scholarly journals The Role of p53 Signaling in Colorectal Cancer

Cancers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 2125
Author(s):  
Magdalena C. Liebl ◽  
Thomas G. Hofmann
Keyword(s):  
Colorectal Cancer ◽  
Cancer Progression ◽  
Target Genes ◽  
Tp53 Gene ◽  
Cellular Responses ◽  
Missense Mutations ◽  
Loss Of Function ◽  
Wild Type ◽  
P53 Signaling ◽  
Stress Signals

The transcription factor p53 functions as a critical tumor suppressor by orchestrating a plethora of cellular responses such as DNA repair, cell cycle arrest, cellular senescence, cell death, cell differentiation, and metabolism. In unstressed cells, p53 levels are kept low due to its polyubiquitination by the E3 ubiquitin ligase MDM2. In response to various stress signals, including DNA damage and aberrant growth signals, the interaction between p53 and MDM2 is blocked and p53 becomes stabilized, allowing p53 to regulate a diverse set of cellular responses mainly through the transactivation of its target genes. The outcome of p53 activation is controlled by its dynamics, its interactions with other proteins, and post-translational modifications. Due to its involvement in several tumor-suppressing pathways, p53 function is frequently impaired in human cancers. In colorectal cancer (CRC), the TP53 gene is mutated in 43% of tumors, and the remaining tumors often have compromised p53 functioning because of alterations in the genes encoding proteins involved in p53 regulation, such as ATM (13%) or DNA-PKcs (11%). TP53 mutations in CRC are usually missense mutations that impair wild-type p53 function (loss-of-function) and that even might provide neo-morphic (gain-of-function) activities such as promoting cancer cell stemness, cell proliferation, invasion, and metastasis, thereby promoting cancer progression. Although the first compounds targeting p53 are in clinical trials, a better understanding of wild-type and mutant p53 functions will likely pave the way for novel CRC therapies.

scholarly journals Mutated p53 in HGSC—From a Common Mutation to a Target for Therapy

Cancers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 3465
Author(s):  
Aya Saleh ◽  
Ruth Perets
Keyword(s):  
Cancer Progression ◽  
Target Genes ◽  
P53 Protein ◽  
Genetic Alterations ◽  
Common Mutation ◽  
Missense Mutations ◽  
P53 Expression ◽  
Histologic Subtype ◽  
Tp53 Mutations

Mutations in tumor suppressor gene TP53, encoding for the p53 protein, are the most ubiquitous genetic variation in human ovarian HGSC, the most prevalent and lethal histologic subtype of epithelial ovarian cancer (EOC). The majority of TP53 mutations are missense mutations, leading to loss of tumor suppressive function of p53 and gain of new oncogenic functions. This review presents the clinical relevance of TP53 mutations in HGSC, elaborating on several recently identified upstream regulators of mutant p53 that control its expression and downstream target genes that mediate its roles in the disease. TP53 mutations are the earliest genetic alterations during HGSC pathogenesis, and we summarize current information related to p53 function in the pathogenesis of HGSC. The role of p53 is cell autonomous, and in the interaction between cancer cells and its microenvironment. We discuss the reduction in p53 expression levels in tumor associated fibroblasts that promotes cancer progression, and the role of mutated p53 in the interaction between the tumor and its microenvironment. Lastly, we discuss the potential of TP53 mutations to serve as diagnostic biomarkers and detail some more advanced efforts to use mutated p53 as a therapeutic target in HGSC.

scholarly journals Decreased level of miR-1301 promotes colorectal cancer progression via activation of STAT3 pathway

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Fangfang Yang ◽  
Hua Wang ◽  
Bianbian Yan ◽  
Tong Li ◽  
Lulu Min ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Migration ◽  
Cancer Progression ◽  
Luciferase Assay ◽  
Migration And Invasion ◽  
Loss Of Function ◽  
Aberrant Expression ◽  
Cell Migration And Invasion ◽  
Lovo Cells ◽  
Colorectal Cancer Progression

Abstract The molecular pathogenesis of colorectal cancer (CRC) has been widely investigated in recent years. Accumulating evidence has indicated that microRNA (miRNA) dysregulation participates in the processes of driving CRC initiation and progression. Aberrant expression of miR-1301 has been found in various tumor types. However, its role in CRC remains to be elucidated. In the present study, we identified miR-1301 was enriched in normal colorectal tissues and significantly down-regulated in CRC. Decreased level of miR-1301 strongly correlated with aggressive pathological characteristics, including advanced stage and metastasis. Bioinformatics and dual luciferase assay demonstrated that STAT3 is a direct target of miR-1301. Gain and loss-of-function assays showed that miR-1301 had no effect on cell proliferation. Overexpression of miR-1301 suppressed cell migration and invasion capacity of pSTA3-positive LoVo cells, but not pSTAT3-negative SW480 cells, while inhibition of miR-1301 consistently promoted cell migration and invasion in both cell lines. Additionally, miR-1301 inhibition restored the suppressed migration and invasion of STAT3- knockdown LoVo cells. MiR-1301 functioned as a tumor suppressor to modulate the IL6/STAT3 signaling pathway. In summary, this study highlights the significant role of miR- 1301/STAT3 axis in CRC metastasis.

scholarly journals Keap1 deletion accelerates mutant K-ras/p53-driven cholangiocarcinoma

2020 ◽  
Vol 318 (3) ◽  
pp. G419-G427 ◽  
Author(s):  
Tatsuhide Nabeshima ◽  
Shin Hamada ◽  
Keiko Taguchi ◽  
Yu Tanaka ◽  
Ryotaro Matsumoto ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cancer Progression ◽  
Stress Responses ◽  
Target Genes ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Related Factor ◽  
Loss Of Function ◽  
P53 Expression ◽  
Nrf2 Activation

The activation of the Kelch-like ECH-associated protein 1 (Keap1)-NF-E2-related factor 2 (Nrf2) pathway contributes to cancer progression in addition to oxidative stress responses. Loss-of-function Keap1 mutations were reported to activate Nrf2, leading to cancer progression. We examined the effects of Keap1 deletion in a cholangiocarcinoma mouse model using a mutant K-ras/ p53 mouse. Introduction of the Keap1 deletion into liver-specific mutant K-ras/ p53 expression resulted in the formation of invasive cholangiocarcinoma. Comprehensive analyses of the gene expression profiles identified broad upregulation of Nrf2-target genes such as Nqo1 and Gstm1 in the Keap1-deleted mutant K-ras/ p53 expressing livers, accompanied by upregulation of cholangiocyte-related genes. Among these genes, the transcriptional factor Sox9 was highly expressed in the dysplastic bile duct. The Keap-Nrf2-Sox9 axis might serve as a novel therapeutic target for cholangiocarcinoma. NEW & NOTEWORTHY The Keap1-Nrf2 system has a wide variety of effects in addition to the oxidative stress response in cancer cells. Addition of the liver-specific Keap1 deletion to mice harboring mutant K-ras and p53 accelerated cholangiocarcinoma formation, together with the hallmarks of Nrf2 activation. This process involved the expansion of Sox9-positive cells, indicating increased differentiation toward the cholangiocyte phenotype.

scholarly journals Identifying metastasis-initiating miRNA-target regulations of colorectal cancer from expressional changes in primary tumors

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jongmin Lee ◽  
Hye Kyung Hong ◽  
Sheng-Bin Peng ◽  
Tae Won Kim ◽  
Woo Yong Lee ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Liver Metastasis ◽  
Cancer Progression ◽  
Cancer Biology ◽  
Mirna Target ◽  
Target Genes ◽  
Expression Profiles ◽  
Statistical Significance ◽  
Primary Tumors ◽  
Significant Difference

Abstract Colorectal cancer (CRC) is prevalent with high mortality, with liver metastasis contributing as a major factor that worsens the survival of patients. The roles of miRNAs in CRC have been elucidated, subsequent to recent studies that suggest the involvement of miRNAs in cancer biology. In this study, we compare the miRNA and gene expression profiles of primary tumors between two groups of patients (with and without liver metastasis) to identify the metastasis-initiating microRNA-target gene regulations. Analysis from 33 patients with metastasis and 14 patients without metastasis revealed that 17 miRNAs and their 198 predicted target genes are differentially expressed, where the target genes showed association with cancer progression and metastasis with statistical significance. In order to evaluate the clinical implications of the findings, we classified CRC patients of independent data into two groups based on the identified miRNA-target regulations, where one group was closer to primary tumors with metastasis than the other group. The comparison of survival showed statistically significant difference, thereby implying the roles of the identified miRNA-target regulations in cancer progression and metastasis. The identification of metastasis-initiating miRNA-target regulations in this study will lead to better understanding of the roles of miRNAs in CRC progression.

scholarly journals The Janus Face of p53-Targeting Ubiquitin Ligases

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1656 ◽  
Author(s):  
Qian Hao ◽  
Yajie Chen ◽  
Xiang Zhou
Keyword(s):  
Cancer Progression ◽  
Ubiquitin Ligases ◽  
Tp53 Gene ◽  
Mutant P53 ◽  
E3 Ubiquitin Ligases ◽  
Tumor Suppressor P53 ◽  
Wild Type ◽  
Cell Growth Arrest ◽  
Cancer Cell Survival ◽  
P53 Status

The tumor suppressor p53 prevents tumorigenesis and cancer progression by maintaining genomic stability and inducing cell growth arrest and apoptosis. Because of the extremely detrimental nature of wild-type p53, cancer cells usually mutate the TP53 gene in favor of their survival and propagation. Some of the mutant p53 proteins not only lose the wild-type activity, but also acquire oncogenic function, namely “gain-of-function”, to promote cancer development. Growing evidence has revealed that various E3 ubiquitin ligases are able to target both wild-type and mutant p53 for degradation or inactivation, and thus play divergent roles leading to cancer cell survival or death in the context of different p53 status. In this essay, we reviewed the recent progress in our understanding of the p53-targeting E3 ubiquitin ligases, and discussed the potential clinical implications of these E3 ubiquitin ligases in cancer therapy.

scholarly journals MON-717 Novel GLI2 Mutations Identified in Pediatric Patients with Combined Pituitary Hormone Deficiency: One Gene, Various Genotypes

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Sebastian A Vishnopolska ◽  
Debora Braslavsky ◽  
Ana Claudia Keselman ◽  
Ignacio Bergada ◽  
Roxana M Marino ◽  
...  
Keyword(s):  
Cell Line ◽  
Target Genes ◽  
Hormone Deficiency ◽  
Pituitary Hormone ◽  
Loss Of Function ◽  
Wild Type ◽  
Gfp Expression ◽  
Shh Signaling ◽  
Pituitary Hormone Deficiency ◽  
Combined Pituitary Hormone Deficiency

Abstract Combined pituitary hormone deficiency (CPHD) is an important clinical problem caused by mutations in more than 30 different genes. Six genes in the Sonic Hedgehog (SHH) signalling pathway are reported to cause CPHD. SHH signaling is essential to induce pituitary cell identity in cells of Rathke’s pouch by stimulating expression of the transcription factors Lhx3 and Lhx4. In the absence of SHH signaling, a repressive isoform of the transcription factor GLI2 (Gli-Kruppel family member 2) suppresses gene expression. In the presence of SHH signaling, the activating form of GLI2 gains access to the nucleus and induces expression of downstream target genes. Heterozygous GLI2 loss of function mutations are found in patients with holoprosencephaly (HPE), HPE-like phenotypes associated with pituitary anomalies, and combined pituitary hormone deficiency with or without other extra-pituitary findings. We sought to identify the cause of CPHD in 171 unrelated patients diagnosed with or without extra-pituitary manifestations that were recruited from several Argentinean medical centers. We conducted panel sequencing, and identified GLI2 heterozygous variants that were rare and predicted to be deleterious in two unrelated patients, (p.L761P and p.1404Lfs) and a single, heterozygous, rare, likely deleterious GLI2 variant identified by exome sequencing (p.A203T). p.L761P and p.A203T variants were previously reported as candidates for HPE/CPHD, no functional studies were carried out to determine the effect of the variants on the gene function. We performed functional analysis of these variants using a mammalian cell line (NIH/3T3-CG) previously engineered to be a sensor for SHH signaling. It was stably transfected with a reporter gene that expresses GFP in response to GLI2 activation by a SHH agonist. We modified this cell line to assay GLI2 variants. We created a homozygous knock out of both endogenous Gli2 genes using CRISPR-Cas9 editing, and individual cell clones were selected for loss of GFP expression in response to SHH agonist treatment by FACS. We verified that transfecting the knockout cells with wild type Gli2 restored SHH responsive GFP expression. We assayed the ability of three patient GLI2 variants to rescue GFP expression and SHH agonist responsiveness and found that all three failed to fully rescue to wild type levels. This supports the hypothesis that the GLI2 variants in three CPHD patients are likely pathogenic. Thus, we identified three likely pathogenic GLI2 mutations in CPHD patients from Argentina. The variable phenotype of patients with GLI2 mutations worldwide could be caused by variation in other genes, environmental exposures, maternal effects, and/or epigenetic factors.

scholarly journals NKX2-5 mutations causative for congenital heart disease retain functionality and are directed to hundreds of targets

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Romaric Bouveret ◽  
Ashley J Waardenberg ◽  
Nicole Schonrock ◽  
Mirana Ramialison ◽  
Tram Doan ◽  
...  
Keyword(s):  
Congenital Heart Disease ◽  
Heart Disease ◽  
Regulatory Networks ◽  
Congenital Heart ◽  
Target Genes ◽  
Loss Of Function ◽  
Wild Type ◽  
Interaction Domain ◽  
Ets Proteins ◽  
Gene Regulatory

We take a functional genomics approach to congenital heart disease mechanism. We used DamID to establish a robust set of target genes for NKX2-5 wild type and disease associated NKX2-5 mutations to model loss-of-function in gene regulatory networks. NKX2-5 mutants, including those with a crippled homeodomain, bound hundreds of targets including NKX2-5 wild type targets and a unique set of "off-targets", and retained partial functionality. NKXΔHD, which lacks the homeodomain completely, could heterodimerize with NKX2-5 wild type and its cofactors, including E26 transformation-specific (ETS) family members, through a tyrosine-rich homophilic interaction domain (YRD). Off-targets of NKX2-5 mutants, but not those of an NKX2-5 YRD mutant, showed overrepresentation of ETS binding sites and were occupied by ETS proteins, as determined by DamID. Analysis of kernel transcription factor and ETS targets show that ETS proteins are highly embedded within the cardiac gene regulatory network. Our study reveals binding and activities of NKX2-5 mutations on WT target and off-targets, guided by interactions with their normal cardiac and general cofactors, and suggest a novel type of gain-of-function in congenital heart disease.

scholarly journals A Positive Feedback Loop of lncRNA MIR31HG-miR-361-3p -YY1 Accelerates Colorectal Cancer Progression Through Modulating Proliferation, Angiogenesis, and Glycolysis

2021 ◽  
Vol 11 ◽  
Author(s):  
Tao Guo ◽  
Defeng Liu ◽  
Shihao Peng ◽  
Meng Wang ◽  
Yangyang Li
Keyword(s):  
Colorectal Cancer ◽  
Cancer Progression ◽  
Positive Feedback ◽  
Feedback Loop ◽  
Luciferase Reporter ◽  
Loss Of Function ◽  
Positive Feedback Loop ◽  
Related Proteins

BackgroundColorectal cancer (CRC) is a common malignant tumor with high metastatic and recurrent rates. This study probes the effect and mechanism of long non-coding RNA MIR31HG on the progression of CRC cells.Materials and MethodsQuantitative real-time PCR (qRT-PCR) was used to analyze the expression of MIR31HG and miR-361-3p in CRC tissues and normal tissues. Gain- or loss-of-function assays were conducted to examine the roles of MIR31HG, miR-361-3p and YY1 transcription factor (YY1) in the CRC progression. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and colony formation experiment were conducted to test CRC cell proliferation. CRC cell invasion was determined by Transwell assay. The glucose detection kit and lactic acid detection kit were utilized to monitor the levels of glucose and lactate in CRC cells. The glycolysis level in CRC cells was examined by the glycolytic stress experiment. Western blot was performed to compare the expression of glycolysis-related proteins (PKM2, GLUT1 and HK2) and angiogenesis-related proteins (including VEGFA, ANGPT1, HIF1A and TIMP1) in HUVECs. The binding relationships between MIR31HG and miR-361-3p, miR-361-3p and YY1 were evaluated by the dual-luciferase reporter assay and RNA immunoprecipitation (RIP).ResultsMIR31HG was up-regulated in CRC tissues and was associated with poorer prognosis of CRC patients. The in-vitro and in-vivo experiments confirmed that overexpressing MIR31HG heightened the proliferation, growth, invasion, glycolysis and lung metastasis of CRC cells as well as the angiogenesis of HUVECs. In addition, MIR3HG overexpression promoted YY1 mRNA and protein level, and forced overexpression of YY1 enhanced MIR31HG level. Overexpressing YY1 reversed the tumor-suppressive effect mediated by MIR31HG knockdown. miR-361-3p, which was inhibited by MIR31HG overexpression, repressed the malignant behaviors of CRC cells. miR-361-3p-mediated anti-tumor effects were mostly reversed by upregulating MIR31HG. Further mechanism studies illustrated that miR-361-3p targeted and negatively regulated the expression of YY1.ConclusionThis study reveals that MIR31HG functions as an oncogenic gene in CRC via forming a positive feedback loop of MIR31HG-miR-361-3p-YY1.

scholarly journals Differential Transcriptional Reprogramming by Wild Type and Lymphoma-Associated Mutant MYC Proteins as B-Cells Convert to a Lymphoma Phenotype

Cancers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 6093
Author(s):  
Amir Mahani ◽  
Gustav Arvidsson ◽  
Laia Sadeghi ◽  
Alf Grandien ◽  
Anthony P. H. Wright
Keyword(s):  
B Cells ◽  
Target Genes ◽  
Cell System ◽  
Integrated Analysis ◽  
Missense Mutations ◽  
Wild Type ◽  
Lymphoma Cells ◽  
Vast Number ◽  
Number Of Genes ◽  
Transformation Activity

The MYC transcription factor regulates a vast number of genes and is implicated in many human malignancies. In some hematological malignancies, MYC is frequently subject to missense mutations that enhance its transformation activity. Here, we use a novel murine cell system to (i) characterize the transcriptional effects of progressively increasing MYC levels as normal primary B-cells transform to lymphoma cells and (ii) determine how this gene regulation program is modified by lymphoma-associated MYC mutations (T58A and T58I) that enhance its transformation activity. Unlike many previous studies, the cell system exploits primary B-cells that are transduced to allow regulated MYC expression under circumstances where apoptosis and senescence pathways are abrogated by the over-expression of the Bcl-xL and BMI1 proteins. In such cells, transition from a normal to a lymphoma phenotype is directly dependent on the MYC expression level, without a requirement for secondary events that are normally required during MYC-driven oncogenic transformation. A generalized linear model approach allowed an integrated analysis of RNA sequencing data to identify regulated genes in relation to both progressively increasing MYC level and wild type or mutant status. Using this design, a total of 7569 regulated genes were identified, of which the majority (n = 7263) were regulated in response to progressively increased levels of wild type MYC, while a smaller number of genes (n = 917) were differentially regulated, compared to wild type MYC, in T58A MYC- and/or T58I MYC-expressing cells. Unlike most genes that are similarly regulated by both wild type and mutant MYC genes, the set of 917 genes did not significantly overlap with known lipopolysaccharide regulated genes, which represent genes regulated by MYC in normal B cells. The genes that were differently regulated in cells expressing mutant MYC proteins were significantly enriched in DNA replication and G2 phase to mitosis transition genes. Thus, mutants affecting MYC proteins may augment quantitative oncogenic effects on the expression of normal MYC-target genes with qualitative oncogenic effects, by which sets of cell cycle genes are abnormally targeted by MYC as B cells transition into lymphoma cells. The T58A and T58I mutations augment MYC-driven transformation by distinct mechanisms.

scholarly journals P53 and the Carcinoma of the Breast: A Review

2020 ◽  
Vol 3 (1) ◽  
pp. 97-102
Author(s):  
Sujan Narayan Agrawal ◽  
Anuradha Nayak
Keyword(s):  
Target Genes ◽  
Dna Recombination ◽  
Tp53 Gene ◽  
P53 Mutation ◽  
Dominant Negative ◽  
Chromosome Band ◽  
Breast Cancers ◽  
Loss Of Function ◽  
P53 Family ◽  
Regulatory Pathways

TP53 is a gene and p53 is its product protein. Since its discovery many studies have looked into its function and its role in cancer. It is not   only involved in the induction of apoptosis but is also, a key player, in cell cycle regulation, development, differentiation, gene amplification, DNA recombination, chromosomal segregation and cellular senescence and so, it is called “the guardian of genome”. The human TP53 gene spans 20kb on chromosome band 17p13.1. The biological functions of p53 are apoptosis, senescence and cell migration. The evolution of a normal cell towards a cancerous one is a complex process. Tumorogenesis is considered to endow, the evolving tumor with, self-sufficiency of growth signals, insensitivity to antigrowth signals, evasion from programmed cell death, unlimited replicative potentials and finally the ability to invade and metastasize. TP53 may be considered as the “ultimate tumor suppressor gene”. Its oncogenic activity is attributed to loss of function, dominant negative (DN) oncogenic properties and activities of mutant p53. In breast cancer its oncogenic function is due to p53 mutation, changes in- upstream regulatory pathways, in p53 transcriptional target genes, in p53 co-activators, and/or involvement of other family members of p53 family like p63 and p73. The p53 mutation is present in only in about 20% of breast cancers, but when present, they entail the worst prognosis. This interesting paper is a review and discussion about role of p53 in carcinoma breast.

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