Yong Nan Li

Kyoto Prefectural University of Medicine, Kyoto, Kyoto-fu, Japan

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Publications (6)35.05 Total impact

  • Article: Enhancement of the sensitivity of renal cell carcinoma cells to fas-mediated cytotoxicity and apoptosis by the selective cyclooxygenase-2 inhibitor JTE-522.
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    ABSTRACT: 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. 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. 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. 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.
    Urologia Internationalis 01/2010; 84(3):362-8. · 0.99 Impact Factor
  • Article: Overexpression of XIAP expression in renal cell carcinoma predicts a worse prognosis.
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    ABSTRACT: X-linked inhibitor of apoptosis protein (XIAP) is the most potent caspase-inhibitory IAP family member and a negative regulator of various apoptotic stimuli. Thus, XIAP overexpression in cancer cells may select for tumor cell survival following various cytotoxic therapeutic modalities. The anatomical staging system in renal cell carcinoma (RCC) currently provides good prognostic information, albeit insufficient. We hypothesize that overexpression of XIAP in RCC may serve as a molecular prognostic marker in RCC and improve the staging of RCC. This study examined the protein level of XIAP in lysates from surgical specimens of 109 patients with RCC and 109 normal kidney specimens from the same patients. The level of XIAP expression was quantified by Western blot analysis using non-fixed fresh frozen tissues of RCCs and normal kidneys. Results indicated that the mean level of XIAP expression was higher in RCC compared to autologous normal kidney, and the XIAP expression level in 38/109 (35%) of RCC was more than 2-fold greater than that in normal kidney tissue. In Stage I/II RCC, the mean XIAP expression level was almost identical to that detected in normal kidney, whereas XIAP expression in Stage III/IV was 2.5-fold higher than that in Stage I/II RCC. Levels of XIAP expression also correlated with the grade of RCC. Patients with RCC with low XIAP expression had a longer postoperative disease-specific survival as compared to those with high expression in the 5-year follow-up. The suggested role of XIAP in the regulation of resistance in apoptosis was examined in vitro following treatment of RCC cell lines with XIAP antisense oligonucleotide and the cells were sensitized to both Fas-mediated and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. The present study demonstrates at the protein level that XIAP is overexpressed in RCC, and that high XIAP expression in RCC predicted a worse prognosis. In addition, XIAP antisense oligonucleotide sensitized RCC to Fas/TRAIL-induced apoptosis. These results suggest that XIAP expression in RCC may be used as a prognostic parameter, and that downregulation or inhibition of XIAP expression in RCC may reverse immune resistance.
    International Journal of Oncology 05/2007; 30(4):919-25. · 2.40 Impact Factor
  • Article: Downregulation of Smac/DIABLO expression in renal cell carcinoma and its prognostic significance.
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    ABSTRACT: Second mitochondria-derived activator of caspase/direct inhibitor of apoptosis-binding protein with low pI (Smac/DIABLO) was recently identified as a protein that is released from mitochondria in response to apoptotic stimuli and promotes apoptosis by antagonizing inhibitor of apoptosis proteins. Furthermore, Smac/DIABLO plays an important regulatory role in the sensitization of cancer cells to both immune- and drug-induced apoptosis. However, little is known about the clinical significance of Smac/DIABLO in various cancers, including renal cell carcinoma (RCC). This study examined Smac/DIABLO expression in 78 healthy kidneys and 78 RCCs. The level of Smac/DIABLO expression was quantified by Western blot analysis using nonfixed fresh frozen tissues. The expression of Smac/DIABLO was lower in RCC compared with the autologous normal kidney. Sixty-four (82%) of 78 of RCC expressed Smac/DIABLO, and 18% were negative, whereas 100% of normal kidney tissues were positive. In stage I/II RCC, 96% expressed Smac/DIABLO, whereas only 50% expressed Smac/DIABLO in stage III/IV. Smac/DIABLO expression inversely correlated with the grade of RCC. Patients with RCC expressing Smac/DIABLO had a longer postoperative disease-specific survival than those without Smac/DIABLO expression in the 5-year follow-up. Transfection with Smac/DIABLO cDNA enhanced tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) -mediated and cisplatin-mediated cytotoxicity in RCC. The present study demonstrates for the first time that Smac/DIABLO expression was downregulated in RCC and that no Smac/DIABLO expression in RCC predicted a worse prognosis. In addition, transfection with Smac/DIABLO sensitized RCC to TRAIL/cisplatin-induced apoptosis. These results suggest that Smac/DIABLO expression in RCC may be used as a prognostic parameter, and that enhancement of Smac/DIABLO expression in RCC may potentiate immunotherapy and chemotherapy.
    Journal of Clinical Oncology 02/2005; 23(3):448-54. · 18.37 Impact Factor
  • Article: Prognostic significance of serum osteoprotegerin levels in patients with bladder carcinoma.
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    ABSTRACT: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) plays an important role in the process of lymphocyte-mediated cytotoxicity against malignant cells. Osteoprotegerin (OPG) is a soluble decoy receptor for TRAIL, and circulating OPG has been implicated in the protection of cells from TRAIL-mediated apoptosis. Thus, OPG may protect tumor cells from lymphocyte-mediated cytotoxicity and, as a result, contribute to tumor progression. In the current study, the authors investigated this hypothesis in patients with bladder carcinoma. Serum OPG levels for 185 patients with bladder carcinoma were determined using an enzyme-linked immunosorbent assay. These levels then were assessed for potential correlations with various disease characteristics and outcome measures. The mean serum OPG concentration in patients with bladder carcinoma was approximately 3 times greater than the mean concentration in healthy individuals, and among patients with bladder carcinoma, higher tumor stage and grade were found to be associated with increased serum OPG levels. Within the subpopulation of patients with superficial bladder carcinoma, after a follow-up period of 5 years, those who had low serum OPG levels tended to have a longer postoperative tumor-free interval compared with those who had high serum OPG levels. Furthermore, among patients with muscle-invasive bladder carcinoma, the 5-year disease-specific survival rate was greater for those who had low serum OPG levels than for those who had high serum OPG levels. To the authors' knowledge, the current study is the first to demonstrate that serum OPG concentration is correlated with both tumor stage and tumor grade and that elevated serum OPG levels are predictive of early recurrence in patients with bladder carcinoma. These findings suggest that serum OPG concentration may have utility as a prognostic parameter in this setting.
    Cancer 11/2004; 101(8):1794-802. · 4.77 Impact Factor
  • Article: Enhanced sensitivity of bladder cancer cells to cisplatin mediated cytotoxicity and apoptosis in vitro and in vivo by the selective cyclooxygenase-2 inhibitor JTE-522.
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    ABSTRACT: Cyclooxygenase-2 (COX-2) is a key inducible enzyme involved in the production of prostaglandins and its inhibitors have been shown to induce apoptosis in various cancer cells. Several anticancer agents also mediate apoptosis and may share the common intracellular pathways leading to apoptosis with COX-2 inhibitors. We reasoned that combination treatment of bladder cancer cells with COX-2 inhibitors and anticancer agents may result in synergistic apoptosis. We examined whether the selective COX-2 inhibitor JTE-522 (4-(4-cyclohexyl-2-methyloxazol-5-yl)-2-fluorobenzenesulfonamide) synergizes with anticancer agents in cytotoxicity and apoptosis against bladder cancer cells in vitro and in vivo. Cytotoxicity was determined by the microculture tetrazolium dye assay. Combination treatment of T24 bladder cancer cells with JTE-522 and cis-diamminedichloroplatinum (II) (CDDP) resulted in a synergistic cytotoxic effect. Synergy achieved in cytotoxicity with JTE-522 and CDDP was shown to be due to apoptosis. Treatment of T24 cells with JTE-522 decreased expression of the anti-apoptotic molecule Bcl-2. The in vivo significant growth inhibitory effect of JTE-522 and CDDP against the T24 line heterotransplanted in SCID mice was also observed. This study demonstrates that combination treatment of bladder cancer cells with the selective COX-2 inhibitor JTE-522 and CDDP results in synergistic cytotoxicity and apoptosis in vitro and in vivo. These findings support the potential clinical application of a combination of JTE-522 and CDDP for the treatment of bladder cancer as a new form of therapy with more selective cytotoxicity and fewer collateral side effects.
    The Journal of Urology 11/2004; 172(4 Pt 1):1474-9. · 3.75 Impact Factor
  • Article: Prognostic significance of orotate phosphoribosyltransferase activity in bladder carcinoma.
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    ABSTRACT: 5-Fluorouracil (5-FU), an antitumor agent, is used clinically against a variety of malignancies, including bladder carcinoma. 5-FU is a prodrug, and orotate phosphoribosyltransferase (OPRT) is the principal enzyme that converts 5-FU directly into an active antitumor metabolite, 5-fluoro-2'-deoxyuridine 5'-monophosphate. In addition, OPRT is the key enzyme in the de novo DNA and RNA synthetic process. To the authors' knowledge, little is known regarding the significance of OPRT in various malignancies, including bladder carcinoma. The authors analyzed the activity levels of OPRT in 60 bladder carcinomas and evaluated the association between the level of OPRT activity and the stage and grade status of bladder carcinoma. They also examined the prognostic significance of OPRT activity in patients with bladder carcinoma and the correlation between OPRT activity levels in bladder carcinoma cells and the sensitivity of those cells to 5-FU. OPRT activity levels in nonfixed, fresh-frozen specimens of bladder carcinoma and normal bladder were determined enzymatically using a 5-FU phosphorylation assay. The sensitivity of bladder cells to 5-FU was assessed using a microculture tetrazolium dye assay. The activity levels of OPRT were approximately 7.5-fold higher in bladder carcinoma specimens compared with the activity levels in normal bladder specimens. OPRT activity in muscle-invasive bladder carcinoma was 2-fold higher compared with the activity in superficial bladder carcinoma (classified as Ta and T1). In addition, the activity of OPRT in T1 bladder carcinoma was 2-fold higher compared with the activity in Ta bladder carcinoma. The level of OPRT activity in Grade 3 bladder carcinoma was 6-fold and 2-fold higher compared with the activity in Grade 1 and Grade 2 bladder carcinoma, respectively. Patients who had Ta and T1 bladder carcinoma with low OPRT activity had a longer postoperative tumor free period compared with patients who had bladder carcinoma with high OPRT activity in the 3-year follow-up. There was a positive association between the activity levels of OPRT and thymidylate synthase/thymidine kinase, which are the key enzymes in the de novo/salvage DNA synthetic process. OPRT activity in bladder carcinoma cells was correlated positively with their sensitivity to 5-FU. to the authors' knowledge, the current study is the first to demonstrate that OPRT activity levels in bladder carcinoma were higher compared with its activity in the normal bladder tissues and that OPRT activity levels were correlated positively with the stage and grade of bladder carcinoma. In addition, high OPRT activity levels in patients with superficial bladder carcinoma predicted early recurrence and high sensitivity to 5-FU. These results suggest that the level of OPRT activity may be used both as a prognostic parameter and as a predictive indicator for 5-FU efficacy in patients with bladder carcinoma and that OPRT may be a molecular therapeutic target in bladder carcinoma.
    Cancer 03/2004; 100(4):723-31. · 4.77 Impact Factor