Sea buckthorn extract mitigates chronic obstructive pulmonary disease by suppression of ferroptosis via scavenging ROS and blocking p53/MAPK pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: Sea buckthorn (Hippophae rhamnoides), a traditional Tibetan medicinal herb, exhibits protective effects against cardiovascular and respiratory diseases. Although Sea buckthorn extract (SBE) has been confirmed to alleviate airway inflammation in mice, its therapeutic effect and underlying mechanism on chronic obstructive pulmonary disease (COPD) requires further clarification. AIM OF THE STUDY: To elucidate the alleviative effect and molecular mechanism of SBE on lipopolysaccharides (LPS)/porcine pancreatic elastase (PPE)-induced COPD by blocking ferroptosis. METHODS: The anti-ferroptotic effects of SBE were evaluated in human BEAS-2B bronchial epithelial cells using CCK8, RT-qPCR, western blotting, and transmission electron microscopy. Transwell was employed to detect chemotaxis of neutrophils. COPD model was induced by intranasally administration of LPS/PPE in mice and measured by alterations of histopathology, inflammation, and ferroptosis. RNA-sequencing, western blotting, antioxidant examination, flow cytometry, DARTS, CETSA, and molecular docking were then used to investigate its anti-ferroptotic mechanisms. RESULTS: In vitro, SBE not only suppressed erastin- or RSL3-induced ferroptosis by suppressing lipid peroxides (LPOs) production and glutathione (GSH) depletion, but also suppressed ferroptosis-induced chemotactic migration of neutrophils via reducing mRNA expression of chemokines. In vivo, SBE ameliorated LPS/PPE-induced COPD phenotypes, and inhibited the generation of LPOs, cytokines, and chemokines. RNA-sequencing showed that p53 pathway and mitogen-activated protein kinases (MAPK) pathway were implicated in SBE-mediated anti-ferroptotic action. SBE repressed erastin- or LPS/PPE-induced overactivation of p53 and MAPK pathway, thereby decreasing expression of diamine acetyltransferase 1 (SAT1) and arachidonate 15-lipoxygenase (ALOX15), and increasing expression of glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11). Mechanistically, erastin-induced elevation of reactive oxygen species (ROS) was reduced by SBE through directly scavenging free radicals, thereby contributing to its inhibition of p53 and MAPK pathways. CETSA, DARTS, and molecular docking further showed that ROS-generating enzyme nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4) may be the target of SBE. Overexpression of NOX4 partially impaired the anti-ferroptotic activity of SBE. CONCLUSION: Our results demonstrated that SBE mitigated COPD by suppressing p53 and MAPK pro-ferroptosis pathways via directly scavenging ROS and blocking NOX4. These findings also supported the clinical application of Sea buckthorn in COPD therapy.

Copy number amplification-induced overexpression of lncRNA LOC101927668 facilitates colorectal cancer progression by recruiting hnRNPD to disrupt RBM47/p53/p21 signaling.

BACKGROUND: Somatic copy number alterations (SCNAs) are pivotal in cancer progression and patient prognosis. Dysregulated long non-coding RNAs (lncRNAs), modulated by SCNAs, significantly impact tumorigenesis, including colorectal cancer (CRC). Nonetheless, the functional significance of lncRNAs induced by SCNAs in CRC remains largely unexplored. METHODS: The dysregulated lncRNA LOC101927668, induced by copy number amplification, was identified through comprehensive bioinformatic analyses utilizing multidimensional data. Subsequent in situ hybridization was employed to ascertain the subcellular localization of LOC101927668, and gain- and loss-of-function experiments were conducted to elucidate its role in CRC progression. The downstream targets and signaling pathway influenced by LOC101927668 were identified and validated through a comprehensive approach, encompassing RNA sequencing, RT-qPCR, Western blot analysis, dual-luciferase reporter assay, evaluation of mRNA and protein degradation, and rescue experiments. Analysis of AU-rich elements (AREs) within the mRNA 3' untranslated region (UTR) of the downstream target, along with exploration of putative ARE-binding proteins, was conducted. RNA pull-down, mass spectrometry, RNA immunoprecipitation, and dual-luciferase reporter assays were employed to elucidate potential interacting proteins of LOC101927668 and further delineate the regulatory mechanism between LOC101927668 and its downstream target. Moreover, subcutaneous xenograft and orthotopic liver xenograft tumor models were utilized to evaluate the in vivo impact of LOC101927668 on CRC cells and investigate its correlation with downstream targets. RESULTS: Significantly overexpressed LOC101927668, driven by chr7p22.3-p14.3 amplification, was markedly correlated with unfavorable clinical outcomes in our CRC patient cohort, as well as in TCGA and GEO datasets. Moreover, we demonstrated that enforced expression of LOC101927668 significantly enhanced cell proliferation, migration, and invasion, while its depletion impeded these processes in a p53-dependent manner. Mechanistically, nucleus-localized LOC101927668 recruited hnRNPD and translocated to the cytoplasm, accelerating the destabilization of RBM47 mRNA, a transcription factor of p53. As a nucleocytoplasmic shuttling protein, hnRNPD mediated RBM47 destabilization by binding to the ARE motif within RBM47 3'UTR, thereby suppressing the p53 signaling pathway and facilitating CRC progression. CONCLUSIONS: The overexpression of LOC101927668, driven by SCNAs, facilitates CRC proliferation and metastasis by recruiting hnRNPD, thus perturbing the RBM47/p53/p21 signaling pathway. These findings underscore the pivotal roles of LOC101927668 and highlight its therapeutic potential in anti-CRC interventions.

Sirtuin 1 in regulating the p53/glutathione peroxidase 4/gasdermin D axis in acute liver failure.

In this editorial, we comment on the article by Zhou et al. The study reveals the connection between ferroptosis and pyroptosis and the effect of silent information regulator sirtuin 1 (SIRT1) activation in acute liver failure (ALF). ALF is characterized by a sudden and severe liver injury resulting in significant hepatocyte damage, often posing a high risk of mortality. The predominant form of hepatic cell death in ALF involves apoptosis, ferroptosis, autophagy, pyroptosis, and necroptosis. Glutathione peroxidase 4 (GPX4) inhibition sensitizes the cell to ferroptosis and triggers cell death, while Gasdermin D (GSDMD) is a mediator of pyroptosis. The study showed that ferroptosis and pyroptosis in ALF are regulated by blocking the p53/GPX4/GSDMD pathway, bridging the gap between the two processes. The inhibition of p53 elevates the levels of GPX4, reducing the levels of inflammatory and liver injury markers, ferroptotic events, and GSDMD-N protein levels. Reduced p53 expression and increased GPX4 on deletion of GSDMD indicated ferroptosis and pyroptosis interaction. SIRT1 is a NAD-dependent deacetylase, and its activation attenuates liver injury and inflammation, accompanied by reduced ferroptosis and pyroptosis-related proteins in ALF. SIRT1 activation also inhibits the p53/GPX4/GSDMD axis by inducing p53 acetylation, attenuating LPS/D-GalN-induced ALF.

Targeting both ferroptosis and pyroptosis may represent potential therapies for acute liver failure.

In this editorial, we comment on the article published in the recent issue of the World Journal of Gastroenterology. Acute liver failure (ALF) is a fatal disease that causes uncontrolled massive hepatocyte death and rapid loss of liver function. Ferroptosis and pyroptosis, cell death forms that can be initiated or blocked concurrently, can play significant roles in developing inflammation and various malignancies. However, their roles in ALF remain unclear. The article discovered the positive feedback between ferroptosis and pyroptosis in the progression of ALF, and revealed that the silent information regulator sirtuin 1 (SIRT1) inhibits both pathways through p53, dramatically reducing inflammation and protecting hepatocytes. This suggests the potential use of SIRT1 and its downstream molecules as therapeutics for ALF. Thus, we will discuss the role of ferroptosis and pyroptosis in ALF and the crosstalk between these cell death mechanisms. Additionally, we address potential treatments that could alleviate ALF by simultaneously inhibiting both cell death pathways, as well as examples of SIRT1 activators being used as disease treatment strategies, providing new insights into the therapy of ALF.

Prognostic and predictive significance of p53 and ATRX in neuroendocrine neoplasms of GIT and pancreas and their utility as an adjunct to accurate diagnosis-An eight-year retrospective study.

INTRODUCTION: Neuroendocrine neoplasms of gastrointestinal tract (GIT) and pancreas are heterogenous tumors. World Health Organization (WHO) 2019 classification introduced Grade (G)3 neuroendocrine tumor (NET) distinct from neuroendocrine carcinoma (NEC), based on molecular differences and to triage the patients for appropriate therapy. This distinction largely relies on morphology, which can be challenging at times. Genomic profiling has revealed TP53 and RB1 mutations in NECs, while death domain-associated protein 6 (DAXX) and alpha-thalassemia/mental retardation X-linked (ATRX), in G3NET. Their role as biological markers in differentiating these entities and their significance as prognostic markers are not yet established. This study aims at analyzing the diagnostic and prognostic role of p53 and ATRX in neuroendocrine neoplasms of GIT and pancreas. METHODOLOGY: A single-centre, eight-year retrospective study of neuroendocrine neoplasm of GIT and pancreas comprised G2NET, G3NET and NEC. Tumor slides were stained by immunohistochemistry for p53 and ATRX. Strong nuclear staining of > 50% of tumor cells for p53 was considered mutated. Nuclear staining of ATRX in < 5% of tumor cells was considered ATRX loss. Expression of p53 and ATRX was analyzed and correlated with tumor grades and patient survival. RESULTS: Fifty-five patients with gastro-entero-pancreatic neuroendocrine neoplasm were studied, comprising G2NET (58%), G3NET (16%) and NEC (26%). Median age of diagnosis was 59 years with male predominance. The pancreas was the most common site followed by the small bowel. NEC showed lower survival compared to G3 and G2NET. Mutated p53 immunohistochemical expression was more frequent among NEC than G3NET. Patients with mutated p53 had significantly lower survival irrespective of the grade (p = 0.001). There was no association of ATRX loss with grade or survival. CONCLUSION: G3NETs are genetically different from NECs. Use of immunohistochemistry for p53 in addition to histomorphology may facilitate accurate categorization of NEC and G3NET. Mutated p53 may also be used as an independent prognostic marker in neuroendocrine tumors of GIT and pancreas.

Exploring the MRI and Clinical Features of P53-Mutated Hepatocellular Carcinoma.

Purpose: To study the MRI features (based on LI-RADS) and clinical characteristics of P53-mutated hepatocellular carcinoma (HCC) patients. Patients and Methods: This study enrolled 344 patients with histopathologically confirmed HCC (P53-mutated group [n = 196], non-P53-mutated group [n = 148]). We retrospectively evaluated the preoperative MRI features, clinical and pathologic features of the lesions and assigned each lesion according to the LI-RADS. MRI findings, clinical features, and pathologic findings were compared using the Student's t test, χ2 test, and multivariable regression analysis. Results: Most HCC patients were categorized as LR-5. On multivariate analysis, the Edmondson-Steiner grade (odds ratio, 2.280; 95% CI: 1.268, 4.101; p = 0.006) and rim enhancement (odds ratio, 2.517; 95% CI: 1.095, 5.784; p = 0.030) were found to be independent variables associated with P53-mutated HCC. In the group of HCC lesions with the largest tumor diameter (LTD) greater than or equal to 10mm and less than or equal to 20mm, enhancing capsule was an independent predictor of P53-mutated HCC (odds ratio, 6.200; 95% CI: 1.116, 34.449; p = 0.037). Among the HCC lesions (20 mm ˂ LTD ≤ 50 mm), corona enhancement (odds ratio, 2.102; 95% CI: 1.022, 4.322; p = 0.043) and nodule-in-nodule architecture (odds ratio, 2.157; 95% CI: 1.033, 4.504; p = 0.041) were found to be independent risk factors for P53 mutation. Among the HCC lesions (50 mm ˂ LTD ≤ 100 mm), diameter (odds ratio, 1.035; 95% CI: 1.001, 1.069; p = 0.044) and AFP ≥ 400 (ng/mL) (odds ratio, 3.336; 95% CI: 1.052, 10.577; p = 0.041) were found to be independent variables associated with P53-mutated HCC. Conclusion: Poor differentiation and rim enhancement are potential predictive biomarkers for P53-mutated HCC, while HCCs of different diameters have different risk factors for predicting P53 mutations.

CSP7 Protects Alveolar Epithelial Cells by Targeting p53-Fibrinolytic Pathways During Lung Injuries.

Impaired alveolar epithelial regeneration in patients with idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) is attributed to telomere dysfunction in type II alveolar epithelial cells (A2Cs). Genetic susceptibility, aging, and toxicant exposures, including tobacco smoke (TS), contribute to telomere dysfunction in A2Cs. Here we investigated whether improvement of telomere function plays a role in CSP7-mediated protection of A2Cs against ongoing senescence and apoptosis during bleomycin (BLM)-induced pulmonary fibrosis (PF) as well as alveolar injury caused by chronic TS exposure. We found a significant telomere shortening in A2Cs isolated from IPF and COPD lungs in line with other studies. These cells showed increased p53 in addition to its post-translational modification with induction of activated caspase-3 and ß-galactosidase, suggesting a p53-mediated loss of A2C renewal. Further, we found increased expression of SIAH-1, a p53-inducible E3 ubiquitin ligase known to down-regulate telomere repeats binding factor 2 (TRF2). Consistent with the loss of TRF2 and upregulation of TRF1, telomerase reverse transcriptase (TERT) was downregulated in A2Cs. A2Cs from fibrotic lungs of mice either repeatedly instilled with BLM or isolated from chronic TS exposure-induced lung injury model showed reduced telomere length along with induction of p53, PAI-1, SIAH1 and TRF1 as well as loss of TRF2 and TERT, which were reversed in wild-type mice after treatment with CSP7. Interestingly, PAI-1-/- mice, or those lacking microRNA-34a expression in A2Cs, resisted telomere dysfunction, while uPA-/- mice failed to respond to CSP7 treatment, suggesting p53-microRNA-34a feed-forward induction and p53-uPA pathway contributes to telomere dysfunction.

Exploring the therapeutic potential of simvastatin in pancreatic neuroendocrine neoplasms: insights into cell cycle regulation and apoptosis.

Background: Pancreatic neuroendocrine neoplasm (pNEN) poses significant challenges in clinical management due to their heterogeneity and limited treatment options. In this study, we investigated the potential of simvastatin (SIM) as an anti-tumor agent in pNEN. Methods: We conducted cell culture experiments using QGP-1 and BON-1 cell lines and assessed cell viability, proliferation, migration, and invasion following SIM treatment. To further validate our findings, we performed in vivo experiments using a mouse xenograft model. Additionally, we investigated the underlying molecular mechanisms by analyzing changes in cell cycle progression, apoptosis, and signaling pathways. Results: SIM treatment suppresses pNEN growth both in vitro and in vivo, and led to G1 phase arrest in QGP-1 cells. In contrast, SIM affected both the G1-S and G2-M phase transitions in the BON-1 cell line and induced apoptosis, indicating diverse mechanisms of action. Furthermore, SIM treatment resulted in decreased expression of mutant p53 (mutp53) in BON-1 cells, suggesting a potential therapeutic strategy targeting mutp53. Modulation of the MAPK pathway was also implicated in QGP-1 cells. Conclusions: Our study highlights SIM as a promising candidate for pNEN treatment by inducing cell cycle arrest or apoptosis, potentially through the p53 and MAPK pathways. Further research is warranted to fully elucidate SIM's mechanisms of action and evaluate its therapeutic potential in clinical settings.

MDM2 inhibitors in cancer immunotherapy: Current status and perspective.

Murine double minute 2 (MDM2) plays an essential role in the cell cycle, apoptosis, DNA repair, and oncogene activation through p53-dependent and p53-independent signaling pathways. Several preclinical studies have shown that MDM2 is involved in tumor immune evasion. Therefore, MDM2-based regulation of tumor cell-intrinsic immunoregulation and the immune microenvironment has attracted increasing research attention. In recent years, immune checkpoint inhibitors targeting PD-1/PD-L1 have been widely used in the clinic. However, the effectiveness of a single agent is only approximately 20%-40%, which may be related to primary and secondary drug resistance caused by the dysregulation of oncoproteins. Here, we reviewed the role of MDM2 in regulating the immune microenvironment, tumor immune evasion, and hyperprogression during immunotherapy. In addition, we summarized preclinical and clinical findings on the use of MDM2 inhibitors in combination with immunotherapy in tumors with MDM2 overexpression or amplification. The results reveal that the inhibition of MDM2 could be a promising strategy for enhancing immunotherapy.

Therapeutic effects of focused ultrasound on vulvar squamous intraepithelial lesions in rat.

OBJECTIVE: In this study, we established a Sprague-Dawley rat model of vulvar squamous intraepithelial lesions and investigated the impact of focused ultrasound on the expression of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) and mutant type p53 (mtp53) in the vulvar skin of rats with low-grade squamous intraepithelial lesions (LSIL). MATERIALS AND METHODS: The vulvar skin of 60 rats was treated with dimethylbenzanthracene (DMBA) and mechanical irritation three times a week for 14 weeks. Rats with LSIL were randomly allocated into the experimental group or the control group. The experimental group was treated with focused ultrasound, while the control group received sham treatment. RESULTS: After 14 weeks treatment of DMBA combined with mechanical irritation, LSIL were observed in 44 (73.33%) rats, and high-grade squamous intraepithelial lesions (HSIL) were observed in 14 (23.33%) rats. 90.91% (20/22) of rats showed normal pathology and 9.09% (2/22) of rats exhibited LSIL in the experimental group at four weeks after focused ultrasound treatment. 22.73% (5/22) of rats exhibited LSIL, 77.27% (17/22) of rats progressed to HSIL in the control group. Compared with the control-group rats, the levels of HIF-1α, VEGF and mtp53 were significantly decreased in experimental-group rats (p < 0.05). CONCLUSIONS: These results indicate that DMBA combined with mechanical irritation can induce vulvar squamous intraepithelial lesion in SD rats. Focused ultrasound can treat LSIL safely and effectively, prevent the progression of vulvar lesions, and improve the microenvironment of vulvar tissues by decreasing the localized expression of HIF-1α, VEGF, and mtp53 in rats.

SRBD1 Regulates the Cell Cycle, Apoptosis, and M2 Macrophage Polarization via the RPL11-MDM2-p53 Pathway in Glioma.

Low expression of certain ribosomal proteins leads to the inactivation of p53, which is mediated mainly by RPL5 or RPL11 (ribosomal protein L11). It is also unknown what mechanisms drive aberrant ribosomal proteins expression in tumor. SRBD1 (S1 RNA-binding domain 1), as a highly conserved RNA-binding protein, is lowly expressed in glioma tissues and correlated with glioma prognosis. In this study, we observed that SRBD1 was closely related to p53 signaling. The upregulation of SRBD1 elevated p53 levels, thereby activating the p53 signaling pathway. As an RNA bind protein, SRBD1 could bind to the 5'-UTR of target genes and regulate RNA translation. We further conducted RNA immunoprecipitation using anti-SRDB1 antibody and noticed 29 hub RNA, including RPL11. RPL11 could inhibit MDM2-mediated p53 ubiquitination. SRBD1 upregulation promoted RPL11 binding to MDM2 via elevating RPL11 protein levels, which in turn activated the p53 signaling. Disrupting the p53 signaling blocked SRBD1-induced glioma suppression. In mouse xenograft model, SRBD1 ectopic expression was effective in reducing the total M2 tumor-associated macrophages (TAMs) density and suppressed glioma tumor growth. In summary, these data show that SRBD1 has a critical role in inhibition of glioma tumor growth and M2 macrophage polarization, and targeting RPL11-MDM2-p53 signaling may be an effective strategy to improve therapy and survival for glioma patients.

miR-19a-3p promotes the growth of hepatocellular carcinoma by regulating p53/SOX4.

Objective: This study aims to investigate the potential functions of miR-19a-3p in HCC. Method: We collected serum samples to analyze miR-19a-3p expression. We utilized CCK8 and Transwell assays to access miR-19a-3p's influence on HCC cells malignancy. We used dual-luciferase reporter and western blotting to validate the impact of p53/miR-19 on miR-19/SOX4. Results: The results demonstrated that miR-19a-3p was highly expressed in pre-operative serum samples and HCC cells, which can promote cell proliferation, migration and invasion in HCC under in vitro conditions. Additionally, there was a p53 binding site on the upstream of miR-19a-3p, which was inhibited by p53. SOX4 was the direct gene targeted by miR-19a-3p. The imbalance of p53-miR-19-SOX4 loop was one reason for the progress of HCC. Conclusion: Our findings validate the mechanisms of miR-19a-3p and highlight its potential as a therapeutic target in HCC.

Identification of TPI1 As a potential therapeutic target in pancreatic cancer with dependency of TP53 mutation using multi-omics analysis.

Mutations of KRAS, CDKN2A, TP53, and SMAD4 are the four major driver genes for pancreatic ductal adenocarcinoma (PDAC), of which mutations of KRAS and TP53 are the most frequently recognized. However, molecular-targeted therapies for mutations of KRAS and TP53 have not yet been developed. To identify novel molecular targets, we newly established organoids with the Kras mutation (KrasmuOR) and Trp53 loss of function using Cre transduction and CRISPR/Cas9 (Krasmu/p53muOR) from murine epithelia of the pancreatic duct in KrasLSL-G12D mice, and then analyzed the proteomic and metabolomic profiles in both organoids by mass spectrometry. Hyperfunction of the glycolysis pathway was recognized in Krasmu/p53muOR compared with KrasmuOR. Loss of function of triosephosphate isomerase (TPI1), which is involved in glycolysis, induced a reduction of cell proliferation in human PDAC cell lines with the TP53 mutation, but not in PDAC or in human fibroblasts without TP53 mutation. The TP53 mutation is clinically recognized in 70% of patients with PDAC. In the present study, protein expression of TPI1 and nuclear accumulation of p53 were recognized in the same patients with PDAC. TPI1 is a potential candidate therapeutic target for PDAC with the TP53 mutation.

Molecular Events in Response to Triclosan-Induced Oxidative Stress in CRISPR/Cas9-Mediated p53-Targeted Mutants in Daphnia magna.

Triclosan (TCS), a widely used antimicrobial agent, has been implicated in the oxidative stress induction and disruption of cellular processes in aquatic organisms. As TCS is ubiquitous in the aquatic environment, many previous studies have documented the effects of exposure to TCS on aquatic organisms. Nevertheless, most of the research has concentrated on the molecular and physiological responses of TCS, but there are still limited studies on the function of specific genes and the consequences of their absence. In this study, we focused on p53, a gene that is crucial for molecular responses such as autophagy and apoptosis as a result of TCS exposure. In order to ascertain the role and impact of the p53 gene in TCS-induced molecular responses, we examined the molecular responses to TCS-induced oxidative stress in wild-type (WT) and CRISPR/Cas9-mediated p53 mutant (MT) water fleas. The result has been accomplished by examining changes in molecular mechanisms, including in vivo end points, enzyme activities, adenosine triphosphate release rate, and apoptosis, to determine the role and impact of the p53 gene on TCS-induced molecular responses. The results indicated that the sensitivity of MT water fleas to TCS was greater than that of WT water fleas; however, the difference in sensitivity was significant at short exposures within 48 h and decreased toward 48 h. Accordingly, when we confirmed the oxidative stress after 24 h of exposure, the oxidative stress to TCS exposure was stronger in the MT group, with an imbalance of redox. To identify the mechanisms of tolerance to TCS in WT and MT Daphnia magna, we checked mitochondrial and ER-stress-related biomarkers and found an increase in apoptosis and greater sensitivity to TCS exposure in the MT group than in the WT. Our results suggest that the absence of p53 caused alterations in molecular processes in response to TCS exposure, resulting in increased sensitivity to TCS, and that p53 plays a critical role in response to TCS exposure.

Inverse correlation between TP53 gene status and PD-L1 protein levels in a melanoma cell model depends on an IRF1/SOX10 regulatory axis.

BACKGROUND: PD-L1 expression on cancer cells is an important mechanism of tumor immune escape, and immunotherapy targeting the PD-L1/PD1 interaction is a common treatment option for patients with melanoma. However, many patients do not respond to treatment and novel predictors of response are emerging. One suggested modifier of PD-L1 is the p53 pathway, although the relationship of p53 pathway function and activation is poorly understood. METHODS: The study was performed on human melanoma cell lines with various p53 status. We investigated PD-L1 and proteins involved in IFNγ signaling by immunoblotting and mRNA expression, as well as membrane expression of PD-L1 by flow cytometry. We evaluated differences in the ability of NK cells to recognize and kill target tumor cells on the basis of p53 status. We also investigated the influence of proteasomal degradation and protein half-life, IFNγ signaling and p53 activation on biological outcomes, and performed bioinformatic analysis using available data for melanoma cell lines and melanoma patients. RESULTS: We demonstrate that p53 status changes the level of membrane and total PD-L1 protein through IRF1 regulation and show that p53 loss influences the recently discovered SOX10/IRF1 regulatory axis. Bioinformatic analysis identified a dependency of SOX10 on p53 status in melanoma, and a co-regulation of immune signaling by both transcription factors. However, IRF1/PD-L1 regulation by p53 activation revealed complicated regulatory mechanisms that alter IRF1 mRNA but not protein levels. IFNγ activation revealed no dramatic differences based on TP53 status, although dual p53 activation and IFNγ treatment confirmed a complex regulatory loop between p53 and the IRF1/PD-L1 axis. CONCLUSIONS: We show that p53 loss influences the level of PD-L1 through IRF1 and SOX10 in an isogenic melanoma cell model, and that p53 loss affects NK-cell cytotoxicity toward tumor cells. Moreover, activation of p53 by MDM2 inhibition has a complex effect on IRF1/PD-L1 activation. These findings indicate that evaluation of p53 status in patients with melanoma will be important for predicting the response to PD-L1 monotherapy and/or dual treatments where p53 pathways participate in the overall response.

Aquaporin 1 is renoprotective in septic acute kidney injury by attenuating inflammation, apoptosis and fibrosis through inhibition of P53 expression.

Sepsis associated Acute kidney injury (AKI) is a common clinical syndrome characterized by suddenly decreased in renal function and urinary volume. This study was designed to investigate the role of Aquaporin 1 (AQP1) and P53 in the development of sepsis-induced AKI and their potential regulatory mechanisms. Firstly, transcriptome sequencing analysis of mice kidney showed AQP1 expression was reduced and P53 expression was elevated in Cecal ligation and puncture (CLP)-induced AKI compared with controls. Bioinformatics confirmed that AQP1 expression was remarkably decreased and P53 expression was obviously elevated in renal tissues or peripheral blood of septic AKI patients. Moreover, we found in vivo experiments that AQP1 mRNA levels were dramatically decreased and P53 mRNA significantly increased following the increased expression of inflammation, apoptosis, fibrosis, NGAL and KIM-1 at various periods in septic AKI. Meanwhile, AQP1 and P53 protein levels increased significantly first and then decreased gradually in kidney tissue and serum of rats in different stages of septic AKI. Most importantly, in vivo and vitro experiments demonstrated that silencing of AQP1 greatly exacerbates renal or cellular injury by up-regulating P53 expression promoting inflammatory response, apoptosis and fibrosis. Overexpression of AQP1 prevented the elevation of inflammation, apoptosis and fibrosis by down-regulating P53 expression in Lipopolysaccharide (LPS)-induced AKI or HK-2 cells. Therefore, our results suggested that AQP1 plays a protective role in modulating AKI and can attenuate inflammatory response, apoptosis and fibrosis via downregulating P53 in septic AKI or LPS-induced HK-2cells. The pharmacological targeting of AQP1 mediated P53 expression might be identified as potential targets for the early treatment of septic AKI.

TREM2 promotes the proliferation and invasion of renal cell carcinoma cells by inhibiting the P53 signaling pathway.

Renal cell carcinoma (RCC) is a prevalent malignancy characterized by poor prognosis and high mortality. The role of triggering receptor expressed on myeloid cells-2 (TREM2) in RCC progression has been increasingly recognized, yet its underlying mechanisms remain to be fully elucidated. The aim of the present study was to assess the effects of TREM2 on RCC cells and its potential mechanisms. Lentiviral transfection was used to knockdown and overexpress TREM2 in RCC cells, and the expression level of TREM2 was evaluated using reverse transcription-quantitative PCR. Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) assays were used to assess the proliferation of the RCC cells. Cell migration and invasion was evaluated using the wound healing assay and Transwell assay, respectively. Western blotting was used to assess the expression levels of TREM2, P53, p-P53, P21 and p-P21 in TREM2 knockdown or overexpression RCC cells. The results demonstrated that the expression level of TREM2 was significantly higher in cancer tissues compared with adjacent normal tissues. The results of the CCK-8 and EdU assays demonstrated that knockdown of TREM2 significantly inhibited the proliferation of RCC cells, whilst overexpression of TREM2 enhanced the proliferation of RCC cells. The results of the wound healing and Transwell assay revealed that, compared with the control group, the overexpression of TREM2 significantly increased the migration and invasion of RCC cells, whereas knockdown of TREM2 significantly decreased the migration of RCC cells. In addition, western blotting demonstrated that the phosphorylation levels of P53 and P21 proteins were significantly increased after TREM2 knockdown in RCC cells. In conclusion, TREM2 is highly expressed in RCC tissues and promotes the migration of RCC cells by inhibiting the P53 signaling pathway. The present study provides new insights into the regulatory effect of TREM2 on RCC and further reveals the potential of TREM2 as a therapeutic target for RCC.

LncRNA-HMG incites colorectal cancer cells to chemoresistance via repressing p53-mediated ferroptosis.

Upon chemotherapy, excessive reactive oxygen species (ROS) often lead to the production of massive lipid peroxides in cancer cells and induce cell death, namely ferroptosis. The elimination of ROS is pivotal for tumor cells to escape from ferroptosis and acquire drug resistance. Nevertheless, the precise functions of long non-coding RNAs (lncRNAs) in ROS metabolism and tumor drug-resistance remain elusive. In this study, we identify LncRNA-HMG as a chemoresistance-related lncRNA in colorectal cancer (CRC) by high-throughput screening. Abnormally high expression of LncRNA-HMG predicts poorer prognosis in CRC patients. Concurrently, we found that LncRNA-HMG protects CRC cells from ferroptosis upon chemotherapy, thus enhancing drug resistance of CRC cells. LncRNA-HMG binds to p53 and facilitates MDM2-mediated degradation of p53. Decreased p53 induces upregulation of SLC7A11 and VKORC1L1, which contribute to increase the supply of reducing agents and eliminate excessive ROS. Consequently, CRC cells escape from ferroptosis and acquire chemoresistance. Importantly, inhibition of LncRNA-HMG by anti-sense oligo (ASO) dramatically sensitizes CRC cells to chemotherapy in patient-derived xenograft (PDX) model. LncRNA-HMG is also a transcriptional target of ß-catenin/TCF and activated Wnt signals trigger the marked upregulation of LncRNA-HMG. Collectively, these findings demonstrate that LncRNA-HMG promotes CRC chemoresistance and might be a prognostic or therapeutic target for CRC.

IFN-γ induces acute graft-versus-host disease by promoting HMGB1-mediated nuclear-to-cytoplasm translocation and autophagic degradation of p53.

Acute graft-versus-host disease (aGVHD) poses a significant impediment to achieving a more favourable therapeutic outcome in allogeneic hematopoietic stem cell transplantation (allo-HSCT). Our prior investigations disclosed a correlation between p53 downregulation in CD4+ T cells and the occurrence of aGVHD. Notably, the insufficiency of the CCCTC-binding factor (CTCF) emerged as a pivotal factor in repressing p53 expression. However, the existence of additional mechanisms contributing to the reduction in p53 expression remains unclear. Interferon (IFN)-γ, a pivotal proinflammatory cytokine, assumes a crucial role in regulating alloreactive T cell responses and plays a complex part in aGVHD development. IFN-γ has the capacity to induce autophagy, a vital catabolic process facilitating protein degradation, in various cell types. Presently, whether IFN-γ participates in the development of aGVHD by instigating the autophagic degradation of p53 in CD4+ T cells remains an unresolved question. In this study, we demonstrated that heightened levels of IFN-γ in the plasma during aGVHD promoted the activation, proliferation, and autophagic activity of CD4+ T cells. Furthermore, IFN-γ induced the nuclear-to-cytoplasm translocation and autophagy-dependent degradation of p53 in CD4+ T cells. The translocation and autophagic degradation of p53 were contingent upon HMGB1, which underwent upregulation and translocation from the nucleus to the cytoplasm following IFN-γ stimulation. In conclusion, our data unveil a novel mechanism underlying p53 deficiency in CD4+ T cells among aGVHD patients. This deficiency is induced by IFN-γ and relies on autophagy, establishing a link between IFN-γ, HMGB1-mediated translocation, and the autophagic degradation of p53.

Targeting cellular plasticity: esculetin-driven reversion of stem cell-like characteristics and EMT phenotype in transforming cells with sequential p53/p73 knockdowns.

The intricate interplay of cancer stem cell plasticity, along with the bidirectional transformation between epithelial-mesenchymal states, introduces further intricacy to offer insights into newer therapeutic approaches. Differentiation therapy, while successful in targeting leukemic stem cells, has shown limited overall success, with only a few promising instances. Using colon carcinoma cell strains with sequential p53/p73 knockdowns, our study underscores the association between p53/p73 and the maintenance of cellular plasticity. Morphological alterations corresponding with cell surface marker expressions, transcriptome analysis and functional assays were performed to access stemness and EMT (Epithelial-Mesenchymal Transition) characteristics in the spectrum of cells exhibiting sequential p53 and p73 knockdowns. Notably, our investigation explores the effectiveness of esculetin in reversing the shift from an epithelial to a mesenchymal phenotype, characterized by stem cell-like traits. Esculetin significantly induces enterocyte differentiation and promotes epithelial cell polarity by altering Wnt axes in Cancer Stem Cell-like cells characterized by high mesenchymal features. These results align with our previous findings in leukemic blast cells, establishing esculetin as an effective differentiating agent in both Acute Myeloid Leukemia (AML) and solid tumor cells.