Department of Oral and Maxillofacial Surgery, Nanfang Hospital, Southern Medical University, 1838 North Guangzhou Road, Guangzhou 510515, China.
Prostaglandins Other Lipid Mediat. 2012 Jan;97(1-2):29-35. doi: 10.1016/j.prostaglandins.2011.07.007. Epub 2011 Aug 3.
Previous studies have indicated that long-term chemotherapy decreases the sensitivity of oral cancer cells to chemotherapeutics while simultaneously increasing resistance to these drugs. COX-2 inhibitors are known to enhance the toxic action of anti-tumor drugs against cancer cells. Using the MTT method, we investigated the influence of the COX-2 selective inhibitor Celecoxib on the proliferation of KB/VCR oral cancer cell lines and analyzed the effect of Celecoxib on the regulation of P-glycoprotein (P-gp) expression and function. Western blot analysis was employed to detect the expression of P-gp, and flow cytometry was used to evaluate P-gp function by detecting the accumulation of the active P-gp functional fluorescence substrate within KB/VCR cells. The results revealed that a low dose of Celecoxib (10 μmol/L) showed no growth inhibitory effects on KB/VCR cell lines. When the concentration of Celecoxib was greater than or equal to 20 μmol/L, the inhibitory effect on KB/VCR cells was significantly enhanced in a time- and dose-dependent manner. The lower dose of Celecoxib (10 μmol/L) significantly enhanced the toxicity of Vincristine (VCR) against KB/VCR cell lines. After the application of Celecoxib plus VCR (10 μmol/L+1.5μmol/L, respectively) treatment for 24, 48 or 72 h, the growth inhibition rates of KB/KBV cells were 37.82 ± 1.60%, 47.84 ± 1.29% and 54.43 ± 2.35%, respectively, which were significantly higher than the rates in the cells treated only with Celecoxib (10 μmol/L) or VCR (1.5 μmol/L) (all P<0.01). P-gp expression levels in KB/KBV cells treated with Celecoxib plus VCR (10 μmol/L+1.5 μmol/L, respectively) were markedly lower than the levels in control cells and those treated with VCR (1.5 μmol/L) (all P<0.01). In addition, the intensity of Rho123 fluorescence of KB/KBV cells in cells treated with Celecoxib plus VCR (10 μmol/L+1.5 μmol/L, respectively) or Celecoxib alone (10 μmol/L) was significantly higher than the intensity observed in control cells and those treated with VCR alone (1.5 μmol/L) (all P<0.01). The underlying mechanism of these phenomena is likely correlated with the down-regulation of the expression and function of P-gp due to Celecoxib, thereby increasing the amount of VCR accumulated in KB/VCR cells.
先前的研究表明，长期化疗会降低口腔癌细胞对化疗药物的敏感性，同时增加其耐药性。COX-2 抑制剂已知可增强抗肿瘤药物对癌细胞的毒性作用。我们采用 MTT 法，研究了 COX-2 选择性抑制剂塞来昔布对 KB/VCR 口腔癌细胞系增殖的影响，并分析了塞来昔布对 P-糖蛋白（P-gp）表达和功能调节的影响。采用 Western blot 分析检测 P-gp 的表达，采用流式细胞术检测 KB/VCR 细胞内活性 P-gp 功能荧光底物的积累，以评估 P-gp 功能。结果表明，低剂量塞来昔布（10μmol/L）对 KB/VCR 细胞系无生长抑制作用。当塞来昔布浓度≥20μmol/L 时，对 KB/VCR 细胞的抑制作用呈时间和剂量依赖性显著增强。低剂量塞来昔布（10μmol/L）显著增强了长春新碱（VCR）对 KB/VCR 细胞系的毒性。分别用塞来昔布加长春新碱（10μmol/L+1.5μmol/L）处理 24、48 或 72 h 后，KB/KBV 细胞的生长抑制率分别为 37.82±1.60%、47.84±1.29%和 54.43±2.35%，明显高于单独用塞来昔布（10μmol/L）或长春新碱（1.5μmol/L）处理的细胞（均 P<0.01）。用塞来昔布加长春新碱（10μmol/L+1.5μmol/L）处理的 KB/KBV 细胞中 P-gp 的表达水平明显低于对照组细胞和单独用长春新碱（1.5μmol/L）处理的细胞（均 P<0.01）。此外，用塞来昔布加长春新碱（10μmol/L+1.5μmol/L）或塞来昔布（10μmol/L）处理的 KB/KBV 细胞中 Rho123 荧光强度明显高于对照组细胞和单独用长春新碱（1.5μmol/L）处理的细胞（均 P<0.01）。这些现象的潜在机制可能与塞来昔布下调 P-gp 的表达和功能有关，从而增加 KB/VCR 细胞中长春新碱的蓄积量。
