Cloning and expression of the rat p8 cDNA, a new gene activated in pancreas during the acute phase of pancreatitis, pancreatic development, and regeneration, and which promotes cellular growth

ATF4 in cellular stress, ferroptosis, and cancer

Activating transcription factor 4 (ATF4), a member of the ATF/cAMP response element-binding (CREB) family, plays a critical role as a stress-induced transcription factor. It orchestrates cellular responses, particularly in the management of endoplasmic reticulum stress, amino acid deprivation, and oxidative challenges. ATF4's primary function lies in regulating gene expression to ensure cell survival during stressful conditions. However, when considering its involvement in ferroptosis, characterized by severe lipid peroxidation and pronounced endoplasmic reticulum stress, the ATF4 pathway can either inhibit or promote ferroptosis. This intricate relationship underscores the complexity of cellular responses to varying stress levels. Understanding the connections between ATF4, ferroptosis, and endoplasmic reticulum stress holds promise for innovative cancer therapies, especially in addressing apoptosis-resistant cells. In this review, we provide an overview of ATF4, including its structure, modifications, and functions, and delve into its dual role in both ferroptosis and cancer.

Senescence program and its reprogramming in pancreatic premalignancy

Tumor is a representative of cell immortalization, while senescence irreversibly arrests cell proliferation. Although tumorigenesis and senescence seem contrary to each other, they have similar mechanisms in many aspects. Pancreatic ductal adenocarcinoma (PDA) is highly lethal disease, which occurs and progresses through a multi-step process. Senescence is prevalent in pancreatic premalignancy, as manifested by decreased cell proliferation and increased clearance of pre-malignant cells by immune system. However, the senescent microenvironment cooperates with multiple factors and significantly contributes to tumorigenesis. Evidently, PDA progression requires to evade the effects of cellular senescence. This review will focus on dual roles that senescence plays in PDA development and progression, the signaling effectors that critically regulate senescence in PDA, the identification and reactivation of molecular targets that control senescence program for the treatment of PDA.

Anti-HERV-K Drugs and Vaccines, Possible Therapies against Tumors

The footprint of human endogenous retroviruses (HERV), specifically HERV-K, has been found in malignancies, such as melanoma, teratocarcinoma, osteosarcoma, breast cancer, lymphoma, and ovary and prostate cancers. HERV-K is characterized as the most biologically active HERV due to possession of open reading frames (ORF) for all Gag, Pol, and Env genes, which enables it to be more infective and obstructive towards specific cell lines and other exogenous viruses, respectively. Some factors might contribute to carcinogenicity and at least one of them has been recognized in various tumors, including overexpression/methylation of long interspersed nuclear element 1 (LINE-1), HERV-K Gag, and Env genes themselves plus their transcripts and protein products, and HERV-K reverse transcriptase (RT). Therapies effective for HERV-K-associated tumors mostly target invasive autoimmune responses or growth of tumors through suppression of HERV-K Gag or Env protein and RT. To design new therapeutic options, more studies are needed to better understand whether HERV-K and its products (Gag/Env transcripts and HERV-K proteins/RT) are the initiators of tumor formation or just the disorder’s developers. Accordingly, this review aims to present evidence that highlights the association between HERV-K and tumorigenicity and introduces some of the available or potential therapies against HERV-K-induced tumors.

Nupr1 deficiency downregulates HtrA1, enhances SMAD1 signaling, and suppresses age-related bone loss in male mice

Nuclear protein 1 (NUPR1) is a stress-induced protein activated by various stresses, such as inflammation and oxidative stress. We previously reported that Nupr1 deficiency increased bone volume by enhancing bone formation in 11-week-old mice. Analysis of differentially expressed genes between wild-type (WT) and Nupr1-knockout (Nupr1-KO) osteocytes revealed that high temperature requirement A 1 (HTRA1), a serine protease implicated in osteogenesis and transforming growth factor-β signaling was markedly downregulated in Nupr1-KO osteocytes. Nupr1 deficiency also markedly reduced HtrA1 expression, but enhanced SMAD1 signaling in in vitro-cultured primary osteoblasts. In contrast, Nupr1 overexpression enhanced HtrA1 expression in osteoblasts, suggesting that Nupr1 regulates HtrA1 expression, thereby suppressing osteoblastogenesis. Since HtrA1 is also involved in cellular senescence and age-related diseases, we analyzed aging-related bone loss in Nupr1-KO mice. Significant spine trabecular bone loss was noted in WT male and female mice during 6-19 months of age, whereas aging-related trabecular bone loss was attenuated, especially in Nupr1-KO male mice. Moreover, cellular senescence-related markers were upregulated in the osteocytes of 6-19-month-old WT male mice but markedly downregulated in the osteocytes of 19-month-old Nupr1-KO male mice. Oxidative stress-induced cellular senescence stimulated Nupr1 and HtrA1 expression in in vitro-cultured primary osteoblasts, and Nupr1 overexpression enhanced p16^ink4a expression in osteoblasts. Finally, NUPR1 expression in osteocytes isolated from the bones of patients with osteoarthritis was correlated with age. Collectively, these results indicate that Nupr1 regulates HtrA1-mediated osteoblast differentiation and senescence. Our findings unveil a novel Nupr1/HtrA1 axis, which may play pivotal roles in bone formation and age-related bone loss.

Intrinsically Disordered Chromatin Protein NUPR1 Binds to the Enzyme PADI4

The nuclear protein 1 (NUPR1) is an intrinsically disordered protein involved in stress-mediated cellular conditions. Its paralogue nuclear protein 1-like (NUPR1L) is p53-regulated, and its expression down-regulates that of the NUPR1 gene. Peptidyl-arginine deiminase 4 (PADI4) is an isoform of a family of enzymes catalyzing arginine to citrulline conversion; it is also involved in stress-mediated cellular conditions. We characterized the interaction between NUPR1 and PADI4 in vitro, in silico, and in cellulo. The interaction of NUPR1 and PADI4 occurred with a dissociation constant of 18 ± 6 μM. The binding region of NUPR1, mapped by NMR, was a hydrophobic polypeptide patch surrounding the key residue Ala33, as pinpointed by: (i) computational results; and, (ii) site-directed mutagenesis of residues of NUPR1. The association between PADI4 and wild-type NUPR1 was also assessed in cellulo by using proximity ligation assays (PLAs) and immunofluorescence (IF), and it occurred mainly in the nucleus. Moreover, binding between NUPR1L and PADI4 also occurred in vitro with an affinity similar to that of NUPR1. Molecular modelling provided information on the binding hot spot for PADI4. This is an example of a disordered partner of PADI4, whereas its other known interacting proteins are well-folded. Altogether, our results suggest that the NUPR1/PADI4 complex could have crucial functions in modulating DNA-repair, favoring metastasis, or facilitating citrullination of other proteins.

Nuclear Protein 1 Expression Is Associated with PPARG in Bladder Transitional Cell Carcinoma

Background

The Nuclear protein 1 gene was first discovered in acute pancreatitis and functions as an oncogene in cancer progression and drug resistance. However, the role of Nuclear protein 1 in bladder transitional cell carcinoma (BTCC) is still unclear.

Methods

The Cancer Genome Atlas database and immunohistochemical analysis were adopted to evaluate Nuclear protein 1 expression in BTCC. We applied lentivirus-mediated small-interfering RNA to down-regulate the expression of Nuclear protein 1 in BTCC cell lines. We further performed an Affymetrix microarray and Gene Set Enrichment Analysis (GSEA) to assess the genes and signaling pathways related to Nuclear protein 1.

Results

We found that Nuclear protein 1 expression was up-regulated in BTCC and positively related to the degree of BTCC malignancy. Compared with Caucasian patients with BTCC, Nuclear protein 1 expression was attenuated in Asian patients. The Affymetrix microarray showed that lipopolysaccharide was the upstream regulatory factor of Nuclear protein 1 in BTCC. The GSEA indicated that Nuclear protein 1 expression was associated with signaling pathways in cancer, peroxisome proliferator-activated receptor (PPAR) pathways, and RNA degradation. The expression of Nuclear protein 1 was negatively correlated with PPARG (R = -0.290, P < 0.001), but not with PPARA (R = 0.047, P = 0.344) and PPARD (R = -0.055, P = 0.260).

Conclusions

The study findings indicate that Nuclear protein 1 is positively associated with the malignancy degree of BTCC and that Nuclear protein 1 expression is negatively correlated with PPARG.

NUPR1 imparts oncogenic potential in bladder cancer

BACKGROUND

NUPR1, or p8, is a small chromatin protein that plays a central role in the resistance to treatment and progression of cancer. Nevertheless, the molecular mechanism of NUPR1 in bladder cancer (BLCA) remains unclear.

METHODS

We used online databases and immunohistochemistry (IHC) to explore the expression of NUPR1 in BLCA tissues and controls. Lentivirus-mediated small interfering ribonucleic acid (siRNA) was used to knockdown the expression of NUPR1 in two human BLCA cell lines. We used an in vivo experiment to investigate the effect of NUPR1 knockdown on the growth of BLCA. Moreover, an in silico analysis was conducted to assess the differential expression profile after NUPR1 interference. The CIBERSORT algorithm was utilized to evaluate the effects of tumor-infiltrating immune cells among BLCA patients.

RESULTS

The expression of NUPR1 in BLCA tissues was significantly higher than in the control. NUPR1 expression was also positively correlated with the stage of BLCA. After lentivirus-mediated interference, the expression of NUPR1 was significantly down-regulated in BLCA cell lines. The cell cycle was blocked in G1 phase and the cell proportion of S phase was decreased in both two cell lines. Moreover, in vivo experiment revealed that the tumor growth of BLCA can be delayed by inhibiting the expression of NUPR1. Both in silico analysis and functional experiments revealed that NUPR1 was correlated with epithelial-mesenchymal transition (EMT). We also revealed that macrophages were the most related immune cells associated with the expression of NUPR1 in BLCA.

CONCLUSIONS

This study suggests that NUPR1 plays a carcinogenic role in BLCA. NUPR1 lentivirus-mediated interference could interfere with cycle progression of the BLCA cell, resulting in cell cycle arrest in the G1-phase. The carcinogenic effect of NUPR1 in BLCA is likely achieved through EMT. NUPR1 is correlated with the M0-type macrophage markers CD68 and CD11b-integrin.

The expression of apoptosis related genes in HK-2 cells overexpressing PPM1K was determined by RNA-seq analysis

Chronic kidney disease (CKD) is a serious disease that endangers human health. It is reported that inhibiting renal cell apoptosis can delay the progress of CKD. Our previous study found that the mice with protein phosphatase Mg2+/Mn2+ dependent 1K (PPM1K) gene deletion had obvious symptoms of glomerular vascular and interstitial vascular dilatation, congestion and hemorrhage, glomerular hemorrhage and necrosis, interstitial fibrous tissue proliferation, decreased urinary creatinine clearance, and increased urinary protein level. In addition, studies have found that PPM1K is essential for cell survival, apoptosis and metabolism. However, no study has confirmed that PPM1K can inhibit renal cell apoptosis. In this study, PPM1K was overexpressed in human kidney-2 cells (HK-2), and the biological process of differentially expressed genes and its effect on apoptosis were comprehensively screened by RNA sequencing (RNA-seq). Through sequencing analysis, we found that there were 796 differentially expressed genes in human renal tubular epithelial cells transfected with PPM1K gene, of which 553 were down-regulated and 243 were up-regulated. Enrichment analysis found that differentially expressed genes may play an important role in amino acid metabolism and biosynthesis. In the GO analysis functional pathway list, we also found that multiple genes can be enriched in apoptosis related pathways, such as G0S2, GADD45A, TRIB3, VEGFA, NUPR1 and other up-regulated genes, and IL-6, MAGED1, CCL2, TP53INP1 and other down-regulated genes. Then we verified these differentially expressed genes by RT-PCR, and found that only the RT-PCR results of G0S2, VEGFA and NUPR1 were consistent with the transcriptome sequencing results. We believe that G0S2, VEGFA, NUPR1 and other genes may participate in the apoptosis process of HK-2 cells induced by PPM1K.In conclusion, these findings provide some data support for the study of HK-2 cell apoptosis mechanism, and also provide a scientific theoretical basis for further study of the effect of PPM1K on kidney disease.

The role of NUPR1 in response to stress and cancer development

Stress contributes to the development of many human diseases, including cancer. Based on the source of stress, it can be divided into external stress, such as environmental carcinogens, chemicals, and radiation, and internal stress, like endoplasmic reticulum (ER) stress, hypoxia, and oxidative stress. Nuclear Protein 1 (NUPR1, p8 or Com-1) is a small, highly basic transcriptional regulator that participates in regulating a variety of cellular processes including DNA repair, ER stress, oxidative stress response, cell cycle, autophagy, apoptosis, ferroptosis and chromatin remodeling. A large number of studies have reported that NUPR1 expression can be stimulated rapidly in response to various stresses. Thus, NUPR1 is also known as a stress-response gene. Since the role of NUPR1 in breast cancer was identified in 1999, an increasing number of studies sought to reveal its function in cancer. High expression of NUPR1 has been identified in oral squamous cell carcinoma, breast cancer, lung cancer, multiple myeloma, liver cancer and renal cancer. In this review, we summarize current studies of NUPR1 in response to multiple external stressors and internal stressors, and its role in mediating stressors to cause different cell signaling responses. In addition, this review discusses the function of NUPR1 in carcinogenesis, tumorigenesis, metastasis, and cancer therapy. Thus, this review gives a comprehensive insight into the role of NUPR1 in mediating signals from stress to different cell responses, and this process plays a role in the development of cancer.

Transcription factor p8 regulates autophagy in response to disulfiram via PI3K/mTOR/p70S6K signaling pathway in pancreatic cancer cells

Disulfiram (DSF), which is an inhibitor of aldehyde dehydrogenase (ALDH) and approved by the FDA for the treatment of alcoholism previously, has been repurposed for use as a cancer treatment because of its potent effect in preclinical studies. In this study, we found that disulfiram forms potent complexes with copper (DSF/Cu) inhibited cell proliferation, induced apoptosis in human pancreatic cancer cells, which was detected by flow cytometry and western blotting. Meanwhile, autophagy and autophagic flux also clearly observed by transmission electron microscopy, confocal microscopy and flow cytometry. Our results also showed that DSF/Cu induced transcription factor p8 upregulation and PI3K/mTOR signaling pathway activation detected by real-time PCR and western blotting. Additionally, suppression of p8 inactivated the mTOR signaling pathway and autophagic flux maintained. Furthermore, mechanism study indicated that autophagy induced by DSF/Cu was regulated by p8 and was related to PI3K/mTOR/p70S6K signaling pathway in pancreatic cancer cells. Our findings provide insights into the role of p8 in regulating autophagy induced by DSF/Cu effects in pancreatic cancer cells.

NUPR1 protects against hyperPARylation-dependent cell death

Proteomic, cellular and biochemical analysis of the stress protein NUPR1 reveals that it binds to PARP1 into the nucleus and inhibits PARP1 activity in vitro. Mutations on residues Ala33 or Thr68 of NUPR1 or treatment with its inhibitor ZZW-115 inhibits this effect. PARylation induced by 5-fluorouracil (5-FU) treatment is strongly enhanced by ZZW-115 and associated with a decrease of NAD⁺/NADH ratio and rescued by the PARP inhibitor olaparib. Cell death induced by ZZW-115 treatment of pancreas cancer-derived cells is rescued by olaparib and improved with PARG inhibitor PDD00017273. The mitochondrial catastrophe induced by ZZW-115 treatment or by genetic inactivation of NUPR1 is associated to a hyperPARylation of the mitochondria, disorganization of the mitochondrial network, mitochondrial membrane potential decrease, and with increase of superoxide production, intracellular level of reactive oxygen species (ROS) and cytosolic levels of Ca²⁺. These features are rescued by olaparib or NAD⁺ precursor nicotinamide mononucleotide in a dose-dependent manner and partially by antioxidants treatments. In conclusion, inactivation of NUPR1 induces a hyperPARylation, which in turn, induces a mitochondrial catastrophe and consequently a cell death through a non-canonical Parthanatos, since apoptosis inducing-factor (AIF) is not translocated out of the mitochondria.

Thermal stress induces expression of Nuclear protein and Parkin genes in endangered catfish, Clarias magur

Fluctuation in water temperature can create thermal stress, which may impact many aspects of fish life, such as survival, growth, reproduction, disease occurrence etc. The endangered catfish, Clarias magur, has been reported to survive at higher thermal stress, even though the exact mechanism is unknown. The genes coding for Nuclear protein 1 (Nupr1) and Parkin E3 ubiquitin protein ligase (Park2) have been reported to protect cells from stress-induced damage and death. In this study, we characterized both the genes and assessed their quantitative expression in C. magur. Structural features of both the genes were found similar to a related catfish, Ictalurus punctatus, and model fish zebrafish. The genes were fairly conserved in fishes as observed through phylogenetic analysis. The real time expression of the two stress-associated genes were also assessed in brain, kidney, liver and muscle tissues of C. magur exposed to warm (34 °C) and cold (15 °C) water. RT-PCR analysis revealed up-regulation in the relative expression levels of Nupr1 and Park2 genes at both temperatures with maximum positive fold change during stress to cold water, even though the posteriori Dunnett's test after ANOVA revealed that there were significant differences between the control and challenged groups. The study indicated that Nupr1 gene plays role in muscle tissue at both high and low thermal stress, but at high thermal stress in liver, while Park2 plays role in muscle, brain and kidney at low temperature and in liver at high temperature stress in C. magur. The study has generated first-hand information under warm- and cold water, which pave the way to understand the expression response of these genes to thermal vacillations and to establish evolutionary significance in catfishes and other species.

Upregulation of COPB2 Promotes Prostate Cancer Proliferation and Invasion Through the MAPK/TGF-β Signaling Pathway

There is increasing evidence that coatomer protein complex subunit beta 2 (COPB2) plays an important role in various cancer types. This study explored the role and the downstream mediators of COPB2 in prostate cancer (PCa). The expression of COPB2 was determined by the Cancer Genome Atlas database and enzyme-linked immunosorbent assay. COPB2 expression was upregulated in PCa tissues and correlated with Gleason score, biochemical recurrence, and poor prognosis. The functional roles of COPB2 in PCa were verified through a series of experiments. Knocking down COPB2 expression inhibited the growth and clonogenesis of PCa cells, promoted cell apoptosis, and inhibited the ability of scratch repair, invasion of PCa cells, and tumor growth in Nude mice. To analyze downstream signaling pathways, ingenuity pathway analysis, GSEA, and whole-genome expression spectrum GeneChip analysis were used. Western blot revealed that COPB2 expression promoted the proliferation and invasion of PCa cells by regulating the MAPK/TGF-β signaling pathway. The interacting protein (nuclear protein 1, NUPR1) was identified via Co-IP, real-time PCR, Western blot, and TCGA database in sampled tissues. The expressions of the interaction proteins NUPR1 and COPB2 were negatively regulated by each other. COPB2 could be a new biomarker for PCa diagnosis and monitoring and to provide a theoretical basis for identifying effective drug intervention targets through in-depth mechanistic studies.

Histone methyltransferase Dot1L inhibits pancreatic cancer cell apoptosis by promoting NUPR1 expression

Objective

To explore functions of the histone H3 lysine 79 (K79) methyltransferase Dot1L in the development of pancreatic cancer and evaluate the possibility of targeting Dot1L to inhibit pancreatic cancer progression.

Methods

Patient samples were used to detect differences in Dot1L expression between tumor and adjacent tissues and to determine correlations between Dot1L expression in patients with different stages of pancreatic cancer. Lentiviral-mediated knockdown of Dot1L expression and flow cytometry were used to detect apoptosis in pancreatic cancer lacking Dot1L expression; chromatin immunoprecipitation and quantitative PCR were used to detect downstream target genes of Dot1L.

Results

We show that Dot1L is highly expressed in pancreatic cancer, and that its expression is related to pancreatic cancer stage. Knocking down Dot1L significantly promoted apoptosis in pancreatic cancer cells, while overexpressing Dot1L inhibited apoptosis. Mechanistically, Dot1L regulated apoptosis in pancreatic cancer cells by promoting NUPR1 expression. The enriched H3K79 trimethylation in the transcription initiation region of NUPR1 promoted its expression. Overexpressing NUPR1 inhibited the pancreatic cancer cell apoptosis caused by Dot1L knockdown.

Conclusions

Dot1L inhibits pancreatic cancer cell apoptosis by targeting NUPR1; thus, Dot1L is a promising target for pancreatic cancer treatment.

Design of Inhibitors of the Intrinsically Disordered Protein NUPR1: Balance between Drug Affinity and Target Function

Intrinsically disordered proteins (IDPs) are emerging as attractive drug targets by virtue of their physiological ubiquity and their prevalence in various diseases, including cancer. NUPR1 is an IDP that localizes throughout the whole cell, and is involved in the development and progression of several tumors. We have previously repurposed trifluoperazine (TFP) as a drug targeting NUPR1 and, by using a ligand-based approach, designed the drug ZZW-115 starting from the TFP scaffold. Such derivative compound hinders the development of pancreatic ductal adenocarcinoma (PDAC) in mice, by hampering nuclear translocation of NUPR1. Aiming to further improve the activity of ZZW-115, here we have used an indirect drug design approach to modify its chemical features, by changing the substituent attached to the piperazine ring. As a result, we have synthesized a series of compounds based on the same chemical scaffold. Isothermal titration calorimetry (ITC) showed that, with the exception of the compound preserving the same chemical moiety at the end of the alkyl chain as ZZW-115, an increase of the length by a single methylene group (i.e., ethyl to propyl) significantly decreased the affinity towards NUPR1 measured in vitro, whereas maintaining the same length of the alkyl chain and adding heterocycles favored the binding affinity. However, small improvements of the compound affinity towards NUPR1, as measured by ITC, did not result in a corresponding improvement in their inhibitory properties and in cellulo functions, as proved by measuring three different biological effects: hindrance of the nuclear translocation of the protein, sensitization of cells against DNA damage mediated by NUPR1, and prevention of cancer cell growth. Our findings suggest that a delicate compromise between favoring ligand affinity and controlling protein function may be required to successfully design drugs against NUPR1, and likely other IDPs.

NUPR1 inhibitor ZZW-115 induces ferroptosis in a mitochondria-dependent manner

Ferroptosis is an iron-dependent cell death characterized by the accumulation of hydroperoxided phospholipids. Here, we report that the NUPR1 inhibitor ZZW-115 induces ROS accumulation followed by a ferroptotic cell death, which could be prevented by ferrostatin-1 (Fer-1) and ROS-scavenging agents. The ferroptotic activity can be improved by inhibiting antioxidant factors in pancreatic ductal adenocarcinoma (PDAC)- and hepatocellular carcinoma (HCC)-derived cells. In addition, ZZW-115-treatment increases the accumulation of hydroperoxided lipids in these cells. We also found that a loss of activity and strong deregulation of key enzymes involved in the GSH- and GPX-dependent antioxidant systems upon ZZW-115 treatment. These results have been validated in xenografts induced with PDAC- and HCC-derived cells in nude mice during the treatment with ZZW-115. More importantly, we demonstrate that ZZW-115-induced mitochondrial morphological changes, compatible with the ferroptotic process, as well as mitochondrial network disorganization and strong mitochondrial metabolic dysfunction, which are rescued by both Fer-1 and N-acetylcysteine (NAC). Of note, the expression of TFAM, a key regulator of mitochondrial biogenesis, is downregulated by ZZW-115. Forced expression of TFAM is able to rescue morphological and functional mitochondrial alterations, ROS production, and cell death induced by ZZW-115 or genetic inhibition of NUPR1. Altogether, these results demonstrate that the mitochondrial cell death mediated by NUPR1 inhibitor ZZW-115 is fully rescued by Fer-1 but also via TFAM complementation. In conclusion, TFAM could be considered as an antagonist of the ferroptotic cell death.

Nupr1 mediates renal fibrosis via activating fibroblast and promoting epithelial-mesenchymal transition

Renal interstitial fibrosis (RIF) is a pathological process that fibrotic components are excessively deposited in the renal interstitial space due to kidney injury, resulting in impaired renal function and chronic kidney disease. The molecular mechanisms controlling renal fibrosis are not fully understood. In this present study, we identified Nuclear protein 1 (Nupr1), a transcription factor also called p8, as a novel regulator promoting renal fibrosis. Unilateral ureteral obstruction (UUO) time-dependently induced Nupr1 mRNA and protein expression in mouse kidneys while causing renal damage and fibrosis. Nupr1 deficiency (Nupr1^-/- ) attenuated the renal tubule dilatation, tubular epithelial cell atrophy, and interstitial collagen accumulation caused by UUO. Consistently, Nupr1^-/- significantly decreased the expression of type I collagen, myofibroblast markers smooth muscle α-actin (α-SMA), fibroblast-specific protein 1 (FSP-1), and vimentin in mouse kidney that were upregulated by UUO. These results suggest that Nupr1 protein was essential for fibroblast activation and/or epithelial-mesenchymal transition (EMT) during renal fibrogenesis. Indeed, Nupr1 was indispensable for TGF-β-induced myofibroblast activation of kidney interstitial NRK-49F fibroblasts, multipotent mesenchymal C3H10T1/2 cells, and the EMT of kidney epithelial NRK-52E cells. It appears that Nupr1 mediated TGF-β-induced α-SMA expression and collagen synthesis by initiating Smad3 signaling pathway. Importantly, trifluoperazine (TFP), a Nupr1 inhibitor, alleviated UUO-induced renal fibrosis. Taken together, our results demonstrate that Nupr1 promotes renal fibrosis by activating myofibroblast transformation from both fibroblasts and tubular epithelial cells.

Crowding Effects on the Structure and Dynamics of the Intrinsically Disordered Nuclear Chromatin Protein NUPR1

The intracellular environment is crowded with macromolecules, including sugars, proteins and nucleic acids. In the cytoplasm, crowding effects are capable of excluding up to 40% of the volume available to any macromolecule when compared to dilute conditions. NUPR1 is an intrinsically disordered protein (IDP) involved in cell-cycle regulation, stress-cell response, apoptosis processes, DNA binding and repair, chromatin remodeling and transcription. Simulations of molecular crowding predict that IDPs can adopt compact states, as well as more extended conformations under crowding conditions. In this work, we analyzed the conformation and dynamics of NUPR1 in the presence of two synthetic polymers, Ficoll-70 and Dextran-40, which mimic crowding effects in the cells, at two different concentrations (50 and 150 mg/ml). The study was carried out by using a multi-spectroscopic approach, including: site-directed spin labelling electron paramagnetic resonance spectroscopy (SDSL-EPR), nuclear magnetic resonance spectroscopy (NMR), circular dichroism (CD), small angle X-ray scattering (SAXS) and dynamic light scattering (DLS). SDSL-EPR spectra of two spin-labelled mutants indicate that there was binding with the crowders and that the local dynamics of the C and N termini of NUPR1 were partially affected by the crowders. However, the overall disordered nature of NUPR1 did not change substantially in the presence of the crowders, as shown by circular dichroism CD and NMR, and further confirmed by EPR. The changes in the dynamics of the paramagnetic probes appear to be related to preferred local conformations and thus crowding agents partially affect some specific regions, further pinpointing that NUPR1 flexibility has a key physiological role in its activity.

NUPR1 interacts with eIF2α and is required for resolution of the ER stress response in pancreatic tissue

Nuclear protein 1 (NUPR1) is a stress response protein overexpressed upon cell injury in virtually all organs including the exocrine pancreas. Despite NUPR1's well-established role in the response to cell stress, the molecular and structural machineries triggered by NUPR1 activation remain largely debated. In this study, we uncover a new role for NUPR1, participating in the unfolded protein response (UPR) and the integrated stress response. Biochemical results and ultrastructural morphological observations revealed alterations in the UPR of acinar cells of germline-deleted NUPR1 murine models, consistent with the inability to restore general protein synthesis after stress induction. Bioinformatic analysis of NUPR1-interacting partners showed significant enrichment in translation initiation factors, including eukaryotic initiation factor (eIF) 2α. Co-immunoprecipitation and proximity ligation assays confirmed the interaction between NUPR1 and eIF2α and its phosphorylated form (p-eIF2α). Furthermore, our data suggest loss of NUPR1 in cells results in maintained eIF2α phosphorylation and evaluation of nascent proteins by click chemistry revealed that NUPR1-depleted PANC-1 cells displayed a slower poststress protein synthesis recovery when compared to wild-type. Combined, these data propose a novel role for NUPR1 in the integrated stress response pathway, at least partially through promoting efficient PERK branch activity and resolution through a unique interaction with eIF2α.

NUPR1 is a novel potential biomarker and confers resistance to sorafenib in clear cell renal cell carcinoma by increasing stemness and targeting the PTEN/AKT/mTOR pathway

BACKGROUND

Sorafenib can improve the survival of metastatic clear cell renal cell carcinoma (ccRCC) patients. However, its benefits are modest, as patients eventually become resistant, and the mechanisms remain elusive. NUPR1, a stress-induced protein, has been reported in malignancies and functions as an oncogene by modulating the stress response, facilitating survival in harsh environments and conferring drug resistance. However, its role in ccRCC has not been explored.

METHODS

The expression and clinical significance of NUPR1 were analyzed in ccRCC patients in in-house patients and The Cancer Genome Atlas (TCGA) cohorts. The biological functions of NUPR1 were investigated. Xenografts were performed to confirm the effects of NUPR1 on tumorigenesis. The molecular mechanism of NUPR1 was investigated in vitro and in vivo.

RESULTS

NUPR1 expression was upregulated in tumor tissue. Further analysis showed that NUPR1 overexpression was associated with an aggressive phenotype and predicted a poor prognosis. Depletion of NUPR1 suppressed tumorigenesis and sensitized cells to sorafenib treatment. Finally, mechanistic investigations indicated that NUPR1 promoted tumorigenesis in ccRCC by increasing stemness and activating the PTEN/AKT/mTOR signaling pathway.

CONCLUSIONS

Collectively, our results suggest that NUPR1 may serve as a predictor of ccRCC. Notably, NUPR1 silencing reversed sorafenib resistance in ccRCC. These findings provide a novel potential therapeutic target in the clinical management of ccRCC.

Targeting Fibrosis: The Bridge That Connects Pancreatitis and Pancreatic Cancer

Pancreatic fibrosis is caused by the excessive deposits of extracellular matrix (ECM) and collagen fibers during repeated necrosis to repair damaged pancreatic tissue. Pancreatic fibrosis is frequently present in chronic pancreatitis (CP) and pancreatic cancer (PC). Clinically, pancreatic fibrosis is a pathological feature of pancreatitis and pancreatic cancer. However, many new studies have found that pancreatic fibrosis is involved in the transformation from pancreatitis to pancreatic cancer. Thus, the role of fibrosis in the crosstalk between pancreatitis and pancreatic cancer is critical and still elusive; therefore, it deserves more attention. Here, we review the development of pancreatic fibrosis in inflammation and cancer, and we discuss the therapeutic strategies for alleviating pancreatic fibrosis. We further propose that cellular stress response might be a key driver that links fibrosis to cancer initiation and progression. Therefore, targeting stress proteins, such as nuclear protein 1 (NUPR1), could be an interesting strategy for pancreatic fibrosis and PC treatment.

CircRNA HIPK3 promotes the progression of oral squamous cell carcinoma through upregulation of the NUPR1/PI3K/AKT pathway by sponging miR-637

Background

To investigate the expression, function, and related mechanisms of circHIPK3 in oral squamous cell carcinoma (OSCC).

Methods

CircHIPK3 expression was determined by quantitative reverse transcription polymerized chain reaction (QRT-PCR) in OSCC and adjacent tissues, and the correlation between the circHIPK3 level and clinicopathological indexes of OSCC was analyzed. CircHIPK3 expressions in different OSCC cell lines were detected, cell counting kit-8 (CCK-8) and 5-bromodeoxyuridine (BrdU) assays were utilized to monitor cell proliferation and activity. Flow cytometry was adopted to detect apoptosis and transwell assay was used to detect cell invasion. The expressions of nuclear protein 1 (NUPR1), phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT) (PI3K/AKT) pathway proteins, and E-cadherin, Vimentin, and N-cadherin markers of epithelial-mesenchymal transformation (EMT) were detected by Western blot or Quantitative Real-time PCR (QRT-PCR).

Results

Upregulated circHIPK3 was noted in OSCC tissues (compared with adjacent tissues), and its overexpression was related to OSCC size and histopathological grade. Functionally, overexpressed circHIPK3 can significantly promote EMT, proliferation, and invasion of OSCC cells and can inhibit cell apoptosis in vivo and in vitro. In addition, CircHIPK3 upregulated the activation of NUPR1 and PI3K/AKT. Bioinformatics analyses showed that miR-637 was the common target of circHIPK3 and NUPR1, while a dual luciferase reporting assay and RIP assay further demonstrated that circHIPK3 targeted miR-637 and bound to 3' UTR of NUPR1.

Conclusions

CircHIPK3 demonstrates potential as a prognostic marker of OSCC and mediates OSCC progression via the miR-637-mediated NUPR1/PI3K/AKT axis.

Human Endogenous Retrovirus (HERV)-K env Gene Knockout Affects Tumorigenic Characteristics of nupr1 Gene in DLD-1 Colorectal Cancer Cells

Human endogenous retroviruses (HERVs) are suggested to be involved in the development of certain diseases, especially cancers. To elucidate the function of HERV-K Env protein in cancers, an HERV-K env gene knockout (KO) in DLD-1 colorectal cancer cell lines was generated using the CRISPR-Cas9 system. Transcriptome analysis of HERV-K env KO cells using next-generation sequencing (NGS) was performed to identify the key genes associated with the function of HERV-K Env protein. The proliferation of HERV-K env KO cells was significantly reduced in in vitro culture as well as in in vivo nude mouse model. Tumorigenic characteristics, including migration, invasion, and tumor colonization, were also significantly reduced in HERV-K env KO cells. Whereas, they were enhanced in HERV-K env over-expressing DLD-1 cells. The expression of nuclear protein-1 (NUPR1), an ER-stress response factor that plays an important role in cell proliferation, migration, and reactive oxygen species (ROS) generation in cancer cells, significantly reduced in HERV-K env KO cells. ROS levels and ROS-related gene expression was also significantly reduced in HERV-K env KO cells. Cells transfected with NUPR1 siRNA (small interfering RNA) exhibited the same phenotype as HERV-K env KO cells. These results suggest that the HERV-K env gene affects tumorigenic characteristics, including cell proliferation, migration, and tumor colonization through NUPR1 related pathway.

Inhibition of NUPR1-Karyopherin β1 Binding Increases Anticancer Drug Sensitivity

Background: Nuclear protein-1 (NUPR1, also known as p8/Com-1) is a transcription factor involved in the regulation of cellular stress responses, including serum starvation and drug stimulation. Methods: We investigated the mechanism of NUPR1 nuclear translocation involving karyopherin β1 (KPNB1), using a single-molecule binding assay and confocal microscopy. The cellular effects associated with NUPR1–KPNB1 inhibition were investigated by gene expression profiling and cell cycle analysis. Results: The single-molecule binding assay revealed that KPNB1 bound to NUPR1 with a binding affinity of 0.75 nM and that this binding was blocked by the aminothiazole ATZ-502. Following doxorubicin-only treatment, NUPR1 was translocated to the nucleus in more than 90% and NUPR1 translocation was blocked by the ATZ-502 combination treatment in MDA-MB-231 with no change in NUPR1 expression, providing strong evidence that NUPR1 nuclear translocation was directly inhibited by the ATZ-502 treatment. Inhibition of KPNB1 and NUPR1 binding was associated with a synergistic anticancer effect (up to 19.6-fold) in various cancer cell lines. NUPR1-related genes were also downregulated following the doxorubicin–ATZ-502 combination treatment. Conclusion: Our current findings clearly demonstrate that NUPR1 translocation into the nucleus requires karyopherin β1 binding. Inhibition of the KPNB1 and NUPR1 interaction may constitute a new cancer therapeutic approach that can increase the drug efficacy while reducing the side effects.

Induction of NUPR1 and AP‑1 contributes to the carcinogenic potential of nickel

Nickel (Ni) is carcinogenic to humans, and causes cancers of the lung, nasal cavity, and paranasal sinuses. The primary mechanisms of Ni‑mediated carcinogenesis involve the epigenetic reprogramming of cells and the ability for Ni to mimic hypoxia. However, the exact mechanisms of carcinogenesis related to Ni are obscure. Nuclear protein 1 (NUPR1) is a stress‑response gene overexpressed in cancers, and is capable of conferring chemotherapeutic resistance. Likewise, activator protein 1 (AP‑1) is highly responsive to environmental signals, and has been associated with cancer development. In this study, NUPR1 was found to be rapidly and highly induced in human bronchial epithelial (BEAS‑2B) cells exposed to Ni, and was overexpressed in Ni‑transformed BEAS‑2B cells. Similarly, AP‑1 subunits, JUN and FOS, were induced in BEAS‑2B cells following Ni exposure. Knockdown of JUN or FOS was found to significantly suppress NUPR1 induction following Ni exposure, demonstrating their importance in NUPR1 transactivation. Reactive oxygen species (ROS) are known to induce AP‑1, and Ni has been shown to produce ROS. Treatment of BEAS‑2B cells with antioxidants was unable to prevent NUPR1 induction by Ni, suggesting that NUPR1 induction by Ni relies on mechanisms other than oxidative stress. To determine how NUPR1 is transcriptionally regulated following Ni exposure, the NUPR1 promoter was cloned and inserted into a luciferase gene reporter vector. Multiple JUN binding sites reside within the NUPR1 promoter, and upon deleting a JUN binding site in the upstream most region within the NUPR1 promoter using site‑directed mutagenesis, NUPR1 promoter activity was significantly reduced. This suggests that AP‑1 transcriptionally regulates NUPR1. Moreover, knockdown of NUPR1 significantly reduced colony formation and anchorage‑independent growth in Ni‑transformed BEAS‑2B cells. Therefore, these results collectively demonstrate a novel mechanism of NUPR1 induction following Ni exposure, and provide a molecular basis by which NUPR1 may contribute to lung carcinogenesis.

NUPR1 protects liver from lipotoxic injury by improving the endoplasmic reticulum stress response

Non-alcoholic fatty liver (NAFL) and related syndromes affect one-third of the adult population in industrialized and developing countries. Lifestyle and caloric oversupply are the main causes of such array of disorders, but the molecular mechanisms underlying their etiology remain elusive. Nuclear Protein 1 (NUPR1) expression increases upon cell injury in all organs including liver. Recently, we reported NUPR1 actively participates in the activation of the Unfolded Protein Response (UPR). The UPR typically maintains protein homeostasis, but downstream mediators of the pathway regulate metabolic functions including lipid metabolism. As increases in UPR and NUPR1 in obesity and liver disease have been well documented, the goal of this study was to investigate the roles of NUPR1 in this context. To establish whether NUPR1 is involved in these liver conditions we used patient-derived liver biopsies and in vitro and in vivo NUPR1 loss of functions models. First, we analyzed NUPR1 expression in a cohort of morbidly obese patients (MOPs), with simple fatty liver (NAFL) or more severe steatohepatitis (NASH). Next, we explored the metabolic roles of NUPR1 in wild-type (Nupr1+/+ ) or Nupr1 knockout mice (Nupr1-/- ) fed with a high-fat diet (HFD) for 15 weeks. Immunohistochemical and mRNA analysis revealed NUPR1 expression is inversely correlated to hepatic steatosis progression. Mechanistically, we found NUPR1 participates in the activation of PPAR-α signaling via UPR. As PPAR-α signaling is controlled by UPR, collectively, these findings suggest a novel function for NUPR1 in protecting liver from metabolic distress by controlling lipid homeostasis, possibly through the UPR.

NUPR1 is a critical repressor of ferroptosis

Ferroptosis is a type of iron-dependent regulated cell death, representing an emerging disease-modulatory mechanism. Transcription factors play multiple roles in ferroptosis, although the key regulator for ferroptosis in iron metabolism remains elusive. Using NanoString technology, we identify NUPR1, a stress-inducible transcription factor, as a driver of ferroptosis resistance. Mechanistically, NUPR1-mediated LCN2 expression blocks ferroptotic cell death through diminishing iron accumulation and subsequent oxidative damage. Consequently, LCN2 depletion mimics NUPR1 deficiency with respect to ferroptosis induction, whereas transfection-enforced re-expression of LCN2 restores resistance to ferroptosis in NUPR1-deficient cells. Pharmacological or genetic blockade of the NUPR1-LCN2 pathway (using NUPR1 shRNA, LCN2 shRNA, pancreas-specific Lcn2 conditional knockout mice, or the small molecule ZZW-115) increases the activity of the ferroptosis inducer erastin and worsens pancreatitis, in suitable mouse models. These findings suggest a link between NUPR1-regulated iron metabolism and ferroptosis susceptibility.

Loss of <i>Nupr1</i> promotes engraftment by tuning the quiescence threshold of hematopoietic stem cell repository via regulating p53-checkpoint pathway

Hematopoietic stem cells (HSC) are dominantly quiescent under homeostasis, which is a key mechanism of maintaining the HSC pool for life-long hematopoiesis. Dormant HSC are poised to be immediately activated in certain conditions and can return to quiescence after homeostasis has been regained. At present, the molecular networks of regulating the threshold of HSC dormancy, if existing, remain largely unknown. Here, we show that deletion of Nupr1, a gene preferentially expressed in HSC, activated quiescent HSC under homeostasis, which conferred a competitive engraftment advantage for these HSC without compromising their stemness or multi-lineage differentiation capacity in serial transplantation settings. Following an expansion protocol, the Nupr1^-/- HSC proliferated more robustly than their wild-type counterparts in vitro. Nupr1 inhibits the expression of p53 and rescue of this inhibition offsets the engraftment advantage. Our data reveal a new role for Nupr1 as a regulator of HSC quiescence, which provides insights for accelerating the engraftment efficacy of HSC transplantation by targeting the HSC quiescence-controlling network.

Oncogenic Role of NUPR1 in Ovarian Cancer

Background

Nuclear protein 1 (NUPR1) plays a critical role in the development and progression of various types of human cancers. However, the role and mechanism of NUPR1 in ovarian cancer have not been elucidated. The purpose of this study was to investigate the effect of NUPR1 on ovarian cancer in vivo and in vitro.

Materials and Methods

Through the pretreatment of ovarian cancer cell lines, including A2780 and SKOV3 cells, the expression of NUPR1 was detected by RT-PCR and Western blot assays. When NUPR1 was overexpressed and knocked down in A2780 cells and overexpressed in SKOV3 cells, the MTT assays, colony formation assays and EdU assays were used to detect cell proliferation. Furthermore, cell invasion and migration ability were detected with the transwell assays. Cell cycle and apoptosis of A2780 cells after small interfering RNA-NUPR1 (siRNA-NUPR1) were detected by flow cytometry assays. Finally, the effect of NUPR1 gene silencing on the growth of ovarian cancer was evaluated by tumor xenograft experiment in vivo.

Results

The expression of NUPR1 protein in A2780 cells was significantly higher than that in ovarian surface epithelium (OSE) cells (P < 0.05). The results showed that downregulation of NUPR1 gene expression significantly inhibited the proliferation, migration and invasion ability of A2780 cells, and increased apoptosis of A2780 cells, which expressed relatively high levels of NUPR1. And the expression of apoptosis-related proteins caspase 3, caspase 9 and Bax was upregulated when NUPR1 was knocked out, while the expression of anti-apoptotic proteins of Bcl-2 and Bcl-xl was downregulated. At the same time, the opposite results were observed when NUPR1 was overexpressed in A2780 and SKOV3 cells. Notably, the effect of NUPR1 overexpression in A2780 cells could be partially or completely eliminated by treatment with the AKT inhibitor LY294002. In addition, NUPR1 knockdown could effectively inhibit tumor growth of mice in vivo.

Conclusion

In summary, NUPR1 has a carcinogenic effect in ovarian cancer, and the oncogenic effect of NUPR1 in ovarian cancer may be achieved by the AKT pathway.

Targeting NUPR1 for Cancer Treatment: A Risky Endeavor

NUPR1 is a transcription factor that has attracted great attention because of its various roles in cancer. Several studies were carried out to determine its molecular targets and mechanism of action to develop novel therapies against cancer. Here, we shed light on the role of NUPR1 in different types of cancer. NUPR1 regulates a complex network of pathways that may be affected by its silencing, which can cause varying effects. Its role in some types of cancer has been reported but remains incompletely understood, whereas its roles in other types of cancers have not been reported yet. Therefore, targeting NUPR1 for cancer treatment remains challenging and risky.

The Paralogue of the Intrinsically Disordered Nuclear Protein 1 Has a Nuclear Localization Sequence that Binds to Human Importin α3

Numerous carrier proteins intervene in protein transport from the cytoplasm to the nucleus in eukaryotic cells. One of those is importin α, with several human isoforms; among them, importin α3 (Impα3) features a particularly high flexibility. The protein NUPR1L is an intrinsically disordered protein (IDP), evolved as a paralogue of nuclear protein 1 (NUPR1), which is involved in chromatin remodeling and DNA repair. It is predicted that NUPR1L has a nuclear localization sequence (NLS) from residues Arg51 to Gln74, in order to allow for nuclear translocation. We studied in this work the ability of intact NUPR1L to bind Impα3 and its depleted species, ∆Impα3, without the importin binding domain (IBB), using fluorescence, isothermal titration calorimetry (ITC), circular dichroism (CD), nuclear magnetic resonance (NMR), and molecular docking techniques. Furthermore, the binding of the peptide matching the isolated NLS region of NUPR1L (NLS-NUPR1L) was also studied using the same methods. Our results show that NUPR1L was bound to Imp α3 with a low micromolar affinity (~5 μM). Furthermore, a similar affinity value was observed for the binding of NLS-NUPR1L. These findings indicate that the NLS region, which was unfolded in isolation in solution, was essentially responsible for the binding of NUPR1L to both importin species. This result was also confirmed by our in silico modeling. The binding reaction of NLS-NUPR1L to ∆Impα3 showed a larger affinity (i.e., lower dissociation constant) compared with that of Impα3, confirming that the IBB could act as an auto-inhibition region of Impα3. Taken together, our findings pinpoint the theoretical predictions of the NLS region in NUPR1L and, more importantly, suggest that this IDP relies on an importin for its nuclear translocation.

A Phosphorylation-Induced Switch in the Nuclear Localization Sequence of the Intrinsically Disordered NUPR1 Hampers Binding to Importin

Several carrier proteins are involved in protein transport from the cytoplasm to the nucleus in eukaryotic cells. One of those is importin α, of which there are several human isoforms; among them, importin α3 (Impα3) has a high flexibility. The protein NUPR1, a nuclear protein involved in the cell-stress response and cell cycle regulation, is an intrinsically disordered protein (IDP) that has a nuclear localization sequence (NLS) to allow for nuclear translocation. NUPR1 does localize through the whole cell. In this work, we studied the affinity of the isolated wild-type NLS region (residues 54–74) of NUPR1 towards Impα3 and several mutants of the NLS region by using several biophysical techniques and molecular docking approaches. The NLS region of NUPR1 interacted with Impα3, opening the way to model the nuclear translocation of disordered proteins. All the isolated NLS peptides were disordered. They bound to Impα3 with low micromolar affinity (1.7–27 μM). Binding was hampered by removal of either Lys65 or Lys69 residues, indicating that positive charges were important; furthermore, binding decreased when Thr68 was phosphorylated. The peptide phosphorylated at Thr68, as well as four phospho-mimetic peptides (all containing the Thr68Glu mutation), showed the presence of a sequential NN(i,i + 1) nuclear Overhauser effect (NOE) in the 2D-¹H-NMR (two-dimensional–proton NMR) spectra, indicating the presence of turn-like conformations. Thus, the phosphorylation of Thr68 modulates the binding of NUPR1 to Impα3 by a conformational, entropy-driven switch from a random-coil conformation to a turn-like structure.

BRCA-related ATM-mediated DNA double-strand break repair and ovarian aging

BACKGROUND

Oocyte aging has significant clinical consequences, and yet no treatment exists to address the age-related decline in oocyte quality. The lack of progress in the treatment of oocyte aging is due to the fact that the underlying molecular mechanisms are not sufficiently understood. BRCA1 and 2 are involved in homologous DNA recombination and play essential roles in ataxia telangiectasia mutated (ATM)-mediated DNA double-strand break (DSB) repair. A growing body of laboratory, translational and clinical evidence has emerged within the past decade indicating a role for BRCA function and ATM-mediated DNA DSB repair in ovarian aging.

OBJECTIVE AND RATIONALE

Although there are several competing or complementary theories, given the growing evidence tying BRCA function and ATM-mediated DNA DSB repair mechanisms in general to ovarian aging, we performed this review encompassing basic, translational and clinical work to assess the current state of knowledge on the topic. A clear understanding of the mechanisms underlying oocyte aging may result in targeted treatments to preserve ovarian reserve and improve oocyte quality.

SEARCH METHODS

We searched for published articles in the PubMed database containing key words, BRCA, BRCA1, BRCA2, Mutations, Fertility, Ovarian Reserve, Infertility, Mechanisms of Ovarian Aging, Oocyte or Oocyte DNA Repair, in the English-language literature until May 2019. We did not include abstracts or conference proceedings, with the exception of our own.

OUTCOMES

Laboratory studies provided robust and reproducible evidence that BRCA1 function and ATM-mediated DNA DSB repair, in general, weakens with age in oocytes of multiple species including human. In both women with BRCA mutations and BRCA-mutant mice, primordial follicle numbers are reduced and there is accelerated accumulation of DNA DSBs in oocytes. In general, women with BRCA1 mutations have lower ovarian reserves and experience earlier menopause. Laboratory evidence also supports critical role for BRCA1 and other ATM-mediated DNA DSB repair pathway members in meiotic function. When laboratory, translational and clinical evidence is considered together, BRCA-related ATM-mediated DNA DSB repair function emerges as a likely regulator of ovarian aging. Moreover, DNA damage and repair appear to be key features in chemotherapy-induced ovarian aging.

WIDER IMPLICATIONS

The existing data suggest that the BRCA-related ATM-mediated DNA repair pathway is a strong candidate to be a regulator of oocyte aging, and the age-related decline of this pathway likely impairs oocyte health. This knowledge may create an opportunity to develop targeted treatments to reverse or prevent physiological or chemotherapy-induced oocyte aging. On the immediate practical side, women with BRCA or similar mutations may need to be specially counselled for fertility preservation.

Nuclear protein 1 imparts oncogenic potential and chemotherapeutic resistance in cancer

Nuclear protein 1 (NUPR1) also known as p8 and candidate of metastasis 1 (COM1) functions as a transcriptional regulator, and plays a role in cell cycle, DNA damage response, apoptosis, autophagy, and chromatin remodeling in response to various cellular stressors. Since it was first suggested to contribute to cancer development and progression in 1999, a number of studies have sought to reveal its function. However, NUPR1 and its biological relevance in cancer have proven difficult to pinpoint. Based on evidence of NUPR1 expression in cancers, its function extends from carcinogenesis and tumorigenesis to metastasis and chemotherapeutic resistance. A tumor suppressive function of NUPR1 has also been documented in multiple cancers. By and large, literature involving NUPR1 and cancer is confined to pancreatic and breast cancers, yet significant progress has been made with respect to NUPR1 expression and its function in lung, colorectal, blood, and prostate cancers, among others. Recent evidence strongly supports the notion that NUPR1 is key in chemotherapeutic resistance by mediating both anti-apoptotic activity and autophagy when challenged with anti-cancer compounds. Therefore, it is of significant importance to understand the broad range of molecular functions directed by NUPR1. In this review, NUPR1 expression and its role in breast, lung, and colorectal cancer development and progression will be addressed.

NUPR1 preserves insulin secretion of pancreatic β-cells during inflammatory stress by multiple low-dose streptozotocin and high-fat diet

Obesity is associated with dyslipidemia and subclinical inflammation that promotes metabolic disturbances including insulin resistance and pancreatic β-cell dysfunction. The nuclear protein, transcriptional regulator 1 (NUPR1) responds to cellular stresses and features tissue protective properties. To characterize the role of NUPR1 in endocrine pancreatic islets during inflammatory stress, we generated transgenic mice with β-cell-specific Nupr1 overexpression (βNUPR1). Under normal conditions, βNUPR1 mice did not differ from wild type (WT) littermates and display normal glucose homeostasis and β-cell mass. For induction of inflammatory conditions, mice were treated with multiple low-dose streptozotocin (mld-STZ) and/or fed a high-fat diet (HFD). All treatments significantly worsened glycaemia in WT mice, while βNUPR1 mice substantially preserved insulin secretion and glucose tolerance. HFD increased β-cell mass in all animals, with βNUPR1 mice tending to show higher values. The improved outcome of βNUPR1 mice was accompanied by decreased NF-κB activation and lymphocyte infiltration in response to mld-STZ. In vitro, isolated βNUPR1 islets preserved insulin secretion and content with insignificantly low apoptosis during culture stress and IL-1β exposure. These findings suggest that NUPR1 plays a vital role in the protection of β-cells from apoptosis, related degradation of insulin storages and subsequent secretion during inflammatory and obesity-related tissue stress.

Targeting intrinsically disordered proteins involved in cancer

Intrinsically disordered proteins (IDPs) do not have a well-defined structure under physiological conditions, but they have key roles in cell signaling and regulation, and they are frequently related to the development of diseases, such as cancer and other malignancies. This has converted IDPs in attractive therapeutic targets; however, targeting IDPs is challenging because of their dynamic nature. In the last years, different experimental and computational approaches, as well as the combination of both, have been explored to identify molecules to target either the hot-spots or the allosteric sites of IDPs. In this review, we summarize recent developments in successful targeting of IDPs, all of which are involved in different cancer types. The strategies used to develop and design (or in one particular example, to repurpose) small molecules targeting IDPs are, in a global sense, similar to those used in well-folded proteins: (1) screening of chemically diverse or target-oriented compound libraries; or (2) study of the interfaces involved in recognition of their natural partners, and design of molecular candidates capable of binding to such binding interface. We describe the outcomes of using these approaches in targeting IDPs involved in cancer, in the view to providing insight, to target IDPs in general. In a broad sense, the designed small molecules seem to target the most hydrophobic regions of the IDPs, hampering macromolecule (DNA or protein)-IDP interactions; furthermore, in most of the molecule-IDP complexes described so far, the protein remains disordered.

Quercetin induced NUPR1-dependent autophagic cell death by disturbing reactive oxygen species homeostasis in osteosarcoma cells

Osteosarcoma is a primary bone aggressive cancer, affecting adolescents worldwide. Quercetin (a natural polyphenolic compound) is a polyphenolic flavonoid compound found in a variety of plants. It has been demonstrated to exert cytostatic activity against a variety of human cancer, including the human osteosarcoma. However, its efficacy in the treatment of osteosarcoma and the underlying antitumor mechanism has not been fully elucidated yet. In this study, we exposed MG-63 cells to different concentrations of quercetin (50, 100 and 200 µM) for 24 h. Here, we show that quercetin increased autophagic flux in the MG-63 cells, as evidenced by the upregulation of LC3B-II/LC3B-I and downregulation of P62/SQSTM1. Moreover, the autophagy inhibitor Bafilomycin A1 or genetic blocking autophagy with ATG5 knockdown decreased quercetin-induced cell death, indicating quercetin triggered autophagic cell death in MG-63 cells. Specifically, quercetin increased NUPR1 expression and activated of NUPR1 reporter activity, which contributed to the expression of autophagy-related genes and subsequent initiated autophagic cell death in osteosarcoma cells. Importantly, the increased expression NUPR1 were tightly related to the disturbance of reactive oxygen species (ROS) homeostasis, which could be prevented by inhibiting intracellular ROS with NAC. Finally, NAC also abolished quercetin-induced autophagic cell death in vivo. Taken together, these data demonstrate that quercetin induces osteosarcoma cell death via inducing excessive autophagy, which is mediated through the ROS-NUPR1 pathway. Quercetin application may be a promising and practical strategy for osteosarcoma treatment in clinical practice.

Life with the pancreas: A personal experience

This review article has primary objective to summarize pancreatic research which has been done in our laboratory since 1965, the first year of the author's registration in the Ph.D. program at the University of Sherbrooke (Canada). It covers the following major topics of pancreatic physiology: controls of pancreatic adaptation to diet, control of pancreatic enzyme secretion, control of pancreatic enzyme synthesis, control of pancreatic growth, intracellular events stimulated during pancreatic growth, pancreas regeneration after pancreatitis and pancreatectomy, the pancreatic cholecystokinin receptor types 1 and 2, growth control and cell signaling in pancreatic cancer cells and finally, cystic fibrosis.

Targeting the Stress-Induced Protein NUPR1 to Treat Pancreatic Adenocarcinoma

Cancer cells activate stress-response mechanisms to adapt themselves to a variety of stressful conditions. Among these protective mechanisms, those controlled by the stress-induced nuclear protein 1 (NUPR1 ) belong to the most conserved ones. NUPR1 is an 82-residue-long, monomeric, basic and intrinsically disordered protein (IDP), which was found to be invariably overexpressed in some, if not all, cancer tissues. Remarkably, we and others have previously showed that genetic inactivation of the Nupr1 gene antagonizes the growth of pancreatic cancer as well as several other tumors. With the use of a multidisciplinary strategy by combining biophysical, biochemical, bioinformatic, and biological approaches, a trifluoperazine-derived compound, named ZZW-115, has been identified as an inhibitor of the NUPR1 functions. The anticancer activity of the ZZW-115 was first validated on a large panel of cancer cells. Furthermore, ZZW-115 produced a dose-dependent tumor regression of the tumor size in xenografted mice. Mechanistically, we have demonstrated that NUPR1 binds to several importins. Because ZZW-115 binds NUPR1 through the region around the amino acid Thr68, which is located into the nuclear location signal (NLS) region of the protein, we demonstrated that treatment with ZZW-115 inhibits completely the translocation of NUPR1 from the cytoplasm to the nucleus by competing with importins.

Dynamics of the intrinsically disordered protein NUPR1 in isolation and in its fuzzy complexes with DNA and prothymosin α

Intrinsically disordered proteins (IDPs) explore diverse conformations in their free states and, a few of them, also in their molecular complexes. This functional plasticity is essential for the function of IDPs, although their dynamics in both free and bound states is poorly understood. NUPR1 is a protumoral multifunctional IDP, activated during the acute phases of pancreatitis. It interacts with DNA and other IDPs, such as prothymosin α (ProTα), with dissociation constants of ~0.5 μM, and a 1:1 stoichiometry. We studied the structure and picosecond-to-nanosecond (ps-ns) dynamics by using both NMR and SAXS in: (i) isolated NUPR1; (ii) the NUPR1/ProTα complex; and (iii) the NUPR1/double stranded (ds) GGGCGCGCCC complex. Our SAXS findings show that NUPR1 remained disordered when bound to either partner, adopting a worm-like conformation; the fuzziness of bound NUPR1 was also pinpointed by NMR. Residues with the largest values of the relaxation rates (R₁, R_1ρ, R₂ and η_xy), in the free and bound species, were mainly clustered around the 30s region of the sequence, which agree with one of the protein hot-spots already identified by site-directed mutagenesis. Not only residues in this region had larger relaxation rates, but they also moved slower than the rest of the molecule, as indicated by the reduced spectral density approach (RSDA). Upon binding, the energy landscape of NUPR1 was not funneled down to a specific, well-folded conformation, but rather its backbone flexibility was kept, with distinct motions occurring at the hot-spot region.

Inhibition of ROS/NUPR1-dependent autophagy antagonises repeated cadmium exposure -induced oral squamous cell carcinoma cell migration and invasion

Cadmium (Cd), an established carcinogen, is a risk factor for oral squamous cell carcinoma (OSCC). Macroautophagy/autophagy is proposed to play a pivotal role in Cd-mediated carcinogenic activity. However, the mechanisms underlying Cd-induced autophagy are poorly understood. In the present study, a CAL27 OSCC cell line exposed to 10^-6 M Cd for 8 weeks was used as a model system. Repeated Cd exposure induced significant migration and invasion of CAL27 cells. Furthermore, we showed that Cd increased the autophagic flux in CAL27 cells, as evidenced by the upregulation of LC3-II and the downregulation of P62/SQSTM1. The genetic blocking of autophagy inhibited Cd-induced migration and invasion, indicating a carcinogenic role of autophagy in Cd-treated CAL27 cells. Cd-induced NUPR1 expression, which contributes to lysosomal biogenesis and expression of autophagy-related gene, was found to mechanistically initiate autophagy in CAL27 cells. Of note, NUPR1 shRNA abolished Cd-induced autophagy both in vitro and in vivo. We also found that Cd triggered the generation of MDA in a xenograft tumour model and that N-acetyl-l-cysteine, a reactive oxygen species (ROS) scavenger, abrogated the effects of Cd on NUPR1-dependent autophagy in vivo. Taken together, these results demonstrate that ROS-dependent NUPR1-mediated autophagy plays an important role in repeated Cd exposure -induced cell growth, migration and invasion in OSCC cells.

Pancreatic Ductal Deletion of Hnf1b Disrupts Exocrine Homeostasis, Leads to Pancreatitis, and Facilitates Tumorigenesis

BACKGROUND & AIMS

The exocrine pancreas consists of acinar cells that produce digestive enzymes transported to the intestine through a branched ductal epithelium. Chronic pancreatitis is characterized by progressive inflammation, fibrosis, and loss of acinar tissue. These changes of the exocrine tissue are risk factors for pancreatic cancer. The cause of chronic pancreatitis cannot be identified in one quarter of patients. Here, we investigated how duct dysfunction could contribute to pancreatitis development.

METHODS

The transcription factor Hnf1b, first expressed in pancreatic progenitors, is strictly restricted to ductal cells from late embryogenesis. We previously showed that Hnf1b is crucial for pancreas morphogenesis but its postnatal role still remains unelucidated. To investigate the role of pancreatic ducts in exocrine homeostasis, we inactivated the Hnf1b gene in vivo in mouse ductal cells.

RESULTS

We uncovered that postnatal Hnf1b inactivation in pancreatic ducts leads to chronic pancreatitis in adults. Hnf1bΔ^duct mutants show dilatation of ducts, loss of acinar cells, acinar-to-ductal metaplasia, and lipomatosis. We deciphered the early events involved, with down-regulation of cystic disease-associated genes, loss of primary cilia, up-regulation of signaling pathways, especially the Yap pathway, which is involved in acinar-to-ductal metaplasia. Remarkably, Hnf1bΔ^duct mutants developed pancreatic intraepithelial neoplasia and promote pancreatic intraepithelial neoplasia progression in concert with KRAS. We further showed that adult Hnf1b inactivation in pancreatic ducts is associated with impaired regeneration after injury, with persistent metaplasia and initiation of neoplasia.

CONCLUSIONS

Loss of Hnf1b in ductal cells leads to chronic pancreatitis and neoplasia. This study shows that Hnf1b deficiency may contribute to diseases of the exocrine pancreas and gains further insight into the etiology of pancreatitis and tumorigenesis.

Deficiency of stress-associated gene Nupr1 increases bone volume by attenuating differentiation of osteoclasts and enhancing differentiation of osteoblasts

Nuclear protein 1 (NUPR1) is a multifunctional stress-induced protein involved in regulating tumorigenesis, apoptosis, and autophagy. Bone homeostasis is maintained by bone-resorbing osteoclasts and bone-forming osteoblasts and osteocytes. We aimed to determine the role of NUPR1 in bone metabolism. Using microcomputed tomography, we found that mice lacking Nupr1 exhibited increased bone volume. Histologic analysis showed that Nupr1 deficiency decreased osteoclast numbers but increased osteoblast numbers and osteoid formation. In vitro culture of bone marrow macrophages showed that receptor activator of NF-κB ligand-induced osteoclastogenesis was down-regulated in Nupr1-deficient mice. In contrast, primary osteoblasts from Nupr1-deficient mice revealed that proliferation of osteoblasts and expression of bone matrix proteins were markedly enhanced. In addition, expression of autophagy-related genes, formation of autophagosomes, and cell survival were up-regulated in Nupr1-deficient osteoblasts. In contract, deletion of Nupr1 reduced the formation of osteocyte cellular projection, which is an indicator of mature osteocytes. Importantly, we found that the expression of sclerostin (Sost), an inhibitor of bone formation, was down-regulated in the osteoblasts and osteocytes of Nupr1-deficient mice. Conversely, Nupr1 overexpression enhanced Sost expression in primary osteoblasts. Collectively, these results indicate that Nupr1 deficiency increases bone volume by attenuating production of Sost and osteoclastogenesis and enhancing differentiation of osteoblasts.-Shiraki, M., Xu, X., Iovanna, J. L., Kukita, T., Hirata, H., Kamohara, A., Kubota, Y., Miyamoto, H., Mawatari, M., Kukita, A. Deficiency of stress-associated gene Nupr1 increases bone volume by attenuating differentiation of osteoclasts and enhancing differentiation of osteoblasts.

Induction of nuclear protein-1 by thyroid hormone enhances platelet-derived growth factor A mediated angiogenesis in liver cancer

Background & Aims: Hepatocellular carcinoma (HCC) is among the leading causes of cancer deaths worldwide. Many studies indicate that disruption of cellular thyroid hormone signaling promotes HCC progression. However, the mechanisms underlying the regulation of genes downstream of thyroid hormone actions in HCC have remained elusive. In the current study, we identified NUPR1 (nuclear protein-1), a stress-induced protein that overexpresses in various neoplasia, is upregulated by triiodothyronine/thyroid hormone receptor (T₃/TR) signaling and aimed to elucidate its role in angiogenesis in cancer progression.

Methods: Quantitative reverse transcription-PCR, luciferase promoter and chromatin immunoprecipitation assays were performed to identify the NUPR1 regulatory mechanism by T₃/TR. In vitro and In vivo vascular formations were performed to detect the angiogenic function of NUPR1. Human angiogenesis arrays were performed to identify the downstream angiogenic pathway. The sorafenib resistant ability of TR/NUPR1 was further examined in vitro and in vivo. Clinical relevance of TR, NUPR1 and platelet-derived growth factor A (PDGFA) were investigate in HCC samples using qRT-PCR and western blot.

Results: Our experiments disclosed positive regulation of NUPR1 expression by T₃/TR through direct binding to the -2066 to -1910 region of the NUPR1 promoter. Elevated NUPR1 and TR expression link to poor survival in clinical HCC specimens. An analysis of clinicopathological parameters showed that expression of NUPR1 is associated with vascular invasion and pathology stage. Functional studies revealed that NUPR1 induced endothelial cell angiogenesis in vitro and in vivo. Using a human angiogenesis array, we identified PDGFA as a target of NUPR1 in the downstream angiogenic pathway. NUPR1 induced transcription of PDGFA through direct binding to the corresponding promoter region, and inhibition of the PDGFA signaling pathway impaired angiogenesis in human umbilical vein endothelial cells (HUVECs). Notably, the angiogenic effects of NUPR1/PDGFA were mediated by the MEK/ERK signaling pathway. TR/NUPR1 expression increased cell viability and resistance to sorafenib treatment. Moreover NUPR1 expression was positively correlated with TRα, TRβ, and PDGFA expression.

Conclusions: We propose that the T₃/TR/NUPR1/PDGFA/MEK/ERK axis has a vital role in hepatocarcinogenesis and suggest NUPR1 as a potential therapeutic target in HCC.

Pancreatic Cancer Heterogeneity Can Be Explained Beyond the Genome

Pancreatic ductal adenocarcinoma (PDAC) remains a major health problem because it induces almost systematic mortality. Carcinogenesis begins with genetic aberrations which trigger epigenetic modifications. While genetic mutations initiate tumorigenesis, they are unable to explain the vast heterogeneity observed among PDAC patients. Instead, epigenetic changes drive transcriptomic alterations that can regulate the malignant phenotype. The contribution of factors from the environment and tumor microenvironment defines different epigenetic landscapes that outline two clinical subtypes: basal, with the worst prognosis, and classical. The epigenetic nature of PDAC, as a reversible phenomenon, encouraged several studies to test epidrugs. However, these drugs lack specificity and although there are epigenetic patterns shared by all PDAC tumors, there are others that are specific to each subtype. Molecular characterization of the epigenetic mechanisms underlying PDAC heterogeneity could be an invaluable tool to predict personalized therapies, stratify patients and search for novel therapies with more specific phenotype-based targets. Novel therapeutic strategies using current anticancer compounds or existing drugs used in other pathologies, alone or in combination, could be used to kill tumor cells or convert aggressive tumors into a more benign phenotype.

Ligand-based design identifies a potent NUPR1 inhibitor exerting anticancer activity via necroptosis

Intrinsically disordered proteins (IDPs) are emerging as attractive drug targets by virtue of their prevalence in various diseases including cancer. Drug development targeting IDPs is challenging because they have dynamical structure features and conventional drug design is not applicable. NUPR1 is an IDP playing an important role in pancreatic cancer. We previously reported that Trifluoperazine (TFP), an antipsychotic agent, was capable of binding to NUPR1 and inhibiting tumors growth. Unfortunately, TFP showed strong central nervous system side-effects. In this work, we undertook a multidisciplinary approach to optimize TFP, based on the synergy of computer modeling, chemical synthesis, and a variety of biophysical, biochemical and biological evaluations. A family of TFP-derived compounds was produced and the most active one, named ZZW-115, showed a dose-dependent tumor regression with no neurological effects and induced cell death mainly by necroptosis. This study opens a new perspective for drug development against IDPs, demonstrating the possibility of successful ligand-based drug design for such challenging targets.

Gene Expression Analysis of the Activating Factor 3/Nuclear Protein 1 Axis in a Non-alcoholic Steatohepatitis Mouse Model

Background

Nonalcoholic fatty liver disease/steatohepatitis (NAFLD/NASH) is a chronic liver disease related to metabolic syndrome that can progress to liver cirrhosis. The involvement of the endoplasmic reticulum (ER) stress response in NAFLD progression and the roles played by activating factor 3 (ATF3) and the downstream nuclear protein 1 (NUPR1) are poorly understood. The aim of this study was to determine the gene expression profiles around the ATF3/NUPR1 axis in relation to the development of NAFLD using novel mouse models.

Methods

Fatty liver Shionogi (FLS) mice (n = 12) as a NAFLD model and FLS-ob/ob mice (n = 28) as a NASH model were fed a standard diet. The FLS mice were sacrificed at 24 weeks of age as a control, whereas the FLS-ob/ob mice were sacrificed at 24, 36, and 48 weeks of age. Hepatic steatosis, inflammation, and fibrosis were evaluated by biochemical, histological, and gene expression analyses. The expression levels of the ER-stress related genes Jun proto-oncogene (C-jun), Atf3, Nupr1, and C/EBP homologous protein (Chop) were measured in liver tissue. Apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining.

Results

Control mice demonstrated hepatic steatosis alone without apparent fibrosis. On the other hand, FLS-ob/ob mice showed severe steatohepatitis at both 24 and 36 weeks of age and severe fibrosis at both 36 and 48 weeks of age. The expression levels of Atf3, Nupr-1, and C-jun significantly increased from 24 to 48 weeks of age in FLS-ob/ob mice compared with control mice. The expression level of Chop was already high in FLS mice and maintained similar levels in FLS-ob/ob mice; the expression level was consistent with the percentage of TUNEL-positive cells.

Conclusion

The ATF3/NUPR1 axis plays a pivotal role in NASH progression in association with C-jun and Chop and appears to induce apoptosis from early steatosis in the NASH model mice.

The onus of cannabinoids in interrupting the molecular odyssey of breast cancer: A critical perspective on UPRER and beyond

Cannabinoids, commonly used for medicinal and recreational purposes, consist of various complex hydrophobic molecules obtained from Cannabis sativa L. Acting as an inhibitory molecule; they have been investigated for their antineoplastic effect in various breast tumor models. Lately, it was found that cannabinoid treatment not only stimulates autophagy-mediated apoptotic death of tumor cells through unfolded protein response (UPR^ER) activated downstream effectors, but also imposes cell cycle arrest. The exploitation of UPR^ER tumors as such is believed to be a major molecular event and is therefore employed in understanding the development and progression of breast tumor. Simultaneously, the data on clinical trials following administration of cannabinoid is currently being explored to find its role not only in palliation but also in the treatment of breast cancer. The present study summarizes new achievements in understanding the extent of therapeutic progress and highlights recent developments in cannabinoid biology towards achieving a better cure of breast cancer through the exploitation of different cannabinoids.