Role of TNF-related apoptosis-inducing ligand （TRAIL） in the pathogenesis of varicocele-induced testicular dysfunction

The higher frequency of varicocele in men with infertility has drawn attention and resulted in increased research at the molecular level towards treatments. The aim of this study was to investigate the role of tumor necrosis factor （TNF）-related apoptosis-inducing ligand （TRAIL） and its receptors in varicocele-induced testicular dysfunction in an experimental rat model. The rats were divided into three groups： control, sham and varicocele. Varicoceles in rats were induced by partial ligation of the left renal vein and left testes. The rats were analyzed 13 weeks after surgery. The degree of DNA fragmentation within cells in the testis was determined using terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling （TUNEL） assay. Tubule degeneration was evaluated using the Johnsen score. The expression of TRAIL and its receptors was detected by immunohistochemical and Western blotting techniques. The apoptotic index, Johnsen score and the expression of TRAIL and TRAIL receptors were examined. The data are presented as the mean-.＋s.d, and were analyzed using computer software. The KruskaI-Wallis and Dunn＇s multiple comparison tests were used in the statistical analyses. The germ cell apoptotic index was increased in rats with varicoceles when compared with the sham and control groups （P=0.0031）. The Johnsen score was significantly decreased in the varicocele group when compared with the sham and control groups （P〈O.O001）. Immunohistochemical and Western blotting analyses showed that after varicocele induction, the expression of TRAIL-R1 and TRAIL-R4 in germ cells was increased and the expression of TRAIL-R2 was decreased. There are no significant differences among the groups in terms of TRAIL and TRAIL-R3 receptor expression. The results of this study indicate that TRAIL and its receptors may have a potential role in the pathogenesis of varicocele-induced testicular dysfunction.

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.

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.

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.

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.

Vitamin E Succinic Acid enhances the effect of mDRA-6 to eradicate leukemia cells by inducing apoptosis

Objective: The aim of our study was to detect whether Vitamin E Succinic Acid (VES) could regulate the expression level of DR5 in the cells and further elucidate the potential mechanisms involving that VES enhances the effect of mDRA-6 to eradicate leukemia Raji and K562 cells. Methods: MTT method was used to detect the growth inhibition of VES and mDRA-6 to Raji and K562 cells. Annexin V-FITC/PI double staining assay was used to analysis the apoptosis of leukemia cell. Flow cytometry was used to detect the cell surface DR5 expression. Immunoblotting technique was used to detect the DR5 protein expression. Results: MTT detection showed that 10 μmol/L mDRA-6 on the cell death rates of Raji and K562 cells were 21.98% and 5.23%, respectively. While increasing concentration of VES (5 μmol/L, 10 μmol/L, 20 μmol/L) and mDRA-6 both on the cell viability of Raji or K562 cells, the mortality of Raji cells elevated to 24.67%, 35.65% (P<0.01) and 40.22% (P<0.01), respectively. Similarly, the mortality of K562 cells increase to 6%, 7.89% (P<0.01) and 8.67% (P<0.01), respectively. To further specify the increased cell death rate induced by mDRA-6 and VES, the treated cells were analyzed by Annexin-V/PI staining assay. As shown in Fig. 1, the apoptosis rates of Raji and K562 cells treated with 2 μg/mL mDRA-6 for 12 h were 20.79% and 7.74%. Compared with this, the proportion of apoptotic cells increased upon exposure to 2 μg/mL mDRA-6 combination with 10 μmol/L VES, the apoptosis rates of Raji and K562 cells were 43.18% and 16.99%, respectively. To examine the anticancer effects of a combination strategy based on mDRA-6 and VES. We analyzed whether VES could elevated the expression level of DR5 on Raji and K562 cytomembrane by FACS. Interestingly, after treated with 10 μmol/L VES for 12 h, the expression level of DR5 on Raji and K562 cell surface increased from 50.66% to 70.08%, and 15.02% to 16.38%, respectively. Immune imprinting technology test showed that, different concentrations of VES could increase Raji and K562 cell DR5 protein expression. Conclusion: VES enhances the effect of mDRA-6 to eradicate leukemia Raji and K562 cells. The proper mechanism is VES could enhance the Raji and K562 cell membrane expression of DR5, and VES can also enhance the DR5 protein expression of cells.

Downregulation of cyclooxygenase-1 is involved in gastric mucosal apoptosis via death signaling in portal hypertensive rats

Portal hypertension （PHT） gastropathy is a frequent complication of fiver cirrhosis and one of the leading causes of death from cirrhosis. Apoptosis is widely considered to be an active energy-dependent mode of cell death and a distinct entity from necrotic cell death. It is unclear whether gastric mucosal apoptosis is involved in PHT gastropa- thy. Prostaglandins （PGs） produced through cyclooxygenase （COX） are thought to play a key role in protection of the gastrointestinal mucosa from injury and apoptosis. However, the role of COX in PHT gastropathy is still not clearly understood. The aims of this study were to investigate whether （1） gastric mucosal apoptosis is involved in PHT gas- tropathy and （2） downregulation of COX contributes to this apoptosis. In this study, we show that gastric mucosal apoptosis was remarkably increased while mucosal proliferation was inhibited in PHT rats. Gastric mucosal COX- 1 was significantly suppressed at both the mRNA and protein levels, and PGE2 was reduced in PHT rats. Further, PGE2 treatment suppressed gastric mucosal apoptosis in PHT rats. However, gastric mucosal COX-2 levels did not differ between sham-operated rats and PHT rats. Gastric mucosal levels of tumor necrosis factor-α （TNF-α） and Fas ligand, but not TNF-related apoptosis-inducing ligand, were increased, and activated caspase-8 and caspase-3 levels were upregulated in PHT rats. The release of cytochrome c from the mitochondria to the cytosol was not observed in PHT rats. Our data indicate that downregulation of COX-1 is involved in gastric mucosal apoptosis via death signal- ing-mediated type-I cell death in PHT rats.

Bcl-2 degradation is an additional pro-apoptotic effect of polo-like kinase inhibition in cholangiocarcinoma cells

To examine the influence on apoptotic mechanisms following inhibition of polo-like kinases as therapeutically approach for cholangiocellular cancer treatment.METHODSAs most cholangiocarcinomas are chemotherapy-resistant due to mechanisms preventing tumor cell death, we investigated the effect of Cisplatin on cholangiocellular carcinoma (CCA) cell lines KMCH-1 and Mz-Ch-1. Polo-like kinases (PLK) are important regulators of the cell cycle and their inhibition is discussed as a potential therapy while PLK inhibition can regulate apoptotic mediators. Here, cells were treated with PLK inhibitor BI6727 (Volasertib), Cisplatin, and in combination of both compounds. Cell viability was assessed by MTT; apoptosis was measured by DAPI staining and caspase-3/-7 assay. Western blot and qRT-PCR were used to measure expression levels of apoptosis-related molecules Bax and Bcl-2.RESULTSThe cell viability in the CCA cell lines KMCH-1 and Mz-Ch-1 was reduced in all treatment conditions compared to vehicle-treated cells. Co-treatment with BI6727 and cisplatin could even enhance the cytotoxic effect of cisplatin single treatment. Thus, co-treatment of cisplatin with BI6727 could slightly enhance the cytotoxic effect of the cisplatin in both cell lines whereas there was evidence of increased apoptosis induction solely in Mz-Ch-1 as compared to KMCH-1. Moreover, PLK inhibition decreases protein levels of Bcl-2; an effect that can be reversed by the proteasomal degradation inhibitor MG-132. In contrast, protein levels of Bax were not found to be altered by PLK inhibition. These findings indicate that cytotoxic effects of Cisplatin in Mz-Ch-1 cells can be enhanced by cotreatment with BI6727.CONCLUSIONIn conclusion, BI6727 treatment can sensitize CCA cells to cisplatin-induced apoptosis with proteasomal Bcl-2 degradation as an additional pro-apoptotic effect.

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.

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.

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.

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.

The flavonoid casticin enhances TRAIL-induced apoptosis of colon cancer cells through endoplasmic reticulum stress-mediated up-regulation of DR5

Objective： The aim of this study was to explore the mechanisms by which the flavonoid casticin enhances tumor necrosis factor-related apoptosis-inducing ligand （TRAIL）-induced apoptosis in colon cancer cells. Methods： Human colon cancer HT-29 cells were treated with TRAIL or casticin. Cytotoxicity was examined by MTT assay, and apoptosis determined by morphological observation and flow cytometric analysis. Death receptor 5 （DRS）, DR4, and endoplasmic reticulum （ER） stress response markers, including glucose regulating protein 78 （GRP78）, activating transcription factor 4 （ATF4） and CHOP （CCAAT/enhancer binding protein homologous protein）, were examined with western blot. Small interfering RNA （siRNA） transfection was employed to knock down CHOP. Results： HT-29 cells were resistance to TRAIL-induced apoptosis, but casticin, at subtoxic concentrations, potentiated HT-29 cells to TRAIL-induced apoptosis. Casticin up-regulated the expression of DR5 time-and dose-dependent manners, but had no effect on the expression of DR4. Also, casticin increased the levels of ER stress response markers （GRP78, ATF4 and CHOP） in a similar way to DR5. Knockdown of CHOP by specific siRNA, or salubrinal, an ER stress inhibitor, abolished the up-regulation of DR5 and enhancement of TRAIL-induced apoptosis by casticin. Conclusion： Casticin enhances TRAIL-induced apoptosis of colon cancer cells by ER stress-mediated up-regulation of DR5.

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.

Co-delivery of TRAIL and paclitaxel by fibronectin-targeting liposomal nanodisk for effective lung melanoma metastasis treatment

Melanoma is a highly aggressive cancer which often forms metastatic tumors in the lung,leading to sharply reduced patients'survival rate.Effectively treating these tumors thus could improve late stage melanoma with lung metastasis.In this study,we fabricated a Cys-Arg-Glu-Lys-Ala with N-methylated Glu(CR(NMe)EKA)decorated disk shaped nano vehicle to co-deliver tumor necrosis factor-related apoptosis-inducing ligand(TRAIL)and paclitaxel(PTX)to lung melanoma tumor sites(TRAIL-[ND-PTX]^(CR(NMe)EKA)).These nanodisks displayed better tumor-targeting and penetration capability than spherical nanoparticles,while the fibronectin-targeting CR(NMe)EKA motif also increased the tumor accumulation of loaded drugs.The combined usage of TRAIL and PTX both killed tumor cells and reduced local nutrition supply,leading to stronger overall anti-tumor effect.This TRAIL-[ND-PTX]^(CR(NMe)EKA)system performed remarkably better than free paclitaxel and also significantly elongated survival rate of melanoma lung metastasis bearing mice,without displaying significant toxicity.Hence,this designing strategy and the fabricated nanoplatform possess potential for further development.

Improving TRAIL-induced apoptosis in cancers by interfering with histone modifications

Epigenetic regulation refers to alterations to the chromatin template that collectively establish differential patterns of gene transcription.Post-translational modifications of the histones play a key role in epigenetic regulation of gene transcription.In this review,we provide an overview of recent studies on the role of histone modifications in carcinogenesis.Since tumour-selective ligands such as tumor necrosis factor-related apoptosis-inducing ligand(TRAIL)are well-considered as promising anti-tumour therapies,we summarise strategies for improving TRAIL sensitivity by inhibiting aberrant histone modifications in cancers.In this perspective we also discuss new epigenetic drug targets for enhancing TRAIL-mediated apoptosis.