Cytotoxic Effects of Transforming Growth Factor-α Conjugated with Cytotoxin Saporin on proliferating vascular smooth muscle cells

摘要

Objective: 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 and final purification of the conjugate was achieved within Eppendorf Centrifugal Filter 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. and receptor competition studies of TGFα-SAP are measured by adding excess TGFα in SMCs exposed for TGFα-SAP. Results: Cytotoxicity assays testified TGFα-SAP conjugate could inhibit remarkably proliferation of SMCs in culture. The values of thymidine of TGFα-SAP group (10~(-9)M and 10~(-7)M) 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: The results indicated that TGFα-SAP possesses the more effective cytotoxicity than Saporin and the more special citotoxicity on proliferating vascular smooth muscle cells than on proliferating endothelial cells.