EGFR inhibitors sensitize non-small cell lung cancer cells to TRAIL-induced apoptosis

Apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand(TRAIL) can be regulated by the epidermal growth factor(EGF) signaling pathway.In this study,recombinant adenoviral vectors that encode TRAIL gene from the hTERT/RGD promoter(AdTRAIL) was combined with drugs including gefitinib,elotinib,and cetuximab that inhibit EGFR and the EGF signaling pathway in non-small cell lung cancer(NSCLC) cell lines to investigate their antitumor activity.In vitro,compared to single reagent,AdTRAIL combined with EGFR inhibitors reduced proliferation and enhanced apoptosis in H460,A549,and SW1573 cell lines.Western blot results suggested that these effects were relative to up-regulation of pro-apoptosis protein BAX and down-regulation of p-AKT.In vivo,AdTRAIL combined with cetuximab resulted in a significant growth reduction in H460 xenografts without damage to the main organs of nude mice.Histological examination and TUNEL analyses of xenografts showed that cetuximab enhanced cell apoptosis induced by AdTRAIL.These results indicate that EGFR inhibitors enhanced AdTRAIL anti-tumor activity in NSCLC cell lines and that inhibiting the AKT pathway played an important role in this enhancement.

Effect of Smac on TRAIL-induced Apoptosis of Prostate Cancer Cell Line PC-3 and the Molecular Mechanism

The effect of Smac gene on the TRAIL-induced apoptosis of the prostate cancer cell line PC-3 and the molecular mechanism were investigated. The Smac gene was transfected into PC-3 cells under the induction of liposome. The intrinsic Smac gene expression was detected by Western blotting. After treatment with TRAIL as an apoptosis inducer, in vitro cell growth activity was assayed by MTT colorimetry. The apoptosis rate of PC-3 cells was determined by annexin Ⅴ-FITC and propidium iodide staining flow cytometry. The expression of cellular XIAP and caspase-3 genes was examined by Western blotting. Smac-transfected cells (PC-3/Smac group) had significantly increased Smac protein level as compared with PC-3 controls (P<0.01). After induction with 100–200 ng/mL TRAIL for 12–36 h, cellular proliferation rate in PC-3/Smac group was significantly lower than in PC-3 controls (P<0.05). After induction with 100 ng/mL TRAIL for 24 h, the apoptosis rate in PC-3/Smac group was significantly enhanced as compared with that of PC-3 controls (P<0.05). Accordingly, the XIAP expression level was down-regulated significantly (P<0.05) and caspase-3 subunit P20 was up-regulated significantly (P<0.05). It is suggested that the over-expression of cellular Smac can inhibit inhibitor of apoptosis proteins (IAPs), enhance caspases activity and the apoptosis rate of PC-3 cells induced by TRAIL, which may provide a useful experimental basis for prostate cancer therapy.

Induction of Apoptosis in Lung Cancer Cells by TRAIL and L-leucyl-L-leucine Methyl Ester

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a member of the tumor necrosis factor superfamily that induces apoptosis in many tumor cells. Previous studies suggested that TRAIL treatment might also cause release of lysosomal cathepsin proteases to the cytosol, thus further promoting apoptosis. L-leucyl-L-leucine methyl ester (LeuLeuOMe) is a lysosome-destabilizing agent that may cause release of cathepsins into the cytosol and ensuing apoptosis. We hypothesized that a combination of TRAIL and LeuLeuOMe may synergistically promote apoptosis in lung cancer cells. The human epidermoid lung carcinoma cell line Calu-1 (TRAIL-resistant) and human large cell lung carcinoma cell line NCI-H460 (TRAIL-sensitive) were assayed for sensitivity to TRAIL and LeuLeuOMe, given alone or in different combination doses. Each agent alone induced a dose-dependent cytotoxicity, with substantially different efficacies of the two agents for the two cell types. When both agents were combined, synergistic cytotoxicity was achieved even in the TRAIL-resistant cells. TRAIL-induced cytotoxicity was completely inhibited by pan-caspase inhibitor z-VAD-fmk, but not by cysteine protease inhibitor E-64d. Conversely, E-64d totally blocked LeuLeuOMe-induced cytotoxicity. TRAIL caused mitochondrial damage, while enlarged lysosomes and lysosomal rupture were observed in LeuLeuOMe-treated cells. Our data suggest that, while TRAIL and LeuLeuOMe cause apoptosis through pathways that differ in their involvement of lysosomal cysteine proteases, mitochondrial and lysosomal desta-bilization have converging pro-apoptotic effects. Thus, the synergy of TRAIL and LeuLeuOMe may be used therapeutically to promote apoptosis in lung cancers, even those with intrinsic or acquired resistance to TRAIL.

Roscovitine sensitizes breast cancer cells to TRAIL-induced apoptosis through a pleiotropic mechanism

肿瘤坏死因素(TNF ) 联系了导致 apoptosis ligand (TRAIL/APO2L ) 是在血缘的死亡受体的约会之上导致 apoptosis 的 TNF 基因总科的一个成员。当小道对正常房间相对无毒时，它有选择地在许多转变房间导致 apoptosis。不过，胸肿瘤房间对小道的效果特别地抵抗。这里，我们报导在有 cyclin 依赖的 kinase 禁止者 roscovitine 的联合，落后于的暴露在检验的小道抵抗的乳癌房间线的多数导致了显著 apoptosis。Roscovitine 便于小道导致死亡的发信号的复杂形成和 caspase-8 的激活。FLICE 禁止的蛋白质是的 cFLIP (L) 和 cFLIP 显著地下面调整的列在后面暴露到 roscovitine 并且，确实由 siRNA 的 cFLIP isoforms 击倒敏化的胸肿瘤房间到导致小道的 apoptosis。另外，我们证明 roscovitine 强烈在胸肿瘤房间压制了 Mcl-1 表示和起来调整的 E2F1 蛋白质层次。显著地，由 siRNA 的 Mcl-1 的 silencing 敏化胸肿瘤房间到导致小道的 apoptosis。而且，由减少的 siRNA 的 E2F1 蛋白质击倒在导致小道的 apoptosis 的 roscovitine 的敏化的效果。在摘要，我们的结果为 roscovitine 的 pro-apoptotic 影响揭示 pleitropic 机制，加亮它象在在有小道的联合的乳癌的一个反肿瘤代理人的潜力。

Piperlongumine inhibits cell growth and enhances TRAIL-induced apoptosis in prostate cancer cells

Objective: To investigate whether piperlongumine can sensitize prostate cancer cells to tumor necrosis factor-related apoptosisinducing ligand(TRAIL) and trigger apoptosis in prostate cells. Methods: Human prostate cancer cell lines PC3, LNCa P, and VCa P were cultured with piperlongumine and TRAIL. Then, cell proliferation, migration, caspase activation, apoptotic protein expressions, and death receptor expressions were measured.Results: Piperlongumine inhibited cell proliferation at low doses(<10 μM) alone and in combination with TRAIL(25 ng/m L), induced apoptosis, and suppressed cyclooxygenase activation. Additionally, piperlongumine induced expression of death receptors which potentiated TRAIL-induced apoptosis in cancer cells but did not affect decoy receptors. Piperlongumine also downregulated tumor cell-survival pathways, inhibited colony formation and migration of cancer cells alone or in combination with TRAIL. The combination of piperlongumine with TRAIL was found to be synergistic. Conclusions: Our findings indicate that piperlongumine can sensitize cancer cells to TRAIL through the upregulation of death receptors and can trigger apoptosis with the downregulation of antiapoptotic proteins.

The expression of TRAIL and its receptors in osteosarcoma cells and the apoptosis effect of a combination of TRAIL, adriamycin and IFN-γ on MG-63 cells

Objective： This study investigated the effects of rh-TRAIL with or without chemotherapeutic drugs on the apoptosis of the osteosarcoma cell line, MG-63, and the influence of chemotherapeutic drugs on changes in the expression of DR5 and YinYang 1 （YY1） in MG- 63 cells. Methods： The effects of treatment with rh-TRAIL alone and/or chemotherapetic drugs on MG-63 cell growth inhibition and apoptosis were measured using the MTT assay, FACS analysis ofAunexin V labeled cells, and the mRNA changes of DR5 and YY1 were detected by RT-PCR. Results： Rh-TRAIL protein inhibited the growth of MG-63 cells, and this inhibition was increased by adriamycin and IFN-γ. Adriamycin and IFN-γ significantly facilitated the induction of the expression of DR5 and reduced the expression of YY1. Conclusion： The apoptosis-inducing effect of rh-TRAIL in MG-63 cells was enhanced by chemotherapeutic drugs.

Human Soluble TRAIL Protein Inducing Apoptosis in Osteosarcoma Cell

This study is to examine the effect of human recombinant soluble TRAIL （TNF-related apoptosis-inducing ligand） protein inducing apoptosis in MG-63 human osteosarcoma cells. The inhibitive rates of TRAIL to MG-63 cells were detected by MTT assay. The apoptosis induced by TRAIL in MG-63 human osteosarcoma cells was analyzed with FACS and TUNEL and the apoptotic bodies were observed by transmission electron microscope. MTT assay showed that the inhibitive rates of 500, 1 000, 2 000 and 4 000 ng/mL TRAIL for 24 h were 10.1%, 24.3%, 50.6% and 97.7% respectively. Flow cytometric analysis showed that after MG-63 cells were treated with 2 gg/mL TRAIL for 6 h, obvious apoptotic peak would immediately appear before diploid peak. Human soluble TRAIL protein can quickly kill MG-63 osteosarcoma cells selectively, and may have potential value for clinical treatment of osteosarcoma.

ERK1/2-mediated Cytoplasmic Accumulation of hnRNPK Antagonizes TRAIL-induced Apoptosis through Upregulation of XIAP in H1299 Cells

Objective Tumor necrosis factor-related apoptosis-inducing ligand （TRAIL） resistance greatly limits the clinical therapeutic efficacy of TRAIL. Elucidating the molecular mechanism underlying TRAIL resistance will be fundamental to resolving this problem. Methods Nuclear and cytoplasmic protein extraction and immunofluorescence （IF） assay were used to detect changes in heterogeneous nuclear ribonucleoprotein K （hnRNPK） localization in H1299 cells. The evaluation of cell apoptosis in cells transfected with GFP-hnRNPK, GFP-hnRNPK S284/353A, or GFP-hnRNPK S284/353D mutant was performed using cleaved caspase-3 antibody. The gene expression of XIAP was tested by quantitative RT-PCR. Results Previously, we reported that hnRNPK antagonized TRAIL-induced apoptosis through inhibition of PKC-mediated GSK313 phosphorylation. In this study, we further demonstrate that TRAIL treatment induces cytoplasmic accumulation of hnRNPK in H1299 cells. The hnRNPK localized in the cytoplasm has a higher capacity to antagonize TRAIL-induced apoptosis. Both ERK1/2 signaling inhibitor U0126 and ERK-phosphoacceptor-site mutant （GFP-hnRNPK S284/353A） diminish cytoplasmic accumulation of hnRNPK induced by TRAIL. Moreover, we show that XlAP is involved in hnRNPK-mediated TRAIL resistance in H2299 cells. Conclusion Taken together, these results give new insights into the understanding of the molecular mechanism associated with TRAIL resistance in lung adenocarcinoma.

Plumbagin Enhances TRAIL-mediated Apoptosis through Up-regulation of Death Receptor in Human Melanoma A375 Cells

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anti-cancer agent. However, emergence of drug resistance limits its potential use. Plumbagin is a natural quinonoid compound isolated from plant. In this study, induced apoptosis effect of the combined treatment with plumbagin and TRAIL on human melanoma A375 cell line was examined and possible mechanism was investigated. The cells were divided into four groups: control group, plumbagin group (plumbagin, 5 or 10 μmol/L), TRAIL group (TRAIL, 30 ng/mL) and plumbagin+TRAIL group (combined treatment group). The apoptosis, and the expression of DR4 and DR5 were detected by flow cytometry. The activities of caspase-8 and caspase-3 were determined by colorimetric assay. The results showed that the apoptosis rate was 8.3% in TRAIL group, 10.35%–16.94% in plumbagin group and 52.39%–65.39% in combined treatment group, respectively, with the difference being significant between combined treatment group and plumbagin or TRAIL group (P<0.05 for each). Moreover, plumbagin alone could markedly up-regulate DR5 mRNA and protein expression, and slightly increase DR4 mRNA and protein expression. Treatment of human melanoma A375 cells with plumbagin resulted in the activation of Caspase-3, but not Caspase-8. These results suggest that plumbagin might be useful for TRAIL-based treatment for melanoma.

Induction of Apoptosis by Recombinant Soluble Human TRAIL in Jurkat Cells

Objective To investigate the therapeutic potential of tumor necrosis factor （TNF）-related apoptosis-inducing ligand （TRAIL）, a member of the TNF superfamily, and to analyze TRAIL-induced apoptosis in Jurkat cells. Methods Expression of TRAIL receptors （DR4 and DR5） was detected by reverse transcriptase-polymerase chain reaction （RT-PCR）. Cytotoxic effects were determined by colony formation assay and a cell counting kit. The effects of recombinant TRAIL on apoptosis of Jurkat cells were determined by DNA fragmentation （DNA ladder） and PI staining. Changes in mitochondrial membrane potential were detected with JC-1 fluorescence. Results TRAIL inhibited the proliferation and induced intemucleosomal DNA fragmentation （characteristic of apoptosis） and loss of mitochondrial membrane potential. Conclusion Recombinant soluble TRAIL can be used as a therapy for cancer.

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.

Fascaplysin sensitizes cells to TRAIL-induced apoptosis through upregulating DR5 expression

This study investigated the molecular mechanism of anti-tumor effect of fascaplysin, a nitrogenous red pigment firstly isolated from a marine sponge. Microarray analysis show that the TNF and TNF receptor superfamily in human umbilical vein endothelial cells (HUVEC) and human hepatocarcinoma cells (BEL-7402) were significantly regulated by fascaplysin. Western Blot results reveal that fascaplysin increased the expression of cleaved caspase-9, active caspase-3, and decreased the level of procaspase-8 and Bid. Flow cytometry and cytotoxicity tests indicate that fascaplysin sensitized cells to tumor necrosis-related apoptosis-inducing ligand-(TRAIL) induced apoptosis, which was markedly blocked by TRAIL R2/Fc chimera, a dominant negative form of TRAIL receptor DR5. Therefore, our results demonstrate that fascaplysin promotes apoptosis through the activation of TRAIL signaling pathway by upregulating DR5 expression.

Ellagic acid inhibits gastric cancer cells by modulating oxidative stress and inducing apoptosis

Objective:To evaluate the anticancer effect of ellagic acid on gastric cancer cells.Methods:MTT assay was used to evaluate the effect of ellagic acid at different concentrations(0.5-100μg/mL)on gastric cancer AGS cells.RT-qPCR and Western blot analyses were applied to assess apoptosis(BCL-2,CASP-3,and BAX)and autophagy(LC3,ATG5,and BECN1)in AGS cells treated with ellagic acid.The expression of invasion-related markers including TP53,CDKN2A,and PTEN was determined.In addition,cell cycle markers including cyclin A,B,D,and E were measured by ELISA.Oxidative stress markers were evaluated using spectrophotometry.Results:Ellagic acid inhibited the proliferation of AGS cells in a concentration-and time-dependent manner.The expression of BCL-2 was significantly decreased(P<0.05)and CASP-3 and BAX were markedly increased(P<0.01)in AGS cells treated with ellagic acid.However,this compound induced no significant changes in the expression levels of LC3,ATG5,and BECN1(P>0.05).Moreover,the oxidative stress markers including SOD,TAC,and MDA were increased by ellagic acid(P<0.01).Conclusions:Ellagic acid can inhibit cell proliferation,induce apoptosis,and modulate oxidative stress in AGS cells.However,further in vivo and molecular studies are needed to verify its anticancer efficacy.

The effect of celastrol in combination with 5-fluorouracil on proliferation and apoptosis of gastric cancer cell lines

Background:Despite the availability of chemotherapy drugs such as 5-fluorouracil(5-FU),the treatment of some cancers such as gastric cancer remains challenging due to drug resistance and side effects.This study aimed to investigate the effect of celastrol in combination with the chemotherapy drug 5-FU on proliferation and induction of apoptosis in human gastric cancer cell lines(AGS and EPG85-257).Materials and Methods:In this in vitro study,AGS and EPG85-257 cells were treated with different concentrations of celastrol,5-FU,and their combination.Cell proliferation was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT)assay.The synergistic effect of 5-FU and celastrol was studied using Compusyn software.The DNA content at different phases of the cell cycle and apoptosis rate was measured usingflow cytometry.Results:Co-treatment with low concentrations(10%inhibitory concentration(IC10))of celastrol and 5-FU significantly reduced IC50(p<0.05)so that 48 h after treatment,IC50 was calculated at 3.77 and 6.9μM for celastrol,20.7 and 11.6μM for 5-FU,and 5.03 and 4.57μM for their combination for AGS and EPG85-257 cells,respectively.The mean percentage of apoptosis for AGS cells treated with celastrol,5-FU,and their combination was obtained 23.9,41.2,and 61.9,and for EPG85-257 cells 5.65,46.9,and 55.7,respectively.In addition,the 5-FU and celastrol-5-FU combination induced cell cycle arrest in the synthesis phase.Conclusions:Although celastrol could decrease the concentration of 5-fluorouracil that sufficed to suppress gastric cancer cells,additional studies are required to arrive at conclusive evidence on the anticancer effects of celastrol.

Sm-like 5 knockdown inhibits proliferation and promotes apoptosis of colon cancer cells by upregulating p53,CDKN1A and TNFRSF10B

BACKGROUND The role of Sm-like 5(LSM5)in colon cancer has not been determined.In this study,we investigated the role of LSM5 in progression of colon cancer and the potential underlying mechanism involved.AIM To determine the role of LSM5 in the progression of colon cancer and the potential underlying mechanism involved.METHODS The Gene Expression Profiling Interactive Analysis database and the Human Protein Atlas website were used for LSM5 expression analysis and prognosis analysis.Real-time quantitative polymerase chain reaction and Western blotting were utilized to detect the expression of mRNAs and proteins.A lentivirus targeting LSM5 was constructed and transfected into colon cancer cells to silence LSM5 expression.Proliferation and apoptosis assays were also conducted to evaluate the growth of the colon cancer cells.Human GeneChip assay and bioinformatics analysis were performed to identify the potential underlying mechanism of LSM5 in colon cancer.RESULTS LSM5 was highly expressed in tumor tissue and colon cancer cells.A high expression level of LSM5 was related to poor prognosis in patients with colon cancer.Knockdown of LSM5 suppressed proliferation and promoted apoptosis in colon cancer cells.Silencing of LSM5 also facilitates the expression of p53,cyclin-dependent kinase inhibitor 1A(CDKN1A)and tumor necrosis factor receptor superfamily 10B(TNFRSF10B).The inhibitory effect of LSM5 knockdown on the growth of colon cancer cells was associated with the upregulation of p53,CDKN1A and TNFRSF10B.CONCLUSION LSM5 knockdown inhibited the proliferation and facilitated the apoptosis of colon cancer cells by upregulating p53,CDKN1A and TNFRSF10B.

Paclitaxel induces human KOSC3 oral cancer cell apoptosis through caspase pathways

Background:Paclitaxel is a compound derived from Pacific yew bark that induces various cancer cell apoptosis.However,whether it also has anticancer activities in KOSC3 cells,an oral cancer cell line,is unclear.Methods:3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide,flow cytometry,and western blotting assays were carried out to assess cell viability,subG1 phase of the cell cycle,and apoptosis-related protein expression,respectively.Results:Ourfindings indicate that paclitaxel could inhibit cell viability and increase the expression of apoptotic markers,including plasma membrane blebbing and the cleavage of poly ADP-ribose polymerase in KOSC3 cells.Also,the treatment with paclitaxel remarkably elevated the percentage of the subG1 phase in KOSC3 cells.In addition,treatment with a pan-caspase inhibitor could recover paclitaxel-inhibited cell viability.Moreover,caspase-8,caspase-9,caspase-7,and BH3 interacting domain death agonist(Bid)were activated in paclitaxel-treated KOSC3 cells.Conclusions:Paclitaxel induced apoptosis through caspase cascade in KOSC3 cells.

Absent in melanoma 2 attenuates proliferation and migration and promotes apoptosis of human colorectal cancer cells by activating P38MAPK signaling pathway

Colorectal cancer(CRC)stands among the top prevalent cancers worldwide and holds a prominent position as a major contributor to cancer-related mortality globally.Absent in melanoma 2(AIM2),a constituent of the interferoninducible hematopoietic interferon-inducible nuclear antigens with 200 amino acid repeats protein family,contributes to both cancer progression and inflammasome activation.Despite this understanding,the precise biological functions and molecular mechanisms governed by AIM2 in CRC remain elusive.Consequently,this study endeavors to assess AIM2’s expression levels,explore its potential antitumor effects,elucidate associated cancer-related processes,and decipher the underlying signaling pathways in CRC.Our findings showed a reduced AIM2 expression in most CRC cell lines.Elevation of AIM2 levels suppressed CRC cell proliferation and migration,altered cell cycle by inhibiting G1/S transition,and induced cell apoptosis.Further research uncovered the participation of P38 mitogen-activated protein kinase(P38MAPK)in AIM2-mediated modulation of CRC cell apoptosis and proliferation.Altogether,our achievements distinctly underscored AIM2’s antitumor role in CRC.AIM2 overexpression inhibited proliferation and migration and induced apoptosis of CRC cells via activating P38MAPK signaling pathway,indicating AIM2 as a prospective and novel therapeutic target for CRC.

Effects of Quercetin Extracted from Flower Buds of Sophora japonica cv.jinhuai on Proliferation and Apoptosis of Human Breast Cancer MCF-7 Cells

[Objectives]To investigate the effects of quercetin extracted from flower buds of Sophora japonica cv.jinhuai on the proliferation,apoptosis and migration of human breast cancer MCF-7 cells.[Methods]MTT assay,inverted microscope observation,hoechst33342 staining,flow cytometry(FCM)and wound healing assay were adopted to investigate the proliferation,morphological changes,apoptosis level and cell migration ability of human breast cancer MCF-7 cells,respectively.[Results]The morphological changes of cells in the treatment groups included gradually decreased number,reduced volume,vague cell contour,loose intercellular connection,uneven cytoplasm distribution and increased cell debris.With the increase of drug concentration,quercetin significantly inhibited the proliferation of human breast cancer MCF-7 cells(P<0.05).The number of apoptotic bodies increased gradually.When the concentration reached 100μmol/L,a large number of nuclear fragments appeared,and the level of apoptosis was statistically different(P<0.05).The mobility and migration ability of cells showed a decreasing trend,and the differences were statistically significant(P<0.05).[Conclusions]This study can provide experimental basis for clinical application of quercetin against breast cancer.

Overcoming chemoresistance in non-angiogenic colorectal cancer by metformin via inhibiting endothelial apoptosis and vascular immaturity

The development of chemoresistance which results in a poor prognosis often renders current treatments for colorectal cancer(CRC).In this study,we identified reduced microvessel density(MVD)and vascular immaturity resulting from endothelial apoptosis as therapeutic targets for overcoming chemoresistance.We focused on the effect of metformin on MVD,vascular maturity,and endothelial apoptosis of CRCs with a non-angiogenic phenotype,and further investigated its effect in overcoming chemoresistance.In situ transplanted cancer models were established to compare MVD,endothelial apoptosis and vascular maturity,and function in tumors from metformin-and vehicle-treated mice.An in vitro co-culture system was used to observe the effects of metformin on tumor cell-induced endothelial apoptosis.Transcriptome sequencing was performed for genetic screening.Non-angiogenic CRC developed independently of angiogenesis and was characterized by vascular leakage,immaturity,reduced MVD,and non-hypoxia.This phenomenon had also been observed in human CRC.Furthermore,non-angiogenic CRCs showed a worse response to chemotherapeutic drugs in vivo than in vitro.By suppressing endothelial apoptosis,metformin sensitized non-angiogenic CRCs to chemo-drugs via elevation of MVD and improvement of vascular maturity.Further results showed that endothelial apoptosis was induced by tumor cells via activation of caspase signaling,which was abrogated by metformin administration.These findings provide pre-clinical evidence for the involvement of endothelial apoptosis and subsequent vascular immaturity in the chemoresistance of non-angiogenic CRC.By suppressing endothelial apoptosis,metformin restores vascular maturity and function and sensitizes CRC to chemotherapeutic drugs via a vascular mechanism.

Adriamycin Sensitizes Adriamycin-Resistant HL-60/ADR Cells to TRAIL-Mediated Apoptosis

OBJECTIVE To study whether an adriamycin-resistant cell line(HL-60/ADR) can be sensitized by adriamycin(ADR) to TRAIL-mediated apoptosis.METHODS The mRNA levels of the TRAIL receptor and apoptosis-related signaling molecules involved in the TRAIL-mediated apoptotic pathway were measured by RT-PCR.The protein levels of apoptotic-related signaling molecules involved in the TRAIL-mediated apoptotic pathway and processed caspase-3,caspase-9,and caspase-8 were measured by Western blots.Apoptosis was assessed by flow cytometry.Mitochondrial membrane potential was analyzed by DiOC6(3) staining.Cytotoxicity was determined by the colorimetric MTT viability/ proliferation assay.RESULTS Treatment with a combination of TRAIL and subtoxic concentrations of ADR resulted in synergistic cytotoxicity and apoptosis for both the parental HL-60 and the HL-60/ADR cells.For HL-60,there was a 5-fold potentiation and synergy in cytotoxicity for TRAIL and for HL-60/ADR,cytotoxicity to TRAIL was potentiated 6-fold with ADR.Adriamycin treatment modestly up-regulated TRAIL-R2(DR5),but had no effect on the expression of Fas-associated death domain,c-FLIP,Bcl-2,Bcl-xL,Bax,and IAP family members(cIAP-1,cIAP-2,XIAP,and survivin).The protein levels of pro-caspase-8 and pro-caspase-3 were not affected by ADR,whereas pro-caspase-9 and Apaf-1 were up-regulated.Combined treatment with TRAIL and ADR resulted in activation of caspase-9 and caspase-3,but there was no detectable processing of caspase-8 beyond the background levels.There was signif icant depolarization of the mitochondrial membrane by the combined treatment of both cell lines and it was more pronounced in the parental HL-60 cell line.The combined treatment with TRAIL and ADR resulted in 42.6% of the HL-60/ADR cells undergoing DNA fragmentation,whereas treatment with either ADR or TRAIL alone resulted in 5.46% and 21.3% DNA fragmented cells,respectively.Similar results were obtained with the HL-60 cells.CONCLUSION These fi ndings demonstrate that ADR can still signal ADR-resistant tumor cells,resulting in the modifi cation of the TRAIL-mediated signaling pathway and apoptosis.