N-acetylcysteine decreases malignant characteristics of glioblastoma cells by inhibiting Notch2 signaling

A new opportunity for N-acetylcysteine. An outline of its classic antioxidant effects and its pharmacological potential as an epigenetic modulator in liver diseases treatment

Liver diseases represent a worldwide health problem accountable for two million deaths per year. Oxidative stress is critical for the development of these diseases. N-acetyl cysteine (NAC) is effective in preventing liver damage, both in experimental and clinical studies, and evidence has shown that the pharmacodynamic mechanisms of NAC are related to its antioxidant nature and ability to modulate key signaling pathways. Here, we provide a comprehensive description of the beneficial effects of NAC in the treatment of liver diseases, addressing the first evidence of its role as a scavenger and precursor of reduced glutathione, along with studies showing its immunomodulatory action, as well as the ability of NAC to modulate epigenetic hallmarks. We searched the PubMed database using the following keywords: oxidative stress, liver disease, epigenetics, antioxidants, NAC, and antioxidant therapies. There was no time limit to gather all available information on the subject. NAC has shown efficacy in treating liver damage, exerting mechanisms of action different from those of free radical scavengers. Like different antioxidant therapies, its effectiveness and safety are related to the administered dose; therefore, designing new pharmacological formulations for this drug is imperative to achieve an adequate response. Finally, there is still much to explore regarding its effect on epigenetic marker characteristics of liver damage, turning it into a drug with broad therapeutic potential. According to the literature reviewed, NAC could be an appropriate option in clinical studies related to hepatic injury and, in the future, a repurposing alternative for treating liver diseases.

Targeting the Notch-Furin axis with 2-hydroxyoleic acid: a key mechanism in glioblastoma therapy

PURPOSE

Glioblastomas (GBMs) are highly treatment-resistant and aggressive brain tumors. 2OHOA, which is currently running a phase IIB/III clinical trial for newly diagnosed GBM patients, was developed in the context of melitherapy. This therapy focuses on the regulation of the membrane's structure and organization with the consequent modulation of certain cell signals to revert the pathological state in several disorders. Notch signaling has been associated with tumorigenesis and cell survival, potentially driving the pathogenesis of GBM. The current study aims to determine whether 2OHOA modulates the Notch pathway as part of its antitumoral mechanism.

METHODS

2OHOA's effect was evaluated on different components of the pathway by Western blot, Q-PCR, and confocal microscopy. Notch receptor processing was analyzed by subcellular fractionation and colocalization studies. Furin activity was evaluated under cleavage of its substrate by fluorescence assays and its binding affinity to 2OHOA was determined by surface plasmon resonance.

RESULTS

We found that 2OHOA inhibits Notch2 and Notch3 signaling by dual mechanism. Notch2 inhibition is unleashed by impairment of its processing through the inactivation of furin activity by physical association. Instead, Notch3 is transcriptionally downregulated leading to a lower activation of the pathway. Moreover, we also found that HES1 overexpression highlighted the relevance of this pathway in the 2OHOA pharmacological efficacy.

CONCLUSION

These findings report that the inhibition of Notch signaling by 2OHOA plays a role in its anti-tumoral activity, an effect that may be driven through direct inhibition of furin, characterizing a novel target of this bioactive lipid to treat GBM.

A disulfiram derivative against lung cancer via the Notch signaling pathway without neurotoxicity and hepatotoxicity

The exploration of novel anti-lung cancer small-molecule drugs is important for drug resistance and adverse effects of chemotherapeutic drugs in current clinics. Disulfiram (DSF), as an antidote, has been proven to have excellent antitumor effects in combination with copper (Cu). However, the risk for potential neurotoxicity and hepatotoxicity in clinical use, as well as its poor water solubility, limits its use. In this study, we identified a DSF derivative, S-(N,N-diethyldithiocarbamoyl)-N-acetyl-L-cysteine, which could greatly increase the water solubility by converting it to a calcium salt (DS-NAC). The anti-lung cancer pharmacodynamic studies in vitro of DS-NAC were evaluated and a mouse model of lung cancer in situ was established to explore the therapeutic effects of DS-NAC compared with DSF and oxaliplatin (OXA). The results demonstrated that DS-NAC combined with Cu had superior cytotoxicity to DSF and OXA in the CCK8 assay against lung cancer cells, and exhibited potent anti-metastatic, epithelial-mesenchymal transition inhibition. In addition, DS-NAC showed better antitumor effects than DSF and comparable effects to OXA in lung cancer in situ model. In terms of the antitumor mechanism, we discovered that DS-NAC in combination with Cu exerted a greater inhibitory effect on the Notch pathway than DSF, which may account for its excellent antitumor effects. Finally, we verified the safety of DS-NAC in vivo, showing lower hepatotoxicity and neurotoxicity compared with DSF and OXA. DS-NAC is a promising anti-lung cancer drug with a favorable safety profile.

Niosomes loading N-acetyl-L-cysteine for cancer treatment in vivo study

Scientists are seeking to find an effective treatment for tumors that has no side effects. N-Acetyl-l-cysteine (NAC) is a thiol compound extracted from garlic. Current study explores the potential of NAC-loaded niosomes (NAC-NIO) for tumor treatment in mice. NAC-loaded niosomes' efficiency, morphology, UV absorption, size distribution, zeta potential, release, and FTIR analysis were evaluated. For vivo study, 25 male BALB/c mice were divided to five groups: gp1 negative control (receive saline), gp2 positive control (tumor group), gp3 treated with NAC, gp4 treated with NAC-NIO at the same time of tumor injection, and gp5 treated with NAC-NIO after tumor growth (day 14). The impact of NAC-NIO on the tumor treatment was evaluated by measuring tumor size progress, comet assay, oxidative stress parameters (GSH, nitric oxide, MDA), western blot analysis, and histopathological investigation of tissues. NAC-NIO showed 72 ± 3% encapsulation efficiency and zeta potential - 5.95 mV with spherical shape. It was found that oral administration of NAC-NIO in a dose of 50 mg/kg provided significant protection against tumor cells. Our formulation decreases DNA injury significantly (P < 0.05). It was noticed that NAC-NIO can increase oxidative stress levels in tumor tissue. On the other hand, the caspase 3 and caspase 9 gene expression were upregulated significantly (P < 0.001) in mice administrated NAC-NIO compared with all other groups. Histological studies confirmed the protective effect of NAC-NIO against tumor especially for treatment during tumor growth protocol. The results suggested that oral delivery of NAC-NIO formulation improved antioxidant effect.

Mechanism of Notch Signaling Pathway in Malignant Progression of Glioblastoma and Targeted Therapy

Glioblastoma multiforme (GBM) is the most aggressive form of glioma and the most common primary tumor of the central nervous system. Despite significant advances in clinical management strategies and diagnostic techniques for GBM in recent years, it remains a fatal disease. The current standard of care includes surgery, radiation, and chemotherapy, but the five-year survival rate for patients is less than 5%. The search for a more precise diagnosis and earlier intervention remains a critical and urgent challenge in clinical practice. The Notch signaling pathway is a critical signaling system that has been extensively studied in the malignant progression of glioblastoma. This highly conserved signaling cascade is central to a variety of biological processes, including growth, proliferation, self-renewal, migration, apoptosis, and metabolism. In GBM, accumulating data suggest that the Notch signaling pathway is hyperactive and contributes to GBM initiation, progression, and treatment resistance. This review summarizes the biological functions and molecular mechanisms of the Notch signaling pathway in GBM, as well as some clinical advances targeting the Notch signaling pathway in cancer and glioblastoma, highlighting its potential as a focus for novel therapeutic strategies.

Enhanced Inhibition of Cancer Cell Migration by a Planar Catechin Analog

Cancer cell migration is related to malignancy and patient prognosis. We previously reported that intracellular reactive oxygen species (ROS) promoted cancer cellular migration and invasion and that an antioxidant enzyme could help to attenuate the malignancy. Catechin is known as an antioxidant, and we have developed a catechin analog, planar catechin, which showed an antioxidant activity significantly stronger than that of the parent (+)-catechin. In this study, we examined the effects of the planar catechin on the migration of gastric normal and cancer cells. A scratched assay showed that the planar catechin suppressed the cellular migration rates in both normal and cancer cells, while the prevention levels in cancer cells were remarkable compared to the normal cells. These results suggest that the planar catechin with the enhanced antioxidant activity effectively scavenged the ROS overexpressed in the cancer cells and inhibited cancer cellular activities, including migration.

Tumor cell-intrinsic PD-1 promotes Merkel cell carcinoma growth by activating downstream mTOR-mitochondrial ROS signaling

Merkel cell carcinoma (MCC) is a rare and aggressive skin cancer. Inhibitors targeting the programmed cell death 1 (PD-1) immune checkpoint have improved MCC patient outcomes by boosting antitumor T cell immunity. Here, we identify PD-1 as a growth-promoting receptor intrinsic to MCC cells. In human MCC lines and clinical tumors, RT-PCR-based sequencing, immunoblotting, flow cytometry, and immunofluorescence analyses demonstrated PD-1 gene and protein expression by MCC cells. MCC-PD-1 ligation enhanced, and its inhibition or silencing suppressed, in vitro proliferation and in vivo tumor xenograft growth. Consistently, MCC-PD-1 binding to PD-L1 or PD-L2 induced, while antibody-mediated PD-1 blockade inhibited, protumorigenic mTOR signaling, mitochondrial (mt) respiration, and ROS generation. Last, pharmacologic inhibition of mTOR or mtROS reversed MCC-PD-1:PD-L1-dependent proliferation and synergized with PD-1 checkpoint blockade in suppressing tumorigenesis. Our results identify an MCC-PD-1-mTOR-mtROS axis as a tumor growth-accelerating mechanism, the blockade of which might contribute to clinical response in patients with MCC.

Exploring the Multiple Roles of Notch1 in Biological Development: An Analysis and Study Based on Phylogenetics and Transcriptomics

At present, there is a research gap concerning the specific functions and mechanisms of the Notch gene family and its signaling pathway in jawless vertebrates. In this study, we identified a Notch1 homologue (Lr. Notch1) in the Lethenteron reissneri database. Through bioinformatics analysis, we identified Lr. Notch1 as the likely common ancestor gene of the Notch gene family in higher vertebrates, indicating a high degree of conservation in the Notch gene family and its signaling pathways. To validate the biological function of Lr. Notch1, we conducted targeted silencing of Lr. Notch1 in L. reissneri and analyzed the resultant gene expression profile before and after silencing using transcriptome analysis. Our findings revealed that the silencing of Lr. Notch1 resulted in differential expression of pathways and genes associated with signal transduction, immune regulation, and metabolic regulation, mirroring the biological function of the Notch signaling pathway in higher vertebrates. This article systematically elucidated the origin and evolution of the Notch gene family while also validating the biological function of Lr. Notch1. These insights offer valuable clues for understanding the evolution of the Notch signaling pathway and establish a foundation for future research on the origin of the Notch signaling pathway, as well as its implications in human diseases and immunomodulation.

DNMT1 determines osteosarcoma cell resistance to apoptosis by associatively modulating DNA and mRNA cytosine-5 methylation

Cellular apoptosis is a central mechanism leveraged by chemotherapy to treat human cancers. 5-Methylcytosine (m5C) modifications installed on both DNA and mRNA are documented to regulate apoptosis independently. However, the interplay or crosstalk between them in cellular apoptosis has not yet been explored. Here, we reported that promoter methylation by DNMT1 coordinated with mRNA methylation by NSun2 to regulate osteosarcoma cell apoptosis. DNMT1 was induced during osteosarcoma cell apoptosis triggered by chemotherapeutic drugs, whereas NSun2 expression was suppressed. DNMT1 was found to repress NSun2 expression by methylating the NSun2 promoter. Moreover, DNMT1 and NSun2 regulate the anti-apoptotic genes AXL, NOTCH2, and YAP1 through DNA and mRNA methylation, respectively. Upon exposure to cisplatin or doxorubicin, DNMT1 elevation drastically reduced the expression of these anti-apoptotic genes via enhanced promoter methylation coupled with NSun2 ablation-mediated attenuation of mRNA methylation, thus rendering osteosarcoma cells to apoptosis. Collectively, our findings establish crosstalk of importance between DNA and RNA cytosine methylations in determining osteosarcoma resistance to apoptosis during chemotherapy, shedding new light on future treatment of osteosarcoma, and adding additional layers to the control of gene expression at different epigenetic levels.

Pan-cancer tRNA-derived fragment CAT1 coordinates RBPMS to stabilize NOTCH2 mRNA to promote tumorigenesis

Transfer RNA-derived fragments (tRFs) are a class of small non-coding regulatory RNAs that are involved in the pathophysiology of many diseases. However, the role of tRFs in cancer progression remains largely elusive. Here, we demonstrate that a pan-cancer 3'-tRF, CAT1 (cancer associated tRF 1), is ubiquitously upregulated in tumors and associated with poor prognosis of a variety of cancers, including lung cancer. The upregulated CAT1 in cancer cells binds to RNA-binding protein with multiple splicing (RBPMS) and displaces NOTCH2 association from RBPMS, thereby inhibiting the subsequent CCR4-NOT deadenylation-complex-mediated NOTCH2 mRNA decay. The CAT1-enhanced NOTCH2 expression promotes lung cancer cell proliferation and metastasis in vitro and in vivo. In addition, plasma CAT1 levels are substantially increased in patients with lung cancer compared to non-cancer control subjects. Our findings reveal an intrinsic connection between cancer-specific upregulation of CAT1 and cancer progression, show the regulation of NOTCH signaling in cancer by a 3'-tRF, and highlight its great clinical potential.

The initiation of oxidative stress and therapeutic strategies in wound healing

When the production of reactive oxygen species (ROS) is overloaded surpassing the capacity of the reductive rheostat, mammalian cells undergo a series of oxidative damage termed oxidative stress (OS). This phenomenon is ubiquitously detected in many human pathological conditions. Wound healing program implicates continuous neovascularization, cell proliferation, and wound remodeling. Increasing evidence indicates that reactive oxygen species (ROS) have profound impacts on the wound healing process through regulating a series of the physiological and pathological program including inflammatory response, cell proliferation, angiogenesis, granulation as well as extracellular matrix formation. In most pathological wound healing processes, excessive ROS exerts a negative role on the wound healing process. Interestingly, the moderate increase of ROS levels is beneficial in killing bacteria at the wound site, which creates a sterile niche for revascularization. In this review, we discussed the physiological rhythms of wound healing and the role of ROS in this progress, aim to explore the potential manipulation of OS as a promising therapeutic avenue.

NAC, NAC, Knockin' on Heaven's door: Interpreting the mechanism of action of N-acetylcysteine in tumor and immune cells

N-acetylcysteine (NAC) has been used as a direct scavenger of reactive oxygen species (hydrogen peroxide, in particular) and an antioxidant in cancer biology and immuno-oncology. NAC is the antioxidant drug most frequently employed in studies using tumor cells, immune cells, and preclinical mouse xenografts. Most studies use redox-active fluorescent probes such as dichlorodihydrofluorescein, hydroethidine, mitochondria-targeted hydroethidine, and proprietary kit-based probes (i.e., CellROX Green and CellROX Red) for intracellular detection of superoxide or hydrogen peroxide. Inhibition of fluorescence by NAC was used as a key experimental observation to support the formation of reactive oxygen species and redox mechanisms proposed for ferroptosis, tumor metastasis, and redox signaling in the tumor microenvironment. Reactive oxygen species such as superoxide and hydrogen peroxide stimulate or abrogate tumor cells and immune cells depending on multiple factors. Understanding the mechanism of antioxidants is crucial for interpretation of the results. Because neither NAC nor the fluorescent probes indicated above react directly with hydrogen peroxide, it is critically important to reinterpret the results to advance our understanding of the mechanism of action of NAC and shed additional mechanistic insight on redox-regulated signaling in tumor biology. To this end, this review is focused on how NAC could affect multiple pathways in cancer cells, including iron signaling, ferroptosis, and the glutathione-dependent antioxidant and redox signaling mechanism, and how NAC could inhibit oxidation of the fluorescent probes through multiple mechanisms.

Antioxidants in brain tumors: current therapeutic significance and future prospects

Brain cancer is regarded among the deadliest forms of cancer worldwide. The distinct tumor microenvironment and inherent characteristics of brain tumor cells virtually render them resistant to the majority of conventional and advanced therapies. Oxidative stress (OS) is a key disruptor of normal brain homeostasis and is involved in carcinogenesis of different forms of brain cancers. Thus, antioxidants may inhibit tumorigenesis by preventing OS induced by various oncogenic factors. Antioxidants are hypothesized to inhibit cancer initiation by endorsing DNA repair and suppressing cancer progression by creating an energy crisis for preneoplastic cells, resulting in antiproliferative effects. These effects are referred to as chemopreventive effects mediated by an antioxidant mechanism. In addition, antioxidants minimize chemotherapy-induced nonspecific organ toxicity and prolong survival. Antioxidants also support the prooxidant chemistry that demonstrate chemotherapeutic potential, particularly at high or pharmacological doses and trigger OS by promoting free radical production, which is essential for activating cell death pathways. A growing body of evidence also revealed the roles of exogenous antioxidants as adjuvants and their ability to reverse chemoresistance. In this review, we explain the influences of different exogenous and endogenous antioxidants on brain cancers with reference to their chemopreventive and chemotherapeutic roles. The role of antioxidants on metabolic reprogramming and their influence on downstream signaling events induced by tumor suppressor gene mutations are critically discussed. Finally, the review hypothesized that both pro- and antioxidant roles are involved in the anticancer mechanisms of the antioxidant molecules by killing neoplastic cells and inhibiting tumor recurrence followed by conventional cancer treatments. The requirements of pro- and antioxidant effects of exogenous antioxidants in brain tumor treatment under different conditions are critically discussed along with the reasons behind the conflicting outcomes in different reports. Finally, we also mention the influencing factors that regulate the pharmacology of the exogenous antioxidants in brain cancer treatment. In conclusion, to achieve consistent clinical outcomes with antioxidant treatments in brain cancers, rigorous mechanistic studies are required with respect to the types, forms, and stages of brain tumors. The concomitant treatment regimens also need adequate consideration.

Rewired Metabolism of Amino Acids and Its Roles in Glioma Pathology

Amino acids (AAs) are indispensable building blocks of diverse bio-macromolecules as well as functional regulators for various metabolic processes. The fact that cancer cells live with a voracious appetite for specific AAs has been widely recognized. Glioma is one of the most lethal malignancies occurring in the central nervous system. The reprogrammed metabolism of AAs benefits glioma proliferation, signal transduction, epigenetic modification, and stress tolerance. Metabolic alteration of specific AAs also contributes to glioma immune escape and chemoresistance. For clinical consideration, fluctuations in the concentrations of AAs observed in specific body fluids provides opportunities to develop new diagnosis and prognosis markers. This review aimed at providing an extra dimension to understanding glioma pathology with respect to the rewired AA metabolism. A deep insight into the relevant fields will help to pave a new way for new therapeutic target identification and valuable biomarker development.

Cysteamine affects skeletal development and impairs motor behavior in zebrafish

Cysteamine is a kind of feed additive commonly used in agricultural production. It is also the only targeted agent for the treatment of cystinosis, and there are some side effects in clinical applications. However, the potential skeletal toxicity remains to be further elucidated. In this study, a zebrafish model was for the first time utilized to synthetically appraise the skeletal developmental defects induced by cysteamine. The embryos were treated with 0.35, 0.70, and 1.05 mM cysteamine from 6 h post fertilization (hpf) to 72 hpf. Substantial skeletal alterations were manifested as shortened body length, chondropenia, and abnormal somite development. The results of spontaneous tail coiling at 24 hpf and locomotion at 120 hpf revealed that cysteamine decreased behavioral abilities. Moreover, the level of oxidative stress in the skeleton ascended after cysteamine exposure. Transcriptional examination showed that cysteamine upregulated the expression of osteoclast-related genes but did not affect osteoblast-related genes expression. Additionally, cysteamine exposure caused the downregulation of the Notch signaling and activating of Notch signaling partially attenuated skeletal defects. Collectively, our study suggests that cysteamine leads to skeletal developmental defects and reduces locomotion activity. This hazard may be associated with cysteamine-mediated inhibition of the Notch signaling and disorganization of notochordal cells due to oxidative stress and apoptosis.

Current Opportunities for Targeting Dysregulated Neurodevelopmental Signaling Pathways in Glioblastoma

Glioblastoma (GBM) is the most common and highly lethal type of brain tumor, with poor survival despite advances in understanding its complexity. After current standard therapeutic treatment, including tumor resection, radiotherapy and concomitant chemotherapy with temozolomide, the median overall survival of patients with this type of tumor is less than 15 months. Thus, there is an urgent need for new insights into GBM molecular characteristics and progress in targeted therapy in order to improve clinical outcomes. The literature data revealed that a number of different signaling pathways are dysregulated in GBM. In this review, we intended to summarize and discuss current literature data and therapeutic modalities focused on targeting dysregulated signaling pathways in GBM. A better understanding of opportunities for targeting signaling pathways that influences malignant behavior of GBM cells might open the way for the development of novel GBM-targeted therapies.

Bromodomains in Human-Immunodeficiency Virus-Associated Neurocognitive Disorders: A Model of Ferroptosis-Induced Neurodegeneration

Human immunodeficiency virus (HIV)-associated neurocognitive disorders (HAND) comprise a group of illnesses marked by memory and behavioral dysfunction that can occur in up to 50% of HIV patients despite adequate treatment with combination antiretroviral drugs. Iron dyshomeostasis exacerbates HIV-1 infection and plays a major role in Alzheimer's disease pathogenesis. In addition, persons living with HIV demonstrate a high prevalence of neurodegenerative disorders, indicating that HAND provides a unique opportunity to study ferroptosis in these conditions. Both HIV and combination antiretroviral drugs increase the risk of ferroptosis by augmenting ferritin autophagy at the lysosomal level. As many viruses and their proteins exit host cells through lysosomal exocytosis, ferroptosis-driving molecules, iron, cathepsin B and calcium may be released from these organelles. Neurons and glial cells are highly susceptible to ferroptosis and neurodegeneration that engenders white and gray matter damage. Moreover, iron-activated microglia can engage in the aberrant elimination of viable neurons and synapses, further contributing to ferroptosis-induced neurodegeneration. In this mini review, we take a closer look at the role of iron in the pathogenesis of HAND and neurodegenerative disorders. In addition, we describe an epigenetic compensatory system, comprised of bromodomain-containing protein 4 (BRD4) and microRNA-29, that may counteract ferroptosis by activating cystine/glutamate antiporter, while lowering ferritin autophagy and iron regulatory protein-2. We also discuss potential interventions for lysosomal fitness, including ferroptosis blockers, lysosomal acidification, and cathepsin B inhibitors to achieve desirable therapeutic effects of ferroptosis-induced neurodegeneration.

Oxidative Stress and Redox Signaling in the Pathophysiology of Liver Diseases

The increased production of derivatives of molecular oxygen and nitrogen in the form of reactive oxygen species (ROS) and reactive nitrogen species (RNS) lead to molecular damage called oxidative stress. Under normal physiological conditions, the ROS generation is tightly regulated in different cells and cellular compartments. Any disturbance in the balance between the cellular generation of ROS and antioxidant balance leads to oxidative stress. In this article, we discuss the sources of ROS (endogenous and exogenous) and antioxidant mechanisms. We also focus on the pathophysiological significance of oxidative stress in various cell types of the liver. Oxidative stress is implicated in the development and progression of various liver diseases. We narrate the master regulators of ROS-mediated signaling and their contribution to liver diseases. Nonalcoholic fatty liver diseases (NAFLD) are influenced by a "multiple parallel-hit model" in which oxidative stress plays a central role. We highlight the recent findings on the role of oxidative stress in the spectrum of NAFLD, including fibrosis and liver cancer. Finally, we provide a brief overview of oxidative stress biomarkers and their therapeutic applications in various liver-related disorders. Overall, the article sheds light on the significance of oxidative stress in the pathophysiology of the liver. © 2022 American Physiological Society. Compr Physiol 12:3167-3192, 2022.

E3 Ubiquitin Ligase Regulators of Notch Receptor Endocytosis: From Flies to Humans

Notch is a developmental receptor, conserved in the evolution of the metazoa, which regulates cell fate proliferation and survival in numerous developmental contexts, and also regulates tissue renewal and repair in adult organisms. Notch is activated by proteolytic removal of its extracellular domain and the subsequent release of its intracellular domain, which then acts in the nucleus as part of a transcription factor complex. Numerous regulatory mechanisms exist to tune the amplitude, duration and spatial patterning of this core signalling mechanism. In Drosophila, Deltex (Dx) and Suppressor of dx (Su(dx)) are E3 ubiquitin ligases which interact with the Notch intracellular domain to regulate its endocytic trafficking, with impacts on both ligand-dependent and ligand-independent signal activation. Homologues of Dx and Su(dx) have been shown to also interact with one or more of the four mammalian Notch proteins and other target substrates. Studies have shown similarities, specialisations and diversifications of the roles of these Notch regulators. This review collates together current research on vertebrate Dx and Su(dx)-related proteins, provides an overview of their various roles, and discusses their contributions to cell fate regulation and disease.

Rosmarinic Acid Decreases the Malignancy of Pancreatic Cancer Through Inhibiting Gli1 Signaling

BACKGROUND

Rosmarinic acid (RA) has been shown to exert anti-tumor effects on various types of cancer. However, its roles in the treatment of pancreatic ductal adenocarcinoma (PDAC) and the underlying mechanisms remain elusive.

PURPOSE

The present study aimed to investigate the therapeutic effects of RA on PDAC as well as the underlying mechanisms.

STUDY DESIGN

Evaluation of the effects of RA on PDAC malignancy both in vitro and in vivo.

METHODS

Cell counting kit 8 (CCK8) assay, colony formation assay, 5-Ethynyl-2'-deoxyuridine (EDU) incorporation assay, cell cycle analysis, and apoptosis assay were conducted to assess the inhibitory effect of RA on PDAC cell proliferation. Meanwhile, western blotting and RT-qPCR assay were performed to detect the target gene expression at protein and mRNA levels, respectively. Moreover, the in vivo anti-tumor activities of RA were assayed in an xenograft mouse model of PDAC.

RESULTS

RA dramatically down-regulated Gli1 and its downstream targets. Further studies showed that RA prevents the nuclear translocation of Gli1, while promoting the degradation of cytosolic Gli1 via the proteasome pathway. Moreover, we observed that RA induced G1/S cell cycle arrest and apoptosis in the PDAC cells through regulating the expression of P21, P27, CDK2, Cyclin E, Bax, and Bcl-2, it inhibited the PDAC cell migration and invasion via E-cadherin and MMP-9. Notably, Gli1 overexpression markedly reversed the above RA-induced effects on PDAC cells, whereas Gli1 knockdown enhanced the effects. Additionally, the in vivo assays demonstrated that RA suppresses the tumor growth of PDAC presumably by inhibiting Gli1.

CONCLUSION

We provided evidence that RA restrained the nuclear translocation of Gli1 and facilitates Gli1 degradation via proteasome pathway, reducing the malignancy of PDAC cells. These findings implicated RA as a therapeutic agent for PDAC.

Targeting Notch to Maximize Chemotherapeutic Benefits: Rationale, Advanced Strategies, and Future Perspectives

Simple Summary

The Notch signaling pathway regulates cell proliferation, apoptosis, stem cell self-renewal, and differentiation in a context-dependent fashion both during embryonic development and in adult tissue homeostasis. Consistent with its pleiotropic physiological role, unproper activation of the signaling promotes or counteracts tumor pathogenesis and therapy response in distinct tissues. In the last twenty years, a wide number of studies have highlighted the anti-cancer potential of Notch-modulating agents as single treatment and in combination with the existent therapies. However, most of these strategies have failed in the clinical exploration due to dose-limiting toxicity and low efficacy, encouraging the development of novel agents and the design of more appropriate combinations between Notch signaling inhibitors and chemotherapeutic drugs with improved safety and effectiveness for distinct types of cancer.

Abstract

Notch signaling guides cell fate decisions by affecting proliferation, apoptosis, stem cell self-renewal, and differentiation depending on cell and tissue context. Given its multifaceted function during tissue development, both overactivation and loss of Notch signaling have been linked to tumorigenesis in ways that are either oncogenic or oncosuppressive, but always context-dependent. Notch signaling is critical for several mechanisms of chemoresistance including cancer stem cell maintenance, epithelial-mesenchymal transition, tumor-stroma interaction, and malignant neovascularization that makes its targeting an appealing strategy against tumor growth and recurrence. During the last decades, numerous Notch-interfering agents have been developed, and the abundant preclinical evidence has been transformed in orphan drug approval for few rare diseases. However, the majority of Notch-dependent malignancies remain untargeted, even if the application of Notch inhibitors alone or in combination with common chemotherapeutic drugs is being evaluated in clinical trials. The modest clinical success of current Notch-targeting strategies is mostly due to their limited efficacy and severe on-target toxicity in Notch-controlled healthy tissues. Here, we review the available preclinical and clinical evidence on combinatorial treatment between different Notch signaling inhibitors and existent chemotherapeutic drugs, providing a comprehensive picture of molecular mechanisms explaining the potential or lacking success of these combinations.

Sirt1 deficiency upregulates glutathione metabolism to prevent hepatocellular carcinoma initiation in mice

Sirtuin-1 (SIRT1) is involved in various metabolic pathways, including fatty acid synthesis and gluconeogenesis in the liver. However, its role in initiation and progression of liver cancer remains unclear. Studying Sirt1 liver-specific knockout (LKO) mice in combination with diethylnitrosamine (DEN) treatment, we demonstrated that loss of Sirt1 rendered mice resistant to DEN-induced hepatocellular carcinoma (HCC) development. RNA-seq revealed that livers from LKO mice exhibited an enrichment in glutathione metabolism eight months after DEN challenge. Sirt1 deficiency elevated the expression of glutathione-s-transferase family genes by increasing the level of Nrf2, a key regulator of glutathione metabolism. Hence, LKO livers displayed a reductive environment with an increased ratio of GSH to GSSG and an elevated GSH level. Furthermore, using CRISPR knockout techniques, we confirmed that the impairment of HCC formation in LKO mice is mainly dependent on NRF2 signaling. Meanwhile, HCC induced by DEN could be blocked by the administration of N-acetyl cysteine (NAC) when administered one month after DEN challenge. However, NAC treatment starting five months after DEN injection was not able to prevent tumor development. In conclusion, our findings indicate that a reductive environment orchestrated by glutathione metabolism at an early stage can prevent the initiation of HCC.

N-Acetylcysteine (NAC): Impacts on Human Health

N-acetylcysteine (NAC) is a medicine widely used to treat paracetamol overdose and as a mucolytic compound. It has a well-established safety profile, and its toxicity is uncommon and dependent on the route of administration and high dosages. Its remarkable antioxidant and anti-inflammatory capacity is the biochemical basis used to treat several diseases related to oxidative stress and inflammation. The primary role of NAC as an antioxidant stems from its ability to increase the intracellular concentration of glutathione (GSH), which is the most crucial biothiol responsible for cellular redox imbalance. As an anti-inflammatory compound, NAC can reduce levels of tumor necrosis factor-alpha (TNF-α) and interleukins (IL-6 and IL-1β) by suppressing the activity of nuclear factor kappa B (NF-κB). Despite NAC's relevant therapeutic potential, in several experimental studies, its effectiveness in clinical trials, addressing different pathological conditions, is still limited. Thus, the purpose of this chapter is to provide an overview of the medicinal effects and applications of NAC to human health based on current therapeutic evidence.

N-Acetylcysteine: A Review of Clinical Usefulness (an Old Drug with New Tricks)

OBJECTIVE

To review the clinical usefulness of N-acetylcysteine (NAC) as treatment or adjunctive therapy in a number of medical conditions. Use in Tylenol overdose, cystic fibrosis, and chronic obstructive lung disease has been well documented, but there is emerging evidence many other conditions would benefit from this safe, simple, and inexpensive intervention. Quality of Evidence. PubMed, several books, and conference proceedings were searched for articles on NAC and health conditions listed above reviewing supportive evidence. This study uses a traditional integrated review format, and clinically relevant information is assessed using the American Family Physician Evidence-Based Medicine Toolkit. A table summarizing the potential mechanisms of action for N-acetylcysteine in these conditions is presented. Main Message. N-acetylcysteine may be useful as an adjuvant in treating various medical conditions, especially chronic diseases. These conditions include polycystic ovary disease, male infertility, sleep apnea, acquired immune deficiency syndrome, influenza, parkinsonism, multiple sclerosis, peripheral neuropathy, stroke outcomes, diabetic neuropathy, Crohn's disease, ulcerative colitis, schizophrenia, bipolar illness, and obsessive compulsive disorder; it can also be useful as a chelator for heavy metals and nanoparticles. There are also a number of other conditions that may show benefit; however, the evidence is not as robust.

CONCLUSION

The use of N-acetylcysteine should be considered in a number of conditions as our population ages and levels of glutathione drop. Supplementation may contribute to reducing morbidity and mortality in some chronic conditions as outlined in the article.

N-acetylcysteine, xCT and suppression of Maxi-chloride channel activity in human placenta

INTRODUCTION

Placental oxidative stress features in pregnancy pathologies but in clinical trials antioxidant supplementation has not improved outcomes. N-acetylcysteine (NAC) stimulates glutathione production and is proposed as a therapeutic agent in pregnancy. However, key elements of N-acetylcysteine biology, including its cellular uptake mechanism, remains unclear. This study explores how the cystine/glutamate transporter xCT may mediate N-acetylcysteine uptake and how N-acetylcysteine alters placental redox status.

METHODS

The involvement of xCT in NAC uptake by the human placenta was studied in perfused placenta and Xenopus oocytes. The effect of short-term N-acetylcysteine exposure on the placental villous proteome was determined using LC-MS. The effect of N-acetylcysteine on Maxi-chloride channel activity was investigated in perfused placenta, villous fragments and cell culture.

RESULTS

Maternoplacental N-acetylcysteine administration stimulated intracellular glutamate efflux suggesting a role of the exchange transporter xCT, which was localised to the microvillous membrane of the placental syncytiotrophoblast. Placental exposure to a bolus of N-acetylcysteine inhibited subsequent activation of the redox sensitive Maxi-chloride channel independently of glutathione synthesis. Stable isotope quantitative proteomics of placental villi treated with N-acetylcysteine demonstrated changes in pathways associated with oxidative stress, apoptosis and the acute phase response.

DISCUSSION

This study suggests that xCT mediates N-acetylcysteine uptake into the placenta and that N-acetylcysteine treatment of placental tissue alters the placental proteome while regulating the redox sensitive Maxi-chloride channel. Interestingly N-acetylcysteine had antioxidant effects independent of the glutathione pathway. Effective placental antioxidant therapy in pregnancy may require maintaining the balance between normalising redox status without inhibiting physiological redox signalling.

Induced Cell Death as a Possible Pathway of Antimutagenic Action

The existing concepts of antimutagenesis are briefly reviewed. Published reports on antimutagenic and proapoptotic properties of some polyphenols and compounds of other chemical groups obtained in representative in vitro and in vivo experiments on eukaryotic test systems are discussed. The relationships between the antimutagenic and proapoptotic properties of the analyzed compounds (naringin, apigenin, resveratrol, curcumin, N-acetylcysteine, etc.) are considered in favor of the hypothesis on induced cell death as an antimutagenic tool.

Dietary Antioxidants Significantly Reduced Phorbol Myristate Acetate Induced Oxidative Stress of Peripheral Blood Mononuclear Cells of Patients with Rheumatoid Arthritis

BACKGROUND

Rheumatoid arthritis (RA) is an autoimmune disease responsible for maximum human morbidity in modern life, whereas oxidative stress is the ultimate potential biomarker for determining disease activity in patients with RA.

OBJECTIVE

The present study scientifically validated the effectiveness of antioxidants commonly present in different food supplements to neutralize the free radicals mediated oxidative stress in isolated peripheral blood mononuclear lymphocytes (PBML) of patients with RA.

METHODS

The study population included patients with Rheumatoid arthritis, RA (n =15), who fulfilled the American College of Rheumatology criteria for RA. Peripheral blood was collected, and isolated mononuclear lymphocyte cells (PBML) were pretreated with phorbol myristate acetate (PMS) and furthermore, incubated with different concentrations of Naringenin, β carotene and Nacetyl cysteine (NAC) in an ex vivo condition. The resultant cell lysate was used for further studies for the determination of other oxidative biomarkers. The increase of superoxide and nitric oxide production was observed when PBML was treated PMS.

RESULTS

Importantly, the increased oxidative stress was effectively decreased by the selected plantderived compounds β-carotene and naringenin.

CONCLUSION

The study scientifically evaluated the efficacy of the molecules validated by one-way ANOVA, followed by Dunnett's post hoc test of significance. Collectively, our results indicate that both β carotene and naringenin may be a promising non-toxic food supplement in attenuating the oxidative stress associated pathology in RA, meriting further pharmacological studies on other inflammatory cells like neutrophils.

Dissecting the mechanism of temozolomide resistance and its association with the regulatory roles of intracellular reactive oxygen species in glioblastoma

Glioblastoma is the most common primary malignant brain tumor that is usually considered fatal even with treatment. This is often a result for tumor to develop resistance. Regarding the standard chemotherapy, the alkylating agent temozolomide is effective in disease control but the recurrence will still occur eventually. The mechanism of the resistance is various, and differs in terms of innate or acquired. To date, aberrations in O⁶-methylguanine-DNA methyltransferase are the clear factor that determines drug susceptibility. Alterations of the other DNA damage repair genes such as DNA mismatch repair genes are also known to affect the drug effect. Together these genes have roles in the innate resistance, but are not sufficient for explaining the mechanism leading to acquired resistance. Recent identification of specific cellular subsets with features of stem-like cells may have role in this process. The glioma stem-like cells are known for its superior ability in withstanding the drug-induced cytotoxicity, and giving the chance to repopulate the tumor. The mechanism is complicated to administrate cellular protection, such as the enhancing ability against reactive oxygen species and altering energy metabolism, the important steps to survive. In this review, we discuss the possible mechanism for these specific cellular subsets to evade cancer treatment, and the possible impact to the following treatment courses. In addition, we also discuss the possibility that can overcome this obstacle.

Aptamer-SH2 superbinder-based targeted therapy for pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) exhibits the poorest prognosis of all solid tumors with a 5-year survival rate of less than 10% and a median survival of 6 months after diagnosis. Numerous targeted agents have been developed and evaluated to improve the survival benefit in patients with PDAC. Unfortunately, most agents have been proven futile mainly owing to the dense stroma and the sophisticated signaling pathways of PDAC. Here, we show the potent effectiveness of Aptamer-SH2 superbinder-(Arg)9 conjugate on the treatment of PDAC. In this conjugate, DNA aptamer selected against PDAC cell line confers the function of specifically recognizing and binding to the PDAC cells and activated pancreatic stellate cells (PSCs) in stroma; cell penetrating peptide (Arg)9 facilitates the intracellular delivery of fused proteins; SH2 superbinder conducts the drastic blockade of multiple phosphotyrosines (pY)-based signaling pathways in tumor cells.

METHODS

PDAC-associated pY were reanalyzed by bioinformatics screen. XQ-2d and SH2 superbinder-(Arg)9 were crosslinked with BMH to form XQ-2d-SH2 CM-(Arg)9 conjugate. Immunofluorescence was utilized to assess the potency of the conjugate entering cells. MTT and wound healing assays were performed to evaluate the proliferation or migration of PANC-1 and BxPC-3 cells, respectively. Western blot and Pulldown assays revealed that conjugate influenced several pY-based signaling pathways. Tumor-bearing mice were used to validate XQ-2d-SH2 CM-(Arg)9, which restrained the growth and metastasis of cancer cells.

RESULTS

XQ-2d-His-SH2 CM-(Arg)9 conjugate restrained proliferation, invasion, and metastasis of PDAC cells with potent efficacy via blocking the activity of several pY-related signaling cascades. XQ-2d-His-SH2 CM-(Arg)9 could eliminate the dense stroma of PDAC and then arrive at tumor tissues.

CONCLUSIONS

XQ-2d-SH2 CM-(Arg)9 conjugate may efficiently destroy the pancreatic stroma and show potent antitumor efficacy with minimal toxic effect by regulating tumor cell proliferation and metastasis in vitro and in vivo, which makes it to be a promising targeted therapy of PDAC.

Arginine Deiminase Induces Immunogenic Cell Death and Is Enhanced by N-acetylcysteine in Murine MC38 Colorectal Cancer Cells and MDA-MB-231 Human Breast Cancer Cells In Vitro

The use of arginine deiminase (ADI) for arginine depletion therapy is an attractive anticancer approach. Combination strategies are needed to overcome the resistance of severe types of cancer cells to this monotherapy. In the current study, we report, for the first time, that the antioxidant N-acetylcysteine (NAC), which has been used in therapeutic practices for several decades, is a potent enhancer for targeted therapy that utilizes arginine deiminase. We demonstrated that pegylated arginine deiminase (ADI-PEG 20) induces apoptosis and G0/G1 phase arrest in murine MC38 colorectal cancer cells; ADI-PEG 20 induces Ca2+ overload and decreases the mitochondrial membrane potential in MC38 cells. ADI-PEG 20 induced the most important immunogenic cell death (ICD)-associated feature: cell surface exposure of calreticulin (CRT). The antioxidant NAC enhanced the antitumor activity of ADI-PEG 20 and strengthened its ICD-associated features including the secretion of high mobility group box 1 (HMGB1) and adenosine triphosphate (ATP). In addition, these regimens resulted in phagocytosis of treated MC38 cancer cells by bone marrow-derived dendritic cells (BMDCs). In conclusion, we describe, for the first time, that NAC in combination with ADI-PEG 20 not only possesses unique cytotoxic anticancer properties but also triggers the hallmarks of immunogenic cell death. Hence, ADI-PEG 20 in combination with NAC may represent a promising approach to treat ADI-sensitive tumors while preventing relapse and metastasis.

LKB1-MARK2 signalling mediates lipopolysaccharide-induced production of cytokines in mouse macrophages

Lipopolysaccharide (LPS) is an endotoxin involved in a number of acute and chronic inflammatory syndromes. Although LPS-induced signalling has been extensively studied, there are still mysteries remaining to be revealed. In the current study, we used high-throughput phosphoproteomics to profile LPS-initiated signalling and aimed to find novel mediators. A total of 448 phosphoproteins with 765 phosphorylation sites were identified, and we further validated that the phosphorylation of MARK2 on T208 was important for the regulation on LPS-induced CXCL15 (human IL-8 homolog), IL-1β, IL-6 and TNF-α release, in which LKB1 had a significant contribution. In summary, induction of cytokines by LPS in mouse macrophage is regulated by LKB1-MARK2 signals. Our study provides new clues for further exploring the underlying mechanisms of LPS-induced diseases, and new therapeutic approaches concerning bacterial infection may be derived from these findings.

A brief overview of clinical significance of novel Notch2 regulators

The Notch pathway is an essential signaling system allowing neighboring cells to communicate and accomplish their proper developmental role in physiological condition. Nevertheless, there are many controversies conferring its function in pathological condition, particularly in cancer. It has been discovered that epigenetic regulation, posttranslational modifications, gene overexpression, and mutations may lead to the dysregulation of the Notch pathway. Additionally, Notch-mediated signaling can support tumor-suppressing mechanisms in certain types of cancer or may have oncogenic functions in others. Notch2 is one of the receptors commonly expressed in a variety of cancer cells, including gastric, hematological, and lung cancer. Moreover, it can be dysregulated in other diseases. In efforts to explain the role of Notch2 in the pathogenesis of cancer, recent studies indicated an association between this receptor and dysregulation of miRNAs, tumor-associated stromal cell, and modulation in tumor cells. Consequently, Notch2 function in the carcinogenesis process is unquestionable, whereas information according to the effect of its inhibition in tumor is still obscure. Hence, the aim of our study was to evaluate the current state of knowledge conferring Notch2 inhibition, with a particular focus on its role in cancer.

Wenxin Granule Ameliorates Hypoxia/Reoxygenation-Induced Oxidative Stress in Mitochondria via the PKC-δ/NOX2/ROS Pathway in H9c2 Cells

Myocardial infarction and following reperfusion therapy-induced myocardial ischemia/reperfusion (I/R) injury have been recognized as an important subject of cardiovascular disease with high mortality. As the antiarrhythmic agent, Wenxin Granule (WXG) is widely used to arrhythmia and heart failure. In our pilot study, we found the antioxidative potential of WXG in the treatment of myocardial I/R. This study is aimed at investigating whether WXG could treat cardiomyocyte hypoxia/reoxygenation (H/R) injury by inhibiting oxidative stress in mitochondria. The H9c2 cardiomyocyte cell line was subject to H/R stimuli to mimic I/R injury in vitro. WXG was added to the culture medium 24 h before H/R exposing as pretreatment. Protein kinase C-δ (PKC-δ) inhibitor rottlerin or PKC-δ lentivirus vectors were conducted on H9c2 cells to downregulate or overexpress PKC-δ protein. Then, the cell viability, oxidative stress levels, intracellular and mitochondrial ROS levels, mitochondrial function, and apoptosis index were analyzed. In addition, PKC-δ protein expression in each group was verified by western blot analysis. Compared with the control group, the PKC-δ protein level was significantly increased in the H/R group, which was remarkably improved by WXG or rottlerin. PKC-δ lentivirus vector-mediated PKC-δ overexpression was not reduced by WXG. WXG significantly improved H/R-induced cell injury, lower levels of SOD and GSH/GSSG ratio, higher levels of MDA, intracellular and mitochondrial ROS content, mitochondrial membrane potential and ATP loss, mitochondrial permeability transition pore opening, NOX2 activation, cytochrome C release, Bax/Bcl-2 ratio and cleaved caspase-3 increasing, and cell apoptosis. Similar findings were obtained from rottlerin treatment. However, the protective effects of WXG were abolished by PKC-δ overexpression, indicating that PKC-δ was a potential target of WXG treatment. Our findings demonstrated a novel mechanism by which WXG attenuated oxidative stress and mitochondrial dysfunction of H9c2 cells induced by H/R stimulation via inhibitory regulation of PKC-δ/NOX2/ROS signaling.

Matrine inhibits the development and progression of ovarian cancer by repressing cancer associated phosphorylation signaling pathways

Ovarian cancer remains the most lethal gynecologic malignancy with late detection and acquired chemoresistance. Advanced understanding of the pathophysiology and novel treatment strategies are urgently required. A growing body of proteomic investigations suggest that phosphorylation has a pivotal role in the regulation of ovarian cancer associated signaling pathways. Matrine has been extensively studied for its potent anti-tumor activities. However, its effect on ovarian cancer cells and underlying molecular mechanisms remain unclear. Herein we showed that matrine treatment inhibited the development and progression of ovarian cancer cells by regulating proliferation, apoptosis, autophagy, invasion and angiogenesis. Matrine treatment retarded the cancer associated signaling transduction by decreasing the phosphorylation levels of ERK1/2, MEK1/2, PI3K, Akt, mTOR, FAK, RhoA, VEGFR2, and Tie2 in vitro and in vivo. Moreover, matrine showed excellent antitumor effect on chemoresistant ovarian cancer cells. No obvious toxic side effects were observed in matrine-administrated mice. As the natural agent, matrine has the potential to be the targeting drug against ovarian cancer cells with the advantages of overcoming the chemotherapy resistance and decreasing the toxic side effects.

miR-140-5p mediates bevacizumab-induced cytotoxicity to cardiomyocytes by targeting the VEGFA/14-3-3γ signal pathway

Bevacizumab (BVZ) is the first recombinant humanized monoclonal antibody against vascular endothelial growth factor (VEGFA) approved by the FDA for the treatment of different kinds of cancers, especially colorectal cancer. Although the anti-tumor effects have been verified, the side effects of BVZ are also noteworthy, among which, cardiotoxicity may be the most serious side effect of BVZ. However, the exact mechanisms of cardiotoxicity induced by BVZ have been little explored. This study was conducted in vitro in a human cardiac myocyte (HCM) model. MTT assay was conducted to determine BVZ-stimulated cell viability. For testing the function and mechanism, the cells were transfected with miR-140-5p mimics, miR-140-5p inhibitor and/or VEGFA small interfering RNA (si-VEGFA). Then, apoptosis of the cells was detected via annexin V/propidium iodide (AV-PI) staining followed by flow cytometry. qRT-PCR and western blot assays were applied to measure gene expression (i.e. mRNA) and protein levels, respectively. The CK, LDH, SOD, CAT and GSH-Px activities and MDA level were determined using commercial kits. ROS levels were determined by DCFH-DA assay. Mitochondrial membrane potential was measured by JC-1 assay. Dual-luciferase reporter assay was used to detect the interaction between miR-140-5p and VEGFA. BVZ could inhibit HCM proliferation and induce apoptosis. miR-140-5p was upregulated in response to BVZ treatment and miR-140-5p restraint could alleviate HCM damage caused by BVZ treatment. In contrast, VEGFA and 14-3-3γ expressions were down-regulated by BVZ, and miR-140-5p could inhibit the expression of 14-3-3γ by directly targeting VEGFA. Moreover, VEGFA suppression enhanced HCM injury stimulated by BVZ and partially reversed the functional role of the miR-140-5p inhibitor in BVZ-treated cells. Taken together, miR-140-5p promoted BVZ-treated cardiomyocyte toxicity by targeting the VEGFA/14-3-3γ signal pathway. Collectively, miR-140-5p mediated the BVZ-induced cytotoxicity to cardiomyocytes by targeting the VEGFA/14-3-3γ signal pathway, indicating that miR-140-5p may be a novel target for treating BVZ-induced cardiotoxicity.

The role of oncogenic Notch2 signaling in cancer: a novel therapeutic target

Deregulated Notch signaling is a key factor thought to facilitate the stem-like proliferation of cancer cells, thereby facilitating disease progression. Four subtypes of Notch receptor have been described to date, with each playing a distinct role in cancer development and progression, therefore warranting a careful and comprehensive examination of the targeting of each receptor subtype in the context of oncogenesis. Clinical efforts to translate the DAPT, which blocks Notch signaling, have been unsuccessful due to a combination of serious gastrointestinal side effects and a lack of complete blocking efficacy. There is therefore a clear need to identify better therapeutic strategies for targeting and manipulating Notch signaling. Notch2 is a Notch receptor that is commonly overexpressed in a range of cancers, and which is linked to a unique oncogenic mechanism. Successful efforts to block Notch2 signaling will depend upon doing so both efficiently and specifically in patients. As such, in the present review we will explore the role of Notch2 signaling in the development and progression of cancer, and we will assess agents and strategies with the potential to effectively disrupt Notch2 signaling and thereby yield novel cancer treatment regimens.

miR-4739 mediates pleural fibrosis by targeting bone morphogenetic protein 7

BACKGROUND

Pleural fibrosis is defined as excessive depositions of matrix components that result in pleural tissue architecture destruction and dysfunction. In severe cases, the progression of pleural fibrosis leads to lung entrapment, resulting in dyspnea and respiratory failure. However, the mechanism of pleural fibrosis is poorly understood.

METHODS

miR-4739 levels were detected by miRNA array and real-time PCR. Real-time PCR, western blotting and immunofluorescence were used to identify the expression profile of indicators related to fibrosis. Target gene of miR-4739 and promoter activity assay was measured by using dual-luciferase reporter assay system. In vivo, pleural fibrosis was evaluated by Masson staining and miR-4739 level was detected by In situ hybridization histochemistry.

FINDINGS

We found that bleomycin induced up-regulation of miR-4739 in pleural mesothelial cells (PMCs). Over-regulated miR-4739 mediated mesothelial-mesenchymal transition and increased collagen-I synthesis in PMCs. Investigation on the clinical specimens revealed that high levels of miR-4739 and low levels of bone morphogenetic protein 7 (BMP-7) associated with pleural fibrosis in patients. Then we next identified that miR-4739 targeted and down-regulated BMP-7 which further resulted in unbalance between Smad1/5/9 and Smad2/3 signaling. Lastly, in vivo studies revealed that miR-4739 over-expression induced pleural fibrosis, and exogenous BMP-7 prevented pleural fibrosis in mice.

INTERPRETATION

Our data indicated that miR-4739 targets BMP-7 which mediates pleural fibrosis. The miR-4739/BMP-7 axis is a promising therapeutic target for the disease. FUND: The National Natural Science Foundation of China.