转化生长因子α联结saporin对平滑肌细胞和内皮细胞具有选择性的细胞毒作用

目的　为证实生物导向药物TGFα SAP对增殖平滑肌细胞特异性的细胞毒性作用。方法　我们用SPDP化学联结法合成了TGFα SAP ,并用3 H TdR参入法和3 H Leucine参入法探讨了TGFα SAP对平滑肌细胞及内皮细胞的DNA合成及蛋白质合成的影响。结果　联结后的TGFα SAP对增殖平滑肌细胞的3 H TdR参入量有明显抑制作用 ,与空白对照组比较3 H TdR参入量降低了 4 4 0 % ,同时TGFα SAP亦可明显抑制平滑肌细胞的蛋白质合成 ,而saporin本身显示出的细胞毒性作用则很弱。相反 ,TGFα SAP对增殖的内皮细胞的DNA和蛋白质合成却未显示出明显的抑制作用。结论　TGFα SAP具有较saporin明显增强的细胞毒性作用 ,而与内皮细胞相比 ,TGFα SAP对增殖平滑肌细胞表现出明显受体选择的特异性抑制作用

Transforming growth factor-α conjugated with cytotoxin saporin inhibits specifically proliferating vascular smooth muscle cells

AIM To testify the special cytotoxicity of TGFα SAP on proliferating vascular smooth muscle cells and endothelial cells. METHODS Conjugation of saporin to TGFα was accomplished after derivatization of saporin and TGFα with N succinimidyl 3 (2 pyridyldithio) proprionate. Cytotoxicity assays were measured by cell count. The studies of influence of TGFα SAP on values of thymidine and leucine incorporation into SMCs and ECs were measured by 3H thymidine uptake and 3H leucine uptake, respectively. RESULTS Cytotoxicity assays testified TGFα SAP conjugate could inhibit remarkably proliferation of SMCs in culture. The values of thymidine of TGFα SAP group (1×10 -9 mol·L -1 and 1×10 -7 mol·L -1 ) in comparison significantly decreased to 60 9% and 56 0% of the control group respectively, suggesting that cellular DNA synthesis obviously decreased as TGFα SAP was added. But saporin did not affect cellular DNA synthesis at higher level. The rate of 3H leucine incorporation of TGFα SAP group significantly decreased to 47 3% of the control group, suggesting that SMCs protein synthesis obviously decreased as TGFα SAP was added. But TGFα SAP at the same level did not affect DNA synthesis and protein synthesis of ECs compared with the control group. CONCLUSION TGFα SAP possesses the more effective cytotoxicity than saporin and the more specific citotoxicity on proliferating vascular smooth muscle cells than on proliferating endothelial cells.