Dioscin-induced Apoptosis of Human LNCaP Prostate Carcinoma Cells through Activation of Caspase-3 and Modulation of Bcl-2 Protein Family简

Dioscin is a natural steroid saponin derived from several plants, showing potent anti-cancer effect against a variety of tumor cell lines. In the present study, we investigated the anti-cancer activity of dioscin against human LNCaP cells, and evaluated the possible mechanism involved in its antineoplastic action. It was found that dioscin（1, 2 and 4 μmol/L） could significantly inhibit the viability of LNCaP cells in a time- and concentration-dependent manner. Flow cytometry revealed that the apoptosis rate was increased after treatment of LNCaP cells with dioscin for 24 h, indicating that apoptosis was an important mechanism by which dioscin inhibited cancer. Western blotting was employed to detect the expression of caspase-3, Bcl-2 and Bax in LNCaP cells. The expression of cleaved caspase-3 was significantly increased, and meanwhile procaspase-3 was markedly decreased. The expression of anti-apoptotic protein Bcl-2 was down-regulated, whereas the pro-apoptotic protein Bax was up-regulated. Moreover, the Bcl-2/Bax ratio was drastically decreased. These results suggested that dioscin possessed potential anti-tumor activity in human LNCaP cells through the apoptosis pathway, which might be associated with caspase-3 and Bcl-2 protein family.     

Effects of over-expression of ANXA10 gene on proliferation and apoptosis of hepatocellular carcinoma cell line HepG2

The effects of over-expression of ANXA10 gene on proliferation and apoptosis of hepatocellular carcinoma cell line HepG2 were elucidated.The human ANXA10 gene was subcloned into the lentiviral vector,PGC-FU,to generate the lentiviral expression vector,PGC-FU-ANXA10.The corrected ANXA10 was confirmed by endoenzyme digestion,and sequencing.Recombinant lentiviruses were produced by 293T cells following the co-transfection of PGC-FU-ANXA10 with the packaging plasmids pHelper1.0 and pHelper2.0.The resulting recombinant lentiviruses carrying ANXA10 were then used to infect human embryonic kidney epithelial cells,and lentiviral particles were produced.The ANXA10 expression in 293T cells was detected by using fluorescent microscope and Western blotting.HepG2 cells were infected,and divided into PGC-Fu-ANXA10 group,PGC-Fu group and HepG2 cell group.The changes of ANXA10 mRNA and protein expression were detected by using RT-PCR and Western blotting respectively.Flow cytometry and MTT assay were performed to examine the changes in cell apoptosis and proliferation respectively.The recombinant PGC-FU-ANXA10 vector was successfully constructed,the ANXA10 protein was detected by using Western blotting,and virus titer was 2×108 TU/mL.The recombinant lentiviruses were effectively infected into HepG2 cells in vitro and the infection efficiency was 70%.At 72 h after infection,the ANXA10 mRNA and protein expression levels in PGC-Fu-ANXA10 group were significantly higher than in PGC-Fu group and HepG2 cell group (P<0.05);the in vitro growth inhibition rate of HepG2 cells in PGC-Fu-ANXA10 group was 24.65%,significantly higher than that in PGC-Fu group and HepG2 cell group (P<0.05),but there was no significant difference between PGC-Fu group and HepG2 cell group;the apoptosis rate in PGC-Fu-ANXA10 group,PGC-Fu group and HepG2 cell group was (51.92±1.41)%,(19.00±1.12)% and (3.59±0.89)% respectively.The apoptosis rate in PGC-Fu-ANXA10 group was significantly higher than in PGC-Fu group and HepG2 cell group (P<0.05).The reco     

Effects of endoplasmic reticulum stress and related apoptosis on selective death of dopaminergic neurons

Objective： To explore the mechanism of endoplasmic reticulum stress（ERS） response and related apoptosis in dopaminergic neurons death. Methods： Nerve growth factor （NGF）-treatedPC12 cells were treated with 6-OHDA, MPP^＋ and rotenone. MTT assay and flow cytometry were used to measure the cell viability and the rate of celluar apoptosis induced by those neurotoxins. The expression of ERS-related gene XBP1, Grp78, CHOP, caspase-12 in drug-treated group and reserpine preincubafion group was determined with RT-polymerase chain reaction（RT-PCR） and immunohistochemistry. Results： After the exposure to different toxins, the viability of PC12 cells were decreased by 52%, 44%, 40% at 100μM6-OHDA, 75 μM MPP^＋, 20 nM rotenone for 24 h respectively. FCM assay confirmed time-dependent cell apoptosis （P 〈 0.01 ）. The gene and protein expression of XBP1, Grp78 in drug-treated group were significantly increased and reached their peaks 8 h after the treatment（P 〈 0.05）. The expression levels of CHOP and caspase-12 gene were increased 16-24 h after the treatment（P 〈 0.01 ）, but the expression level of caspase-12 was inhibited by reserpine preincubayion（P 〈 0.05）. Conclusion： The excessive ERS and relative activated cell apoptosis pathway may be associated with selective death of dopaminergic neurons.     

Upregulation and activation of caspase-3 or caspase-8 and elevation of intracellular free calcium mediated apoptosis of indomethacin-induced K562 cells

Background A nonsteroidal anti-inflammatory drug, indomethacin, has been shown to have antileukemic activity and induce leukemic cell opoptosis. This study was to elucidate the mechanism of indomethacin-induced K562 cell apoptosis. Methods K562 cells were grown in RPMI 1640 medium and treated with different doses of indomethacin (0μmol/L, 100μmol/L, 200 μmol/L, 400μmol/L, 800μmol/L) for 72 hours. The cells were harvested, and cell viability or apoptosis was analyzed using MTT assay and AO/EB stain, combining laser scanning confocal microscopy (LSCM) technique separately. For the localization and distribution of intracellular caspase-3 or caspase-8 protein, immunofluorescence assay was carried out. To reveal the activation of caspase-3 or caspase-8 in indomethacin-treated cells, Western blot detection was used. The change in intracellular free calcium was determined by Fluo-3/ Am probe labeling combined with LSCM. Results Indomethacin could lead to K562 cell apoptosis and inhibit cell viability in a concentration-dependent manner. An increased expression of intracellular caspase-3 or caspase-8 was observed at higher doses of indomethacin (400-800μmol/L). Western blot results showed upregrulation and activation in both caspase-3 and caspase-8 protein. Under indomethacin intervention, the levels of intracellular free calcium showed a significant increase. Blocking the activity of cyclooxygenase did not abolish the effects of indomethacin on K562 cell apoptosis. Conclusions Activation and upregulation of caspase-3 or caspase-8 protein were responsible for Indomethacin-induced K562 cell apoptosis. Variation of intracellular free calcium might switch on the apoptotic pathway and the proapoptotic effect of indomethacin might be cyclooxygenase-independent.     

Realgar-induced apoptosis of cervical cancer cell line Siha via cytochrome c release and caspase-3 and caspase-9 activation

Objective:To explore the molecular mechanism of realgar-induced apoptosis of cervical cancer cells.Methods:The cervical cancer cell line Siha was used to determine the cell viability and apoptosis after treatment with realgar using MTT assay and flow cytometry.The activities of caspase-3,-8,and-9 were detected by fluorescence resonance energy transfer technology and colorimetric assay,while the levels of Bcl-2,cytochrome c,and Bax were detected by Western blot method.Results:Induction of apoptosis by realgar was detected in Siha cell line in a dose-dependent manner.The apoptosis was accompanied by a significant increase in cytochrome c release and activation of caspase-3 and caspase-9 but not caspase-8.Further,the realgar-induced apoptosis was inhibited by a broad-spectrum caspase inhibitor,a caspase-3 inhibitor,and a caspase-9 inhibitor but not by a caspase-8 inhibitor.Bcl-2 and Bax protein expressions were not changed by realgar.Conclusion:The induction of apoptosis by realgar is mediated through a cytochrome c-dependent pathway,which sequentially activates caspase-9 and caspase-3.     

Holotransferrin enhances selective anticancer activity of artemisinin against human hepatocellular carcinoma cells

Artemisinin, also termed qinghaosu, is extracted from the traditional Chinese medicine ar- temesia annua L. （the blue-green herb） in the early 1970s, which has been confirmed for effectively treating malaria, Additionally, emerging data prove that artemisinin exhibits anti-cancer effects against many types of cancers such as leukemia, melanoma, etc. Artemisinin becomes cytotoxic in the presence of ferrous iron. Since iron influx is high in cancer cells, artemisinin and its analogs selectively kill can- cer cells with increased intracellular iron concentrations. This study is aimed to investigate the selective inhibitory effects of artemisinin on SMMC-7721 cells in vitro and determine the effect of holotransfer- fin, which increases the concentration of ferrous iron in cancer cells, combined with artemisinin on the anticancer activity. MTT assay was used for assessing the proliferation of SMMC-7721 cells treated with artemisinin. The induction of apoptosis and inhibition of colony formation in SMMC-7721 cells treated with artemisinin were determined by TdT-mediated dUTP nick end labeling （TUNEL） and col- ony formation assay, respectively. The results showed that artemisinin at various concentrations signifi- cantly inhibited growth, colony formation and cell viability of SMMC-7721 cells （P〈0.05）, likely due to induction of apoptosis of SMMC-7721 cells. Of interest, it was found that incubation of artemisinin combined with holotransferrin sensitized the growth inhibitory effect of artemisinin on SMMC-7721 cells （P〈0.01）. Our data suggest that treatment with artemisinin leads to inhibition of viability and pro- liferation, and apoptosis of SMMC-7721 ceils. Furthermore, we observed that holotransferrin signifi- cantly enhanced the anti-cancer activity of artemisinin. This study may provide a potential therapeutic choice for liver cancer.     

The Apoptosis of Bovine Lens Epithelial Cells Induced by Proteasome Inhibitor MG132

To investigate the effect of proteasome inhibitor MG132 on the apoptosis of bovine lens epithelial cells （BLECs）, the cells were treated with MG132 at different concentrations for12, 24 and 36 h. The cell viability was analyzed by MTT assay and the effect of MG132 on the apoptosis of BLECs was assessed by flow cytometry （FCM）. The results showed that after treatment for the same period, the inhibitory effect of MG132 on BLECs proliferation was enhanced with the increment of the concentration of MG132 （0, 2, 5, 10, μmol/L） （P〈0.05）. The 50% inhibiting concentration （IC50） was 2.03 μmol/L when the BLECs were treated with MG132 for 36 h. MG132 also induced the apop- tosis of BLECs obviously. FCM showed that the apoptosis index of the cells treated by MG132 at 2 μmol/L for 12 h was （20.24±1.51）%, and that of the control was （0.98±0.20）% respectively （P〈0.01, n=3）. It was concluded that MG132 could lead to apoptosis of BLECs. The decrease of proteasome activity may play an important role in the formation and development of cataract.     

Total saponin from root of Actinidia Valvata Dunn prevents the metastasis of human hepatocellular carcinoma cells

Objective:To extract the active component from the root of Actinidia valvata Dunn and to investigate the effects on hepatocellular carcinoma(HCC) cells in vitro.Methods:Total saponin was extracted from the root of A.valvata(TSAVD).HCC cells,such as BEL-7402,HepG2,PLC,SMMC-7721,MHCC-97-H, and MHCC-97-L,were treated with TSAVD in 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenytetrazolium bromide(MTT) assay.BEL-7402 and MHCC-97-H cells were also treated respectively with TSAVD at different concentrations for 24 h in wound healing and adhesion assays,and the effects of TSAVD on BEL-7402 and MHCC-97-H cells mobility and adhesion abilities were observed.Meanwhile,the effects of TSAVD on invasion and migration of BEL-7402 and MHCC-97-H cells were also investigated by transwell chamber in invasion and migration assays. Results:TSAVD at 1.5 mg/mL inhibited BEL-7402 cell proliferation with inhibition ratios(IRs) of 61.08%,74.12%, 84.55%at 24,48,and 72 h,respectively.Meanwhile,TSAVD inhibited MHCC-97-H proliferation in a concentrationdependent manner from 1.5 to 0.5 mg/mL,with the IR of 36%at 1.5 mg/mL at 24 h.For SMMC-7721,PLC, and HepG2,the IR was lower than 30%at 1.5 mg/mL at 24 h.In the wound healing assay,mobility abilities of BEL-7402 and MHCC-97-H cells in TSAVD treated groups were significantly weaker than those of the control group.After pretreatment for 24 h with TSAVD,adhesion abilities were reduced in both MHCC-97-H and BEL-7402 cells,with IRs of 48.50%±4.86%and 49.85%±5.25%at 200 |xg/mL.The IRs of MHCC-97-H and BEL-7402 cells in the migration assay were 49.13%±2.91%and 79.37%±0.09%at 200μg/mL In the invasion assay,IRs were 69.78%±4.88%and 82.48%±0.25%at 200μg/mL Conclusions:Of all HCC cells,the highest inhibition by TSAVD was seen for BEL-7402 proliferation.TSAVD could restrain adhesion,invasion,mobility,and migration abilities of BEL-7402 and MHCC-97-H cells in vitro.     

Expression of TRAIL and its receptors in primary hepatic carcinoma and apoptosis-inducing effect of HrsTRAIL on hepatoma cell line HepG2

Objective： To investigate the expression of tumor necrosis factor-related apoptosis-inducing ligand（TRAIL） and its receptors in primary hepatic carcinoma （PHC） and the apoptosis-inducing effect on hepatoma cell line HepG2. Methods： TRAIL and its receptors were detected by semiquantitive RT-PCR in 30 PHC and para-carcinoma tissues and two hepatoma cell lines of HepG2 and SMMC-7721. HepG2 cells were treated with human recombinant soluble TRAIL protein （HrsTRAIL） and then the viability of HepG2 cells was measured by microculture tetrazolium dye（MTT） assay and apoptosis index was demonstrated by fluorescence-activated cell sorting （FACS）. Results：TRAIL and its receptors were detectable in all PHC and para-carcinoma tissues and hepatoma cell line HepG2. TRAIL, death receptor 4 （DR4）, DR5, and decoy receptor 2 （DcR2） but not DcR1 were detectable in hepatoma cell line SMMC-7721. The expression patterns of TRAIL receptors in HepG2 were quite similar to PHC specimens. The semiquantitive results showed that the expression level of TRAIL and DcR were lower but DR was higher in hepatoma tissues than in para-carcinoma tissues. In PHC tissues, the expressions of DR were higher than DcR, while there was no difference in para-carcinoma tissues. HrsTRAIL had potent antitumor activity in a time- and dose-dependent manner. After co-incubations of the HepG2 cells in the presence of HrsTRAIL at concentration 1 000 ng/ml for 24 hours, the viability of HepG2 cells decreased to 45% and the apoptosis index reached 51%. Conclusion ：TRAIL and its receptors were expressed in both PHC tissues and para-carcinoma tissues but the expression levels were different. The lower expression of TRAIL in PHC tissues suggested that insufficient apoptosis occured in the development of PHC. High expression of DR in PHC tissues may be a self-defense mech- anism and may afford a theory of HrsTRAIL therapy for PHC. HrsTRAIL may be a potential cytotoxic drug for PHC, and it can kill majority of HepG2 cells, but minority of HepG2 were resistant to TRAIL-inducing apoptosis.     

Gene Transfection Mediated by Ultrasound and Pluronic P85 in HepG2 Cells

In order to assess whether gene transfection could be mediated by ultrasound in associa- tion with P85 and find the appropriate parameters of ultrasound irradiation, the effects of ultrasound with or without P85 on gene transfection of HepG2 cells were examined. The HepG2 cells were irra- diated by ultrasound at 1 MHz, 0.4-2.0 W/cm2 and 50% duty cycle with plasmid encoding enhanced green fluorescent protein (EGFP) as a report gene. Forty-eight h later, the expression of EGFP was detected under the fluorescence microscopy. Transfection efficacy was quantitatively assessed by flow cytometry, and cell viability was evaluated by trypan blue exclusion. The results showed that the transfection efficacy was increased with the increases in ultrasound output power and the ideal trans- fection efficacy was achieved in HepG2 cells irradiated by ultrasound at 0.8 W/cm2 for 30 s. The transfection efficacy in ulstrasound P85 group was three times higher than in single ultrasound group [(17.63±1.07)% vs (5.57±0.56)%, P<0.05]. The cell viability was about 81% and 62% in ultrasound group and ultrasound P85 group respectively. It was concluded that ultrasound in combination with P85 could mediate the gene transfection of HepG2 cells, ideal transfection efficacy was achieved by ultrasound irradiation at 0.8 W/cm2 for 30 s, and P85 could somewhat increase the damage to cells caused by ultrasound.     

Celastrus orbiculatus extract induces mitochondrial-mediated apoptosis in human hepatocellular carcinoma cells

OBJECTIVE:To investigate the apoptotic effects and underlying molecular mechanisms of Celastrus orbiculatus(C.orbiculatus) extract in human hepatocellular carcinoma cells.METHODS:Human hepatocellular carcinoma cells(HCCLM6) were treated with C.orbiculatus extract(COE) at different nontoxic concentrations(10,20,40,80,and 160 μg/mL).The effect of COE on HC-CLM6 viability was examined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT) assays.Cellular apoptosis following COE treatment was assessed by flow cytometry and western blot analysis.RESULTS:COE significantly inhibited cell viability and induced apoptosis of HCCLM6 cells in a dose-dependent manner.Apoptosis was accompanied by increased Bax expression and decreased Bcl-2 expression.In addition,COE treatment led to the release of cytochrome c,activation of caspase-3,and cleavage of poly(ADP-ribose) polymerase(PARP).Furthermore,activation of extracellular signal-regulated kinase(ERK),p38 kinase,and c-Jun N-terminal kinase(JNK) phosphorylation,and down-regulation of Akt phosphorylation was observed.CONCLUSION:COE induces mitochondrial-mediated,caspase-dependent apoptosis in HCCLM6 cells,which might be attributed to the activation of mitogen-activated protein kinase(MAPK) and inhibition of Akt signaling pathways.These data suggest that COE may be a potential treatment for human hepatocellular carcinoma.     

Fucoidan induces apoptosis of HepG2 cells by down-regulating p-Stat3

Summary： Fucoidan is one of the main bioactive components of polysaccharides. The current study was focused on the anti-tumor effects of fucoidan on human heptoma cell line HepG2 and the possible mechanisms. Fucoidan treatment resulted in cell cycle arrest and apoptosis of HepG2 cells in a dose-dependent manner detected by MTT assay, flow cytometry and fluorescent microscopy. The results of flow cytometric analysis revealed that fucoidan induced G2/M arrest in the cell cycle progression. Hoechst 33258 and Annexin V/PI staining results showed that the apoptotic cell number was increased, which was associated with a dose-dependent up-regulation of Bax and down-regulation of Bcl-2 and p-Stat3. In parallel, the up-regulation of p53 and the increase in reactive oxygen species were also observed, Which may play important roles in the inhibition of HepG2 growth by fucoidan. In the meantime, Cyelin B 1 and CDK1 were down-regulated by fucoidan treatment. Down-regulation of p-Stat3 by fucoidan resulted in apoptosis and an increase in ROS in response to fucoidan exposure. We therefore concluded that fucoidan induces apoptosis through the down-regulation of p-Stat3. These results suggest that fucoidan may be used as a novel anti-cancer agent for hepatocarcinoma.     

Effects of Betulinic Acid on Proliferation and Apoptosis in Jurkat Cells and Its In Vitro Mechanism

The anti-cancer effects of betulinic acid (BA) on Jurkat cells and its in vitro mechanism were examined by using MTT assay. Apoptosis was detected by using Hoechst33258 staining and annexin-Ⅴ/PI double-labeled cytometry. The effects of betulinic acid on the cell cycle of Jurkat cells were studied by propidium iodide method. RT-PCR and Western blotting were used to analyze the changes of cyclin D3, bcl-xl mRNA and protein levels in Jurkat cells after treatment with betulinic acid. Our results showed the proliferation of Jurkat cells was decreased in betulinic acid-treated group with a 24-h IC50 value being 70.00 μmol/L. Betulinic acid induced apoptosis of Jurkat cells in a time-and dose-dependent manner. The number of Jurkat cells treated with betulinic acid showed an increase in G0/G1 phase and decrease in S phase. After treatment with 0, 20, 60, 100 μmol/L betulinic acid for 24 h, the number of Jurkat cells was increased from (31.00±1.25)% to (58.84±0.32)% in G0/G1 phase, whereas it was decreased from (61.45±1.04)% to (35.82±1.95)% in S phase. PBMCs were less sensitive to the cytotoxicity of betulinic acid than Jurkat cells. The expressions of cyclin D3, bcl-xl mRNA and protein were decreased sharply in Jurkat cells treated with betulinic acid. It is concluded that betulinic acid is able to inhibit the proliferation of Jurkat cells by regulating the cell cycle, arrest cells at G0/G1 phase and induce the cell apoptosis. The anti-tumor effects of betulinic acid are related to the down-regulated expression of cyclin D3 and bcl-xl.     

Induction of Apoptosis in Hormone-resistant Human Prostate Cancer PC3 Cells by Inactivated Sendai Virus

Objective Inactivated Sendai virus particle[hemagglutinating virus of Japan envelope(HVJ-E)]has a potential oncolytic effect due to its ability to induce apoptosis in tumor cells.However,the molecular mechanism of apoptosis induction in cancer cells mediated by HVJ-E has not been fully elucidated.This paper aims to investigate the underlying mechanism of apoptosis induction by HVJ-E in prostate cancer cells(PC3).Methods PC3 cells were treated with HVJ-E at various MOI,and then interferon-6(IFN-S) production,and the cell viability and apoptosis were detected by ELISA,MTT-based assay and flow cytometry,respectively.Next,the roles of Jak-Stat,MAPK and Akt pathways played in HVJ-E-induced apoptosis in PC3 cells were analyzed by immunoblot assay.To further evaluate the cytotoxic effect of HVJ-E on PC3 cells,HVJ-E was intratumorally injected into prostate cancers on BALB/c-nude mice,and the tumor volume was monitored for 36 days.Results HVJ-E induced IFN-β production and activated Jak-Stat signaling pathway,which resulted in the activation of caspase-8,caspase-3,and PARP in PC3 prostate cancer cells post HVJ-E treatment.Furthermore,we observed for the first time that p38 and Jnk MAPKs in PC3 cells contributed to HVJ-E-induced apoptosis.In addition,intratumoral HVJ-E treatment displayed a direct inhibitory effect in an in vivo BALB/c nude mouse prostate cancer model.Conclusion Our findings have provided novel insights into the underlying mechanisms by which HVJ-E induces apoptosis in tumor cells.     

Sodium valproate induces mitochondria-dependent apoptosis in human hepatoblastoma cells

Background  Sodium valproate inhibits proliferation in neuroblastoma and glioma cells, and inhibits proliferation and induces apoptosis in hepatoblastoma cells. Information describing the molecular pathways of the antitumor effects of sodium valproate is limited; therefore, we explored the mechanisms of action of sodium valproate in the human hepatoblastoma cell line, HepG2.

Methods  The effects of sodium valproate on the proliferation of HepG2 cells were evaluated by the Walsh-schema transform and colony formation assays. Sodium valproate-induced apoptosis in HepG2 cells was investigated with fluorescence microscopy to detect morphological changes; by flow cytometry to calculate DNA ploidy and apoptotic cell percentages; with Western blotting analyses to determine c-Jun N-terminal kinases (JNK), p-JNK, Bcl-2, Bax, and caspase-3 and -9 protein expression levels; and using JC-1 fluorescence microscopy to detect the membrane potential of mitochondria. Statistical analyses were performed using one-way analysis of variance by SPSS 13.0 software.

Results  Our results indicated that sodium valproate treatment inhibited the proliferation of HepG2 cells in a dose-dependent manner. Sodium valproate induced apoptosis in HepG2 cells as it: caused morphologic changes associated with apoptosis, including condensed and fragmented chromatin; increased the percentage of hypodiploid cells in a dose-dependent manner; increased the percentage of annexin V-positive/propidium iodide-negative cells from 9.52% to 74.87%; decreased JNK and increased phosphate-JNK protein expression levels; reduced the membrane potential of mitochondria; decreased the ratio of Bcl-2/Bax; and activated caspases-3 and -9.

Conclusion  Sodium valproate inhibited the proliferation of HepG2 cells, triggered mitochondria-dependent HepG2 cell apoptosis and activated JNK.