塞来昔布与吉西他滨合用对胰腺癌的抑制作用及其机制

目的探讨环氧合酶2(COX2)选择性抑制剂塞来昔布和吉西他滨抑制胰腺癌生长的影响及其机制。方法观察塞来昔布与吉西他滨联合作用对裸鼠SW1990胰腺癌细胞移植瘤生长的影响,并与两者单独应用作比较,免疫组织化学染色观察肿瘤组织增殖细胞核抗原(PCNA)和细胞周期蛋白D1表达的变化;四唑蓝法、克隆形成试验观察塞来昔布和吉西他滨体外对SW1990细胞增殖的影响;流式细胞术检测细胞凋亡和细胞周期变化;Western印迹检测细胞周期蛋白D1、A和B1表达的变化。结果药物作用于裸鼠移植瘤32d后,对照组、吉西他滨组、塞来昔布组和联合组肿瘤体积分别为(2.31±0.41)cm3、(0.41±0.12)cm3、(1.56±0.17)cm3、(0.05±0.04)cm3,塞来昔布和吉西他滨联合可明显抑制胰腺癌移植瘤的生长,对照组PCNA、细胞周期蛋白D1呈强阳性表达,吉西他滨组PCNA、细胞周期蛋白D1阳性细胞数明显减少,塞来昔布组PCNA阳性细胞数较对照组略有减少,细胞周期蛋白D1阳性细胞数则无明显减少,而联合组中PCNA、细胞周期蛋白D1阳性细胞数较前3组明显减少。塞来昔布和吉西他滨剂量依赖性抑制SW1990细胞增殖,两药联合应用,对细胞增殖的抑制有增强作用。药物作用24h或72h后,塞来昔布组和联合组凋亡细胞数较对照组及吉西他滨组明显增加(P<0.05)。药物作用24h后,塞来昔布组和联合组G0/G1期细胞比例明显增加,G2/M期细胞明显减少,吉西他滨组G0/G1期细胞明显减少,而S期和G2/M期细胞明显增加,药物作用72h后,塞来昔布组和联合组G0/G1期细胞进一步增加,S期细胞明显减少,G2/M期细胞进一步减少,而联合组在作用24h和72h,G2/M期细胞比例均为0。细胞周期素的表达与细胞周期的分布相一致。结论COX2选择性抑制剂塞来昔布可增强吉西他滨对胰腺癌增殖的抑制作用,其机制可能部分通过调节细胞周期素的表达,诱导细胞周期阻滞和胰腺癌细胞凋亡而实现的。

Enhancing effects of celecoxib on the growth inhibition of pancreatic carcinoma by gemcitabine treatment

OBJECTIVE: To investigate the effect and the mechanisms of selective cyclooxygenase-2 (COX-2) inhibitor celecoxib in the growth inhibition of pancreatic cancer by gemcitabine. METHODS: Effects of gemcitabine combined with celecoxib on the proliferation in xenograft pancreatic carcinoma induced by SW1990 were investigated by immunohistochemistry of proliferating cell nuclear antigen (PCNA) and cyclin D1. Gemcitabine was administered intraperitoneally twice a week, and celecoxib was given via water daily. Effects of celecoxib and/or gemcitabine in pancreatic carcinoma cell SW1990 with different dose and time were investigated by MTT assay and soft agar assay. Effects on apoptosis and cell cycle were studied by flow cytometry. Effects on the protein expression of cyclin A, B(1) and D(1) were assessed by Western Blot. RESULTS: The mean volume of xenograft tumor was significantly reduced in gemcitabine group, celecoxib group and combination group (0.41 cm(3) +/- 0.12 cm(3), 1.56 cm(3) +/- 0.17 cm(3), 0.05 cm(3) +/- 0.04 cm(3) vs 2.31 cm(3) +/- 0.41 cm(3), P < 0.05). The expression of PCNA and cyclin D(1) was significantly reduced in gemcitabine group and can hardly be detected in combination group, but without significant change in celecoxib group. Celecoxib and gemcitabine inhibited pancreatic carcinoma cell growth dose-dependently, and the combination of celecoxib with gemcitabine inhibited cell growth to a greater degree than either compound alone. Apoptosis were induced in SW1990 by celecoxib alone or in combined with gemcitabine. Treatment with celecoxib only or combined with gemcitabine altered the cell cycle phase distribution in SW1990, cells were mainly arrested in G(0)/G(1) phase, S phase and G(2)/M phase development were greatly inhibited. Expression of Cyclin A, B(1) and D(1) were closely related with the cell cycle distribution induced by different drug. CONCLUSIONS: Selective COX-2 inhibitor celecoxib enhances the growth inhibition of pancreatic cancer induced by gemcitabine, which may be realized partly through the arrest of cell cycle and induction of cell apoptosis.