表皮生长因子联合吉西他滨作用裸鼠后的残存肿瘤细胞研究

Remaining tumour cells after combined effect of epidermal growth factor and gemcitabine for bladder cancer xenografted tumor

目的观察表皮生长因子(EGF)联合吉西他滨(GEM)对膀胱癌裸鼠移植瘤的作用,探讨其机制及残存细胞的特性。方法建立裸鼠膀胱癌BIU-87细胞的移植瘤模型,观察EGF联合GEM组及化疗组BIU-87细胞株的成瘤能力和抑制率,检测细胞核增殖抗原(Ki-67)、主要周期蛋白(Cyclin A、Cyclin B、Cyclin D、Cyclin E)的表达、CD44+细胞比例和残存细胞的成瘤能力。结果EGF联合GEM组肿瘤抑制率明显高于GEM组,分别为70.7%与40.0%(P<0.05),EGF联合GEM组Ki-67表达高于GEM化疗组[(52.76±6.36)%比(37.01±4.45)%,P<0.05],联合组主要周期蛋白Cyclin A、Cyclin B、Cyclin D、Cyclin E表达低于化疗组[(33.76±4.94)%比(53.67±5.37)%、(31.26±4.67)%比(49.46±5.35)%、(31.85±5.56)%比(54.58±7.67)%、(43.01±6.45)%比(66.45±7.09)%,P<0.05]。联合治疗组膀胱癌干细胞标志物CD44+的细胞比例明显高于化疗组[(9.12±0.49)%比(5.39±0.32)%, P<0.05],联合治疗组残存细胞成瘤能力明显增强[成瘤体积(1 731.24±110.34) mm^3比(2 298.84±102.56) mm^3,P<0.05]。结论EGF可增强GEM对膀胱癌细胞的敏感性,其机制可能与EGF诱导静止期膀胱癌细胞增殖相关,联合组残存细胞为一群低Cyclins的肿瘤细胞亚群,该细胞亚群成瘤能力更强。

Objective To study the combined effect of epidermal growth factor (EGF) and Gemcitabine (GEM) for bladder cancer xenografted tumor, preliminary mechanism of action, and character of the remaining tumour cell. Methods Bladder cancer xenografted tumor model was established. Treated by united therapy group and merely chemotherapy group, the bladder cancer BIU-87 cells were tested for the ability to form tumors, tumor control rate, the expression of proliferation cell nuclear antigen (Ki-67), Cyclins (Cyclin A, Cyclin B, Cyclin D, Cyclin E), the CD44+ positive proportion in bladder cancer cells, and tumorigenic ability. Results Tumor control rate of bladder cancer xenografted tumor in EGF+ GEM group was apparently higher than that in GEM group, respectively 70.7% and 40%(P<0.05). The expression of Ki-67 in EGF+ GEM group and GEM group were respectively (52.76±6.36)% and (37.01±4.45)%(P<0.05). The expression level of Cyclins (Cyclin A, Cyclin B, Cyclin D, Cyclin E) of bladder cancer xenografted tumor in EGF+ GEM group were apparently lower than these in GEM group, respectively (33.76±4.94)%,(53.67±5.37)%;(31.26±4.67)%,(49.46±5.35)%;(31.85±5.56)%,(54.58±7.67)%;(43.01±6.45)%,(66.45±7.09)%(P<0.05). The CD44+ positive proportion of bladder cancer xenografted tumor in EGF+ GEM group were apparently higher than these in chemotherapy group, respectively (9.12±0.49)% and (5.39±0.32)%(P<0.05). Tumorigenic ability of the remaining tumour cells in EGF+ GEM group were apparently higher than these in GEM group,(1 731.24±110.34),(2 298.84±102.56) mm^3 (P<0.05). Conclusion EGF can enhance the sensitivity of GEM to bladder cancer cells, and the possible mechanism is that EGF induces these bladder cancer cells in stationary phase into cell proliferative phase. The remaining tumor cells treated by EGF+ GEM may be new tumor cell subpopulation with low Cyclins and stronger tumorigenic ability.