ROS inhibitor N-acetyl-L-cysteine antagonizes the activity of proteasome inhibitors

N-Acetyl-l-cysteine Enhances the Effect of Selenium Nanoparticles on Cancer Cytotoxicity by Increasing the Production of Selenium-Induced Reactive Oxygen Species

Peritoneal carcinomatosis (PC) has an extremely poor prognosis, which leads to a significantly decreased overall survival in patients with peritoneal implantation of cancer cells. Administration of sodium selenite by intraperitoneal injection is highly effective in inhibiting PC. Our previous study found that selenium nanoparticles (SeNPs) have higher redox activity and safety than sodium selenite. In the present study, we examined the therapeutic effect of SeNPs on PC and elucidated the potential mechanism. Our results revealed that intraperitoneal delivery of SeNPs to cancer cells in the peritoneal cavity of mice at a tolerable dose was beneficial for prolonging the survival time of mice, even better than the optimal dose of cisplatin. The underlying mechanism involved in SeNP-induced reactive oxygen species (ROS) production caused protein degradation and apoptotic response in cancer cells. Interestingly, N-acetyl-l-cysteine (NAC), recognized as a ROS scavenger, without reducing the efficacy of SeNPs, enhanced ROS production and cytotoxicity. The effect of NAC was associated with the following mechanisms: (1) the thiol groups in NAC can increase the biosynthesis of endogenous glutathione (GSH), thus increasing the production of SeNP-induced ROS and cytotoxicity and (2) redox cycling of SeNPs was directly driven by thiol groups in NAC to produce ROS. Moreover, NAC, without increasing the systematic toxicity of SeNPs, decreased SeNP-induced lethality in healthy mice. Overall, we demonstrated that SeNPs exert a potential cytotoxicity effect by inducing ROS production in cancer cells; NAC effectively heightens the property of SeNPs in vitro and in vivo.

DFIQ, a Novel Quinoline Derivative, Shows Anticancer Potential by Inducing Apoptosis and Autophagy in NSCLC Cell and In Vivo Zebrafish Xenograft Models

Lung cancer is one of the deadliest cancers worldwide due to chemoresistance in patients with late-stage disease. Quinoline derivatives show biological activity against HIV, malaria, bacteriuria, and cancer. DFIQ is a novel synthetic quinoline derivative that induces cell death in both in vitro and in vivo zebrafish xenograft models. DFIQ induced cell death, including apoptosis, and the IC₅₀ values were 4.16 and 2.31 μM at 24 and 48 h, respectively. DFIQ was also found to induce apoptotic protein cleavage and DNA damage, reduce cell cycle-associated protein expression, and disrupt reactive oxygen species (ROS) reduction, thus resulting in the accumulation of superoxide radicals. Autophagy is also a necessary process associated with chemotherapy-induced cell death. Lysosome accumulation and lysosome-associated membrane protein-2 (LAMP2) depletion were observed after DFIQ treatment, and cell death induction was restored upon treatment with the autophagy inhibitor 3-methyladenine (3-MA). Nevertheless, ROS production was found to be involved in DFIQ-induced autophagy activation and LAMP2 depletion. Our data provide the first evidence for developing DFIQ for clinical usage and show the regulatory mechanism by which DFIQ affects ROS, autophagy, and apoptosis.

Redox Modulation and Induction of Ferroptosis as a New Therapeutic Strategy in Hepatocellular Carcinoma

Ferroptosis, a newly discovered form of cell death mediated by reactive oxygen species (ROS) and lipid peroxidation, has recently been shown to have an impact on various cancer types; however, so far there are only few studies about its role in hepatocellular carcinoma (HCC). The delicate equilibrium of ROS in cancer cells has found to be crucial for cell survival, thus increased levels may trigger ferroptosis in HCC. In our study, we investigated the effect of different ROS modulators and ferroptosis inducers on a human HCC cell line and a human hepatoblastoma cell line. We identified a novel synergistic cell death induction by the combination of Auranofin and buthionine sulfoxime (BSO) or by Erastin and BSO at subtoxic concentrations. We found a caspase-independent, redox-regulated cell death, which could be rescued by different inhibitors of ferroptosis. Both cotreatments stimulated lipid peroxidation. All these findings indicated ferroptotic cell death. Both cotreatments affected the canonical ferroptosis pathway through GPX4 downregulation. We also found an accumulation of Nrf2 and HO-1, indicating an additional effect on the non-canonical pathway. Our results implicate that targeting these two main ferroptotic pathways simultaneously can overcome chemotherapy resistance in HCC.

Blueberry-Derived Exosome-Like Nanoparticles Counter the Response to TNF-α-Induced Change on Gene Expression in EA.hy926 Cells

Exosome-like nanoparticles (ELNs) are attracting interest as important vehicles of intercellular communication, both in prokaryotes and eukaryotes. Recently, dietary nanoparticles similar to mammalian exosomes have attracted attention for these features. In particular they appear to be relevant in the modulation of several cellular processes as well as candidate carriers of bioactive molecules (proteins, lipids, and nucleic acids, including miRNAs) with therapeutic value. Herein, we investigated the cellular uptake of blueberry-derived ELNs (B-ELNs) by a human stabilized endothelial cell line (EA.hy926) and the ability of B-ELNs to modulate the expression of inflammatory genes as the response of tumor necrosis factor-α (TNF-α). Our results indicate that 1) EA.hy926 cells internalize B-ELNs in a dose-dependent manner; 2) pretreatment with B-ELNs counters TNF-α-induced reactive oxygen species (ROS) generation and loss of cell viability and modulates the differential expression of 29 genes (fold change > 1.5) induced by TNF-α compared to control; 3) pathway analysis reveals their involvement in a total of 340 canonical pathways, 121 KEGG pathways, and 121 GO Biological processes; and 4) the intersection between differentially expressed (DE) genes and miRNAs contained in B-ELNs unveils a set of candidate target genes, such as prostaglandin I2 synthase (PTGIS), mitogen-activated protein kinase 14 (MAPK14), and phosphodiesterase 7A (PDE7A), for ELNs-contained cargo. In conclusion, our study indicates that B-ELNs can be considered candidate therapeutic carriers of bioactive compounds potentially able to protect vascular system against various stressors.

MiR-138 Suppresses the PDK1 Expression to Decrease the Oxaliplatin Resistance of Colorectal Cancer

Background

Oxaliplatin is one kind of platinum-based drug. It is effective and commonly used in the treatment of colorectal cancer (CRC). However, development of acquired drug resistance is still a big obstacle during the oxaliplatin therapy. It is urgent to take strategies to decrease the oxaliplatin resistance of CRC.

Materials and Methods

Oxaliplatin-resistant HT29 and SW480 (HT29/R and SW480/R) cells were acquired through long-term exposure to oxaliplatin by using the routine HT29 and SW480 cells. Relative glucose consumption, lactate generation and LDH activity were tested to evaluate the glycolysis of CRC cell lines. MTT assays were conducted to evaluate the differences of oxaliplatin sensitivity between HT29/R (SW480/R) cells and their parental HT29 (SW480) cells. Regulation of miR-138 on PDK1 was confirmed through qRT-PCR, Western blot and dual-luciferase reporter assays. Reactive oxygen species (ROS) levels were measured by flow cytometry.

Results

HT29/R and SW480/R cells exhibited higher glucose consumption, lactate production and LDH activity compared to their parental HT29 and SW480 cells. However, oxygen consumption rate (OCR) in HT29/R and SW480/R cells is lower than that in HT29 and SW480 cells, respectively. Results of MTT assays showed that treatment with miR-138 can increase the cytotoxicity of oxaliplatin to HT29/R and SW480/R cells. Research on mechanisms showed that PDK1 was the target of miR-138. Overexpression of miR-138 can inhibit the expression of PDK1, and thus increase the OCR of HT29/R and SW480/R cells. Under the treatment of oxaliplatin, the miR-138-overexpressed HT29/R and SW480/R cells generated more amount of ROS to get into the apoptosis process.

Conclusion

Overexpression of miR-138 suppressed the PDK1 expression to decrease the oxaliplatin resistance of CRC.

Oxidative Stress Induction Is a Rational Strategy to Enhance the Productivity of Antrodia cinnamomea Fermentations for the Antioxidant Secondary Metabolite Antrodin C

Antioxidant metabolites contribute to alleviating oxidative stress caused by reactive oxygen species (ROS) in microorganisms. We utilized oxidative stressors such as hydrogen peroxide supplementation to increase the yield of the bioactive secondary metabolite antioxidant antrodin C in submerged fermentations of the medicinal mushroom Antrodia cinnamomea. Changes in the superoxide dismutase and catalase activities of the cells indicate that ROS are critical to promote antrodin C biosynthesis, while the ROS production inhibitor diphenyleneiodonium cancels the productivity-enhancing effects of H2O2. Transcriptomic analysis suggests that key enzymes in the mitochondrial electron transport chain are repressed during oxidative stress, leading to ROS accumulation and triggering the biosynthesis of antioxidants such as antrodin C. Accordingly, rotenone, an inhibitor of the electron transport chain complex I, mimics the antrodin C productivity-enhancing effects of H2O2. Delineating the steps connecting oxidative stress with increased antrodin C biosynthesis will facilitate the fine-tuning of strategies for rational fermentation process improvement.

Anti-oxidant and anti-inflammatory effects of auraptene on phytohemagglutinin (PHA)-induced inflammation in human lymphocytes

BACKGROUND

Inflammation is characterized as a defensive response of our body against endogenous or exogenous stimuli. Chronic inflammation and oxidative stress play an important role in the pathogenesis of various disorders such as asthma, cancers, and multiple sclerosis. Recently, diverse pharmacological activities of auraptene, a natural prenyloxycoumarin, were reported. In the present study, we aimed to evaluate the anti-oxidative and anti-inflammatory effects of auraptene on human isolated lymphocytes.

METHOD

The effects of auraptene (10, 30 and 90 μM) and dexamethasone (0.1 mM) were evaluated on cell viability, reactive oxygen species (ROS), and malondialdehyde (MDA) levels, superoxide dismutase (SOD) and catalase (CAT) activities, and total glutathione content (GSH) as well as the secretion of interleukin 6 (IL-6) and tumor necrosis factor (TNF)-α in phytohemagglutinin (PHA)-stimulated human lymphocytes.

RESULTS

Auraptene (10-90 μM) did not affect lymphocytes' viability after 48 h incubation. PHA markedly elevated ROS, MDA, IL-6, and TNF-α levels, while diminished the GSH content, and CAT and SOD activities in human lymphocytes (p < 0.001 for all cases). Treatment with auraptene (10-90 µM) significantly ameliorated ROS, MDA, IL-6, and TNF-α levels, and markedly increased GSH content, and CAT and SOD activities (p <  0.5-0.001).

CONCLUSION

Auraptene may possess promising healing effects in the different inflammatory disorders associated with activation of the acquired immune system such as multiple sclerosis and asthma.

Sirtuin 1 inhibits lipopolysaccharide-induced inflammation in chronic myelogenous leukemia k562 cells through interacting with the Toll-like receptor 4-nuclear factor κ B-reactive oxygen species signaling axis

Background

Chronic myelogenous leukemia (CML) is a clonal myeloproliferative neoplasm resulting from BCR–ABL-transformed hematopoietic stem cells. Previous research has implicated multifunctional proinflammatory cytokines in CML development. It has been reported that Sirtuin 1 (SIRT1) as well as ADP-ribosyltransferase and deacetylase may influence CML cell viability and inflammation.

Methods

This study was directed toward exploring the SIRT1-involved in the mechanism of lipopolysaccharide (LPS)-triggered inflammation in CML k562 cells.

Results

In our study, the LPS-induced inflammation in k562 cells was reflected by increases in levels of diverse inflammatory cytokines, including interleukin (IL)-10, IL-1β, IL-6, interferon-γ, tumor necrosis factor (TNF)-α and TNF-β. LPS also decreased SIRT1 expression and nuclear location in k562 cells. Furthermore, SIRT1 overexpression inhibited the release of the above mentioned cytokines in LPS-treated cells. We also determined that LPS stimulation could activate Toll-like receptor 4 (TLR4), the nuclear factor κ B (NFκB) subunit, and p65 and produce reactive oxygen species (ROS) in k562 cells. Nevertheless, SIRT1 overexpression decreased TLR4 expression, thereby repressing the phosphorylation of the NFκB subunit and p65 and decreasing ROS production.

Conclusions

These findings suggest that SIRT1 is a latent therapeutic target for mitigating LPS-induced inflammation via the TLR4–NFκB–ROS signaling axis.

Reactive Oxygen Species (ROS)-Responsive Polymersomes with Site-Specific Chemotherapeutic Delivery into Tumors via Spacer Design Chemistry

The lack of cellular and tissue specificities in conventional chemotherapies along with the generation of a complex tumor microenvironment (TME) limits the dosage of active agents that reaches tumor sites, thereby resulting in ineffective responses and side effects. Therefore, the development of selective TME-responsive nanomedicines is of due relevance toward successful chemotherapies, albeit challenging. In this framework, we have synthesized novel, ready-to-use ROS-responsive amphiphilic block copolymers (BCs) with two different spacer chemistry designs to connect a hydrophobic boronic ester-based ROS sensor to the polymer backbone. Hydrodynamic flow focusing nanoprecipitation microfluidics (MF) was used in the preparation of well-defined ROS-responsive PSs; these were further characterized by a combination of techniques [¹H NMR, dynamic light scattering (DLS), static light scattering (SLS), transmission electron microscopy (TEM), and cryogenic TEM (cryo-TEM)]. The reaction with hydrogen peroxide releases an amphiphilic phenol or a hydrophilic carboxylic acid, which affects polymersome (PS) stability and cargo release. Therefore, the importance of the spacer chemistry in BC deprotection and PS stability and cargo release is herein highlighted. We have also evaluated the impact of spacer chemistry on the PS-specific release of the chemotherapeutic drug doxorubicin (DOX) into tumors in vitro and in vivo. We demonstrate that by spacer chemistry design one can enhance the efficacy of DOX treatments (decrease in tumor growth and prolonged animal survival) in mice bearing EL4 T cell lymphoma. Side effects (weight loss and cardiotoxicity) were also reduced compared to free DOX administration, highlighting the potential of the well-defined ROS-responsive PSs as TME-selective nanomedicines. The PSs could also find applications in other environments with high ROS levels, such as chronic inflammations, aging, diabetes, cardiovascular diseases, and obesity.

Radiotracer Development for Bacterial Imaging

Bacterial infections remain a major threat to humanity and are a leading cause of death and disability. Antimicrobial resistance has been declared as one of the top ten threats to human health by the World Health Organization, and new technologies are urgently needed for the early diagnosis and monitoring of deep-seated and complicated infections in hospitalized patients. This review summarizes the radiotracers as applied to imaging of bacterial infections. We summarize the recent progress in the development of pathogen-specific imaging and the application of radiotracers in understanding drug pharmacokinetics as well as the local biology at the infection sites. We also highlight the opportunities for medicinal chemists in radiotracer development for bacterial infections, with an emphasis on target selection and radiosynthetic approaches. Imaging of infections is an emerging field. Beyond clinical applications, these technologies could provide unique insights into disease pathogenesis and expedite bench-to-bedside translation of new therapeutics.

Proteasomal inhibition triggers viral oncoprotein degradation via autophagy-lysosomal pathway

Epstein-Barr virus (EBV) nuclear oncoprotein EBNA3C is essential for B-cell transformation and development of several B-cell lymphomas particularly those are generated in an immuno-compromised background. EBNA3C recruits ubiquitin-proteasome machinery for deregulating multiple cellular oncoproteins and tumor suppressor proteins. Although EBNA3C is found to be ubiquitinated at its N-terminal region and interacts with 20S proteasome, the viral protein is surprisingly stable in growing B-lymphocytes. EBNA3C can also circumvent autophagy-lysosomal mediated protein degradation and subsequent antigen presentation for T-cell recognition. Recently, we have shown that EBNA3C enhances autophagy, which serve as a prerequisite for B-cell survival particularly under growth deprivation conditions. We now demonstrate that proteasomal inhibition by MG132 induces EBNA3C degradation both in EBV transformed B-lymphocytes and ectopic-expression systems. Interestingly, MG132 treatment promotes degradation of two EBNA3 family oncoproteins-EBNA3A and EBNA3C, but not the viral tumor suppressor protein EBNA3B. EBNA3C degradation induced by proteasomal inhibition is partially blocked when autophagy-lysosomal pathway is inhibited. In response to proteasomal inhibition, EBNA3C is predominantly K63-linked polyubiquitinated, colocalized with the autophagy-lysosomal fraction in the cytoplasm and participated within p62-LC3B complex, which facilitates autophagy-mediated degradation. We further show that the degradation signal is present at the first 50 residues of the N-terminal region of EBNA3C. Proteasomal inhibition reduces the colony formation ability of this important viral oncoprotein, induces apoptotic cell death and increases transcriptional activation of both latent and lytic gene expression which further promotes viral reactivation from EBV transformed B-lymphocytes. Altogether, this study offers rationale to use proteasome inhibitors as potential therapeutic strategy against multiple EBV associated B-cell lymphomas, where EBNA3C is expressed.

Light-triggered selective ROS-dependent autophagy by bioactive nanoliposomes for efficient cancer theranostics

Light-responsive nanoliposomes are being reported to induce cancer cell death through heat and reactive oxygen species (ROS). Nanoliposomes (CIR NLPs) encapsulating a near-infrared (NIR) light-sensitive dye, IR780, and a bioactive chlorophyll-rich fraction of Anthocephalus cadamba (CfAc) were synthesized and characterized. These CIR NLPs, when activated by NIR light, displayed localized synergistic cancer cell death under in vitro and in vivo conditions. We demonstrated a NIR light-mediated release of CfAc in cancer cells. The bioactive CfAc was selective in causing ROS generation (leading to autophagic cell death) in cancer cells, while normal healthy cells were unaffected. An increase in the intracellular ROS leading to enhanced lipidation of microtubule-associated protein light chain 3 (LC3-II) was observed only in cancer cells, while normal cells showed no increase in either ROS or LC3-II. In vivo analysis of CIR NLPs in an orthotopic mouse model showed better anti-tumorigenic potential through a combined effect (i.e. via heat and CfAc). We reported for the first time induction of selective and localized, bioactive phyto fraction-mediated autophagic cancer cell death through an NIR light trigger. The synergistic activation of ROS-mediated autophagy by light-triggered nanoliposomes can be a useful strategy for enhancing the anticancer potential of combinational therapies.

Visible-Light-Activated Molecular Nanomachines Kill Pancreatic Cancer Cells

Recently, synthetic molecular nanomachines (MNMs) that rotate unidirectionally in response to UV light excitation have been used to produce nanomechanical action on live cells to kill them through the drilling of holes in their cell membranes. In the work here, visible-light-absorbing MNMs are designed and synthesized to enable nanomechanical activation by 405 nm light, thereby using a wavelength of light that is less phototoxic than the previously employed UV wavelengths. Visible-light-absorbing MNMs that kill pancreatic cancer cells upon response to light activation are demonstrated. Evidence is presented to support the conclusion that MNMs do not kill cancer cells by the photothermal effect when used at low optical density. In addition, MNMs suppress the formation of reactive oxygen species, leaving nanomechanical action as the most plausible working mechanism for cell killing under the experimental conditions.

The compensatory antioxidant response system with a focus on neuroprogressive disorders

Major antioxidant responses to increased levels of inflammatory, oxidative and nitrosative stress (ONS) are detailed. In response to increasing levels of nitric oxide, S-nitrosylation of cysteine thiol groups leads to post-transcriptional modification of many cellular proteins and thereby regulates their activity and allows cellular adaptation to increased levels of ONS. S-nitrosylation inhibits the function of nuclear factor kappa-light-chain-enhancer of activated B cells, toll-like receptor-mediated signalling and the activity of several mitogen-activated protein kinases, while activating nuclear translocation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2 or NFE2L2); in turn, the redox-regulated activation of Nrf2 leads to increased levels and/or activity of key enzymes and transporter systems involved in the glutathione system. The Nrf2/Kelch-like ECH-associated protein-1 axis is associated with upregulation of NAD(P)H:quinone oxidoreductase 1, which in turn has anti-inflammatory effects. Increased Nrf2 transcriptional activity also leads to activation of haem oxygenase-1, which is associated with upregulation of bilirubin, biliverdin and biliverdin reductase as well as increased carbon monoxide signalling, anti-inflammatory and antioxidant activity. Associated transcriptional responses, which may be mediated by retrograde signalling owing to elevated hydrogen peroxide, include the unfolded protein response (UPR), mitohormesis and the mitochondrial UPR; the UPR also results from increasing levels of mitochondrial and cytosolic reactive oxygen species and reactive nitrogen species leading to nitrosylation, glutathionylation, oxidation and nitration of crucial cysteine and tyrosine causing protein misfolding and the development of endoplasmic reticulum stress. It is shown how these mechanisms co-operate in forming a co-ordinated rapid and prolonged compensatory antioxidant response system.

Anticancer and genotoxicity effect of (Clausena lansium (Lour.) Skeels) Peel ZnONPs on neuroblastoma (SH-SY5Y) cells through the modulation of autophagy mechanism

Nanotechnology is an emerged field to develop the plant mediated metal based nanodrugs by green method. In this current study, the zinc oxide metal based nanoparticles were developed using (Clausena lansium (Lour.) Skeels) Peel aqueous extracts and zinc nitrate. The C.L extract zinc nanoparticleswere indicated by the sharp peak seen at 350 nm utilizing the Ultraviolet-Visible spectroscopy (UV-Vis). The high peaks indicate the presence of phytochemicals and its functional groups in ZnONPs were studied by the Fourier Transform Infrared Spectroscopy (FT-IR). The X-Ray Diffraction analysis (XRD) explores the pattern and structure of ZnONPs as spherical and base-centered monoclinic crystalline shapes. The C.L extract with Zn nanoparticles were spherical in nature and the size of the synthesized particles were about 28.42 nm respectively. The autophagy (Beclin-1, LC3-I, LC3-II and ATG4B) and apoptotic (Bax, Bcl-2 and Caspase-3) proteins were regulated by the treatment with ZnONPs in SH-SY5Y neuroblastoma cells. The DNA loss or damage was occurred in the ZnONPs treatment and it was performed using Comet assay. The ZnONPs treatment generates the ROS in the cells and decreased its stability and viability. Addition of NAC prevents ROS in the cultured SH-SY5Y cells and prevents the cells from the apoptosis. We concluded that the ZnONPs potentially kills the neuroblastoma cells by producing the intracellular ROS.

N-Acetyl cysteine prevents activities of STAT3 inhibitors, Stattic and BP-1-102 independently of its antioxidant properties

BACKGROUND

Inhibitors for signal transducer and activator of transcription 3 (STAT3), Stattic, BP-1-102, and LLL12 significantly induce apoptosis in transformed Ba/F3 cells expressing an oncogenic fusion protein, nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) that induces the activation of STAT3. We found that the antioxidant reagent, N-acetyl cysteine (NAC) prevented the abilities of Stattic and BP-1-102, but not LLL12 to induce apoptosis in transformed cells expressing NPM-ALK, providing a novel problem in use of STAT3 inhibitors. We herein investigated the mechanisms how NAC prevented the effects of Sttatic and BP-1-102.

METHODS

Ba/F3 cells expressing NPM-ALK and SUDHL-1 cells were treated with antioxidants such as NAC, Trolox or edaravone in combination with STAT3 inhibitors. Phosphorylation of STAT3, cell proliferation rate, cell viability, cell cycle, internucleosomal DNA fragmentation and the intracellular accumulation of reactive oxygen species (ROS) was investigated. The binding of STAT3 inhibitors and NAC was analyzed by LC-MS.

RESULTS

NAC but not Trolox and edaravone diminished the abilities of Stattic and BP-1-102 to induce apoptosis in cells expressing NPM-ALK. The ROS levels in cells expressing NPM-ALK were not markedly affected by the treatments with Stattic and BP-1-102 in combination with NAC, suggesting that NAC inhibited the activity of Stattic and BP-1-102 independent of its antioxidant activity. LC-MS analysis revealed that NAC directly bound to Stattic and BP-1-102. Furthermore, these NAC adducts exhibited no cytotoxicity, and failed to affect the activity of STAT3.

CONCLUSIONS

NAC antagonizes the activities of Stattic and BP-1-102, which inhibit STAT3 activation by interacting with cysteine residues in STAT3.

Apoptotic lysosomal proton sponge effect in tumor tissue by cationic gold nanorods

Despite the lysosomal "proton sponge hypothesis" being considered to be an additional factor for stimulating the cellular toxicity of nanoparticle-based drug delivery systems, a clear relationship between the massive influx of calcium ions and the proton sponge effect, both of which are associated with cancer cell apoptosis, has still not been elucidated. Cetrimonium bromide (CTAB: cationic quaternary amino group based) gold nanorods possessed a more effective electric surface charge for inducing the lysosomal proton sponge effect than anionic gold nanoparticles. In this aspect, identifying released cytoplasmic Cl^-, arising from the ruptured lysosomal compartment, in the cytoplasm is critical for supporting the "proton sponge hypothesis". This study clarified that the burst release of Cl^-, as a result of lysosomal swelling by CTAB gold nanorods, stimulates the transient receptor potential channels melastatin 2 (TRPM2) channels, and subsequently induces a massive Ca²⁺ influx, which independently increases apoptosis of cancer cells. Although the previous concept of elevated cancer apoptosis acting through the proton sponge effect is unclear, this study supports the evidence that a massive Ca²⁺ influx mediated in response to a burst release of Cl^- significantly influenced cytotoxicity of cancer cells in tumor tissues.

Autophagy inhibition enhances Matrine derivative MASM induced apoptosis in cancer cells via a mechanism involving reactive oxygen species-mediated PI3K/Akt/mTOR and Erk/p38 signaling

Background

In the quest for new anti-cancer drugs, the drug discovery process has shifted to screening of active ingredients in traditional eastern medicine. Matrine is an active alkaloid isolated from plants of the Sophora genus used in traditional Chinese herbal medicine that exhibits a wide spectrum of biological properties and has a potential as an anti-proliferative agent. In this study, we investigated the anticancer property of MASM, ([(6aS, 10S, 11aR, 11bR, 11cS)210-Methylamino-dodecahydro-3a, 7a-diaza-benzo (de)anthracene-8-thione]), a potent derivative of matrine.

Methods

Four epithelial cancer cell lines representing the dominant cancers, namely: A549 (non-small-cell lung cancer cell line), MCF-7 and MDA-MB-231 (breast cancer cell lines), and Hela (cervical cancer cell line) were employed, and the mechanistic underpinning of MASM-induced apoptosis was investigated using flow cytometry, western blot and immunofluorescence.

Results

MASM, induced apoptosis via caspase 3 dependent and independent pathways, and autophagy in all the four cancer cell lines, but post-EMT (epithelial mesenchymal transition) cells showed greater sensitivity to MASM. Scavenging reactive oxygen species using N-acetylcysteine rescued all cancer cell lines from apoptosis and autophagy. Mechanistic analysis revealed that MASM induced autophagy involves inhibition of Akt signaling and the activation of Erk and p38 signaling, and inhibition of autophagy further enhanced the apoptosis induced by MASM.

Conclusions

These results indicate that MASM possesses potency against cancer cells and modulating autophagy during MASM administration could be used to further enhance its therapeutic effects.

Decitabine promotes apoptosis in mesenchymal stromal cells isolated from patients with myelodysplastic syndromes by inducing reactive oxygen species generation

Myelodysplastic syndromes (MDSs) are a group of clonal disorders of hematopoietic stem cells, resulting in ineffective hematopoiesis. Previous studies have reported that decitabine (DAC) plays an essential role in cell cycle arrest and cell death induction in multiple cell types. Nevertheless, the effect of decitabine on mesenchymal stromal cells derived from bone marrow of patients with MDSs is not completely clarified. Here, we explored the apoptotic and anti-proliferative effect of DAC on MSCs isolated from patients with MDSs. Treatment with DAC inhibited cell growth in a concentration- and time-dependent manner by inducing apoptosis. We found a positive relationship between cell death triggered by DAC in MSCs and the death receptor family members Fas and FasL mRNA and protein levels (***P < 0.00085), cleaved caspase (-3, -8, and -9) activity, and mitochondrial membrane potential reduction. Additionally, DAC-induced apoptosis was inhibited by Kp7-6, a FasL/Fas antagonist, indicating a crucial role of FasL/Fas, a cell death receptor, in mediating the apoptotic effect of DAC. DAC also induced reactive oxygen species (ROS) generation in MSCs derived from MDSs patients (*P = 0.038). Furthermore, N-acetyl-L-cysteine (NAC), a widely accepted ROS scavenger, efficiently reversed DAC-induced apoptosis by inhibiting ROS generation (***P < 0.00051) in mitochondria and restoring mitochondrial membrane potential. Furthermore, ROS production was found to be a consequence of caspase activation via caspases inhibition. Our data imply that DAC triggers ROS production in human MSCs, which serves as a crucial factor for mitochondrial membrane potential reduction, and DAC induces cell death prior to FasL/Fas stimulation.

Apoptotic and DNA-damaging effects of yttria-stabilized zirconia nanoparticles on human skin epithelial cells

Background

Yttria-stabilized zirconia (Y₂O_3/ZrO₂) nanoparticles are one of the important nanoparticles extensively used in manufacturing of plastics, textiles, catalyst, etc. Still, the cytotoxic and apoptotic effects of yttria-stabilized zirconia nanoparticles have not been well identified on human skin keratinocyte (HaCaT) cells. Therefore, in this study, we have designed to examine the cytotoxic potential of yttria-stabilized zirconia nanoparticles in HaCaT cells.

Methods

Prior to treatment, the yttria-stabilized zirconia nanoparticles were characterized by using different advanced instruments viz. dynamic light scattering (DLS), scanning electron microscope (SEM) and transmission electron microscope (TEM). Cell viability of HaCaT cells was measured by using MTS and NRU assays and viability of cells was reduced in a dose- and time-dependent manner.

Results

Reduction in the viability of cells was correlated with the rise of reactive oxygen species generation, increased caspase-3, mitochondria membrane potential and evidence of DNA strand breakage. These were consistent with the possibility that mitochondria damage can play a significant role in the cytotoxic response. Moreover, the activity of oxidative enzymes such as lipid peroxide (LPO) was increased and glutathione was reduced in HaCaT cells exposed with yttria-stabilized zirconia nanoparticles. It is also important to indicate that HaCaT cells appear to be more susceptible to yttria-stabilized zirconia nanoparticles exposure after 24 hrs.

Conclusion

This result provides a dose- and time-dependent apoptosis and genotoxicity of yttria-stabilized zirconia nanoparticles in HaCaT cells.

Tumor-Specific Expansion of Oxidative Stress by Glutathione Depletion and Use of a Fenton Nanoagent for Enhanced Chemodynamic Therapy

Amplifying intracellular oxidative stress effectively destroys cancer cells. In addition, iron-mediated Fenton reaction converts endogenous H₂O₂ to produce hypertoxic hydroxyl radical (^•OH), resulting in irreversible oxidative damage to combat tumor cells. This method is known as chemodynamic therapy (CDT). Overexpressed glutathione (GSH) in tumor cells efficiently scavenges ^•OH, significantly reducing the curative effects of CDT. To overcome this challenge and enhance intracellular oxidative stress, iron oxide nanocarriers loaded with β-lapachone (Lapa) drugs (Fe₃O₄-HSA@Lapa) were constructed and had both Fenton-like agents and GSH depletion properties to amplify intracellular oxidative stress. Release of Lapa selectively increases tumor site-specific generation of H₂O₂ via NAD(P)H: quinone oxidoreductase 1 (NQO1) catalysis. Subsequently, the iron ions released from the ionization of Fe₃O₄ in the acidic environment selectively convert H₂O₂ into highly toxic ^•OH by Fenton reaction, dramatically improving CDT with minimal systemic toxicity due to low NQO1 expression in normal tissues. Meanwhile, released Lapa consumes GSH in the tumor, amplifying oxidative stress and enhancing the efficacy of CDT. Designed Fe₃O₄-HSA@Lapa nanoparticles (NPs) exhibit perfect targeting capability, prolonged blood circulation, and increased tumor accumulation. Furthermore, Fe₃O₄-HSA@Lapa NPs effectively enhance the inhibition of tumor growth and reduce the side effects of anticancer drugs. This work establishes a remarkably enhanced tumor-selective CDT against NQO1-overexpressing tumors by significantly inducing intratumoral oxidative stress with minimal side effects.

Knockout of longevity gene Sirt1 in zebrafish leads to oxidative injury, chronic inflammation, and reduced life span

Sirt1, a member of the sirtuin gene family, encodes the most conserved mammalian NAD⁺-dependent deacetylase enzyme responsible for removing acetyl groups from many proteins. The Sirt1 gene is known as a longevity gene whose knockout in mice leads to decreased lifespan relative to the wild type. This study aimed to explore phenotypic changes in zebrafish Sirt1-knockouts and to investigate the function of the Sirt1 gene. Targeted knockout of Sirt1 in zebrafish (Danio rerio) was achieved using the CRISPR-Cas9 genome editing system. We created a 4-bp insertion-homozygote Sirt1-knockout zebrafish. Although there was no evident difference in appearance in the early stages of development, a significant increase in reactive oxygen species and in the extent of apoptosis in Sirt1-knockout zebrafish was observed. Sirt1 knockout caused inflammatory genes, including IL-1b, IL-6 and TNF-α to be highly expressed. Additionally, the lack of Sirt1 caused chronic inflammation and intestinal atrophy, thereby increasing pro-apoptotic events, which ultimately reduced the lifespan of transgenic zebrafish. Overall, our data demonstrate that lack of Sirt1 caused a significantly increased generation of reactive oxygen species that resulted in chronic inflammation and regeneration. Continuous repetition of these events played an important role in accelerating aging, thereby decreasing lifespan. Our findings using the knockout zebrafish model confirmed the association of the Sirt1 gene to aging processes and lifespan. Furthermore, the Sirt1-knockout mutant zebrafish developed in our study will surely be a valuable model to explore the mechanism of chronic inflammation.

Hypertrophic Cardiomyopathy: A Vicious Cycle Triggered by Sarcomere Mutations and Secondary Disease Hits

Significance: Hypertrophic cardiomyopathy (HCM) is a cardiac genetic disease characterized by left ventricular hypertrophy, diastolic dysfunction, and myocardial disarray. Disease onset occurs between 20 and 50 years of age, thus affecting patients in the prime of their life. HCM is caused by mutations in sarcomere proteins, the contractile building blocks of the heart. Despite increased knowledge of causal mutations, the exact path from genetic defect leading to cardiomyopathy is complex and involves additional disease hits. Recent Advances: Laboratory-based studies indicate that HCM development not only depends on the primary sarcomere impairment caused by the mutation but also on secondary disease-related alterations in the heart. Here we propose a vicious mutation-induced disease cycle, in which a mutation-induced energy depletion alters cellular metabolism with increased mitochondrial work, which triggers secondary disease modifiers that will worsen disease and ultimately lead to end-stage HCM. Critical Issues: Evidence shows excessive cellular reactive oxygen species (ROS) in HCM patients and HCM animal models. Oxidative stress markers are increased in the heart (oxidized proteins, DNA, and lipids) and serum of HCM patients. In addition, increased mitochondrial ROS production and changes in endogenous antioxidants are reported in HCM. Mutant sarcomeric protein may drive excessive levels of cardiac ROS via changes in cardiac efficiency and metabolism, mitochondrial activation and/or dysfunction, impaired protein quality control, and microvascular dysfunction. Future Directions: Interventions restoring metabolism, mitochondrial function, and improved ROS balance may be promising therapeutic approaches. We discuss the effects of current HCM pharmacological therapies and potential future therapies to prevent and reverse HCM. Antioxid. Redox Signal. 31, 318-358.

Cytotoxic unsaturated electrophilic compounds commonly target the ubiquitin proteasome system

A large number of natural products have been advocated as anticancer agents. Many of these compounds contain functional groups characterized by chemical reactivity. It is not clear whether distinct mechanisms of action can be attributed to such compounds. We used a chemical library screening approach to demonstrate that a substantial fraction (~20%) of cytotoxic synthetic compounds containing Michael acceptor groups inhibit proteasome substrate processing and induce a cellular response characteristic of proteasome inhibition. Biochemical and structural analyses showed binding to and inhibition of proteasome-associated cysteine deubiquitinases, in particular ubiquitin specific peptidase 14 (USP14). The results suggested that compounds bind to a crevice close to the USP14 active site with modest affinity, followed by covalent binding. A subset of compounds was identified where cell death induction was closely associated with proteasome inhibition and that showed significant antineoplastic activity in a zebrafish embryo model. These findings suggest that proteasome inhibition is a relatively common mode of action by cytotoxic compounds containing Michael acceptor groups and help to explain previous reports on the antineoplastic effects of natural products containing such functional groups.

Calotropis gigantea extract induces apoptosis through extrinsic/intrinsic pathways and reactive oxygen species generation in A549 and NCI-H1299 non-small cell lung cancer cells

Background

Calotropis gigantea (CG) is a tall and waxy flower that is used as a traditional remedy for fever, indigestion, rheumatism, leprosy, and leukoderma. However, the precise mechanisms of its anticancer effects have not yet been examined in human non-small cell lung cancer (NSCLC) cells. In this study, we investigated whether CG extract exerted an apoptotic effect in A549 and NCI-H1299 NSCLC cells.

Methods

The ethanol extract of CG was prepared, and its apoptotic effects on A549 and NCI-H1299 NSCLC cells were assessed by using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxy methoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay, annexin V-fluorescein isothiocyanate/propidium iodide (PI) staining, cell cycle analysis, real-time polymerase chain reaction (RT-PCR), western blotting, JC-1 staining, and ROS detection assay.

Results

The CG extract induced apoptosis through the stimulation of intrinsic and extrinsic signaling pathways in A549 and NCI-H1299 lung cancer cells. Cell cycle arrest was induced by the CG extract in both cell lines. Reactive oxygen species (ROS), which can induce cell death, were also generated in the CG-treated A549 and NCI-H1299 cells.

Conclusions

These data confirmed that CG caused apoptosis through the activation of extrinsic and intrinsic pathways, cell cycle arrest, and ROS generation in A549 and NCI-H1299 lung cancer cells. Thus, CG can be suggested as a potential agent for lung cancer therapy.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2561-1) contains supplementary material, which is available to authorized users.

DUSP26 regulates podocyte oxidative stress and fibrosis in a mouse model with diabetic nephropathy through the mediation of ROS

Diabetic nephropathy (DN) is a leading cause of renal failure worldwide. Unfortunately, the pathogenetic mechanism of DN is far from to be understood. Dual-specificity phosphatase 26 (DUSP26) is a member of the Dusp protein family, and is suggested to be involved in divers biological and pathological processes, such as cell growth, differentiation, inflammation and apoptosis. However, its role in the development of DN is still vague. In this study, we found that DUSP26 expression was increased in kidney of DN patients. Then, the wild type (DUSP26^+/+) and gene knockout (DUSP26^-/-) mice were used to further explore the effects of DUSP26 on DN development induced by streptozotocin (STZ). DUSP26 deficiency accelerated renal injury and dysfunction, as evidenced by the elevated glomerulosclerosis, reduced expression of Nephrin and promoted glomerular basement membrane thickness. In addition, STZ treatment resulted in reactive oxygen species (ROS) accumulation, H₂O₂ overproduction and superoxide dismutase (SOD) reduction in renal cortex or glomeruli of mice. The ROS production caused the activation of mitogen-activated protein kinase (MAPKs) signaling in kidney glomeruli of STZ-induced mice. These in vivo pathological processes were further confirmed in the differentiated podocytes stimulated by glucose (GLU). Intriguingly, we found that STZ-induced DN as mentioned above was further accelerated by DUSP26^-/- in mice following STZ injection. Moreover, STZ-induced fibrosis in kidney glomeruli of DN mice was markedly prolonged in DUSP26-knockout mice through potentiating transforming growth factor-β1 (TGF-β1) expression. More importantly, reducing ROS generation could significantly abolish DUSP26 knockdown-exacerbated TGF-β1 expression and MAPKs activation, thereby protecting podocytes from GLU-induced podocyte injury. Thus, DUSP26-regulated DN development was largely dependent on ROS generation. Taken together, we concluded that DUSP26 might be a promising therapeutic target for developing effective treatments against DN progression.

Cytosolic translational responses differ under conditions of severe short-term and long-term mitochondrial stress

Previous studies demonstrated that cells inhibit protein synthesis as a compensatory mechanism for mitochondrial dysfunction. Protein synthesis can be attenuated by 1) the inhibition of mTOR kinase, which results in a decrease in the phosphorylation of S6K1 and 4E-BP1 proteins, and 2) an increase in the phosphorylation of eIF2α protein. The present study investigated both of these pathways under conditions of short-term acute and long-term mitochondrial stress. Short-term responses were triggered in mammalian cells by treatment with menadione, antimycin A, or CCCP. Long-term mitochondrial stress was induced by prolonged treatment with menadione or rotenone and expression of genetic alterations, such as knocking down the MIA40 oxidoreductase or knocking out NDUFA11 protein. Short-term menadione, antimycin A, or CCCP cell treatment led to the inhibition of protein synthesis, accompanied by a decrease in mTOR kinase activity, an increase in the phosphorylation of eIF2α (Ser51), and an increase in the level of ATF4 transcription factor. Conversely, long-term stress led to a decrease in eIF2α (Ser51) phosphorylation and ATF4 expression and to an increase in S6K1 (Thr389) phosphorylation. Thus, under long-term mitochondrial stress, cells trigger long-lasting adaptive responses for protection against excessive inhibition of protein synthesis.

Water-soluble pristine C60 fullerene attenuates acetaminophen-induced liver injury

Introduction: Oxidative stress has been suggested as the main trigger and pathological mechanism of toxic liver injury. Effects of powerful free radical scavenger С₆₀ fullerene on rat liver injury and liver cells (HepG2 line) were aimed to be discovered.

Methods: Acute liver injury (ALI) was simulated by single acetaminophen (APAP, 1000 mg/kg) administration, on a chronic CLI, by 4 weekly APAP administrations. Pristine C₆₀ fullerene aqueous colloid solution (C₆₀FAS; initial concentration 0.15 mg/mL) was administered per os or intraperitoneally at a dose of 0.5 mg/kg (ALI) or 0.25 mg/kg (CLI) daily for 2 or 28 days, respectively, after first APAP dose. Animals were sacrificed at 24th hour after the last dose. Biochemical markers of blood serum and liver autopsies were analyzed. EGFR expression in HepG2 cells after 48-hour incubation with C₆₀FAS was assessed.

Results: Increase of serum conjugated and unconjugated bilirubin (up to 1.4-3.7 times), ALT (by 31-37%), and AST (by 18%) in non-treated ALI and CLI rats were observed, suggesting the hepatitis (confirmed by histological analysis). Liver morphological state (ALI, CLI), ALT (ALI and CLI), bilirubin (CLI), α-amylase, and creatinine (ALI) were normalized with C₆₀FAS administration in both ways, which may indicate its protective impact on liver. However, unconjugated bilirubin sharply increased in ALI animals receiving C₆₀FAS (up to 12 times compared to control), suggesting the augmentation of bilirubin metabolism. Furthermore, C₆₀FAS inhibited EGFR expression in HepG2 cells in a dose-dependent manner.

Conclusion: C₆₀FAS could partially correct acute and chronic toxic liver injury, however, it could not normalize bilirubin metabolism after acute exposure.

7-Ketocholesterol Promotes Oxiapoptophagy in Bone Marrow Mesenchymal Stem Cell from Patients with Acute Myeloid Leukemia

7-Ketocholesterol (7-KC) is a cholesterol oxidation product with several biological functions. 7-KC has the capacity to cause cell death depending on the concentration and specific cell type. Mesenchymal stem cells (MSCs) are multipotent cells with the ability to differentiate into various types of cells, such as osteoblasts and adipocytes, among others. MSCs contribute to the development of a suitable niche for hematopoietic stem cells, and are involved in the development of diseases, such as leukemia, to a yet unknown extent. Here, we describe the effect of 7-KC on the death of bone marrow MSCs from patients with acute myeloid leukemia (LMSCs). LMSCs were less susceptible to the death-promoting effect of 7-KC than other cell types. 7-KC exposure triggered the extrinsic pathway of apoptosis with an increase in activated caspase-8 and caspase-3 activity. Mechanisms other than caspase-dependent pathways were involved. 7-KC increased ROS generation by LMSCs, which was related to decreased cell viability. 7-KC also led to disruption of the cytoskeleton of LMSCs, increased the number of cells in S phase, and decreased the number of cells in the G1/S transition. Autophagosome accumulation was also observed. 7-KC downregulated the SHh protein in LMSCs but did not change the expression of SMO. In conclusion, oxiapoptophagy (OXIdative stress + APOPTOsis + autophagy) seems to be activated by 7-KC in LMSCs. More studies are needed to better understand the role of 7-KC in the death of LMSCs and the possible effects on the SHh pathway.

Initial biological evaluations of 18F-KS1, a novel ascorbate derivative to image oxidative stress in cancer

BACKGROUND

Reactive oxygen species (ROS)-induced oxidative stress damages many cellular components such as fatty acids, DNA, and proteins. This damage is implicated in many disease pathologies including cancer and neurodegenerative and cardiovascular diseases. Antioxidants like ascorbate (vitamin C, ascorbic acid) have been shown to protect against the deleterious effects of oxidative stress in patients with cancer. In contrast, other data indicate potential tumor-promoting activity of antioxidants, demonstrating a potential temporal benefit of ROS. However, quantifying real-time tumor ROS is currently not feasible, since there is no way to directly probe global tumor ROS. In order to study this ROS-induced damage and design novel therapeutics to prevent its sequelae, the quantitative nature of positron emission tomography (PET) can be harnessed to measure in vivo concentrations of ROS. Therefore, our goal is to develop a novel translational ascorbate-based probe to image ROS in cancer in vivo using noninvasive PET imaging of tumor tissue. The real-time evaluations of ROS state can prove critical in developing new therapies and stratifying patients to therapies that are affected by tumor ROS.

METHODS

We designed, synthesized, and characterized a novel ascorbate derivative (E)-5-(2-chloroethylidene)-3-((4-(2-fluoroethoxy)benzyl)oxy)-4-hydroxyfuran-2(5H)-one (KS1). We used KS1 in an in vitro ROS MitoSOX-based assay in two different head and neck squamous cancer cells (HNSCC) that express different ROS levels, with ascorbate as reference standard. We radiolabeled 18F-KS1 following 18F-based nucleophilic substitution reactions and determined in vitro reactivity and specificity of 18F-KS1 in HNSCC and prostate cancer (PCa) cells. MicroPET imaging and standard biodistribution studies of 18F-KS1 were performed in mice bearing PCa cells. To further demonstrate specificity, we performed microPET blocking experiments using nonradioactive KS1 as a blocker.

RESULTS

KS1 was synthesized and characterized using 1H NMR spectra. MitoSOX assay demonstrated good correlations between increasing concentrations of KS1 and ascorbate and increased reactivity in SCC-61 cells (with high ROS levels) versus rSCC-61cells (with low ROS levels). 18F-KS1 was radiolabeled with high radiochemical purity (> 94%) and specific activity (~ 100 GBq/μmol) at end of synthesis (EOS). Cell uptake of 18F-KS1 was high in both types of cancer cells, and the uptake was significantly blocked by nonradioactive KS1, and the ROS blocker, superoxide dismutase (SOD) demonstrating specificity. Furthermore, 18F-KS1 uptake was increased in PCa cells under hypoxic conditions, which have been shown to generate high ROS. Initial in vivo tumor uptake studies in PCa tumor-bearing mice demonstrated that 18F-KS1 specifically bound to tumor, which was significantly blocked (threefold) by pre-injecting unlabeled KS1. Furthermore, biodistribution studies in the same tumor-bearing mice showed high tumor to muscle (target to nontarget) ratios.

CONCLUSION

This work demonstrates the strong preliminary support of 18F-KS1, both in vitro and in vivo for imaging ROS in cancer. If successful, this work will provide a new paradigm to directly probe real-time oxidative stress levels in vivo. Our work could enhance precision medicine approaches to treat cancer, as well as neurodegenerative and cardiovascular diseases affected by ROS.

Critical role of H2O2 in mediating sanguinarine-induced apoptosis in prostate cancer cells via facilitating ceramide generation, ERK1/2 phosphorylation, and Par-4 cleavage

Natural products are a major source of potential anticancer agents, and in order to develop improved and more effective cancer treatments, there is an immense need in exploring and elucidating their mechanism of action. Sanguinarine (SNG), a quaternary benzophenanthridine alkaloid, has been shown to induce cytotoxicity in various human cancers and suppresses various pro-tumorigenic processes such as invasion, angiogenesis, and metastasis in different cancers. Lack of understanding the anticancer mechanism(s) of SNG has impeded the development of this molecule as a potential anticancer agent. Earlier, we have reported that SNG induces reactive oxygen species (ROS)-dependent ceramide (Cer) generation and Akt dephosphorylation, leading to the induction of apoptosis in human leukemic cells. In the present study, we demonstrate that SNG has potent anti-proliferative activity against prostate cancer cells. Our data suggest that SNG induces Cer generation via inhibiting acid ceramidase and glucosylceramide synthase, two important enzymes involved in Cer metabolism. Furthermore, we demonstrate that SNG induces ROS-depended extracellular signal-regulated kinase1/2 (ERK1/2) phosphorylation, and prostate apoptosis response-4 (Par-4) cleavage, leading to the induction of apoptosis in human prostate cancer cells. Overall, our findings provide molecular insight into the role of ROS signaling in the anticancer mechanism(s) of SNG. This may provide the basis for its use as a nontoxic and an effective therapeutic agent in the treatment of prostate cancer.

Greensporone A, a Fungal Secondary Metabolite Suppressed Constitutively Activated AKT via ROS Generation and Induced Apoptosis in Leukemic Cell Lines

Greensporone A is a fungal secondary metabolite that has exhibited potential in vitro for anti-proliferative activity in vitro. We studied the anticancer activity of greensporone A in a panel of leukemic cell lines. Greensporone A-mediated inhibition of proliferation is found to be associated with the induction of apoptotic cell death. Greensporone A treatment of leukemic cells causes inactivation of constitutively activated AKT and its downstream targets, including members GSK3 and FOXO1, and causes downregulation of antiapoptotic genes such as Inhibitor of Apoptosis (IAPs) and Bcl-2. Furthermore, Bax, a proapoptotic member of the Bcl-2 family, was found to be upregulated in leukemic cell lines treated with greensporone A. Interestingly, gene silencing of AKT using AKT specific siRNA suppressed the expression of Bcl-2 with enhanced expression of Bax. Greensporone A-mediated increase in Bax/Bcl-2 ratio causes permeabilization of the mitochondrial membrane leading to the accumulation of cytochrome c in the cytoplasm. Greensporone A-induced cytochrome c accumulation causes the activation of caspase cascade and cleavage of its effector, poly(ADP-ribose) polymerase (PARP), leading to apoptosis. Greensporone A-mediated apoptosis in leukemic cells occurs through the generation of reactive oxygen species (ROS) due to depletion of glutathione (GSH) levels. Finally, greensporone A potentiated the anticancer activity of imatinib in leukemic cells. In summary, our study showed that greensporone A suppressed the growth of leukemic cells via induction of apoptotic cell death. The apoptotic cell death occurs by inhibition of AKT signaling and activation of the intrinsic apoptotic/caspase pathways. These results raise the possibility that greensporone A could be developed as a therapeutic agent for the treatment of leukemia and other hematological malignancies.

Preliminary Study of Ge-DLC Nanocomposite Biomaterials Prepared by Laser Codeposition

This paper deals with the synthesis and study of the properties of germanium-doped diamond-like carbon (DLC) films. For deposition of doped DLC films, hybrid laser technology was used. Using two deposition lasers, it was possible to arrange the dopant concentrations by varying the laser repetition rate. Doped films of Ge concentrations from 0 at.% to 12 at.% were prepared on Si (100) and fused silica (FS) substrates at room temperature. Film properties, such as growth rate, roughness, scanning electron microscopy (SEM) morphology, wavelength dependent X-ray spectroscopy (WDS) composition, VIS-near infrared (IR) transmittance, and biological properties (cytotoxicity, effects on cellular morphology, and ability to produce reactive oxygen species (ROS)) were studied in relation to codeposition conditions and dopant concentrations. The analysis showed that Ge-DLC films exhibit cytotoxicity for higher Ge doping.

Carbon nanotubes and crystalline silica stimulate robust ROS production, inflammasome activation, and IL-1β secretion in macrophages to induce myofibroblast transformation

Pulmonary exposure to inhaled particulates elicits complex inflammatory and fibrotic responses that may progress to chronic fibrosis. The fibrogenic potentials of respirable particulates are influenced by their physicochemical properties and their interactions with major pathways to drive fibrotic development in the lung. Macrophages were exposed to six carbon nanotubes (CNTs) of varying dimensions, crystalline silica, or carbon black (CB), with lipopolysaccharide (LPS) and transforming growth factor (TGF)-β1 as positive controls. Macrophage-conditioned media was collected and applied to cultures of human pulmonary fibroblast line WI38-VA13 to induce myofibroblast transformation. Multi-walled and single-walled CNTs (MWCNTs and SWCNTs, respectively) and silica, but not CB, stimulated robust myofibroblast transformation through macrophage-conditioned media. On an equal weight basis, MWCNTs induced higher induction than SWCNTs. High induction was observed for MWCNTs with a long and slender or a short and rigid shape, and silica, at levels comparable to those by LPS and TGF-β1. Fibrogenic particulates induced high levels of IL-1β mRNA expression and protein secretion that are required for macrophage-guided myofibroblast transformation. Induction of IL-1β is dependent on the activation of the NLRP3 (NOD-like receptor family, pyrin domain containing 3) inflammasome and ROS (reactive oxygen species) production in macrophages, as inhibition of NLRP3 by MCC950 and reduction of ROS production by N-acetylcysteine blocked NLRP3 activation, IL-1β induction, and fibroblast activation and differentiation. Therefore, fibrogenic CNTs and silica, but not CB, elicit robust macrophage-guided myofibroblast transformation, which depends on the induction of IL-1β through the NLRP3 inflammasome pathway and the increased production of ROS in macrophages.

Sustained release of N-acetylcysteine by sandwich structured polycaprolactone/collagen scaffolds for wound healing

PCL (poly-caprolactone) nanofibers have good biocompatibility and high porosity, which are usually utilized for application in wound dressings. However, wound healing could be hindered by the overproduction of reactive oxygen species (ROS) and different factors. Pure nanofibers cannot satisfy these requirements of wound healing. N-acetylcysteine (NAC), as an antioxidant, meets the requirements for wound healing by resisting the overproduction of ROS and by promoting angiogenesis and maturation of the epidermis. In this study, we prepared a sandwich structured PCL-Col/NAC scaffold using the molding method, which consisted of PCL nanofibers at the core and NAC-loaded collagen on both sides. The hydroscopicity and tensile modulus of PCL-Col/NAC scaffolds showed best performance of these properties among groups. Meanwhile, the drug release profiles of PCL-Col/NAC scaffolds were investigated using the HPLC method and the results suggested a sustained drug release of NAC for PCL-Col/NAC scaffolds. In addition, PCL-Col/NAC scaffolds presented better properties than the control groups in cell migration and proliferation. The in vivo wound healing therapy effect was studied using an oval (2 × 1 cm) full-thickness skin defect wound model for SD rats. After 21 days, gross view and histological analysis showed a favorable beneficial therapeutic effect as well as better epidermal maturation compared with the control groups. CD31 immunohistology results revealed relatively more new vessels in the PCL-Col/NAC group than the control groups. This study developed novel PCL-Col/NAC scaffolds with an excellent hydroscopicity, tensile modulus and the ability to promote epidermal maturation and angiogenesis, demonstrating its promising potential in wound healing treatment. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2019.

TRIM69 inhibits cataractogenesis by negatively regulating p53

Ultraviolet B (UVB) irradiation can induce reactive oxygen species (ROS) production and apoptosis in human lens epithelial cells (HLECs), thus leading to the formation of cataracts. We studied the role of tripartite motif 69 (TRIM69) in cataract formation. The expression of TRIM69 protein was down-regulated in both human cataract capsule tissues and HLECs treated with UVB, whereas the expression of p53 protein exhibited an opposite trend. Ectopic expression of TRIM69 in HLECs significantly suppressed UVB-induced apoptosis and ROS production, whereas knockdown of TRIM69 promoted apoptosis and ROS production. TRIM69 can interact with p53 and induce its ubiquitination. The effects of TRIM69 overexpression in UVB-induced cell apoptosis and ROS production was clearly weakened by p53 overexpression, thus suggesting a role for p53 in TRIM69 functions. Furthermore, inhibition of ROS mitigated the effects of UVB irradiation on ROS production, cell apoptosis, forkhead box protein 3a (Foxo3a) phosphorylation, and TRIM69 expression. Additionally, Foxo3a overexpression significantly enhanced TRIM69 promoter activity, whereas Foxo3a knockdown had the opposite effect. In conclusion, we provide the first demonstration that Foxo3a is a potential transcription factor for TRIM69, and TRIM69 induces p53 ubiquitination. These results suggest that the Foxo3a/TRIM69/p53 regulatory network may be involved in cataract formation.

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TRIM69 significantly suppressed UVB-induced apoptosis and ROS production.

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TRIM69 can interact with p53 and induce its ubiquitination.

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Foxo3a overexpression significantly enhanced TRIM69 promoter activity.

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The Foxo3a/TRIM69/p53 regulatory network may be involved in cataract formation.

Saturated Fatty Acid Activates T Cell Inflammation Through a Nicotinamide Nucleotide Transhydrogenase (NNT)-Dependent Mechanism

Circulating fatty acids (FAs) increase with obesity and can drive mitochondrial damage and inflammation. Nicotinamide nucleotide transhydrogenase (NNT) is a mitochondrial protein that positively regulates nicotinamide adenine dinucleotide phosphate (NADPH), a key mediator of energy transduction and redox homeostasis. The role that NNT-regulated bioenergetics play in the inflammatory response of immune cells in obesity is untested. Our objective was to determine how free fatty acids (FFAs) regulate inflammation through impacts on mitochondria and redox homeostasis of peripheral blood mononuclear cells (PBMCs). PBMCs from lean subjects were activated with a T cell-specific stimulus in the presence or absence of generally pro-inflammatory palmitate and/or non-inflammatory oleate. Palmitate decreased immune cell expression of NNT, NADPH, and anti-oxidant glutathione, but increased reactive oxygen and proinflammatory Th17 cytokines. Oleate had no effect on these outcomes. Genetic inhibition of NNT recapitulated the effects of palmitate. PBMCs from obese (BMI >30) compared to lean subjects had lower NNT and glutathione expression, and higher Th17 cytokine expression, none of which were changed by exogenous palmitate. Our data identify NNT as a palmitate-regulated rheostat of redox balance that regulates immune cell function in obesity and suggest that dietary or therapeutic strategies aimed at increasing NNT expression may restore redox balance to ameliorate obesity-associated inflammation.

Synthesis of Non-Symmetrical Nitrogen-Containing Curcuminoids in the Pursuit of New Anticancer Candidates

Curcumin is known to display pronounced anticancer effects and a variety of other biological activities. However, the low bioavailability and fast metabolism of this molecule present an issue of concern with respect to its medicinal applications. To address this issue, structural modifications of the curcumin scaffold can be envisioned as a strategy to improve both the solubility and stability of this chemical entity, without compromising its biological activities. Previous work in our group targeted the synthesis of symmetrical azaheteroaromatic curcuminoids, which showed better solubility and cytotoxicity profiles compared to curcumin. In continuation of that work, we now focused on the synthesis of non-symmetrical nitrogen-containing curcuminoids bearing both a phenolic and an azaheteroaromatic moiety. In that way, we aimed to combine good solubility, antioxidant potential and cytotoxic properties into one molecule. Some derivatives were selected for further chemical modification of their rather labile β-diketone scaffold to the corresponding pyrazole moiety. In this way, thirteen new non-symmetrical aza-aromatic curcuminoids and four pyrazole-based analogues were successfully synthesized in a yield of 11-69 %. All newly synthesized analogues were evaluated for their antioxidant properties, reactive oxygen species (ROS) production, water solubility and anticancer activities. Several novel derivatives displayed good cytotoxicity profiles compared to curcumin, in combination with an improved water solubility and stability, and were thus identified as potential hit scaffolds for further optimization studies.

Phellodendrine chloride suppresses proliferation of KRAS mutated pancreatic cancer cells through inhibition of nutrients uptake via macropinocytosis

Despite the massive efforts to develop the treatment of pancreatic cancers, no effective application exhibits satisfactory clinical outcome. Macropinocytosis plays a critical role for continuous proliferation of pancreatic ductal adenocarcinoma (PDAC). In this study, we generated a screening method and identified phellodendrine chloride (PC) as a potential macropinocytosis inhibitor. PC significantly inhibited the viability of KRAS mutant pancreatic cancer cells (PANC-1 and MiaPaCa-2) in a dose-dependent manner; however, it did not affect the wild type KRAS pancreatic cancer cells (BxPC-3). Further experiments indicated that PC reduced the growth of PANC-1 cells through inhibition of macropinocytosis and diminishing the intracellular glutamine level. Disruption of glutamine metabolism led to enhance the reactive oxygen species level and induce mitochondrial membrane potential depolarization in PANC-1 cells. PC treatment caused increased Bax and decreased Bcl-2 expression, along with the activation of cleaved caspase-3, 7, 9 and cleaved-PARP, thus induced mitochondrial apoptosis. Moreover, PC inhibited macropinocytosis in vivo and effectively reduced the growth of PANC-1 xenograft tumors. All together, we demonstrated that inhibition of macropinocytosis might be an effective strategy to treat pancreatic cancers. Thus, PC could be a potential compound with improved therapeutic efficacy in patients with pancreatic cancers.

When the strategies for cellular selectivity fail. Challenges and surprises in the design and application of fluorescent benzothiadiazole derivatives for mitochondrial staining

Design, synthesis, molecular architecture and the unexpected behavior of fluorescent benzothiadiazole for selective mitochondrial and plasma membrane staining are investigated.

MS-5, a Naphthalene Derivative, Induces the Apoptosis of an Ovarian Cancer Cell CAOV-3 by Interfering with the Reactive Oxygen Species Generation

Reactive oxygen species (ROS) are widely generated in biological processes such as normal metabolism and response to xenobiotic exposure. While ROS can be beneficial or harmful to cells and tissues, generation of ROS by diverse anti-cancer drugs or phytochemicals plays an important role in the induction of apoptosis. We recently identified a derivative of naphthalene, MS-5, that induces apoptosis of an ovarian cell, CAOV-3. Interestingly, MS-5 induced apoptosis by down-regulating the ROS. Cell viability was evaluated by water-soluble tetrazolium salt (WST-1) assay. Apoptosis was evaluated by flow cytometry analysis. Intracellular ROS (H₂O₂), mitochondrial superoxide, mitochondrial membrane potential (MMP) and effect on cycle were determined by flow cytometry. Protein expression was assessed by western blotting. The level of ATP was measured using ATP Colorimetric/Fluorometric Assay kit. MS-5 inhibited growth of ovarian cancer cell lines, CAOV-3, in a concentration- and time-dependent manner. MS-5 also induced G1 cell cycle arrest in CAOV-3 cells, while MS-5 decreased intracellular ROS generation. In addition, cells treated with MS-5 showed the decrease in MMP and ATP production. In this study, we found that treatment with MS-5 in CAOV-3 cells induced apoptosis but decreased ROS level. We suspect that MS-5 might interfere with the minimum requirements of ROS for survival. These perturbations appear to be concentration-dependent, suggesting that MS-5 may induce apoptosis by interfering with ROS generation. We propose that MS-5 may be a potent therapeutic agent for inducing apoptosis in ovarian cancer cell through regulation of ROS.

Tannic acid-stabilized gold nano-particles are superior to native tannic acid in inducing ROS-dependent mitochondrial apoptosis in colorectal carcinoma cells via the p53/AKT axis

Tannic acid and AuNP-TA lead to death of colon cancer cells via the ROS/p53/Akt pathway, and AuNP-TA is more potent.

Roles of intracellular and extracellular ROS formation in apoptosis induced by cold atmospheric helium plasma and X-irradiation in the presence of sulfasalazine

Sulfasalazine (SSZ) is a well-known anti-inflammatory drug and also an inhibitor of the cystine-glutamate antiporter that is known to reduce intracellular glutathione (GSH) level and increase cellular oxidative stress, indicating its anti-tumor potential. However, the combination of SSZ with other physical modalities remains unexplored. Here, the effects of SSZ on cold atmospheric helium plasma (He-CAP), which produces approximately 24 x higher concentration of hydroxyl radicals (. OH) compared to X-irradiation (IR) in aqueous solution, and on IR-induced apoptosis in human leukemia Molt-4 cells were studied to elucidate the mechanism of apoptosis enhancement. Both the Annexin V-FITC/PI and DNA fragmentation assay revealed that pre-treatment of cells with SSZ significantly enhanced He-CAP and IR-induced apoptosis. Similar enhancement was observed during the loss of mitochondrial membrane potential, intracellular Ca²⁺ ions, and mitochondria- and endoplasmic reticulum-related proteins. The concentration of intracellular reactive oxygen species (ROS) was much higher in He-CAP treated cells than in X-irradiated cells. On the other hand, strong enhancement of Fas expression and caspase-8 and -3 activities were only observed in X-irradiated cells. It might be possible that the higher concentration of intracellular and extracellular ROS suppressed caspase activities and Fas expression in He-CAP-treated cells. Notably, pretreating the cells with an antioxidant N-acetyl-L-cysteine (NAC) dramatically decreased apoptosis in cells treated by He-CAP, but not by IR. These results suggest that IR-induced apoptosis is due to specific and effective ROS distribution since intracellular ROS formation is marginal and the high production of ROS inside and outside of cells plays unique roles in He-CAP induced apoptosis. We conclude that our data provides efficacy and mechanistic insights for SSZ, which might be helpful for establishing SSZ as a future sensitizer in He-CAP or IR therapy for cancer.

Regulatory Activities of Dopamine and Its Derivatives toward Metal-Free and Metal-Induced Amyloid-β Aggregation, Oxidative Stress, and Inflammation in Alzheimer's Disease

A catecholamine neurotransmitter, dopamine (DA), is suggested to be linked to the pathology of dementia; however, the involvement of DA and its structural analogues in the pathogenesis of Alzheimer's disease (AD), the most common form of dementia, composed of multiple pathogenic factors has not been clear. Herein, we report that DA and its rationally designed structural derivatives (1-6) based on DA's oxidative transformation are able to modulate multiple pathological elements found in AD [i.e., metal ions, metal-free amyloid-β (Aβ), metal-bound Aβ (metal-Aβ), and reactive oxygen species (ROS)], with demonstration of detailed molecular-level mechanisms. Our multidisciplinary studies validate that the protective effects of DA and its derivatives on Aβ aggregation and Aβ-mediated toxicity are induced by their oxidative transformation with concomitant ROS generation under aerobic conditions. In particular, DA and the derivatives (i.e., 3 and 4) show their noticeable anti-amyloidogenic ability toward metal-free Aβ and/or metal-Aβ, verified to occur via their oxidative transformation that facilitates Aβ oxidation. Moreover, in primary pan-microglial marker (CD11b)-positive cells, the major producers of inflammatory mediators in the brain, DA and its derivatives significantly diminish inflammation and oxidative stress triggered by lipopolysaccharides and Aβ through the reduced induction of inflammatory mediators as well as upregulated expression of heme oxygenase-1, the enzyme responsible for production of antioxidants. Collectively, we illuminate how DA and its derivatives could prevent multiple pathological features found in AD. The overall studies could advance our understanding regarding distinct roles of neurotransmitters in AD and identify key interactions for alleviation of AD pathology.

Green Platinum Nanoparticles Interaction With HEK293 Cells: Cellular Toxicity, Apoptosis, and Genetic Damage

Metal nanoparticles are widely used in industry, agriculture, textiles, drugs, and so on. The adverse effect of green platinum nanoparticles on human embryonic kidney (HEK293) cells is not well established. In the current study, green platinum nanoparticles were synthesized using leaf extract of Azadirachta indica L. Green platinum nanoparticles were characterized by dynamic light scattering and transmission electron microscope. The cytotoxicity of green platinum nanoparticle was observed in HEK293 cells by applying 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) and Neutral red uptake (NRU) assays. Cell viability of the cells was decreased in a concentration and duration-dependent manner. Generation of reactive oxygen species (ROS) in HEK293 cells due to green platinum nanoparticles was examined using fluorescent dye 2,7-dichlorofluorescein diacetate (DCFDA), and ROS was increased according to exposure pattern. The cytotoxicity of HEK293 cells was correlated with increased caspase 3, depolarization of mitochondrial membrane potential, and DNA fragmentation. The abovementioned finding confirmed that mitochondria play an important role in genotoxicity and cytotoxicity induced by nanoparticles in HEK293 cells. Further, we determined other oxidative stress biomarkers, lipid peroxide (LPO) and glutathione (GSH); LPO was increased and GSH was decreased in HEK293 cells. It is also important to indicate that HEK293 cells appear to be more susceptible to green platinum nanoparticles exposure after 24 hours. This result provides a dose- and time-dependent apoptosis and genotoxicity of green nanoparticles on HEK293 cells.

Protective Effect of N-Acetylcysteine against Oxidative Stress Induced by Zearalenone via Mitochondrial Apoptosis Pathway in SIEC02 Cells

Zearalenone (ZEN), a nonsteroidal estrogen mycotoxin, is widely found in feed and foodstuffs. Intestinal cells may become the primary target of toxin attack after ingesting food containing ZEN. Porcine small intestinal epithelial (SIEC02) cells were selected to assess the effect of ZEN exposure on the intestine. Cells were exposed to ZEN (20 µg/mL) or pretreated with (81, 162, and 324 µg/mL) N-acetylcysteine (NAC) prior to ZEN treatment. Results indicated that the activities of glutathione peroxidase (Gpx) and glutathione reductase (GR) were reduced by ZEN, which induced reactive oxygen species (ROS) and malondialdehyde (MDA) production. Moreover, these activities increased apoptosis and mitochondrial membrane potential (ΔΨm), and regulated the messenger RNA (mRNA) expression of Bax, Bcl-2, caspase-3, caspase-9, and cytochrome c (cyto c). Additionally, NAC pretreatment reduced the oxidative damage and inhibited the apoptosis induced by ZEN. It can be concluded that ZEN-induced oxidative stress and damage may further induce mitochondrial apoptosis, and pretreatment of NAC can degrade this damage to some extent.