Metabolic regulation by p53 family members

STEAP3 Affects Ferroptosis and Progression of Renal Cell Carcinoma Through the p53/xCT Pathway

Renal cell carcinoma is particularly sensitive to ferroptosis, an iron-dependent non-apoptotic form of cell death. This mechanism does not require activation of caspase or the participation of other apoptotic effector molecules (such as BAX or BAK), nor is it accompanied by the morphological characteristics or biochemical processes of apoptosis. The STEAP3 gene was found because it promotes tumor apoptosis in prostate cancer, but its role in renal cell carcinoma has not been studied in depth. Through real-time quantitative polymerase chain reaction, we found that the expression of the STEAP3 gene was upregulated in renal cell carcinoma tissue samples and cell lines, and it was found to be highly expressed in renal cell carcinoma tissue through immunohistochemistry. This upregulation is related to poor survival and prognosis of patients. We used erastin, a ferroptosis inducer, found that renal cell carcinoma became more susceptible to ferroptosis after knocking down STEAP3. The results indicate that renal cell carcinoma cell lines with knocked down STEAP3 expression are more sensitive to ferroptosis, and this effect occurs through the p53/xCT pathway. In summary, our research helps to identify new biomarkers and provides new targets for the treatment of renal cell carcinoma.

Chlorogenic acid alleviates thioacetamide-induced toxicity and promotes liver development in zebrafish (Danio rerio) through the Wnt signaling pathway

Chlorogenic acid (CGA) is a phenylpropanoid compound that is well known to improve the antioxidant capacity and other biological activities. However, the roles of CGA in the liver development of organisms are unclear. In the present study, we aimed to investigate the function of CGA in the hepatic development in thioacetamide (TAA)-induced zebrafish embryos. We found that CGA exerted certain beneficial effects on zebrafish larvae from TAA-exposed zebrafish embryos, such as increasing the liver size, body length, heart rate, acetylcholinesterase activity, and motor ability. In addition, CGA displayed an antioxidant effect on TAA-induced zebrafish embryos by enhancing the activities of superoxide dismutase (SOD), catalase (CAT), and glucose-6-phosphate dehydrogenase (G6PDH), and decreasing of the contents of malondialdehyde (MDA), reactive oxygen species (ROS), and nitric oxide (NO). The results of western blotting analysis showed that CGA inhibited cell apoptosis by increasing the levels of Bcl2 apoptosis regulator and decreasing the levels of Bcl2 associated X (Bax), apoptosis regulator and tumor protein P53. Moreover, CGA promoted cell proliferation in TAA-induced zebrafish larvae, as detected using proliferating cell nuclear antigen fluorescence immunostaining. In addition, CGA inhibited the expression of Wnt signaling pathway genes Dkk1 (encoding Dickkopf Wnt signaling pathway inhibitors), and promoted the expression of Lef1 (encoding lymphoid enhancer binding factor 1) and Wnt2bb (encoding wingless-type MMTV integration site family, member 2Bb). When the Wnt signal inhibitor IWR-1 was added, there was no significant change in liver development in the IWR-1 + TAA group compared with the IWR-1 + TAA + CGA group (p <0.05), which suggested that CGA regulates liver development via Wnt signaling pathway. Overall, our results suggested that CGA might alleviate TAA-induced toxicity in zebrafish and promote liver development through the Wnt signaling pathway, which provides a basis for the therapeutic effect of CGA on liver dysplasia.

Ferroptosis: The Silver Lining of Cancer Therapy

Regulatory cell death has been a major focus area of cancer therapy research to improve conventional clinical cancer treatment (e.g. chemotherapy and radiotherapy). Ferroptosis, a novel form of regulated cell death mediated by iron-dependent lipid peroxidation, has been receiving increasing attention since its discovery in 2012. Owing to the highly iron-dependent physiological properties of cancer cells, targeting ferroptosis is a promising approach in cancer therapy. In this review, we summarised the characteristics of ferroptotic cells, associated mechanisms of ferroptosis occurrence and regulation and application of the ferroptotic pathway in cancer therapy, including the use of ferroptosis in combination with other therapeutic modalities. In addition, we presented the challenges of using ferroptosis in cancer therapy and future perspectives that may provide a basis for further research.

Clinical and prognostic implications of an immune-related risk model based on TP53 status in lung adenocarcinoma

TP53 mutation is the most widespread mutation in lung adenocarcinoma (LUAD). Meanwhile, p53 (encoded by TP53) has recently been implicated in immune responses. However, it is still unknown whether TP53 mutation remodels the tumour microenvironment to influence tumour progression and prognosis in LUAD. In this study, we developed a 6‐gene immune‐related risk model (IRM) to predict the survival of patients with LUAD in The Cancer Genome Atlas (TCGA) cohort based on TP53 status, and the predictive ability was confirmed in 2 independent cohorts. TP53 mutation led to a decreased immune response in LUAD. Further analysis revealed that patients in the high‐index group had observably lower relative infiltration of memory B cells and regulatory T cells and significantly higher relative infiltration of neutrophils and resting memory CD4⁺ T cells. Additionally, the IRM index positively correlated with the expression of critical immune checkpoint genes, including PDCD1 (encoding PD‐1) and CD274 (encoding PD‐L1), which was validated in the Nanjing cohort. Furthermore, as an independent prognostic factor, the IRM index was used to establish a nomogram for clinical application. In conclusion, this IRM may serve as a powerful prognostic tool to further optimize LUAD immunotherapy.

Caulerpin Mitigates Helicobacter pylori-Induced Inflammation via Formyl Peptide Receptors

The identification of novel strategies to control Helicobacter pylori (Hp)-associated chronic inflammation is, at present, a considerable challenge. Here, we attempt to combat this issue by modulating the innate immune response, targeting formyl peptide receptors (FPRs), G-protein coupled receptors that play key roles in both the regulation and the resolution of the innate inflammatory response. Specifically, we investigated, in vitro, whether Caulerpin—a bis-indole alkaloid isolated from algae of the genus Caulerpa—could act as a molecular antagonist scaffold of FPRs. We showed that Caulerpin significantly reduces the immune response against Hp culture filtrate, by reverting the FPR2-related signaling cascade and thus counteracting the inflammatory reaction triggered by Hp peptide Hp(2–20). Our study suggests Caulerpin to be a promising therapeutic or adjuvant agent for the attenuation of inflammation triggered by Hp infection, as well as its related adverse clinical outcomes.

Autophagy and apoptosis cascade: which is more prominent in neuronal death?

Autophagy and apoptosis are two crucial self-destructive processes that maintain cellular homeostasis, which are characterized by their morphology and regulated through signal transduction mechanisms. These pathways determine the fate of cellular organelle and protein involved in human health and disease such as neurodegeneration, cancer, and cardiovascular disease. Cell death pathways share common molecular mechanisms, such as mitochondrial dysfunction, oxidative stress, calcium ion concentration, reactive oxygen species, and endoplasmic reticulum stress. Some key signaling molecules such as p53 and VEGF mediated angiogenic pathway exhibit cellular and molecular responses resulting in the triggering of apoptotic and autophagic pathways. Herein, based on previous studies, we describe the intricate relation between cell death pathways through their common genes and the role of various stress-causing agents. Further, extensive research on autophagy and apoptotic machinery excavates the implementation of selective biomarkers, for instance, mTOR, Bcl-2, BH3 family members, caspases, AMPK, PI3K/Akt/GSK3β, and p38/JNK/MAPK, in the pathogenesis and progression of neurodegenerative diseases. This molecular phenomenon will lead to the discovery of possible therapeutic biomolecules as a pharmacological intervention that are involved in the modulation of apoptosis and autophagy pathways. Moreover, we describe the potential role of micro-RNAs, long non-coding RNAs, and biomolecules as therapeutic agents that regulate cell death machinery to treat neurodegenerative diseases. Mounting evidence demonstrated that under stress conditions, such as calcium efflux, endoplasmic reticulum stress, the ubiquitin-proteasome system, and oxidative stress intermediate molecules, namely p53 and VEGF, activate and cause cell death. Further, activation of p53 and VEGF cause alteration in gene expression and dysregulated signaling pathways through the involvement of signaling molecules, namely mTOR, Bcl-2, BH3, AMPK, MAPK, JNK, and PI3K/Akt, and caspases. Alteration in gene expression and signaling cascades cause neurotoxicity and misfolded protein aggregates, which are characteristics features of neurodegenerative diseases. Excessive neurotoxicity and misfolded protein aggregates lead to neuronal cell death by activating death pathways like autophagy and apoptosis. However, autophagy has a dual role in the apoptosis pathways, i.e., activation and inhibition of the apoptosis signaling. Further, micro-RNAs and LncRNAs act as pharmacological regulators of autophagy and apoptosis cascade, whereas, natural compounds and chemical compounds act as pharmacological inhibitors that rescue neuronal cell death through inhibition of apoptosis and autophagic cell death.

Adipose MDM2 regulates systemic insulin sensitivity

The intimate association between obesity and type II diabetes urges for a deeper understanding of adipocyte function. We and others have previously delineated a role for the tumor suppressor p53 in adipocyte biology. Here, we show that mice haploinsufficient for MDM2, a key regulator of p53, in their adipose stores suffer from overt obesity, glucose intolerance, and hepatic steatosis. These mice had decreased levels of circulating palmitoleic acid [non-esterified fatty acid (NEFA) 16:1] concomitant with impaired visceral adipose tissue expression of Scd1 and Ffar4. A similar decrease in Scd and Ffar4 expression was found in in vitro differentiated adipocytes with perturbed MDM2 expression. Lowered MDM2 levels led to nuclear exclusion of the transcriptional cofactors, MORC2 and LIPIN1, and thereby possibly hampered adipocyte function by antagonizing LIPIN1-mediated PPARγ coactivation. Collectively, these data argue for a hitherto unknown interplay between MDM2 and MORC2/LIPIN1 involved in balancing adipocyte function.

Investigation of Prognostic Markers of Lung Adenocarcinoma Based on Tumor Metabolism-Related Genes

Lung adenocarcinoma (LUAD) is a prevalent cancer killer. Investigation on potential prognostic markers of LUAD is crucial for a patient’s postoperative planning. LUAD-associated datasets were acquired from Gene Expression Omnibus (GEO) as well as The Cancer Genome Atlas (TCGA). LUAD metabolism-associated differentially expressed genes were obtained, combining tumor metabolism-associated genes. COX regression analyses were conducted to build a five-gene prognostic model. Samples were divided into high- and low-risk groups by the established model. Survival analysis displayed favorable prognosis in the low-risk group in the training set. Favorable predictive performance of the model was discovered as hinted by receiver’s operative curve (ROC). Survival analysis and ROC analysis in the validation set held an agreement. Gene Set Enrichment Analysis (GSEA), tumor mutation bearing (TMB), and immune infiltration differential analysis were performed. The two groups displayed differences in glycolysis gluconeogenesis, P53 signaling pathway, etc. The high-risk group showed higher TP53 mutation frequency as well as TMB. The low-risk group displayed higher immune activity along with immune score. Altogether, this study casts light on further development of novel prognostic markers for LUAD.

Mutant p53 Attenuates Oxidative Phosphorylation and Facilitates Cancer Stemness through Downregulating miR-200c-PCK2 Axis in Basal-Like Breast Cancer

miR-200c is a tumor suppressor miRNA that plays a critical role in regulating epithelial phenotype and cancer stemness. p53 deficiency downregulates the expression of miR-200c and leads to epithelial-mesenchymal transition (EMT) and stemness phenotype, which contributes to the progression of breast cancers. In this study, we demonstrated that CRISPR-mediated knockout (KO) of miR-200c induces metabolic features similar to the metabolic rewiring caused by p53 hot-spot mutations, and that impairing this metabolic reprogramming interferes with miR-200c deficiency-induced stemness and transformation. Moreover, restoring miR-200c expression compromised EMT, stem-cell properties, and the Warburg effect caused by p53 mutations, suggesting that mutant p53 (MTp53) induces EMT-associated phenotypes and metabolic reprogramming by downregulating miR-200c. Mechanistically, decreased expression of PCK2 was observed in miR-200c- and p53-deficient mammary epithelial cells, and forced expression of miR-200c restored PCK2 in p53 mutant-expressing cells. Reduced PCK2 expression not only led to attenuated oxidative phosphorylation (OXPHOS) and increased stemness in normal mammary epithelial cells but also compromised the enhanced OXPHOS and suppression of cancer stemness exerted by miR-200c in p53 mutation-bearing basal-like breast cancer (BLBC) cells. Clinically, PCK2 expression is negatively associated with EMT markers and is downregulated in basal-like subtype and cases with low miR-200c expression or p53 mutation. Notably, low expression of PCK2 is associated with poor overall survival (OS) in patients with breast cancer. IMPLICATIONS: Together, our results suggest that p53 and miR-200c regulate OXPHOS and stem/cancer stemness through PCK2, and loss of the p53-miR-200c-PCK2 axis might provide metabolic advantages that facilitate cancer stemness, leading to the progression of BLBCs.

Metabolic Phenotypes, Dependencies, and Adaptation in Lung Cancer

Lung cancer is a heterogeneous disease that is subdivided into histopathological subtypes with distinct behaviors. Each subtype is characterized by distinct features and molecular alterations that influence tumor metabolism. Alterations in tumor metabolism can be exploited by imaging modalities that use metabolite tracers for the detection and characterization of tumors. Microenvironmental factors, including nutrient and oxygen availability and the presence of stromal cells, are a critical influence on tumor metabolism. Recent technological advances facilitate the direct evaluation of metabolic alterations in patient tumors in this complex microenvironment. In addition, molecular alterations directly influence tumor cell metabolism and metabolic dependencies that influence response to therapy. Current therapeutic approaches to target tumor metabolism are currently being developed and translated into the clinic for patient therapy.

Targeting Ferroptosis for Lung Diseases: Exploring Novel Strategies in Ferroptosis-Associated Mechanisms

Ferroptosis is an iron-dependent regulated necrosis characterized by the peroxidation damage of lipid molecular containing unsaturated fatty acid long chain on the cell membrane or organelle membrane after cellular deactivation restitution system, resulting in the cell membrane rupture. Ferroptosis is biochemically and morphologically distinct and disparate from other forms of regulated cell death. Recently, mounting studies have investigated the mechanism of ferroptosis, and numerous proteins play vital roles in regulating ferroptosis. With detailed studies, emerging evidence indicates that ferroptosis is found in multiple lung diseases, demonstrating that ferroptosis appears to be particularly important for lung diseases. The mounting interest in ferroptosis drugs specifically targeting the ferroptosis mechanism holds substantial therapeutic promise in lung diseases. The present review emphatically summarizes the functions and integrated molecular mechanisms of ferroptosis in various lung diseases, proposing that multiangle regulation of ferroptosis might be a promising strategy for the clinical treatment of lung diseases.

p53 Activation in Genetic Disorders: Different Routes to the Same Destination

The tumor suppressor p53 is critical for preventing neoplastic transformation and tumor progression. Inappropriate activation of p53, however, has been observed in a number of human inherited disorders that most often affect development of the brain, craniofacial region, limb skeleton, and hematopoietic system. Genes related to these developmental disorders are essentially involved in transcriptional regulation/chromatin remodeling, rRNA metabolism, DNA damage-repair pathways, telomere maintenance, and centrosome biogenesis. Perturbation of these activities or cellular processes may result in p53 accumulation in cell cultures, animal models, and perhaps humans as well. Mouse models of several p53 activation-associated disorders essentially recapitulate human traits, and inactivation of p53 in these models can alleviate disorder-related phenotypes. In the present review, we focus on how dysfunction of the aforementioned biological processes causes developmental defects via excessive p53 activation. Notably, several disease-related genes exert a pleiotropic effect on those cellular processes, which may modulate the magnitude of p53 activation and establish or disrupt regulatory loops. Finally, we discuss potential therapeutic strategies for genetic disorders associated with p53 misactivation.

O-GlcNAcylated p53 in the liver modulates hepatic glucose production

p53 regulates several signaling pathways to maintain the metabolic homeostasis of cells and modulates the cellular response to stress. Deficiency or excess of nutrients causes cellular metabolic stress, and we hypothesized that p53 could be linked to glucose maintenance. We show here that upon starvation hepatic p53 is stabilized by O-GlcNAcylation and plays an essential role in the physiological regulation of glucose homeostasis. More specifically, p53 binds to PCK1 promoter and regulates its transcriptional activation, thereby controlling hepatic glucose production. Mice lacking p53 in the liver show a reduced gluconeogenic response during calorie restriction. Glucagon, adrenaline and glucocorticoids augment protein levels of p53, and administration of these hormones to p53 deficient human hepatocytes and to liver-specific p53 deficient mice fails to increase glucose levels. Moreover, insulin decreases p53 levels, and over-expression of p53 impairs insulin sensitivity. Finally, protein levels of p53, as well as genes responsible of O-GlcNAcylation are elevated in the liver of type 2 diabetic patients and positively correlate with glucose and HOMA-IR. Overall these results indicate that the O-GlcNAcylation of p53 plays an unsuspected key role regulating in vivo glucose homeostasis.

Cytotoxic activity of KRAS inhibitors in combination with chemotherapeutics

INTRODUCTION

KRAS is the most frequently mutated oncogenic driver in pancreatic, lung, and colon cancer. Recently, KRAS inhibitors in clinical use show promising activity but most responses are partial and drug resistance develops. The use of therapeutics in combination with KRAS inhibitors are expected to improve outcomes.

AREAS COVERED

This review describes the KRAS G12C mutation-specific inhibitors and the SOS1-targeting inhibitors that reduce the GTP-loading of wildtype and mutated KRAS. Both types of compounds reduce tumor cell proliferation in vitro and in vivo. The combinations of the various KRAS inhibitors with downstream signaling effectors, modulators of KRAS-associated metabolic alterations and chemotherapeutics are summarized.

EXPERT OPINION

The clinical potency of mutated KRAS-specific inhibitors needs to be improved by suitable drug combinations. Inhibition of downstream signaling cascades increases toxicity and other combinations exploited comprise G12C-directed inhibitors with SOS1 inhibitors, glucose/glutamine metabolic modulators, classical chemotherapeutics, and others. The most suitable inhibitor combinations corroborated in preclinical development await clinical verification.

Phase 1, pharmacogenomic, dose-expansion study of pegargiminase plus pemetrexed and cisplatin in patients with ASS1-deficient non-squamous non-small cell lung cancer

Introduction

We evaluated the arginine‐depleting enzyme pegargiminase (ADI‐PEG20; ADI) with pemetrexed (Pem) and cisplatin (Cis) (ADIPemCis) in ASS1‐deficient non‐squamous non‐small cell lung cancer (NSCLC) via a phase 1 dose‐expansion trial with exploratory biomarker analysis.

Methods

Sixty‐seven chemonaïve patients with advanced non‐squamous NSCLC were screened, enrolling 21 ASS1‐deficient subjects from March 2015 to July 2017 onto weekly pegargiminase (36 mg/m²) with Pem (500 mg/m²) and Cis (75 mg/m²), every 3 weeks (four cycles maximum), with maintenance Pem or pegargiminase. Safety, pharmacodynamics, immunogenicity, and efficacy were determined; molecular biomarkers were annotated by next‐generation sequencing and PD‐L1 immunohistochemistry.

Results

ADIPemCis was well‐tolerated. Plasma arginine and citrulline were differentially modulated; pegargiminase antibodies plateaued by week 10. The disease control rate was 85.7% (n = 18/21; 95% CI 63.7%–97%), with a partial response rate of 47.6% (n = 10/21; 95% CI 25.7%–70.2%). The median progression‐free and overall survivals were 4.2 (95% CI 2.9–4.8) and 7.2 (95% CI 5.1–18.4) months, respectively. Two PD‐L1‐expressing (≥1%) patients are alive following subsequent pembrolizumab immunotherapy (9.5%). Tumoral ASS1 deficiency enriched for p53 (64.7%) mutations, and numerically worse median overall survival as compared to ASS1‐proficient disease (10.2 months; n = 29). There was no apparent increase in KRAS mutations (35.3%) and PD‐L1 (<1%) expression (55.6%). Re‐expression of tumoral ASS1 was detected in one patient at progression (n = 1/3).

Conclusions

ADIPemCis was safe and highly active in patients with ASS1‐deficient non‐squamous NSCLC, however, survival was poor overall. ASS1 loss was co‐associated with p53 mutations. Therapies incorporating pegargiminase merit further evaluation in ASS1‐deficient and treatment‐refractory NSCLC.

Metabostemness in cancer: Linking metaboloepigenetics and mitophagy in remodeling cancer stem cells

Cancer stem cells (CSCs) are rare populations of malignant cells with stem cell-like features of self-renewal, uninterrupted differentiation, tumorigenicity, and resistance to conventional therapeutic agents, and these cells have a decisive role in treatment failure and tumor relapse. The self-renewal potential of CSCs with atypical activation of developmental signaling pathways involves the maintenance of stemness to support cancer progression. The acquisition of stemness in CSCs has been accomplished through genetic and epigenetic rewiring following the metabolic switch. In this context, "metabostemness" denotes the metabolic parameters that essentially govern the epitranscriptional gene reprogramming mechanism to dedifferentiate tumor cells into CSCs. Several metabolites often referred to as oncometabolites can directly remodel chromatin structure and thereby influence the operation of epitranscriptional circuits. This integrated metaboloepigenetic dimension of CSCs favors the differentiated cells to move in dedifferentiated macrostates. Some metabolic events might perform as early drivers of epitranscriptional reprogramming; however, subsequent metabolic hits may govern the retention of stemness properties in the tumor mass. Interestingly, selective removal of mitochondria through autophagy can promote metabolic plasticity and alter metabolic states during differentiation and dedifferentiation. In this connection, novel metabostemness-specific drugs can be generated as potential cancer therapeutics to target the metaboloepigenetic circuitry to eliminate CSCs.

Metabolic networks in mutant KRAS-driven tumours: tissue specificities and the microenvironment

Oncogenic mutations in KRAS drive common metabolic programmes that facilitate tumour survival, growth and immune evasion in colorectal carcinoma, non-small-cell lung cancer and pancreatic ductal adenocarcinoma. However, the impacts of mutant KRAS signalling on malignant cell programmes and tumour properties are also dictated by tumour suppressor losses and physiological features specific to the cell and tissue of origin. Here we review convergent and disparate metabolic networks regulated by oncogenic mutant KRAS in colon, lung and pancreas tumours, with an emphasis on co-occurring mutations and the role of the tumour microenvironment. Furthermore, we explore how these networks can be exploited for therapeutic gain.

Metabolic Reprogramming: A Friend or Foe to Cancer Therapy?

Drug resistance is a major cause of cancer treatment failure, effectively driven by processes that promote escape from therapy-induced cell death. The mechanisms driving evasion of apoptosis have been widely studied across multiple cancer types, and have facilitated new and exciting therapeutic discoveries with the potential to improve cancer patient care. However, an increasing understanding of the crosstalk between cancer hallmarks has highlighted the complexity of the mechanisms of drug resistance, co-opting pathways outside of the canonical "cell death" machinery to facilitate cell survival in the face of cytotoxic stress. Rewiring of cellular metabolism is vital to drive and support increased proliferative demands in cancer cells, and recent discoveries in the field of cancer metabolism have uncovered a novel role for these programs in facilitating drug resistance. As a key organelle in both metabolic and apoptotic homeostasis, the mitochondria are at the forefront of these mechanisms of resistance, coordinating crosstalk in the event of cellular stress, and promoting cellular survival. Importantly, the appreciation of this role metabolism plays in the cytotoxic response to therapy, and the ability to profile metabolic adaptions in response to treatment, has encouraged new avenues of investigation into the potential of exploiting metabolic addictions to improve therapeutic efficacy and overcome drug resistance in cancer. Here, we review the role cancer metabolism can play in mediating drug resistance, and the exciting opportunities presented by imposed metabolic vulnerabilities.

Childhood trauma, the stress response and metabolic syndrome: A focus on DNA methylation

Childhood trauma (CT) is well established as a potent risk factor for the development of mental disorders. However, the potential of adverse early experiences to exert chronic and profound effects on physical health, including aberrant metabolic phenotypes, has only been more recently explored. Among these consequences is metabolic syndrome (MetS), which is characterised by at least three of five related cardiometabolic traits: hypertension, insulin resistance/hyperglycaemia, raised triglycerides, low high-density lipoprotein and central obesity. The deleterious effects of CT on health outcomes may be partially attributable to dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, which coordinates the response to stress, and the consequent fostering of a pro-inflammatory environment. Epigenetic tags, such as DNA methylation, which are sensitive to environmental influences provide a means whereby the effects of CT can be biologically embedded and persist into adulthood to affect health and well-being. The methylome regulates the transcription of genes involved in the stress response, metabolism and inflammation. This narrative review examines the evidence for DNA methylation in CT and MetS in order to identify shared neuroendocrine and immune correlates that may mediate the increased risk of MetS following CT exposure. Our review specifically highlights differential methylation of FKBP5, the gene that encodes FK506-binding protein 51 and has pleiotropic effects on stress responding, inflammation and energy metabolism, as a central candidate to understand the molecular aetiology underlying CT-associated MetS risk.

Molecular and cellular pathways contributing to brain aging

Aging is the leading risk factor for several age-associated diseases such as neurodegenerative diseases. Understanding the biology of aging mechanisms is essential to the pursuit of brain health. In this regard, brain aging is defined by a gradual decrease in neurophysiological functions, impaired adaptive neuroplasticity, dysregulation of neuronal Ca2+ homeostasis, neuroinflammation, and oxidatively modified molecules and organelles. Numerous pathways lead to brain aging, including increased oxidative stress, inflammation, disturbances in energy metabolism such as deregulated autophagy, mitochondrial dysfunction, and IGF-1, mTOR, ROS, AMPK, SIRTs, and p53 as central modulators of the metabolic control, connecting aging to the pathways, which lead to neurodegenerative disorders. Also, calorie restriction (CR), physical exercise, and mental activities can extend lifespan and increase nervous system resistance to age-associated neurodegenerative diseases. The neuroprotective effect of CR involves increased protection against ROS generation, maintenance of cellular Ca2+ homeostasis, and inhibition of apoptosis. The recent evidence about the modem molecular and cellular methods in neurobiology to brain aging is exhibiting a significant potential in brain cells for adaptation to aging and resistance to neurodegenerative disorders.

Proline oxidase silencing inhibits p53-dependent apoptosis in MCF-7 breast cancer cells

Proline oxidase (POX) is mitochondrial proline-degrading enzyme of dual apoptosis/survival function. POX expression and proline availability are considered an underlying mechanism for differential POX functions. The mechanism for POX-dependent regulation of cell death/survival was studied in wild-type (MCF-7^WT) and shRNA POX-silenced breast cancer cells (MCF-7^iPOX). Proline concentration and proteomic analyses were determined by LC/MS/QTOF and LC/MS/ORBITRA, respectively. Inhibition of collagen biosynthesis (proline utilizing process) by 2-methoxyestradiol (2ME) contributed to induction of apoptosis in MCF-7^WT cells, as detected by increase in the expression of active caspase-3, -9 and p53. The process was not shown in MCF-7^iPOX. In MCF-7^iPOX cells prolidase activity and expression as well as proline concentration were drastically increased, compared to MCF-7^WT cells. Down-regulation of p53 in MCF-7^iPOX cells was corroborated by proteomic analysis showing decrease in the expression of p53-related proteins. The mechanism for down-regulation of p53 expression in MCF-7^iPOX cells was found at the level of p53-PEPD complex formation that was counteracted by hydrogen peroxide treatment. In this study, we found that silencing POX modulate pro-survival phenotype of MCF-7 cells and suggest that the mechanism of this process undergoes through down-regulation of p53-dependent signaling.

Lactate Modulates Cellular Metabolism Through Histone Lactylation-Mediated Gene Expression in Non-Small Cell Lung Cancer

Lactate has been observed to fuel TCA cycle and is associated with cancer progression in human lung cancer, the leading cause of cancer deaths worldwide, but the effect of lactate on lung cancer metabolism is rarely reported. In this study, disordered metabolism in non-small cell lung cancer was demonstrated by increased G6PD and SDHA protein levels via immunofluorescence, and up-regulated lactate dehydrogenase was found to be associated with poor prognosis. Then flow cytometry and Seahorse XFe analyzer were utilized to detect the effect of lactate on glycolysis and mitochondrial function in non-small cell lung cancer cells. The results show that in non-small cell lung cancer cells lactate attenuates glucose uptake and glycolysis while maintaining mitochondrial homeostasis as indicated by improved mitochondrial membrane potential. Further exploration found that mRNA levels of glycolytic enzymes (HK-1, PKM) and TCA cycle enzymes (SDHA, IDH3G) are respectively down-regulated and up-regulated by lactate, and increased histone lactylation was observed in promoters of HK-1 and IDH3G via chromatin immunoprecipitation assay. Taken together, the above results indicate that lactate modulates cellular metabolism at least in part through histone lactylation-mediated gene expression in non-small cell lung cancer.

Drug repurposing for hyperlipidemia associated disorders: An integrative network biology and machine learning approach

Hyperlipidemia causes diseases like cardiovascular disease, cancer, Type II Diabetes and Alzheimer's disease. Drugs that specifically target HL associated diseases are required for treatment. 34 KEGG pathways targeted by lipid lowering drugs were used to construct a directed protein-protein interaction network and driver nodes were determined using CytoCtrlAnalyser plugin of Cytoscape 3.6. The involvement of driver nodes of HL in other diseases was verified using GWAS. The central nodes of the network and 34 overrepresented pathways had a critical role in Hyperlipidemia. The PI3K-AKT signalling pathway, non-essentiality, non-centrality and approved drug target status were the predominant features of the driver nodes. Next, a Random Forest classifier was trained on 1445 molecular descriptors calculated using PaDEL for 50 approved lipid lowering and 84 lipid raising drugs as the positive and negative training set respectively. The classifier showed average accuracy of 76.8 % during 5-fold cross validation with AUC of 0.79 ± 0.06 for the ROC curve. The classifier was applied to select molecules with favourable properties for lipid lowering from the 130 approved drugs interacting with the identified driver nodes. We have integrated diverse network data and machine learning to predict repurposing of nine drugs for treatment of HL associated diseases.

The Relationship Between Menopause and Metabolic Syndrome: Experimental and Bioinformatics Analysis

Menopausal hormonal changes have been associated with the emergence of the metabolic syndrome (MetS) and its consequences such as type 2 diabetes (T2D) and cardiovascular diseases (CVD). The common gene signature and the associated signaling pathways of MetS, T2D, CVD and menopause status have not been widely studied. We analyzed a total of 314 women aged between 35 and 75 years. The sample was divided into two groups: Group I, including women in the premenopausal period and Group II, comprising women in the post-menopausal period. The presence of MetS and its components were evaluated, as well as occurrence of T2D and CVD in both groups. We also exploited the translational bioinformatics approach to choose the common gene signatures for MetS, T2D, CVD and the menopause status. The frequency of the MetS was significantly higher in postmenopausal women than in premenopausal ones (67.1 vs. 27.2%, p < 0.001). Gene mining analysis revealed that a total of 47 genes were commonly associated with MetS, T2D, CVD and the menopausal changes. The gene enrichment analysis showed that these genes were markedly enriched in biological processes, including positive regulation of binding, positive regulation of leukocyte cell-cell adhesion, regulation of lipid localization. Furthermore, P53 signaling pathway, prolactin signaling pathway, parathyroid hormone synthesis, secretion and action were the top enriched pathways. Additionally, network analysis revealed TGFB1, SPP1, MMP2, MMP9, CCL2, IGF1, EGFR, ICAM1, TNF and IL6 as important hub genes with significant interacting partners. These hub genes identified in our study may play key role in menopausal changes and influence the risks of MetS, T2D and CVD.

Dual PPARγ/ɑ agonist oroxyloside suppresses cell cycle progression by glycolipid metabolism switch-mediated increase of reactive oxygen species levels

Cancer cells prefers to rely on aerobic glycolysis than pyruvate oxidation to meet the high demand of energy for rapidly proliferation. Peroxisome proliferator-activated receptors (PPARs) are a kind of important ligand-inducible transcription factors and play crucial roles in glucose and lipid metabolism. Careful designing of novel agonists for PPARs, may show improvement with the side effects and also increase the therapeutic value for cancer and other metabolic disorder diseases. Compared with normal human liver cells, lower expression or acitivity of PPARs is observed in hepatocellular carcinoma (HCC). In this study, we show that oroxyloside (OAG) is a new dual agonist of PPARγ/ɑ, and inhibits cell proliferation of HCC based on metabolic switch. Via both PPAR-dependent and PPAR-independent regulations on glycolipid metabolic enzymes, OAG shuts down the catabolism of glucose and promotes fatty acids oxidation to generate acetyl-CoA for TCA cycle and oxidative phosphorylation. The metabolic switch induced by OAG results in a marked increase of reactive oxygen species (ROS) levels, leading to rapid dephosphorylation of RB and cell-cycle arrest in G1 phase. Pyruvate dehydrogenase kinase 4 (PDK4) and β-Oxidation are required for the suppression of cell cycle progression by OAG. Together, our findings provide a new drug candidate and a viable therapeutic strategy for HCC based on metabolic reprogram.

Associations of TP53 codon 72 polymorphism with complications and comorbidities in patients with type 1 diabetes

Wild-type TP53 plays an important role in the regulation of immune response and systemic inflammation. In type 1 diabetes (T1D), TP53 pathways are upregulated and an increased susceptibility to apoptosis is observed. We hypothesize that TP53 codon 72 polymorphism could be associated with complications and comorbidities in patients with T1D. We have investigated the associations of the TP53 codon 72 polymorphism with the T1D complications and comorbidities (retinopathy, nephropathy, hypertension, dyslipidemia, autoimmune thyroiditis, and celiac disease) in 350 patients. The key results of our approach are as follows: (1) In diabetic subjects, the Pro/Pro genotype is associated with an increased risk of microvascular complications, dyslipidemia, and celiac disease; (2) the Arg/Arg variant is associated with a decreased risk of autoimmune thyroiditis and celiac disease; (3) the Pro allele is associated with an increased risk of dyslipidemia, autoimmune thyroiditis, and celiac disease. Although further studies are required, our results for the first time indicate that the TP53 codon 72 polymorphism could be considered a genetic marker to predict the increased susceptibility to some T1D complications and comorbidities. KEY MESSAGES: We analyzed the TP53 codon 72 polymorphism in patients with T1D. Pro/Pro genotype is associated with an increased risk of microvascular complications, dyslipidemia, and celiac disease. The Arg/Arg variant is associated with a decreased risk of autoimmune thyroiditis and celiac disease. The Pro allele is associated with an increased risk of dyslipidemia, autoimmune thyroiditis, and celiac disease.

Racially Disparate Expression of mTOR/ERK-1/2 Allied Proteins in Cancer

Recent studies revealed that ethnic differences in mechanistic target of rapamycin (mTOR) and extracellular signal-regulated kinase (ERK-1/2) signaling pathways might be associated with the development and progression of different human malignancies. The African American (AA) population has an increased rate of cancer incidence and mortality compared to the Caucasian American (CA) population. Although the socioeconomic differences across different ethnic groups contribute to the disparity in developing different cancers, recent scientific evidence indicates the association of molecular and genetic variations in racial disparities of different human malignancies. The mTOR and ERK-1/2 signaling pathways are one of the well-known oncogenic signaling mechanisms that regulate diverse molecular and phenotypic aspects of normal as well as cancer cells in response to different external or internal stimuli. To date, very few studies have been carried out to explore the significance of racial disparity with abnormal mTOR and ERK-1/2 kinase signaling pathways, which may contribute to the development of aggressive human cancers. In this review, we discuss the differential regulation of mTOR and ERK-1/2 kinase signaling pathways across different ethnic groups, especially between AA and CA populations. Notably, we observed that key signaling proteins associated with mTOR and ERK-1/2 pathway including transforming growth factor-beta (TGF-β), Akt, and VEGFR showed racially disparate expression in cancer patients. Overall, this review article encompasses the significance of racially disparate signaling molecules related to mTOR/ERK1/2 and their potential in developing tailor-made anti-cancer therapies.

Metformin Inhibits the Urea Cycle and Reduces Putrescine Generation in Colorectal Cancer Cell Lines

The urea cycle (UC) removes the excess nitrogen and ammonia generated by nitrogen-containing compound composites or protein breakdown in the human body. Research has shown that changes in UC enzymes are not only related to tumorigenesis and tumor development but also associated with poor survival in hepatocellular, breast, and colorectal cancers (CRC), etc. Cytoplasmic ornithine, the intermediate product of the urea cycle, is a specific substrate for ornithine decarboxylase (ODC, also known as ODC1) for the production of putrescine and is required for tumor growth. Polyamines (spermidine, spermine, and their precursor putrescine) play central roles in more than half of the steps of colorectal tumorigenesis. Given the close connection between polyamines and cancer, the regulation of polyamine metabolic pathways has attracted attention regarding the mechanisms of action of chemical drugs used to prevent CRC, as the drug most widely used for treating type 2 diabetes (T2D), metformin (Met) exhibits antitumor activity against a variety of cancer cells, with a vaguely defined mechanism. In addition, the influence of metformin on the UC and putrescine generation in colorectal cancer has remained unclear. In our study, we investigated the effect of metformin on the UC and putrescine generation of CRC in vivo and in vitro and elucidated the underlying mechanisms. In nude mice bearing HCT116 tumor xenografts, the administration of metformin inhibited tumor growth without affecting body weight. In addition, metformin treatment increased the expression of monophosphate (AMP)-activated protein kinase (AMPK) and p53 in both HCT116 xenografts and colorectal cancer cell lines and decreased the expression of the urea cycle enzymes, including carbamoyl phosphate synthase 1 (CPS1), arginase 1 (ARG1), ornithine trans-carbamylase (OTC), and ODC. The putrescine levels in both HCT116 xenografts and HCT116 cells decreased after metformin treatment. These results demonstrate that metformin inhibited CRC cell proliferation via activating AMPK/p53 and that there was an association between metformin, urea cycle inhibition and a reduction in putrescine generation.

Increased insulin sensitivity and diminished pancreatic beta-cell function in DNA repair deficient Ercc1d/- mice

BACKGROUND

Type 2 diabetes (T2DM) is an age-associated disease characterized by hyperglycemia due to insulin resistance and decreased beta-cell function. DNA damage accumulation has been associated with T2DM, but whether DNA damage plays a role in the pathogenesis of the disease is unclear. Here, we used mice deficient for the DNA excision-repair gene Ercc1 to study the impact of persistent endogenous DNA damage accumulation on energy metabolism, glucose homeostasis and beta-cell function.

METHODS

ERCC1-XPF is an endonuclease required for multiple DNA repair pathways and reduced expression of ERCC1-XPF causes accelerated accumulation of unrepaired endogenous DNA damage and accelerated aging in humans and mice. In this study, energy metabolism, glucose metabolism, beta-cell function and insulin sensitivity were studied in Ercc1^d/- mice, which model a human progeroid syndrome.

RESULTS

Ercc1^d/- mice displayed suppression of the somatotropic axis and altered energy metabolism. Insulin sensitivity was increased, whereas, plasma insulin levels were decreased in Ercc1^d/- mice. Fasting induced hypoglycemia in Ercc1^d/- mice, which was the result of increased glucose disposal. Ercc1^d/- mice exhibit a significantly reduced beta-cell area, even compared to control mice of similar weight. Glucose-stimulated insulin secretion in vivo was decreased in Ercc1^d/- mice. Islets isolated from Ercc1^d/- mice showed increased DNA damage markers, decreased glucose-stimulated insulin secretion and increased susceptibility to apoptosis.

CONCLUSION

Spontaneous DNA damage accumulation triggers an adaptive response resulting in improved insulin sensitivity. Loss of DNA repair, however, does negatively impacts beta-cell survival and function in Ercc1^d/- mice.

Mitochondria: The metabolic switch of cellular oncogenic transformation

Mitochondria, well recognized as the "powerhouse" of cells, are maternally inherited organelles with bacterial ancestry that play essential roles in a myriad of cellular functions. It has become profoundly evident that mitochondria regulate a wide array of cellular and metabolic functions, including biosynthetic metabolism, cell signaling, redox homeostasis, and cell survival. Correspondingly, defects in normal mitochondrial functioning have been implicated in various human malignancies. Cancer development involves the activation of oncogenes, inactivation of tumor suppressor genes, and impairment of apoptotic programs in cells. Mitochondria have been recognized as the site of key metabolic switches for normal cells to acquire a malignant phenotype. This review outlines the role of mitochondria in human malignancies and highlights potential aspects of mitochondrial metabolism that could be targeted for therapeutic development.

A Mouse Homolog of a Human TP53 Germline Mutation Reveals a Lipolytic Activity of p53

The physiological effects of the many germline mutations of TP53, encoding the tumor suppressor protein p53, are poorly understood. Here we report generating a p53 R178C knockin mouse modeling the human TP53 R181C mutation, which is notable for its prevalence and prior molecular characterization. Consistent with its weak cancer penetrance in humans, homozygous p53^178C/C mice show a modest increase in tumorigenesis but, surprisingly, are lean with decreased body fat content. They display evidence of increased lipolysis and upregulation of fatty acid metabolism in their inguinal white adipose tissue (iWAT). Gene expression and chromatin immunoprecipitation sequencing (ChIP-seq) analyses show that the mutant p53 bound and trans-activated Beta-3-Adrenergic Receptor (ADRB3), a gene that is known to promote lipolysis and is associated with obesity. This study reveals that a germline mutation of p53 can affect fat metabolism, which has been implicated in cancer development.

Knockin of the mouse homolog of a human TP53 germline mutation known to cause Li-Fraumeni syndrome, a cancer predisposition disorder, results in a mouse model characterized by lower body fat content. Kang et al. show that enhancing transactivation of the lipolytic gene ADRB3 by mutant p53 contributes to this phenotype.

Metabolic regulation of cell competition

Cell Competition is a selective process by which viable cells are eliminated from developing or adult tissues by interactions with their neighbors. In many cases, the eliminated cells (losers) display reduced fitness, yet they would be able to sustain tissue growth or maintenance in a homotypic environment, and are only eliminated when confronted with surrounding wild type cells (winners). In addition, cells with oncogenic mutations that do not show reduced fitness can also be eliminated from tissues when surrounded by wild type cells. Depending on the context, transformed cells can also become supercompetitors and eliminate surrounding wild type cells, thereby promoting tumor formation. Several factors have been shown to play essential roles in Cell Competition, including genes relevant in developmental growth, tumor formation and epithelial apico-basal polarity. Recent discoveries, however, suggest that energy metabolism plays a central role in very different models of cell competition. Here we review the involvement of mitochondrial dynamics and metabolism, autophagy and nutritional status in cell competition and discuss the possible implications of this emerging field.

Mitochondria and nucleus cross-talk: Signaling in metabolism, apoptosis, and differentiation, and function in cancer

The cross-talk between the mitochondrion and the nucleus regulates cellular functions, including differentiation and adaptation to stress. Mitochondria supply metabolites for epigenetic modifications and other nuclear-associated activities and certain mitochondrial proteins were found in the nucleus. The voltage-dependent anion channel 1 (VDAC1), localized at the outer mitochondrial membrane (OMM) is a central protein in controlling energy production, cell growth, Ca2+ homeostasis, and apoptosis. To alter the cross-talk between the mitochondria and the nucleus, we used specific siRNA to silence the expression of VDAC1 in glioblastoma (GBM) U87-MG and U118-MG cell-derived tumors, and then monitored the nuclear localization of mitochondrial proteins and the methylation and acetylation of histones. Depletion of VDAC1 from tumor cells reduced metabolism, leading to inhibition of tumor growth, and several tumor-associated processes and signaling pathways linked to cancer development. In addition, we demonstrate that certain mitochondrial pro-apoptotic proteins such as caspases 3, 8, and 9, and p53 were unexpectedly overexpressed in tumors, suggesting that they possess additional non-apoptotic functions. VDAC1 depletion and metabolic reprograming altered their expression levels and subcellular localization, specifically their translocation to the nucleus. In addition, VDAC1 depletion also leads to epigenetic modifications of histone acetylation and methylation, suggesting that the interchange between metabolism and cancer signaling pathways involves mitochondria-nucleus cross-talk. The mechanisms regulating mitochondrial protein trafficking into and out of the nucleus and the role these proteins play in the nucleus remain to be elucidated.

The Interplay Between Tumor Suppressor p53 and Hypoxia Signaling Pathways in Cancer

Hypoxia is a hallmark of solid tumors and plays a critical role in different steps of tumor progression, including proliferation, survival, angiogenesis, metastasis, metabolic reprogramming, and stemness of cancer cells. Activation of the hypoxia-inducible factor (HIF) signaling plays a critical role in regulating hypoxic responses in tumors. As a key tumor suppressor and transcription factor, p53 responds to a wide variety of stress signals, including hypoxia, and selectively transcribes its target genes to regulate various cellular responses to exert its function in tumor suppression. Studies have demonstrated a close but complex interplay between hypoxia and p53 signaling pathways. The p53 levels and activities can be regulated by the hypoxia and HIF signaling differently depending on the cell/tissue type and the severity and duration of hypoxia. On the other hand, p53 regulates the hypoxia and HIF signaling at multiple levels. Many tumor-associated mutant p53 proteins display gain-of-function (GOF) oncogenic activities to promote cancer progression. Emerging evidence has also shown that GOF mutant p53 can promote cancer progression through its interplay with the hypoxia and HIF signaling pathway. In this review, we summarize our current understanding of the interplay between the hypoxia and p53 signaling pathways, its impact upon cancer progression, and its potential application in cancer therapy.

Flubendazole, FDA-approved anthelmintic, elicits valid antitumor effects by targeting P53 and promoting ferroptosis in castration-resistant prostate cancer

On account of incurable castration-resistant prostate cancer (CRPC) inevitably developing after treating with androgen deprivation therapy, it is an urgent need to find new therapeutic strategies. Flubendazole is a well-known anti-malarial drug that is recently reported to be a potential anti-tumor agent in various types of human cancer cells. However, whether flubendazole could inhibit the castration-resistant prostate cancer has not been well charified. Thus, the aim of the present study was to characterize the precise mechanism of action of flubendazole on the CRPC. In this study, we investigated the potential effect of flubendazole on cell proliferation, cell cycle and cell death in CRPC cells (PC3 and DU145). We found that flubendazole inhibited cell proliferation, caused cell cycle arrest in G2/M phase and promoted cell death in vitro, and suppressed growth of CRPC tumor in xenograft models. In addition, we reported that flubendazole induced the expression of P53, which partly accounted for the G2/M phase arrest and led to inhibition of the transcription of SLC7A11, and then downregulated the GPX4, which is a major ferroptosis-related gene. Furthermore, flubendazole exhibited synergistic effect with 5-fluorouracil (5-Fu) in chemotherapy of CRPC. This study provides biological evidence that flubendazole is a novel P53 inducer which exerts anti-proliferation and pro-apoptosis effects in CRPC through hindering the cell cycle and activating the ferroptosis, and indicates that a novel utilization of flubendazole in neoadjuvant chemotherapy of CRPC.

CDK4/6 Inhibition Reprograms Mitochondrial Metabolism in BRAFV600 Melanoma via a p53 Dependent Pathway

Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors are being tested in numerous clinical trials and are currently employed successfully in the clinic for the treatment of breast cancers. Understanding their mechanism of action and interaction with other therapies is vital in their clinical development. CDK4/6 regulate the cell cycle via phosphorylation and inhibition of the tumour suppressor RB, and in addition can phosphorylate many cellular proteins and modulate numerous cellular functions including cell metabolism. Metabolic reprogramming is observed in melanoma following standard-of-care BRAF/MEK inhibition and is involved in both therapeutic response and resistance. In preclinical models, CDK4/6 inhibitors overcome BRAF/MEK inhibitor resistance, leading to sustained tumour regression; however, the metabolic response to this combination has not been explored. Here, we investigate how CDK4/6 inhibition reprograms metabolism and if this alters metabolic reprogramming observed upon BRAF/MEK inhibition. Although CDK4/6 inhibition has no substantial effect on the metabolic phenotype following BRAF/MEK targeted therapy in melanoma, CDK4/6 inhibition alone significantly enhances mitochondrial metabolism. The increase in mitochondrial metabolism in melanoma cells following CDK4/6 inhibition is fuelled in part by both glutamine metabolism and fatty acid oxidation pathways and is partially dependent on p53. Collectively, our findings identify new p53-dependent metabolic vulnerabilities that may be targeted to improve response to CDK4/6 inhibitors.

Regulation of p53 stability as a therapeutic strategy for cancer

The tumor suppressor protein p53 participates in the control of key biological functions such as cell death, metabolic homeostasis and immune function, which are closely related to various diseases such as tumors, metabolic disorders, infection and neurodegeneration. The p53 gene is also mutated in approximately 50% of human cancer cells. Mutant p53 proteins escape from the ubiquitination-dependent degradation, gain oncogenic function and promote the carcinogenesis, malignant progression, metastasis and chemoresistance. Therefore, the stability of both wild type and mutant p53 needs to be precisely regulated to maintain normal functions and targeting the p53 stability is one of the therapeutic strategies against cancer. Here, we focus on compound-induced degradation of p53 by both the ubiquitination-dependent proteasome and autophagy-lysosome degradation pathways. We also review other posttranslational modifications which control the stability of p53 and the biological functions involved in these processes. This review provides the current theoretical basis for the regulation of p53 abundance and its possible applications in different diseases.

An AMPK-dependent, non-canonical p53 pathway plays a key role in adipocyte metabolic reprogramming

It has been known adipocytes increase p53 expression and activity in obesity, however, only canonical p53 functions (i.e. senescence and apoptosis) are attributed to inflammation-associated metabolic phenotypes. Whether or not p53 is directly involved in mature adipocyte metabolic regulation remains unclear. Here we show p53 protein expression can be up-regulated in adipocytes by nutrient starvation without activating cell senescence, apoptosis, or a death-related p53 canonical pathway. Inducing the loss of p53 in mature adipocytes significantly reprograms energy metabolism and this effect is primarily mediated through a AMP-activated protein kinase (AMPK) pathway and a novel downstream transcriptional target, lysosomal acid lipase (LAL). The pathophysiological relevance is further demonstrated in a conditional and adipocyte-specific p53 knockout mouse model. Overall, these data support a non-canonical p53 function in the regulation of adipocyte energy homeostasis and indicate that the dysregulation of this pathway may be involved in developing metabolic dysfunction in obesity.

Comparative metabolic profiles of total and partial body radiation exposure in mice using an untargeted metabolomics approach

INTRODUCTION

A large scale population exposure to ionizing radiation during intentional or unintentional nuclear accidents undoubtedly generates a complex scenario with partial-body as well as total-body irradiated victims. A high throughput technique based rapid assessment method is an urgent necessity for stratification of exposed subjects independent of whether exposure is uniform total-body or non-homogenous partial-body.

OBJECTIVE

Here, we used Nuclear Magnetic Resonance (NMR) based metabolomics approach to compare and identify candidate metabolites differentially expressed in total and partially irradiated mice model.

METHODS

C57BL/6 male mice (8-10 weeks) were irradiated total-body or locally to thoracic, hind limb or abdominal regions with 10 Gy of gamma radiation. Urine samples collected at 24 h post irradiation were examined using high resolution NMR spectroscopy and the datasets were analysed using multivariate analysis.

RESULTS

Multivariate and metabolic pathway analysis in urine samples collected at 24 h post-radiation exhibited segregation of all irradiated groups from controls. Metabolites associated with energy metabolism, gut flora metabolism and taurine were common to partial and total-body irradiation, thus making them potential candidates for radiation exposure. Nevertheless, a distinct metabolic pattern was observed in partial-body exposed groups with maximum changes observed in the hind limb region indicating differential tissue associated radiation sensitivity. The organ-specific changes may provide an early warning regarding the physiological system at risk after radiation injury.

CONCLUSION

The study affirms potentiality of metabolite markers and comparative analysis could be an important piece of information for an integrated solution to a complex research question in terms of radiation biomarkers.

TERT-Regulation and Roles in Cancer Formation

Telomerase reverse transcriptase (TERT) is a catalytic subunit of telomerase. Telomerase complex plays a key role in cancer formation by telomere dependent or independent mechanisms. Telomere maintenance mechanisms include complex TERT changes such as gene amplifications, TERT structural variants, TERT promoter germline and somatic mutations, TERT epigenetic changes, and alternative lengthening of telomere. All of them are cancer specific at tissue histotype and at single cell level. TERT expression is regulated in tumors via multiple genetic and epigenetic alterations which affect telomerase activity. Telomerase activity via TERT expression has an impact on telomere length and can be a useful marker in diagnosis and prognosis of various cancers and a new therapy approach. In this review we want to highlight the main roles of TERT in different mechanisms of cancer development and regulation.

Exploring the multiple roles of guardian of the genome: P53

Background

Cells have evolved balanced mechanisms to protect themselves by initiating a specific response to a variety of stress. TheTP53gene, encoding P53 protein, is one of the many widely studied genes in human cells owing to its multifaceted functions and complex dynamics. The tumour-suppressing activity of P53 plays a principal role in the cellular response to stress. The majority of the human cancer cells exhibit the inactivation of the P53 pathway. In this review, we discuss the recent advancements in P53 research with particular focus on the role of P53 in DNA damage responses, apoptosis, autophagy, and cellular metabolism. We also discussed important P53-reactivation strategies that can play a crucial role in cancer therapy and the role of P53 in various diseases.

Main body

We used electronic databases like PubMed and Google Scholar for literature search. In response to a variety of cellular stress such as genotoxic stress, ischemic stress, oncogenic expression, P53 acts as a sensor, and suppresses tumour development by promoting cell death or permanent inhibition of cell proliferation. It controls several genes that play a role in the arrest of the cell cycle, cellular senescence, DNA repair system, and apoptosis. P53 plays a crucial role in supporting DNA repair by arresting the cell cycle to purchase time for the repair system to restore genome stability. Apoptosis is essential for maintaining tissue homeostasis and tumour suppression. P53 can induce apoptosis in a genetically unstable cell by interacting with many pro-apoptotic and anti-apoptotic factors.

Furthermore, P53 can activate autophagy, which also plays a role in tumour suppression. P53 also regulates many metabolic pathways of glucose, lipid, and amino acid metabolism. Thus under mild metabolic stress, P53 contributes to the cell’s ability to adapt to and survive the stress.

Conclusion

These multiple levels of regulation enable P53 to perform diversified roles in many cell responses. Understanding the complete function of P53 is still a work in progress because of the inherent complexity involved in between P53 and its target proteins. Further research is required to unravel the mystery of this Guardian of the genome “TP53”.

Increased mTOR activity and metabolic efficiency in mouse and human cells containing the African-centric tumor-predisposing p53 variant Pro47Ser

The Pro47Ser variant of p53 (S47) exists in African-descent populations and is associated with increased cancer risk in humans and mice. Due to impaired repression of the cystine importer Slc7a11, S47 cells show increased glutathione (GSH) accumulation compared to cells with wild -type p53. We show that mice containing the S47 variant display increased mTOR activity and oxidative metabolism, as well as larger size, improved metabolic efficiency, and signs of superior fitness. Mechanistically, we show that mTOR and its positive regulator Rheb display increased association in S47 cells; this is due to an altered redox state of GAPDH in S47 cells that inhibits its ability to bind and sequester Rheb. Compounds that decrease glutathione normalize GAPDH-Rheb complexes and mTOR activity in S47 cells. This study reveals a novel layer of regulation of mTOR by p53, and raises the possibility that this variant may have been selected for in early Africa.

Approaches to Investigating the Protein Interactome of PTEN

The tumor suppressor phosphatase and tensin homologue (PTEN) is a redox-sensitive dual specificity phosphatase with an essential role in the negative regulation of the PI3K-AKT signaling pathway, affecting metabolic and cell survival processes. PTEN is commonly mutated in cancer, and dysregulation in the metabolism of PIP₃ is implicated in other diseases such as diabetes. PTEN interactors are responsible for some functional roles of PTEN beyond the negative regulation of the PI3K pathway and are thus of great importance in cell biology. Both high-data content proteomics-based approaches and low-data content PPI approaches have been used to investigate the interactome of PTEN and elucidate further functions of PTEN. While low-data content approaches rely on co-immunoprecipitation and Western blotting, and as such require previously generated hypotheses, high-data content approaches such as affinity pull-down proteomic assays or the yeast 2-hybrid system are hypothesis generating. This review provides an overview of the PTEN interactome, including redox effects, and critically appraises the methods and results of high-data content investigations into the global interactome of PTEN. The biological significance of findings from recent studies is discussed and illustrates the breadth of cellular functions of PTEN that can be discovered by these approaches.

Functional interplay among thiol-based redox signaling, metabolism, and ferroptosis unveiled by a genetic variant of TP53

The p53 tumor suppressor protein is a transcription factor and master stress response mediator, and it is subject to reduction-oxidation (redox)-dependent regulation. The P47S variant of TP53, which exists primarily in African-descent populations, associates with an elevated abundance of low molecular weight (LMW) thiols, including glutathione (GSH) and coenzyme A (CoA). Here we show that S47 and P47 cells exhibit distinct metabolic profiles, controlled by their different redox states and expression of Activating Transcription Factor-4 (ATF4). We find that S47 cells exhibit decreased catabolic glycolysis but increased use of the pentose phosphate pathway (PPP), and an enhanced abundance of the antioxidant, NADPH. We identify ATF4 as differentially expressed in P47 and S47 cells and show that ATF4 can reverse the redox status and rescue metabolism of S47 cells, as well as increase sensitivity to ferroptosis. This adaptive metabolic switch is rapid, reversible, and accompanied by thiol-mediated changes in the structures and activities of key glycolytic signaling pathway proteins, including GAPDH and G6PD. The results presented here unveil the important functional interplay among pathways regulating thiol-redox status, metabolic adaptation, and cellular responses to oxidative stress.

The Warburg Effect 97 Years after Its Discovery

The deregulation of the oxidative metabolism in cancer, as shown by the increased aerobic glycolysis and impaired oxidative phosphorylation (Warburg effect), is coordinated by genetic changes leading to the activation of oncogenes and the loss of oncosuppressor genes. The understanding of the metabolic deregulation of cancer cells is necessary to prevent and cure cancer. In this review, we illustrate and comment the principal metabolic and molecular variations of cancer cells, involved in their anomalous behavior, that include modifications of oxidative metabolism, the activation of oncogenes that promote glycolysis and a decrease of oxygen consumption in cancer cells, the genetic susceptibility to cancer, the molecular correlations involved in the metabolic deregulation in cancer, the defective cancer mitochondria, the relationships between the Warburg effect and tumor therapy, and recent studies that reevaluate the Warburg effect. Taken together, these observations indicate that the Warburg effect is an epiphenomenon of the transformation process essential for the development of malignancy.

Targeting ferroptosis for cancer therapy: exploring novel strategies from its mechanisms and role in cancers

Ferroptosis is a novel form of non-apoptotic regulated cell death (RCD), with distinct characteristics and functions in physical conditions and multiple diseases such as cancers. Unlike apoptosis and autophagy, this new RCD is an iron-dependent cell death with features of lethal accumulation of reactive oxygen species (ROS) and over production of lipid peroxidation. Excessive iron from aberrant iron metabolisms or the maladjustment of the two main redox systems thiols and lipid peroxidation role as the major causes of ROS generation, and the redox-acrive ferrous (intracellular labile iron) is a crucial factor for the lipid peroxidation. Regulation of ferrroptosis also involves different pathways such as mevalonate pathway, P53 pathway and p62-Keap1-Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway. Ferroptosis roles as a double-edged sword either suppressing or promoting tumor progression with the release of multiple signaling molecules in the tumor microenvironment. Emerging evidence suggests ferroptosis as a potential target for cancer therapy and ferroptosis inducers including small molecules and nanomaterials have been developed. The application of ferroptosis inducers also relates to overcoming drug resistance and preventing tumor metastasis, and may become a promising strategy combined with other anti-cancer therapies. Here, we summarize the ferroptosis characters from its underlying basis and role in cancer, followed by its possible applications in cancer therapies and challenges maintained.

Overexpression of DGKI in Gastric Cancer Predicts Poor Prognosis

Background: Diacylglycerol kinase iota (DGKI) is overexpressed in a variety of cancers and is associated with poor prognosis in colon cancer. This study evaluated the prognostic value of DGKI in gastric cancer (GC) using data from The Cancer Genome Atlas (TCGA).

Methods: RNA sequencing results and clinical data of gastric adenoma and adenocarcinoma samples were obtained from the TCGA database (https://portal.gdc.cancer.gov). The Wilcoxon or Kruskal–Wallis test and logistic regression were used to analyze the relationship between DGKI and the clinicopathological characteristics of GC patients. Univariate Cox regression and Kaplan-Meier analysis were used to analyze the clinicopathological characteristics of GC patients and the relationship between DGKI and overall survival time, and multivariate Cox regression analysis was used to identify independent risk factors affecting the prognosis of GC patients. Gene set enrichment analysis (GSEA) was performed using the TCGA dataset.

Results: DGKI was overexpressed in gastric tumors and was related to poor prognosis (p = 0.003). Overexpression of DGKI in GC was significantly correlated with high grade (OR = 1.71 for G3 vs. G2), stage (OR = 2.08 for II vs. I) and T classification (OR = 4.64 for T4 vs. T1; OR = 3.99 for T3 vs. T1; OR = 3.37 for T2 vs. T1) (all p <0.05). DGKI (OR = 7.34; p = 0.000) was an independent risk factor affecting the survival of GC patients. The MAPK signaling pathway was differentially enriched with DGKI overexpression.

Conclusion: DGKI overexpression may be a potential molecular marker for poor prognosis in GC. The MAPK signaling pathway may be one of the key pathways related to DGKI regulation in GC.

USP22 promotes hypoxia-induced hepatocellular carcinoma stemness by a HIF1α/USP22 positive feedback loop upon TP53 inactivation

OBJECTIVE

We aimed to elucidate the mutual regulation mechanism of ubiquitin-specific protease 22 (USP22) and hypoxia inducible factor-1α (HIF1α), and the mechanism they promote the stemness of hepatocellular carcinoma (HCC) cells under hypoxic conditions.

DESIGN

Cell counting, migration, self-renewal ability, chemoresistance and expression of stemness genes were established to detect the stemness of HCC cells. Immunoprecipitation, ubiquitination assay and chromatin immunoprecipitation assay were used to elucidate the mutual regulation mechanism of USP22 and HIF1α. HCC patient samples and The Cancer Genome Atlas data were used to demonstrate the clinical significance. In vivo USP22-targeting experiment was performed in mice bearing HCC.

RESULTS

USP22 promotes hypoxia-induced HCC stemness and glycolysis by deubiquitinating and stabilising HIF1α. As direct target genes of HIF1α, USP22 and TP53 can be transcriptionally upregulated by HIF1α under hypoxic conditions. In TP53 wild-type HCC cells, HIF1α induced TP53-mediated inhibition of HIF1α-induced USP22 upregulation. In TP53-mutant HCC cells, USP22 and HIF1α formed a positive feedback loop and promote the stemness of HCC. HCC patients with a loss-of-function mutation at TP53 and high USP22 and/or HIF1α expression tend to have a worse prognosis. The USP22-targeting lipopolyplexes caused high tumour inhibition and high sorafenib sensitivity in mice bearing HCC.

CONCLUSION

USP22 promotes hypoxia-induced HCC stemness by a HIF1α/USP22 positive feedback loop on TP53 inactivation. USP22 is a promising target for the HCC therapy.

Mitochondrial metabolism and cancer metastasis

Metastasis is regarded as the most important cause of cancer-related deaths around the world. During the complicated metastatic cascade, altered mitochondrial metabolism adapts to serve distinct conditions and microenvironments. In this review, we discuss how cells regulate their mitochondria metabolism to adapt to environmental cues during the metastasis, as well as how cancer cells and their tumor micro-environment (TME) are metabolically coupled during the metastatic cascade. We place a strong emphasis on how mitochondrial proline metabolism and extracellular matrix (ECM) are coupled.