[Show abstract][Hide abstract] ABSTRACT: Bacillus Calmette-Guérin (BCG) intravesical therapy against superficial bladder cancer is one of the most successful immunotherapies in cancer, though the precise mechanism has not been clarified. Recent studies have demonstrated urinary tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) levels to be higher in BCG-responsive patients than non-responders and shown that polymorphonuclear neutrophils (PMNs) migrating to the bladder after BCG instillation release large amounts of TRAIL. To establish a safer and more effective intravesical therapy than BCG, we examined whether other bacteria induced similar effects. We stimulated PMNs or peripheral blood mononuclear cells (PBMCs) with BCG or other bacteria, and then aliquots of the culture supernatants or cell lysates were assayed for TRAIL. We examined the signaling pathway regulating the release of TRAIL from PMNs and evaluated the antitumor effects of BCG or other bacteria in vitro and in vivo. We have found that Clostridium butyricum MIYAIRI 588 (CBM588) induces the release of endogenous TRAIL from PMNs as well as BCG. In addition, we have shown that matrix metalloproteinase 8 (MMP-8) is one of the key factors responsible for the release. Interestingly, TLR2/4 signaling pathway has been suggested to be important for the release of TRAIL by MMP-8. CBM588 has been proven to be as effective as BCG against cancer cells by inducing apoptosis in vivo as well as in vitro. Taken together, these results strongly suggest that CBM588 is promising for a safer and more effective therapy against bladder cancer.
Preview · Article · Jan 2013 · International Journal of Oncology
[Show abstract][Hide abstract] ABSTRACT: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is one of the most promising anti-cancer agents, but some tumor types develop resistance to TRAIL. Here, we report that chetomin, an inhibitor of hypoxia-inducible factors, is a potent enhancer of TRAIL-induced apoptosis. TRAIL or chetomin alone weakly induced apoptosis, but the combination of chetomin and TRAIL synergistically induced apoptosis in prostate cancer PC-3 cells. The combination of chetomin and TRAIL induces the activation of caspase-3, -8, -9 and -10. Among the apoptotic factors related to the TRAIL pathway, chetomin markedly decreased the X-linked inhibitor of apoptosis (XIAP) protein levels in a dose-dependent manner, but other IAP family members, TRAIL receptors and Bcl-2 family members were not altered by chetomin. Using XIAP siRNA instead of chetomin, down-regulation of XIAP sensitized PC-3 cells to TRAIL-induced apoptosis. Conversely, transient transfection of XIAP reduced the apoptotic response to combined treatment with chetomin and TRAIL. Treatment with chetomin induced a rapid decrease in XIAP protein levels but had no effect on XIAP mRNA levels. Since chetomin-mediated XIAP down-regulation was completely prevented by proteasome inhibitors, it was suggested that chetomin induces the degradation of the XIAP protein in a proteasome-dependent manner. Additionally, chetomin also sensitized renal cancer Caki-1 cells and bladder cancer UM-UC-3 cells to TRAIL-induced apoptosis via down-regulation of XIAP. Co-treatment of chetomin and TRAIL did not enhance apoptosis in normal peripheral blood mononuclear cells (PBMC). Taken together, these findings suggest that TRAIL and chetomin synergistically induce apoptosis in human urogenital cancer cells through a mechanism that involves XIAP down-regulation by chetomin.
Preview · Article · Feb 2011 · International Journal of Oncology
[Show abstract][Hide abstract] ABSTRACT: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is an endogenous cytokine that induces apoptosis in malignant tumor cells. Here, we show for the first time that lactobacilli induce TRAIL production in human peripheral blood mononuclear cells (PBMC). Treatment with lactobacilli induced TRAIL on the cell surface of PBMC and in culture medium. The TRAIL production induced by lactobacilli partially depends on IFN-alpha and IFN-gamma. Lactobacilli treatment facilitated NK activity of PBMC against prostate cancer cells. Moreover, TRAIL neutralization antibody efficiently prevented the NK activity. Our results indicate that lactobacilli facilitate NK activity through TRAIL production, and raise the possibility of a new TRAIL-based strategy against malignant tumors.
[Show abstract][Hide abstract] ABSTRACT: Allopurinol has been used for the treatment of gout and conditions associated with hyperuricemia for several decades. We explored the potential of allopurinol on cancer treatment. Allopurinol did not expose cytotoxicity as a single treatment in human hormone refractory prostate cancer cell lines, PC-3 and DU145. However, allopurinol drastically induced apoptosis of PC-3 and DU145 in combination with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), which is a promising candidate for anticancer agent but its efficacy is limited by the existence of resistant cancer cells. We examined the underlying mechanism by which allopurinol overcomes the resistance of prostate cancer cells to TRAIL. Allopurinol up-regulated the expression of a proapoptotic TRAIL receptor, death receptor 5 (DR5). Allopurinol increased DR5 protein, mRNA, and promoter activity. Using DR5 small interfering RNA (siRNA), we showed that allopurinol-mediated DR5 up-regulation contributed to the enhancement of TRAIL effect by allopurinol. Furthermore, we examined the mechanism of allopurinol-mediated DR5 up-regulation. DR5 promoter activity induced by allopurinol was diminished by a mutation of a CAAT/enhancer binding protein homologous protein (CHOP)-binding site. In addition, allopurinol also increased CHOP expression, suggesting that allopurinol induced DR5 expression via CHOP. Allopurinol possesses the activity of a xanthine oxidase (XO) inhibitor. We used XO siRNA instead of allopurinol. XO siRNA also up-regulated DR5 and CHOP expression and sensitized the prostate cancer cells to TRAIL-induced apoptosis. Here, we show the novel potential of allopurinol in cancer treatment and indicate that the combination of allopurinol with TRAIL is effective strategy to expand the TRAIL-mediated cancer therapy.
Preview · Article · Jan 2009 · Molecular Cancer Research
[Show abstract][Hide abstract] ABSTRACT: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is one of the most promising candidates for new cancer therapeutics. A current problem is that some cancers still remain resistant to TRAIL. We show for the first time that a naturally occurring flavonoid, baicalein, overcomes TRAIL resistance in cancer cells. The combination of baicalein and TRAIL effectively induced apoptosis in TRAIL-resistant colon cancer SW480 cells. Baicalein up-regulated the expression of death receptor 5 (DR5) among TRAIL receptors at the mRNA and protein levels. Suppression of this up-regulation with small interfering RNA (siRNA) efficiently reduced the apoptosis induced by TRAIL and baicalein, suggesting that the sensitization was mediated through DR5 induction. Moreover, baicalein also overcame TRAIL resistance with DR5 up-regulation in prostate cancer PC3 cells. Of note, the combination of TRAIL and baicalein hardly induced apoptosis in normal human cells, such as blood cells and hepatocytes. Baicalein increased DR5 promoter activity, and this enhanced activity was diminished by mutation of a CCAAT/enhancer-binding protein homologous protein (CHOP)-binding site in SW480 cells. In SW480 cells, CHOP siRNA blocked both functions of baicalein. CHOP expression was induced by baicalein in SW480 cells; however, in PC3 cells, baicalein scarcely induced CHOP and mutation of the CHOP-binding site did not abrogate the DR5 promoter activation by baicalein. Interestingly, baicalein induced reactive oxygen species (ROS) and a ROS scavenger prevented DR5 expression and TRAIL sensitization in PC3 but not SW480 cells. These results indicate that, using two different pathways, baicalein exposes cancer surveillance of TRAIL and overcomes TRAIL resistance in cancer cells.
[Show abstract][Hide abstract] ABSTRACT: Kaempferol is a natural compound contained in edible plants, and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anti-cancer agent. Here, we show for the first time that the combined treatment with kaempferol and TRAIL drastically induced apoptosis in human colon cancer SW480 cells, compared to single treatments. Kaempferol markedly up-regulated TRAIL receptors, DR5 and DR4. DR5 but not DR4 siRNA efficiently blocked apoptosis induced by the co-treatment with kaempferol and TRAIL, indicating that DR5 up-regulation by kaempferol helps to enhance TRAIL actions. Moreover, we examined the combined effect on normal human cells. The co-treatment induced no apoptosis in normal human peripheral blood mononuclear cells and little apoptosis in normal human hepatocytes. These results suggest that kaempferol is useful for TRAIL-based treatments for cancer.
Full-text · Article · Nov 2008 · Biochemical and Biophysical Research Communications
[Show abstract][Hide abstract] ABSTRACT: Lipoxygenases induce malignant tumor progression and lipoxygenase inhibitors have been considered as promising anti-tumor agents. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is one of the most promising candidates for new cancer therapeutics. Combined treatment with nordihydroguaiaretic acid (NDGA), a lipoxygenase inhibitor, and TRAIL markedly induced apoptosis in Jurkat T-cell leukemia cells at suboptimal concentrations for each agent. The combined treatment efficiently activated caspase-3, -8 and -10, and Bid. The underling mechanism by which NDGA enhanced TRAIL-induced apoptosis was examined. NDGA did not change the expression levels of anti-apoptotic factors, Bcl-x(L), Bcl-2, cIAP-1, XIAP and survivin. The expression of death receptor-related genes was investigated and it was found that NDGA specifically up-regulated the expression of death receptor 5 (DR5) at mRNA and protein levels. Down-regulation of DR5 by small interfering RNA prevented the sensitizing effect of NDGA on TRAIL-induced apoptosis. Furthermore, NDGA sensitized prostate cancer and colorectal cancer cells to TRAIL-induced apoptosis. In contrast, NDGA neither enhanced TRAIL-induced apoptosis nor up-regulated DR5 expression in normal peripheral blood mononuclear cells. Another lipoxygenase inhibitor, AA861, also up-regulated DR5 and sensitized Jurkat and DU145 cells to TRAIL. These results indicate that lipoxygenase inhibitors augment the apoptotic efficiency of TRAIL through DR5 up-regulation in malignant tumor cells, and raise the possibility that the combination of lipoxygenase inhibitor and TRAIL is a promising strategy for malignant tumor treatment.