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.

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.

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.

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.

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.

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.