scholarly journals Astrocytes derived from p53-deficient mice provide a multistep in vitro model for development of malignant gliomas.

1995 ◽  
Vol 15 (8) ◽  
pp. 4249-4259 ◽  
Author(s):  
A M Yahanda ◽  
J M Bruner ◽  
L A Donehower ◽  
R S Morrison
Keyword(s):  
Genomic Instability ◽  
Malignant Transformation ◽  
Nude Mice ◽  
Malignant Gliomas ◽  
Early Event ◽  
Wild Type ◽  
Early Passage ◽  
Wild Type P53

Loss or mutation of p53 is thought to be an early event in the malignant transformation of many human astrocytic tumors. To better understand the role of p53 in their growth and transformation, we developed a model employing cultured neonatal astrocytes derived from mice deficient in one (p53 +/-) or both (p53 -/-) p53 alleles, comparing them with wild-type (p53 +/+) cells. Studies of in vitro and in vivo growth and transformation were performed, and flow cytometry and karyotyping were used to correlate changes in growth with genomic instability. Early-passage (EP) p53 -/- astrocytes achieved higher saturation densities and had more rapid growth than EP p53 +/- and +/+ cells. The EP p53 -/- cells were not transformed, as they were unable to grow in serum-free medium or in nude mice. With continued passaging, p53 -/- cells exhibited a multistep progression to a transformed phenotype. Late-passage p53 -/- cells achieved saturation densities 50 times higher than those of p53 +/+ cells and formed large, well-vascularized tumors in nude mice. p53 +/- astrocytes exhibited early loss of the remaining wild-type p53 allele and then evolved in a manner phenotypically similar to p53 -/- astrocytes. In marked contrast, astrocytes retaining both wild-type p53 alleles never exhibited a transformed phenotype and usually senesced after 7 to 10 passages. Dramatic alterations in ploidy and karyotype occurred and were restricted to cells deficient in wild-type p53 following repeated passaging. The results of these studies suggest that loss of wild-type p53 function promotes genomic instability, accelerated growth, and malignant transformation in astrocytes.

Wild Type p53 Gene Sensitizes Rat C6 Glioma Cells to HSV-TK/ACV Treatment In Vitro and In Vivo

2010 ◽  
Vol 16 (4) ◽  
pp. 509-514 ◽  
Author(s):  
Qiang Huang ◽  
Zhibo Xia ◽  
Yongping You ◽  
Peiyu Pu
Keyword(s):  
Glioma Cells ◽  
P53 Gene ◽  
C6 Glioma ◽  
C6 Glioma Cells ◽  
Wild Type ◽  
Wild Type P53 ◽  
Rat C6 Glioma

scholarly journals A potent CBP/p300-Snail interaction inhibitor suppresses tumor growth and metastasis in wild-type p53-expressing cancer

2020 ◽  
Vol 6 (17) ◽  
pp. eaaw8500
Author(s):  
Hong-Mei Li ◽  
Yan-Ran Bi ◽  
Yang Li ◽  
Rong Fu ◽  
Wen-Cong Lv ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Epithelial Mesenchymal Transition ◽  
Therapeutic Effects ◽  
Creb Binding Protein ◽  
Wild Type ◽  
Mesenchymal Transition ◽  
Patients With Cancer ◽  
Wild Type P53

The zinc finger transcription factor Snail is aberrantly activated in many human cancers and associated with poor prognosis. Therefore, targeting Snail is expected to exert therapeutic benefit in patients with cancer. However, Snail has traditionally been considered “undruggable,” and no effective pharmacological inhibitors have been identified. Here, we found a small-molecule compound CYD19 that forms a high-affinity interaction with the evolutionarily conserved arginine-174 pocket of Snail protein. In aggressive cancer cells, CYD19 binds to Snail and thus disrupts Snail’s interaction with CREB-binding protein (CBP)/p300, which consequently impairs CBP/p300-mediated Snail acetylation and then promotes its degradation through the ubiquitin-proteasome pathway. Moreover, CYD19 restores Snail-dependent repression of wild-type p53, thus reducing tumor growth and survival in vitro and in vivo. In addition, CYD19 reverses Snail-mediated epithelial-mesenchymal transition (EMT) and impairs EMT-associated tumor invasion and metastasis. Our findings demonstrate that pharmacologically targeting Snail by CYD19 may exert potent therapeutic effects in patients with cancer.

scholarly journals Dual inhibition of MDMX and MDM2 as a therapeutic strategy in leukemia

2018 ◽  
Vol 10 (436) ◽  
pp. eaao3003 ◽  
Author(s):  
Luis A. Carvajal ◽  
Daniela Ben Neriah ◽  
Adrien Senecal ◽  
Lumie Benard ◽  
Victor Thiruthuvanathan ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Single Molecule ◽  
Cellular Proliferation ◽  
Wild Type ◽  
Suppressor Activity ◽  
Mouse Double Minute ◽  
Double Minute ◽  
Wild Type P53

The tumor suppressor p53 is often inactivated via its interaction with endogenous inhibitors mouse double minute 4 homolog (MDM4 or MDMX) or mouse double minute 2 homolog (MDM2), which are frequently overexpressed in patients with acute myeloid leukemia (AML) and other cancers. Pharmacological disruption of both of these interactions has long been sought after as an attractive strategy to fully restore p53-dependent tumor suppressor activity in cancers with wild-type p53. Selective targeting of this pathway has thus far been limited to MDM2-only small-molecule inhibitors, which lack affinity for MDMX. We demonstrate that dual MDMX/MDM2 inhibition with a stapled α-helical peptide (ALRN-6924), which has recently entered phase I clinical testing, produces marked antileukemic effects. ALRN-6924 robustly activates p53-dependent transcription at the single-cell and single-molecule levels and exhibits biochemical and molecular biological on-target activity in leukemia cells in vitro and in vivo. Dual MDMX/MDM2 inhibition by ALRN-6924 inhibits cellular proliferation by inducing cell cycle arrest and apoptosis in cell lines and primary AML patient cells, including leukemic stem cell–enriched populations, and disrupts functional clonogenic and serial replating capacity. Furthermore, ALRN-6924 markedly improves survival in AML xenograft models. Our study provides mechanistic insight to support further testing of ALRN-6924 as a therapeutic approach in AML and other cancers with wild-type p53.

scholarly journals Adenovirus mediated p53 tumour suppressor gene therapy for human gastric cancer cells in vitro and in vivo

Gut ◽  
1999 ◽  
Vol 44 (3) ◽  
pp. 366-371 ◽  
Author(s):  
M Ohashi ◽  
F Kanai ◽  
H Ueno ◽  
T Tanaka ◽  
K Tateishi ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Gene Therapy ◽  
P53 Gene ◽  
Human Gastric Cancer ◽  
Wild Type ◽  
Gastric Cancer Cells ◽  
Gastric Cancer Cell Lines ◽  
Wild Type P53

BACKGROUND/AIMSGastric cancer is one of the most prevalent forms of cancer in East Asia. Point mutation of the p53 gene has been reported in more than 60% of cases of gastric cancer and can lead to genetic instability and uncontrolled cell proliferation. The purpose of this investigation was to evaluate the potential of p53 gene therapy for gastric cancer.METHODSThe responses of human gastric cancer cell lines, MKN1, MKN7, MKN28, MKN45, and TMK-1, to recombinant adenoviruses encoding wild type p53 (AdCAp53) were analysed in vitro. The efficacy of the AdCAp53 treatment for MKN1 and MKN45 subcutaneous tumours in nude mice was assessed in vivo.RESULTSp53-specific growth inhibition was observed in vitro in two of four gastric cancer cell lines with mutated p53, but not in the wild type p53 cell line. The mechanism of the killing of gastric cancer cells by AdCAp53 was found, by flow cytometric analysis and detection of DNA fragmentation, to be apoptosis. In vivo studies showed that the growth of subcutaneous tumours of p53 mutant MKN1 cells was significantly inhibited by direct injection of AdCAp53, but no significant growth inhibition was detected in the growth of p53 wild type MKN45 tumours.CONCLUSIONSAdenovirus mediated reintroduction of wild type p53 is a potential clinical utility in gene therapy for gastric cancers.

Effects of Gamma Knife surgery on C6 glioma in combination with adenoviral p53 in vitro and in vivo

2006 ◽  
Vol 105 (Supplement) ◽  
pp. 208-213 ◽  
Author(s):  
Desheng Xu ◽  
Qiang Jia ◽  
Yanhe Li ◽  
Chunsheng Kang ◽  
Peiyu Pu
Keyword(s):  
Glioma Cells ◽  
P53 Gene ◽  
Treated Group ◽  
C6 Glioma ◽  
C6 Glioma Cells ◽  
Survival Duration ◽  
Wild Type ◽  
Wild Type P53

ObjectThe authors sought to study the combined potential of wild-type p53 gene transfer and Gamma Knife surgery (GKS) for the treatment of glioblastomas multiforme. Modification of the radiation response in C6 glioma cells in vitro and in vivo by the wild-type p53 gene was investigated.MethodsStable expression of wild-type p53 in C6 cells was achieved by transduction of the cells with adenoviral p53. Two days later, some cells were treated with GKS. Forty-eight hours after irradiation, the comparative survival rate was assessed by monotetrazolium (MTT) assays. Treated and control C6 glioma cells (4 × 103 per well) were plated into a 96-well plate in octuplicate and tested every 24 hours. Meanwhile, immunohistopathological examination of proliferating cell nuclear antigen (PCNA) and terminal deoxynucleotidyl transferase—mediated deoxyuridine triphosphate (TUNEL) assays were performed. The MTT assays indicated the p53, GKS, and combined treated cells proliferated at a significantly lower rate than those of the control group (p < 0.01, Days 2–6) and the positive fraction of PCNA in p53-treated group and GKS-treated group was 70.18 ± 3.61 and 50.71 ± 2.61, respectively, whereas the percentage in the combined group was 30.68 ± 1.49 (p < 0.01).Fifty-six male Sprague–Dawley rats were anesthetized and inoculated with 106 cultured C6 glioma cells into the cerebrum. Forty-eight hours after transduction with adenoviral p53, some rats underwent GKS. A margin dose of 15 Gy was delivered to the 50% isodose line. Two days later, six rats in each group were killed. Their brains were removed and paraffin-embedded section were prepared for immunohistopathological examination and TUNEL assays. The remaining rats were observed for the duration of the survival period. The survival curve indicated that a modest but significant enhancement of survival duration was seen in the p53-treated or GKS alone groups, whereas a more marked and highly significant enhancement of survival duration was achieved when these two treatment modalities were combined. When PCNA expression was downregulated, apoptotic cells become obvious after TUNEL staining.Conclusions The findings of this study suggest that p53-based gene therapy in combination with GKS may be superior to single-modality treatment of C6 glioma.

scholarly journals The isolation of an RNA aptamer targeting to p53 protein with single amino acid mutation

2015 ◽  
Vol 112 (32) ◽  
pp. 10002-10007 ◽  
Author(s):  
Liang Chen ◽  
Farooq Rashid ◽  
Abdullah Shah ◽  
Hassaan M. Awan ◽  
Mingming Wu ◽  
...  
Keyword(s):  
P53 Protein ◽  
P53 Gene ◽  
P53 Mutation ◽  
Single Amino Acid ◽  
Human Lung Cancer ◽  
Rna Aptamer ◽  
Wild Type ◽  
Wild Type P53

p53, known as a tumor suppressor, is a DNA binding protein that regulates cell cycle, activates DNA repair proteins, and triggers apoptosis in multicellular animals. More than 50% of human cancers contain a mutation or deletion of the p53 gene, and p53R175 is one of the hot spots of p53 mutation. Nucleic acid aptamers are short single-stranded oligonucleotides that are able to bind various targets, and they are typically isolated from an experimental procedure called systematic evolution of ligand exponential enrichment (SELEX). Using a previously unidentified strategy of contrast screening with SELEX, we have isolated an RNA aptamer targeting p53R175H. This RNA aptamer (p53R175H-APT) has a significantly stronger affinity to p53R175H than to the wild-type p53 in both in vitro and in vivo assays. p53R175H-APT decreased the growth rate, weakened the migration capability, and triggered apoptosis in human lung cancer cells harboring p53R175H. Further analysis actually indicated that p53R175H-APT might partially rescue or correct the p53R175H to function more like the wild-type p53. In situ injections of p53R175H-APT to the tumor xenografts confirmed the effects of this RNA aptamer on p53R175H mutation in mice.

scholarly journals Adenovirus-mediated wild-type p53 overexpression inhibits endothelial cell differentiation in vitro and angiogenesis in vivo

Gene Therapy ◽  
1998 ◽  
Vol 5 (6) ◽  
pp. 747-754 ◽  
Author(s):  
T Riccioni ◽  
C Cirielli ◽  
X Wang ◽  
A Passaniti ◽  
MC Capogrossi
Keyword(s):  
Endothelial Cell ◽  
Cell Differentiation ◽  
Wild Type ◽  
P53 Overexpression ◽  
Endothelial Cell Differentiation ◽  
Wild Type P53

USP2a is an oncogenic isopeptidase and a potential target in prostate cancer

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 14522-14522
Author(s):  
C. Priolo ◽  
D. Tang ◽  
M. Brahmandam ◽  
B. Benassi ◽  
E. Sicinska ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Nude Mice ◽  
Fatty Acid Synthase ◽  
Chemotherapeutic Agents ◽  
Human Prostate ◽  
Wild Type ◽  
Normal Prostate ◽  
Prostate Cell

14522 Background: De-ubiquitinating enzymes (isopeptidases) remove ubiquitin side chains prior to degradation by the proteosome thus stabilizing their protein targets. We have identified a novel androgen regulated isopeptidase, USP2a, and demonstrated that it binds and prolongs the half-life of fatty acid synthase (FAS), a key enzyme in lipid metabolism of tumor cells. Methods: We determined whether USP2a has oncogenic properties in vitro and in vivo. Wild-type and catalytically inactive USP2a were introduced in immortalized normal prostate epithelial cells (AR-iPrECs). Clonogenicity assays and apoptosis induction by chemotherapeutic agents were performed on these cells. Anti-USP2a siRNA were transfected in normal and transformed (LNCaP, DU145 and PC-3) prostate cell lines. Oncogenicity in vivo was shown by s.c. injection of NIH3T3-USP2a cells in nude mice. Furthermore, USP2a mRNA expression and gene microarrays were tested in 52 human prostate adenocarcinomas. Results: Wild-type USP2a overexpression in AR-iPrEC cells resulted in a significant increase in number and size of colonies compared to those obtained in parental cells. Growth in soft agar was significantly enhanced as well. Silencing of USP2a in LNCAP and DU145 cells resulted in a strong apoptotic effect, evaluated by FACS analysis and cleaved-PARP expression. The role of this isopeptidase in apoptosis regulation was confirmed on AR-iPrEC-USP2a cells, that showed resistance to apoptosis induced by cisplatin and taxol. Importantly, USP2a overexpression was able to transform NIH3T3 cells, generating greater than or equal to 0.5 cm subcutaneous tumors in 12/12 nude mice within 3 weeks, while none of the negative controls grew. USP2a mRNA was overexpressed in 39% of human prostate cancers, showing 1.6–104 (median 5.48) fold induction relative to normal tissues by qRT-PCR. Gene expression profiling of the same tumors revealed specific signatures in USP2a-overexpressing tumors. Conclusions: Our results demonstrate that USP2a behaves as an oncogene in vitro and in vivo and is overexpressed in organ-confined prostate cancer. These data strongly suggest that this isopeptidase is a potential drug target in prostate cancer. [Table: see text]

scholarly journals The crosstalk between STAT3 and p53/RAS signaling controls cancer cell metastasis and cisplatin resistance via the Slug/MAPK/PI3K/AKT-mediated regulation of EMT and autophagy

Oncogenesis ◽  
2019 ◽  
Vol 8 (10) ◽  
Author(s):  
Fan Liang ◽  
Chunxia Ren ◽  
Jingshu Wang ◽  
Shuoer Wang ◽  
Lina Yang ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Cancer Cell ◽  
Cisplatin Resistance ◽  
Dominant Negative ◽  
Ras Signaling ◽  
Wild Type ◽  
Cell Metastasis ◽  
Wild Type P53

Abstract Chemoresistance has been the biggest obstacle in ovarian cancer treatment, and STAT3 may play an important role in chemoresistance of multiple cancers, but the underlying mechanism of STAT3 in ovarian cancer chemoresistance has long been truly illusive, particularly in association with p53 and RAS signaling. In this study, by using wild type, constitutive active, and dominant negative STAT3 constructs, wild-type p53, and RAS-mutant V12, we performed a series of in vitro and in vivo experiments by gene overexpression, drug treatment, and animal assays. We found that phosphorylation of STAT3 Y705 but not S727 promoted cancer cell EMT and metastasis through the Slug-mediated regulation of E-cadherin and Vimentin. The phosphorylation of STAT3 at Y705 also activated the MAPK and PI3K/AKT signaling to inhibit the ERS-mediated autophagy through down-regulation of pPERK, pelf2α, ATF6α, and IRE1α, which led to increased cisplatin resistance. Induction of wild type p53 in STAT3-DN-transfected cells further diminished the chemoresistance and tumor growth through the upregulation of the MAPK- and PI3K/AKT-mediated ERS and autophagy. Introduction of STAT3-DN deprived the RASV12-induced ERS, autophagy, oncogenicity, and cisplatin resistance, whereas introduction of p53 in STAT3-DN/RASV12 expressing cells induced additional tumor retardation and cisplatin sensitivity. Thus, our data provide strong evidence that the crosstalk between STAT3 and p53/RAS signaling controls ovarian cancer cell metastasis and cisplatin resistance via the Slug/MAPK/PI3K/AKT-mediated regulation of EMT and autophagy.

scholarly journals Tumor suppressor p53: analysis of wild-type and mutant p53 complexes.

1991 ◽  
Vol 11 (1) ◽  
pp. 12-19 ◽  
Author(s):  
J Milner ◽  
E A Medcalf ◽  
A C Cook
Keyword(s):  
Tumor Progression ◽  
Carboxyl Terminus ◽  
Mutant P53 ◽  
Tumor Suppressor P53 ◽  
Wild Type ◽  
Dominant Effect ◽  
Type Mutant ◽  
Wild Type P53

It has been suggested that the dominant effect of mutant p53 on tumor progression may reflect the mutant protein binding to wild-type p53, with inactivation of suppressor function. To date, evidence for wild-type/mutant p53 complexes involves p53 from different species. To investigate wild-type/mutant p53 complexes in relation to natural tumor progression, we sought to identify intraspecific complexes, using murine p53. The mutant phenotype p53-246(0) was used because this phenotype is immunologically distinct from wild-type p53-246+ and thus permits immunological analysis for wild-type/mutant p53 complexes. The p53 proteins were derived from genetically defined p53 cDNAs expressed in vitro and also from phenotypic variants of p53 expressed in vivo. We found that the mutant p53 phenotype was able to form a complex with the wild type when the two p53 variants were cotranslated. When mixed in their native states (after translation), the wild-type and mutant p53 proteins did not exhibit any binding affinity for each other in vitro. Under identical conditions, complexes of wild-type human and murine p53 proteins were formed. For murine p53, both the wild-type and mutant p53 proteins formed high-molecular-weight complexes when translated in vitro. This oligomerization appeared to involve the carboxyl terminus, since truncated p53 (amino acids 1 to 343) did not form complexes. We suggest that the ability of the mutant p53 phenotype to complex with wild type during cotranslation may contribute to the transforming function of activated mutants of p53 in vivo.

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