Abrus agglutinin suppresses human hepatocellular carcinoma in vitro and in vivo by inducing caspase- mediated cell death

Aim： Abrus agglutinin （AGG） from the seeds of Indian medicinal plant Abrus precatorius belongs to the class II ribosome inactivating protein family. In this study we investigated the anticancer effects of AGG against human hepatocellular carcinoma in vitro and in vivo.
Methods： Cell proliferation, DNA fragmentation, Annexin V binding, immunocytofluorescence, Western blotting, caspase activity assays and luciferase assays were performed to evaluate AGG in human liver cancer cells HepG2. Immunohistochemical staining and TUNEL expression were studied in tumor samples of HepG2-xenografted nude mice.
Results： AGG induced apoptosis in HepG2 cells in a dose- and time-dependent manner. AGG-treated HepG2 cells demonstrated an increase in caspase 3/7, 8 and 9 activities and a sharp decrease in the Bcl-2/Bax ratio, indicating activation of a caspase cascade. Co-treatment of HepG2 cells with AGG and a caspase inhibitor or treatment of AGG in Bax knockout HepG2 cells decreased the caspase 3/7 activity in comparison to HepG2 cells exposed only to AGG. Moreover, AGG decreased the expression of Hsp90 and suppressed Akt phosphorylation and NF-κB expression in HepG2 cells. Finally, AGG treatment significantly reduced tumor growth in nude mice bearing HepG2 xenografts, increased TUNEL expression and decreased CD-31 and Ki-67 expression compared to levels observed in the untreated control mice bearing HepG2 cells.
Conclusion： AGG inhibits the growth and progression of HepG2 cells by inducing caspase-mediated cell death. The agglutinin could be an alternative natural remedy for the treatment of human hepatocellular carcinomas.     

Berbamine exhibits potent antitumor effects on imatinib-resistant CML cells in vitro and in vivo

Aim The aim of this study was to explore the effects and mechanism of berbamine on imatinib-resistant BCR-ABL-positive human leukemia K562 （K562-r） cells in vitro and in vivo. Methods：Cell viability was measured by MTT assay, and apoptotic morphology changes were detected by fluorescence microscopy. The apoptosis rate was measured by flow cytometric assay, mdr-1 mRNA levels were determined by RT-PCR. Bcl-2 family proteins, cytochrome c（ cyt C） , poly （ADP-ribose） polymerase （PARP）, and P-glycoprotein were detected by Western blot. BALB/c nu/nu mice were injected with K562-r cells subcutaneously. Tumor-bearing mice were treated intravenously with berbamine.
Results： MTT tests revealed that berbamine significantly inhibited K562-r cell proliferation and increased the chemosensitivity of K562-r cells to imatinib. The apoptosis rate was significantly increased following treatment with 21.2μmol/L berbamine; formation of typical apoptotic blebs was apparent, as observed by fluorescence microscopy. Expression levels of mdr-I mRNA and P-gp protein were high in untreated K562-r cells and significantly down-regulated by berbamine treatment. Berbamine-treated K562-r cells also exhibited down-regulated expression of the anti-apoptotic proteins Bcl-2 and Bcl-XL up-regulated expression of the apoptotic proteins Bax and cytoplasmic cyt C, and stimulated proteolytic cleavage of PARP. In addition, berbamine also suppressed the growth of K562-r xenotransplanted tumors in vivo.
Conclusion Berbamine inhibited proliferation of K562-r ceils both in vitro and in vivo. Berbamine-induced apoptosis in K562-r cells appeared to occur through a mechanism involving Bcl-2 family proteins, as well as mdr-1 mRNA and P-gp pro- tein. Berbamine in combination with imatinib restored the chemo-sensitivity of K562-r cells to imatinib. Our findings suggest that berbamine may be useful in treating imafinib-resistant CML patients.     

Quercetin sensitizes human glioblastoma cells to temozolomide in vitro via inhibition of Hsp27

Aim： Quercetin is an effective Hsp27 inhibitor and has been reported to facilitate tumor cell apoptosis. The aim of this study was to investigate whether quercetin could sensitize human glioblastoma cells to temozolomide （TMZ） in vitro.
Methods： Both U251 and U87 human glioblastoma cells were treated with quercetin and/or TMZ for 48 h. Cell viability was detected using the MTT assay. Cell apoptosis was analyzed with caspase-3 activity kits and flow cytometry. Hsp27 expression and phosphorylation were examined using Western blot analysis. RNA interference using Hsp27 siRNA oligos was performed to knock down the gene expression of Hsp27.
Results： TMZ （200 or 400 μmol/L） alone effectively inhibited the viability of U251 and U87 cells. When combined with quercetin （30 μmol/L）, TMZ （100 μmol/L） significantly inhibited the cell viability, and the inhibition of TMZ （200 and 400 μmol/L） was enhanced. TMZ or quercetin anole did not affect caspase-3 activity and cell apoptosis, while TMZ combined with quercetin significantly increased caspase-3 activity and induced cell apoptosis. TMZ anole significantly increased Hsp27 phosphorylation in U251 and U87 cells, while quercetin or Hsp27 siRNA oligos combined with TMZ attenuated TMZ-induced Hsp27 phosphorylation and significantly inhibited Hsp27 expression.
Conclusion： Combined treatment with TMZ and quercetin efficiently suppressed human glioblastoma cell survival in vitro.     

Synergistic effect of combining paeonol and cisplatin on apoptotic induction of human hepatoma cell lines

Aim： To investigate whether paeonol （Pae） has synergistic effects with cisplatin （CDDP） on the growth-inhibition and apoptosis-induction of human hepatoma cell lines HepG2 and SMMC-7721. Methods： The cytotoxic effect of drugs was measured by 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyl-tetrazolium bromide assay. The coefficient of drug interaction was used to analyze the nature of drug interactions. Morphological changes were observed by acridine orange fluorescence staining. Cell cycle and the apoptosis rate were detected by flow cytometry. Bcl-2 and Bax expression were assayed by immunohistochemical staining. Results： Pae or CDDP had antiproliferative effect on the 2 cell lines in a dose-dependent manner, with different sensitivities to drugs. More interestingly, a synergistic inhibitory effect on the viability of the 2 cell lines was observed after treatment with a combination of Pae （15.63, 31.25, and 62.5 mg/L） with various concentrations of CDDP. Further study showed typical morphological changes of apoptosis if the cells were exposed to the two agents for 24 h. The apoptotic rate of the cells with combination treatment was significantly higher than that of cells treated with Pae or CDDP alone. The expression of Bcl-2 decreased and that of Bax increased in the treated groups, especially in the combination group, with the ratio of Bcl-2/Bax decreasing correspondingly. Additionally, a combination of Pae with CDDP resulted in a stronger S phase arrest, compared with Pae or CDDP alone. Conclusion： Pae, in combination with CDDP, had a significantly synergistic growth-inhibitory and apoptosis-inducing effect on the 2 human hepatoma cell lines, which may be useful in hepatoma treatment.     

Activation and involvement of JNK1 ／ 2 in hydrogen peroxideinduced neurotoxicity in cultured rat cortical neurons

To investigate the role of c-Jun N-terminal protein kinase 1 and 2 (JNK1/2) and the main signal pathway for its activation in hydrogen peroxide (H202) induced apoptotic-like cortical cell death. METHODS: Using the model of oxidative stress induced by I-I202, the expression and diphosphorylation of JNK1/2 was examined by immunoblotting analysis, and neuronal apoptotic like cell death was determined by 4‘,6-diamidino-2-phenylindole (DAPI) staining.RESULTS: The elevation in diphosphorylation level of JNK1/2 (4.40-/5.61-fold vs sham control) was associated with the concentration of H202 (0-100 pmol/L) and the development of apoptotic-like cell death (11.04 %-81.01%).There was no alteration of JNK1/2 protein expression following H202 treatment and recovery at different time points. Administration with JNK1/2 antisense oligonucleotides not only significantly decreased JNK1/2 proteinexpression and activation level, but also significantly reduced cortical cell death induced by H2O2 exposure.Furthermore, both JNKI/2 diphosphorylation and apoptotic-like cell death were largely prevented by pretreat mentwith (5S, 10R)-(-)-5-methyl- 10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate (MK-801)or omission of Ca2 in incubation medium with ethylene glycol-bis(2-aminoethylether)-N,N,N‘,N‘-tetraacefic acid(EGTA). CONCLUSION: JNK1/2 is activated and participates in H202-induced apoptotic-like death in cultured rat cortical neurons mainiv via N-methvi-D-asDartate (NMDA) receptor-mediated influx of extraceUular Ca2 .     

PPAR-γ agonists inhibit TGF-β1-induced chemokine expression in human tubular epithelial cells

Aim： Peroxisome proliferator-activated receptor-γ （PPAR-γ） has a wide range of biological functions, including anti-inflammation. In this study, we investigated the inhibitory effects of PPAR-γ on transforming growth factor β1 （TGF-β1）-induced interleukin-8 （IL-8） and monocyte chemoattractant protein-1 （MCP-1） expression in renal tubular epithelial cells （HK-2）.
Methods： HK-2 cells were pretreated with 15d-PGJ2 or troglitazone （TGL） and then treated with TGF-β1. Expression of MCP-1 and IL-8 was measured using real-time PCR and ELISA.
Results： Treatment with 5 ng/mL TGF-β1 for 24 h increased both MCP-1 and IL-8 mRNA and protein levels in HK-2 cells. Both 15d-PGJ2 at 2.5 and 5 12mol/L and TGL at 2.5 12mol/L exhibited inhibitory effects on TGF-β1-induced MCP-1 expression. Additionally, 15d-PGJ2 at 2.5 and 5 μmol/L and TGL at 2.5 μmol/L inhibited TGF-β1-induced expression of IL-8.
Conclusion： PPAR-γ agonists （15d-PGJ2 and TGL） could inhibit the TGF-β1-induced expression of chemokines in HK-2 cells. Our results suggest that PPAR-γ agonists have the potential to be used as a treatment regimen to reduce inflammation in renal tubulointerstitial disease.     

Osteogenic effects of D（＋）β-3,4-dihydroxyphenyl lactic acid （salvianic acid A,SAA） on osteoblasts and bone marrow stromal cells of intact and prednisone-treated rats

Aim： Previous studies have shown that D（＋）β-3,4-dihydroxyphenyl lactic acid （salvianic acid A, SAA） has anabolic effects on prednisone （GC）-induced osteoporosis in rats. The current study aims to investigate the molecular mechanism of SAA＇s impact on osteogenesis and adipogenesis in bone marrow stromal cells in intact and GC-treated rats.
Methods： For in vitro study, newborn rat calvaria osteoblasts （rOBs） and rat bone marrow stromal cells （rMSCs） were isolated, identified and cultured with SAA at different concentrations to evaluate SAA＇s influence on osteogenesis and adipogenesis. In addition, 3-month-old Sprague-Dawley （SD） male rats were treated with distilled water, prednisone alone （3.0 mg·kg^-1·d^-1） or prednisone （3.0 mg·kg^-1·d^-1） and SAA （25 mg·kg^-1·d^-1） for 45 d. At the end point, the different groups of rMSCs were isolated by density-gradient centrifugation and cultured.
Results： （1） At 0.1-10.0 mg/L, SAA increased ALP activity, type I collagen （Coil-I） mRNA and OPG mRNA expression and stimulated nodule mineralization of rOBs. SAA （0.5 mg/L） also significantly increased the ALP activity of rMSCs without a need for osteogenesis-inducing medium. At 5.0 mg/L, SAA decreased the number of adipocytes with less lipid droplet formation from the rMSCs, which typically undergo adipocyte induction. （2） Coll-I expression was markedly decreased, whereas lipoprotein lipase （LPL） mRNA expression increased by 98% when compared with the first generation of rMSCs in GC-treated rats. The SAA-treated rats demonstrated an over 2-fold increase in Coll-I expression when compared with intact rats and further showed a significant decrease in LPL expression when compared with GC-treated rats. When rMSCs were co-cultured with SAA （0.5 mg/L） in vitro, SAA did not affect Coll-I and LPL gene expression in intact rats but significantly increased ColM and decreased LPL gene expression in GC-treated rats.
Conclusion： SAA protected bone from GC-i     

P21-activated kinase 5 plays essential roles in the proliferation and tumorigenicity of human hepatocellular carcinoma

Aim： To investigate the roles of P21-activated kinase 5 （PAK5） in proliferation and tumorigenicity of human hepatocellular carcinoma （HCC）.
Methods： HCC and matched paraneoplastictis tissue samples were obtained from 30 patients. Human HCC cell lines SMMC7721, HepG2, Hep3B, SK-HEP-1, Huh-7, and liver cell line HL-7702 were examined. The expression of PAK5 gene was studied using real-time qPCR and Western blotting. Cell proliferation was quantified with the MTT assay. Cell cycle was analyzed with flow cytometry. The
tumorigenicity of Lv-shRNA-transfected HepG2 cells was evaluated in BALB/cA nude mice.

Results： The mRNA level of PAK5 was significantly higher in 25 out of 30 HCC samples compared to the matched paraneoplastic
tissues. The HCC cell lines showed varying expression of PAK5 protein, and the highest level was found in the HepG2 cells. PAK5 gene silencing in HepG2 cells markedly reduced the cell proliferation and colony formation, and induced cell cycle arrest in the G1 phase. Furthermore, PAK5 gene silencing suppressed the tumor formation in nude mice, and significantly decreased the expression of HCC-related genes Cyclin D1 and beta-catenin.

Conclusion： PAK5 may play essential roles in the initiation and progression of human HCC. Thus, it may be an effective therapeutic target or perhaps serve as a clinical diagnostic or prognostic marker in human HCC.     

Intracellular dopamine oxidation mediates rotenone-induced apoptosis in PC12 cells

Aim: To study the role of dopamine (DA) in rotenone-induced neurotoxicity in PC12 cells. Methods: Cell viability was assessed by detecting the leakage of lactate dehydrogenase (LDH) into the medium. Apoptosis rate was measured by flow cytometry. Caspase-3-1ike activity was measured by fluorescence assay using the probe Ac-DEVD-AMC. The level of intracellular hydrogen peroxide and other peroxides in PC12 cells were quantified by loading cells with 2‘-7‘-Dichlorodihydrofluorescein diacetate (DCFH-DA) in fluorescence assay. Lactic acid was measured spectrophotometrically. The DA levels in PC 12 cells weredetermined by HPLC-ECD. Results: A 48-h incubation of PC 12 cells with rotenone caused an apoptotic cell death and elevated intracellular reactive oxygen species (ROS) and lactic acid accumulation. Intracellular DA depletion with reserpine significantly attenuated rotenone-induced ROS accumulation and apoptotic cell death. No change was found in rotenone-induced ROS accumulation when cells were co-treated with deprenyl. Brief treatment with reserpine at the end of rotenone treatment had no effect on rotenone-induced neurotoxicity. However, when cells were first incubated with deprenyl, a monoamine oxidase-B inhibitor for 30 min then co-incubated with rotenone plus deprenyl, a brief treatment with reserpine enhanced cell injury. Conclusion: Rotenone-inducedapoptosisinPC12 cells was mediated by intracellular dopamine oxidation.     

The expression of efflux and uptake transporters are regulated by statins in Caco-2 and HepG2 cells

Aim： Statin disposition and response are greatly determined by the activities of drug metabolizing enzymes and efflux/uptake transporters. There is little information on the regulation of these proteins in human cells after statin therapy. In this study, the effects of atorvastatin and simvastatin on mRNA expression of efflux （ABCB1, ABCG2 and ABCC2） and uptake （SLCO1B1, SLCO2B1 and SLC22A1） drug transporters in Caco-2 and HepG2 cells were investigated.
Methods： Quantitative real-time PCR was used to measure mRNA levels after exposure of HepG2 and Caco-2 cells to statins. Results： Differences in mRNA basal levels of the transporters were as follows： ABCC2〉ABCG2〉ABCB1〉SLCO1B1〉〉〉SLC22A1〉SLCO2B1 for HepG2 ceils, and SLCO2B1〉〉ABCC2〉ABCB1〉ABCG2〉〉〉SLC22A1 for Caco-2 cells. While for HepG2 cells, ABCC2, ABOG2 and SLCO2B1 mRNA levels were significantly up-regulated at 1, 10 and 20 pmol/L after 12 or 24 h treatment, in Caco-2 cells, only the efflux transporter ABCB1 was significantly down-regulated by two-fold following a 12 h treatment with atorvastatin. Interestingly, whereas treatment with simvastatin had no effect on mRNA levels of the transporters in HepG2 cells, in Caco-2 cells the statin significantly down-regulated ABCB1, ABCC2, SLC22A1, and SLCO2B1 mRNA levels after 12 or 24 h treatment.
Conclusion： These findings reveal that statins exhibits differential effects on mRNA expression of drug transporters, and this effect depends on the cell type. Furthermore, alterations in the expression levels of drug transporters in the liver and/or intestine may con- tribute to the variability in oral disposition of statins.     

Mangiferin activates Nrf2-antioxidant response element signaling without reducing the sensitivity to etoposide of human myeloid leukemia cells in vitro

Aim： Mangiferin is glucosylxanthone extracted from plants of the Anacardiaceae and Gentianaceae families. The aim of this study was to investigate the effects of mangiferin on Nrf2-antioxidant response element （ARE） signaling and the sensitivity to etoposide of human myeloid leukemia cells in vitro. Methods： Human HL-60 myeloid leukemia cells and mononuclear human umbilical cord blood cells （MNCs） were examined. Nrf2 protein was detected using immunofluorescence staining and Western blotting. Binding of Nrf2 to ARE was examined with electrophoretic mobility shift assay. The level of NQ01 was assessed with real-time RT-PCR and Western blotting. DCFH-DA was used to evaluate intracellular ROS level. Cell proliferation and apoptosis were analyzed using MTT and flow cytometry, respectively. Results： Mangiferin （50 pmol/L） significantly increased Nrf2 protein accumulation in HL-60 cells, particularly in the nucleus. Mangiferin also enhanced the binding of Nrf2 to an ARE, significantly up-regulated NQ01 expression and reduced intracellular ROS in HL60 cells. Mangiferin alone dose-dependently inhibited the proliferation of HL-60 cells. Mangiferin （50 mol/L） did not attenuate etoposide-induced cytotoxicity in HL-60 cells, and combined treatment of mangiferin with low concentration of etoposide （0.8 pg/mL） even increased the cell inhibition rate. Nor did mangiferin change the rate of etoposide-induced apoptosis in HL-60 cells. In MNCs, mangiferin significantly relieved oxidative stress, but attenuated etoposide-induced cytotoxicity. Conclusion： Mangiferin is a novel Nrf2 activator that reduces oxidative stress and protects normal cells without reducing the sensitivity to etoposide of HL-60 leukemia Cells in vitro. Mangiferin may be a potential chemotherapy adjuvant.     

Ginsenoside Rg1 protects mouse podocytes from aldosterone-induced injury in vitro

Aim： Aldosterone is elevated in many diseases such as hypertension, diabetic nephropathy and chronic kidney disease, etc. The aim of this study was to investigate the effects of aldosterone on intracellular ROS production and autophagy in podocytes in vitro, and to explore the possibility of ginsenoside Rg1 （Rg1） being used for protecting podocytes from aldosterone-induced injury.
Methods： MPC5 mouse podocyte cells were tested. Autophagosome and autophagic vacuole formation were examined under confocal microscopy with MDC and acridine orange staining, respectively. ROS were detected with flow cytometry. Malondialdehyde content and superoxide dismutase （T-SOD） activity were measured using commercial kits. The expression of LC3-II, beclin-1, SOD2 and catalase was measured by Western blotting.

Results： Treatment with aldosterone （10 nmol/L） significantly increased ROS generation and the expression of SOD2 and catalase in MPC5 cells. Furthermore, treatment with aldosterone significantly increased the conversion of LC3-I to LC3-II, beclin-1 expression and autophagosome formation. Co-treatment with rapamycin （1 ng/mL） or chloroquine （10 μmol/L） further increased aldosterone-induced autophagosome formation. Co-treatment with Rg1 （80 ng/mL） effectively relieved oxidative stress and increased T-SOD activity at the early stage and subsequently decreased autophagy in aldosterone-treated podocytes. Co-treatment with 3-MA （4 mmol/L） or NAC （50 mmol/L） exerted similar effects against aldosterone-induced autophagy in podocytes.

Conclusion： Aldosterone enhances ROS generation and promotes autophagy in podocytes in vitro. Ginsenoside-Rg1 effectively relieves aldosterone-induced oxidative stress, thereby indirectly inhibiting aldosterone-induced podocyte autophagy.     

Icaritin suppresses the proliferation of human osteosarcoma cells in vitro by increasing apoptosis and decreasing MMP expression

Aim： To explore whether icaritin, a prenylflavonoid derivative of the Chinese tonic herb Epimedium, could suppress the proliferation of human osteosarcoma cells in vitro, and to elucidate the mechanisms of the action.
Methods： Human osteosarcoma SaOS2 cell line was used in the present study. The proliferation of the cells was examined using MTT assay and immunofluorescence DAPI staining. Cell motility was studied with the scratch assay. Cell apoptosis was determined by Annexin V-FITC and PI double staining using flow cytometry. Western blotting and RT-PCR were used to measure the expression of mRNAs and proteins in the cells.

Results： Icaritin （5–15 μmol/L） suppressed the proliferation of SaOS2 cells in vitro in a dose-dependent manner. Furthermore, the cell motility was significantly decreased after exposure to icaritin. Moreover, icaritin （5 μmol/L） time-dependently induced the apoptosis of SaOS2 cells, markedly suppressed MMP-2 and MMP-9 expression, upregulated caspase-3 and caspase-9 expression, and increased the level of cleaved caspase-3 in the cells. Co-exposure to the caspase-3 inhibitor zVAD-fmk （10 μmol/L） compromised the icaritin-induced caspase-3 expression and apoptosis in SaOS2 cells.

Conclusion： Icaritin suppresses the proliferation of SaOS2 human osteosarcoma cells by increasing apoptosis and downregulating MMP expression.     

Paeonol protects rat vascular endothelial cells from ox-LDL-induced injury in vitro via downregulating microRNA-21 expression and TNF-α release

Aim： Paeonol （2＇-hydroxy-4＇-methoxyacetophenone） from Cortex moutan root is a potential therapeutic agent for atherosclerosis. This study sought to investigate the mechanisms underlying anti-inflammatory effects of paeonol in rat vascular endothelial cells （VECs） in vitro.
Methods： VECs were isolated from rat thoracic aortas. The cells were pretreated with paeonol for 24 h, and then stimulated with ox-LDL for another 24 h. The expression of microRNA-21 （miR-21） and PTEN in VECs was analyzed using qRT-PCR. The expression of PTEN protein was detected by Western blotting. TNF-α release by VECs was measured by ELISA.

Results： Ox-LDL treatment inhibited VEC growth in dose- and time-dependent manners （the value of IC50 was about 20 mg/L at 24 h）. Furthermore, ox-LDL （20 mg/L） significantly increased miR-21 expression and inhibited the expression of PTEN, one of downstream target genes of miR-21 in VECs. In addition, ox-LDL （20 mg/L） significantly increased the release of TNF-α from VECs. Pretreatment with paeonol increased the survival rate of ox-LDL-treated VECs in dose- and time-dependent manners. Moreover, paeonol （120 μmol/L） prevented ox-LDL-induced increases in miR-21 expression and TNF-α release, and ox-LDL-induced inhibition in PTEN expression. A dual-luciferase reporter assay showed that miR-21 bound directly to PTEN＇s 3＇-UTR, thus inhibiting PTEN expression. In ox-LDL treated VECs, transfection with a miR-21 mimic significantly increased miR-21 expression and inhibited PTEN expression, and attenuated the protective effects of paeonol pretreatment, whereas transfection with an miR-21 inhibitor significantly decreased miR-21 expression and increased PTEN expression, thus enhanced the protective effects of paeonol pretreatment.

Conclusion： miR-21 is an important target of paeonol for its protective effects against ox-LDL-induced VEC injury, which may play critical roles in development of atherosclerosis.     

Diallyl trisulfide activates NADPH oxidase by inducing the expression of NADPH oxidase subunits and translocation of both Rac2 and p67phox subunit in HL-60 cells

Objective To explore the effect and mechanism of diallyl trisulfide on the activity of NADPH oxidase in Hl-60 cells.Methods HL-60 cells were treated with DATS at a indicated concentration for 0,1,3,6,12 hours,respectively.The activity of NADPH oxidase was measured by the reduction of the yellow dye nitroblue tetrazolium(NBT).The mRNA expression of NADPH oxidase subunits,including gp91phox,p47 phox,p22 phox,Rac2 and Rac1,was detected by RT-PCR.The protein expression of p67 phox,gp91 phox and Rac2 was analyzed by Western blot.The cell membrane fractions were prepared according to the instruction of Mem-PER kit from Pierce Corp.Results The results showed that reduction ability of HL-60 cells for NBT markedly increased in a concentration-dependent manner following DATS incubation for 3 and 6 hours(P<0.05).HL-60 cells treated by DATS at a concentration of 150 μM for 3 hours have a maximal reduction effect for NBT.The results from RT-PCR indicated that mRNA expression of NADPH oxidase subunits,including p47phox,gp91 phox,p22 phox,Rac2 and Rac1,significantly increased in a concentration-dependent manner in HL-60 cells treated by DATS.The results from western blot showed that HL-60 cells following DATS incubation have a higher level expression of Rac2 and gp91phox,compared with untreated-HL-60 cells.Our results also indicated that a maximal expression level of p47phox,gp91 phox,p22 phox,Rac2 and Rac1in HL-60 cells is present at 3 hours following DATS incubation.We found that levels of both Rac2 and p67phox was reduced in the cytosolic fraction and meanwhile increased in the membrane fraction following HL-60 exposed to DATS,Which is dependent on the concentration and time of DATS treatment.Furthermore,the level of both Rac2 and p67phox located to the plasma membrane translocation was maximized following 150 μM of DATS incubation for 3 hours.Conclusions DATS induce the activation of NADPH oxidase by both up-regulating the expression of NADPH oxidase subunit and translocating the cytosolic Rac2 and p67 phox subunit to the plasma membrane in HL-60 cells.     

Bornyl caffeate induces apoptosis in human breast cancer cells in vitro via the ROS- and JNK-mediated pathways

Aim： To investigate the effects of bornyl caffeate discovered in several species of plant on human breast cancer cells in vitro and the underlying mechanisms.
Methods： Human breast cancer cell line MCF-7 and other tumor cell lines （T47D, HepG2, HeLa, and PC12） were tested. Cell viability was determined using MTT assay, and apoptosis was defined by monitoring the morphology of the nuclei and staining with Annexin V-FITC. Mitochondrial membrane potential （MMP） was measured using JC-1 under fluorescence microscopy. Intracellular reactive oxygen species （ROS） were assessed by flow cytometry. The expression of apoptosis-associated proteins was determined by Western blotting analysis.

Results： Bornyl caffeate （10, 25, and 50 μmol/L） suppressed the viability of MCF-7 cells in dose- and time-dependent manners, but neither caffeic acid nor borneol showed cytotoxicity at a concentration of 50 μmol/L. Bornyl caffeate also exerted cytotoxicity to HepG2, Hela, T47D, and PC12 cells. Bornyl caffeate dose-dependently induced apoptosis of MCF-7 cells, increased the expression of Bax and decreased the expression of Bcl-xl, resulting in the disruption of MMP and subsequent activation of caspase-3. Moreover, bornyl caffeate triggered the formation of ROS and activated p38 and c-Jun JNK. In MCF-7 cells, the cytotoxicity of bornyl caffeate was significantly attenuated by SB203580 （p38 inhibitor）, SP600125 （JNK inhibitor）, z-VAD （pan-caspase inhibitor） or the thiol antioxidant L-NAC.

Conclusion： Bornyl caffeate exerts non-selective cytotoxicity against cancer cells of different origin in vitro. The compound induces apoptosis in human breast cancer MCF-7 cells via the ROS- and JNK-mediated pathways.