TNF related apoptosis-inducing ligand and its receptors in ocular tumors

Most of the ocular tumors have poor prognosis, and they remain a difficult problem in the area of ophthalmology. With the rapid development of molecular biology and immunologic techniques and the deep research on ocular tumor related genes, it becomes possible to diagnose and treat malignant tumors from the molecular level. The tumor necrosis factor related apoptosis-inducing ligand (TRAIL), a member of the tumor necrosis factor (TNF) super family, is a promising candidate, either alone or in combination with established cancer therapies, since it can initiate apoptosis through the activation of their death receptors. The ability of TRAIL to selectively induce apoptosis of transformed, virus-infected or tumor cells but not normal cells promotes the development of TRAIL-based cancer therapy. Here, we will review TRAIL and its receptors' structure, function, mechanism of action and application in ocular tumors therapy.

Tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis in glioma U87 cells

Studies have shown that tumor necrosis factor-related apoptosis-inducing ligand（TRAIL）exhibits strong induction of apoptosis in human glioma cells.It remains unclear whether the mitochondrion pathway,an important apoptosis signaling pathway,is involved in TRAIL-induced glioma cell apoptosis.In the present study,in vitro cultured human glioma U87 cells were treated with human recombinant soluble TRAIL.Apoptosis of glioma U87 cells,mitochondrial transmembrane potential（Δψm）,cytoplasmic cytochrome c concentration and changes in caspase-3,-8 and-9 activity following human recombinant soluble TRAIL treatment were investigated to determine the mechanism of glioma U87 cell apoptosis induced by TRAIL.Additionally,blocking caspase-8resulted in TRAIL-induced mitochondrion pathway activation,suggesting that TRAIL,through activating caspase-8,initiated a series of mitochondrial events and resulted in apoptosis of glioma U87 cells.

Utilization of Alternative Polyadenylation Signals in the Novel Human Apoptosis-Inducing Gene hap

hap, a novel human apoptosis-inducing gene which can interact with another newly discovered apoptosis-inducing geneASY, was identified, by cloning its cDNAs from human lung cell line (WI-38) cDNA library. Two major mRNA species (1.8 and 2.7 kb in length, respectively) were previously identified by Northern blot analysis of poly(A)+ RNA from human multiple tissues using partialhap cDNA as a probe. In the present work, the molecular mechanism accounting for the generation of the twohap transcripts were investigated. The rapid amplification of cDNA 3′-ends (3′-RACE) technique and the sequential Southern blot analysis, in conjunction with the sequencing analysis demonstrated that the twohap transcripts derive from the alternative polyadenylation site selection: a AATAAA signal at position 1 528–1 533 nt for the 1.8 kbhap mRNA: and a AATAAA signal at position 2 375–2 380 nt for the 2.7 kbhap mRNA. Furthermore, a number of regulatory elements withinhap 3′-untranslated region (3′-UTR) were also examined.

Polyphyllin Ⅰ enhances tumor necrosis factor-related apoptosis-inducing ligand-induced inhibition of human osteosarcoma cell growth via downregulating the Wnt/β-catenin pathway

OBJECTIVE:To investigate the synergistic effects of polyphyllin Ⅰ(PPⅠ)combined with tumor necrosis factorrelated apoptosis-inducing ligand(TRAIL)on the growth of osteosarcoma cells through downregulating the Wnt/β-catenin signaling pathway.METHODS:Cell viability,apoptosis and cell cycle distribution were examined using cell counting kit-8 and flow cytometry assays.The morphology of cancer cells was observed with inverted phase contrast microscope.The migration and invasion abilities were examined by xCELLigence real time cell analysis DP system and transwell assays.The expressions of poly(adenosine diphosphate-ribose)polymerase,C-Myc,Cyclin B1,cyclin-dependent kinases 1,N-cadherin,Vimentin,Active-β-catenin,β-catenin,p-glycogen synthase kinase 3β(GSK-3β)and GSK-3βwere determined by Western blotting assay.RESULTS:PPⅠ sensitized TRAIL-induced decrease of viability,migration and invasion,as well as increase of apoptosis and cell cycle arrest of MG-63 and U-2 OS osteosarcoma cells.The synergistic effect of PPⅠwith TRAIL in inhibiting the growth of osteosarcoma cells was at least partially realized through the inactivation of Wnt/β-catenin signaling pathway.CONCLUSION:The combination of PPⅠ and TRAIL is potentially a novel treatment strategy of osteosarcoma.

AIFM1 variants associated with auditory neuropathy spectrum disorder cause apoptosis due to impaired apoptosis-inducing factor dimerization

Auditory neuropathy spectrum disorder(ANSD)represents a variety of sensorineural deafness conditions characterized by abnormal inner hair cells and/or auditory nerve function,but with the preservation of outer hair cell function.ANSD represents up to 15%of individuals with hearing impairments.Through mutation screening,bioinformatic analysis and expression studies,we have previously identified several apoptosis-inducing factor(AIF)mitochondria-associated 1(AIFM1)variants in ANSD families and in some other sporadic cases.Here,to elucidate the pathogenic mechanisms underlying each AIFM1 variant,we generated AIF-null cells using the clustered regularly interspersed short palindromic repeats(CRISPR)/CRISPR-associated protein 9(Cas9)system and constructed AIF-wild type(WT)and AIF-mutant(mut)(p.T260A,p.R422W,and p.R451Q)stable transfection cell lines.We then analyzed AIF structure,coenzyme-binding affinity,apoptosis,and other aspects.Results revealed that these variants resulted in impaired dimerization,compromising AIF function.The reduction reaction of AIF variants had proceeded slower than that of AIF-WT.The average levels of AIF dimerization in AIF variant cells were only 34.5%-49.7%of that of AIF-WT cells,resulting in caspase-independent apoptosis.The average percentage of apoptotic cells in the variants was 12.3%-17.9%,which was significantly higher than that(6.9%-7.4%)in controls.However,nicotinamide adenine dinucleotide(NADH)treatment promoted the reduction of apoptosis by rescuing AIF dimerization in AIF variant cells.Our findings show that the impairment of AIF dimerization by AIFM1 variants causes apoptosis contributing to ANSD,and introduce NADH as a potential drug for ANSD treatment.Our results help elucidate the mechanisms of ANSD and may lead to the provision of novel therapies.

Syncytin-A Knockout Induces Placental Developmental Abnormalities Partially through Calpain1-Apoptosis-Inducing Factor-Mediated Trophoblast Apoptosis

Objective:Structural abnormalities and dysfunction of the placenta contribute to pregnancy-related complications,such as preeclampsia.Syncytin-A(synA)has been reported to be expressed in the placenta.The contribution of synA to developmental abnormalities and dysfunction of the placenta remains elusive.In this study,we aimed to explore the role of synA in placental development and functions.Methods:SynA-knockout mice were generated using the CRISPR-Cas9 method,and the phenotypes of the placenta and fetus ofsynA-knockout mice were observed.Real-time quantitative polymerase chain reaction(PCR)and routine PCR were employed to detect the genotypes of the offspring.CD31 immunohistochemistry was used to evaluate the vessel density of the placenta,and the protein levels of key molecules were measured by western blotting.Results:SynA knockout caused fetal death.Furthermore,synA-knockout mice showed placental developmental abnormalities,indicated by a thinner labyrinth layer,thicker spongiotrophoblast layer,lower blood vessel density,and significantly higher numbers of apoptotic trophoblasts,when compared with wild-type littermates.Mechanistically,synA ablation induced apoptosis-inducing factor(AIF)cleavage and nuclear localization and promoted placental trophoblast apoptosis.In addition,synA knockout increased the calpain1 protein levels.The calpain1 inhibitor calpeptin blockedsynA knockout-induced AIF cleavage,partially restoring the placental structural abnormalities ofsynA-knockout mice.Conclusions:SynA knockout leads to placental developmental abnormalities by inducing trophoblastic apoptosis via the calpain1-AIF pathway.

凋亡诱导因子(AIF)对细胞凋亡的调控

凋亡诱导因子(apoptosis-inducing factor,AIF)是一种具有凋亡诱导活性的蛋白质,定位于线粒体的膜间隙。细胞受到凋亡刺激时,AIF分子从线粒体释放到胞质,然后再易位到核,与染色体DNA结合,使染色体核周边凝集和DNA断裂成约50 kb的大片段。AIF具有凋亡诱导活性和氧化还原酶活性,但二者的作用是脱偶联的。AIF是第一个被鉴定出可以不依赖于胱天蛋白酶(caspase)信号通路而直接介导细胞发生凋亡的分子,但后来也有的报道认为AIF的凋亡活性需依赖于胱天蛋白酶。

Local anesthetic lidocaine induces apoptosis in human corneal stromal cells in vitro

AIM:To demonstrate the apoptosis-inducing effect of iidocalne on human corneal stromal(HCS)cells fn vitm,and provide experimental basis for safety anesthetic usage In clinic of ophthalmology.METHODS:In vitro cultured HCS cells were treated with lidocaine at different doses and times,and their morphology was monitored successively with inverted phase contrast microscopy.The membrane permeability of them was detected by acridine orange/ethidium bromide(AO/EB)double staining.The DNA fragmentation of them was examined by agarose gel electrophoresis,and their ultrastructure was observed by transmission electron microscopy(TEM),respectively.RESULTS:Exposure to lidocaine at doses from0.3125g/L to 20g/L induced morphological changes of HCS cells such as cytoplasmic vacuolation,cellular shrinkage,and turning round,and elevated membrane permeability of these cells in AO/EB staining.The change of morphology and membrane permeability was doseand time-dependent,while lidocaine at dose below0.15625g/L could not induce these changes.Furthermore,lidocaine induced DNA fragmentation and ultrastructural changes such as cytoplasmic vacuolation,structural disorganization,chromatin condensation,and apoptotic body appearance of the cells.CONCLUSION:Lidocaine has significant cytotoxicity on human corneal stromal cells in vitro in a dose-and time-dependent manner by inducing apoptosis of these cells.The established experimental model and findingsbased on this model here help provide new insight into the apoptosis-inducing effect of local anesthetics in eye clinic.

EGCG Enhances TRAIL-mediated Apoptosis in Human Melanoma A375 Cell Line

Tumor necrosis factor-related apoptosis-inducing ligand （TRAIL） is a promising anti-cancer agent. Epigallocatechin-3-gallate （EGCG） is a polyphenolic constituent of green tea. In this study, inhibitory effect of combined use of EGCG and TRAIL on human melanoma A375 cells was examined and the possible mechanism investigated. The cells were divided into 4 groups： control group, EGCG group （EGCG： 10, 20 μg/mL）, TRAIL group （TRAIL： 25 ng/mL） and EGCG＋TRAIL group （combined group）. The growth inhibition was measured in the A375 cells treated with different concentrations of TRAIL （（25, 50, 75, 100, 125, 150 ng/mL） by MTT assay. The apoptosis was assessed by flow cytometry. The expressions of DR4 and DR5 were detected by flow cytometry and western blotting. The activities of caspase-8 and caspase-3 were determined by colorimetric assay. The results showed that TRAIL could dose-dependently inhibit the growth of A375 cells and the IC50 of TRAIL was 150 ng/mL. The apoptosis rate was 11.8% in the TRAIL group, 5%–7% in the EGCG group and 48.9%–59.1% in the combined group. Significant difference was found in the apoptosis rate between the combined group and the EGCG or TRAIL group （P〈0.05 for each）. The expression of DR4 instead of DR5 was significantly increased in the EGCG group. The activity of caspase-3 rather than caspase-8 was substantially enhanced in the EGCG group. These results suggest that EGCG is useful for the TRAIL-based treatment for melanoma.

Expression of caspase-3 and TRAIL receptors in CD4^+ and CD8^+ T cells of SLE patients

Objective: To study the expression of caspase-3 and tumor necrosis factor-related apoptosisinducing ligand (TRAIL) receptors in the CD4+ and CD8+ T cells of systemic lupus enythematosus (SLE) patients. Methods: RT-PCR was used to analyze the expression of caspase-3 and TRAIL receptors in CD4+ and CD8+ T cells of SLE patients and normal subjects. Results: The death domain-containing TRAIL-R1/R2 as well as 'decoy' TRAIL-R3/R4 were co-expressed in majority of CD4+ and CD8+ T cells in both SLE patients and normal subjects. The CD8+ T cells from SLE patients showed significantly higher expression of caspase-3 and TRAIL-R2 than those from normal subjects,and the expression was correlated with the activity of the disease. Conclusion: The TRAIL-R2 signal pathway might contribute to the apoptosis of T cells in SLE.

Pigment epithelium-derived factor protects retinal ganglion cells from hypoxia-induced apoptosis by preventing mitochondrial dysfunction

AIM： To investigate the potential of pigment epitheliumderived factor（PEDF） to protect the immortalized rat retinal ganglion cells-5（RGC-5） exposed to Co Cl2-induced chemical hypoxia. METHODS： After being differentiated with staurosporine（SS）, RGC-5 cells were cultured in four conditions： control group cells cultured in Dulbecco ＇s modified eagle medium（DMEM） supplemented with 10% fetal bovine serum, 100 μmol/m L streptomycin and penicillin（named as normal conditions）; hypoxia group cells cultured in DMEM containing 300 μmol/m L Co Cl2; cells in the group protected by PEDF were first pretreated with 100 ng/m L PEDF for 2h and then cultured in the same condition as hypoxia group cells; and PEDF group cells that were cultured in the presence of 100 ng/m L PEDF under normal conditions. The cell viability was assessed by MTT assay, the percentage of apoptotic cells was quantified using Annexin V-FITC apoptosis kit, and intra-cellar reactive oxygen species（ROS） was measured by dichloro-dihydro-fluorescein diacetate（DCFH-DA） probe. The mitochondria-mediated apoptosis was also examined to further study the underlying mechanism of the protective effect of PEDF. The opening of mitochondrial permeability transition pores（m PTPs） and membrane potential（Δψm） were tested as cellular adenosine triphosphate（ATP） level and glutathione（GSH）. Also, the expression and distribution of Cyt C and apoptosis inducing factor（AIF） were observed.RESULTS： SS induced differentiation of RGC-5 cells resulting in elongation of their neurites and establishing contacts between outgrowths. Exposure to 300 μmol/m L Co Cl2 triggered death of 30% of the total cells in cultures within 24 h. At the same time, pretreatment with 100 ng/m L PEDF significantly suppressed the cell death induced by hypoxia（P〈0.05）. The apoptosis induced by treatment of Co Cl2 was that induced cell death accompanied with increasing intracellar ROS and decreasing GSH and ATP level. PEDF pretreatment suppressed these effects（P〈0.05）. Additionally, PEDF treatment inhibited the opening of m PTPs and suppressed decreasing of Δψm in RGC-5 cells, resulting in blocking of the mitochondrial apoptotic pathway.CONCLUSION： Pretreatment of RGC-5 cells with 100 ng/m L PEDF significantly decreases the extent of apoptosis. PEDF inhibits the opening of m PTPs and suppresses decreasing of Δψm. Moreover, PEDF also reduces ROS production and inhibits cellular ATP level＇s reduction. Cyt C and AIF activation in PEDF-pretreated cultures are also reduced. These results demonstrate the potential for PEDF to protect RGCs against hypoxic damage in vitro by preventing mitochondrial dysfunction.

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.

Targeting androgen receptor and trail： a novel treatment paradigm for breast cancer

OBJECTIVE TNF-related apoptosis-inducing ligand(TRAIL)is a promising cancer therapeutic agent due to its minimal toxicity to normal tissues and remarkable apoptotic activity in tumors.However,most breast cancer cells are resistant to TRAIL-induced apoptosis.Our objectives are to investigate the underlying molecular mechanisms and to develop strategies to overcome such resistance.METHODS To identify modulators of TRAIL-induced apoptosis,we carried out a genome wide si RNA screen.To validate the screening result,we either silenced or overexpressed the identified genes in various breast cancer cells and changes in growth and TRAIL-induced cell apoptosis were determined in vitro and in an orthotopic xenograft mouse model.Finally,we investigated whether small molecules targeting the identified genes improve the effectiveness of TRAIL-therapy.RESULTS We unexpectedly identified androgen receptor(AR)to be responsible for TRAIL resistance.While AR is classically viewed as the key factor in prostate cancer progression,we found that AR expression levels were markedly elevated in human invasive breast cancer specimens including triple-negative breast cancers(TNBC)that are highly aggressive with poor prognosis.Importantly,breast cancer cell lines express different levels of AR that correlated with their TRAIL resistance.AR overexpression in MDA-MB-231 and MDA-MB-436 cells suppressed the TRAIL sensitivity whereas knockdown of AR rendered MCF-7 and MDA-MB-453 cells sensitive to TRAIL-induced apoptosis.AR overexpression also induced TRAIL resistance in breast tumors in vivo.Further,we observed an upregulation of the TRAIL receptor,death receptor 5(DR5)in breast cancer cells,following the removal or inhibition of AR by its antagonists Casodex and MDV3100.Treatment with AR antagonists also enhanced TRAIL-induced breast cancer cell apoptosis.CONCLUSION AR signaling suppresses TRAIL-induced breast cancer cell apoptosis,in part,by suppressing DR5 expression,and a combination of AR antagonists together with TRAIL may be a novel and effective therapy for TNBC.

Accumulation of poly(adenosine diphosphate-ribose)by sustained supply of calcium inducing mitochondrial stress in pancreatic cancer cells

BACKGROUND The biochemical phenomenon defined as poly adenosine diphosphate(ADP)-ribosylation(PARylation)is essential for the progression of pancreatic cancer.However,the excessive accumulation of poly ADP-ribose(PAR)induces apoptosis-inducing factor(AIF)release from mitochondria and energy deprivation resulting in the caspase-independent death of cancer cells.AIM To investigate whether sustained calcium supply could induce an anticancer effect on pancreatic cancer by PAR accumulation.METHODS Two pancreatic cancer cell lines,AsPC-1 and CFPAC-1 were used for the study.Calcium influx and mitochondrial reactive oxygen species(ROS)were observed by fluorescence staining.Changes in enzyme levels,as well as PAR accumulation and energy metabolism,were measured using assay kits.AIF-dependent cell death was investigated followed by confirming in vivo anticancer effects by sustained calcium administration.RESULTS Mitochondrial ROS levels were elevated with increasing calcium influx into pancreatic cancer cells.Then,excess PAR accumulation,decreased PAR glycohydrolase and ADP-ribosyl hydrolase 3 levels,and energy deprivation were observed.In vitro and in vivo antitumor effects were confirmed to accompany elevated AIF levels.CONCLUSION This study visualized the potential anticancer effects of excessive PAR accumulation by sustained calcium supply on pancreatic cancer,however elucidating a clear mode of action remains a challenge,and it should be accompanied by further studies to assess its potential for clinical application.

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.

Sanguinarine-Mediated Sensitization of Cervical Cancer SiHa Cells to TRAIL

Introduction: Cervical cancer is primarily caused by the human papilloma virus (HPV), which transforms normal cervical cells into cancerous cells that are highly resistant to radiation and chemotherapy. Induction of apoptosis in transformed cells is a key strategy in successfully treating HPV-induced cervical cancer. TRAIL (tumor necrosis factor related apoptosis-inducing ligand) has been shown to selectively induce apoptosis in cancer cells by binding to death receptors and activating extrinsic pathways for apoptosis. However, certain cervical cancers—such as the cultured cell line SiHa—are remarkably resistant to TRAIL. In this study, SiHa cells were sensitized to TRAIL by using sanguinarine—derived from the plant Sanguinaria Canadensis—which is known to induce oxidative stress and lead to the upregulation of receptors for TRAIL. Methods: Cultured SiHa cells were exposed to sub-lethal doses of sanguinarine in combination with TRAIL. Cell viability changes as well as the production of reactive oxygen species (ROS) were assessed. The induction of apoptosis was investigated by assays for caspase activation. Flow cytometry was performed to analyze expression of death receptors 4/5. Results: Treatment of SiHa cells with a combination of sanguinarine and TRAIL led to a significant reduction in cell viability. Significant increase in ROS was observed and caspase activation assays confirmed the induction of apoptosis. Conclusions: The observed synergistic effect of sanguinarine and TRAIL on SiHa cells is promising for the treatment of cervical, and possibly other, HPV-induced cancers. Oxidative stress caused by sanguinarine seems to play a central role in this synergy. The precise link between reactive oxygen species and the possible upregulation of death receptors needs further investigation. This knowledge will enable us to devise more effective treatments for those who suffer from this devastating disease.

Role of Apo2L/TRAIL in immunity: Applications to rheumatoid arthritis

Rheumatoid arthritis(RA)is the most common inflammatory disease of the musculoskeletal system primarily affecting the joints.It is characterized by massive synovial hyperplasia and subsequent destruction of articular cartilage and bone.Although various aspects in the pathogenesis of RA remain unclear,genetic,environmental and of course immunological factors have been involved.Defects in apoptosis seem to play a role in both initiation and perpetuation of RA.Apo2 ligand/tumor necrosis factor(TNF)related apoptosis-inducing ligand(Apo2L/TRAIL)is a cytokine that belongs to the TNF superfamily capable of inducing apoptosis on tumor cells through activation of the extrinsic pathway.Besides this function,like other members of the TNF superfamily,Apo2L/TRAIL has been shown to exert important functions in the regulation of the immune system.Concerning pathological conditions,the Apo2L/TRAIL signaling pathway plays an important role in the response to infections,in immune surveillance against tumors and in autoimmune diseases such as RA.Furthermore,its implication in suppression of autoimmu-nity suggests that Apo2L/TRAIL has potential as therapeutic agent not only in cancer but also in autoimmune diseases.In fact,Apo2L/TRAIL-based therapies have been shown effective in various animal models of RA.This review summarizes the current knowledge on the biology of Apo2L/TRAIL and its role in RA.

TRAIL and Celastrol Combinational Treatment Suppresses Proliferation, Migration, and Invasion of Human Glioblastoma Cells via Targeting Wnt/β-catenin Signaling Pathway

Objective To investigate the mechanistic basis for the anti-proliferation and anti-invasion effect of tumor necrosis factor-related apoptosis-induced ligand(TRAIL)and celastrol combination treatment(TCCT)in glioblastoma cells.Methods Cell counting kit-8 was used to detect the effects of different concentrations of celastrol(0-16µmol/L)and TRAIL(0-500 ng/mL)on the cell viability of glioblastoma cells.U87 cells were randomly divided into 4 groups,namely control,TRAIL(TRAIL 100 ng/mL),Cel(celastrol 0.5µmol/L)and TCCT(TRAIL 100 ng/mL+celastrol 0.5µmol/L).Cell proliferation,migration,and invasion were detected by colony formation,wound healing,and Transwell assays,respectively.Quantitative reverse transcription polymerase chain reaction and Western blotting were performed to assess the levels of epithelial-mesenchymal transition(EMT)markers(zona occludens,N-cadherin,vimentin,zinc finger E-box-binding homeobox,Slug,and β-catenin).Wnt pathway was activated by lithium chloride(LiCl,20 mol/L)and the mechanism for action of TCCT was explored.Results Celastrol and TRAIL synergistically inhibited the proliferation,migration,invasion,and EMT of U87 cells(P<0.01).TCCT up-regulated the expression of GSK-3β and down-regulated the expression of β-catenin and its associated proteins(P<0.05 or P<0.01),including c-Myc,Cyclin-D1,and matrix metalloproteinase(MMP)-2.In addition,LiCl,an activator of the Wnt signaling pathway,restored the inhibitory effects of TCCT on the expression of β-catenin and its downstream genes,as well as the migration and invasion of glioblastoma cells(P<0.05 or P<0.01).Conclusions Celastrol and TRAIL can synergistically suppress glioblastoma cell migration,invasion,and EMT,potentially through inhibition of Wnt/β-catenin pathway.This underlies a novel mechanism of action for TCCT as an effective therapy for glioblastoma.

Andrographolide sensitizes prostate cancer cells to TRAIL-induced apoptosis

Tumor necrosis factor-related apoptosis-inducing ligand （TRAIL） is a promising agent for anticancer therapy. The identification of small molecules that can establish the sensitivity of prostate cancer （PCa） cells to TRAIL-induced apoptosis is crucial for the targeted treatment of PCa. PC3, DU145, JAC-1, TsuPrl, and LNCaP cells were treated with Andrographolide （Andro） and TRAIL, and the apoptosis was measured using the Annexin V/PI double staining method. Real time-polymerase chain reaction （PCR） and Western blot analysis were performed to measure the expression levels of target molecules. RNA interference technique was used to down-regulate the expression of the target protein. We established a nude mouse xenograft model of PCa, which was used to measure the caspase-3 activity in the tumor cells using flow cytometry. In this research study, our results demonstrated that Andro preferentially increased the sensitivity of PCa cells to TRAIL-induced apoptosis at subtoxic concentrations, and the regulation mechanism was related to the up-regulation of DR4. In addition, it also increased the p53 expression and led to the generation of reactive oxygen species （ROS） in the cells. Further research revealed that the DR4 inhibition, p53 expression, and ROS generation can significantly reduce the apoptosis induced by the combination of TRAIL and Andro in PCa cells. In conclusion, Andro increases the sensitivity of PCa cells to TRAIL-induced apoptosis through the generation of ROS and up-regulation of p53 and then promotes PCa cell apoptosis associated with the activation of DR4.

Traditional Chinese medicines and their active ingredients sensitize cancer cells to TRAIL-induced apoptosis

The rapidly developing resistance of cancers to chemotherapy agents and the severe cytotoxicity of such agents to normal cells are major stumbling blocks in current cancer treatments.Most current chemotherapy agents have significant cytotoxicity,which leads to devastating adverse effects and results in a substandard quality of life,including increased daily morbidity and premature mortality.The death receptor of tumor necrosis factor-related apoptosis-inducing ligand(TRAIL)can sidestep p53-dependent pathways to induce tumor cell apoptosis without damaging most normal cells.However,various cancer cells can develop resistance to TRAIL-induced apoptosis via different pathways.Therefore,it is critical to find an efficient TRAIL sensitizer to reverse the resistance of tumor cells to TRAIL,and to reinforce TRAIL’s ability to induce tumor cell apoptosis.In recent years,traditional Chinese medicines and their active ingredients have shown great potential to trigger apoptotic cell death in TRAIL-resistant cancer cell lines.This review aims to collate information about Chinese medicines that can effectively reverse the resistance of tumor cells to TRAIL and enhance TRAIL’s ability to induce apoptosis.We explore the therapeutic potential of TRAIL and provide new ideas for the development of TRAIL therapy and the generation of new anticancer drugs for human cancer treatment.This study involved an extensive review of studies obtained from literature searches of electronic databases such as Google Scholar and PubMed."TRAIL sensitize"and"Chinese medicine"were the search keywords.We then isolated newly published studies on the mechanisms of TRAIL-induced apoptosis.The name of each plant was validated using certified databases such as The Plant List.This study indicates that TRAIL can be combined with different Chinese medicine components through intrinsic or extrinsic pathways to promote cancer cell apoptosis.It also demonstrates that the active ingredients of traditional Chinese medicines enhance the sensitivity of cancer cells to TRAIL-mediated apoptosis.This provides useful information regarding traditional Chinese medicine treatment,the development of TRAIL-based therapies,and the treatment of cancer.