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.

Abstract. Renal cell carcinoma (RCC) is resistant to traditional cancer therapies such as radiation therapy and chemotherapy. The use of targeted therapies has improved the clinical outcomes of patients with metastatic RCC. However, most patients acquire resistance against targeted therapies over time. We report that the combination of the novel histone deacetylase (HDAC) inhibitor OBP-801, also known as YM753 and the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 synergistically inhibits cell growth and induces apoptosis in RCC cells. This combination activated caspase-3, -8 and -9 and the pan-caspase inhibitor zVAD-fmk significantly reduced the apoptotic response to the treatment with OBP-801 and LY294002. Moreover, the combined treatment induced intracellular reactive oxygen species (ROS) and the radical scavenger N-acetyl-L-cysteine (NAC) blocked the intracellular ROS and apoptosis induced by OBP-801 and LY294002. The co-treatment with OBP-801 and LY294002 markedly decreased survivin and the X-linked inhibitor of apoptosis protein (XIAP) protein levels, but Bcl-2 family members were not altered by the OBP-801/LY294002 co-treatment. These alterations were restored by NAC treatment. The transient transfection of survivin and XIAP reduced the apoptotic response to the OBP-801/LY294002 co-treatment. Additionally, OBP-801 was significantly more effective than SAHA, another HDAC inhibitor, in the combination with LY294002 against 786-O cells. Taken together, these results strongly suggest the combination of OBP-801 and LY294002 to be a promising treatment for RCC.

Abstract. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is endogenously expressed in immune cells and contributes to immunosurveillance for cancer. TRAIL induces apoptosis preferentially in various cancer cells, including renal cell carcinoma (RCC) cells. In this study, the serum TRAIL level was examined using an enzyme-linked immunosorbent assay in 52 healthy controls and in 84 RCC patients prior to surgery and its significance as a biomarker was evaluated. The median serum TRAIL level was lower in RCC patients compared to the healthy controls (55.9 vs. 103.1 pg/ml; P=0.019). RCC with lymph node metastasis (N1-2), distant metastasis (M1), stage III-IV, or microscopic venous invasion was associated with decreased serum TRAIL levels (P=0.032, 0.067, 0.020 and 0.011). When comparing serum TRAIL levels in the same RCC patients prior and subsequent to surgery (n=11), the levels were significantly higher after surgery (P=0.031). The cause-specific survival rate was significantly higher in RCC patients with high serum TRAIL levels compared to those with low serum TRAIL levels (P=0.0451). TRAIL was estimated to contribute 64 and 13% of the lymphocyte-mediated cytotoxicity against human RCC ACHN and Caki-1 cells, respectively. These data suggest that the serum TRAIL level may be useful as a prognostic biomarker in RCC patients.