The role of tumor suppressor p53 in metabolism and energy regulation, and its implication in cancer and lifestyle-related diseases

MLIP and Its Potential Influence on Key Oncogenic Pathways

Muscle-enriched A-type lamin-interacting protein (MLIP) is an emerging protein involved in cellular homeostasis and stress adaptation. Eukaryotic cells regulate various cellular processes, including metabolism, DNA repair, and cell cycle progression, to maintain cellular homeostasis. Disruptions in this homeostasis can lead to diseases such as cancer, characterized by uncontrolled cell growth and division. This review aims to explore for the first time the unique role MLIP may play in cancer development and progression, given its interactions with the PI3K/Akt/mTOR pathway, p53, MAPK9, and FOXO transcription factors, all critical regulators of cellular homeostasis and tumor suppression. We discuss the current understanding of MLIP's involvement in pro-survival pathways and its potential implications in cancer cells' metabolic remodeling and dysregulated homeostasis. Additionally, we examine the potential of MLIP as a novel therapeutic target for cancer treatment. This review aims to shed light on MLIP's potential impact on cancer biology and contribute to developing innovative therapeutic strategies.

Multi-omics analyses of glucose metabolic reprogramming in colorectal cancer

Background

Glucose metabolic reprogramming (GMR) is a cardinal feature of carcinogenesis and metastasis. However, the underlying mechanisms have not been fully elucidated. The aim of this study was to profile the metabolic signature of primary tumor and circulating tumor cells from metastatic colorectal cancer (mCRC) patients using integrated omics analysis.

Methods

PET-CT imaging, serum metabolomics, genomics and proteomics data of 325 high 18F-fluorinated deoxyglucose (FDGhigh) mCRC patients were analyzed. The para-tumor, primary tumor and liver metastatic tissues of mCRC patients were used for proteomics analysis.

Results

The glucose uptake in tumor tissues as per the PET/CT images was correlated to serum levels of glutamic-pyruvic transaminase (ALT), total bilirubin (TBIL), creatinine (CRE). Proteomics analysis indicated that several differentially expressed proteins were enriched in both GMR and epithelial-mesenchymal transition (EMT)-related pathways. Using a tissue-optimized proteomic workflow, we identified novel proteomic markers (e.g. CCND1, EPCAM, RPS6), a novel PCK1-CDK6-INSR protein axis, and a potential role for FOLR (FR) in GMR/EMT of CRC cells. Finally, CEA/blood glucose (CSR) was defined as a new index, which can be used to jointly diagnose liver metastasis of colorectal cancer.

Conclusions

GMR in CRC cells is closely associated with the EMT pathway, and this network is a promising source of potential therapeutic targets.

Metabolic Reprogramming in Cancer Cells: Emerging Molecular Mechanisms and Novel Therapeutic Approaches

The constant changes in cancer cell bioenergetics are widely known as metabolic reprogramming. Reprogramming is a process mediated by multiple factors, including oncogenes, growth factors, hypoxia-induced factors, and the loss of suppressor gene function, which support malignant transformation and tumor development in addition to cell heterogeneity. Consequently, this hallmark promotes resistance to conventional anti-tumor therapies by adapting to the drastic changes in the nutrient microenvironment that these therapies entail. Therefore, it represents a revolutionary landscape during cancer progression that could be useful for developing new and improved therapeutic strategies targeting alterations in cancer cell metabolism, such as the deregulated mTOR and PI3K pathways. Understanding the complex interactions of the underlying mechanisms of metabolic reprogramming during cancer initiation and progression is an active study field. Recently, novel approaches are being used to effectively battle and eliminate malignant cells. These include biguanides, mTOR inhibitors, glutaminase inhibition, and ion channels as drug targets. This review aims to provide a general overview of metabolic reprogramming, summarise recent progress in this field, and emphasize its use as an effective therapeutic target against cancer.

MicroRNA-483-5p accentuates cisplatin-induced acute kidney injury by targeting GPX3

The ability of cisplatin (cis-diamminedichloroplatinum II) toxicity to induce acute kidney injury (AKI) has attracted attention and concern for a long time, but the molecular mechanism of action for cisplatin is not clear. MicroRNA-483 is involved in several diseases, such as tumorigenesis and osteoarthritis, but its renal target and potential role in AKI are unknown. In this study, we explored the pathogenic role and underlying mechanism of miR-483-5p in cisplatin-induced AKI, using transgenic mice, clinical specimen, and in vitro cell line. We found that miR-483-5p was significantly upregulated by cisplatin in a cisplatin-induced mouse model, in serum samples of patients who received cisplatin therapy, and in NRK-52E cells. Overexpression of miR-483-5p in mouse kidneys by stereotactic renal injection of lentiviruses mediated miR-483-5p or generation of conditional miR-483-overexpressing transgenic mice accentuated cisplatin-induced AKI by increasing oxidative stress, promoting apoptosis, and inhibiting autophagy of tubular cells. Furthermore, our results revealed miR-483-5p directly targeted to GPX3, overexpression of which rescued cisplatin-induced AKI by inhibiting oxidative stress and apoptosis of tubular cells, but not by regulating autophagy. Collectively, miR-483-5p is upregulated by cisplatin and exacerbates cisplatin-induced AKI via negative regulation of GPX3 and contributing oxidative stress and tubular cell apoptosis. These findings reveal a pathogenic role for miR-483-5p in cisplatin-induced AKI and suggest a novel target for the diagnosis and treatment of AKI.

Regulation of p53 Function by Formation of Non-Nuclear Heterologous Protein Complexes

A transcription factor p53 is activated upon cellular exposure to endogenous and exogenous stresses, triggering either homeostatic correction or cell death. Depending on the stress level, often measurable as DNA damage, the dual outcome is supported by p53 binding to a number of regulatory and metabolic proteins. Apart from the nucleus, p53 localizes to mitochondria, endoplasmic reticulum and cytosol. We consider non-nuclear heterologous protein complexes of p53, their structural determinants, regulatory post-translational modifications and the role in intricate p53 functions. The p53 heterologous complexes regulate the folding, trafficking and/or action of interacting partners in cellular compartments. Some of them mainly sequester p53 (HSP proteins, G6PD, LONP1) or its partners (RRM2B, PRKN) in specific locations. Formation of other complexes (with ATP2A2, ATP5PO, BAX, BCL2L1, CHCHD4, PPIF, POLG, SOD2, SSBP1, TFAM) depends on p53 upregulation according to the stress level. The p53 complexes with SIRT2, MUL1, USP7, TXN, PIN1 and PPIF control regulation of p53 function through post-translational modifications, such as lysine acetylation or ubiquitination, cysteine/cystine redox transformation and peptidyl-prolyl cis-trans isomerization. Redox sensitivity of p53 functions is supported by (i) thioredoxin-dependent reduction of p53 disulfides, (ii) inhibition of the thioredoxin-dependent deoxyribonucleotide synthesis by p53 binding to RRM2B and (iii) changed intracellular distribution of p53 through its oxidation by CHCHD4 in the mitochondrial intermembrane space. Increasing knowledge on the structure, function and (patho)physiological significance of the p53 heterologous complexes will enable a fine tuning of the settings-dependent p53 programs, using small molecule regulators of specific protein–protein interactions of p53.

The role of metabolic ecosystem in cancer progression — metabolic plasticity and mTOR hyperactivity in tumor tissues

Despite advancements in cancer management, tumor relapse and metastasis are associated with poor outcomes in many cancers. Over the past decade, oncogene-driven carcinogenesis, dysregulated cellular signaling networks, dynamic changes in the tissue microenvironment, epithelial-mesenchymal transitions, protein expression within regulatory pathways, and their part in tumor progression are described in several studies. However, the complexity of metabolic enzyme expression is considerably under evaluated. Alterations in cellular metabolism determine the individual phenotype and behavior of cells, which is a well-recognized hallmark of cancer progression, especially in the adaptation mechanisms underlying therapy resistance. In metabolic symbiosis, cells compete, communicate, and even feed each other, supervised by tumor cells. Metabolic reprogramming forms a unique fingerprint for each tumor tissue, depending on the cellular content and genetic, epigenetic, and microenvironmental alterations of the developing cancer. Based on its sensing and effector functions, the mechanistic target of rapamycin (mTOR) kinase is considered the master regulator of metabolic adaptation. Moreover, mTOR kinase hyperactivity is associated with poor prognosis in various tumor types. In situ metabolic phenotyping in recent studies highlights the importance of metabolic plasticity, mTOR hyperactivity, and their role in tumor progression. In this review, we update recent developments in metabolic phenotyping of the cancer ecosystem, metabolic symbiosis, and plasticity which could provide new research directions in tumor biology. In addition, we suggest pathomorphological and analytical studies relating to metabolic alterations, mTOR activity, and their associations which are necessary to improve understanding of tumor heterogeneity and expand the therapeutic management of cancer.

Orotic acid protects pancreatic β cell by p53 inactivation in diabetic mouse model

Impairment of pancreatic β cells is a principal driver of the development of diabetes. Restoring normal insulin release from the β cells depends on the ATP produced by the intracellular mitochondria. In maintaining mitochondrial function, the tumor suppressor p53 has emerged as a novel regulator of metabolic homeostasis and participates in adaptations to nutritional changes. In this study, we used orotic acid, an intermediate in the pathway for de novo synthesis of the pyrimidine nucleotide, to reduce genotoxicity. Administration of orotic acid reduced p53 activation of MIN6 β cells and subsequently reduced β cell death in the db/db mouse. Orotic acid intake helped to maintain the islet size, number of β cells, and protected insulin secretion in the db/db mouse. In conclusion, orotic acid treatment maintained β cell function and reduced cell death, and may therefore, be a future therapeutic strategy for the prevention and treatment of diabetes.

Network Pharmacology and Molecular Docking Analyses of Mechanisms Underlying Effects of the Cyperi Rhizoma-Chuanxiong Rhizoma Herb Pair on Depression

OBJECTIVE

We aimed to investigate the mechanisms underlying the effects of the Cyperi Rhizoma-Chuanxiong Rhizoma herb pair (CCHP) against depression using a network pharmacology approach.

METHODS

A network pharmacology approach, including screening of active compounds, target prediction, construction of a protein-protein interaction (PPI) network, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses, and molecular docking, molecular dynamics (MD) simulations, and molecular mechanics Poisson-Boltzmann surface area (MMPBSA), were used to explore the mechanisms of CCHP against depression.

RESULTS

Twenty-six active compounds and 315 and 207 targets of CCHP and depression, respectively, were identified. The PPI network suggested that AKT1, IL-6, TP53, DRD2, MAPK1, NR3C1, TNF, etc., were core targets. GO enrichment analyses showed that positive regulation of transcription from RNA polymerase II promoter, plasma membrane, and protein binding were of great significance. Neuroactive ligand-receptor interaction, PI3K-Akt signaling pathway, dopaminergic synapse, and mTOR signaling pathway were important pathways. Molecular docking results revealed good binding affinities for the core compounds and core targets. MD simulations and MMPBSA validated that quercetin can stably bind to 6hhi.

CONCLUSIONS

The effects of CCHP against depression involve multiple components, targets, and pathways, and these findings will promote further research on and clinical application of CCHP.

Lipid Catabolism and ROS in Cancer: A Bidirectional Liaison

Although cancer cell metabolism was mainly considered to rely on glycolysis, with the concomitant impairment of mitochondrial metabolism, it has recently been demonstrated that several tumor types are sustained by oxidative phosphorylation (OXPHOS). In this context, endogenous fatty acids (FAs) deriving from lipolysis or lipophagy are oxidised into the mitochondrion, and are used as a source of energy through OXPHOS. Because the electron transport chain is the main source of ROS, cancer cells relying on fatty acid oxidation (FAO) need to be equipped with antioxidant systems that maintain the ROS levels under the death threshold. In those conditions, ROS can act as second messengers, favouring proliferation and survival. Herein, we highlight the different responses that tumor cells adopt when lipid catabolism is augmented, taking into account the different ROS fates. Many papers have demonstrated that the pro- or anti-tumoral roles of endogenous FA usage are hugely dependent on the tumor type, and on the capacity of cancer cells to maintain redox homeostasis. In light of this, clinical studies have taken advantage of the boosting of lipid catabolism to increase the efficacy of tumor therapy, whereas, in other contexts, antioxidant compounds are useful to reduce the pro-survival effects of ROS deriving from FAO.

The Crosstalk Between Long Non-Coding RNAs and Various Types of Death in Cancer Cells

With the increasing aging population, cancer has become one of the leading causes of death worldwide, and the number of cancer cases and deaths is only anticipated to grow further. Long non-coding RNAs (lncRNAs), which are closely associated with the expression level of downstream genes and various types of bioactivity, are regarded as one of the key regulators of cancer cell proliferation and death. Cell death, including apoptosis, necrosis, autophagy, pyroptosis, and ferroptosis, plays a vital role in the progression of cancer. A better understanding of the regulatory relationships between lncRNAs and these various types of cancer cell death is therefore urgently required. The occurrence and development of tumors can be controlled by increasing or decreasing the expression of lncRNAs, a method which confers broad prospects for cancer treatment. Therefore, it is urgent for us to understand the influence of lncRNAs on the development of different modes of tumor death, and to evaluate whether lncRNAs have the potential to be used as biological targets for inducing cell death and predicting prognosis and recurrence of chemotherapy. The purpose of this review is to provide an overview of the various forms of cancer cell death, including apoptosis, necrosis, autophagy, pyroptosis, and ferroptosis, and to describe the mechanisms of different types of cancer cell death that are regulated by lncRNAs in order to explore potential targets for cancer therapy.

Proteomic Profiling of BRAFV600E Mutant Colon Cancer Cells Reveals the Involvement of Nucleophosmin/c-Myc Axis in Modulating the Response and Resistance to BRAF Inhibition by Vemurafenib

BRAFV600E mutations are found in approximately 10% of colorectal cancer patients and are associated with worse prognosis and poor outcomes with systemic therapies. The aim of this study was to identify novel druggable features of BRAFV600E-mutated colon cancer (CC) cells associated with the response and resistance to BRAFV600E inhibitor vemurafenib. Towards this aim, we carried out global proteomic profiling of BRAFV600E mutant vs. KRAS mutant/BRAF wild-type and double wild-type KRAS/BRAF CC cells followed by bioinformatics analyses. Validation of selected proteomic features was performed by immunohistochemistry and in silico using the TCGA database. We reveal an increased abundance and activity of nucleophosmin (NPM1) in BRAFV600E-mutated CC in vitro, in silico and in tumor tissues from colon adenocarcinoma patients and demonstrate the roles of NPM1 and its interaction partner c-Myc in conveying the resistance to vemurafenib. Pharmacological inhibition of NPM1 effectively restored the sensitivity of vemurafenib-resistant BRAF-mutated CC cells by down-regulating c-Myc expression and activity and consequently suppressing its transcriptional targets RanBP1 and phosphoserine phosphatase that regulate centrosome duplication and serine biosynthesis, respectively. Altogether, findings from this study suggest that the NPM1/c-Myc axis could represent a promising therapeutic target to thwart resistance to vemurafenib in BRAF-mutated CC.

Proteasome inhibitor MG132 induces apoptosis in human osteosarcoma U2OS cells

MG132 is a potent, reversible, and cell-permeable 20S proteasome inhibitor and it is derived from a Chinese medicinal plant. The purpose of this study is to investigate the anticancer effects of MG132 against human osteosarcoma U2OS cells. We first performed MTT and colony formation assays to investigate the anti-proliferative effects of MG132. The results demonstrated that MG132 suppressed the proliferation of U2OS cells. Furthermore, we found that treatment with MG132 increased apoptosis and induced DNA damage in U2OS cells. Additionally, zymography, wound healing, and invasion assays showed that MG132 suppressed the enzymatic activity of matrix metalloproteinases, cell migration, and invasion, respectively of U2OS cells. Furthermore, western blotting assay was performed to investigate the apoptotic signaling pathways in MG132-treated U2OS cells. Our results showed that MG132 downregulated the expression of antiapoptotic proteins, including CDK2, CDK4, Bcl-xL, and Bcl-2, whereas it upregulated the expression of proapoptotic proteins, including p21, p27, p53, p-p53 (ser15, ser20, and ser46), cleaved forms of caspase-3, caspase-7, caspase-9, and PARP, and FOXO3 in U2OS cells. These results demonstrated that MG132 activated apoptotic signaling pathways in U2OS cells. Interestingly, MG132 downregulated the phosphorylation of Akt and Erk. Taken together, our results suggest that MG132 has anticancer effects in U2OS cells. Therefore, MG132 may be a potential therapeutic agent for the treatment of osteosarcoma.

Methylglyoxal induces p53 activation and inhibits mTORC1 in human umbilical vein endothelial cells

Methylglyoxal (MGO), a precursor of advanced glycation end products (AGEs), is regarded as a pivotal mediator of vascular damage in patients with diabetes. We have previously reported that MGO induces transcriptional changes compatible with p53 activation in cultured human endothelial cells. To further substantiate this finding and to explore the underlying mechanisms and possible consequences of p53 activation, we aimed (1) to provide direct evidence for p53 activation in MGO-treated human umbilical vein endothelial cells (HUVECs), (2) to assess putative mechanisms by which this occurs, (3) to analyze down-stream effects on mTOR and autophagy pathways, and (4) to assess the potential benefit of carnosine herein. Exposure of HUVECs to 800 µM of MGO for 5 h induced p53 phosphorylation. This was paralleled by an increase in TUNEL and γ-H2AX positive cells, indicative for DNA damage. Compatible with p53 activation, MGO treatment resulted in cell cycle arrest, inhibition of mTORC1 and induction of autophagy. Carnosine co-treatment did not counteract MGO-driven effects. In conclusion, our results demonstrate that MGO elicits DNA damage and p53 activation in HUVECs, resulting in modulation of downstream pathways, e.g. mTORC1.

Effect of diabetes on exosomal miRNA profile in patients with obesity

INTRODUCTION

Obesity is a risk factor for type 2 diabetes mellitus (T2DM) and cardiovascular disease. T2DM increases the risk of cardiovascular-related death. We investigated changes in circulating exosomal microRNA (miRNA) profiles in patients with DM with obesity compared with patients without DM with obesity.

RESEARCH DESIGN AND METHODS

This prospective study involved 29 patients with obesity (patients without DM=16, patients with DM=13) and healthy volunteers (HVs) (n=18). We measured circulating levels of exosomal miRNAs by next-generation sequencing and compared miRNA levels across the three groups.

RESULTS

The expression levels of 25 miRNAs (upregulated=14, downregulated=11) differed between patients with obesity with DM and patients with obesity without DM. Compared with HV, patients with DM with obesity had 53 dysregulated miRNAs. Additionally, moving stepwise from HV to patients with obesity without DM to patients with obesity with DM, there was a consistent increase in expression levels of miR-23a-5p and miR-6087 and a consistent decrease in expressions levels of miR-6751-3p.

CONCLUSIONS

Our data show that the exosomal miRNAs is altered by dysregulated glucose metabolism in patients with obesity. This circulating exosomal miRNA signature in patients with obesity with or without DM is a potential biomarker and therapeutic target in these patients.

Lipids and cancer: Emerging roles in pathogenesis, diagnosis and therapeutic intervention

With the advent of effective tools to study lipids, including mass spectrometry-based lipidomics, lipids are emerging as central players in cancer biology. Lipids function as essential building blocks for membranes, serve as fuel to drive energy-demanding processes and play a key role as signaling molecules and as regulators of numerous cellular functions. Not unexpectedly, cancer cells, as well as other cell types in the tumor microenvironment, exploit various ways to acquire lipids and extensively rewire their metabolism as part of a plastic and context-dependent metabolic reprogramming that is driven by both oncogenic and environmental cues. The resulting changes in the fate and composition of lipids help cancer cells to thrive in a changing microenvironment by supporting key oncogenic functions and cancer hallmarks, including cellular energetics, promoting feedforward oncogenic signaling, resisting oxidative and other stresses, regulating intercellular communication and immune responses. Supported by the close connection between altered lipid metabolism and the pathogenic process, specific lipid profiles are emerging as unique disease biomarkers, with diagnostic, prognostic and predictive potential. Multiple preclinical studies illustrate the translational promise of exploiting lipid metabolism in cancer, and critically, have shown context dependent actionable vulnerabilities that can be rationally targeted, particularly in combinatorial approaches. Moreover, lipids themselves can be used as membrane disrupting agents or as key components of nanocarriers of various therapeutics. With a number of preclinical compounds and strategies that are approaching clinical trials, we are at the doorstep of exploiting a hitherto underappreciated hallmark of cancer and promising target in the oncologist's strategy to combat cancer.

Emerging Roles and Therapeutic Interventions of Aerobic Glycolysis in Glioma

Glioma is the most common type of intracranial malignant tumor, with a great recurrence rate due to its infiltrative growth, treatment resistance, intra- and intertumoral genetic heterogeneity. Recently, accumulating studies have illustrated that activated aerobic glycolysis participated in various cellular and clinical activities of glioma, thus influencing the efficacy of radiotherapy and chemotherapy. However, the glycolytic process is too complicated and ambiguous to serve as a novel therapy for glioma. In this review, we generalized the implication of key enzymes, glucose transporters (GLUTs), signalings and transcription factors in the glycolytic process of glioma. In addition, we summarized therapeutic interventions via the above aspects and discussed promising clinical applications for glioma.

Identification of a prognosis‑associated signature associated with energy metabolism in triple‑negative breast cancer

At present, a large number of exciting results have been found regarding energy metabolism within the triple-negative breast cancer (TNBC) field. Apart from aerobic glycolysis, a number of other catabolic pathways have also been demonstrated to participate in energy generation. However, the prognostic value of energy metabolism for TNBC currently remains unclear. In the present study, the association between gene expression profiles of energy metabolism and outcomes in patients with TNBC was examined using datasets obtained from the Gene Expression Omnibus and The Cancer Genome Atlas. In total, four robust TNBC subtypes were identified on the basis of negative matrix factorization clustering and gene expression patterns, which exhibited distinct immunological, molecular and prognostic (disease-free survival) features. The differentially expressed genes were subsequently identified from the subgroup that demonstrated the poorest prognosis compared with the remaining 3 subgroups, where their biological functions were assessed further by means of gene ontology enrichment analysis. Any signatures found to be associated with energy metabolism were then established using the Cox proportional hazards model to assess patient prognosis. According to results of Kaplan-Meier analysis, the constructed signature consisting of eight genes that were associated with energy metabolism distinguished patient outcomes into low- and high-risk groups. In addition, this signature, which was found to be markedly associated with the clinical characteristics of the patients, served as an independent factor in predicting TNBC patient prognosis. According to gene set enrichment analysis, the gene sets related to the high-risk group participated in the MAPK signal transduction pathway, focal adhesion and extracellular matrix receptor interaction, whilst those related to the low-risk group were revealed to be mainly associated with mismatch repair and propanoate metabolism. Findings from the present study shed new light on the role of energy metabolism within TNBC, where the eight-gene signature associated with energy metabolism constructed can be utilized as a new prognostic marker for predicting survival in patients with TNBC.

Perspective: Do Fasting, Caloric Restriction, and Diets Increase Sensitivity to Radiotherapy? A Literature Review

Caloric starvation, as well as various diets, has been proposed to increase the oxidative DNA damage induced by radiotherapy (RT). However, some diets could have dual effects, sometimes promoting cancer growth, whereas proposing caloric restriction may appear counterproductive during RT considering that the maintenance of weight is a major factor for the success of this therapy. A systematic review was performed via a PubMed search on RT and fasting, or caloric restriction, ketogenic diet (>75% of fat-derived energy intake), protein starvation, amino acid restriction, as well as the Warburg effect. Twenty-six eligible original articles (17 preclinical studies and 9 clinical noncontrolled studies on low-carbohydrate, high-fat diets popularized as ketogenic diets, representing a total of 77 patients) were included. Preclinical experiments suggest that a short period of fasting prior to radiation, and/or transient caloric restriction during treatment course, can increase tumor responsiveness. These regimens promote accumulation of oxidative lesions and insufficient repair, subsequently leading to cancer cell death. Due to their more flexible metabolism, healthy cells should be less sensitive, shifting their metabolism to support survival and repair. Interestingly, these regimens might stimulate an acute anticancer immune response, and may be of particular interest in tumors with high glucose uptake on positron emission tomography scan, a phenotype associated with poor survival and resistance to RT. Preclinical studies with ketogenic diets yielded more conflicting results, perhaps because cancer cells can sometimes metabolize fatty acids and/or ketone bodies. Randomized trials are awaited to specify the role of each strategy according to the clinical setting, although more stringent definitions of proposed diet, nutritional status, and consensual criteria for tumor response assessment are needed. In conclusion, dietary interventions during RT could be a simple and medically economical and inexpensive method that may deserve to be tested to improve efficiency of radiation.

The hallmarks of severe pulmonary arterial hypertension: the cancer hypothesis-ten years later

Severe forms of pulmonary arterial hypertension (PAH) are most frequently the consequence of a lumen-obliterating angiopathy. One pathobiological model is that the initial pulmonary vascular endothelial cell injury and apoptosis is followed by the evolution of phenotypically altered, apoptosis-resistant, proliferating cells and an inflammatory vascular immune response. Although there may be a vasoconstrictive disease component, the increased pulmonary vascular shear stress in established PAH is caused largely by the vascular wall pathology. In this review, we revisit the "quasi-malignancy concept" of severe PAH and examine to what extent the hallmarks of PAH can be compared with the hallmarks of cancer. The cancer model of severe PAH, based on the growth of abnormal vascular and bone marrow-derived cells, may enable the emergence of novel cell-based PAH treatment strategies.

Recent aspects of the effects of zinc on human health

Zinc (Zn) is one of the most important essential nutrients of great public health significance. It is involved in numerous biological functions and it is considered as a multipurpose trace element, due to its capacity to bind to more than 300 enzymes and more than 2000 transcriptional factors. Its role in biochemical pathways and cellular functions, such as the response to oxidative stress, homeostasis, immune responses, DNA replication, DNA damage repair, cell cycle progression, apoptosis and aging is significant. Zn is required for the synthesis of protein and collagen, thus contributing to wound healing and a healthy skin. Metallothioneins are metal-binding proteins and they are potent scavengers of heavy metals, including Zn, and protect the organism against stress. Zn deficiency is observed almost in 17% of the global population and affects many organ systems, leading to dysfunction of both humoral and cell-mediated immunity, thus increasing the susceptibility to infection. This review gives a thorough insight into the most recent evidence on the association between Zn biochemistry and human pathologies, epigenetic processes, gut microbial composition, drug targets and nanomedicine.

Inhibition of APE1-endonuclease activity affects cell metabolism in colon cancer cells via a p53-dependent pathway

The pathogenesis of colorectal cancer (CRC) involves different mechanisms, such as genomic and microsatellite instabilities. Recently, a contribution of the base excision repair (BER) pathway in CRC pathology has been emerged. In this context, the involvement of APE1 in the BER pathway and in the transcriptional regulation of genes implicated in tumor progression strongly correlates with chemoresistance in CRC and in more aggressive cancers. In addition, the APE1 interactome is emerging as an important player in tumor progression, as demonstrated by its interaction with Nucleophosmin (NPM1). For these reasons, APE1 is becoming a promising target in cancer therapy and a powerful prognostic and predictive factor in several cancer types. Thus, specific APE1 inhibitors have been developed targeting: i) the endonuclease activity; ii) the redox function and iii) the APE1-NPM1 interaction. Furthermore, mutated p53 is a common feature of advanced CRC. The relationship between APE1 inhibition and p53 is still completely unknown. Here, we demonstrated that the inhibition of the endonuclease activity of APE1 triggers p53-mediated effects on cell metabolism in HCT-116 colon cancer cell line. In particular, the inhibition of the endonuclease activity, but not of the redox function or of the interaction with NPM1, promotes p53 activation in parallel to sensitization of p53-expressing HCT-116 cell line to genotoxic treatment. Moreover, the endonuclease inhibitor affects mitochondrial activity in a p53-dependent manner. Finally, we demonstrated that 3D organoids derived from CRC patients are susceptible to APE1-endonuclease inhibition in a p53-status correlated manner, recapitulating data obtained with HCT-116 isogenic cell lines. These findings suggest the importance of further studies aimed at testing the possibility to target the endonuclease activity of APE1 in CRC.