Mitochondrial targeting sequence of magnetoreceptor MagR: More than just targeting.

Iron-sulfur clusters are essential cofactors for proteins involved in various biological processes, such as electron transport, biosynthetic reactions, DNA repair, and gene expression regulation. Iron-sulfur cluster assembly protein IscA1 (or MagR) is found within the mitochondria of most eukaryotes. Magnetoreceptor (MagR) is a highly conserved A-type iron and iron-sulfur cluster-binding protein, characterized by two distinct types of iron-sulfur clusters, [2Fe-2S] and [3Fe-4S], each conferring unique magnetic properties. MagR forms a rod-like polymer structure in complex with photoreceptive cryptochrome (Cry) and serves as a putative magnetoreceptor for retrieving geomagnetic information in animal navigation. Although the N-terminal sequences of MagR vary among species, their specific function remains unknown. In the present study, we found that the N-terminal sequences of pigeon MagR, previously thought to serve as a mitochondrial targeting signal (MTS), were not cleaved following mitochondrial entry but instead modulated the efficiency with which iron-sulfur clusters and irons are bound. Moreover, the N-terminal region of MagR was required for the formation of a stable MagR/Cry complex. Thus, the N-terminal sequences in pigeon MagR fulfil more important functional roles than just mitochondrial targeting. These results further extend our understanding of the function of MagR and provide new insights into the origin of magnetoreception from an evolutionary perspective.

FAM111B Acts as an Oncogene in Bladder Cancer.

Bladder cancer (BLCA) is a prevalent malignancy of the urinary system, associated with a high recurrence rate and poor prognosis. FAM111B, which encodes a protein containing a trypsin-like cysteine/serine peptidase domain, has been implicated in the progression of various human cancers; however, its involvement in BLCA remains unclear. In this study, we investigated the expression of FAM111B gene in tumor tissues compared to para-tumor tissues using immunohistochemistry and observed a significantly higher FAM111B gene expression in tumor tissues. Furthermore, analysis of clinical characteristics indicated that the increased FAM111B gene expression correlated with lymphatic metastasis and reduced overall survival. To investigate its functional role, we employed FAM111B-knockdown BLCA cell models and performed cell proliferation, wound-healing, transwell, and flow cytometry assays. The results showed that decreased FAM111B gene expression inhibited proliferation and migration but induced apoptosis in BLCA cells. In vivo experiments further validated that FAM111B knockdown suppressed tumor growth. Overall, our findings suggest that FAM111B acts as an oncogene in BLCA, playing a critical role in tumorigenesis, progression, and metastasis of BLCA. In conclusion, we have demonstrated a strong correlation between the expression of FAM111B gene and the development, progression, and metastasis of bladder cancer (BLCA). Thus, FAM111B is an oncogene associated with BLCA and holds promise as a molecular target for future treatment of this cancer.

Dissecting the intricacies of human antibody responses to SARS-CoV-1 and SARS-CoV-2 infection.

The 2003 severe acute respiratory syndrome coronavirus (SARS-CoV-1) causes more severe disease than SARS-CoV-2, which is responsible for COVID-19. However, our understanding of antibody response to SARS-CoV-1 infection remains incomplete. Herein, we studied the antibody responses in 25 SARS-CoV-1 convalescent patients. Plasma neutralization was higher and lasted longer in SARS-CoV-1 patients than in severe SARS-CoV-2 patients. Among 77 monoclonal antibodies (mAbs) isolated, 60 targeted the receptor-binding domain (RBD) and formed 7 groups (RBD-1 to RBD-7) based on their distinct binding and structural profiles. Notably, RBD-7 antibodies bound to a unique RBD region interfaced with the N-terminal domain of the neighboring protomer (NTD proximal) and were more prevalent in SARS-CoV-1 patients. Broadly neutralizing antibodies for SARS-CoV-1, SARS-CoV-2, and bat and pangolin coronaviruses were also identified. These results provide further insights into the antibody response to SARS-CoV-1 and inform the design of more effective strategies against diverse human and animal coronaviruses.

Infection and transovarial transmission of severe fever with thrombocytopenia syndrome virus in Rhipicephalus sanguineus in Hainan Island, China.

Severe fever with thrombocytopenia syndrome virus (SFTSV) RNA level increased in female ticks after injection with SFTSV. Furthermore, SFTSV RNA was detected in the eggs and larvae that originated from the virus-infected female ticks.

NLRC5 restricts dengue virus infection by promoting the autophagic degradation of viral NS3 through E3 ligase CUL2 (cullin 2).

NLRC5 has been reported to be involved in antiviral immunity; however, the underlying mechanism remains poorly understood. Here, we investigated the functional role of NLRC5 in the infection of a flavivirus, dengue virus (DENV). We found that the expression of NLRC5 was strongly induced by virus infection and IFNB or IFNG stimulation in different cell lines. Overexpression of NLRC5 remarkably suppressed DENV infection, whereas knockout of NLRC5 led to a significant increase in DENV infection. Mechanistic study revealed that NLRC5 interacted with the viral nonstructural protein 3 (NS3) protease domain and mediated degradation of NS3 through a ubiquitin-dependent selective macroautophagy/autophagy pathway. We demonstrated that NLRC5 recruited the E3 ubiquitin ligase CUL2 (cullin 2) to catalyze K48-linked poly-ubiquitination of the NS3 protease domain, which subsequently served as a recognition signal for cargo receptor TOLLIP-mediated selective autophagic degradation. Together, we have demonstrated that NLRC5 exerted an antiviral effect by mediating the degradation of a multifunctional protein of DENV, providing a novel antiviral signal axis of NLRC5-CUL2-NS3-TOLLIP. This study expands our understanding of the regulatory network of NLRC5 in the host defense against virus infection.

Possible connection between intestinal tuft cells, ILC2s and obesity.

Intestinal tuft cells (TCs) are defined as chemosensory cells that can "taste" danger and induce immune responses. They play a critical role in gastrointestinal parasite invasion, inflammatory bowel diseases and high-fat diet-induced obesity. Intestinal IL-25, the unique product of TCs, is a key activator of type 2 immunity, especially to promote group 2 innate lymphoid cells (ILC2s) to secret IL-13. Then the IL-13 mainly promotes intestinal stem cell (ISCs) proliferation into TCs and goblet cells. This pathway formulates the circuit in the intestine. This paper focuses on the potential role of the intestinal TC, ILC2 and their circuit in obesity-induced intestinal damage, and discussion on further study and the potential therapeutic target in obesity.

Electro-Optical Characteristics of Polymer Dispersed Liquid Crystal Doped with MgO Nanoparticles.

In this paper, inorganic oxide MgO nanoparticles-doped polymer dispersed liquid crystal (PDLC) films were made from a mixture of the prepolymer, SLC1717 liquid crystal, and MgO nanoparticles by the polymerization induced phase separation (PIPS) process. To observe the effect of MgO concentration, PDLC was dispersed with 0.2, 0.4, 0.6, and 0.8 wt.% MgO. Electro-optical properties of the films have been investigated using LCD parameter meter and Scanning Electron Microscope (SEM) at room temperature. It is established that MgO nanoparticles affect the microstructure of PDLC films significantly because of the formed agglomerates of MgO nanoparticles. Results show an improvement in the electro-optical properties and a decrease in the driving voltage for doped systems with MgO nanoparticles. When the doping amount of MgO is 0.8 wt.%, the threshold voltage (Vth) is reduced to about 7.5 V. Therefore, MgO-doped PDLC is expected to become an excellent choice in the field of energy-saving.

Advances in the establishment of rodent model of alcoholic liver disease / 中国热带医学

@#Abstract:Alcoholic liver disease (ALD) is one of the most common liver diseases in the world. Long-term alcoholism causes a series of pathological changes in the liver, which eventually leads to the occurrence of liver diseases with an increasing incidence. At present, significant progress has been made in the pathogenesis and pathological development of alcoholic liver disease, but the relevant mechanism of ALD has not been thoroughly studied. It is necessary to improve the existing animal model or establish a new, more comprehensive animal ALD model to simulate human ALD. Experimental animal models of ALD, especially rodents, are often used to simulate human ALD, and the ideal rodent ALD model can effectively simulate all aspects of alcohol in human liver. But so far, the commonly used animal models all have certain defects, and there is no complete animal model that can simulate human ALD. This paper reviewed the pathogenesis of ALD, related methods and influencing factors of ALD model, and provided a theoretical basis for relevant researchers to establish the ALD rodent model. 

Development of cell culture infectious clones for hepatitis C virus genotype 1b and transcription analysis of 1b-infected hepatoma cells.

Globally, hepatitis C virus (HCV) genotype 1b is the most prevalent, and its infection has been found to associate with a higher risk of hepatocellular carcinoma (HCC) than other genotype viruses. However, an efficient infectious HCV genotype 1b culture system is unavailable, which has largely hampered the study of this important genotype virus. In this study, by using a systematic approach combining the sequences of infectious 1a TNcc clone and adaptive mutations, we succeeded in culture adaption of two full-length 1b clones for the reference strain Con1 and a clinical isolate A6, and designated as Con1cc and A6cc, respectively. Con1cc and A6cc replicated efficiently in hepatoma Huh7.5.1 cells, released HCV infectivity titers of 104.1 and 103.72 focus forming units per milliliter, respectively, and maintained the engineered mutations after passages. Both viruses responded to sofosbuvir and velpatasvir in a dose-dependent manner. With culture infectious 1b clones, we characterized the transcriptomes of 1b Con1cc-infected cells, in comparison with 2a-infected and uninfected cells. In conclusion, we have developed two infectious clones for genotype 1b and shown a novel strategy for culture adaptation of HCV isolates by using a genetically close backbone sequence. Furthermore, this study provides transcriptional landscape of HCV 1b-infected hepatoma cells facilitating the study of genotype 1b infection.

Long-chain fatty acyl-coenzyme A suppresses hepatitis C virus infection by targeting virion-bound lipoproteins.

Hepatitis C virus (HCV) is a leading cause of chronic hepatitis and end-stage liver diseases. Mature HCV virions are bound by host-derived lipoproteins. Lack of an HCV vaccine warrants a major role of antiviral treatment in the global elimination of hepatitis C. Although direct-acting antivirals (DAAs) are replacing the interferon-based treatment and have dramatically improved the cure rate, the presence of viral variants resistant to DAAs, HCV genotype/subtype-specific efficacy, and high cost of DAAs argue novel and affordable regimens. In this study, we identified the antiviral effects of long-chain fatty acyl-coenzyme A (LCFA-CoA) against the infections of HCV genotypes 1-6 through targeting mature HCV-bound lipoproteins, suggesting novel mechanism(s) of antiviral different from those used by host-targeting agents or DAAs. We found that the antiviral activity of LCFA-CoA relied on the long-chain saturated fatty acid and the CoA group, and was enhanced when combined with pegylated-interferon or DAAs. Importantly, we demonstrated that LCFA-CoA efficiently inhibited the infection of HCV variants carrying DAA-resistant mutations. The mechanistic study revealed that LCFA-CoA specifically abolished the attachment and binding steps and also inhibited the cell-to-cell viral transmission. LCFA-CoA targeted mature HCV-bound lipoproteins, but not apolipoproteins B or E. In addition, LCFA-CoA could also inhibit the infection of the dengue virus. Our findings suggest that LCFA-CoA could potentially serve as a supplement HCV therapy, particularly for the DAA-resistant HCV variants. Taken together, LCFA-CoA may be further developed to be a novel class of antivirals with mechanism(s), different from host-targeting agents or DAAs, of targeting the components associated with mature HCV virions.

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.

Co-occurrence patterns between bacterial and fungal communities in response to a vegetation gradient in a freshwater wetland.

Vegetation dynamics are known to influence belowground microbial community diversity and ecosystem processes in wetlands. However, the knowledge on microbe-microbe interactions in response to vegetation changes is scarce. In this study, we investigated how bacterial and fungal community composition, as well as bacterial-fungal community interactions, altered along a vegetation gradient in the Poyang Lake wetland. Surface soil and sediment samples were collected from three vegetation zones: dense, sparse, and naked. Vegetation zones differed in terms of dominant plant species, plant diversity, and vegetation coverage. Using Illumina MiSeq sequencing and network analysis of bacteria 16S rRNA and fungal ITS genes, we found that both bacterial and fungal community profiles varied according to vegetation conditions; in particular, the dense vegetation zone facilitated higher microbial abundance and a greater fungi to bacteria ratio. Co-occurrence analysis revealed that fungi-bacteria interactions were strong on vegetated zones, especially in the dense vegetation zone. However, a weak fungi-bacteria association was observed in the naked zone. Our results indicated that aboveground vegetation may act as a hotspot for organic matter accumulation, microbial growth, and microbe-microbe interactions, whereas fungi and bacteria prefer to distribute into niches based on their own nutritional preferences and functional specificity in bare ground.

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.

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.

Microarray-based identification of genes associated with prognosis and drug resistance in ovarian cancer.

The outcome for patients with ovarian cancer (OC) is poor because of drug resistance. Therefore, identification of factors that affect drug resistance and prognosis in OC is needed. In the present study, we identified 131 genes significantly dysregulated in 90 platinum-resistant OC tissues compared with 197 sensitive tissues, of which 30 were significantly associated with disease-free survival (DFS; n = 16), overall survival (OS; n = 6), or both (n = 8) in 489 OC patients of the The Cancer Genome Atlas cohort. Of these 30 genes, 17 were significantly upregulated and 13 were downregulated in the 90 resistant tissues, and with one exception, all of the up-/downregulated genes in resistant tissues were predictors of shorter DFS or/and OS. LAX1, MECOM, and PDIA4 were independent risk factors for DFS, and KLF1, SLC7A11, and PDIA4 for OS; combining these genes provided more accurate predictions for DFS and OS than any of the genes used individually. We further verified downregulation of PDIA4 protein in 51 specimens of patients with OC (24 drug resistant's and 27 sensitive's), which confirmed that downregulated PDIA4 predicted DFS and OS. PDIA4 also consistently predicted OS in a larger sample of 1656 patients with OC. These 30 genes, particularly the PDIA4, could be therapeutic targets or biomarkers for managing OC.

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.