p< 0.03); 2) patients with methylated MGMT promoter (p<0.005); 3) patients with non EGFR amplification or EGFRvIII mutation (p<0.035); 4) mutated IDH1/IDH2 (p<0.0161). Higher survival rates (but not statistically significant) were observed also in patients with: age < 75 years, Ki 67 <10%, lesions in non eloquent areas, ATRX gene mutation and presentation with seizures.
REVIEW | doi:10.20944/preprints201908.0002.v1
Subject: Biology, Physiology Keywords: p53; irradiation; medaka; developing brain; testis; apoptosis; embyogenesis; regeneration, mis-differentiation
Online: 1 August 2019 (03:46:42 CEST)
The tumor suppressor protein p53 is considered a guardian of genome integrity, regulating the induction of apoptosis and cell cycle arrest in response to irradiation to block the transmission of teratogenic mutations to progeny cells. We examined the function of p53 in highly radiosensitive tissues, the developing brain and mature testis, using a small fish model, medaka (Oryzias latipes). Medaka offer advantages as a vertebrate model system, as the transparency and small size of the embryos enables clear detection of apoptotic cells in the developing brain. In addition, the simple architecture of medaka testes enables more precise identification of the differentiating spermatogenic stages compared with mammals. We found that in irradiated p53-deficient embryonic brain, diminished induction of apoptosis facilitated tissue regeneration earlier compared to irradiated wild-type embryos, which remained structural abnormalities in the retina at hatching. Moreover, the prominent delay in apoptotic induction in irradiated p53-deficient testes could induce transient mis-differentiation during spermatogenesis, such as the formation of ovum-like cells (testis-ova). However, all testis-ova cells were eliminated via p53-independent apoptosis, and spermatogenesis was completely restored within 1 month after irradiation. Collectively, these data indicate that p53 is not indispensable for the restoration of irradiation-induced damaged tissues.
ARTICLE | doi:10.20944/preprints201805.0088.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: p53; proteasome inhibitor; endometrial cancer; ovarian cancer; gain-of-function mutation
Online: 4 May 2018 (09:03:27 CEST)
Mutations in the “guardian of the genome” TP53 predominate in solid tumors. In addition to loss of tumor suppressor activity, a specific subset of missense mutations confers additional oncogenic properties. These “gain-of-function” (GOF) mutations portend poor prognosis across cancer types regardless of treatment. Our objective in this study was to identify novel therapeutic opportunities to overcome the deleterious effects of GOF TP53 mutants. Using gynecologic cancer cell lines with known TP53 mutational status, we established that treatment with a proteasome inhibitor induced cell death in cells with two recurrent GOF TP53 mutations (R175H and R248Q), and addition of a histone deacetylase inhibitor (HDACi) enhanced this effect. By contrast, p53-null cancer cells were relatively resistant to the combination. Towards understanding the mechanism, we found that proteasome inhibition promotes apoptosis of cells with TP53 GOF mutations, potentially through induction of the unfolded protein response. In line with the reported hyperstabilization of GOF p53 protein, cells treated with HDACi exhibited reduced levels of p53 protein. Together, these data form the basis for future clinical studies examining therapeutic efficacy in a preselected patient population with GOF TP53 mutations.
ARTICLE | doi:10.20944/preprints202109.0265.v1
Subject: Life Sciences, Biophysics Keywords: poly-PR/GR; neurodegenerative disease; LLPS; p53; intrinsically disordered domains; membraneless organelles
Online: 15 September 2021 (14:43:48 CEST)
Abstract: The most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is the presence of poly-PR/GR dipeptide repeats which are encoded by the C9orf72 gene. Recently, it was shown that poly-PR/GR alters chromatin accessibility which results in stabilization and enhancement of transcriptional activity of the tumor suppressor p53 in several neurodegenerative disease models. Reduction of p53 protein levels in cell and model organisms protects against neurotoxicity of poly-PR, and partially protects against neurotoxicity of poly-GR. Here, we aimed to study the detailed molecular mechanisms how p53 contributes to poly-PR/GR mediated neurodegeneration. Using a combination of biophysical techniques such as nuclear magnetic resonance (NMR) spectroscopy, fluorescence polarization, turbidity assays and differential interference contrast (DIC) microscopy, we found that p53 physically interacts with poly-PR/GR and triggers liquid-liquid phase separation of p53. We identified p53 transactivation domain 2 (TAD2) as the main binding site for PR25/GR25 and show that binding of poly-PR/GR to p53 is mediated by a network of electrostatic and/or hydrophobic interactions. Our findings might help to understand the mechanistic role of p53 in poly-PR/GR - associated neurodegeneration.
ARTICLE | doi:10.20944/preprints202008.0028.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: Oncolytic virus; Mesenchymal stem cell; Prodrug activation; P53 mutant tumor; Colorectal cancer
Online: 2 August 2020 (12:31:32 CEST)
Although oncolytic viruses are currently being evaluated for cancer treatment in clinical trials, systemic administration is hindered by many factors that prevent them from reaching the tumor cells. When administered systemically, mesenchymal stem cells (MSCs) target tumors, and therefore constitute good cell carriers for oncolytic viruses. Methods: MSCs were primed with trichostatin A under hypoxia, which upregulated the expression of CXCR4, a chemokine receptor involved in tumor tropism, and coxsackievirus and adenovirus receptor that plays an important role in adenoviral infection. After priming, MSCs were loaded with conditionally replicative adenovirus that exhibits limited proliferation in cells with a functional p53 pathway and encodes Escherichia coli nitroreductase (NTR) enzymes (CRAdNTR) for targeting tumor cells. Results: Primed MSCs increased tumor tropism and susceptibility to adenoviral infection, and successfully protected CRAdNTR from neutralization by anti-Adenovirus antibodies both in vitro and in vivo, and specifically targeted p53-deficient colorectal tumors when infused intravenously. Analyses of deproteinized tissues by UPLC-MS/QTOF revealed that these MSCs converted the co-administered prodrug CB1954 into cytotoxic metabolites, such as 4-hydroxylamine and 2-amine, inducing oncolysis and tumor growth inhibition without being toxic for the host vital organs. Conclusion: This study shows that the combination of oncolytic viruses delivered by MSCs with the activation of prodrugs is a new cancer treatment strategy that provides a new approach for the development of oncolytic viral therapy for various cancers.
REVIEW | doi:10.20944/preprints202207.0432.v2
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: mutation; gastric cancer; p53; K-Ras; c-Myc; cancer genomics; targeted therapy; immunotherapy
Online: 16 August 2022 (10:35:16 CEST)
The genetic changes appearing in the information system of the cell that program its unregulated growth and proliferation gradually lead to cancer manifestation, and the treatment options need to be guided accordingly. The critical roles played by some of the molecules associated with the signaling pathways and cell microenvironment that often induce tumorigenesis and metastasis have been described precisely in recent years based on findings of the human genome project and other related initiatives undertaken afterward to thoroughly understand the molecular basis of cancer cell behaviors. It is to rely upon the genomic study of cancer cells to fully understand the prognosis and pathways involved in disease progression to selectively target them for a cure. Furthermore, patients with the same cancer types often respond differently to cancer therapies, indicating the need for a patient-specific treatment regimen for cancer. In this direction, precision oncology, defined as the molecular profiling of tumors to identify targetable alterations for custom-tailored personalized treatment, is gaining ground as a potential means of cancer treatment and has started influencing the ways cancer has been treated in clinics. This article intends to comprehensively elucidate the foundations and frontiers of precision oncology in the context of recent advances in cancer genomics and single-cell technologies for assessing its scope and importance in the realization of a proper cure for cancer.
ARTICLE | doi:10.20944/preprints202103.0242.v1
Subject: Life Sciences, Biochemistry Keywords: apoptosis; evading apoptosis; expression variability; cancer functional pathway; prostate cancer phenotype; immortality; proliferation; P53 signaling; transcriptomic network
Online: 9 March 2021 (08:44:15 CET)
Prostate cancer is a leading cause of death among men but its genomic characterization and best therapeutic strategy are still under debate. The Genomic Fabric Paradigm (GFP) considers the transcriptome as a multi-dimensional mathematical object subjected to a dynamic set of expression correlations among the genes. Here, GFP is applied to gene expression profiles of three (one primary, and two secondary) cancer nodules and the surrounding normal tissue from a surgically removed prostate tumor. GFP was used to determine the regulation and rewiring of the P53 signaling, apoptosis, prostate cancer and several other pathways involved in survival and proliferation of the cancer cells. Genes responsible for the block of differentiation, evading apoptosis, immortality, insensitivity to anti-growth signals, proliferation, resistance to chemotherapy and sustained angiogenesis were found as differently regulated in the three cancer nodules with respect to the normal tissue. The analysis indicates that even histo-pathologically equally graded cancer nodules from the same tumor have substantially different transcriptomic organizations, raising legitimate questions about the validity of meta-analyses comparing large populations of healthy and cancer humans. The study suggests that GFP may provide a personalized alternative to the biomarkers’ approach of cancer genomics.
REVIEW | doi:10.20944/preprints202011.0563.v2
Subject: Medicine & Pharmacology, Allergology Keywords: Chromosomal instability; FA pathway; Radial figures; TGF pathway; MYC; p53; Bone marrow failure; cancer; physical abnormalities; infertility.
Online: 22 December 2020 (10:58:20 CET)
Abstract: Fanconi anemia (FA), a chromosomal instability syndrome, is caused by inherited pathogenic variants in any of 22 FANC genes, that cooperate in the FA/BRCA pathway. This pathway regulates the repair of DNA interstrand crosslinks (ICLs) through homologous recombination. In FA proper repair of ICLs is impaired, and accumulation of toxic DNA double strand breaks occurs. In order to repair this type of DNA damage, FA cells activate alternative error-prone DNA repair pathways, that may lead to the formation of gross structural chromosome aberrations of which radial figures are the hallmark of FA and their segregation during cell division are the origin of subsequent aberrations like translocations, dicentrics and acentric fragments. The deficiency in DNA repair has pleiotropic consequences in the phenotype of patients with FA, including developmental alterations, bone marrow failure and an extreme risk to develop cancer. The mechanisms leading to the physical abnormalities during embryonic development have not been clearly elucidated, however FA has features of premature aging with chronic inflammation mediated by pro-inflammatory cytokines, that results in tissue attrition, selection of malignant clones and cancer onset. Moreover, the effect of the FA/BRCA pathway in germinal cells, evidenced by infertility in patients with FA attests of chromosomal instability and cell death also occurring in the germinal compartment.
ARTICLE | doi:10.20944/preprints201908.0182.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: indirubin-3′-monoxime; p53; death receptor 5; TNF-related apoptosis-inducing ligand; transcription factor C/EBP homologous protein
Online: 17 August 2019 (04:19:38 CEST)
Indirubin-3′-monoxime (I3M) exhibits anti-proliferative activity in various cancer cells; however, its anti-cancer mechanism remains incompletely elucidated. This study revealed that I3M promotes the expression of death receptor 5 (DR5) and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) in HCT116 p53+/+ cells, resulting in caspase-mediated apoptosis. However, this study demonstrated that HCT116 p53-/- cells are insensitive to I3M-mediated apoptosis, indicating that I3M-induced apoptosis depends on the p53 status of HCT116 cells. Additionally, in HCT116 p53-/- cells, I3M significantly increased Ras expression, while in HCT116 p53+/+ cells, it reduced Ras expression. Furthermore, I3M remarkably increased the production of reactive oxygen species (ROS), which were reduced in transient p53 knockdown, indicating that I3M-mediated apoptosis is promoted by p53-mediated ROS production. Our results also showed that I3M enhanced transcription factor C/EBP homologous protein (CHOP) expression, resulting in endoplasmic reticulum (ER) stress-mediated DR5 expression, which is upregulated by ROS production in HCT116 p53+/+ cells. Moreover, co-treatment with TRAIL synergistically enhanced I3M-induced DR5 expression, thereby triggering TRAIL-induced apoptosis of HCT116 p53+/+ cells, which was interfered by a DR5-specific blocking chimeric antibody. In summary, I3M potently enhances TRAIL-induced apoptosis by upregulating DR5 expression via p53-mediated ROS production in HCT116 p53+/+ cells. However, HCT116 p53-/- cells were resistant to I3M-mediated apoptosis, suggesting that I3M could be a promising anti-cancer candidate against TRAIL-resistant p53+/+ cancer cells.
ARTICLE | doi:10.20944/preprints202107.0553.v1
Subject: Life Sciences, Biochemistry Keywords: oral squamous cell carcinoma; oral cancer; Brd4; c-Myc; p53; cytology; liquid-based cytology; immunocytochemistry; 4-nitroquinoline 1-oxide
Online: 26 July 2021 (08:19:05 CEST)
Most oral squamous cell carcinomas (OSCCs) arise from oral epithelial dysplasia; however, there is no useful marker for early OSCC detection, likely owing to the inability to continuously observe the carcinoma sequence. We aimed to establish an experimental model to observe changes in the sequential expression pattern of mRNA and protein in the same rat using liquid-based cytology techniques. Cytology specimens were collected from a 4-nitroquinoline 1-oxide-induced rat tongue cancer model at 2, 5, 8, 11, 14, 17, and 21 weeks. We examined candidate biomarker expression using immunocytochemistry and quantitative real-time PCR. The percentage of positively stained nuclei was calculated as the labeling index (LI). All rats had OSCC of the tongue at 21 weeks. Brd4 (Brd4), Myc (c-Myc), and Tp53 (p53) mRNA levels were upregulated during progression from negative for intraepithelial lesion or malignancy to SCC. Brd4- and c-Myc-LI were increased in low- and high-grade squamous intraepithelial lesions and SCC specimens. p53-LI was significantly increased in SCC specimens. Our experimental model allowed the observation of sequential morphological changes and mRNA and protein expression patterns in the same rat during carcinogenesis. By reducing the false negative rate, BRD4 and c-Myc can be useful markers for the early detection of OSCC.
ARTICLE | doi:10.20944/preprints201911.0131.v1
Subject: Biology, Animal Sciences & Zoology Keywords: epitope; monoclonal antibodies; open reading frame 3 protein; apoptosis; p53; porcine circovirus type 2; thimerosal; interfere; antibody binding; lymphocyte
Online: 12 November 2019 (16:20:27 CET)
Porcine circovirus type 2 (PCV2) is a small non-enveloped DNA virus that causes swine immunosuppression by inducing apoptosis in lymphocytes. The ORF3 protein plays a major role in PCV2-induced apoptosis in porcine kidney cells, but there is little information regarding this protein in PCV2-infected lymphocytes. In this study, hybridoma screening and epitope mapping were determined by using an indirect ELISA. The mAb 7D3 against ORF3 peptide (residues 35–65) of PCV2 were generated in this study. In vivo situation, the mAb 7D3 recognized ORF3 protein existed in PCV2-infected apoptotic porcine PBMCs. It is noteworthy that thimerosal interfered with the binding of mAb 7D3 to epitope and it was diminished by adding cysteine. Additionally, thimerosal interacting with cysteine-containing peptide was demonstrated by the PTI assay. Furthermore, thimerosal specifically interacted with the antigen-binding sites of mAb 7D3. This study suggested that thimerosal blockade the occlusion of the antigen-binding sites of mAb 7D3 to bind ORF3 peptide (residues 35–65) via thimerosal interacting with cysteine residues which should be located within the antigen-binding sites of mAb 7D3. Overall, the mAb 7D3 has been characterized and it will be a valuables tool in future studies of ORF3 function and the wider mechanism of cell apoptosis caused by PCV2 infection. Similarly, these techniques will be useful for applications in detecting thimerosal too.
ARTICLE | doi:10.20944/preprints201912.0076.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: H3K27M; DIPG; p53; APR-246; Jumonji family histone demethylases; GSK-J4, radiation; DNA damage repair; glutathione depletion; oxidative stress induction
Online: 6 December 2019 (04:34:45 CET)
Diffuse intrinsic pontine glioma (DIPG) is an aggressive pediatric brainstem tumor with a 5-year survival of <1%. Up to 80% of DIPG tumors contain a specific K27M mutation in one of two genes encoding histone H3 (H3K27M). Furthermore, p53 mutations found in >70-80% of H3K27M DIPG, and mutant p53 status is associated with a decreased response to radiation treatment and worse overall prognosis. Recent evidence indicates that H3K27M mutation disrupts tri-methylation at H3K27 leading to aberrant gene expression. Jumonji family histone demethylases collaborates with H3K27 mutation in DIPG by erasing H3K27 trimethylation and thus contributing to derepression of genes involved in tumorigenesis. Since the first line treatment for pediatric DIPG is fractionated radiation, we investigated the effects of Jumonji demethylase inhibition with GSK-J4, and mutant p53 targeting/oxidative stress induction with APR-246, on radio-sensitization of human H3K27M DIPG cells. Both APR-246 and GSK-J4 displayed growth inhibitory effects as single agents in H3K27M DIPG cells. Furthermore, both of these agents elicited mild radiosensitizing effects in human DIPG cells (sensitizer enhancement ratios (SERs) of 1.12 and 1.35, respectively; p<0.05). Strikingly, a combination of APR-246 and GSK-J4 displayed a significant enhancement of radiosensitization, with SER of 1.50 (p<0.05) at sub-micro-molar concentrations of the drugs (0.5 μM). The molecular mechanism of the observed radiosensitization appears to involve DNA damage repair deficiency triggered by APR-246/GSK-J4, leading to the induction of apoptotic cell death. Thus, a therapeutic approach of combined targeting of mutant p53, oxidative stress induction, and Jumonji demethylase inhibition with radiation in DIPG warrants further investigation.