Modified Thymosin Alpha 1 Distributes and Inhibits the Growth of Lung Cancer in Vivo

[Image: see text] Targeted therapy of tumors is an effective method for treating cancer. Thymosin alpha 1 (Tα1), a hormone that contains 28 amino acids, is already approved for cancer treatment. However, its clinical application is limited because of the lack of tumor targeting. Considering that RGD can specifically bind to integrin, the anticancer drug can have a targeted therapeutic effect on tumors when it combines with a peptide containing an RGD sequence. We produced a polypeptide, Tα1-RGDR, by binding Tα1 to RGDR. The RGDR can combine with the αvβ3 and NRP-1 domains, which are highly expressed on the surface of the tumor, to achieve the effect of tumor targeting. This work aimed to investigate the difference of antitumor activity and tumor targeting between Tα1 modified by RGDR and Tα1 by using H460 and LLC tumor models. Results showed that Tα1-RGDR had remarkable antitumor effects, and its tumor targeting was better than that of Tα1. Hence, Tα1-RGDR is a promising antitumor drug.