BTG4 is A Novel p53 Target Gene That Inhibits Cell Growth and Induces Apoptosis

PHLDA1 is a P53 target gene involved in P53-mediated cell apoptosis

Pleckstrin homeolike domain, family A, member 1 (PHLDA1) is a multifunctional protein that plays diverse roles in A variety of biological processes, including cell death, and hence its altered expression has been found in different types of cancer. Although studies have shown a regulatory relationship between p53 and PHLDA1, the molecular mechanism is still unclear. Especially, the role of PHLDA1 in the process of apoptosis is still controversial. In this study, we found that the expression of PHLDA1 in human cervical cancer cell lines was correlated with the up-expression of p53 after treatment with apoptosis-inducing factors. Subsequently, the binding site and the binding effect of p53 on the promoter region of PHLDA1 were verified by our bioinformatics data analysis and luciferase reporter assay. Indeed, we used CRISPR-Cas9 to knockout the p53 gene in HeLa cells and further confirmed that p53 can bind to the promoter region of PHLDA1 gene, and then directly regulate the expression of PHLDA1 by recruiting P300 and CBP to change the acetylation and methylation levels in the promoter region. Finally, a series of gain-of-function experiments further confirmed that p53 re-expression in HeLap53-/- cell can up-regulate the reduction of PHLDA1 caused by p53 knockout, and affect cell apoptosis and proliferation. Our study is the first to explore the regulatory mechanism of p53 on PHLDA1 by using the p53 gene knockout cell model, which further proves that PHLDA1 is a target-gene in p53-mediated apoptosis, and reveals the important role of PHLDA1 in cell fate determination.

Genetic mechanisms of fertilization failure and early embryonic arrest: a comprehensive review

BACKGROUND

Infertility and pregnancy loss are longstanding problems. Successful fertilization and high-quality embryos are prerequisites for an ongoing pregnancy. Studies have proven that every stage in the human reproductive process is regulated by multiple genes and any problem, at any step, may lead to fertilization failure (FF) or early embryonic arrest (EEA). Doctors can diagnose the pathogenic factors involved in FF and EEA by using genetic methods. With the progress in the development of new genetic technologies, such as single-cell RNA analysis and whole-exome sequencing, a new approach has opened up for us to directly study human germ cells and reproductive development. These findings will help us to identify the unique mechanism(s) that leads to FF and EEA in order to find potential treatments.

OBJECTIVE AND RATIONALE

The goal of this review is to compile current genetic knowledge related to FF and EEA, clarifying the mechanisms involved and providing clues for clinical diagnosis and treatment.

SEARCH METHODS

PubMed was used to search for relevant research articles and reviews, primarily focusing on English-language publications from January 1978 to June 2023. The search terms included fertilization failure, early embryonic arrest, genetic, epigenetic, whole-exome sequencing, DNA methylation, chromosome, non-coding RNA, and other related keywords. Additional studies were identified by searching reference lists. This review primarily focuses on research conducted in humans. However, it also incorporates relevant data from animal models when applicable. The results were presented descriptively, and individual study quality was not assessed.

OUTCOMES

A total of 233 relevant articles were included in the final review, from 3925 records identified initially. The review provides an overview of genetic factors and mechanisms involved in the human reproductive process. The genetic mutations and other genetic mechanisms of FF and EEA were systematically reviewed, for example, globozoospermia, oocyte activation failure, maternal effect gene mutations, zygotic genome activation abnormalities, chromosome abnormalities, and epigenetic abnormalities. Additionally, the review summarizes progress in treatments for different gene defects, offering new insights for clinical diagnosis and treatment.

WIDER IMPLICATIONS

The information provided in this review will facilitate the development of more accurate molecular screening tools for diagnosing infertility using genetic markers and networks in human reproductive development. The findings will also help guide clinical practice by identifying appropriate interventions based on specific gene mutations. For example, when an individual has obvious gene mutations related to FF, ICSI is recommended instead of IVF. However, in the case of genetic defects such as phospholipase C zeta1 (PLCZ1), actin-like7A (ACTL7A), actin-like 9 (ACTL9), and IQ motif-containing N (IQCN), ICSI may also fail to fertilize. We can consider artificial oocyte activation technology with ICSI to improve fertilization rate and reduce monetary and time costs. In the future, fertility is expected to be improved or restored by interfering with or supplementing the relevant genes.

A pan-cancer analysis of anti-proliferative protein family genes for therapeutic targets in cancer

The recently discovered APRO (anti-proliferative protein) family encodes a group of trans-membrane glycoproteins and includes 6 members: TOB1, TOB2, BTG1, BTG2, BTG3 and BTG4. The APRO family is reportedly associated with the initiation and progression of cancers. This study aims to undertake a comprehensive investigation of the APRO family of proteins as a prognostic biomarker in various human tumors. We performed a pan-cancer analysis of the APRO family based on The Cancer Genome Atlas (TCGA). With the bioinformatics methods, we explored the prognostic value of the APRO family and the correlation between APRO family expression and tumor mutation burden (TMB), microsatellite instability (MSI), drug sensitivity, and immunotherapy in numerous cancers. Our results show that the APRO family was primarily down-regulated in cancer samples. The expression of APRO family members was linked with patient prognosis. In addition, APRO family genes showed significant association with immune infiltrate subtypes, tumor microenvironment, and tumor cell stemness. Finally, our study also demonstrated the relationship between APRO family genes and drug sensitivity. This study provides comprehensive information to understand the APRO family's role as an oncogene and predictor of survival in some tumor types.

Bioinformatic analysis of the clinicopathological and prognostic significance of oocyte-arresting BTG4 mRNA expression in gynecological cancers

BTG4 arrests the cell cycle and suppresses oocyte and embryonic development. We performed a bioinformatic analysis of BTG4 expression. BTG4 expression was downregulated in breast cancer compared with normal tissues (p < .05), but the opposite was observed in cervical, endometrial and ovarian cancers (p < .05). BTG4 methylation was negatively correlated with its mRNA expression in breast, cervical and endometrial cancers (p < .05). BTG4 mRNA expression was negatively correlated with T staging and distant metastasis of breast cancer; and with tumor invasion, clinical stage, low weight and BMI, low histological grade and no diabetes in endometrial cancer but positively with T stage and non-keratinizing squamous carcinoma in endometrial cancer. BTG4 expression was negatively correlated with the survival of ovarian cancer patients (p < .05), but positively for breast, cervical and endometrial cancers (p < .05). BTG4 expression is thus a potential marker reflecting the carcinogenesis, aggressiveness and prognosis in gynecological cancers.Impact StatementWhat is already known on this subject? Previous studies have revealed the structure and location of BTG4. BTG4 inhibit cell proliferative, promote apoptosis, induce G1 cell cycle arrest. BTG4 promotes the development of mouse embryos from cell stage 1 to 2. The methylation and biological function of BTG4 were clarified in gastric and/or colorectal cancer cells.What do the results of this study add? BTG4 is found to closely link to reflect the carcinogenesis, histogenesis, aggressive behaviors and prognosis of gynecological cancers, and involved in ligand-receptor interaction, microtubule motor activity, dynein light chain binding, cilium organization, assembly, and movement in endometrial and ovarian cancers.What are the implications of these finding for clinical practice and/or further research? Aberrant BTG4 mRNA expression can be employed as a marker of the tumorigenesis, histogenesis, aggressiveness and prognosis of gynecological cancers in the future practice and guide the investigation of BTG4-related signal pathways.

Diepoxybutane induces the p53-dependent transactivation of the CCL4 gene that mediates apoptosis in exposed human lymphoblasts

Diepoxybutane (DEB) is the most toxic metabolite of the environmental chemical 1,3-butadiene. We previously demonstrated the occurrence of DEB-induced p53-mediated apoptosis in human lymphoblasts. The p53 protein functions as a master transcriptional regulator in orchestrating the genomic response to a variety of stress signals. Transcriptomic analysis indicated that C-C chemokine ligand 4 (CCL4) gene expression was elevated in a p53-dependent manner in DEB-exposed p53-proficient TK6 cells, but not in DEB-exposed p53-deficient NH32 cells. Thus, the objective of this study was to determine whether the CCL4 gene is a transcriptional target of p53 and deduce its role in DEB-induced apoptosis in human lymphoblasts. Endogenous and exogenous wild-type p53 transactivated the activity of the CCL4 promoter in DEB-exposed lymphoblasts, but mutant p53 activity on this promoter was reduced by ∼80% under the same experimental conditions. Knockdown of the upregulated CCL4 mRNA levels in p53-proficient TK6 cells inhibited DEB-induced apoptosis by ∼45%-50%. Collectively, these observations demonstrate for the first time that the CCL4 gene is upregulated by wild-type p53 at the transcriptional level, and this upregulation mediates apoptosis in DEB-exposed human lymphoblasts.

Cell cycle dysregulation with overexpression of KIF2C/MCAK is a critical event in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a common malignant carcinoma of the head and neck, and the biological mechanisms underlying the pathogenesis of NPC remain not fully understood. In the present study, we systematically analyzed four independent NPC transcriptomic datasets and focused on identifying the critical molecular networks and novel key hub genes implicated in NPC. We found totally 170 common overlapping differentially expressed genes (DEGs) in the four NPC datasets. GO and KEGG pathway analysis revealed that cell cycle dysregulation is a critical event in NPC. Protein-protein interaction (PPI) network analysis identified a 15 hub-gene core network with overexpressed kinesin family member 2C (KIF2C) as a central regulator. Loss-of-function study demonstrated that knockdown of KIF2C significantly inhibited cell growth and cell motility, and delayed cell cycle progression, accompanied with dramatic mitotic defects in spindle formation in NPC cells. RNA-seq analysis revealed that KIF2C knockdown led to deregulation of various downstream genes. KIF2C could also regulate the AKT/mTOR pathways, and enhance paclitaxel sensitivity in NPC cells. Taken together, our results suggest that cell cycle dysregulation is a critical event during NPC pathogenesis and KIF2C is a novel key mitotic hub gene with therapeutic potential in NPC.

Isoforms of the p53 Family and Gastric Cancer: A Ménage à Trois for an Unfinished Affair

Simple Summary

The p53 family is a complex family of transcription factors with different cellular functions that are involved in several physiological processes. A massive amount of data has been accumulated on their critical role in the tumorigenesis and the aggressiveness of cancers of different origins. If common features are observed, there are numerous specificities that may reflect particularities of the tissues from which the cancers originated. In this regard, gastric cancer tumorigenesis is rather remarkable, as it is induced by bacterial and viral infections, various chemical carcinogens, and familial genetic alterations, which provide an example of the variety of molecular mechanisms responsible for cell transformation and how they impact the p53 family. This review summarizes the knowledge gathered from over 40 years of research on the role of the p53 family in gastric cancer, which still displays one of the most elevated mortality rates amongst all types of cancers.

Abstract

Gastric cancer is one of the most aggressive cancers, with a median survival of 12 months. This illustrates its complexity and the lack of therapeutic options, such as personalized therapy, because predictive markers do not exist. Thus, gastric cancer remains mostly treated with cytotoxic chemotherapies. In addition, less than 20% of patients respond to immunotherapy. TP53 mutations are particularly frequent in gastric cancer (±50% and up to 70% in metastatic) and are considered an early event in the tumorigenic process. Alterations in the expression of other members of the p53 family, i.e., p63 and p73, have also been described. In this context, the role of the members of the p53 family and their isoforms have been investigated over the years, resulting in conflicting data. For instance, whether mutations of TP53 or the dysregulation of its homologs may represent biomarkers for aggressivity or response to therapy still remains a matter of debate. This uncertainty illustrates the lack of information on the molecular pathways involving the p53 family in gastric cancer. In this review, we summarize and discuss the most relevant molecular and clinical data on the role of the p53 family in gastric cancer and enumerate potential therapeutic innovative strategies.

Auto-antibodies against apolipoprotein A-1 block cancer cells proliferation and induce apoptosis

Auto-antibodies against apoA-1 (anti-apoA-1 IgGs) have been identified as important actors of atherosclerosis development through pro-inflammatory and pro-atherogenic properties and to also induce apoptosis in tumoral neuronal and lymphocyte derived cell lines through unknown mechanisms. The purpose of this study was to explore the cellular pathways involved in tumoral cell survival modulated by anti-apoA-1 antibodies. We observed that anti-apoA-1 antibodies induce growth arrest (in G2/M phase) and cell apoptosis through caspase 3 activation, accompanied by a selective p53 phosphorylation on serine 15. RNA sequencing indicated that anti-apoA-1 IgGs affect the expression of more than 950 genes belonging to five major groups of genes and respectively involved in i) cell proliferation inhibition, ii) p53 stabilisation and regulation, iii) apoptosis regulation, iv) inflammation regulation, and v) oxidative stress. In conclusion, anti-apoA-1 antibodies seem to have a role in blocking tumoral cell proliferation and survival, by activating a major tumor suppressor protein and by modulating the inflammatory and oxidative stress response. Further investigations are needed to explore a possible anti-cancer therapeutic approach of these antibodies in very specific and circumscribed conditions.

The Role of Long Non-Coding RNAs in Intracranial Aneurysms and Subarachnoid Hemorrhage

Intracranial aneurysms (IAs) represent the most complex and relevant problem of modern neurology and neurosurgery. They serve as one of the main causes of non-traumatic subarachnoid hemorrhage (SAH), causing up to 85% of all cases of intracranial hemorrhage, which is associated with frequent disability and high mortality among patients. Unfortunately, the molecular mechanisms of the development and rupture of IAs are still under study. Long non-coding RNAs (lncRNAs) are non-coding RNAs that typically have a length of more than 200 nucleotides. It is known that lncRNAs regulate many processes, such as transcription, translation, cell differentiation, regulation of gene expression, and regulation of the cell cycle. In recent years, a lot of evidence has established their role in human diseases from oncology to cardiovascular disease. Recent studies have shown that lncRNAs may be involved in the pathogenesis of IAs. The study of lncRNAs and its targets in various pathological conditions of a person is a rapidly developing field, and it is likely that the knowledge obtained from these studies regarding the pathogenesis of intracranial aneurysms will have the potential to use lncRNAs in therapy, as well as in the diagnosis and prediction of high aneurysms risk of rupture.