p53-mediated redox control promotes liver regeneration and maintains liver function in response to CCl4

Targeting tumor suppressor p53 for organ fibrosis therapy

Fibrosis is a reparative and progressive process characterized by abnormal extracellular matrix deposition, contributing to organ dysfunction in chronic diseases. The tumor suppressor p53 (p53), known for its regulatory roles in cell proliferation, apoptosis, aging, and metabolism across diverse tissues, appears to play a pivotal role in aggravating biological processes such as epithelial-mesenchymal transition (EMT), cell apoptosis, and cell senescence. These processes are closely intertwined with the pathogenesis of fibrotic disease. In this review, we briefly introduce the background and specific mechanism of p53, investigate the pathogenesis of fibrosis, and further discuss p53's relationship and role in fibrosis affecting the kidney, liver, lung, and heart. In summary, targeting p53 represents a promising and innovative therapeutic approach for the prevention and treatment of organ fibrosis.

Roles of reactive oxygen species in inflammation and cancer

Reactive oxygen species (ROS) constitute a spectrum of oxygenic metabolites crucial in modulating pathological organism functions. Disruptions in ROS equilibrium span various diseases, and current insights suggest a dual role for ROS in tumorigenesis and the immune response within cancer. This review rigorously examines ROS production and its role in normal cells, elucidating the subsequent regulatory network in inflammation and cancer. Comprehensive synthesis details the documented impacts of ROS on diverse immune cells. Exploring the intricate relationship between ROS and cancer immunity, we highlight its influence on existing immunotherapies, including immune checkpoint blockade, chimeric antigen receptors, and cancer vaccines. Additionally, we underscore the promising prospects of utilizing ROS and targeting ROS modulators as novel immunotherapeutic interventions for cancer. This review discusses the complex interplay between ROS, inflammation, and tumorigenesis, emphasizing the multifaceted functions of ROS in both physiological and pathological conditions. It also underscores the potential implications of ROS in cancer immunotherapy and suggests future research directions, including the development of targeted therapies and precision oncology approaches. In summary, this review emphasizes the significance of understanding ROS-mediated mechanisms for advancing cancer therapy and developing personalized treatments.

Genomic and transcriptomic profiling of hepatocellular carcinoma reveals a rare molecular subtype

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide, occurring predominantly in patients with underlying chronic liver disease and cirrhosis. Here, we describe a case of a 62-year-old man that was admitted to our hospital and diagnosed with HCC where the cancer has already metastasized to the retroperitoneum and peritoneum. In order to better characterize the HCC, both the cancerous liver tissue and the adjacent normal liver tissue of the patient were collected and subjected to a genomic, transcriptomic and proteomic analysis. Our patient carries a highly mutated HCC, which is characterized by both somatic mutation in the following genes ALK, CDK6, TP53, PGR. In addition, we observe several molecular alterations that are associated with potential therapy resistance, for example the expression of the organic-anion-transporting polypeptide (OATP) family members B1 and B3, that mediate the transport of the anticancer drugs, has been found decreased. Overall, our molecular profiling potentially classify the patient with poor prognosis and possibly displaying resistance to pharmacological therapy.

Harnessing metabolism of hepatic macrophages to aid liver regeneration

Liver regeneration is a dynamic and regulated process that involves inflammation, granulation, and tissue remodeling. Hepatic macrophages, abundantly distributed in the liver, are essential components that actively participate in each step to orchestrate liver regeneration. In the homeostatic liver, resident macrophages (Kupffer cells) acquire a tolerogenic phenotype and contribute to immunological tolerance. Following toxicity-induced damage or physical resection, Kupffer cells as well as monocyte-derived macrophages can be activated and promote an inflammatory process that supports the survival and activation of hepatic myofibroblasts and thus promotes scar tissue formation. Subsequently, these macrophages, in turn, exhibit the anti-inflammatory effects critical to extracellular matrix remodeling during the resolution stage. However, continuous damage-induced chronic inflammation generally leads to hepatic macrophage dysfunction, which exacerbates hepatocellular injury and triggers further liver fibrosis and even cirrhosis. Emerging macrophage-targeting strategies have shown efficacy in both preclinical and clinical studies. Increasing evidence indicates that metabolic rewiring provides substrates for epigenetic modification, which endows monocytes/macrophages with prolonged "innate immune memory". Therefore, it is reasonable to conceive novel therapeutic strategies for metabolically reprogramming macrophages and thus mediate a homeostatic or reparative process for hepatic inflammation management and liver regeneration.

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

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

Positive allosteric GABAA receptor modulation counteracts lipotoxicity-induced gene expression changes in hepatocytes in vitro

Introduction: We have previously shown that the novel positive allosteric modulator of the GABA_A receptor, HK4, exerts hepatoprotective effects against lipotoxicity-induced apoptosis, DNA damage, inflammation and ER stress in vitro. This might be mediated by downregulated phosphorylation of the transcription factors NF-κB and STAT3. The current study aimed to investigate the effect of HK4 on lipotoxicity-induced hepatocyte injury at the transcriptional level. Methods: HepG2 cells were treated with palmitate (200 μM) in the presence or absence of HK4 (10 μM) for 7 h. Total RNA was isolated and the expression profiles of mRNAs were assessed. Differentially expressed genes were identified and subjected to the DAVID database and Ingenuity Pathway Analysis software for functional and pathway analysis, all under appropriate statistical testing. Results: Transcriptomic analysis showed substantial modifications in gene expression in response to palmitate as lipotoxic stimulus with 1,457 differentially expressed genes affecting lipid metabolism, oxidative phosphorylation, apoptosis, oxidative and ER stress among others. HK4 preincubation resulted in the prevention of palmitate-induced dysregulation by restoring initial gene expression pattern of untreated hepatocytes comprising 456 genes. Out of the 456 genes, 342 genes were upregulated and 114 downregulated by HK4. Enriched pathways analysis of those genes by Ingenuity Pathway Analysis, pointed towards oxidative phosphorylation, mitochondrial dysregulation, protein ubiquitination, apoptosis, and cell cycle regulation as affected pathways. These pathways are regulated by the key upstream regulators TP53, KDM5B, DDX5, CAB39 L and SYVN1, which orchestrate the metabolic and oxidative stress responses including modulation of DNA repair and degradation of ER stress-induced misfolded proteins in the presence or absence of HK4. Discussion: We conclude that HK4 specifically targets mitochondrial respiration, protein ubiquitination, apoptosis and cell cycle. This not only helps to counteract lipotoxic hepatocellular injury through modification of gene expression, but - by targeting transcription factors responsible for DNA repair, cell cycle progression and ER stress - might even prevent lipotoxic mechanisms. These findings suggest that HK4 has a great potential for the treatment of non-alcoholic fatty liver disease (NAFLD).

Protein-Delivering Nanocomplexes with Fenton Reaction-Triggered Cargo Release to Boost Cancer Immunotherapy

Immunotherapeutic efficacy of tumors based on immune checkpoint blockade (ICB) therapy is frequently limited by an immunosuppressive tumor microenvironment and cross-reactivity with normal tissues. Herein, we develop reactive oxygen species (ROS)-responsive nanocomplexes with the function of ROS production for delivery and triggered release of anti-mouse programmed death ligand 1 antibody (αPDL1) and glucose oxidase (GOx). GOx and αPDL1 were complexed with oligomerized (-)-epigallocatechin-3-O-gallate (OEGCG), which was followed by chelation with Fe³⁺ and coverage of the ROS-responsive block copolymer, POEGMA-b-PTKDOPA, consisting of poly(oligo(ethylene glycol)methacrylate) (POEGMA) and the block with thioketal bond-linked dopamine moieties (PTKDOPA) as the side chains. After intravenous injection, the nanocomplexes show prolonged circulation in the bloodstream with a half-life of 8.72 h and efficient tumor accumulation. At the tumor sites, GOx inside the nanocomplexes can produce H₂O₂ via oxidation of glucose for Fenton reaction to generate hydroxyl radicals (•OH) which further trigger the release of the protein cargos through ROS-responsive cleavage of thioketal bonds. The released GOx improves the production efficiency of •OH to kill cancer cells for release of tumor-associated antigens via chemodynamic therapy (CDT). The enhanced immunogenic cell death (ICD) can activate the immunosuppressive tumor microenvironment and improve the immunotherapy effect of the released αPDL1, which significantly suppresses primary and metastatic tumors. Thus, the nanocomplexes with Fenton reaction-triggered protein release show great potentials to improve the immunotherapeutic efficacy of ICB via combination with CDT.

Centriole signaling restricts hepatocyte ploidy to maintain liver integrity

Hepatocyte polyploidization is a tightly controlled process that is initiated at weaning and increases with age. The proliferation of polyploid hepatocytes in vivo is restricted by the PIDDosome-P53 axis, but how this pathway is triggered remains unclear. Given that increased hepatocyte ploidy protects against malignant transformation, the evolutionary driver that sets the upper limit for hepatocyte ploidy remains unknown. Here we show that hepatocytes accumulate centrioles during cycles of polyploidization in vivo. The presence of excess mature centrioles containing ANKRD26 was required to activate the PIDDosome in polyploid cells. As a result, mice lacking centrioles in the liver or ANKRD26 exhibited increased hepatocyte ploidy. Under normal homeostatic conditions, this increase in liver ploidy did not impact organ function. However, in response to chronic liver injury, blocking centriole-mediated ploidy control leads to a massive increase in hepatocyte polyploidization, severe liver damage, and impaired liver function. These results show that hyperpolyploidization sensitizes the liver to injury, posing a trade-off for the cancer-protective effect of increased hepatocyte ploidy. Our results may have important implications for unscheduled polyploidization that frequently occurs in human patients with chronic liver disease.

Hepatic p53 is regulated by transcription factor FOXO1 and acutely controls glycogen homeostasis

The tumor suppressor p53 is involved in the adaptation of hepatic metabolism to nutrient availability. Acute deletion of p53 in the mouse liver affects hepatic glucose and triglyceride metabolism. However, long-term adaptations upon the loss of hepatic p53 and its transcriptional regulators are unknown. Here we show that short-term, but not chronic, liver-specific deletion of p53 in mice reduces liver glycogen levels, and we implicate the transcription factor forkhead box O1 protein (FOXO1) in the regulation of p53 and its target genes. We demonstrate that acute p53 deletion prevents glycogen accumulation upon refeeding, whereas a chronic loss of p53 associates with a compensational activation of the glycogen synthesis pathway. Moreover, we identify fasting-activated FOXO1 as a repressor of p53 transcription in hepatocytes. We show that this repression is relieved by inactivation of FOXO1 by insulin, which likely mediates the upregulation of p53 expression upon refeeding. Strikingly, we find that high-fat diet–induced insulin resistance with persistent FOXO1 activation not only blunted the regulation of p53 but also the induction of p53 target genes like p21 during fasting, indicating overlapping effects of both FOXO1 and p53 on target gene expression in a context-dependent manner. Thus, we conclude that p53 acutely controls glycogen storage in the liver and is linked to insulin signaling via FOXO1, which has important implications for our understanding of the hepatic adaptation to nutrient availability.

ESR1 Regulates the Obesity- and Metabolism-Differential Gene MMAA to Inhibit the Occurrence and Development of Hepatocellular Carcinoma

Obesity is often regarded as a factor that promotes tumorigenesis, but the role of obesity in promoting hepatocellular carcinoma (HCC) is still controversial. We compared the trend change of 14 obesity-related genes in the formation and development of HCC in normal, adjacent, and HCC tissues. Mendelian randomization (MR) analysis was used to verify the relationship between obesity and HCC occurrence. Metabolism of cobalamin-associated A (MMAA) was discovered as an obesity- and metabolism-differential gene, and its function in HCC was tested in vitro and in vivo. Finally, we explored how obese female patients with an originally high expression of female estrogen receptor (ESR1) directly upregulated MMAA to interfere with the progression of HCC. Fourteen obesity-related genes were downregulated in adjacent and tumoral tissues compared with normal liver tissues, which indicated that obesity may be inversely related to the occurrence of HCC and was consistent with the results of MR analysis. We also discovered that MMAA is a metabolic gene closely related to the occurrence and development of HCC by mining the TCGA database, and it functioned an anti-tumor-promoting role in HCC by damaging the mitochondrial function and preserving the redox balance. We further verified that obese females with a high expression of ESR1 can regulate MMAA to protect HCC from progression. This study elucidates that obesity might be a protective factor for female HCC patients, as they originally highly expressed ESR1, which could upregulate MMAA to suppress tumor growth and participate in metabolic reprogramming.

No Time to Die: How Kidney Cancer Evades Cell Death

The understanding of the pathogenesis of renal cell carcinoma led to the development of targeted therapies, which dramatically changed the overall survival rate. Nonetheless, despite innovative lines of therapy accessible to patients, the prognosis remains severe in most cases. Kidney cancer rarely shows mutations in the genes coding for proteins involved in programmed cell death, including p53. In this paper, we show that the molecular machinery responsible for different forms of cell death, such as apoptosis, ferroptosis, pyroptosis, and necroptosis, which are somehow impaired in kidney cancer to allow cancer cell growth and development, was reactivated by targeted pharmacological intervention. The aim of the present review was to summarize the modality of programmed cell death in the pathogenesis of renal cell carcinoma, showing in vitro and in vivo evidence of their potential role in controlling kidney cancer growth, and highlighting their possible therapeutic value.

Methyl 6-O-cinnamoyl-α-d-glucopyranoside Ameliorates Acute Liver Injury by Inhibiting Oxidative Stress Through the Activation of Nrf2 Signaling Pathway

Excessive stimulation of hepatotoxins and drugs often lead to acute liver injury, while treatment strategies for acute liver injury have been limited. Methyl 6-O-cinnamoyl-α-d-glucopyranoside (MCGP) is a structure modified compound from cinnamic acid, a key chemical found in plants with significant antioxidant, anti-inflammatory, and antidiabetic effects. In this study, we investigated the effects and underlying mechanisms of MCGP on acetaminophen (APAP)- or carbon tetrachloride (CCl₄)-induced acute liver injury. As a result, MCGP inhibited cell death and apoptosis induced by APAP or CCl₄, and suppressed the reactive oxygen species (ROS) generation stimulated by H₂O₂ in liver AML12 cells. In vivo, MCGP alleviated APAP/CCl₄-induced hepatic necrosis and resumed abnormal aminotransferase activities and liver antioxidase activities. In addition, MCGP depressed APAP- or CCl₄-induced oxidative stress through the suppression of CYP2E1 and activation of nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. MCGP also enhanced the number of PCNA-positive hepatocytes, increased hepatic PCNA and Bcl-XL, and decreased BAX expression in APAP-/CCl₄-intoxicated mice. Furthermore, MCGP activated the GSDMD-N/cleaved caspase 1 pathway. In summary, MCGP might act as a potential therapeutic drug against drug-induced and chemical-induced acute liver injuries, and its underlying mechanisms might engage on the pressing of oxidative stress, refraining of hepatocyte apoptosis, and facilitating of liver regeneration.

The role of ROS in tumour development and progression

Eukaryotic cells have developed complex systems to regulate the production and response to reactive oxygen species (ROS). Different ROS control diverse aspects of cell behaviour from signalling to death, and deregulation of ROS production and ROS limitation pathways are common features of cancer cells. ROS also function to modulate the tumour environment, affecting the various stromal cells that provide metabolic support, a blood supply and immune responses to the tumour. Although it is clear that ROS play important roles during tumorigenesis, it has been difficult to reliably predict the effect of ROS modulating therapies. We now understand that the responses to ROS are highly complex and dependent on multiple factors, including the types, levels, localization and persistence of ROS, as well as the origin, environment and stage of the tumours themselves. This increasing understanding of the complexity of ROS in malignancies will be key to unlocking the potential of ROS-targeting therapies for cancer treatment.