ROS-mediated Mitogen-activated Protein Kinase Research Articles

Network pharmacology analysis and experimental verification of the antitumor effect and molecular mechanism of isocryptomerin on HepG2 cells.

Isocryptomerin (ISO) is a flavonoid isolated from the natural medicine Selaginellae Herba, which has various pharmacological activities. This study investigated the antitumor effect and underlying molecular mechanism of ISO on hepatocellular carcinoma (HCC) HepG2 cells. The cell viability assay revealed that ISO has a considerable killing effect on HCC cell lines. The apoptosis assay showed that ISO induced mitochondria-dependent apoptosis through the Bad/cyto-c/cleaved (cle)-caspase-3/cleaved (cle)-PARP pathway. The network pharmacological analysis found 13 key target genes, and epidermal growth factor receptor (EGFR), AKT, mitogen-activated protein kinase(MAPK), and reactive oxygen species (ROS) signaling pathways were strongly associated with ISO against HCC. Further verification of the results showed that ISO induced apoptosis by increasing p-p38 and p-JNK expression and decreasing p-EGFR, p-SRC, p-ERK, and p-STAT3 expression. Furthermore, ISO induced G0/G1 phase arrest by downregulating p-AKT, Cyclin D, and CDK 4 expression and upregulating p21 and p27 expression in HepG2 cells. Moreover, ISO inhibited HepG2 cell migration by decreasing p-GSK-3β, β-catenin, and N-cadherin expression and increasing E-cadherin expression. Additionally, ISO promoted ROS accumulation in HepG2 cells, and ISO-induced apoptosis, arrest cell cycle, and inhibition of migration were reversed by an ROS scavenger, N-acetyl- l-cysteine. Overall, ISO induced cell apoptosis and cell cycle arrest and inhibited cell migration by ROS-mediated EGFR, AKT, and MAPK signaling pathways in HepG2 cells.

Schisandrin B exerts anticancer effects on human gastric cancer cells through ROS-mediated MAPK, STAT3, and NF-κB pathways

Schisandrin B (Sch B) is a monomer with anti-cancer and anti-inflammatory effects, which are isolated from the plant Schisandra chinensis (Turcz) Baillon. We investigated the anti-gastric cancer (GC) effects of Sch B and its underlying molecular mechanisms. The Cell Counting Kit-8 assay was used to determine the effects of Sch B on the viability of GC and normal cell lines. Hoechst/propidium iodide staining and flow cytometry were used to assess the apoptosis induction of Sch B. Western blotting was used to evaluate the effects of Sch B on downstream apoptotic proteins. The DCFH-DA fluorescent probe was used to assess the regulatory effects of Sch B on reactive oxygen species (ROS) levels and related signaling pathways in GC cells. The results showed that Sch B could regulate the phosphorylation level of mitogen-activated protein kinase (MAPK) by upregulating ROS accumulation in gastric cancer cells, and then reduce the expression of nuclear factor kappa B (NF-κB) and phosphorylated transcription 3 (p-STAT3). In addition, Sch B downregulated the cell cycle proteins cyclin-dependent kinase 2/4/6 and cyclin D1/E, and arrested cells in the G0/G1 phase. Moreover, it also inhibited cell migration, which was reversed with Nacetylcysteine pretreatment. In summary, Sch B has killing effects on GC cells by upregulating the production of intracellular ROS and regulating the MAPK/STAT3/NF-κB signaling pathway, leading to the migration arrest and apoptosis of GC cells.

Cystathionine γ-lyase mediates cell proliferation, migration, and invasion of nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is an epithelia-derived malignancy with a distinctive geographic distribution. Cystathionine γ-lyase (CSE) is involved in cancer development and progression. Nevertheless, the role of CSE in the growth of NPC is unknown. In this study, we found that CSE levels in human NPC cells were higher than those in normal nasopharyngeal cells. CSE overexpression enhanced the proliferative, migrative, and invasive abilities of NPC cells and CSE downregulation exerted reverse effects. Overexpression of CSE decreased the expressions of cytochrome C, cleaved caspase (cas)-3, cleaved cas-9, and cleaved poly-ADP-ribose polymerase, whereas CSE knockdown exhibited reverse effects. CSE overexpression decreased reactive oxygen species (ROS) levels and the expressions of phospho (p)-extracellular signal-regulated protein kinase 1/2, p-c-Jun N-terminal kinase, and p-p38, but promoted the expressions of p-phosphatidylinositol 3-kinase (PI3K), p-AKT, and p-mammalian target of rapamycin (mTOR), whereas CSE knockdown showed oppose effects. In addition, CSE overexpression promoted NPC xenograft tumor growth and CSE knockdown decreased tumor growth by modulating proliferation, angiogenesis, cell cycle, and apoptosis. Furthermore, DL-propargylglycine (an inhibitor of CSE) dose-dependently inhibited NPC cell growth via ROS-mediated mitogen-activated protein kinase (MAPK) and PI3K/AKT/mTOR pathways without significant toxicity. In conclusion, CSE could regulate the growth of NPC cells through ROS-mediated MAPK and PI3K/AKT/mTOR cascades. CSE might be a novel tumor marker for the diagnosis and prognosis of NPC. Novel donors/drugs that inhibit the expression/activity of CSE can be developed in the treatment of NPC.

1'-Acetoxyeugenol Acetate Isolated from Thai Ginger Induces Apoptosis in Human Ovarian Cancer Cells by ROS Production via NADPH Oxidase.

The rhizomes of Alpinia galanga (Thai ginger) have been used extensively as a spice in Southeast Asian and Arabian cuisines and reported to possess a wide range of biological properties, such as antioxidant, antimicrobial, and antibacterial. However, the specific molecular and cellular mechanisms underlying the anti-tumor effects induced by Thai ginger and its corresponding active compounds have been poorly characterized. We found that upon EtOH extraction, Thai ginger extract exhibits cytotoxic activity (IC50 < 10 μg/mL) and triggers cell death via caspase-dependent apoptosis in human ovarian cancer cells. Among the three major compounds isolated from the extract, 1′-acetoxyeugenol acetate (AEA) exhibited potent cytotoxic activity in human ovarian cancer cells, SKOV3 and A2780. AEA induced apoptotic cell death through the activation of caspases-3 and -9. Notably, AEA enhanced the intracellular levels of reactive oxygen species (ROS), and the application of an antioxidant markedly reversed AEA-induced apoptosis of ovarian cancer cells. The knockdown of p47phox, a subunit of NADPH oxidase, suppressed both the pro-apoptotic and ROS-inducing effects of AEA. Additionally, the activation of the mitogen-activated protein kinase (MAPK) pathway by AEA through ROS regulation was found to be involved in AEA-induced apoptosis. Altogether, these results suggest that AEA exhibits potent apoptosis-inducing activity through the activation of the intrinsic pathway via ROS-mediated MAPK signaling in human ovarian cancer cells.

CHIP-overexpressing Wharton's jelly-derived mesenchymal stem cells attenuate hyperglycemia-induced oxidative stress-mediated kidney injuries in diabetic rats

Accumulating studies have demonstrated the protective roles of mesenchymal stem cells against several disorders. However, one of their crucial limitations is reduced viability under stress conditions, including the hyperglycemia induced by diabetes. The molecular mechanisms involved in diabetes-induced kidney injuries are not fully elucidated. In this study, we found that high glucose (HG) reduced human proximal tubular epithelial cell viability. Further, hyperglycemia induced oxidative stress-mediated apoptosis and fibrosis in HK-2 cells via activation of the mitogen-activated protein kinases (MAPKs) including c-Jun N-terminal kinase JNK and p38 kinase. Carboxyl terminus of HSP70 interacting protein (CHIP) overactivation considerably rescued cell viability under HG stress. Moreover, Western blot analysis, flow cytometry, and MitoSOX staining revealed that hyperglycemia-induced mitochondrial oxidative stress production and apoptosis were attenuated in CHIP-overexpressing Wharton's jelly-derived mesenchymal stem cells (WJMSCs). Co-culture with CHIP-expressing WJMSCs maintained HK-2 cell viability, and inhibited apoptosis and fibrosis by attenuating HG-induced ROS-mediated MAPK activation. CHIP-overexpressing WJMSCs also rescued the decreased kidney weight and hyperglycemia-induced kidney damage observed in streptozotocin-induced diabetic rats. Cumulatively, the current research findings demonstrate that CHIP suppresses hyperglycemia-induced oxidative stress and confers resistance to MAPK-induced apoptosis and fibrosis, and suggests that CHIP protects WJMSCs and the high quality WJMSCs have therapeutic effects against diabetes-induced kidney injuries.

10-HDA Induces ROS-Mediated Apoptosis in A549 Human Lung Cancer Cells by Regulating the MAPK, STAT3, NF-κB, and TGF-β1 Signaling Pathways.

10-Hydroxy-2-decenoic acid (10-HDA), also known as royal jelly acid, has a variety of physiological functions, and recent studies have shown that it also has anticancer effects. However, its anticancer mechanisms have not been clearly defined. In this study, we investigated the underlying mechanisms of 10-HDA in A549 human lung cancer cells. We used Cell Counting Kit-8 assay, scratch wound healing assay, flow cytometry, and western blot analysis to investigate its apoptotic effects and underlying mechanism. Our results showed that 10-HDA inhibited the proliferation of three types of human lung cancer cells and had no significant toxic effects on normal cells. Accompanying reactive oxygen species (ROS), 10-HDA induced A549 cell apoptosis by regulating mitochondrial-associated apoptosis, and caused cell cycle arrest at the G0/G1 phase in a time-dependent manner. Meanwhile, 10-HDA also regulated mitogen-activated protein kinase (MAPK), signal transducer and activator of transcription 3 (STAT3), and nuclear factor kappa B (NF-κB) signaling pathways by increasing the expression levels of phosphorylated c-Jun N-terminal kinase, p-p38, and I-κB, and additionally, by decreasing the expression levels of phosphorylated extracellular signal-regulated kinase, p-STAT3, and NF-κB. These effects were blocked by MAPK inhibitors and N-acetyl-L-cysteine. Furthermore, 10-HDA inhibited cell migration by regulating transforming growth factor beta 1 (TGF-β1), SNAI1, GSK-3β, E-cadherin, N-cadherin, and vimentin. Taken together, the results of this study showed that 10-HDA induced cell cycle arrest and apoptosis in A549 human lung cancer cells through ROS-mediated MAPK, STAT3, NF-κB, and TGF-β1 signaling pathways. Therefore, 10-HDA may be a potential therapy for human lung cancer.

Kaempferide Induces G0/G1 Phase Arrest and Apoptosis via ROS-Mediated Signaling Pathways in A549 Human Lung Cancer Cells

Kaempferide is an O-methylated flavonol that has received much attention due to its various biological activities. In this study, we explored the underlying mechanisms of kaempferide in human lung cancer A549 cells. The Cell Counting Kit-8 (CCK-8) assay, Hoechst 33342/propidium iodide double staining, flow cytometry, scratch wound healing assay, and Western blot analysis were used to measure cell apoptosis, the cell cycle, reactive oxygen species (ROS) levels, and cell migration of human lung cancer cells. Kaempferide significantly inhibited human lung cancer cell proliferation, and its toxic effects on normal cells were significantly lower than those of 5-fluorouracil. Kaempferide induced A549 cell apoptosis by decreasing the mitochondrial membrane potential and the expression level of B-cell lymphoma 2, and by increasing the expression levels of Bcl-2-associated X protein and caspase-3. It also regulated mitogen-activated protein kinase (MAPK), signal transducer and activator of transcription 3 (STAT3), and nuclear factor kappa B (NF-κB) signaling pathways by increasing the expression levels of phosphorylated c-Jun N-terminal kinase, p-p38, I kappa B, and by decreasing the expression levels of phosphorylated extracellular signal-regulated kinase, p-STAT3, and NF-κB. Kaempferide induced cell cycle arrest in the G0/G1 phase in A549 cells by downregulating the expression levels of p-AKT, cyclin D1, and cyclin-dependent kinase 2. Furthermore, kaempferide blocked A549 cell migration by downregulating the expression levels of transforming growth factor beta 1 (TGF-β1), p-β-catenin, p-glycogen synthase kinase 3 beta, N-cadherin, and vimentin, and by upregulating the expression level of E-cadherin. Kaempferide enhanced the accumulation of ROS, and N-acetyl-l-cysteine (a ROS inhibitor) decreased the regulation of MAPK, NF-κB, AKT, and TGF-β signaling pathways by kaempferide, inhibited cell apoptosis, and reversed cell cycle arrest. Our results showed that kaempferide induced apoptosis via ROS-mediated MAPK, NF-κB, AKT, and TGF-β signaling pathways in A549 cells. Thus, kaempferide may be a novel drug candidate for lung cancer.

Colonization of Trichoderma viride Tv-1511 in peppermint (Mentha × piperita L.) roots promotes essential oil production by triggering ROS-mediated MAPK activation

Peppermint (Mentha × piperita L.) is a flavoring additive used worldwide, and Trichoderma species are beneficial fungi that can stimulate growth and disease resistance of these plants. Here the growth conditions and metabolic processes of essential oil (EO) biosynthesis in response to inoculation with Trichoderma viride Tv-1511 were investigated. The results showed that T. viride Tv-1511 was able to colonize roots of peppermint to promote its growth and photosynthetic activity and induce higher levels of glandular trichomes and elevated EO yield and composition. GC-MS analysis showed that T. viride Tv-1511-inoculated peppermint produced higher concentrations of menthone, menthol, and pulegone and lower concentrations of menthofuran than un-inoculated seedlings, and qRT-PCR showed that T. viride Tv-1511 inoculation induced upregulation of Pr (pulegone reductase encoding gene) and Mr (menthone reductase encoding gene), whereas it led to the downregulation of Mfs (menthofuran synthase encoding gene). Furthermore, a mitogen-activated protein kinase (MAPK) in peppermint, which was determined to be an analog of Arabidopsis MPK6 protein, was found to be responsible for the modulation of EO metabolism at the transcriptional level and for enzymatic activation in the T. viride Tv-1511-inoculated peppermint. Notably, NADPH oxidase-dependent reactive oxygen species (ROS) production played vital roles in the root colonization of T. viride Tv-1511 and was also involved in the induction of MAPK activation. These data showed the beneficial effects of T. viride Tv-1511 on the seedling growth and EO yield of peppermint, and they elucidated that T. viride Tv-1511 improved the quantity and quality of EOs by regulating the genes that encode the enzymes involved in EO metabolism through a potential MAPK-mediated signaling pathways.

Influence of PM2.5 on spermatogenesis dysfunction via the reactive-oxygen-species-mediated Mitogen-activated-protein-kinase signaling pathway

Approximately 15 % of the world‘s couples confront childless, and about 50 % of them are due to male reproductive disorders. Several previous studies demonstrated that PM2.5 particles has been consistently associated with critical human sperm reduction and impairment of human sperm chromatin and DNA from traffic exhaust pollution. Blood-testis barrier (BTB), a critically physical barrier between the seminiferous tubules and the blood vessels prevents sperm antigens from entering the blood circulation and facilitating and initiating an autoimmune response that contributing to spermatogenesis interference. Reactive oxygen species (ROS) are involved in the redox-sensitive signal transduction factors activation, such as Jun NH2-terminal kinase (JNK), p 38, extracellular signal-regulated kinase (ERK), and mitogen-activated protein kinases (MAPK) that critically influence BTB disruption. After PM2.5 exposure, there are decreased superoxide dismutase (SOD) expression, increased malondialdehyde (MDA) expression, increased nuclear factor erythroid 2-related factor 2 (Nrf-2) expression, increased expression of the four junctional proteins (β-catenin, Cx43, occludin, zonula occludens-1 (ZO-1)), thus improve sperm quality and quantity. PM2.5 particles markedly induce increasing phosphorylation of MAPKs via the ROS-mediated MAPK signaling pathway that causes BTB disruption, but this effect is lesser in the vitamins C and E intervention as well as increasing cleaved caspase-3 expression and the Bcl-2/Bax ratio. In conclusion, combined therapeutic administration of vitamins C and E can maintain the BTB integrity, reduce oxidative stress and cell apoptosis, and prevent toxic effects.

2-(4-methoxyphenylthio)-5,8-dimethoxy-1,4-naphthoquinone induces apoptosis via ROS-mediated MAPK and STAT3 signaling pathway in human gastric cancer cells

The 1,4-naphthoquinones and their derivatives have garnered great interest due to their antitumor pharmacological properties in various cancers; however, their clinical application is limited by side effects. In this study, to reduce side effects and improve therapeutic efficacy, a novel 1,4-naphthoquinone derivative—2-(4-methoxyphenylthio)-5,8-dimethoxy-1,4-naphthoquinone (MPTDMNQ) was synthesized. We investigated the effects and underlying mechanisms of MPTDMNQ on cell viability, apoptosis, and reactive oxygen species (ROS) generation in human gastric cancer cells. Our results showed that MPTDMNQ decreased cell viability in nine human gastric cancer cell lines. MPTDMNQ significantly induced apoptosis accompanied by the accumulation of ROS in GC cells. However, pre-treatment with the ROS scavenger N-acetyl-L-cysteine (NAC) attenuated the MPTDMNQ-induced apoptosis. Moreover, MPTDMNQ decreased the phosphorylation levels of extracellular signal-regulated kinase (ERK) and signal transducer and activator of transcription 3 (STAT3); and increased the phosphorylation levels of c-Jun N-terminal kinase (JNK) and p38 kinase. However, phosphorylation was inhibited by NAC and a mitogen-activated protein kinase (MAPK) inhibitor. These findings showed that MPTDMNQ induced AGS cell apoptosis via ROS-mediated MAPK and STAT3 signaling pathways. Thus, MPTDMNQ may be a promising candidate for treating gastric cancer.

Dietary soybean β‐conglycinin suppresses growth performance and inconsistently triggers apoptosis in the intestine of juvenile grass carp ( Ctenopharyngodon idella ) in association with ROS‐mediated MAPK signalling

The current study aimed to investigate the effects of dietary soybean beta-conglycinin on growth performance and intestine apoptosis in juvenile grass carp (Ctenopharyngodon idella). For fish fed with the 80 g beta-conglycinin/kg diet for 7 weeks, the specific growth rate and feed intake were decreased. In the proximal intestine, dietary beta-conglycinin did not induce DNA fragmentation, tended to decrease the reactive oxygen species (ROS) content, and decreased ROS-generating enzyme (NADPH oxidase [NOX]) activity. Subsequently, in the mid-intestine, dietary beta-conglycinin caused DNA fragmentation, tended to increase the ROS content, increased caspase-3, caspase-8 and caspase-9 activities, upregulated the mRNA levels of proapoptotic molecules (apoptotic protease-activating factor-1 [Apaf1] and Bcl-2-associated X protein [BAX]) and mitogen-activated protein kinase (MAPK)-related signal molecules (Jun N-terminal kinase (JNK) and p38 MAPK) and increased the protein levels of p38 MAPK and phospho-p38 MAPK. Moreover, in the distal intestine, dietary beta-conglycinin induced DNA fragmentation, elevated NOX activity and the ROS content and increased caspase-3, caspase-8 and caspase-9 activities, death ligand (TNF-alpha) mRNA expression level, and p38 MAPK and phospho-p38 MAPK protein levels. In summary, dietary soybean beta-conglycinin suppressed fish growth and inconsistently caused apoptosis among the different intestinal segments which was partially associated with ROS-mediated MAPK signalling.

New naphthalene derivatives induce human lung cancer A549 cell apoptosis via ROS-mediated MAPKs, Akt, and STAT3 signaling pathways

1,4-Naphthoquinone compounds are a class of organic compounds derived from naphthalene. They exert a wide variety of biological effects, but when used as anticancer drugs, have varying levels of side effects. In the present study, in order to reduce toxicity and improve the antitumor activity, we synthesized two novel 1,4-naphthoquinone derivatives, 2-(butane-1-sulfinyl)-1,4-naphthoquinone (BSQ) and 2-(octane-1-sulfinyl)-1,4-naphthoquinone (OSQ). We investigated the antitumor effects of BSQ and OSQ in human lung cancer cells and the underlying molecular mechanisms of these effects, focusing on the relationship between these compounds and reactive oxygen species (ROS) production. MTT assay and trypan blue exclusion assay results showed that BSQ and OSQ had significant cytotoxic effects in human lung cancer cells. Flow cytometry results indicated that the number of apoptotic cells and the intracellular ROS levels significantly increased after treatment with BSQ and OSQ. However, cell apoptosis was inhibited by pretreatment with the ROS scavenger N-acetyl-l-cysteine (NAC). Western blotting results showed that BSQ and OSQ increased the expression levels of p-p38 kinase and p-c-Jun N-terminal kinase (p-JNK), and decreased the expression levels of p-extracellular signal-regulated kinase (p-ERK), p-protein kinase B (p-Akt), and p-signal transducer and activator of transcription-3 (p-STAT3). These phenomena were blocked by mitogen-activated protein kinase (MAPK) inhibitors, Akt inhibitors and NAC. In conclusion, BSQ and OSQ induce human lung cancer A549 cell apoptosis by ROS-mediated MAPKs, Akt, and STAT3 signaling pathways. Therefore, BSQ and OSQ may be therapeutic potential agents for the treatment of human lung cancer.

Involvement of autophagy in hypoxia-BNIP3 signaling to promote epidermal keratinocyte migration

BNIP3 is an atypical BH3-only member of the Bcl-2 family with pro-death, pro-autophagic, and cytoprotective functions, depending on the type of stress and cellular context. Recently, we demonstrated that BNIP3 stimulates the migration of epidermal keratinocytes under hypoxia. In the present study found that autophagy and BNIP3 expression were concomitantly elevated in the migrating epidermis during wound healing in a hypoxia-dependent manner. Inhibition of autophagy through lysosome-specific chemicals (CQ and BafA1) or Atg5-targeted small-interfering RNAs greatly attenuated the hypoxia-induced cell migration, and knockdown of BNIP3 in keratinocytes significantly suppressed hypoxia-induced autophagy activation and cell migration, suggesting a positive role of BNIP3-induced autophagy in keratinocyte migration. Furthermore, these results indicated that the accumulation of reactive oxygen species (ROS) by hypoxia triggered the activation of p38 and JNK mitogen-activated protein kinase (MAPK) in human immortalized keratinocyte HaCaT cells. In turn, activated p38 and JNK MAPK mediated the activation of BNIP3-induced autophagy and the enhancement of keratinocyte migration. These data revealed a previously unknown mechanism that BNIP3-induced autophagy occurs through hypoxia-induced ROS-mediated p38 and JNK MAPK activation and supports the migration of epidermal keratinocytes during wound healing.

Mechanisms underlying isoliquiritigenin-induced apoptosis and cell cycle arrest via ROS-mediated MAPK/STAT3/NF-κB pathways in human hepatocellular carcinoma cells.

Isoliquiritigenin (ISL), a natural flavonoid isolated from plant licorice, has various pharmacological properties, including anticancer, anti-inflammatory, and antiviral effects. However, the underlying mechanisms and signaling pathways of ISL in human hepatocellular carcinoma (HCC) cells remain unknown. In this study, we evaluated the effects of ISL on the apoptosis of human HCC cells with a focus on reactive oxygen species (ROS) production. Our results showed that ISL exhibited cytotoxic effects on two human liver cancer cells in a dose-dependent manner. ISL significantly induced mitochondrial-related apoptosis and cell cycle arrest at the G2/M phase, which was accompanied by ROS accumulation in HepG2 cells. However, pretreatment with an ROS scavenger, N-acetyl-l-cysteine (NAC), inhibited ISL-induced apoptosis. In addition, ISL increased the phosphorylation levels of c-Jun N-terminal kinase (JNK), p38 kinase and inhibitor of NF-κB (IκB), and decreased the phosphorylation levels of extracellular signal-regulated kinase (ERK), signal transducer and activator of transcription 3 (STAT3), nuclear factor-kappa B (NF-κB), these effects were blocked by NAC and mitogen-activated protein kinase (MAPK) inhibitors. Taken together, the findings of this study indicate that ISL induced HepG2 cell apoptosis via ROS-mediated MAPK, STAT3, and NF-κB signaling pathways. Therefore, ISL may be a potential treatment for human HCC, as well as other cancer types.

Potent inhibition of gastric cancer cells by a natural compound via inhibiting TrxR1 activity and activating ROS-mediated p38 MAPK pathway

Thioredoxin reductase 1 (TrxR1) has emerged as a potential target for cancer therapy, because it is overexpressed in several types of cancers and associated with increased tumour growth and poor patient prognosis. Alantolactone (ALT), a natural sesquiterpene lactone originated from traditional folk medicine Inula helenium L., has been reported to exert antitumor activity in various tumours. However, the effect of ALT on human gastric cancer cells and its underlying mechanism remains unknown. In this study, we showed that ALT inhibited cell proliferation and induced cell apoptosis in gastric cancer cells. Mechanistically, our data found that ALT induced reactive oxygen species (ROS) production by inhibiting TrxR1 activity, resulting in the activation of p38 mitogen-activated protein kinase (MAPK) pathway and eventually cell apoptosis in gastric cancer cells. And the effects of ALT were reversed by pre-treatment with NAC (a scavenger of ROS). Further investigation revealed that ALT displayed synergistic lethality with erastin against gastric cancer cells, which demonstrating combined inhibition of TrxR1 and glutathione (GSH) leads to a synergistic effect in gastric cancer cells. More importantly, ALT treatment markedly reduced the activity of TrxR1 in vivo and inhibited the growth of gastric cancer xenografts without exhibiting significant toxicity. Taken together, these findings suggest that ALT may be used as a novel therapeutic agent against human gastric cancer.

Senkyunolide H protects against MPP+-induced apoptosis via the ROS-mediated mitogen-activated protein kinase pathway in PC12 cells

Senkyunolide H (SNH) is a phthalide isolated from the rhizome of Ligusticum chuanxiong Hort. that has been reported to have several pharmacological activities, including anti-atherosclerotic, antiproliferative, and cytoprotective effects. In this study, we investigated the neuroprotective effects and potential mechanisms of SNH against 1-methyl-4-phenylpyridinium (MPP+)-induced oxidative stress. We demonstrated that SNH pretreatment significantly attenuated MPP+-induced neurotoxicity and apoptosis in PC12 cells. In addition, SNH attenuated the effect of MPP+ on the expression of the pro-apoptotic factors Bax and caspase-3. Meanwhile, SNH prevented oxidative stress by reducing reactive oxygen species generation, mitochondrial membrane potential loss, cytochrome C release, and malondialdehyde levels while increasing antioxidant enzyme activity (e.g., superoxide dismutase, catalase, and glutathione peroxidase). In addition, SNH inhibited nuclear accumulation of nuclear factor-κB and c-Jun N-terminal kinase and phosphorylation p38 mitogen-activated protein kinases (MAPKs). Overall, this investigation provides novel evidence that SNH exerts neuroprotective effects via the ROS-mediated MAPK pathway and represents a potential preventive or therapeutic agent for neuronal disorders.

Hydrogen sulfide primes diabetic wound to close through inhibition of NETosis

Diabetes-induced neutrophil NETosis impairs wound healing through neutrophil extracellular traps (NETs). Reactive oxygen species (ROS)-triggered activation of mitogen-activated protein kinase (MAPK) ERK1/2 and p38 is involved in NETosis. Hydrogen sulfide (H2S), an endogenous signaling molecule, accelerates diabetic wound healing (DWH), and inhibits ROS production, ERK1/2 and p38 activation, while its level is decreased in diabetes. However, it remains unknown whether H2S could accelerate DWH through inhibition of NETosis, and whether this inhibitory effect was associated with blockage of ROS-induced ERK1/2 and p38 activation. In order to solve these problems, serum NETs content was measured in diabetic foot patients and healthy individuals. Wound was created in dorsal skin of LepRdb/db and control mice and NETs content in wound tissues was tested. An in vitro NETosis model was induced by phorbol 12-myristate 13-acetate (PMA) in isolated neutrophils. Effects of H2S in form of Na2S on skin wound healing and NETosis were investigated both in vivo and in vitro. It was found that NETs level was highly increased in diabetic foot patients. Comparing with LepRm+/db mice, DWH was delayed in LepRdb/db mice, accompanied with high NETs level. In PMA-induced NETosis model, peptidylarginine deiminase (PAD)-4 and citrullinated histone H3, as well as NETs components dsDNA framework, myeloperoxidase and neutrophil elastase, were significantly increased. PMA-induced neutrophil NETosis and NETs formation were abolished by treatment with H2S. The delayed DWH of diabetic mice was partially restored by intraperitoneal injection of H2S, meanwhile, the highly expressed NETosis and NETs release were also down-regulated. The treatment with H2S not only attenuated ROS production but also abolished MAPK ERK1/2 and p38 activation. Like the effects of H2S, inhibition of MAPK ERK1/2 or p38 could decrease NETs release. These findings suggests that H2S attenuates NETosis and primes diabetic wound to heal through blockage of ROS-mediated MAPK ERK1/2 and p38 activation.

Supplementation of American ginseng berry extract mitigated cisplatin-evoked nephrotoxicity by suppressing ROS-mediated activation of MAPK and NF-κB signaling pathways

Nephrotoxicity induced by cisplatin in 30% of all cisplatin treated patients seriously limits its clinical implication as a widely used anticancer agent, and may even cause patients to alter or give up cisplatin therapy. The purpose of this study is to test a protective effect of American ginseng berry extract (AGBE) on cisplatin-induced nephrotoxicity in mice. In this study, the histopathological changes and elevated levels of serum creatinine (CRE) and urea nitrogen (BUN) caused by cisplatin were significantly diminished by AGBE treatment. Oxidative stress caused by cisplatin, evidenced by increases in kidney tissues malondialdehyde (MDA) content, cytochrome P450 E1 (CYP2E1), renal 4-hydroxynonenal (4-HNE) levels and decreases of glutathione (GSH) and superoxide dismutase (SOD) contents, was significantly ameliorated by AGBE pretreatment. The expression levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) were inhibited by AGBE treatment, suggesting a suppression of inflammatory response. Additionally, AGBE clearly inhibited cisplatin-induced activations of nuclear factor-kappa B (NF-κB) and mitogen activated protein kinase (MAPK) signal pathways. Supplementation of cisplatin-intoxicated mice with AGBE also significantly reduced apoptotic protein levels of Bax, cleaved caspase-3, cytochrome c and increased anti-apoptotic protein Bcl-2. These findings highlight nephroprotective effect of AGBE against cisplatin-evoked nephrotoxicity through ROS-mediated MAPK and NF-κB signaling pathways.

3, 4-dihydroxybenzalacetone attenuates lipopolysaccharide-induced inflammation in acute lung injury via down-regulation of MMP-2 and MMP-9 activities through suppressing ROS-mediated MAPK and PI3K/AKT signaling pathways

3, 4-Dihydroxybenzalacetone (DBL) is a constituent of Phellinus linteus. This study demonstrated the protective effect of DBL on lipopolysaccharide (LPS)–induced acute lung injuries in mice.Pretreatment with DBL significantly improved LPS–induced histological alterations in lung tissues. In addition, DBL markedly reduced the total cell number, the leukocytes, the protein concentrations, and decreased the release of nitrite, tumor necrosis factor (TNF)–α, interleukin (IL)–1β, IL–6 and the activities of matrix metalloproteinase (MMP)–2 and –9 in the bronchoalveolar lavage fluid. DBL also inhibited the W/D ratio and myeloperoxidase activity in the lung tissues. Western blot analysis indicated DBL efficiently blocked the protein expressions of inducible nitric oxide synthase, cyclooxygenase–2, MMP–2, MMP–9, and the phosphorylation of mitogen–activated protein kinase (MAPK), phosphoinositide–3–kinase (PI3K), AKT, Toll–like receptor 4 (TLR4) and nuclear factor (NF)–κB. Moreover, DBL enhanced the expression of anti–oxidant proteins, such as superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx). Based on our results, DBL might be a potential target for attenuating tissue oxidative injuries and nonspecific pulmonary inflammation.

BNIP3 upregulation via stimulation of ERK and JNK activity is required for the protection of keratinocytes from UVB-induced apoptosis

The human skin has an important role in barrier function. Ultraviolet rays (UV) from sunlight exposure can cause cell apoptosis in the skin epidermis, resulting in the disruption of the barrier. Previously, we have demonstrated that BNIP3 stimulates autophagy in epidermal keratinocytes and has a protective effect in these cells upon UVB irradiation. In this study, we found that the accumulation of reactive oxygen species (ROS) by UVB irradiation was sufficient to trigger the activation of JNK and ERK mitogen-activated protein kinase (MAPK) in human primary epidermal keratinocytes. In turn, activated JNK and ERK MAPK mediated the upregulation of BNIP3 expression. Treatment with an antioxidant reagent or a specific inhibitor of MAPK, U0126, and a JNK inhibitor significantly attenuated the expression of BNIP3 triggered by UVB, followed by the induction of cell death by apoptosis. Furthermore, UVB-induced apoptosis was significantly stimulated by chloroquine or bafilomycin A1, an inhibitor of autophagy. Moreover, BNIP3 was required for the degradation of dysfunctional mitochondria upon UVB irradiation. These data clearly indicated that BNIP3-induced autophagy, which occurs via UVB-generated ROS-mediated JNK and ERK MAPK activation, has a crucial role in the protection of the skin epidermis against UVB irradiation.