2-(Naphthalene-2-thio)-5,8-dimethoxy-1,4-naphthoquinone induces apoptosis via ROS-mediated MAPK, AKT, and STAT3 signaling pathways in HepG2 human hepatocellular carcinoma cells.

1,4-naphthoquinone and its derivatives have attracted widespread attention due to their multiple biological activities, such as induction of cancer cell apoptosis; however, most of these compounds have high cytotoxicity. In this study, in order to reduce their toxicity and increase their potential anti-tumor effects, we synthesized a novel 1,4-naphthoquinone derivative named 2-(naphthalene-2-thio)-5,8-dimethoxy-1,4-naphthoquinone (NTDMNQ), and investigated its apoptotic effects and underlying mechanism. Our results showed that NTDMNQ inhibited the viability of HepG2, Hep3B, and Huh7 human hepatocellular carcinoma (HCC) cells. It also increased the accumulation of cells in the G0/G1 phase of the cell cycle by increasing the expression levels of p-p53, p21 and p27, while decreasing the levels of Cyclin D1, Cyclin E, Cyclin-dependent kinase 2 (CDK2), CDK4, and CDK6. Inhibition of reactive oxygen species (ROS) by the ROS scavenger N-acetyl-L-cysteine (NAC) decreased apoptosis in NTDMNQ-treated cells. Western blot analysis showed that NTDMNQ increased the phosphorylation of p38 and c-Jun N-terminal kinase (JNK), and decreased the phosphorylation of extracellular signal-regulated kinase (ERK), AKT, and signal transducer and activator of transcription-3 (STAT3); these effects were blocked by NAC. Both the JNK inhibitor (SP600125) and p38 inhibitor (SB203580) reversed the phosphorylation of STAT3, and the ERK inhibitor (FR180204) and AKT inhibitor (LY294002) reduced the expression of STAT3. Taken together, these findings suggest that NTDMNQ induces apoptosis via ROS-mediated MAPK, AKT and STAT3 signaling pathways in HepG2 cells, and may be a potent anticancer agent.

2-(6-Hydroxyhexylthio)-5,8-dimethoxy-1,4-naphthoquinone Induces Apoptosis through ROS-Mediated MAPK, STAT3, and NF-κB Signalling Pathways in Lung Cancer A549 Cells.

Two novel compounds, 2-(2-hydroxyethylthio)-5,8-dimethoxy-1,4-naphthoquinone (HEDMNQ) and 2-(6-hydroxyhexylthio)-5,8-dimethoxy-1,4-naphthoquinone (HHDMNQ), were synthesized to investigate the kill effects and mechanism of 1,4-naphthoquinone derivatives in lung cancer cells. The results of the CCK-8 assay showed that HEDMNQ and HHDMNQ had significant cytotoxic effects on A549, NCI-H23, and NCI-H460 NSCLC cells. Flow cytometry and western blot results indicated that HHDMNQ induced A549 cell cycle arrest at the G2/M phase by decreasing the expression levels of cyclin-dependent kinase 1/2 and cyclin B1. Fluorescence microscopy and flow cytometry results indicated that HHDMNQ could induce A549 cell apoptosis, and western blot analysis showed that HHDMNQ induced apoptosis through regulating the mitochondria pathway, as well as the MAPK, STAT3, and NF-κB signalling pathways. Flow cytometry results showed that intracellular reactive oxygen species (ROS) levels were increased after HHDMNQ treatment, and western blot showed that ROS could modulate the intrinsic pathway and MAPK, STAT3, and NF-κB signalling pathways. These effects were blocked by the ROS inhibitor N-acetyl-L-cysteine in A549 cells. Our findings suggest that compared with HEDMNQ, HHDMNQ had the stronger ability to inhibit the cell viability of lung cancer cells and induce apoptosis by regulating the ROS-mediated intrinsic pathway and MAPK/STAT3/NF-κB signalling pathways. Thus, HHDMNQ might be a potential antitumour compound for treating lung cancer.

DNA Nanofirecrackers Assembled through Hybridization Chain Reaction for Ultrasensitive SERS Immunoassay of Prostate Specific Antigen.

Isothermal nucleic acid amplification technology has been widely adopted for analytical chemistry with the purpose of sensitivity improvement. Herein we present an ultrasensitive concatenated hybridization chain reaction (C-HCR) based surface-enhanced Raman scattering (SERS) immunoassay by forming antibody-antigen-aptamer heterosandwich structures with the model analyte of total prostate specific antigens (tPSA). In the C-HCR, two HCRs, one proceeds with two hairpins and the other with four biotin-modified hairpins, are coupled, making the formation of DNA nanofirecrackers with the lengths longer than 200 nm and more than four hundred million binding sites of streptavidin modified enzymes. These types of DNA nanofirecrackers through the aptamer encoded linker strand to form heterosandwich structures could provide a general signal application platform such as enzyme catalysis with high amplification efficiency. As a proof of concept, the Au@Ag core-shell nanostructure based SERS immunoassay with excellent signal amplification has been developed by employing the streptavidin modified alkaline phosphatase (SA-ALP) through its catalysis of 2-phospho-l-ascorbic acid trisodium salt (AAP) to form Au@Ag core-shell nanostructures via the formation of ascorbic acid (AA) to reduce AgNO3 and deposition of silver element on gold nanorods (AuNRs). The newly developed method has a detection limit as low as 0.94 fg/mL and has successfully achieved the detection of serum samples from clinical patients, which was consistent with the clinical test results, showing that this C-HCR strategy to form DNA nanofirecrackers has great potential in clinical applications.

Nanofabrication of hollowed-out Au@AgPt core-frames via selective carving of silver and deposition of platinum.

Here, a hollowed-out Au@AgPt core-frame nanostructure is carved in the presence of PtCl62-via galvanic replacement (GR) reaction, during which the dissolution of Ag atoms from the {100} facets and the deposition of Pt atoms on the active edges of the nanocubes occur. Both ex situ and in situ monitoring of the plasmonic and structural evolutions at the single-particle level, confirmed also by theoretical simulations, shows a three-phase mechanism involved.

Liquiritin inhibits proliferation and induces apoptosis in HepG2 hepatocellular carcinoma cells via the ROS-mediated MAPK/AKT/NF-κB signaling pathway.

Liquiritin (LIQ), a major constituent of Glycyrrhiza Radix, exhibits various pharmacological activities. In this study, to explore the potential anti-cancer effects and its underlying molecular mechanisms of LIQ in hepatocellular carcinoma (HCC) cells. LIQ significantly decreased viability and induced apoptosis in HepG2 cells by decreasing mitochondrial membrane potential and regulating Bcl-2 family proteins, cytochrome c, cle-caspase-3, and cle-PARP. The cell cycle analysis and western blot analysis revealed that LIQ induced G2/M phase arrest through increased expression of p21 and decreased levels of p27, cyclin B, and CDK1/2. The flow cytometry and western blot analysis also suggested that LIQ promoted the accumulation of ROS in HepG2 cells and up-regulated the phosphorylation expression levels of p38 kinase, c-Jun N-terminal kinase (JNK), and inhibitor of NF-κB (IκB-α); the phosphorylation levels of extracellular signal-regulated kinase (ERK), protein kinase B (AKT), signal transducer activator of transcription 3 (STAT3), and nuclear factor kappa B (NF-κB) were down-regulated. However, these effects were reversed by N-acetyl-L-cysteine (NAC), MAPK, and AKT inhibitors. The findings demonstrated that LIQ induced cell cycle arrest and apoptosis via the ROS-mediated MAPK/AKT/NF-κB signaling pathway in HepG2 cells, and the LIQ may serve as a potential therapeutic agent for the treatment of human HCC.

Cytisine exerts anti-tumour effects on lung cancer cells by modulating reactive oxygen species-mediated signalling pathways.

Cytisine is a natural product isolated from plants and is a member of the quinolizidine alkaloid family. This study aims to investigate the effect of cytisine in human lung cancer. Cell viability was determined using the CCK-8 assay, and the results showed that cytisine inhibited the growth of lung cancer cell lines. The apoptotic effects were evaluated using flow cytometry, and the results showed that cytisine induced mitochondrial-dependent apoptosis through loss of the mitochondrial membrane potential; increased expression of BAD, cleaved caspase-3, and cleaved-PARP; and decreased expression levels of Bcl-2, pro-caspase-3, and pro-PARP. In addition, cytisine caused G2/M phase cell cycle arrest that was associated with inhibiting the AKT signalling pathway. During apoptosis, cytisine increased the phosphorylation levels of JNK, p38, and I-κB, and decreased the phosphorylation levels of ERK, STAT3, and NF-κB. Furthermore, cytisine treatment led to the generation of ROS, and the NAC attenuated cytisine-induced apoptosis. In vivo, cytisine administration significantly inhibited the lung cancer cell xenograft tumorigenesis. In conclusion, cytisine plays a critical role in suppressing the carcinogenesis of lung cancer cells through cell cycle arrest and induction of mitochondria-mediated apoptosis, suggesting that it may be a promising candidate for the treatment of human lung cancer.

Quinalizarin induces ROS­mediated apoptosis via the MAPK, STAT3 and NF­κB signaling pathways in human breast cancer cells.

Quinalizarin has been demonstrated to exhibit potent antitumor activities in lung cancer and gastric cancer cells, but currently, little is known regarding its anticancer mechanisms in human breast cancer cells. The aim of the present study was to investigate the apoptotic effects of quinalizarin in MCF­7 cells and to analyze its molecular mechanisms. The MTT assay was used to evaluate the viability of human breast cancer cells that had been treated with quinalizarin and 5­fluorouracil. Flow cytometric analyses and western blotting were used to investigate the effects of quinalizarin on apoptosis and cycle arrest in MCF­7 cells with focus on reactive oxygen species (ROS) production. The results demonstrated that quinalizarin exhibited significant cytotoxic effects on human breast cancer cells in a dose­dependent manner. Accompanying ROS, quinalizarin induced MCF­7 cell mitochondrial­associated apoptosis by regulating mitochondrial­associated apoptosis, and caused cell cycle arrest at the G2/M phase in a time­dependent manner. Furthermore, quinalizarin can activate p38 kinase and JNK, and inhibit the extracellular signal­regulated kinase, signal transducer and activator of transcription 3 (STAT3) and NF­κB signaling pathways. These effects were blocked by mitogen­activated protein kinase (MAPK) inhibitor and N­acetyl­L­cysteine. The results from the present study suggested that quinalizarin induced G2/M phase cell cycle arrest and apoptosis in MCF­7 cells through ROS­mediated MAPK, STAT3 and NF­κB signaling pathways. Thus, quinalizarin may be useful for human breast cancer treatment, as well as the treatment of other cancer types.

Quinalizarin induces cycle arrest and apoptosis via reactive oxygen species-mediated signaling pathways in human melanoma A375 cells.

Quinalizarin, a bioactive and highly selective compound, is known to promote apoptosis in colon and lung cancer cells. However, studies evaluating quinalizarin-induced apoptosis in melanoma cells have not been conducted. In the present study, we investigated the underlying mechanisms of antimelanoma activity of quinalizarin in human melanoma A375 cells. The MTT assay and Trypan blue staining were used to evaluate the cell viability. The flow cytometry was used to detect cell cycle, apoptosis and reactive oxygen species (ROS). Western blot was used to detect the expression of cell cycle and apoptosis-related proteins, MAPK, and STAT3. The results revealed a significant dose and time dependent effect of quinalizarin on inhibiting proliferation in three kinds of human melanoma cells, and had no significant toxic effects on normal cells. Moreover, quinalizarin triggered G2/M phase cell arrest by modulating the protein expression levels of CDK 1/2, cyclin A, cyclin B, p21 and p27, and induced apoptosis by down-regulating the antiapoptotic protein Bcl-2 and upregulating the proapoptotic protein BAD, leading to the activation of caspase-3 and PARP in the caspase cascade in A375 cells. Quinalizarin treatment led to apoptosis of A375 cells via activation of MAPK and inhibition of STAT3 signaling pathways. In addition, quinalizarin increased the level of ROS, but ROS scavenger NAC inhibited quinalizarin-induced apoptosis by regulating MAPK and STAT3 signaling pathways. In summary, quinalizarin induces cell cycle arrest and apoptosis via ROS-mediated MAPK and STAT3 signaling pathways in human melanoma A375 cells, and quinalizarin may be used as a novel and effective antimelanoma therapeutic.

Two novel 1,4­naphthoquinone derivatives induce human gastric cancer cell apoptosis and cell cycle arrest by regulating reactive oxygen species­mediated MAPK/Akt/STAT3 signaling pathways.

1,4­Naphthoquinone derivatives have superior anticancer effects, but their use has been severely limited in clinical practice due to adverse side effects. To reduce the side effects and extend the anticancer effects of 1,4­naphthoquinone derivatives, 2­(butane­1­sulfinyl)­1,4­naphthoquinone (BQ) and 2­(octane­1­sulfinyl)­1,4­naphthoquinone (OQ) were synthesized, and their anticancer activities were investigated. The anti­proliferation effects, determined by MTT assays, showed that BQ and OQ significantly inhibited the viability of gastric cancer cells and had no significant cytotoxic effect on normal cell lines. The apoptotic effect was determined by flow cytometry, and the results showed that BQ and OQ induced cell apoptosis by regulating the mitochondrial pathway and cell cycle arrest at the G2/M phase via inhibition of the Akt signaling pathway in AGS cells. Furthermore, BQ and OQ significantly increased the levels of reactive oxygen species (ROS) and this effect was blocked by the ROS scavenger NAC in AGS cells. BQ and OQ induced apoptosis by upregulating the protein expression of p38 and JNK and downregulating the levels of ERK and STAT3. Furthermore, expression levels of these proteins were also blocked after NAC treatment. These results demonstrated that BQ and OQ induced apoptosis and cell cycle arrest at the G2/M phase in AGS cells by stimulating ROS generation, which caused subsequent activation of MAPK, Akt and STAT3 signaling pathways. Thus, BQ and OQ may serve as potential therapeutic agents for the treatment of human gastric cancer.

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.

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.

The design of 1,4-naphthoquinone derivatives and mechanisms underlying apoptosis induction through ROS-dependent MAPK/Akt/STAT3 pathways in human lung cancer cells.

The natural compound 1,4-naphthoquinone has potent anti-tumor activity. However, the clinical application of 1,4-naphthoquinone and its derivatives has been limited by their side effects. In this study, we attempted to reduce the toxicity of 1,4-naphthoquinone by synthesizing two derivatives: 2,3-dihydro-2,3-epoxy-2-propylsulfonyl-5,8-dimethoxy-1,4-naphthoquinone (EPDMNQ) and 2,3-dihydro-2,3-epoxy-2-nonylsulfonyl-5,8-dimethoxy-1,4-naphthoquinone (ENDMNQ). Then we evaluated the cytotoxicity and molecular mechanisms of these compounds in lung cancer cells. EPDMNQ and ENDMNQ significantly inhibited the viabilities of three lung cancer cell lines and induced A549 cell cycle arrest at the G1 phase. In addition, they induced the apoptosis of A549 lung cancer cells by increasing the phosphorylation of p38 and c-Jun N-terminal kinase (p-JNK), and decreasing the phosphorylation of extracellular signal-related kinase (p-ERK), protein kinase B (Akt), and signal transducer and activator of transcription 3 (STAT3). Furthermore, they increased reactive oxygen species (ROS) levels in A549 cells; however, pretreatment with the ROS inhibitor N-acetyl-l-cysteine significantly inhibited EPDMNQ- and ENDMNQ-mediated apoptosis and reversed apoptotic proteins expression. In conclusion, EPDMNQ and ENDMNQ induced G1 phase cell cycle arrest and apoptosis in A549 cells via the ROS-mediated activation of mitogen activated protein kinase (MAPK), Akt and STAT3 signaling pathways.

Glycitein induces reactive oxygen species-dependent apoptosis and G0/G1 cell cycle arrest through the MAPK/STAT3/NF-κB pathway in human gastric cancer cells.

Glycitein is an isoflavone that reportedly inhibits the proliferation of human breast cancer and prostate cancer cells. However, its anti-cancer molecular mechanisms in human gastric cancer remain to be defined. This study evaluated the antitumor effects of glycitein on human gastric cancer cells and investigated the underlying mechanisms. We used MTT assay, flow cytometry and western blotting to investigate its molecular mechanisms with focus on reactive oxygen species (ROS) production. Our results showed that glycitein had significant cytotoxic effects on human gastric cancer cells. Glycitein markedly decreased mitochondrial transmembrane potential (ΔΨm) and increased AGS cells mitochondrial-related apoptosis, and caused G0/G1 cell cycle arrest by regulating cycle-related protein. Mechanistically, accompanying ROS, glycitein can activate mitogen-activated protein kinase (MAPK) and inhibited the signal transducer and activator of transcription 3 (STAT3) and nuclear factor-kappaB (NF-κB) signaling pathways. Furthermore, the MAPK signaling pathway regulated the expression levels of STAT3 and NF-κB upon treatment with MAPK inhibitor and N-acetyl-L-cysteine (NAC). These findings suggested that glycitein induced AGS cell apoptosis and G0/G1 phase cell cycle arrest via ROS-related MAPK/STAT3/NF-κB signaling pathways. Thus, glycitein has the potential to a novel targeted therapeutic agent for human gastric cancer.

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.

Cryptotanshinone induces reactive oxygen species­mediated apoptosis in human rheumatoid arthritis fibroblast­like synoviocytes.

The present study investigated the mechanisms of apoptosis induced by cryptotanshinone (CT) in human rheumatoid arthritis fibroblast­like synoviocytes (RA­FLSs). Cell Counting kit­8 assay was performed to determine the cytotoxic effects of CT in human RA­FLSs, including primary RA­FLS, HFLS­RA and MH7A cells, and in HFLS cells derived from normal synovial tissue. Annexin V­FITC/PI staining was used to detect the apoptotic effects of CT in HFLS­RA and MH7A cells. Flow cytometry was performed to detect the apoptotic and reactive oxygen species (ROS) levels induced by CT in HFLS­RA cells. Western blotting was used to assess the expression levels of proteins associated with apoptosis and with the mitogen­activated protein kinase (MAPK), protein kinase B (Akt), and signal transducer and activator of transcription­3 (STAT3) signaling pathways. The results demonstrated that CT treatment significantly suppressed HFLS­RA and MH7A cell growth, whereas no clear inhibitory effect was observed in normal HFLS cells. CT exposure downregulated the expression levels of B­cell lymphoma 2 (Bcl­2), p­Akt, p­extracellular signal­related kinase and p­STAT3, while it upregulated the expression levels of Bcl­2­associated death promoter (Bad), caspase­3, poly (ADP­ribose) polymerase (PARP), p­p38 and p­c­Jun N­terminal kinase. Following ROS scavenging, the CT­induced apoptosis and altered expression levels of Bcl­2, Bad, cleaved caspase­3 and cleaved PARP were restored. Furthermore, the Akt, MAPK and STAT3 signaling pathways were regulated by intracellular ROS. These results suggest that ROS­mediated Akt, MAPK and STAT3 signaling pathways serve important roles in the CT­induced apoptosis of RA­FLSs.

Novel 1,4­naphthoquinone derivatives induce reactive oxygen species­mediated apoptosis in liver cancer cells.

Derivatives of 1,4­naphthoquinone have excellent anti­cancer effects, but their use has been greatly limited due to their serious side effects. To develop compounds with decreased side effects and improved anti­cancer activity, two novel types of 1,4­naphthoquinone derivatives, 2,3­dihydro­2,3­epoxy­2­propylsulfonyl­5,8­dimethoxy­1,4­naphthoquinone (EPDMNQ) and 2,3­dihydro­2,3­epoxy­2­nonylsulfonyl­5,8­dimethoxy­1,4­naphthoquinone (ENDMNQ) were synthesized and their anti­tumor activities were investigated. The effects of EPDMNQ and ENDMNQ on cell viability, apoptosis and accumulation of reactive oxygen species (ROS) in liver cancer cells were determined by MTT cell viability assay and flow cytometry. The expression levels of mitochondrial, mitogen activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) signaling pathway­associated proteins in Hep3B liver cancer cells were analyzed by western blot analysis. The results demonstrated that EPDMNQ and ENDMNQ inhibited the proliferation of liver cancer Hep3B, HepG2, and Huh7 cell lines but not that of normal liver L­02, normal lung IMR­90 and stomach GES­1 cell lines. The number of apoptotic cells and ROS levels were significantly increased following treatment with EPDMNQ and ENDMNQ, and these effects were blocked by the ROS inhibitor N­acetyl­L­cysteine (NAC) in Hep3B cells. EPDMNQ and ENDMNQ induced apoptosis by upregulating the protein expression of p38 MAPK and c­Jun N­terminal kinase and downregulating extracellular signal­regulated kinase and STAT3; these effects were inhibited by NAC. The results of the present study demonstrated that EPDMNQ and ENDMNQ induced apoptosis through ROS­modulated MAPK and STAT3 signaling pathways in Hep3B cells. Therefore, these novel 1,4­naphthoquinone derivatives may be useful as anticancer agents for the treatment of liver cancer.

The compound 2-(naphthalene-2-thio)-5,8-dimethoxy-1,4-naphthoquinone induces apoptosis via reactive oxygen species-regulated mitogen-activated protein kinase, protein kinase B, and signal transducer and activator of transcription 3 signaling in human gastric cancer cells.

Hit, Lead & Candidate Discovery It is reported that 1,4-naphthoquinones and their derivatives have potent antitumor activity in various cancers, although their clinical application is limited by observed side effects. To improve the therapeutic efficacy of naphthoquinones in the treatment of cancer and to reduce side effects, we synthesized a novel naphthoquinone derivative, 2-(naphthalene-2-thio)-5,8-dimethoxy-1,4-naphthoquinone (NTDMNQ). In this study, we explored the effects of NTDMNQ on apoptosis in gastric cancer cells with a focus on reactive oxygen species (ROS) production. Our results demonstrated that NTDMNQ exhibited the cytotoxic effects on gastric cancer cells in a dose-dependent manner. NTDMNQ significantly induced mitochondrial-related apoptosis in AGS cells and increased the accumulation of ROS. However, pre-treatment with N-acetyl-L-cysteine (NAC), an ROS scavenger, inhibited the NTDMNQ-induced apoptosis. In addition, NTDMNQ increased the phosphorylation of p38 kinase and c-Jun N-terminal kinase (JNK) and decreased the phosphorylation of extracellular signal-regulated kinase (ERK), protein kinase B (Akt), and Signal Transducer and Activator of Transcription 3 (STAT3); these effects were blocked by mitogen-activated protein kinase (MAPK) inhibitor and NAC. Taken together, the present findings indicate that NTDMNQ-induced gastric cancer cell apoptosis via ROS-mediated regulation of the MAPK, Akt, and STAT3 signaling pathways. Therefore, NTDMNQ may be a potential treatment for gastric cancer as well as other tumor types.

Quinalizarin Induces Apoptosis through Reactive Oxygen Species (ROS)-Mediated Mitogen-Activated Protein Kinase (MAPK) and Signal Transducer and Activator of Transcription 3 (STAT3) Signaling Pathways in Colorectal Cancer Cells.

BACKGROUND Quinalizarin (1,2,5,8-tetrahydroxyanthraquinone) exhibits potentially useful anticancer effects by inducing apoptosis in several types of cancer, but its underlying mechanism of action remains unknown. The present study examined the effects of quinalizarin on the induction of cell cycle arrest, apoptosis, the generation of reactive oxygen species (ROS), other underlying mechanisms, and its role in modifying colorectal cancer cell lines. MATERIAL AND METHODS The MTT assay was used to evaluate the viability of SW480 and HCT-116 cells that had been treated with quinalizarin and 5-fluorouracil (5-FU). Cell cycle arrest and apoptosis were analyzed by flow cytometry. Western blotting was used to investigate the mitochondrial pathway; Akt, MAPK, and STAT3 signaling pathways were also investigated. The relationship between ROS generation and apoptosis was analyzed by flow cytometry and western blotting. RESULTS The results indicated that quinalizarin significantly inhibits the viability of SW480 and HCT-116 cells in a dose-dependent manner. Quinalizarin induced SW480 cell cycle arrest at G2/M by regulating cyclin B1 and CDK1/2. The apoptosis-related protein expression levels of p-p53, Bad, cleaved caspase-3, cleaved PARP and p-JNK were increased in quinalizarin-treated cells, while protein expression levels Bcl-2, p-Akt, p-ERK, and p-STAT3 were decreased. Quinalizarin induced apoptosis in colorectal cancer cells by regulating MAPK and STAT3 signaling pathways via ROS generation. CONCLUSIONS Quinalizarin induces apoptosis via ROS-mediated MAPK/STAT3 signaling pathways.

Novel 1,4-naphthoquinone derivatives induce apoptosis via ROS-mediated p38/MAPK, Akt and STAT3 signaling in human hepatoma Hep3B cells.

1,4-Naphthoquinone and its derivatives have shown some efficacy as therapeutic compounds for cancer and inflammation, though their clinical application is limited by their side-effects. To reduce the toxicity of these compounds and optimize their effects, we synthesized two 1,4-naphthoquinone derivatives-2-butylsulfinyl- 1,4-naphthoquinone (BSNQ) and 2-octylsulfinyl-1,4-naphthoquinone (OSNQ)-and investigated their effects and underlying mechanisms in hepatocellular carcinoma cells. BSNQ and OSNQ decreased cell viability and significantly induced apoptosis, accompanied by the accumulation of reactive oxygen species (ROS). However, pretreatment with N-acetyl-l-cysteine, a specific ROS scavenger, blocked apoptosis. Western blot results indicated that BSNQ and OSNQ up-regulated the phosphorylation of p38 and JNK, and down-regulated the phosphorylation of ERK, Akt and STAT3, and that these effects were blocked by N-acetyl-l-cysteine. Furthermore, BSNQ and OSNQ suppressed tumor growth and modulated MAPK and STAT3 signaling in mouse xenografts without detectable effects on body weight or hematological parameters. These results indicate that BSNQ and OSNQ induce apoptosis in human hepatoma Hep3B cells via ROS-mediated p38/MAPK, Akt and STAT3 signaling pathways, suggesting that these 1,4-naphthoquinone derivatives may provide promising new anticancer agents to treat HCC.

Quinalizarin exerts an anti-tumour effect on lung cancer A549 cells by modulating the Akt, MAPK, STAT3 and p53 signalling pathways.

Quinalizarin may be a potential chemical agent for cancer therapy, as it exerts anti­tumour effects against a variety of different types of cancer. However, the underlying regulatory mechanism and signalling pathways of quinalizarin in lung cancer cells remains unknown. The present study sought to investigate the effects of quinalizarin on proliferation, apoptosis and reactive oxygen species (ROS) generation in lung cancer. MTT assays were used to evaluate the effects of quinalizarin on the viability of lung cancer A549, NCI­H460 and NCI­H23 cells. Flow cytometry was employed to evaluate the effects of quinalizarin on the cell cycle, apoptosis and ROS generation in A549 cells. Western blotting was performed to detect cell cycle and apoptosis­associated protein expression levels in A549 cells. Quinalizarin inhibited A549, NCI­H460 and NCI­H23 cell proliferation and induced A549 cell cycle arrest at the G0/G1 phase. Quinalizarin induced apoptosis by upregulating the expression of B­cell lymphoma 2 (Bcl­2)­associated agonist of cell death, cleaved­caspase­3 and cleaved­poly (adenosine diphosphate­ribose) polymerase, and downregulating the expression of Bcl­2. Furthermore, quinalizarin activated mitogen­activated protein kinase (MAPK) and p53, and inhibited the protein kinase B and signal transducer and activator of transcription­3 (STAT3) signalling pathways. In addition, quinalizarin increased ROS generation. The ROS scavenger N­acetyl­L­cysteine restored quinalizarin­induced cell apoptosis, and inactivated the MAPK and STAT3 signalling pathways. The results of the present study demonstrated that quinalizarin induces G0/G1 phase cell cycle arrest and apoptosis via ROS mediated­MAPK and STAT3 signalling pathways.