N-myc downstream regulated gene 1/Cap43 suppresses tumor growth and angiogenesis of pancreatic cancer through attenuation of inhibitor of kappaB kinase beta expression

Multi-modal mechanisms of the metastasis suppressor, NDRG1: Inhibition of WNT/β-catenin signaling by stabilization of protein kinase Cα

The metastasis suppressor, N-myc downstream regulated gene-1 (NDRG1), inhibits pro-oncogenic signaling in pancreatic cancer (PC). This investigation dissected a novel mechanism induced by NDRG1 on WNT/β-catenin signaling in multiple PC cell types. NDRG1 overexpression decreased β-catenin and downregulated glycogen synthase kinase-3β (GSK-3β) protein levels and its activation. However, β-catenin phosphorylation at Ser33, Ser37, and Thr41 are classically induced by GSK-3β was significantly increased after NDRG1 overexpression, suggesting a GSK-3β-independent mechanism. Intriguingly, NDRG1 overexpression upregulated protein kinase Cα (PKCα), with PKCα silencing preventing β-catenin phosphorylation at Ser33, Ser37, and Thr41, and decreasing β-catenin expression. Further, NDRG1 and PKCα were demonstrated to associate, with PKCα stabilization occurring after NDRG1 overexpression. PKCα half-life increased from 1.5 ± 0.8 h (3) in control cells to 11.0 ± 2.5 h (3) after NDRG1 overexpression. Thus, NDRG1 overexpression leads to the association of NDRG1 with PKCα and PKCα stabilization, resulting in β-catenin phosphorylation at Ser33, Ser37, and Thr41. The association between PKCα, NDRG1, and β-catenin was identified, with the formation of a potential metabolon that promotes the latter β-catenin phosphorylation. This anti-oncogenic activity of NDRG1 was multi-modal, with the above mechanism accompanied by the downregulation of the nucleo-cytoplasmic shuttling protein, p21-activated kinase 4 (PAK4), which is involved in β-catenin nuclear translocation, inhibition of AKT phosphorylation (Ser473), and decreased β-catenin phosphorylation at Ser552 that suppresses its transcriptional activity. These mechanisms of NDRG1 activity are important to dissect to understand the marked anti-cancer efficacy of NDRG1-inducing thiosemicarbazones that upregulate PKCα and inhibit WNT signaling.

NDRG1 overcomes resistance to immunotherapy of pancreatic ductal adenocarcinoma through inhibiting ATG9A-dependent degradation of MHC-1

AIMS

Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease that is resistant to immune checkpoint blockade (ICB) therapies. Emerging evidence suggests that NDRG1 may be an important target for the development of new therapies for PDAC. Herein, we investigated the novel roles of NDRG1 and Combretastatin A-4 (CA-4) in the treatment of PDAC ICB resistance.

METHODS

Enrichment of MHC class I was detected by RNA sequence and verified by RT-qPCR and immunoblotting in NDRG1-knockdown human pancreatic cancer cell lines. The protein degradation mode was found by stimulation with various inhibitors, and the autophagy degradation pathway was found by immunoprecipitation and immunolocalization. The roles of NDRG1 and MHC-I in immunotherapy were investigated by orthotopic solid tumors, histology, immunohistochemistry, multiplex immunofluorescence staining and flow cytometry.

RESULTS

Here, we identified a previously undescribed role of NDRG1 in activating major histocompatibility complex class 1 (MHC-1) expression in pancreatic ductal adenocarcinoma (PDAC) cells through lysosomal-autophagy-dependent degradation. In mouse models of PDAC, either tumor cell overexpression or pharmacologic activation of NDRG1 leads to MHC-1 upregulation in tumor cells, which in turn promotes the infiltration and activity of CD8 + T cells, enhances anti-tumor immunity, and overcomes resistance to ICB therapy. Moreover, combination therapy of CA-4 and ICB overcomes the drug resistance of pancreatic cancer to ICB therapy. In PDAC patients, NDRG1 expression correlates with high MHC-1 expression and better survival.

CONCLUSION

Our results reveal NDRG1 in PDAC cancer cells as a tumor suppressor and suggest that pharmaceutically targeting NDRG1 is a promising way to overcome pancreatic cancer resistance to immunotherapy and provides a potential therapeutic strategy for the treatment of pancreatic cancer patients.

Association between NDRG1 protein expression and aggressive features of breast cancer: a systematic review and meta-analysis

BACKGROUND

N-myc downstream-regulated gene-1 (NDRG1) is well-described as a potent metastasis suppressor, but its role in human breast cancer remains controversial and unclear. Therefore, the present study utilized a systematic review and meta-analysis approach to synthesize the association between NDRG1 protein expression and the aggressive characteristics of breast cancer.

METHODS

The protocol for the systematic review and meta-analysis was registered on the PROSPERO website (CRD42023414814). Relevant articles were searched for in PubMed, Scopus, Embase, MEDLINE, and Ovid between March 30, 2023, and May 5, 2023. The included studies were critically evaluated using the Joanna Briggs Institute critical appraisal tools. The results from individual studies were qualitatively synthesized using textual narrative synthesis. Using a random-effects model, the pooled log odds ratio of effect estimate was used to look at the link between NDRG1 protein expression and aggressive features of breast cancer, such as tumor grade, tumor stage, metastasis to the axillary lymph nodes, and hormonal receptor status.

RESULTS

A total of 1423 articles were retrieved from the electronic database search, and six studies that met the eligibility criteria were included for synthesis. There was an association between the expression of NDRG1 protein and the status of the axillary lymph nodes (P = 0.01, log Odds Ratio (OR): 0.59, 95% Confidence Interval (CI): 0.13-1.05, I2: 24.24%, 292 breast cancer cases with positive axillary lymph nodes and 229 breast cancer cases with negative axillary lymph nodes, 4 studies). NDRG1 protein expression and human epidermal growth factor receptor 2 (Her2) status were found to have a negative relationship (P = 0.01, log OR: -0.76, 95% CI: -1.32-(-0.20), I2: 32.42%, 197 breast cancer cases with Her2 positive and 272 breast cancer cases with Her2 negative, 3 studies). No correlation was found between NDRG1 protein expression and tumor grade (P = 0.10), estrogen receptor (ER) status (P = 0.57), or progesterone receptor (PR) status (P = 0.41).

CONCLUSION

The study concluded that increased NDRG1 protein expression was associated with increased metastasis of the tumor to the axillary lymph node. Additionally, increased NDRG1 protein expression was observed in Her2-negative breast cancer, suggesting its role in both less aggressive and more aggressive behavior depending on breast cancer subtypes. Based on the findings of the meta-analysis, an increase in NDRG1 protein expression was associated with aggressive characteristics of breast cancer.

Integrated single-cell and bulk RNA sequencing revealed the molecular characteristics and prognostic roles of neutrophils in pancreatic cancer

Pancreatic cancer, one of the most prevalent tumors of the digestive system, has a dismal prognosis. Cancer of the pancreas is distinguished by an inflammatory tumor microenvironment rich in fibroblasts and different immune cells. Neutrophils are important immune cells that infiltrate the microenvironment of pancreatic cancer tumors. The purpose of this work was to examine the complex mechanism by which neutrophils influence the carcinogenesis and development of pancreatic cancer and to construct a survival prediction model based on neutrophil marker genes. We incorporated the GSE111672 dataset, comprising RNA expression data from 27,000 cells obtained from 3 patients with PC, and conducted single-cell data analysis. Thorough investigation of pancreatic cancer single-cell RNA sequencing data found 350 neutrophil marker genes. Using The Cancer Genome Atlas (TCGA), GSE28735, GSE62452, GSE57495, and GSE85916 datasets to gather pancreatic cancer tissue transcriptome data, and consistent clustering was used to identify two categories for analyzing the influence of neutrophils on pancreatic cancer. Using the Random Forest algorithm and Cox regression analysis, a survival prediction model for pancreatic cancer was developed, the model showed independent performance for survival prognosis, clinic pathological features, immune infiltration, and drug sensitivity. Multivariate Cox analysis findings revealed that the risk scores derived from predictive models is independent prognostic markers for pancreatic patients. In conclusion, based on neutrophil marker genes, this research created a molecular typing and prognostic grading system for pancreatic cancer, this system was very accurate in predicting the prognosis, tumor immune microenvironment status, and pharmacological treatment responsiveness of pancreatic cancer patients.

Disulfiram suppresses epithelial-mesenchymal transition (EMT), migration and invasion in cervical cancer through the HSP90A/NDRG1 pathway

Disulfiram (DSF) has proven to be a promising anti-tumor drug in preclinical studies. However, its anti-cancer mechanism has not yet been elucidated. As an activator in tumor metastasis, N-myc downstream regulated gene-1 (NDRG1) is involved in multiple oncogenic signaling pathways and is upregulated by cell differentiation signals in various cancer cell lines. DSF treatment results in a significant reduction in NDRG1, while down-regulated NDRG1 has a pronounced effect on invading cancer cells, as shown in our previous work. Here, in vitro and in vivo experiments confirm that DSF contributes to regulating tumor growth, EMT, and the migration and invasion of cervical cancer. Furthermore, our results show DSF binds to the ATP-binding pocket in the N-terminal domain of HSP90A, thereby affecting the expression of its client protein NDRG1. To our knowledge, this is the first report of DSF binding to HSP90A. In conclusion, this study sheds light on the molecular mechanism by which DSF inhibits tumor growth and metastasis through the HSP90A/NDRG1/β-catenin pathway in cervical cancer cells. These findings provide novel insights into the mechanism underlying DSF function in cancer cells.

CRISPR/Cas9 Screen in Gastric Cancer Patient-Derived Organoids Reveals KDM1A-NDRG1 Axis as a Targetable Vulnerability

Viability CRISPR screens have proven indispensable in parsing genome function. However, their application in new, more physiologically relevant culturing systems like patient-derived organoids (PDOs) has been much slower. To probe epigenetic contribution to gastric cancer (GC), the third leading cause of cancer-related deaths worldwide, the first negative selection CRISPR screen in GC PDOs that faithfully preserve primary tumor characteristics is performed. Extensive quality control measurements showing feasibility of CRISPR screens in primary organoid culture are provided. The screen reveals the histone lysine demethylase-1A (KDM1A) to constitute a GC vulnerability. Both genetic and pharmacological inhibition of KDM1A cause organoid growth retardation. Further, it is shown that most of KDM1A cancer-supporting functions center on repression of N-myc downstream regulates gene-1 (NDRG1). De-repression of NDRG1 by KDM1A inhibitors (KDM1Ai) causes inhibition of Wnt signaling and a strong G1 cell cycle arrest. Finally, by profiling 20 GC PDOs, it is shown that NDRG1 upregulation predicts KDM1Ai response with 100% sensitivity and 82% specificity in the tested cohort. Thus, this work pioneers the use of negative selection CRISPR screens in patient-derived organoids, identifies a marker of KDM1Ai response, and accordingly a cohort of patients who may benefit from such therapy.

Prognostic value of tumor-associated N1/N2 neutrophil plasticity in patients following radical resection of pancreas ductal adenocarcinoma

BACKGROUND

As an integral part of the tumor microenvironment (TME), tumor-associated neutrophils play a crucial role in tumor development. The objective of this study was to investigate the plasticity of tumor-associated N1 and N2 neutrophils in the TME of pancreatic ductal adenocarcinoma (PDAC), along with its impact on survival and association with immune infiltrations.

METHODS

The primary and validation cohorts including 90 radical resection patients from September 2012 to May 2016 and 29 radical resection patients from September 2018 to October 2019, respectively, with complete survival data, were enrolled. Immunofluorescence staining was used to identify tumor-associated N1 and N2 neutrophils, and the N1/N2 ratio was used to evaluate N1 and N2 plasticity. Thereafter, the association between tumor-associated N1/N2 neutrophil plasticity, clinical features, and immune infiltrations was investigated.

RESULTS

There was a significant increase in tumor-associated N2 neutrophils compared with tumor-associated N1 neutrophils. Low N1/N2 ratios were associated with the poorer differentiation of tumors, easier lymph node metastases, and a higher TNM stage. The median overall survival (OS) and recurrence-free survival (RFS) of the high tumor-associated N1 neutrophil group were significantly longer than those of the low group, while the tumor-associated N2 neutrophils played an opposite role. The multivariable analysis revealed that a high N1/N2 ratio was a significant prognostic indicator for OS and RFS. In addition, tumor-associated N1/N2 neutrophils showed an opposite correlation with tumor-infiltrating CD8⁺ T cells and Tregs.

CONCLUSION

The plasticity of tumor-associated N1/N2 neutrophils was identified as a crucial prognostic indicator that might reflect the TME and immune escape in patients with PDAC. On further investigation and validation, our findings may be used to further stratify patients with varying prognoses to optimize treatment.

The miR-182-5p/NDRG1 Axis Controls Endometrial Receptivity through the NF-κB/ZEB1/E-Cadherin Pathway

Endometrial receptivity is essential for successful pregnancy, and its impairment is a major cause of embryo-implantation failure. MicroRNAs (miRNAs) that regulate epigenetic modifications have been associated with endometrial receptivity. However, the molecular mechanisms whereby miRNAs regulate endometrial receptivity remain unclear. Therefore, we investigated whether miR-182 and its potential targets influence trophoblast cell attachment. miR-182 was expressed at lower levels in the secretory phase than in the proliferative phase of endometrium tissues from fertile donors. However, miR-182 expression was upregulated during the secretory phase in infertile women. Transfecting a synthetic miR-182-5p mimic decreased spheroid attachment of human JAr choriocarcinoma cells and E-cadherin expression (which is important for endometrial receptivity). miR-182-5p also downregulated N-Myc downstream regulated 1 (NDRG1), which was studied further. NDRG1 was upregulated in the secretory phase of the endometrium tissues and induced E-cadherin expression through the nuclear factor-κΒ (NF-κΒ)/zinc finger E-box binding homeobox 1 (ZEB1) signaling pathway. NDRG1-overexpressing or -depleted cells showed altered attachment rates of JAr spheroids. Collectively, our findings indicate that miR-182-5p-mediated NDRG1 downregulation impaired embryo implantation by upregulating the NF-κΒ/ZEB1/E-cadherin pathway. Hence, miR-182-5p is a potential biomarker for negative selection in endometrial receptivity and a therapeutic target for successful embryo implantation.

Thiosemicarbazones reprogram pancreatic cancer bidirectional oncogenic signaling between cancer cells and stellate cells to suppress desmoplasia

Standard treatments have shown dismal activity against pancreatic cancer (PC), due in part to the development of a dense stroma (desmoplasia). This perspective discusses the development of the di-2-pyridylketone thiosemicarbazones that overcomes bidirectional oncogenic signaling between PC cells and pancreatic stellate cells (PSCs), which is critical for desmoplasia development. This activity is induced by the up-regulation of the metastasis suppressor, N-myc downstream-regulated gene-1 (NDRG1), which inhibits oncogenic signaling via HGF, IGF-1 and Sonic Hedgehog pathway. More recent studies have deciphered additional pathways including those mediated by Wnt and tenascin C that are secreted by PSCs to activate β-catenin and YAP/TAZ signaling in PC cells. Suppression of bidirectional signaling between cell types presents a unique therapeutic opportunity.

Novel Insight Into Nutritional Regulation in Enhancement of Immune Status and Mediation of Inflammation Dynamics Integrated Study In Vivo and In Vitro of Teleost Grass Carp (Ctenopharyngodon idella): Administration of Threonine

This study aims to investigate the effects of threonine (Thr) on immunoregulation in vivo and in vitro of teleost grass carp (Ctenopharyngodon idella). Juveniles (9.53 ± 0.02 g) were reared for 8 weeks with respective Thr diet (3.99, 7.70, 10.72, 14.10, 17.96, and 21.66 g/kg) and then challenged with Aeromonas hydrophila for in vivo study. Macrophages isolated from head kidney were treated in vitro for 48 h with L-Thr (0, 0.5, 1.0, 2.0, 4.0, and 8.0 mM) after 6 h of lipopolysaccharide induction. The results showed that, compared with Thr deficiency (3.99 g/kg), the optimal dietary Thr (14.10g/kg) affected the immunocyte activation in the head kidney (HK) and spleen (SP) by downregulating the mRNA expressions of MHC-II and upregulating CD4 (not CD8), and it mediated the innate immune by enhancing the activities of lysozyme (LZ), acid phosphatase content of complement 3 (C3) and C4, increasing the mRNA abundances of hepcidin, liver expressed antimicrobial peptide-2A (LEAP-2A), LEAP-2B, β-defensin1, downregulating tumor necrosis factor α (TNF-α), IL-6, IL-1β, IL-12p35, IL-12p40, IL-17AF1, and IL-17D partly by attenuating RORγ1 transcriptional factor and nuclear factor kappa B p65 (NF-κBp65) signaling cascades [IKKβ/IκBα/NF-κBp65] and upregulating transforming growth factor β1 (TGF-β1), IL-4/13A, -4/13B, IL-10, and IL-22 partly by GATA-3. Besides these, the optimal dietary Thr regulated the adaptive immune by upregulating the mRNAs of immunoglobulin M (IgM) and IgZ (not IgD). Moreover, 2 mM Thr downregulated in vitro the mRNA abundances of colony stimulating factor-1, inducible nitric oxide synthase, mannose receptor 1, matrix metalloproteinase2 (MMP-2), and MMP-9 significantly (P < 0.05), indicating that Thr could attenuate the M1-type macrophages’ activation. Moreover, L-Thr downregulated the mRNA transcripts of TNF-α, IL-6, and IL-1β associated with impairing the SOCS1/STAT1 signaling and upregulated IL-10 and TGF-β1 partly by accentuating the SOCS3/STAT3 pathway. The above-mentioned observations suggested that Thr improved the immune status in the immune organs of fish by enhancing the immune defense and mediating the inflammation process. Finally, based on the immune indices of LZ activity in HK and C3 content in SP, the optimal Thr for immune enhancement in juvenile grass carp (9.53–53.43 g) was determined to be 15.70 g/kg diet (4.85 g/100 g protein) and 14.49 g/kg diet (4.47 g/100 g protein), respectively.

Targeting Wnt/tenascin C-mediated cross talk between pancreatic cancer cells and stellate cells via activation of the metastasis suppressor NDRG1

A major barrier to successful pancreatic cancer (PC) treatment is the surrounding stroma, which secretes growth factors/cytokines that promote PC progression. Wnt and tenascin C (TnC) are key ligands secreted by stromal pancreatic stellate cells (PSCs) that then act on PC cells in a paracrine manner to activate the oncogenic β-catenin and YAP/TAZ signaling pathways. Therefore, therapies targeting oncogenic Wnt/TnC cross talk between PC cells and PSCs constitute a promising new therapeutic approach for PC treatment. The metastasis suppressor N-myc downstream-regulated gene-1 (NDRG1) inhibits tumor progression and metastasis in numerous cancers, including PC. We demonstrate herein that targeting NDRG1 using the clinically trialed anticancer agent di-2-pyridylketone-4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC) inhibited Wnt/TnC-mediated interactions between PC cells and the surrounding PSCs. Mechanistically, NDRG1 and DpC markedly inhibit secretion of Wnt3a and TnC by PSCs, while also attenuating Wnt/β-catenin and YAP/TAZ activation and downstream signaling in PC cells. This antioncogenic activity was mediated by direct inhibition of β-catenin and YAP/TAZ nuclear localization and by increasing the Wnt inhibitor, DKK1. Expression of NDRG1 also inhibited transforming growth factor (TGF)-β secretion by PC cells, a key mechanism by which PC cells activate PSCs. Using an in vivo orthotopic PC mouse model, we show DpC downregulated β-catenin, TnC, and YAP/TAZ, while potently increasing NDRG1 expression in PC tumors. We conclude that NDRG1 and DpC inhibit Wnt/TnC-mediated interactions between PC cells and PSCs. These results further illuminate the antioncogenic mechanism of NDRG1 and the potential of targeting this metastasis suppressor to overcome the oncogenic effects of the PC-PSC interaction.

Cell Lineage Infidelity in PDAC Progression and Therapy Resistance

Infidelity to cell fate occurs when differentiated cells lose their original identity and either revert to a more multipotent state or transdifferentiate into a different cell type, either within the same embryonic lineage or in an entirely different one. Whilst in certain circumstances, such as in wound repair, this process is beneficial, it can be hijacked by cancer cells to drive disease initiation and progression. Cell phenotype switching has been shown to also serve as a mechanism of drug resistance in some epithelial cancers. In pancreatic ductal adenocarcinoma (PDAC), the role of lineage infidelity and phenotype switching is still unclear. Two consensus molecular subtypes of PDAC have been proposed that mainly reflect the existence of cell lineages with different degrees of fidelity to pancreatic endodermal precursors. Indeed, the classical subtype of PDAC is characterised by the expression of endodermal lineage specifying transcription factors, while the more aggressive basal-like/squamous subtype is defined by epigenetic downregulation of endodermal genes and alterations in chromatin modifiers. Here, we summarise the current knowledge of mechanisms (genetic and epigenetic) of cell fate switching in PDAC and discuss how pancreatic organoids might help increase our understanding of both cell-intrinsic and cell-extrinsic factors governing lineage infidelity during the distinct phases of PDAC evolution.

The Metastasis Suppressor NDRG1 Directly Regulates Androgen Receptor Signaling in Prostate Cancer

N-myc-downregulated gene 1 (NDRG1) has potent anticancer effects and inhibits cell growth, survival, metastasis, and angiogenesis. Previous studies suggested that NDRG1 is linked to the androgen signaling network, but this mechanistic relationship is unclear. Considering the crucial role of the androgen receptor (AR) in prostate cancer (PCa) progression, here we examined for the first time the effect of NDRG1 on AR expression, activation, and downstream signaling in LNCaP, 22Rv1, and C4-2B PCa cell types. We demonstrate that NDRG1 effectively promotes interaction of AR with the chaperone HSP90, which in turn stabilizes the AR while decreasing its androgen-mediated activation. The expression of NDRG1 suppressed: (1) AR activation, as measured by p-AR^Ser213 and p-AR^Ser81; (2) expression of a major AR transcriptional target, prostate-specific antigen (PSA); and (3) AR transcriptional activity, probably via inhibiting the c-Jun-AR interaction by reducing c-Jun phosphorylation (p-c-Jun^Ser63). NDRG1 was also demonstrated to inhibit multiple key molecules involved in androgen-dependent and -independent signaling (namely EGFR, HER2, HER3, PI3K, STAT3, and NF-κB), which promote the development of castration-resistant prostate cancer. We also identified the cysteine-rich secretory protein/antigen 5/pathogenesis related-1 (CAP) domain of NDRG1 as vital for inhibition of AR activity. Examining NDRG1 and p-NDRG1 in PCa patient specimens revealed a significant negative correlation between NDRG1 and PSA levels in prostatectomy patients that went on to develop metastasis. These results highlight a vital role for NDRG1 in androgen signaling and its potential as a key therapeutic target and biomarker in PCa.

The Relationship of Glutathione-S-Transferase and Multi-Drug Resistance-Related Protein 1 in Nitric Oxide (NO) Transport and Storage

Nitric oxide is a diatomic gas that has traditionally been viewed, particularly in the context of chemical fields, as a toxic, pungent gas that is the product of ammonia oxidation. However, nitric oxide has been associated with many biological roles including cell signaling, macrophage cytotoxicity, and vasodilation. More recently, a model for nitric oxide trafficking has been proposed where nitric oxide is regulated in the form of dinitrosyl-dithiol-iron-complexes, which are much less toxic and have a significantly greater half-life than free nitric oxide. Our laboratory has previously examined this hypothesis in tumor cells and has demonstrated that dinitrosyl-dithiol-iron-complexes are transported and stored by multi-drug resistance-related protein 1 and glutathione-S-transferase P1. A crystal structure of a dinitrosyl-dithiol-iron complex with glutathione-S-transferase P1 has been solved that demonstrates that a tyrosine residue in glutathione-S-transferase P1 is responsible for binding dinitrosyl-dithiol-iron-complexes. Considering the roles of nitric oxide in vasodilation and many other processes, a physiological model of nitric oxide transport and storage would be valuable in understanding nitric oxide physiology and pathophysiology.

The Oncogenic Signaling Disruptor, NDRG1: Molecular and Cellular Mechanisms of Activity

NDRG1 is an oncogenic signaling disruptor that plays a key role in multiple cancers, including aggressive pancreatic tumors. Recent studies have indicated a role for NDRG1 in the inhibition of multiple tyrosine kinases, including EGFR, c-Met, HER2 and HER3, etc. The mechanism of activity of NDRG1 remains unclear, but to impart some of its functions, NDRG1 binds directly to key effector molecules that play roles in tumor suppression, e.g., MIG6. More recent studies indicate that NDRG1s-inducing drugs, such as novel di-2-pyridylketone thiosemicarbazones, not only inhibit tumor growth and metastasis but also fibrous desmoplasia, which leads to chemotherapeutic resistance. The Casitas B-lineage lymphoma (c-Cbl) protein may be regulated by NDRG1, and is a crucial E3 ligase that regulates various protein tyrosine and receptor tyrosine kinases, primarily via ubiquitination. The c-Cbl protein can act as a tumor suppressor by promoting the degradation of receptor tyrosine kinases. In contrast, c-Cbl can also promote tumor development by acting as a docking protein to mediate the oncogenic c-Met/Crk/JNK and PI3K/AKT pathways. This review hypothesizes that NDRG1 could inhibit the oncogenic function of c-Cbl, which may be another mechanism of its tumor-suppressive effects.

Neutrophil in the Pancreatic Tumor Microenvironment

Pancreatic ductal adenocarcinoma (PDAC) is a malignancy with a poor prognosis and low survival rates. PDAC is characterized by a fibroinflammatory tumor microenvironment enriched by abundant fibroblasts and a variety of immune cells, contributing to its aggressiveness. Neutrophils are essential infiltrating immune cells in the PDAC microenvironment. Recent studies have identified several cellular mechanisms by which neutrophils are recruited to tumor lesion and promote tumorigenesis. This review summarizes the current understanding of the interplay between neutrophils, tumor cells, and other components in the PDAC tumor microenvironment. The prognosis and therapeutic implications of neutrophils in PDAC are also discussed.

Chronic Pancreatitis and the Development of Pancreatic Cancer

Pancreatitis is a fibro-inflammatory disorder of the pancreas that can occur acutely or chronically as a result of the activation of digestive enzymes that damage pancreatic cells, which promotes inflammation. Chronic pancreatitis with persistent fibro-inflammation of the pancreas progresses to pancreatic cancer, which is the fourth leading cause of cancer deaths across the globe. Pancreatic cancer involves cross-talk of inflammatory, proliferative, migratory, and fibrotic mechanisms. In this review, we discuss the role of cytokines in the inflammatory cell storm in pancreatitis and pancreatic cancer and their role in the activation of SDF1α/CXCR4, SOCS3, inflammasome, and NF-κB signaling. The aberrant immune reactions contribute to pathological damage of acinar and ductal cells, and the activation of pancreatic stellate cells to a myofibroblast-like phenotype. We summarize several aspects involved in the promotion of pancreatic cancer by inflammation and include a number of regulatory molecules that inhibit that process.

Metastasis Suppressor Genes in Pancreatic Cancer: An Update

ABSTRACT

Pancreatic cancer, especially pancreatic ductal adenocarcinoma (PDAC), has for long remained a deadly form of cancer characterized by high mortality rates resulting from metastasis to multiple organs. Several factors, including the late manifestation of the disease, partly amplified by lack of efficient screening methods, have hampered the drive to design an effective therapeutic strategy to treat this deadly cancer. Understanding the biology of PDAC progression and identifying critical genes regulating these processes are essential to overcome the barriers toward effective treatment. Metastasis suppressor genes have been shown to inhibit multiple steps in the metastatic cascade without affecting primary tumor formation and are considered to hold promise for treating metastatic cancers. In this review, we catalog the bona fide metastasis suppressor genes reported in PDAC and discuss their known mechanism of action.

Breaking the cycle: Targeting of NDRG1 to inhibit bi-directional oncogenic cross-talk between pancreatic cancer and stroma

Pancreatic cancer (PaCa) is characterized by dense stroma that hinders treatment efficacy, with pancreatic stellate cells (PSCs) being a major contributor to this stromal barrier and PaCa progression. Activated PSCs release hepatocyte growth factor (HGF) and insulin-like growth factor (IGF-1) that induce PaCa proliferation, metastasis and resistance to chemotherapy. We demonstrate for the first time that the metastasis suppressor, N-myc downstream regulated gene 1 (NDRG1), is a potent inhibitor of the PaCa-PSC cross-talk, leading to inhibition of HGF and IGF-1 signaling. NDRG1 also potently reduced the key driver of PaCa metastasis, namely GLI1, leading to reduced PSC-mediated cell migration. The novel clinically trialed anticancer agent, di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC), which upregulates NDRG1, potently de-sensitized PaCa cells to ligands secreted by activated PSCs. DpC and NDRG1 also inhibited the PaCa-mediated activation of PSCs via inhibition of sonic hedgehog (SHH) signaling. In vivo, DpC markedly reduced PaCa tumor growth and metastasis more avidly than the standard chemotherapy for this disease, gemcitabine. Uniquely, DpC was selectively cytotoxic against PaCa cells, while "re-programming" PSCs to an inactive state, decreasing collagen deposition and desmoplasia. Thus, targeting NDRG1 can effectively break the oncogenic cycle of PaCa-PSC bi-directional cross-talk to overcome PaCa desmoplasia and improve therapeutic outcomes.

Identification of Seven-Gene Hypoxia Signature for Predicting Overall Survival of Hepatocellular Carcinoma

Background

Hepatocellular carcinoma (HCC) is ranked fifth among the most common cancer worldwide. Hypoxia can induce tumor growth, but the relationship with HCC prognosis remains unclear. Our study aims to construct a hypoxia-related multigene model to predict the prognosis of HCC.

Methods

RNA-seq expression data and related clinical information were download from TCGA database and ICGC database, respectively. Univariate/multivariate Cox regression analysis was used to construct prognostic models. KM curve analysis, and ROC curve were used to evaluate the prognostic models, which were further verified in the clinical traits and ICGC database. GSEA analyzed pathway enrichment in high-risk groups. Nomogram was constructed to predict the personalized treatment of patients. Finally, real-time fluorescence quantitative PCR (RT-qPCR) was used to detect the expressions of KDELR3 and SCARB1 in normal hepatocytes and 4 HCC cells. The expressions of SCARB1 in hepatocellular carcinoma tissue in 46 patients were detected by immunohistochemistry, and the correlation between its expressions and disease free survival of patient was calculated.

Results

Through a series of analyses, seven prognostic markers related to HCC survival were constructed. HCC patients were divided into the high and low risk group, and the results of KM curve showed that there was a significant difference between the two groups. Stratified analysis, found that there were significant differences in risk values of different ages, genders, stages and grades, which could be used as independent predictors. In addition, we assessed the risk value in the clinical traits analysis and found that it could accelerate the progression of cancer, while the results of GSEA enrichment analysis showed that the high-risk group patients were mainly distributed in the cell cycle and other pathways. Then, Nomogram was constructed to predict the overall survival of patients. Finally, RT-qPCR showed that KDELR3 and SCARB1 were highly expressed in HepG2 and L02, respectively. Results of IHC staining showed that SCARB1 was highly expressed in cancer tissues compared to adjacent normal liver tissues and its expression was related to hepatocellular carcinoma differentiation status. The Kaplan-Meier survival showed a poor percent survival in the SCARB1 high group compared to that in the SCARB1 low group.

Conclusion

This study provides a potential diagnostic indicator for HCC patients, and help clinicians to deepen the comprehension in HCC pathogenesis so as to make personalized medical decisions.

iTRAQ-Based Quantitative Proteomic Analysis of Intestines in Murine Polymicrobial Sepsis with Hydrogen Gas Treatment

Objective

Sepsis-associated intestinal injury has a higher morbidity and mortality in patients with sepsis, but there is still no effective treatment. Our research team has proven that inhaling 2% hydrogen gas (H₂) can effectively improve sepsis and related organ damage, but the specific molecular mechanism of its role is not clear. In this study, isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomics analysis was used for studying the effect of H₂ on intestinal injury in sepsis.

Methods

Male C57BL/6J mice were used to prepare a sepsis model by cecal ligation and puncture (CLP). The 7-day survival rates of mice were measured. 4-kd fluorescein isothiocyanate-conjugated Dextran (FITC-dextran) blood concentration measurement, combined with hematoxylin-eosinstain (HE) staining and Western blotting, was used to study the effect of H₂ on sepsis-related intestinal damage. iTRAQ-based liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis was used for studying the proteomics associated with H₂ for the treatment of intestinal injury.

Results

H₂ can significantly improve the 7-day survival rates of sepsis mice. The load of blood and peritoneal lavage bacteria was increased, and H₂ treatment can significantly reduce it. CLP mice had significant intestinal damage, and inhalation of 2% hydrogen could significantly reduce this damage. All 4194 proteins were quantified, of which 199 differentially expressed proteins were associated with the positive effect of H₂ on sepsis. Functional enrichment analysis indicated that H₂ may reduce intestinal injury in septic mice through the effects of thyroid hormone synthesis and nitrogen metabolism signaling pathway. Western blot showed that H₂ was reduced by down-regulating the expressions of deleted in malignant brain tumors 1 protein (DMBT1), insulin receptor substrate 2 (IRS2), N-myc downregulated gene 1 (NDRG1) and serum amyloid A-1 protein (SAA1) intestinal damage in sepsis mice.

Conclusion

A total of 199 differential proteins were related with H₂ in the intestinal protection of sepsis. H₂-related differential proteins were notably enriched in the following signaling pathways, including thyroid hormone synthesis signaling pathway, nitrogen metabolism signaling pathways, digestion and absorption signaling pathways (vitamins, proteins and fats). H₂ reduced intestinal injury in septic mice by down-regulating the expressions of SAA1, NDRG1, DMBT1 and IRS2.

Pharmacological targeting and the diverse functions of the metastasis suppressor, NDRG1, in cancer

N-myc downstream regulated gene-1 (NDRG1) is a potent metastasis suppressor that is regulated by hypoxia, metal ions including iron, the free radical nitric oxide (NO^.), and various stress stimuli. This intriguing molecule exhibits diverse functions in cancer, inhibiting epithelial-mesenchymal transition (EMT), cell migration and angiogenesis by modulation of a plethora of oncogenes via cellular signaling. Thus, pharmacological targeting of NDRG1 signaling in cancer is a promising therapeutic strategy. Of note, novel anti-tumor agents of the di-2-pyridylketone thiosemicarbazone series, which exert the "double punch" mechanism by binding metal ions to form redox-active complexes, have been demonstrated to markedly up-regulate NDRG1 expression in cancer cells. This review describes the mechanisms underlying NDRG1 modulation by the thiosemicarbazones and the diverse effects NDRG1 exerts in cancer. As a major induction mechanism, iron depletion appears critical, with NO^. also inducing NDRG1 through its ability to bind iron and generate dinitrosyl-dithiol iron complexes, which are then effluxed from cells. Apart from its potent anti-metastatic role, several studies have reported a pro-oncogenic role of NDRG1 in a number of cancer-types. Hence, it has been suggested that NDRG1 plays pleiotropic roles depending on the cancer-type. The molecular mechanism(s) underlying NDRG1 pleiotropy remain elusive, but are linked to differential regulation of WNT signaling and potentially differential interaction with the tumor suppressor, PTEN. This review discusses NDRG1 induction mechanisms by metal ions and NO^. and both the anti- and possible pro-oncogenic functions of NDRG1 in multiple cancer-types and compares the opposite effects this protein exerts on cancer progression.

LINC01419 promotes cell proliferation and metastasis in hepatocellular carcinoma by enhancing NDRG1 promoter activity

PURPOSE

Emerging evidence indicates that dysfunction of long non-coding RNAs (lncRNAs) plays an essential role in the initiation and progression of hepatocellular carcinoma (HCC). In this study we investigated the potential roles and molecular mechanisms involving LINC01419 in HCC.

METHODS

The expression of LINC01419 in 40 pairs of HCC/normal tissues and 6 HCC cell lines was detected by qRT-PCR. MTS, EdU, colony formation, scratch wound-healing and transwell assays were performed to assess the role of LINC01419 in HCC cell (SMMC7721 and SK-Hep1) proliferation, migration and invasion in vitro. Artificial modulation of LINC01419 (up- and downregulation) was performed to explore the role of LINC01419 in tumor growth and metastasis in vivo. Interaction of LINC01419 with NDRG1 was assessed using qRT-PCR, RNA sequencing, Western blotting and immunohistochemistry. Physical interaction of LINC01419 with the NDRG1 promoter was assessed using a dual-luciferase reporter assay.

RESULTS

We observed LINC01419 overexpression in primary HCC tissues and HCC cell lines and that this overexpression positively correlated with large tumor size, increased vascular invasion and advanced TNM stage in 40 HCC patients. Exogenous LINC01419 expression significantly promoted HCC cell proliferation, migration and invasion in vitro, as well as tumorigenesis and metastasis in vivo. Conversely, we found that LINC01419 expression knockdown elicited opposite effects. Mechanistic investigations revealed that LINC01419 exerted its biological effects by regulating NDRG1. A dual-luciferase reporter assay revealed that LINC01419 interacts with a specific region within the NDRG1 promoter, resulting in its activation.

CONCLUSIONS

From our data we conclude that LINC01419 acts clinically, functionally and mechanistically oncogenic in HCC. LINC01419 may, therefore, serve as a promising prognostic indicator and therapeutic target for HCC.

Increased NDRG1 expression suppresses angiogenesis via PI3K/AKT pathway in human placental cells

OBJECTIVE

To observe whether and how N-myc downstream-regulated gene 1 (NDRG1) regulates placental angiogenesis via JEG-3 placental-derived cells.

METHODS

Expression of NDRG1 in stably transfected JEG-3 cells was detected using western blot and real-time quantitative polymerase chain reaction. Angiogenesis was examined by tube formation assay. The levels of placental growth factor (PLGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) were examined using enzyme-linked immunosorbent assay. The expression of vascular endothelial growth factor (VEGF), PI3K, and AKT was examined by western blot. The relationship between PI3K and NDRG1 was detected by co-immunoprecipitation.

RESULTS

NDRG1 was significantly down-regulated at both the mRNA and protein level by lentivirus (Lv)-NDRG1-shRNA (P < 0.001), whereas it was significantly up-regulated by Lv-NDRG1 (P < 0.001). NDRG1 knockdown significantly increase the expression of PLGF and VEGF in JEG-3 cells (P < 0.001), while NDRG1 knockdown significantly reduced the secretion of sFlt-1 (P < 0.001). NDRG1 was specific bound to PI3K, and NDRG1 knockdown significantly up-regulated the expressions of PI3K and AKT in JEG-3 cells (P < 0.001).

CONCLUSION

NDRG1 suppresses angiogenesis in preeclampsia, and the PI3K/AKT signaling pathway may be involved in the regulation of angiogenesis by NDRG1.

The metastasis suppressor, NDRG1, attenuates oncogenic TGF-β and NF-κB signaling to enhance membrane E-cadherin expression in pancreatic cancer cells

The metastasis suppressor, N-myc downstream-regulated gene-1 (NDRG1), plays multifaceted roles in inhibiting oncogenic signaling and can suppress the epithelial mesenchymal transition (EMT), a key step in metastasis. In this investigation, NDRG1 inhibited the oncogenic effects of transforming growth factor-β (TGF-β) in PANC-1 pancreatic cancer cells, promoting expression and co-localization of E-cadherin and β-catenin at the cell membrane. A similar effect of NDRG1 at supporting E-cadherin and β-catenin co-localization at the cell membrane was also demonstrated for HT-29 colon and CFPAC-1 pancreatic cancer cells. The increase in E-cadherin in PANC-1 cells in response to NDRG1 was mediated by the reduction of three transcriptional repressors of E-cadherin, namely SNAIL, SLUG and ZEB1. To dissect the mechanisms how NDRG1 inhibits nuclear SNAIL, SLUG and ZEB1, we assessed involvement of the nuclear factor-κB (NF-κB) pathway, as its aberrant activation contributes to the EMT. Interestingly, NDRG1 comprehensively inhibited oncogenic NF-κB signaling at multiple sites in this pathway, suppressing NEMO, Iĸĸα and IĸBα expression, as well as reducing the activating phosphorylation of Iĸĸα/β and IĸBα. NDRG1 also reduced the levels, nuclear co-localization and DNA-binding activity of NF-κB p65. Further, Iĸĸα, which integrates NF-κB and TGF-β signaling to upregulate ZEB1, SNAIL and SLUG, was identified as an NDRG1 target. Considering this, therapies targeting NDRG1 could be a new strategy to inhibit metastasis, and as such, we examined novel anticancer agents, namely di-2-pyridylketone thiosemicarbazones, which upregulate NDRG1. These agents downregulated SNAIL, SLUG and ZEB1 in vitro and in vivo using a PANC-1 tumor xenograft model, demonstrating their marked potential.

NDRG1 activates VEGF-A-induced angiogenesis through PLCγ1/ERK signaling in mouse vascular endothelial cells

Many diseases, including cancer, have been associated with impaired regulation of angiogenesis, of which vascular endothelial growth factor (VEGF)-A is a key regulator. Here, we test the contribution of N-myc downstream regulated gene 1 (NDRG1) to VEGF-A-induced angiogenesis in vascular endothelial cells (ECs). Ndrg1^−/− mice exhibit impaired VEGF-A-induced angiogenesis in corneas. Tumor angiogenesis induced by cancer cells that express high levels of VEGF-A was also reduced in a mouse dorsal air sac assay. Furthermore, NDRG1 deficiency in ECs prevented angiogenic sprouting from the aorta and the activation of phospholipase Cγ1 (PLCγ1) and ERK1/2 by VEGF-A without affecting the expression and function of VEGFR2. Finally, we show that NDRG1 formed a complex with PLCγ1 through its phosphorylation sites, and the inhibition of PLCγ1 dramatically suppressed VEGF-A-induced angiogenesis in the mouse cornea, suggesting an essential role of NDRG1 in VEGF-A-induced angiogenesis through PLCγ1 signaling.

Kosuke Watari et al. show that N-myc downstream-regulated gene 1 (NDRG1) stimulates new blood vessel formation that is induced by VEGF-A, using Ndrg1 knockout mice. They find that PLCγ1/ERK signaling mediates this regulation, providing mechanistic insights into how vascular endothelial cells form new vessels.

Bidirectional Regulation between NDRG1 and GSK3β Controls Tumor Growth and Is Targeted by Differentiation Inducing Factor-1 in Glioblastoma

The development of potent and selective therapeutic approaches to glioblastoma (GBM), one of the most aggressive primary brain tumors, requires identification of molecular pathways that critically regulate the survival and proliferation of GBM. Previous studies have reported that deregulated expression of N-myc downstream regulated gene 1 (NDRG1) affects tumor growth and clinical outcomes of patients with various types of cancer including glioma. Here, we show that high level expression of NDRG1 in tumors significantly correlated with better prognosis of patients with GBM. Loss of NDRG1 in GBM cells upregulated GSK3β levels and promoted cell proliferation, which was reversed by selective inhibitors of GSK3β. In contrast, NDRG1 overexpression suppressed growth of GBM cells by decreasing GSK3β levels via proteasomal degradation and by suppressing AKT and S6 cell growth signaling, as well as cell-cycle signaling pathways. Conversely, GSK3β phosphorylated serine and threonine sites in the C-terminal domain of NDRG1 and limited the protein stability of NDRG1. Furthermore, treatment with differentiation inducing factor-1, a small molecule derived from Dictyostelium discoideum, enhanced NDRG1 expression, decreased GSK3β expression, and exerted marked NDRG1-dependent antitumor effects in vitro and in vivo. Taken together, this study revealed a novel molecular mechanism by which NDRG1 inhibits GBM proliferation and progression. Our study thus identifies the NDRG1/GSK3β signaling pathway as a key growth regulatory program in GBM, and suggests enhancing NDRG1 expression in GBM as a potent strategy toward the development of anti-GBM therapeutics. SIGNIFICANCE: This study identifies NDRG1 as a potent and endogenous suppressor of glioblastoma cell growth, suggesting the clinical benefits of NDRG1-targeted therapeutics against glioblastoma.

NF-κB Dependent Chemokine Signaling in Pancreatic Cancer

Pancreatic cancer is one of the carcinomas with the worst prognoses, as shown by its five-year survival rate of 9%. Although there have been new therapeutic innovations, the effectiveness of these therapies is still limited, resulting in pancreatic ductal adenocarcinoma (PDAC) becoming the second leading cause of cancer-related death in 2020 in the US. In addition to tumor cell intrinsic resistance mechanisms, this disease exhibits a complex stroma consisting of fibroblasts, immune cells, neuronal and vascular cells, along with extracellular matrix, all conferring therapeutic resistance by several mechanisms. The NF-κB pathway is involved in both the tumor cell-intrinsic and microenvironment-mediated therapeutic resistance by regulating the transcription of a plethora of target genes. These genes are involved in nearly all scenarios described as the hallmarks of cancer. In addition to classical regulators of apoptosis, NF-κB regulates the expression of chemokines and their receptors, both in the tumor cells and in cells of the microenvironment. These chemokines mediate autocrine and paracrine loops among tumor cells but also cross-signaling between tumor cells and the stroma. In this review, we will focus on NF-κB-mediated chemokine signaling, with an emphasis on therapy resistance in pancreatic cancer.

Cx43 phosphorylation-mediated effects on ERK and Akt protect against ischemia reperfusion injury and alter the stability of the stress-inducible protein NDRG1

Gap junctions contain intercellular channels that enable intercellular communication of small molecules while also serving as a signaling scaffold. Connexins, the proteins that form gap junctions in vertebrates, are highly regulated and typically have short (<2 h) half-lives. Connexin43 (Cx43), the predominate connexin in the myocardium and epithelial tissues, is phosphorylated on more than a dozen serine residues and interacts with a variety of protein kinases. These interactions regulate Cx43 and gap junction formation and stability. Casein kinase 1 (CK1)-mediated phosphorylation of Cx43 promotes gap junction assembly. Using murine knock-in technology and quantitative PCR, immunoblotting, and immunoprecipitation assays, we show here that mutation of the CK1 phosphorylation sites in Cx43 reduces the levels of total Cx43 in the myocardium and increases Cx43 phosphorylation on sites phosphorylated by extracellular signal-regulated kinase (ERK). In aged myocardium, we found that, compared with WT Cx43, mutant Cx43 expression increases ERK activation, phosphorylation of Akt substrates, and protection from ischemia-induced injury. Our findings also uncovered that Cx43 interacts with the hypoxia-inducible protein N-Myc downstream-regulated gene 1 protein (NDRG1) and that Cx43 phosphorylation status controls this interaction and dramatically affects NDRG1 stability. We propose that, in addition to altering gap junction stability, Cx43 phosphorylation directly and dynamically regulates cellular signaling through ERK and Akt in response to ischemic injury. We conclude that gap junction-dependent NDRG1 regulation might explain some cellular responses to hypoxia.

Proteome and Phosphoproteome Analysis in TNF Long Term-Exposed Primary Human Monocytes

To better understand the inflammation-associated mechanisms modulating and terminating tumor necrosis factor (TNF-)induced signal transduction and the development of TNF tolerance, we analyzed both the proteome and the phosphoproteome in TNF long term-incubated (i.e., 48 h) primary human monocytes using liquid chromatography-mass spectrometry. Our analyses revealed the presence of a defined set of proteins characterized by reproducible changes in expression and phosphorylation patterns in long term TNF-treated samples. In total, 148 proteins and 569 phosphopeptides were significantly regulated (103 proteins increased, 45 proteins decreased; 377 peptides with increased and 192 peptides with decreased phosphorylation). A variety of these proteins are associated with the non-canonical nuclear factor κB (NF-κB) pathway (nuclear factor κB (NFKB) 2, v-rel reticuloendotheliosis viral oncogene homolog (REL) B, indolamin-2,3-dioxygenase (IDO), kynureninase (KYNU)) or involved in the negative regulation of the canonical NF-κB system. Within the phosphopeptides, binding motifs for specific kinases were identified. Glycogen synthase kinase (GSK) 3 proved to be a promising candidate, since it targets NF-κB inhibiting factors, such as CCAAT/enhancer binding protein (C/EBP) β. Our experiments demonstrate that both proteome and phosphoproteome analysis can be effectively applied to study protein/phosphorylation patterns of primary monocytes. These results provide new regulatory candidates and evidence for a complex network of specific but synergistically acting/cooperating mechanisms enabling the affected cells to resist sustained TNF exposure and resulting in the resolution of inflammation.

Targeting Oncogenic Nuclear Factor Kappa B Signaling with Redox-Active Agents for Cancer Treatment

SIGNIFICANCE

Nuclear factor kappa B (NF-κB) signaling is essential under physiologically relevant conditions. However, aberrant activation of this pathway plays a pertinent role in tumorigenesis and contributes to resistance. Recent Advances: The importance of the NF-κB pathway means that its targeting must be specific to avoid side effects. For many currently used therapeutics and those under development, the ability to generate reactive oxygen species (ROS) is a promising strategy.

CRITICAL ISSUES

As cancer cells exhibit greater ROS levels than their normal counterparts, they are more sensitive to additional ROS, which may be a potential therapeutic niche. It is known that ROS are involved in (i) the activation of NF-κB signaling, when in sublethal amounts; and (ii) high levels induce cytotoxicity resulting in apoptosis. Indeed, ROS-induced cytotoxicity is valuable for its capabilities in killing cancer cells, but establishing the potency of ROS for effective inhibition of NF-κB signaling is necessary. Indeed, some cancer treatments, currently used, activate NF-κB and may stimulate oncogenesis and confer resistance.

FUTURE DIRECTIONS

Thus, combinatorial approaches using ROS-generating agents alongside conventional therapeutics may prove an effective tactic to reduce NF-κB activity to kill cancer cells. One strategy is the use of thiosemicarbazones, which form redox-active metal complexes that generate high ROS levels to deliver potent antitumor activity. These agents also upregulate the metastasis suppressor, N-myc downstream regulated gene 1 (NDRG1), which functions as an NF-κB signaling inhibitor. It is proposed that targeting NF-κB signaling may proffer a new therapeutic niche to improve the efficacy of anticancer regimens.

Dietary conjugated linoleic acid modulates morphology, selective immune parameters, and gene expressions in the intestine of grass carp

Conjugated linoleic acid (CLA) has been shown to exhibit anti-inflammatory properties in the intestine in mammals. However, the effect of CLA on intestinal immune response in fish is still unknown. Therefore, a 65-day growth trial was conducted to investigate the effects of dietary conjugated linoleic acid (CLA) on morphology, selective immune parameters, and gene expressions in the intestine of grass carp. Seven isonitrogenous and isolipidic diets were formulated as follows: 0 (control), 0.5 (CLA0.5), 1 (CLA1), 1.5 (CLA1.5), 2 (CLA2), 2.5 (CLA2.5), and 3 (CLA3) g CLA per 100g of feed. RESULTS: showed that dietary supplementation of 1.5-3% CLA significantly (P < 0.05) increased the fold and enterocyte heights in the PI and MI of grass carp. Complement 3 (C3) and immunoglobulin M (IgM) contents in three intestinal segments were significantly (P < 0.05) higher in fish fed with CLA1.5 to CLA2.5 diets compared to fish fed the control diet. CLA1.5 to CLA2.5 diets significantly (P < 0.05) increased the mRNA expression levels of anti-inflammatory cytokines (IL-10 and TGFβ1) and significantly (P < 0.05) reduced the mRNA expression levels of pro-inflammatory cytokines (IL-1β, IL-8, and TNF-α) in the PI, MI, and DI. This improved expression of anti-inflammatory cytokines and the inhibited expression of pro-inflammatory cytokines in the intestine of grass carp, might be mediated via TLR4/NF-κB-signaling pathway. Our results suggested that CLA1.5 to CLA2 diets improved intestinal morphology, increased the expression of anti-inflammatory cytokines, and inhibited the expression of pro-inflammatory cytokines in the intestine of grass carp. In conclusion, dietary supplementation of 1.5%-2% CLA show the anti-inflammatory therapeutic potential in the intestine of grass carp. The anti-inflammatory therapeutic potential of CLA might be mediated via TLR4/NF-κB-signaling pathway.

Angiogenesis in pancreatic cancer: current research status and clinical implications

Pancreatic cancer is one of the most lethal malignancies worldwide. Although the standard of care in pancreatic cancer has improved, prognoses for patients remain poor with a 5-year survival rate of < 5%. Angiogenesis, namely, the formation of new blood vessels from pre-existing vessels, is an important event in tumor growth and hematogenous metastasis. It is a dynamic and complex process involving multiple mechanisms and is regulated by various molecules. Inhibition of angiogenesis has been an established therapeutic strategy for many solid tumors. However, clinical outcomes are far from satisfying for pancreatic cancer patients receiving anti-angiogenic therapies. In this review, we summarize the current status of angiogenesis in pancreatic cancer research and explore the reasons for the poor efficacy of anti-angiogenic therapies, aiming to identify some potential therapeutic targets that may enhance the effectiveness of anti-angiogenic treatments.

To die or not to die SGK1-sensitive ORAI/STIM in cell survival

The pore forming Ca²⁺ release activated Ca²⁺ channel (CRAC) isoforms ORAI1-3 and their regulators STIM1,2 accomplish store operated Ca²⁺ entry (SOCE). Activation of SOCE may lead to cytosolic Ca²⁺ oscillations, which in turn support cell proliferation and cell survival. ORAI/STIM and thus SOCE are upregulated by the serum and glucocorticoid inducible kinase SGK1, a kinase under powerful genomic regulation and activated by phosphorylation via the phosphoinositol-3-phosphate pathway. SGK1 enhances ORAI1 abundance partially by phosphorylation of Nedd4-2, an ubiquitin ligase priming the channel protein for degradation. The SGK1-phosphorylated Nedd4-2 binds to the protein 14-3-3 and is thus unable to ubiquinate ORAI1. SGK1 further increases the ORAI1 and STIM1 protein abundance by activating nuclear factor kappa B (NF-κB), a transcription factor upregulating the expression of STIM1 and ORAI1. SGK1-sensitive upregulation of ORAI/STIM and thus SOCE is triggered by a wide variety of hormones and growth factors, as well as several cell stressors including ischemia, radiation, and cell shrinkage. SGK1 dependent upregulation of ORAI/STIM confers survival of tumor cells and thus impacts on growth and therapy resistance of cancer. On the other hand, SGK1-dependent upregulation of ORAI1 and STIM1 may support survival of neurons and impairment of SGK1-dependent ORAI/STIM activity may foster neurodegeneration. Clearly, further experimental effort is needed to define the mechanisms linking SGK1-dependent upregulation of ORAI1 and STIM1 to cell survival and to define the impact of SGK1-dependent upregulation of ORAI1 and STIM1 on malignancy and neurodegenerative disease.

N-myc downstream-regulated gene 1 facilitates influenza A virus replication by suppressing canonical NF-κB signaling

The highly pathogenic avian influenza (HPAI) A/H5N1 virus hijacks host cellular machinery to complete its life cycle; identification of the host factors involved in viral replication may facilitate antiviral drug development. Here, we first characterize a metastasis suppressor, N-myc downstream-regulated gene 1 (NDRG1), and showed that it plays a crucial role in H5N1 viral replication. We found that H5N1 infection upregulated NDRG1 mRNA and protein expression. Overexpression of NDRG1 released approximately 4-fold more virions compared to the control group, whereas knockdown of NDRG1 resulted in a drop in viral RNA and protein production. Further investigation revealed that NDRG1 facilitated HPAI A/H5N1 viral replication by suppressing the canonical NF-κB signaling pathway. Furthermore, our results also showed that the NDRG1 mRNA level was mainly stimulated by M1 and PB1 viral proteins. Overall, our results suggest that NDRG1 plays a positive role in HPAI replication by suppressing the canonical NF-κB signaling pathway.

HER4 promotes cell survival and chemoresistance in osteosarcoma via interaction with NDRG1

Osteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents. The abilities of chemotherapy resistance are major roadblock in the successful treatment of OS. The clarification of mechanism regarding cell survival during OS chemotherapy are important. Here, we examined HER4 expression by immunohistochemistry in a large series of OS tissues, and found HER4 expression correlated with tumor characteristics and patient survival rates. HER4 knockdown by shRNA inhibited OS cell growth and tumorigenesis, and induced cell senescence and apoptosis in vitro and in vivo. We demonstrated that HER4 expression upregulated in the adverse conditions, such as serum starvation and sphere culture. Moreover, HER4 knockdown cells became more sensitive in stressful conditions such as loss of attachment, cytotoxic agents or nutrition insufficiency. Mechanism studies revealed that HER4 interacted with NDRG1, and NDRG1 overexpression could antagonize HER4 knockdown-mediated cell growth and apoptosis in stressed conditions. There was a positive correlation between HER4 and NDRG1 immunoreactivity in OS patients. Together, our present study shows that HER4 and/or NDRG1 might play a critical role for the cell survival and chemo-resistance of OS, and could be used as potential therapeutic targets in OS.

Methionine hydroxy analogue supplementation modulates gill immunological and barrier health status of grass carp (Ctenopharyngodon idella)

This study was conducted to investigate the effects of methionine hydroxy analogue (MHA) on the physical barrier and immune defence in the gill of young grass carp (Ctenopharyngodon idella). A total 630 young grass carp with an average initial weight of 259.70 ± 0.47 g were fed graded levels of MHA (0, 2.4, 4.4, 6.4, 8.5 and 10.5 g/kg diet) and one DL-methionine (DLM) group (6.4 g/kg diet) for 8 weeks. After feeding trial, 15 fish from each treatment were challenged with Flavobacterium columnare. Compared to the basal diet, optimal MHA improved cellular structure integrity of gill via repressing death receptor and mitochondria pathways induced apoptosis, which might be related to the down-regulation of c-Jun-N-terminal kinase mRNA levels (P < .05). Simultaneously, optimal MHA supplementation improved cellular structure integrity of gill via elevating glutathione contents, antioxidant enzymes activities and corresponding isoforms mRNA levels to attenuate oxidative damage, which might be to the up-regulation of NF-E2-related factor 2 mRNA levels and down-regulation of Kelch-like ECH-associating protein 1a mRNA levels (P < .05). Besides, optimal MHA improved intercellular structure integrity of immune organs via up-regulating the mRNA levels of intercellular tight junctions-related genes, which might be owing to the down-regulation of myosin light chain kinase (MLCK) mRNA levels (P < .05). Summarily, MHA could improve the physical barrier of fish gill. In addition, optimal MHA supplementation increased lysozyme (LZ) and acid phosphatase (ACP) activities, complement 3 (C3), C4 and immunoglobulin M contents and up-regulated mRNA levels of liver-expressed antimicrobial peptide 2, hepcidin and β-defensin, suggesting that MHA could enhance antimicrobial ability of fish gill. Meanwhile, optimal MHA supplementation enhanced the immune defence of gill via down-regulating pro-inflammatory cytokines mRNA levels and up-regulated anti-inflammatory cytokines mRNA levels, which might be attributed to the down-regulation of nuclear factor κB p65, c-Rel, IκB kinase β, p38 mitogen activated protein kinase, eIF4E-binding protein1 (4E-BP1) and 4E-BP2 mRNA levels and up-regulation of inhibitor of κBα, ribosomal protein S6 kinase 1 and target of rapamycin mRNA levels (P < .05). In conclusion, the positive effect of MHA on gill health is associated with the improvement of the defence against apoptosis, antioxidant status, tight junctions and immune defence of fish gill. Meanwhile, MHA was superior to DLM on improving the physical barrier of fish gill. For the direction to healthy breeding of young grass carp, the optimal MHA supplementation levels on the premise of 4.01 g/kg methionine basal were estimated by quadratic regression curve, such as 5.49, 6.17 and 6.02 g/kg diet bases on the defence against gill-rot, malondialdehyde content and LZ activity in the gill, respectively.

Role of metastasis-associated lung adenocarcinoma transcript-1 (MALAT-1) in pancreatic cancer

Metastasis-associated lung adenocarcinoma transcript-1 (MALAT-1) is a long non-coding RNA (lncRNA) that is a negative prognostic factor for patients with pancreatic cancer and several other tumors. In this study, we show that knockdown of MALAT-1 in Panc1 and other pancreatic cancer cell lines decreases cell proliferation, survival and migration. We previously observed similar results for the lncRNAs HOTTIP and HOTAIR in Panc1 cells; however, RNAseq comparison of genes regulated by MALAT-1 shows minimal overlap with HOTTIP/HOTAIR-regulated genes. Analysis of changes in gene expression after MALAT-1 knockdown shows that this lncRNA represses several tumor suppressor-like genes including N-myc downregulated gene-1 (NDRG-1), a tumor suppressor in pancreatic cancer that is also corepressed by EZH2 (a PRC2 complex member). We also observed that Specificity proteins Sp1, Sp3 and Sp4 are overexpressed in Panc1 cells and Sp knockdown or treatment with small molecules that decrease Sp proteins expression also decrease MALAT-1 expression. We also generated Kras-overexpressing p53L/L;LSL-Kras^G12DL/+;p48Cre+/- (p53^L/L/Kras^G12D) and p53L/+;LSLKras^G12DL/+;p48Cre+/- (p53^L/+/Kras^G12D) mice which are p53 homo- and heterozygous, respectively. These mice rapidly develop pancreatic ductal adenocarcinoma-like tumors and were crossed with MALAT-1^-/- mice. We observed that the loss of one or two MALAT-1 alleles in these Ras overexpressing mice does not significantly affect the time to death; however, the loss of MALAT-1 in the p53^-/+ (heterozygote) mice slightly increases their lifespan.

Differentially expressed mRNAs, lncRNAs, and miRNAs with associated co-expression and ceRNA networks in ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic autoimmune disease characterized by systemic inflammation and pathological osteogenesis. However, the genetic etiology of AS remains largely unknown. This study aimed to explore the potential role of coding and noncoding genes in the genetic mechanism of AS. Using microarray analyses, this study comprehensively compared lncRNA, microRNA, and mRNA profiles in hip joint ligament tissues from patients with AS and controls. A total of 661 lncRNAs, 574 mRNAs, and 22 microRNAs were differentially expressed in patients with AS compared with controls. Twenty-two of these genes were then validated using real-time polymerase chain reaction. Gene ontology and pathway analyses were performed to explore the principal functions of differentially expressed genes. The pathways were involved mainly in immune regulation, intercellular signaling, osteogenic differentiation, protein synthesis, and degradation. Gene signal transduction network, coding-noncoding co-expression network, and competing endogenous RNA expression network were constructed using bioinformatics methods. Then, two miRNAs, miR-17-5p and miR-27b-3p, that could increase the osteogenic differentiation potentials of ligament fibroblasts were identified. Finally, differentially expressed, five lncRNAs, four miRNAs, and five mRNAs were validated using quantitative real-time polymerase chain reaction. These results suggested that mRNAs, lncRNAs, and microRNAs were involved in AS pathogenesis. The findings might help characterize the pathogenesis of AS and provide novel therapeutic targets for patients with AS in the future.

Interplay of the iron-regulated metastasis suppressor NDRG1 with epidermal growth factor receptor (EGFR) and oncogenic signaling

The iron-regulated metastasis suppressor N-myc downstream-regulated gene 1 (NDRG1) has been shown to inhibit numerous oncogenic signaling pathways in cancer cells. Recent findings have demonstrated that NDRG1 inhibits the ErbB family of receptors, which function as key inducers of carcinogenesis. NDRG1 attenuates ErbB signaling by inhibiting formation of epidermal growth factor receptor (EGFR)/human epidermal growth factor receptor 2 (HER2) and HER2/HER3 heterodimers and by down-regulating EGFR via a mechanism involving its degradation. Understanding the complex interplay between NDRG1, iron, and ErbB signaling is vital for identifying novel, more effective targets for cancer therapy.

The decreased growth performance and impaired immune function and structural integrity by dietary iron deficiency or excess are associated with TOR, NF-κB, p38MAPK, Nrf2 and MLCK signaling in head kidney, spleen and skin of grass carp (Ctenopharyngodon idella)

This study was conducted to investigate the effects of dietary iron on the growth, and immune function and structural integrity in head kidney, spleen and skin as well as the underlying signaling of young grass carp (Ctenopharyngodon idella). Total 630 grass carp (242.32 ± 0.58 g) were fed diets containing graded levels of iron at 12.15 (basal diet), 35.38, 63.47, 86.43, 111.09, 136.37 mg/kg (diets 2-6 were added with ferrous fumarate) and 73.50 mg/kg (diet 7 was added with ferrous sulfate) diet for 60 days. Then, a challenge test was conducted by infection of Aeromonas hydrophila for 14 days. The results firstly showed that compared with optimal iron level, iron deficiency decreased lysozyme (LZ) and acid phosphatase (ACP) activities, complement 3 (C3), C4 and immunoglobulin M (IgM) contents and down-regulated the mRNA levels of antibacterial peptides, anti-inflammatory cytokines, inhibitor of κBα (IκBα), target of rapamycin (TOR) and ribosomal protein S6 kinase 1 (S6K1), whereas up-regulated the mRNA levels of pro-inflammatory cytokines, nuclear factor kappa B (NF-κB) p65, IκB kinases β (IKKβ) and eIF4E-binding protein (4E-BP) in head kidney and spleen of young grass carp (P < 0.05), indicating that iron deficiency impaired immune function in head kidney and spleen of fish. Secondly, iron deficiency down-regulated the mRNA levels of B-cell lymphoma-2 (Bcl-2), myeloid cell leukemia 1 (Mcl-1), and inhibitor of apoptosis protein (IAP), and decreased activities and mRNA levels of antioxidant enzymes, down-regulated the mRNA levels of NF-E2-related factor 2 (Nrf2) and tight junction complexes, and up-regulated mRNA levels of cysteinyl aspartic acid-protease (caspase) -2, -3, -7, -8, -9, apoptotic protease activating factor-1 (Apaf-1), Bcl-2 associated X protein (Bax), Fas ligand (FasL), p38 mitogen-activated protein kinase (p38MAPK), Kelch-like ECH-associating protein (Keap) 1a, Keap1b, claudin-12 and myosin light chain kinase (MLCK), and increased malondialdehyde (MDA), protein carbonyl (PC) and reactive oxygen species (ROS) contents in head kidney and spleen of young grass carp (P < 0.05), indicating that iron deficiency impaired structural integrity in head kidney and spleen of fish. Thirdly, iron deficiency increased skin hemorrhage and lesion morbidity, and impaired immune function and structural integrity in skin of fish. Fourthly, iron excess decreased growth and impaired the immune function and structural integrity in head kidney, spleen and skin of fish. Besides, in young grass carp, based on PWG and ability against skin hemorrhage and lesion, the efficacy of ferrous fumarate relative to ferrous sulfate was 140.32% and 126.48%, respectively, and the iron requirements based on PWG, ability against skin hemorrhage and lesion, ACP activities and MDA contents in head kidney and spleen were estimated to be 75.65, 87.03, 79.74, 78.93, 83.17 and 82.14 mg/kg diet (based on ferrous fumarate), respectively.

Methionine hydroxy analogue improves intestinal immunological and physical barrier function in young grass carp (Ctenopharyngodon idella)

This study was conducted to test the hypothesis that methionine hydroxy analogue (MHA) enhances the defense against enteritis occurrence via improving intestinal barrier function in fish. After 630 young grass carp (Ctenopharyngodon idella) (259.70 ± 0.47 g) fed six graded levels of MHA (0, 2.4, 4.4, 6.4, 8.5 and 10.5 g/kg diet) and one dl-methionine group (6.4 g/kg diet) for 8 weeks. At the end of feeding trial, 15 fish from each treatment were challenged with Aeromonas hydrophila for 14 days. The results indicated that optimal MHA enhanced the capacity of fish against enteritis emergence, which might be related to the positive effects of MHA on intestinal immunological and physical barrier function in fish. Dietary MHA supplementation enhanced intestinal immunological barrier function via (1) lysozyme (LZM) and acid phosphatase (ACP) activities, complement 3 (C3), C4 and immunoglobulin M (IgM) contents and up-regulated mRNA levels of liver-expressed antimicrobial peptide 2, hepcidin (head kidney), β-defensin-1; (2) repressing p38MAPK/IKKβ/IκBα/NF-κB signaling pathway to down-regulate pro-inflammatory cytokines mRNA levels except IL-8 mRNA level only in mid and distal intestine; (3) potentiating TOR-signal cascades to up-regulate anti-inflammatory cytokines. Meanwhile, dietary MHA supplementation improved intestinal physical barrier via (1) down-regulating c-Jun N-terminal kinase mRNA levels to inhibit death receptor and mitochondria pathways induced apoptosis; (2) modulating Keap1a/Nrf2 system to elevate antioxidant enzymes genes isoforms mRNA levels and corresponding enzymes activities, subsequently alleviate oxidative damage; (3) down-regulating MCLK gene expression to up-regulating occludin, zonula occluden 1 and claudins mRNA levels except claudin-7a and claudin-7b only in the proximal intestine. In conclusion, bases on the capacity defense against enteritis, proximal intestinal malondialdehyde content and lysozyme activity, the optimal MHA supplementation levels were 5.83, 5.59 and 6.07 g/kg diet (4.01 g/kg methionine basal), respectively. This study indicates that MHA exerts a positive effect on fish intestinal health status and a superior efficacy to dl-methionine based on the positive effects.

Suppression of pancreatic cancer growth and metastasis by HMP19 identified through genome-wide shRNA screen

Therapeutic effectiveness against metastatic or even locally advanced pancreatic ductal adenocarcinoma (PDAC) is dismal, with 5‐year survival less than 5%. Even in patients who undergo potentially curative resection, most patients' tumors recur in the liver. Improving therapies targeting or preventing liver metastases is crucial for improving prognosis. To identify genes suppressing metastasis, a genome‐wide shRNA screen was done using the human non‐metastatic PDAC cell line, S2‐028. After identification of candidates, functional validation was done using intrasplenic and orthotopic injections in athymic mice. HMP19 strongly inhibited metastasis but also partially attenuated tumor growth in the pancreas. Knockdown of HMP19 increased localization of activated ERK1/2 in the nucleus, corresponding to facilitated cell proliferation, decreased p27^Kip1 and increased cyclin E1. Over‐expression of HMP19 exerted the opposite effects. Using a tissue microarray of 84 human PDAC, patients with low expression of HMP19 showed significantly higher incidence of liver metastasis (p = 0.0175) and worse prognosis (p = 0.018) after surgery. HMP19, a new metastasis/tumor suppressor in PDAC, appears to alter signaling that leads to cell proliferation and appears to offer prognostic value in human PDAC.

What's new?

Pancreatic cancer is a frequently intractable disease, due in part to its late diagnosis and propensity to metastasize. Indeed, potentially curative resection fails in more than half of patients with pancreatic ductal adenocarcinoma (PDAC), owing to recurrence in the pancreas as well as to metastasis, particularly to the liver. Prognosis may be improved, however, by leveraging the inhibitory strength of novel metastasis suppressors. A promising candidate is HMP19, described in this study. In xenograft models, HMP19 overexpression significantly suppressed PDAC tumor growth and spread. Its elevated expression in clinical samples was associated with reduced liver metastasis and improved patient survival.

A new facet of NDRG1 in pancreatic ductal adenocarcinoma: Suppression of glycolytic metabolism

N-myc downstream-regulated gene 1 (NDRG1) is known as tumor/metastasis suppressor in a variety of cancers including pancreas, being involved in angiogenesis, cancer growth and metastasis. However, the precise molecular mechanism how NDRG1 exerts its inhibitory function in pancreatic cancer remains unclear. In this investigation, we demonstrated that K-Ras plays a vital role in modulating NDRG1 protein level in PDAC cancer cells in vitro, which is mediated through ERK signaling. Noteworthy, K-Ras downstream Akt/mTOR signaling is inhibited upon NDRG1 overexpression, resulting in decease of HIF1α level. Moreover, NDRG1 has a unique role in modulating cancer metabolism of pancreatic ductal adenocarcinoma (PDAC). The mechanism accounting for NDRG1 in modulating aerobic glycolysis, at least partly, relied on its regulation of glycolysis genes including GLUT1, HK2, LDHA and PDK1. Additionally, NDRG1 is shown to suppress the activity of HIF1α, which is responsible for regulation of glycolysis enzymes. The current study is the first to elucidate a unique facet of the potent tumor/metastasis suppressor NDRG1 in the regulation of PDAC glycolysis, leading to important insights into the mechanism by which NDRG1 exert inhibitory function in PDAC.

The metastatic suppressor NDRG1 inhibits EMT, migration and invasion through interaction and promotion of caveolin-1 ubiquitylation in human colorectal cancer cells

N-myc downstream-regulated gene 1 (NDRG1) has been reported to act as a key regulatory molecule in tumor progression-related signaling pathways, especially in tumor metastasis. However, the related mechanism has not been fully discovered yet. Herein we demonstrated that the novel molecule of cell migration and invasion, caveolin-1, has direct interaction with NDRG1 in human colorectal cancer (CRC) cells. Moreover, we discovered that NDRG1 reduces caveolin-1 protein expression through promoting its ubiquitylation and subsequent degradation via the proteasome in CRC cells. In addition, caveolin-1 mediates the suppressive function of NDRG1 in epithelial–mesenchymal transition, migration and invasion in vitro and metastasis in vivo. These results help to fulfill the potential mechanisms of NDRG1 in anti-metastatic treatment for human colorectal cancer.

Novel Thiosemicarbazones Inhibit Lysine-Rich Carcinoembryonic Antigen-Related Cell Adhesion Molecule 1 (CEACAM1) Coisolated (LYRIC) and the LYRIC-Induced Epithelial-Mesenchymal Transition via Upregulation of N-Myc Downstream-Regulated Gene 1 (NDRG1)

Tumor necrosis factor α (TNFα) plays a vital role in cancer progression as it is associated with inflammation and promotion of cancer angiogenesis and metastasis. The effects of TNFα are mediated by its downstream target, the oncogene lysine-rich CEACAM1 coisolated protein (LYRIC, also known as metadherin or astrocyte elevated gene-1). LYRIC plays an important role in activating the nuclear factor-ĸB (NF-κB) signaling pathway, which controls multiple cellular processes, including proliferation, apoptosis, migration, etc. In contrast, the metastasis suppressor N-myc downstream regulated gene 1 (NDRG1) has the opposite effect on the NF-κB pathway, being able to inhibit NF-κB activation and reduce angiogenesis, proliferation, migration, and cancer cell invasion. These potent anticancer properties make NDRG1 an ideal therapeutic target. Indeed, a novel class of thiosemicarbazone anticancer agents that target this molecule has been developed; the lead agent, di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone, has recently entered clinical trials for advanced and resistant cancers. To further elucidate the interaction between NDRG1 and oncogenic signaling, this study for the first time assessed the effects of NDRG1 on the tumorigenic properties of TNFα and its downstream target, LYRIC. We have demonstrated that NDRG1 inhibits the TNFα-mediated epithelial-to-mesenchymal transition. Further, NDRG1 also potently inhibited LYRIC expression, with a negative feedback loop existing between these two molecules. Examining the mechanism involved, we demonstrated that NDRG1 inhibited phosphatidylinositol 3-kinase/AKT signaling, leading to reduced levels of the LYRIC transcriptional activator, c-Myc. Finally, we demonstrated that novel thiosemicarbazones that upregulate NDRG1 also inhibit LYRIC expression, further highlighting their marked potential for cancer treatment.

The molecular effect of metastasis suppressors on Src signaling and tumorigenesis: new therapeutic targets

A major problem for cancer patients is the metastasis of cancer cells from the primary tumor. This involves: (1) migration through the basement membrane; (2) dissemination via the circulatory system; and (3) invasion into a secondary site. Metastasis suppressors, by definition, inhibit metastasis at any step of the metastatic cascade. Notably, Src is a non-receptor, cytoplasmic, tyrosine kinase, which becomes aberrantly activated in many cancer-types following stimulation of plasma membrane receptors (e.g., receptor tyrosine kinases and integrins). There is evidence of a prominent role of Src in tumor progression-related events such as the epithelial–mesenchymal transition (EMT) and the development of metastasis. However, the precise molecular interactions of Src with metastasis suppressors remain unclear. Herein, we review known metastasis suppressors and summarize recent advances in understanding the mechanisms of how these proteins inhibit metastasis through modulation of Src. Particular emphasis is bestowed on the potent metastasis suppressor, N-myc downstream regulated gene 1 (NDRG1) and its interactions with the Src signaling cascade. Recent studies demonstrated a novel mechanism through which NDRG1 plays a significant role in regulating cancer cell migration by inhibiting Src activity. Moreover, we discuss the rationale for targeting metastasis suppressor genes as a sound therapeutic modality, and we review several examples from the literature where such strategies show promise. Collectively, this review summarizes the essential interactions of metastasis suppressors with Src and their effects on progression of cancer metastasis. Moreover, interesting unresolved issues regarding these proteins as well as their potential as therapeutic targets are also discussed.

Methionine hydroxy analogue enhanced fish immunity via modulation of NF-κB, TOR, MLCK, MAPKs and Nrf2 signaling in young grass carp (Ctenopharyngodon idella)

Our study investigated the effect of dietary methionine hydroxy analogue (MHA) on growth and immunity (head kidney, spleen and skin) of young grass carp (Ctenopharyngodon idella). A total of 630 grass carp (259.70 ± 0.47 g) were fed graded levels of MHA (0, 2.4, 4.4, 6.4, 8.5 and 10.5 g/kg diet) and one dl-methionine (DLM) group (6.4 g/kg diet) for 8 weeks. At the end of the feeding trial, fish were challenged with Aeromonas hydrophila for 14 days. The results indicated that optimal MHA increased lysozyme (LZ) and acid phosphatase (ACP) activities, complement 3 (C3), C4 and immunoglobulin M (IgM) contents and up-regulated mRNA levels of liver expressed antimicrobial peptide 2, hepcidin (head kidney), β-defensin-1 in the immune organs (P < 0.05), suggesting that MHA could enhance antimicrobial ability of fish. Meanwhile, optimal MHA enhanced the immune function of immune organs via down-regulating pro-inflammatory cytokines mRNA levels and up-regulated anti-inflammatory cytokines mRNA levels, which might be attributed to the down-regulation of nuclear factor κB p65, c-Rel, IκB kinase β, p38 mitogen activated protein kinase, eIF4E-binding protein1 (4E-BP1) and 4E-BP2 mRNA levels and up-regulation of inhibitor of κBα, ribosomal protein S6 kinase 1 and target of rapamycin mRNA levels (P < 0.05). In addition, optimal MHA improved cellular structure integrity of immune organs via repressing death receptor and mitochondria pathways induced apoptosis, which might be related to the down-regulation of c-Jun-N-terminal kinase mRNA levels (P < 0.05). Simultaneously, optimal MHA improved cellular structure integrity of immune organs via elevating glutathione contents, antioxidant enzymes activities and corresponding isoforms mRNA levels to attenuate oxidative damage, which might be to the up-regulation of NF-E2-related factor 2 mRNA levels and down-regulation of Kelch-like ECH-associating protein 1a mRNA levels (P < 0.05). Besides, optimal MHA improved intercellular structure integrity of immune organs via up-regulating the mRNA levels of intercellular tight junctions-related genes, which might be owing to the down-regulation of myosin light chain kinase mRNA levels (P < 0.05). In conclusion, MHA exerted a positive effect on the immune function and structural integrity of immune organs in fish. Furthermore, according to the positive effect, MHA was superior to DLM in grass carp. However, based on the growth performance, the efficacy of MHA relative to DLM was 97%. Finally, on the premise of the basal diet containing 4.01 g/kg methionine, the optimal MHA supplementation levels based on feed intake, PWG, defense against skin hemorrhage and lesion, LZ and ACP activities, IgM content, against malondialdehyde, protein carbonyl and ROS in the head kidney of young grass carp were 5.07, 5.21, 5.76, 5.90, 5.88, 5.80, 6.22, 5.68 and 6.85 g/kg diet, respectively.