Significance of serum tumor necrosis factor-related apoptosis-inducing ligand as a prognostic biomarker for renal cell carcinoma.

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.

Enhancement of the sensitivity of renal cell carcinoma cells to fas-mediated cytotoxicity and apoptosis by the selective cyclooxygenase-2 inhibitor JTE-522.

BACKGROUND: Cyclooxygenase-2 (COX-2) is a key enzyme involved in the production of prostaglandins and its inhibitors have been shown to induce apoptosis in a variety of cancer cells. We reasoned that combination treatment of renal cell carcinoma (RCC) cells with COX-2 inhibitors and anticancer agents may result in synergistic apoptosis. We examined whether the selective COX-2 inhibitor JTE-522 synergizes with anticancer agents in cytotoxicity and apoptosis against RCC cells. METHODS: The cytotoxicity of the selective COX-2 inhibitor JTE-522 and other anticancer agents against the RCC cell lines and the normal renal cell line was determined by the microculture tetrazolium dye assay. RESULTS: JTE-522 was cytotoxic against the Caki-1 RCC cell line. JTE-522 and anti-Fas monoclonal antibody (CH-11) exhibited a synergistic cytotoxic effect against Caki-1 cells. In contrast, JTE-522 in combination with 5-fluorouracil, adriamycin, cis-diamminedichloroplatinum, or interferon-alpha, all commonly used clinically, resulted in an additive cytotoxic effect. Synergy achieved in cytotoxicity with JTE-522 and CH-11 was shown to be due to apoptosis. CONCLUSIONS: The present study demonstrated that the selective COX-2 inhibitor JTE-522 had a cytotoxic effect on RCC and that synergistic cytotoxicity against RCC was obtained with JTE-522 in combination with anti-Fas monoclonal antibody. These results suggest that selective COX-2 inhibitors in combination with immunotherapy may be useful in treating patients with RCC.

Significant antitumor activity of cationic multilamellar liposomes containing human interferon-beta gene in combination with 5-fluorouracil against human renal cell carcinoma.

Immunotherapy is one of the most effective treatments against metastatic renal cell carcinoma (RCC). However, the response rate is not high. Therefore, more effective therapies are necessary for patients with metastatic RCC. We previously reported on the significant antitumor activity of cationic multilamellar liposome containing human interferon-beta (huIFN-beta) gene (IAB-1) against RCC. We then examined the antitumor effect of IAB-1 in combination with anticancer drugs against RCC. The cytotoxicity of IAB-1 alone, and in combination with anticancer drugs, cisplatin, adriamycin, 5-fluorouracil, gemcitabine, paclitaxel and irinotecan hydrochloride against the human RCC cell line NC65 was examined by the colorimetric method using tetrazolium salt. For the in vivo study, we used NC65 cells inoculated into the severe combined immunodeficiency mouse. The results showed that the in vitro combination therapy with IAB-1 and 5-FU was more cytotoxic than IAB-1 alone. However, synergistic cytotoxicity was not observed when combined with IAB-1 and other anticancer drugs. NC65 tumors transfected with IAB-1 in mice were smaller than those receiving an injection of empty liposome or the recombinant huIFN-beta protein. Treatment with IAB-1 in combination with 5-FU resulted in significant anticancer activity. IAB-1 enhanced the activity of thymidine phosphorylase (TP), which converts 5-FU to the active metabolite, FdUMP. In contrast, IAB-1 decreased the activity of thymidylate synthase (TS), which is a target enzyme of 5-FU. In conclusion, these findings indicate that a combination of IAB-1 and 5-FU may have enhanced antitumor activity against human RCC, suggesting its potential clinical application. The mechanism of enhanced cytotoxicity by combination therapy with IAB-1 and 5-FU may up-regulate TP activity and down-regulate TS activity.