cAMP诱导膀胱肿瘤细胞分化的研究

Differentiation of bladder cancer cells induced by cAMP

目的：探讨ｃＡＭＰ诱导膀胱肿瘤细胞分化的作用。方法：野生型膀胱肿瘤细胞Ｔ２４作为对照细胞，实验组细胞分别用１０μｍｏｌ／Ｌ和４０μｍｏｌ／Ｌ的ｃＡＭＰ诱导培养２８ｄ，观察对照细胞和实验细胞的增殖率、裸鼠致瘤率，流式细胞仪测定ｐ２１、ｐ６５蛋白表达率、电子显微镜观察细胞超微结构变化。结果：对照细胞增殖率、ｐ２１、ｐ６５表达率、裸鼠致瘤率均为１００％。实验组细胞经１０μｍｏｌ／Ｌ和４０μｍｏｌ／Ｌ的８－Ｂｒ－ｃＡＭＰ诱导１４、２１、２８ｄ，增殖率分别降为９２．４、７３．６、５７．１、９０．８、６４．２、４９．９％；１０μｍｏｌ／Ｌ和４０μｍｏｌ／Ｌ的ｃＡＭＰ诱导２８ｄ后，ｐ２１表达率分别降为６３％和５８％，ｐ６５表达率降为５４％和４９％，裸鼠致瘤率降为６０％和４０％；超微结构显示细胞恶性表型下降。结论：ｃＡＭＰ通过下调ｒａｓ和ｍｙｃ基因表达而诱导分化、抑制肿瘤恶性表型，这一作用在肿瘤的预防和治疗中具有重要意义。

Objective: To explore the inductive effects of cAMP on differentiation of bladder cancer cells. Methods: Wild type bladder cancer cell T24 was employed to serve as the control. The cells in the experimental group was respectively cultured with 10 μmol/L and 40 μmol/L of 8BrcAMP for 28 days. The proliferative rate and tumorigenic rate in nude mice were determined, the expressive rate of p21 and p65 protein measured with cytometry and the ultrastructural changes of all the cells observed with electron microscopy. Results: In the control group, the expressive rate of p21 and p65 protein and the proliferative rate and tumorigenic rate in nude mice of the cells were all 100%. In the experimental group, the proliferative rate of the cells were decreased to 92.4%, 73.6% and 57.1% and 90.8%, 64.2% and 49.9% in the 14th, 21th and 28th day after induction in 10 μmol/L and 40 μmol/L cAMP-induced cells respectively. In the 28th day after induction, the expressive rate of p21 was decreased to 63% and 58%, the expressive rate of p65 to 54% and 49% and the tumorigenic rate to nude mice to 60% and 40% in the cells induced by 10 μmol/L and 40 μmol/L cAMP respectively. Morphological observation showed that the malignant phenotype was inhibited. Conclusion: cAMP induces differentiation and inhibits the malignant phenotype of bladder cancer cells through downregulation of the expression of ras and myc genes, which is important for prevention and treatment of tumor.