Downregulation of Reactive Oxygen Species in Apoptosis

Iminoamido chelated iridium(III) and ruthenium(II) anticancer complexes with mitochondria-targeting ability and potential to overcome cisplatin resistance

A diverse set of neutral half-sandwich iminoamido iridium and ruthenium organometallic complexes is synthesized through the utilization of Schiff base pro-ligands with N˄N donors. Notably, these metal complexes with varying leaving groups (Cl- or OAc-) are formed by employing different quantities of the deprotonating agent NaOAc, and exhibit promising cytotoxicity against various cancer cell lines such as A549 and cisplatin-resistant A549/DDP lung cancer cells, as well as HeLa cells, with IC50 values spanning from 9.26 to 15.98 μM. Cytotoxicity and anticancer selectivity (SI: 1.9-2.4) of these metal complexes remain unaffected by variations in the metal center, leaving group, and ligand substitution. Further investigations reveal that these metal complexes specifically target mitochondria, leading to the depolarization of the mitochondrial membrane and instigating the production of intracellular reactive oxygen species. Furthermore, the metal complexes are found to induce late apoptosis and disrupt the cell cycle, leading to G2/M cell cycle arrest specifically in A549 cancer cells. In light of these findings, it is evident that the primary mechanism contributing to the anticancer effectiveness of these metal complexes is the redox pathway.

Molecular Mechanisms of Anticarcinogenic Potential of Hydrocotyle umbellata and Its Major Components

Despite the development of several anticancer treatments, there remains a need for new drugs that can overcome resistance and reduce side effects. While the medicinal herb Hydrocotyle umbellata (H. umbellata) has been used to relieve pain and inflammation, its antitumor properties have not yet been explored. In this study, we investigated the anticarcinogenic potential of H. umbellata extract (HUE) and its major components, as well as the underlying molecular mechanisms. Our results showed that HUE inhibited the growth of various tumor cell lines, including B16F10, without affecting non-cancer cells. Furthermore, HUE was effective in treating and preventing tumor growth in mice. Our mechanistic studies revealed that HUE inhibited cellular respiration, thereby reducing tumor cell proliferation. When combined with 2-deoxy-D-glucose, HUE demonstrated an enhanced anticancer effect by increasing the rate apoptosis. Analysis of the ethyl acetate and n-butanol fractions of HUE identified 1,3,4-trihydroxy-2-butanyl-α-d-glucopyranoside and caffeoylquinic acid derivatives as the major components responsible for the observed anticancer effects. In conclusion, our findings suggest that HUE and its two major components have the potential to be developed as effective therapeutic agents for a wide range of tumors by targeting cancer cell metabolism.

The mechanism of anticancer effects of some pyrrolopyrimidine derivatives on HT-29 human colon cancer cells

In the present work, the mechanism of anticancer activity of some pyrrolopyrimidine derivatives was evaluated. Compounds 5 and 8 exhibiting significant antiproliferative activity against HT-29 cells with IC50 values of 4.17 μM and 2.96, arrested the cells at the G2/M phase and significantly induced apoptosis. The apoptotic potential of the compounds has been verified via ELISA assay, which resulted in increased BAX, PUMA, BIM, and cleaved caspase 3 expression and decreased BCL-XL and MCL-1 protein levels in HT-29 cells. Moreover, the immunofluorescence technique showing that compounds 5 and 8-treatment reduced Ki67 immunolocalization and increased the caspase 3 and p53 immunolocalization confirmed the apoptotic activity. While treatment of HT-29 cells to compounds 5 and 8 inhibited Akt and ERK1/2, there are no alterations in JNK and p38 signaling pathways. According to molecular docking results, compounds 5 and 8 occupied the active site of Akt kinase and showed important hydrogen bonding interactions with key amino acids. Also, siRNA-mediated depletion of BIM, PUMA, and BAX/BAK expression decreased apoptotic response in HT-29 cells upon exposure to compound 5 and compound 8. Compounds 5 and 8 trigger the activation of mitochondrial apoptosis in HT-29 cells. Additionally, we found that proapoptotic BH3-only proteins BIM and PUMA are required for the full engagement of mitochondrial apoptosis signaling. However, p53 was dispensable for compound 5- or compound 8-induced apoptosis in HT-29 cells.

Astragalus polysaccharides ameliorate osteoarthritis via inhibiting apoptosis by regulating ROS-mediated ASK1/p38 MAPK signaling pathway targeting on TXN

This research aims to explore the potential of astragalus polysaccharides (APS) in treating osteoarthritis. The primary component of APS extracted in this study was glucose, and noticeably it had a relatively high content of glucuronic acids. In vitro, APS reduced ROS levels, protected chondrocytes from apoptosis, and promoted collagen II expression by regulating ASK1 (apoptosis-signal-regulating kinase1)/p38 cell apoptosis pathway. Further co-immunoprecipitation and immunofluorescence localization experiments demonstrated that the thioredoxin (TXN) antioxidant system was responsible for its bioactivity. Moreover, TXN silencing remarkably blocked the protective effects of APS, indicating that APS inhibited chondrocyte apoptosis by targeting TXN. In vivo, APS effectively mitigated cartilage loss and chondrocyte apoptosis and decreased expressions of p-ASK1 and p-p38. Collectively, this research first demonstrated that APS could ameliorate osteoarthritis by ASK1/p38 signaling pathway through regulating thioredoxin. In conclusion, APS holds promise as a nutraceutical supplement for osteoarthritis in future drug development.

Mitochondria-targeted neutral and cationic iridium(III) anticancer complexes chelating simple hybrid sp2-N/sp3-N donor ligands

Most platinum group-based cyclometalated neutral and cationic anticancer complexes with the general formula [(C^N)2Ir(XY)]0/+ (neutral complex: XY = bidentate anionic ligand; cationic complex: XY = bidentate neutral ligand) are notable owing to their intrinsic luminescence properties, good cell permeability, interaction with some biomolecular targets and unique mechanisms of action (MoAs). We herein synthesized a series of neutral and cationic amine-imine cyclometalated iridium(III) complexes using Schiff base ligands with sp2-N/sp3-N N^NH2 chelating donors. The cyclometalated iridium(III) complexes were identified by various techniques. They were stable in aqueous media, displayed moderate fluorescence and exhibited affinity toward bovine serum albumin (BSA). The complexes demonstrated promising cytotoxicity against lung cancer A549 cells, cisplatin-resistant lung cancer A549/DDP cells, cervical carcinoma HeLa cells and human liver carcinoma HepG2 cells, with IC50 values ranging from 9.98 to 19.63 μM. Unfortunately, these complexes had a low selectivity (selectivity index: 1.62-1.98) towards A549 cells and BEAS-2B normal cells. The charge pattern of the metal center (neutral or cationic) and ligand substituents showed little influence on the cytotoxicity and selectivity of these complexes. The study revealed that these complexes could target mitochondria, cause depolarization of the mitochondrial membrane, and trigger the production of intracellular ROS. Additionally, the complexes were observed to induce late apoptosis and perturb the cell cycle in the G2/M or S phase in A549 cells. Based on these results, it appears that the anticancer efficacy of these complexes was predominantly attributed to the redox mechanism.

Potent Half-Sandwich 16-/18-Electron Iridium(III) and Ruthenium(II) Anticancer Complexes with Readily Available Amine-Imine Ligands

The synthesis and biological evaluation of stable 16-electron half-sandwich complexes have remained scarce. We herein present the different coordination modes (16-electron or 18-electron) between half-sandwich iridium(III) complexes and ruthenium(II) complexes derived from the same amine-imine ligands chelating hybrid sp3-N/sp2-N donors. The 16-electron iridium(III) and 18-electron ruthenium(II) complexes with different counteranions were obtained and identified by various techniques. The promising cytotoxicity of these complexes against A549 lung cancer cells, cisplatin-resistant A549/DPP cells, cervical carcinoma HeLa cells, and human hepatocellular liver carcinoma HepG2 cells was observed with IC50 values ranging from 5.4 to 16.3 μM. Moreover, these complexes showed a certain selectivity (selectivity index: 2.1-3.7) toward A549 cells and BEAS-2B normal cells. The variation of metal center, counteranion, 16/18-electron coordination mode, and ligand substituents showed little influence on the cytotoxicity and selectivity of these complexes. The mechanism of action study showed that these complexes could target mitochondria, induce the depolarization of the mitochondrial membrane, and promote the generation of intracellular reactive oxygen species (ROS). Further, the induction of cell apoptosis and the perturbation of the cell cycle in the G0/G1 phase were also observed for these complexes. Overall, it seems that the redox mechanism dominated the anticancer efficacy of these complexes.

Critical review of the phytochemical profiles and health-promoting effects of the edible mushroom Armillaria mellea

Research on the nutritional and medicinal properties of wild edible mushrooms has witnessed a significant surge in recent years. Among these mushrooms, Armillaria mellea (AM) stands out due to its abundant biologically active components. The presence of biological compounds in AM, including carbohydrates, sterols, fatty acids, sesquiterpenes, non-hallucinogenic indole compounds and adenosine derivatives, has been demonstrated in previous studies. Notably, specific bioactive substances isolated from AM, such as armillarikin, have exhibited promising anticancer effects. In vitro studies have elucidated the mechanisms behind these effects, further emphasizing the potential of AM in cancer treatment. Consequently, the objective of this study is to provide a comprehensive overview of the phytochemical profiles of AM while thoroughly investigating its therapeutic benefits. Moreover, this research has uncovered novel and effective treatments, including the utilization of ultrasonic disruption extraction in food processing. These findings highlight the potential of AM as a functional food with possible medical applications. By exploring AM's phytochemical composition and therapeutic effects, this study aims to contribute to a deeper understanding of its potential as a valuable natural resource.

Novel palladium(II) and Zinc(II) Schiff base complexes: Synthesis, biophysical studies, and anticancer activity investigation

BACKGROUND

Schiff base metal complexes are considered promising chemotherapeutic agents due to their potential application in cancer therapy.

METHODS

The current work sought to synthesize a brand-new Schiff base ligand obtained from 2-hydroxybenzohydrazide and (E)- 1-(2-(p-tolyl)hydrazono)propan-2-one with metal ions which included Pd(II) and Zn(II) ions. Elemental analyses, FT-IR, mass spectra, 1H NMR, UV-Vis spectrometer, and computational analysis characterized the compound's structure. In vitro, the breast cancer cell line (MCF-7) was tested for its sensitivity to Schiff base (HL) and its Pd(II) and Zn(II) complexes. The half-maximal inhibitory concentration IC₅₀ of the compounds was determined and used to perform the comet assay, which was carried out to reveal the photo-induced DNA damaging ability of the compounds of individual cells. Moreover, the compounds' effects on antioxidant defense systems of enzymes in cells: superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities and oxidant Malondialdehyde (MDA) were examined in MCF-7 cells.

RESULTS

The Pd(II) complex displayed approximately the same IC₅₀ as Cisplatin, while Zn(II) complex had better activity than Cisplatin with very low IC₅₀, 1.40 μg/ml. Significant alterations in SOD, CAT, GPx, and MDA production were discovered, inducing oxidative stress, enlarging ROS production, and reducing the antioxidant amount. This change was approximately similar in most compounds. Consequently, it promoted apoptosis, particularly the Zn(II) complex, which demonstrated an improved impact because of its ability to influence the antioxidant defense systems of enzymes, mostly SOD and GPx, besides increasing MDA levels.

CONCLUSION

It can be concluded that Zn(II) complex is the most effective anticancer drug since it induced a very similar genotoxic effect as Cisplatin and has a very low IC₅₀ value.

2-Hydroxypropyl-β-cyclodextrin (HPβCD) as a Potential Therapeutic Agent for Breast Cancer

Cholesterol accumulation is documented in various malignancies including breast cancer. Consequently, depleting cholesterol in cancer cells can serve as a viable treatment strategy. We identified the potency of 2-hydroxypropyl-β-cyclodextrin (HPβCD), a cholesterol-depletor in vitro against two breast cancer cell lines: MCF-7 (Oestrogen-receptor positive, ER+) and MDA-MB-231 (Triple negative breast cancer (TNBC)). The results were then compared against two non-cancerous cell lines using cytotoxic-, apoptosis-, and cholesterol-based assays. Treatment with HPβCD showed preferential and significant cytotoxic potential in cancer cells, inducing apoptosis in both cancer cell lines (p < 0.001). This was mediated due to significant depletion of cholesterol (p < 0.001). We further tested HPβCD in a MF-1 mice (n = 14) xenograft model and obtained 73.9%, 94% and 100% reduction in tumour size for late-, intermediate-, and early-stage TNBC, respectively. We also detected molecular-level perturbations in the expression patterns of several genes linked to breast cancer and cholesterol signalling pathways using RT²-PCR arrays and have identified SFRP1 as a direct binding partner to HPβCD through SPR drug interaction analysis. This work unravels mechanistic insights into HPβCD-induced cholesterol depletion, which leads to intrinsic apoptosis induction. Results from this study potentiate employing cholesterol depletion as a promising unconventional anticancer therapeutic strategy, which warrants future clinical investigations.

Antioxidants supplementation improves the quality of in vitro produced ovine embryos with amendments in key development gene expressions

The present study assessed the effects of supplementation of different antioxidants on oocyte maturation, embryo production, reactive oxygen species (ROS) production and expression of key developmental genes. In this study, using ovine as an animal model, we tested the hypothesis that antioxidant supplementation enhanced the developmental competence of oocytes. Ovine oocytes aspirated from local abattoir-derived ovaries were subjected to IVM with different concentrations of antioxidants [(Melatonin, Ascorbic acid (Vit C), alpha-tocopherol (Vit E), Sodium selenite (SS)]. Oocytes matured without any antioxidant supplementation were used as controls. The oocytes were assessed for maturation rates and ROS levels. Further, embryo production rates in terms of cleavage, blastocysts and total cell numbers were evaluated after performing in vitro fertilization. Real-Time PCR analysis was used to evaluate the expression of stress related gene (SOD-1), growth related (GDF-9, BMP-15), and apoptosis-related genes (BCL-2 and BAX). We observed that maturation rates were significantly higher in alpha-tocopherol (100 μM; 92.4%) groups followed by melatonin (30 μM; 89.1%) group. However, blastocyst rates in ascorbic acid (100 μM; 19.5%), melatonin (30 μM; 18.4%), alpha-tocopherol (100 μM; 18.2%), and sodium selenite (20 μM; 16.9%) groups were significantly higher (P 0.05) than that observed in the control groups. Total cell numbers in blastocysts in the melatonin, ascorbic acid and alpha-tocopherol groups were significantly higher than those observed in sodium selenite and control groups. ROS production was reduced in groups treated with melatonin (30 μM), vitamin C (100 μM), sodium selenite (20 μM) and α-tocopherol (200 μM) compared with that observed in the control group. Supplementation of antioxidants caused the alterations in mRNA expression of growth, stress, and apoptosis related gene expression in matured oocytes. The results recommend that antioxidants alpha-tocopherol (200 μM), sodium selenite (40 μM), melatonin (30 μM) and ascorbic acid (100 μM) during IVM reduced the oxidative stress by decreasing ROS levels in oocytes, thus improving embryo quantity and quality.

The Antioxidant and Proapoptotic Effects of Sternbergia clusiana Bulb Ethanolic Extract on Triple-Negative and Estrogen-Dependent Breast Cancer Cells In Vitro

BACKGROUND

Sternbergia clusiana belongs to the Amaryllidaceae family and is recognized for the valuable biological activity of its major bioactive compounds. The aim of the current is to evaluate the anticancer effects of the ethanolic bulb extract of Sternbergia clusiana (ScBEE) on breast cancer cells in vitro and to further reveal the underlying cellular mechanism.

METHODS

An MTS cell viability assay was performed on MDA-MB-231 and MCF-7 cells, along with cell cycle analysis, cell death ELISA, Western blot analysis and an ROS production assay to decipher the mechanism of death. LC-MS/MS was also performed to identify the chemical composition of this ethanolic extract.

RESULTS

The results show a selective antiproliferative effect on both cell lines with no effect on normal mesenchymal stem cells. Further analysis suggested the activation of the apoptotic pathway as reflected by the increase in cellular and DNA fragmentation and alterations in apoptotic proteins such as Bax, Bcl-2 and c-PARP. ScBEE was also found to exhibit antioxidant effect, as shown by a decrease in ROS production. The underlying mechanism of action was explained by the presence of several bioactive compounds identified by LC-MS/MS, including alkaloids, terpenoids and phenols, which are elaborated in the manuscript.

CONCLUSION

This study highlights the antioxidant and anticancerous properties of S.clusiana for breast cancer treatment.

Antitumor Potential of Sericite Treatment Mediated by Cell Cycle Arrest in Triple-Negative MDA-MB231 Breast Cancer Cells

Breast cancer is the most common cancer and the leading cause of cancer-related mortality among females worldwide. Triple-negative breast cancer (TNBC) accounts for about 10–15% of all breast cancers and is usually more aggressive and has a poorer prognosis. Sericite has been known to have antitumor and immune-stimulatory effects. Although the chemopreventive potential of sericite has been demonstrated in other cancers, its molecular pathways in TNBC still require investigation. Thus, in the present study, the antitumor mechanism of sericite against MDA-MB231 breast cancer cells was examined in vitro and in an in vivo xenograft mouse model. Sericite treatment reduced cell proliferation and cell proliferation marker proliferating cell nuclear antigen (PCNA) in MDA-MB231 cells. It also decreased the total cell number and arrested cells in the G0/G1 phase of the cell cycle with an increase in the phosphorylation of P53 and upregulation of cell cycle regulatory proteins P21 and P16. In addition, sericite treatment also induced apoptosis signaling, which was evident by the upregulation of apoptotic protein markers cleaved caspases 3 and 9. A reduction in reactive oxygen species (ROS), NADPH oxidase 4 (NOX4), p22phox, and heat shock proteins (HSPs) was also observed. Similar results were obtained in vivo with significantly reduced tumor volume in sericite-administered mice. Collectively, these findings suggest that sericite has antitumor potential based on its property to induce cell cycle arrest and apoptotic cell death and therefore could serve as a potential therapeutic agent and crucial candidate in anticancer drug development for TNBC.

The Impact of Oxidative Stress and AKT Pathway on Cancer Cell Functions and Its Application to Natural Products

Oxidative stress and AKT serine-threonine kinase (AKT) are responsible for regulating several cell functions of cancer cells. Several natural products modulate both oxidative stress and AKT for anticancer effects. However, the impact of natural product-modulating oxidative stress and AKT on cell functions lacks systemic understanding. Notably, the contribution of regulating cell functions by AKT downstream effectors is not yet well integrated. This review explores the role of oxidative stress and AKT pathway (AKT/AKT effectors) on ten cell functions, including apoptosis, autophagy, endoplasmic reticulum stress, mitochondrial morphogenesis, ferroptosis, necroptosis, DNA damage response, senescence, migration, and cell-cycle progression. The impact of oxidative stress and AKT are connected to these cell functions through cell function mediators. Moreover, the AKT effectors related to cell functions are integrated. Based on this rationale, natural products with the modulating abilities for oxidative stress and AKT pathway exhibit the potential to regulate these cell functions, but some were rarely reported, particularly for AKT effectors. This review sheds light on understanding the roles of oxidative stress and AKT pathway in regulating cell functions, providing future directions for natural products in cancer treatment.

Reactive Oxygen Species/Reactive Nitrogen Species as Messengers in the Gut: Impact on Physiology and Metabolic Disorders

Significance: The role of reactive oxygen/nitrogen species as "friend" or "foe" messengers in the whole body is well characterized. Depending on the concentration in the tissue considered, these molecular actors exert beneficial or deleterious impacts leading to a pathological state, as observed in metabolic disorders such as type 2 diabetes and obesity. Recent Advances: Among the tissues impacted by oxidation and inflammation in this pathological state, the intestine is a site of dysfunction that can establish diabetic symptoms, such as alterations in the intestinal barrier, gut motility, microbiota composition, and gut/brain axis communication. In the intestine, reactive oxygen/nitrogen species (from the host and/or microbiota) are key factors that modulate the transition from physiological to pathological signaling. Critical Issues: Controlling the levels of intestinal reactive oxygen/nitrogen species is a complicated balance between positive and negative impacts that is in constant equilibrium. Here, we describe the synthesis and degradation of intestinal reactive oxygen/nitrogen species and their interactions with the host. The development of novel redox-based therapeutics that alter these processes could restore intestinal health in patients with metabolic disorders. Future Directions: Deciphering the mode of action of reactive oxygen/nitrogen species in the gut of obese/diabetic patients could result in a future therapeutic strategy that combines nutritional and pharmacological approaches. Consequently, preventive and curative treatments must take into account one of the first sites of oxidative and inflammatory dysfunctions in the body, that is, the intestine. Antioxid. Redox Signal. 37, 394-415.

Anticancer potential of Phoenix dactylifera L. seed extract in human cancer cells and pro-apoptotic effects mediated through caspase-3 dependent pathway in human breast cancer MDA-MB-231 cells: an in vitro and in silico investigation

Background

Phoenix dactylifera L. has a diverse set of pharmacological properties due to its distinct phytochemical profile. The purpose of this study was to investigate the anticancer potential of Phoenix dactylifera seed extract (PDSE) in human breast cancer MDA-MB-231 and MCF-7 cells, as well as liver cancer HepG2 cells, and to investigate the anticancer efficacy in triple-negative MDA-MB-231 cells, followed by in silico validation of the molecular interaction between active components of PDSE and caspase-3, an apoptosis executioner protein .

Methods

In this study, human cancer cell lines were cultured and subsequently treated with 10 to 100 μg/mL of PDSE. MTT test was performed to determine the cell viability, MMP was measured using fluorescent probe JC-1, nuclear condensation was determined by Hoechst 33258 dye, Annexin V-FITC & PI staining and cell cycle analysis were evaluated through flow cytometer, and apoptotic markers were detected using western blotting. The bioactive agents in PDSE were identified using high-performance liquid chromatography (HPLC) analysis. The binding affinity was validated using molecular docking tools AutoDock Vina and iGEMDOCK v2.1.

Results

Cell viability data indicated that PDSE inhibited cell proliferation in both breast cancer cells and liver cancer cells. MDA-MB-231 cells showed maximum growth inhibition with an IC₅₀ value of 85.86 μg/mL for PDSE. However, PDSE did not show any significant toxicity against the normal Vero cell line. PDSE induced MMP loss and formation of apoptotic bodies, enhanced late apoptosis at high doses and arrested cells in the S phase of cell cycle. PDSE activated the enzymatic activity of cleaved caspase-3 and caused the cleavage of poly-ADB ribose polymerase (PARP) protein. PDSE upregulated pro-apoptotic Bax protein markedly but  no significant effect on tumor suppressor protein p53, while it downregulated the anti-apoptotic Bcl-2 protein expression. HPLC analysis showed the presence of rutin and quercetin bioactive flavonols in ethanolic extract of PDS. Interestingly, both active components revealed a strong binding interaction with amino acid residues of caspase-3 (PDB ID: 2XYP; Hetero 4-mer - A2B2) protein.

Conclusion

PDS could serve as a potential medicinal source for apoptotic cell death in human breast cancer cells and, thus, could be used as a promising and crucial candidate in anticancer drug development. This study warrants further in vivo research, followed by clinical investigation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03533-0.

Gallic Acid Enhances the Anti-Cancer Effect of Temozolomide in Human Glioma Cell Line via Inhibition of Akt and p38-MAPK Pathway

(1) Background: Temozolomide (TMZ), an oral alkylating agent, is used to treat malignant gliomas and other difficult-to-treat tumors. TMZ can enter the cerebrospinal fluid p.o. (per os) and does not need hepatic metabolism for activation of its use as a standard chemotherapeutic regimen after surgical resection of malignant glioma of the brain. However, the prognosis remains poor for most patients, and the survival rate is still unsatisfactory. Gallic acid (Ga) is a secondary metabolite existent in numerous plants. Ga shows various bioactivities, including antioxidant, anti-inflammatory, anticancer and antimicrobial effects. In this study, the latent enhanced anti-cancer efficacy of Ga in TMZ-treated U87MG cells (a human glioma line) was evaluated. (2) Methods: The U87MG cell line was cultured for 24 h. The cells were incubated with Ga alone, TMZ alone, or their combination for various time points. Cell viability and the drug combination index were evaluated by an XTT-based analysis and isobologram analysis, respectively. DNA destruction and intracellular reactive oxygen species (ROS) generation were analyzed by flow cytometer. The expression of various proteins was assessed via Western blotting. (3) Results: Compared with the action of TMZ alone or Ga alone, TMZ/Ga combination augmented the inhibition of cellular viability and apoptotic level in the U87MG glioma cell line. This enhanced anti-cancer effect correlated with the decreased expression of Bcl-2 and p-Akt, and corresponded with the activation of the p38 mitogen-activated protein kinase (MAPK) pathway. In addition, Ga suppressed the TMZ-promoted ROS generation. (4) Conclusions: Ga can augment the anti-cancer effect of TMZ via the repression of Bcl-2 expression and Akt activation and the enhancement of the p38 MAPK pathway. Our results offer a novel probable approach for the medical treatment of malignant glioma.

Antitumor Effects of Ir(III)-2H-Indazole Complexes for Triple Negative Breast Cancer

In this work, we have synthesized a series of novel C,N-cyclometalated 2H-indazole-ruthenium(II) and -iridium(III) complexes with varying substituents (H, CH₃, isopropyl, and CF₃) in the R₄ position of the phenyl ring of the 2H-indazole chelating ligand. All of the complexes were characterized by ¹H, ¹³C, high-resolution mass spectrometry, and elemental analysis. The methyl-substituted 2H-indazole-Ir(III) complex was further characterized by single-crystal X-ray analysis. The cytotoxic activity of new ruthenium(II) and iridium(III) compounds has been evaluated in a panel of triple negative breast cancer (TNBC) cell lines (MDA-MB-231 and MDA-MB-468) and colon cancer cell line HCT-116 to investigate their structure-activity relationships. Most of these new complexes have shown appreciable activity, comparable to or significantly better than that of cisplatin in TNBC cell lines. R₄ substitution of the phenyl ring of the 2H-indazole ligand with methyl and isopropyl substituents showed increased potency in ruthenium(II) and iridium(III) complexes compared to that of their parent compounds in all cell lines. These novel transition metal-based complexes exhibited high specificity toward cancer cells by inducing alterations in the metabolism and proliferation of cancer cells. In general, iridium complexes are more active than the corresponding ruthenium complexes. The new Ir(III)-2H-indazole complex with an isopropyl substituent induced mitochondrial damage by generating large amounts of reactive oxygen species (ROS), which triggered mitochondrion-mediated apoptosis in TNBC cell line MDA-MB-468. Moreover, this complex also induced G2/M phase cell cycle arrest and inhibited cellular migration of TNBC cells. Our findings reveal the key roles of the novel C-N-cyclometalated 2H-indazole-Ir(III) complex to specifically induce toxicity in cancer cell lines through contributing effects of ROS-induced mitochondrial disruption along with chromosomal and mitochondrial DNA target inhibition.

Alnustone inhibits the growth of hepatocellular carcinoma via ROS- mediated PI3K/Akt/mTOR/p70S6K axis

Alnustone, a diarylheptane compound, exhibits potent growth inhibition against hepatocellular carcinoma (HCC) BEL-7402 cells. However, the underlying mechanisms associated with its anticancer activity remain unknown. In the present study, we evaluated the anticancer effect of alnustone against several human cancers focused on HCC and the possible associated mechanisms. The results showed that alnustone significantly inhibited the growth of several cancer cells by CCK-8 assay. Alnustone markedly induced apoptosis and decreased mitochondrial membrane potential in BEL-7402 and HepG2 cells. Alnustone inhibited the expression of proteins related to apoptosis and PI3K/Akt/mTOR/p70S6K pathways and generated ROS production in BEL-7402 and HepG2 cells. Moreover, N-acetyl-L-cysteine (NAC, a ROS inhibitor) could significantly reverse the effects of alnustone on the growth inhibition of BEL-7402 and HepG2 cells and the expression of proteins related to apoptosis and PI3K/Akt/mTOR signaling pathway in HepG2 cells. Furthermore, alnustone significantly inhibited tumor growth of HepG2 xenografts, obviously induced apoptosis in the tumor tissues and improved the pathological condition of liver tissues of mice in vivo. The study provides evidence that alnustone is effective against HCC via ROS-mediated PI3K/Akt/mTOR/p70S6K pathway and the compound has the potential to be developed as a novel anticancer agent for the treatment of HCC clinically.

Safety and Efficacy Assessments to Take Antioxidants in Glioblastoma Therapy: From In Vitro Experiences to Animal and Clinical Studies

Glioblastoma (GBM) is considered one of the most common malignant brain tumors, occurring as over 15% of all primary central nervous system and brain neoplasms. The unique and standard treatment option towards GBM involves the combination of surgical resection followed by radiotherapy (RT) and chemotherapy (CT). However, due to the aggressive nature and heterogeneity of GBMs, they remained difficult to treat. Recent findings from preclinical studies have revealed that disruption of the redox balance via using either oxidative or anti-oxidative agents in GBM presented an effective and promising therapeutic approach. A limited number of clinical trials substantially encouraged their concomitant use with RT or CT. Thus, treatment of GBMs may benefit from natural or synthetic antioxidative compounds as novel therapeutics. Despite the presence of variegated in vitro and in vivo studies focusing on safety and efficacy issues of these promising therapeutics, nowadays their translation to clinics is far from applicability due to several challenges. In this review, we briefly introduce the enzymatic and non-enzymatic antioxidant defense systems as well as potential signaling pathways related to the pathogenesis of GBM with a special interest in antioxidant mechanisms. In addition, we describe the advantages and limitations of antioxidant supplementation in GBM cases or disease models as well as growing challenges for GBM therapies with antioxidants in the future.

Evaluation of potential toxicity of Steriplant©N aerosolization toward human alveolar cells A459 in vitro

Protection of patients against hospital-acquired infections is of major importance. Disinfection of magnetic resonance imaging suites is, due to their unique properties and environment particularly, difficult to implement. We developed an OPTI-JET CS MD 2ZE aerosolizator for disinfection of a magnetic resonance imaging suite using the electrolyzed oxidizing water biocide Steriplant^©N. The disinfection of the magnetic resonance imaging suite with this system reduced from the number of colony formed unit/m³ air by 87% and 96% in 6 and 15 min of disinfection, respectively. It is well known that exposure of personnel or patients to aerosols may represent risk to the respiratory system; therefore, the aim of this study was to assess potential cytotoxicity and genotoxicity of Steriplant^©N aerosolization toward human alveolar cells A459 in vitro. The A459 cells were exposed to aerosol containing different concentrations (50% and 100% v/v) of Steripalnt^©N for 6 min in a chamber that had been constructed to simulate the conditions in the magnetic resonance imaging suite. The cytotoxicity was evaluated by measuring iodide uptake, and the genotoxicity was determined by measuring formation of phosphorylated H2AX histones, a marker for deoxyribonucleic acid double-strand breaks, immediately after the aerosolization and after 1, 4, and 24 h postincubation. The results demonstrated that aerosolization with Steriplant^©N at conditions reflecting aerosolization in a magnetic resonance imaging suite is not cytotoxic and does not exhibit genotoxic potential in vitro.

Study of the Antioxidant Effects of Coffee Phenolic Metabolites on C6 Glioma Cells Exposed to Diesel Exhaust Particles

The contributing role of environmental factors to the development of neurodegenerative diseases has become increasingly evident. Here, we report that exposure of C6 glioma cells to diesel exhaust particles (DEPs), a major constituent of urban air pollution, causes intracellular reactive oxygen species (ROS) production. In this scenario, we suggest employing the possible protective role that coffee phenolic metabolites may have. Coffee is a commonly consumed hot beverage and a major contributor to the dietary intake of (poly) phenols. Taking into account physiological concentrations, we analysed the effects of two different coffee phenolic metabolites mixes consisting of compounds derived from bacterial metabolization reactions or phase II conjugations, as well as caffeic acid. The results showed that these mixes were able to counteract DEP-induced oxidative stress. The cellular components mediating the downregulation of ROS included extracellular signal-regulated kinase 1/2 (ERK1/2), nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and uncoupling protein 2 (UCP2). Contrary to coffee phenolic metabolites, the treatment with N-acetylcysteine (NAC), a known antioxidant, was found to be ineffective in preventing the DEP exposure oxidant effect. These results revealed that coffee phenolic metabolites could be promising candidates to protect against some adverse health effects of daily exposure to air pollution.

Natural and synthetic antioxidants targeting cardiac oxidative stress and redox signaling in cardiometabolic diseases

Cardiometabolic diseases (CMDs) are metabolic diseases (e.g., obesity, diabetes, atherosclerosis, rare genetic metabolic diseases, etc.) associated with cardiac pathologies. Pathophysiology of most CMDs involves increased production of reactive oxygen species and impaired antioxidant defense systems, resulting in cardiac oxidative stress (OxS). To alleviate OxS, various antioxidants have been investigated in several diseases with conflicting results. Here we review the effect of CMDs on cardiac redox homeostasis, the role of OxS in cardiac pathologies, as well as experimental and clinical data on the therapeutic potential of natural antioxidants (including resveratrol, quercetin, curcumin, vitamins A, C, and E, coenzyme Q10, etc.), synthetic antioxidants (including N-acetylcysteine, SOD mimetics, mitoTEMPO, SkQ1, etc.), and promoters of antioxidant enzymes in CMDs. As no antioxidant indicated for the prevention and/or treatment of CMDs has reached the market despite the large number of preclinical and clinical studies, a sizeable translational gap is evident in this field. Thus, we also highlight potential underlying factors that may contribute to the failure of translation of antioxidant therapies in CMDs.

Lutein Treatment Effects on the Redox Status and Metalloproteinase-9 (MMP-9) in Oral Cancer Squamous Cells-Are There Therapeutical Hopes?

Carotenoids loaded in nanoparticles should be regarded as a promising way to increase the availability in healthy cells and to induce apoptosis in cancer. Lutein is a carotenoid that, in contrast to beta-carotene, has no known toxicities. Oral cancer represents one of the most frequent types of cancer world-wide with an incidence rate of about 9% of all types of cancer. Almost 95% of all oral cancers are represented by squamous cell carcinomas (OSCC). The aim of this study was to review and analyse the effects of lutein and Poly(d,l-lactide-co-glycolide) (PLGA) Nps containing lutein (Lut Nps) on oxidative stress biomarkers (OXSR-1, FOXO-3, TAC) and collagen degradation biomarker-MMP-9, in human cells BICR10 of buccal mucosa squamous carcinoma. Lut Nps were prepared by the emulsion-solvent evaporation method. MMP, OXSR-1, TAC, FOXO-3 and MMP-9 were measured in tumour cell lysates by the ELISA technique. Our results have shown that in Lut 100 cells and Lut Nps the OXSR1 (p < 0.001, p < 0.001) and TAC (p < 0.001, p < 0.001) values were significantly higher than in control cells. The Lut 100 and Lut Nps FOXO-3 levels revealed no significant differences versus the control. MMP-9 levels were significantly reduced (p < 0.001) in the Lut Nps cells versus control cells. In our study conditions, lutein and lutein Nps did not trigger an oxidative stress by ROS induction. However, lutein Nps treatment seemed to have a positive effect, by downregulating the MMP-9 levels. Loaded in Nps, lutein could be regarded as a protective factor against local invasiveness, in whose molecular landscape MMPs, and especially MMP-9 are the main actors.

Deoxynivalenol downregulates NRF2-induced cytoprotective response in human hepatocellular carcinoma (HepG2) cells

Deoxynivalenol (DON) commonly infects agricultural foods; it exhibits toxicity by inducing oxidative stress and inhibiting protein synthesis. Nuclear factor erythroid 2-related factor 2 (NRF2) regulates the cellular antioxidant response. We investigated the cytotoxicity of DON and its effect on the NRF2 antioxidant response in HepG2 cells. The Methyl Thiazol Tetrazolium (MTT), glutathione (GSH) and ATP assays evaluated toxicity, whilst lipid peroxidation and membrane damage were assessed using the Thiobarbituric acid reactive substance (TBARS) and lactate dehydrogenase (LDH) assays. Protein expression of NRF2, phosphorylated (p-ser40) NRF2, catalase (CAT), superoxide dismutase 2 (SOD2), and Sirtuin 3 (Sirt3) were quantified by Western Blotting. Gene expression of glutathione peroxidase (GPx), CAT and SOD2 was determined using qPCR. DON decreased cell viability, GSH concentrations and ATP levels and increased lipid peroxidation and membrane damage. DON significantly decreased total NRF2 and increased p-NRF2 and downregulated the transcription and translation of NRF2 target antioxidant enzymes. Further, expression of the mitochondrial stress response protein, Sirt3 was significantly decreased. In conclusion, DON induced oxidative stress and downregulated NRF2-induced cytoprotection by suppressing the antioxidant signalling mechanism in HepG2 cells.

Silk Fibroin-Modified Disulfiram/Zinc Oxide Nanocomposites for pH Triggered Release of Zn2+ and Synergistic Antitumor Efficacy

Disulfiram (DSF) is an FDA-approved anti-alcoholic drug that has recently proven to be effective in cancer treatment. However, the short half-life in the bloodstream and the metal ion-dependent antitumor activity significantly limited the further application of DSF in the clinical field. To this end, we constructed a silk fibroin modified disulfiram/zinc oxide nanocomposites (SF/DSF@ZnO) to solubilize and stabilize DSF, and, more importantly, achieve pH triggered Zn²⁺ release and subsequent synergistic antitumor activity. The prepared SF/DSF@ZnO nanocomposites were spherical and had a high drug loading. Triggered by the lysosomal pH, SF/DSF@ZnO could induce the rapid release of Zn²⁺ under the acidic conditions and caused nanoparticulate disassembly along with DSF release. In vitro experiments showed that cytotoxicity of DSF could be enhanced by the presence of Zn²⁺, and further amplified when encapsulated into SF/DSF@ZnO nanocomposites. It was confirmed that the significantly amplified cytotoxicity of SF/DSF@ZnO was resulted from pH-triggered Zn²⁺ release, inhibited cell migration, and increased ROS production. In vivo study showed that SF/DSF@ZnO nanocomposites significantly increased the tumor accumulation and prolonged the retention time. In vivo antitumor experiments in the xenograft model showed that SF/DSF@ZnO exerted the highest tumor-inhibition rate among all the drug treatments. Therefore, this exquisite study established silk fibroin-modified disulfiram/zinc oxide nanocomposites, SF/DSF@ZnO, where ZnO not only acted as a delivery carrier but also served as a metal ion reservoir to achieve synergistic antitumor efficacy. The established DSF nanoformulation displayed excellent therapeutic potential in future cancer treatment.

Sulfhydryl groups as targets of mercury toxicity

The present study addresses existing data on the affinity and conjugation of sulfhydryl (thiol; -SH) groups of low- and high-molecular-weight biological ligands with mercury (Hg). The consequences of these interactions with special emphasis on pathways of Hg toxicity are highlighted. Cysteine (Cys) is considered the primary target of Hg, and link its sensitivity with thiol groups and cellular damage. In vivo, Hg complexes play a key role in Hg metabolism. Due to the increased affinity of Hg to SH groups in Cys residues, glutathione (GSH) is reactive. The geometry of Hg(II) glutathionates is less understood than that with Cys. Both Cys and GSH Hg-conjugates are important in Hg transport. The binding of Hg to Cys mediates multiple toxic effects of Hg, especially inhibitory effects on enzymes and other proteins that contain free Cys residues. In blood plasma, albumin is the main Hg-binding (Hg2+, CH3Hg+, C2H5Hg+, C6H5Hg+) protein. At the Cys34 residue, Hg2+ binds to albumin, whereas other metals likely are bound at the N-terminal site and multi-metal binding sites. In addition to albumin, Hg binds to multiple Cys-containing enzymes (including manganese-superoxide dismutase (Mn-SOD), arginase I, sorbitol dehydrogenase, and δ-aminolevulinate dehydratase, etc.) involved in multiple processes. The affinity of Hg for thiol groups may also underlie the pathways of Hg toxicity. In particular, Hg-SH may contribute to apoptosis modulation by interfering with Akt/CREB, Keap1/Nrf2, NF-κB, and mitochondrial pathways. Mercury-induced oxidative stress may ensue from Cys-Hg binding and inhibition of Mn-SOD (Cys196), thioredoxin reductase (TrxR) (Cys497) activity, as well as limiting GSH (GS-HgCH3) and Trx (Cys32, 35, 62, 65, 73) availability. Moreover, Hg-thiol interaction also is crucial in the neurotoxicity of Hg by modulating the cytoskeleton and neuronal receptors, to name a few. However, existing data on the role of Hg-SH binding in the Hg toxicity remains poorly defined. Therefore, more research is needed to understand better the role of Hg-thiol binding in the molecular pathways of Hg toxicology and the critical role of thiols to counteract negative effects of Hg overload.

Intracellular levels of reactive oxygen species correlate with ABT-263 sensitivity in non-small-cell lung cancer cells

ABT‐263 (Navitoclax) is a BH3‐mimetic drugs targeting anti‐apoptotic B‐cell lymphoma‐2 (BCL‐2) family proteins, including BCL‐2, BCL‐xL, and BCL‐w, thereby inducing apoptosis. In small‐cell lung cancer (SCLC) cells, the response to ABT‐263 is associated with the expression of myeloid cell leukemia‐1 (MCL‐1) protein, however the efficacy of ABT‐263 in non‐small‐cell lung cancer (NSCLC) has not been thoroughly evaluated. There are currently no established biomarkers for predicting the efficacy of ABT‐263 treatment in NSCLC. We screened a panel of different NSCLC cell lines and found that ABT‐263 inhibited cell proliferation and induced apoptosis in Calu‐1, Calu‐3, and BID007 cells. Inconsistent with previous reports on SCLC, low levels of MCL‐1 did not predict the response to ABT‐263 in NSCLC cells, however we found that intracellular levels of reactive oxygen species (ROS) in cancer cells were associated with sensitivity to ABT‐263 in NSCLC cells. We also showed that increasing the level of intracellular ROS could enhance the sensitivity to ABT‐263 in NSCLC cells. In summary, we propose that the intracellular levels of ROS could be used as a potential novel biomarker for predicting a response to ABT‐263 in NSCLC. Furthermore, we show some evidence supporting the further assessment of ABT‐263 as a new therapeutic strategy in patients with NSCLC combined with agents regulating ROS levels. We believe that our findings and follow‐up studies on this matter would lead to novel diagnostic and treatment strategies in patients with NSCLC.

Proapoptotic Effects of triazol-1,4-Naphthoquinones Involve Intracellular ROS Production and MAPK/ERK Pathway in Human Leukemia Cells

BACKGROUND

The natural products constitute an important source of antitumor and cytotoxic agents. Naphthoquinones are effectively quinones present in different plants, with demonstrated anticancer activities. A recent study conducted by our group demonstrated the antileukemic potential of two novel triazol-1,4- naphthoquinones derivatives, PTN (2-(4-Phenyl-1H-1,2,3-triazol-1-yl)-1,4-naphthoquinone) and MPTN (2-[4- (4-Methoxyphenyl)-1H-1,2,3-triazol-1-yl]-1,4-naphthoquinone). Although, the mechanisms underlying the proapoptotic effects of PTN and MPTN have not been fully elucidated so far.

OBJECTIVE

The aim of this study was to evaluate the proapoptotic mechanism of PTN and MPTN in human acute leukemia cells.

METHODS

We used fluorescence microscopy to observe acridine orange and annexin V staining cells. Flow cytometry assay has also been used for ROS quantification, BAX and cytochrome c proteins expression and apoptosis analysis. MTT assay and western blotting technique have been performed as well for MAPK pathway analysis.

RESULTS

By using the acridine orange and annexin V staining with fluorescence microscopy, we have characterized the proapoptotic effects of PTN and MPTN in HL-60 cells involving the intrinsic mitochondrial pathway, since these compounds promoted an increase in the intracellular BAX and cytochrome c protein levels (p<0.05). We further demonstrated that apoptosis induction in HL-60 cells was mediated by increasing intracellular ROS levels via ERK but not p38 MAPKs pathway.

CONCLUSION

Taken together, these results have demonstrated that PTN and MPTN are promising tools for the development of new anti-leukemic drugs.

Polyphenolic Composition and Anti-Melanoma Activity of White Forsythia (Abeliophyllum distichum Nakai) Organ Extracts

Abeliophyllum distichum Nakai, commonly called white forsythia, is a monotypic genus endemic to Korea. Although A. distichum is mainly used as an ornamental plant because of its horticultural value, recent studies have demonstrated its bioactivities, including antioxidant and anti-inflammatory activities, prompting us to investigate the potential anticancer effect of A. distichum organ extracts (leaves, fruit, and branches) against human melanoma SK-MEL-2 cells. The methanol extract of A. distichum leaves (AL) exhibited dose- and time-dependent cytotoxicities against SK-MEL-2 cells but not against HDFa human dermal fibroblasts. Based on high-performance liquid chromatography analysis, we identified 18 polyphenolic compounds from A. distichum organ extracts and suggest that differences in anticancer activity between organ extracts should be caused by different compositions of polyphenolic compounds. Additionally, the Annexin V/propidium iodide staining assay and analysis of caspase activity and expression indicated that AL induced cell death, including early and late apoptosis, as well as necrosis, by inducing the extrinsic pathway. Furthermore, we analyzed the differentially expressed genes between mock- and AL-treated cells using RNA-seq technology, suggesting that the anti-melanoma action of AL is mediated by down-regulation of the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway. Taken together, these results shed light on the potential use of A. distichum as a green resource with potent anti-melanoma activity.

A promising therapeutic combination for metastatic prostate cancer: Chloroquine as autophagy inhibitor and palladium(II) barbiturate complex

Autophagy is a catabolic process for cells that can provide energy sources and allows cancer cells to evade cell death. Therefore, studies on the combination of autophagy inhibitors with drugs are increasing as a new treatment modality in cancer. Previously, we reported the anti-tumor activity of a Palladium (Pd)(II) complex against different types of cancer in vitro and in vivo. Chloroquine (CQ), the worldwide used anti-malarial drug, has recently been focused as a chemosensitizer in cancer treatment. The aim of this study was to investigate the efficacy of a combined treatment of these agents that work through different mechanisms to provide an effective treatment modality for metastatic prostate cancer that is certainly fatal. Metastatic prostate cancer cell lines (PC-3 and LNCaP) were treated with Pd (II) complex, CQ, and their combination. The combination enhanced apoptosis by increasing phosphatidylserine translocation and pro-apoptotic proteins. Apoptosis was confirmed by the use of apoptosis inhibitor. The formation of acidic vesicular organelles (AVOs) was observed by acridine orange staining in fluorescence microscopy. The Pd (II) complex increased AVOs formation in prostate cancer cells and CQ-pretreatment has potentiated this effect. Importantly, treatment with CQ suppressed the pro-survival function of autophagy, which might have contributed to enhanced cytotoxicity. In addition, PI3K/AKT/mTOR-related protein expressions were altered after the combination of treatments. Our results suggest that combination treatment enhances apoptotic cell death possibly via the inhibition of autophagy, and may therefore be regarded as a novel and better approach for the treatment of metastatic prostate cancer.

Reactive oxygen species in reproduction: harmful, essential or both?

The process of embryonic development is crucial and radically influences preimplantation embryo competence. It involves oocyte maturation, fertilization, cell division and blastulation and is characterized by different key phases that have major influences on embryo quality. Each stage of the process of preimplantation embryonic development is led by important signalling pathways that include very many regulatory molecules, such as primary and secondary messengers. Many studies, both in vivo and in vitro, have shown the importance of the contribution of reactive oxygen species (ROS) as important second messengers in embryo development. ROS may originate from embryo metabolism and/or oocyte/embryo surroundings, and their effect on embryonic development is highly variable, depending on the needs of the embryo at each stage of development and on their environment (in vivo or under in vitro culture conditions). Other studies have also shown the deleterious effects of ROS in embryo development, when cellular tissue production overwhelms antioxidant production, leading to oxidative stress. This stress is known to be the cause of many cellular alterations, such as protein, lipid, and DNA damage. Considering that the same ROS level can have a deleterious effect on the fertilizing oocyte or embryo at certain stages, and a positive effect at another stage of the development process, further studies need to be carried out to determine the rate of ROS that benefits the embryo and from what rate it starts to be harmful, this measured at each key phase of embryonic development.

Quercetin Triggers Induction of Apoptotic and Lysosomal Death of Sensitive and Multidrug Resistant Leukaemia HL60 Cells

Multidrug resistance (MDR) constitutes the major cause of the failure in anticancer therapy. One of the most important mechanisms leading to the occurrence of MDR is related to the modulation of cellular death pathways. The aim of this study was to determine the effect of quercetin (Q) on triggering the programed death of human promyelocytic leukemia sensitive cells HL60 as well as multidrug resistant HL60/VINC cells overexpressing P-glycoprotein and HL60/MX2 cells characterized by the presence of mutated α isoform of topoisomerase II and the absence of β isoform of this enzyme. Q exerted comparable cytotoxic activities toward sensitive HL60 cells and their MDR counterparts. It was also found that this compound modulated the cellular level of reactive oxygen species (ROS) and led to the marked decrease in cellular GSH level. Furthermore, it was demonstrated that Q used at IC₅₀ and IC₉₀ significantly increased the percentage of sub-G1 subpopulation of all studied leukemia cells causing oligonucleosomal DNA fragmentation. The present study also indicated that Q used at IC₉₀ triggers predominantly programed cell death of sensitive HL60 cells and their MDR counterparts by induction of apoptosis occurring with the involvement of caspase-3 and caspase-8 as well as by lysosome membrane permeabilization-dependent mechanisms.

Oxidative stress regulates progenitor behavior and cortical neurogenesis

Orderly division of radial glial progenitors (RGPs) in the developing mammalian cerebral cortex generates deep and superficial layer neurons progressively. However, the mechanisms that control RGP behavior and precise neuronal output remain elusive. Here, we show that the oxidative stress level progressively increases in the developing mouse cortex and regulates RGP behavior and neurogenesis. As development proceeds, numerous gene pathways linked to reactive oxygen species (ROS) and oxidative stress exhibit drastic changes in RGPs. Selective removal of PRDM16, a transcriptional regulator highly expressed in RGPs, elevates ROS level and induces expression of oxidative stress-responsive genes. Coinciding with an enhanced level of oxidative stress, RGP behavior was altered, leading to abnormal deep and superficial layer neuron generation. Simultaneous expression of mitochondrially targeted catalase to reduce cellular ROS levels significantly suppresses cortical defects caused by PRDM16 removal. Together, these findings suggest that oxidative stress actively regulates RGP behavior to ensure proper neurogenesis in the mammalian cortex.

Ginger extract ameliorates bisphenol A (BPA)-induced disruption in thyroid hormones synthesis and metabolism: Involvement of Nrf-2/HO-1 pathway

Environmental exposure to BPA is alarming because of the potential health threats for example those concerning the thyroid glands which may show signs of oxidative stress. This original study aimed to investigate the possible antioxidant protective effects of ginger extract (GE) against BPA-induced thyroid injury in male rats, focusing on its effect on Nrf-2/HO-1 signaling and thyroid hormone synthesis regulating genes. The cascade of events in thyroid injury induced by chronic exposure to BPA (200 mg/kg b.w/day for 35 days) involved a preliminary overproduction of ROS followed by significant (p ≤ 0.05) depletion of reduced glutathione (GSH) levels and superoxide dismutase (SOD) activity as well as significant increases of malondialdehyde (MDA) contents, myeloperoxidase (MPO) activity and inducible nitric oxide synthase (iNOS) gene expression. These actions consequently down-regulate the Nrf-2/HO-I signaling which eventually resulting in the DNA fragmentation within the thyroid tissues. Moreover, BPA administration caused a reduction of thyroid iodide uptake evidenced by significant inhibitions (p ≤ 0.05) of sodium-iodide symporter (NIS), thyroid peroxidase (TPO) and thyroid-stimulating hormone receptor (TSHR) mRNA expressions within the thyroid glands. A subsequent significant decreased serum levels of T3 and T4 accompanied by a significantly increased serum TSH level were also detected. These findings were confirmed by the severe pathological changes detected in the thyroid tissue of BPA treated rats. These biochemical and histological alterations were significantly alleviated with ginger administration (250 mg/kg b.w/day for 35 days) plus BPA. In conclusion, ginger extract is a potent antioxidant that can effectively protect against BPA-induced thyroid oxidative damage by activating the Nrf-2/HO-1 gene expressions and enhancing the thyroid hormones synthesis. This is the first study to show the contribution of Nrf-2/HO-1 pathway to the protective effect of ginger extract against BPA-induced thyroid oxidative damage and thyroid hormonal disruption.

Use of zebrafish larvae lateral line to study protection against cisplatin-induced ototoxicity: A scoping review

AIM

The present review aimed to consolidate and analyze the recent information about the use of zebrafish in studies concerning cisplatin-induced ototoxicity and otoprotection.

MATERIAL AND METHODS

The PubMed, Web of Science, and Scopus databanks were searched using the following MESH terms: zebrafish, cisplatin, ototoxicity. The identified publications were screened according to inclusion and exclusion criteria and the 26 qualifying manuscripts were included in the full-text analysis. The experimental protocols, including cisplatin concentrations, the exposure duration and the outcome measurements used in zebrafish larvae studies, were evaluated and the reported knowledge was summarized.

RESULTS

Twenty-six substances protecting from cisplatin-induced toxicity were identified with the use of zebrafish larvae. These substances include quinine, salvianolic acid B, berbamine 6, benzamil, quercetin, dexmedetomidine, dexamethsanone, quinoxaline, edaravone, apocynin, dimethyl sulfoxide, KR-22335, SRT1720, ORC-13661, 3-MA, D-methionine, mdivi-1, FUT-175, rapamycin, Z-LLF-CHO, ATX, NAC, CYM-5478, CHCP1, CHCP2 and leupeptin. The otoprotective effects of compounds were attributed to their anti-ROS, anti-apoptotic and cisplatin uptake-blocking properties. The broadest range of protection was achieved when the experimental flow used preconditioning with an otoprotective compound and later a co-incubation with cisplatin. Protection against a high concentration of cisplatin was observed only in protocols using short exposure times (4 and 6 h).

CONCLUSIONS

The data extracted from the selected papers confirm that despite the differences between the human and the zebra fish hearing thresholds (as affected by cisplatin), the sensory cells of zebrafish and larval zebrafish are a valuable tool which could be used: (i) for the discovery of novel otoprotective substances and compounds; (ii) to screen their side effects and (iii) to extend the knowledge on the mechanisms of cisplatin-induced inner ear damage. For future studies, the development of a consensus experimental protocol is highly recommended.

Protective Effects of Aqueous Extract of Mentha suaveolens against Oxidative Stress-Induced Damages in Human Keratinocyte HaCaT Cells

Mentha suaveolens is an aromatic herb that has a wide range of biological activities, including antimicrobial, antifungal, anti-inflammatory, and hepatoprotective properties. Although there are a few reports on the antioxidant property of M. suaveolens, its cytoprotective activity against oxidative stress has not been reported yet. The objective of this study was to determine the protective activity of M. suaveolens aqueous extract (MSAE) against hydrogen peroxide- (H₂O₂-) induced oxidative stress and apoptosis in human keratinocyte HaCaT cells. MSAE pretreatment decreased H₂O₂-induced cytotoxicity and suppressed H₂O₂-induced intracellular ROS generation. Furthermore, MSAE suppressed expression levels of H₂O₂-induced apoptotic genes such as cleaved caspase-3, caspase-9, and cleaved poly (ADP-ribose) polymerase (PARP). Pretreatment with MSAE induced expression of phase II enzyme such as HO-1 through translocation of NF-E2-related factor (Nrf2) upon H₂O₂ exposure. These results revealed that the cytoprotective effect of MSAE against oxidative stress-induced cell death was associated with activation of Nrf2-mediated phase II enzyme expression.

Apoptotic Pathway as the Therapeutic Target for Anticancer Traditional Chinese Medicines

Cancer is a leading cause of morbidity and mortality worldwide. Apoptosis is a process of programmed cell death and it plays a vital role in human development and tissue homeostasis. Mounting evidence indicates that apoptosis is closely related to the survival of cancer and it has emerged as a key target for the discovery and development of novel anticancer drugs. Various studies indicate that targeting the apoptotic signaling pathway by anticancer drugs is an important mechanism in cancer therapy. Therefore, numerous novel anticancer agents have been discovered and developed from traditional Chinese medicines (TCMs) by targeting the cellular apoptotic pathway of cancer cells and shown clinically beneficial effects in cancer therapy. This review aims to provide a comprehensive discussion for the role, pharmacology, related biology, and possible mechanism(s) of a number of important anticancer TCMs and their derivatives mainly targeting the cellular apoptotic pathway. It may have important clinical implications in cancer therapy.

ROS-Mediated Cancer Cell Killing through Dietary Phytochemicals

Reactive oxygen species (ROS) promote carcinogenesis by inducing genetic mutations, activating oncogenes, and raising oxidative stress, which all influence cell proliferation, survival, and apoptosis. Cancer cells display redox imbalance due to increased ROS level compared to normal cells. This unique feature in cancer cells may, therefore, be exploited for targeted therapy. Over the past few decades, natural compounds have attracted attention as potential cancer therapies because of their ability to maintain cellular redox homeostasis with minimal toxicity. Preclinical studies show that bioactive dietary polyphenols exert antitumor effects by inducing ROS-mediated cytotoxicity in cancer cells. These bioactive compounds also regulate cell proliferation, survival, and apoptotic and antiapoptotic signalling pathways. In this review, we discuss (i) how ROS is generated and (ii) regulated and (iii) the cell signalling pathways affected by ROS. We also discuss (iv) the various dietary phytochemicals that have been implicated to have cancer therapeutic effects through their ROS-related functions.

Development of near-infrared region luminescent N-acetyl-L-cysteine-coated Ag2S quantum dots with differential therapeutic effect

AIM

N-acetyl-L-cysteine (NAC) is a free radical scavenger. We developed NAC-coated Ag₂S (NAC-Ag₂S) quantum dot (QD) as an optical imaging and therapeutic agent.

MATERIALS & METHODS

QDs were synthesized in water. Their optical imaging potential and toxicity were studied in vitro.

RESULTS

NAC-Ag₂S QDs have strong emission, that is tunable between 748 and 840 nm, and are stable in biologically relevant media. QDs showed significant differences both in cell internalization and toxicity in vitro. QDs were quite toxic to breast and cervical cancer cells but not to lung derived cells despite the higher uptake. NAC-Ag₂S reduces reactive oxygen species (ROS) but causes cell death via DNA damage and apoptosis.

CONCLUSION

NAC-Ag₂S QDs are stable and strong signal-generating theranostic agents offering selective therapeutic effects.

Liposomal Curcumin is Better than Curcumin to Alleviate Complications in Experimental Diabetic Mellitus

Curcumin (CC) is known to have anti-inflammatory and anti-oxidative properties and has already been tested for its efficiency in different diseases including diabetes mellitus (DM). New formulations and route administration were designed to obtain products with higher bioavailability. Our study aimed to test the effect of intraperitoneal (i.p.) administration of liposomal curcumin (lCC) as pre-treatment in streptozotocin(STZ)-induced DM in rats on oxidative stress, liver, and pancreatic functional parameters. Forty-two Wistar-Bratislava rats were randomly divided into six groups (seven animals/group): control (no diabetes), control-STZ (STZ-induced DM —60 mg/100g body weight a single dose intraperitoneal administration, and no CC pre-treatment), two groups with DM and CC pre-treatment (1mg/100g bw—STZ + CC1, 2 mg/100g bw—STZ + CC2), and two groups with DM and lCC pre-treatment (1 mg/100g bw—STZ + lCC1, 2 mg/100g bw—STZ + lCC1). Intraperitoneal administration of Curcumin in diabetic rats showed a significant reduction of nitric oxide, malondialdehyde, total oxidative stress, and catalase for both evaluated formulations (CC and lCC) compared to control group (p < 0.005), with higher efficacy of lCC formulation compared to CC solution (p < 0.002, excepting catalase for STZ + CC2vs. STZ + lCC1when p = 0.0845). The CC and lCC showed hepatoprotective and hypoglycemic effects, a decrease in oxidative stress and improvement in anti-oxidative capacity status against STZ-induced DM in rats (p < 0.002). The lCC also proved better efficacy on MMP-2, and -9 plasma levels as compared to CC (p < 0.003, excepting STZ + CC2 vs. STZ + lCC1 comparison with p = 0.0553). The lCC demonstrated significantly better efficacy as compared to curcumin solution on all serum levels of the investigated markers, sustaining its possible use as adjuvant therapy in DM.

The Delicate Equilibrium between Oxidants and Antioxidants in Brain Glioma

Gliomas are the most frequent brain tumors in the adult population and unfortunately the adjuvant therapies are not effective. Brain tumorigenesis has been related both to the increased levels of free radicals as inductors of severe damages in healthy cells, but also with the reduced response of endogenous enzyme and non-enzymatic antioxidant defenses. In turn, both processes induce the change to malignant cells. In this review, we analyzed the role of the imbalance between free radicals production and antioxidant mechanism in the development and progression of gliomas but also the influence of redox status on the two major distinctive forms of programmed cell death related to cancer: apoptosis and autophagy. These data may be the reference to the development of new pharmacological options based on redox microenvironment for glioma treatment.

What Has Come out from Phytomedicines and Herbal Edibles for the Treatment of Cancer?

Several modern treatment strategies have been adopted to combat cancer with the aim of minimizing toxicity. Medicinal plant-based compounds with the potential to treat cancer have been widely studied in preclinical research and have elicited many innovations in cutting-edge clinical research. In parallel, researchers have eagerly tried to decrease the toxicity of current chemotherapeutic agents either by combining them with herbals or in using herbals alone. The aim of this article is to present an update of medicinal plants and their bioactive compounds, or mere changes in the bioactive compounds, along with herbal edibles, which display efficacy against diverse cancer cells and in anticancer therapy. It describes the basic mechanism(s) of action of phytochemicals used either alone or in combination therapy with other phytochemicals or herbal edibles. This review also highlights the remarkable synergistic effects that arise between certain herbals and chemotherapeutic agents used in oncology. The anticancer phytochemicals used in clinical research are also described; furthermore, we discuss our own experience related to semisynthetic derivatives, which are developed based on phytochemicals. Overall, this compilation is intended to facilitate research and development projects on phytopharmaceuticals for successful anticancer drug discovery.

Development of genistein-PEGylated silica hybrid nanomaterials with enhanced antioxidant and antiproliferative properties on HT29 human colon cancer cells

The anticancer use of genistein (Gen) has been severely limited due to its low water solubility, low bioavailability, and instability under experimental conditions. To overcome these limitations, we propose a formulation of a hybrid nanomaterial (HNM) based upon the incorporation of Gen into PEGylated silica nanoparticles (PEG-SiNPs) (Gen-PEG-SiHNM), where their physicochemical and biological effects on HT29 cells were evaluated. Genistein-loaded PEGylated silica hybrid nanomaterials were obtained by a simple end effective aqueous dispersion method. Physicochemical properties were determined by its mean particle size, surface charge, amount of cargo, spectroscopic properties, release profiles and aqueous solubility. In vitro biological performance was carried out by evaluating its antioxidant capacity and elucidating its antiproliferative mechanistic. Results showed that small (ca. 33 nm) and spherical particles were obtained with positive surface charge (+9.54 mV). Infrared analyses determined that encapsulation of genistein was successfully achieved with an efficiency of 51%; it was observed that encapsulation process enhanced the aqueous dispersibility of genistein and cumulative release of genistein was pH-dependent. More important, after encapsulation data showed that Gen potentiated its antioxidant and antiproliferative effects on HT29 human colon cancer cells by the modulation of endogenous antioxidant enzymes and H₂O₂ production, which simultaneously activated two different processes of cell death (apoptosis and autophagy), unlike free genistein that only activated one (apoptosis) in a lower proportion. Overall, our data support that Gen-PEG-SiHNM could be potentially used as alternative treatment for colorectal cancer in a near future.