GX1-conjugated poly(lactic acid) nanoparticles encapsulating endostar for improved in vivo anticolorectal cancer treatment

Tumor angiogenesis plays a key role in tumor growth and metastasis; thus, targeting tumor-associated angiogenesis is an important goal in cancer therapy. However, the effcient delivery of drugs to tumors remains a key issue in antiangiogenesis therapy. GX1, a peptide identifed by phage-display technology, is a novel tumor vasculature endothelium-specifc ligand and possesses great potential as a targeted vector and antiangiogenic agent in the diagnosis and treatment of human cancers. Endostar, a novel recombinant human endostatin, has been shown to inhibit tumor angiogenesis. In this study, we developed a theranostic agent composed of GX1-conjugated poly(lactic acid) nanoparticles encapsulating Endostar (GPENs) and labeled with the near-infrared dye IRDye 800CW to improve colorectal tumor targeting and treatment effcacy in vivo. The in vivo fuorescence molecular imaging data showed that GPENs (IRDye 800CW) more specifcally targeted tumors than free IRDye 800CW in colorec-tal tumor-bearing mice. Moreover, the antitumor effcacy was evaluated by bioluminescence imaging and immunohistology, revealing that GPENs possessed improved antitumor effcacy on subcutaneous colorectal xenografts compared to other treatment groups. Thus, our study showed that GPENs, a novel GX1 peptide guided form of nanoscale Endostar, can be used as a theranostic agent to facilitate more effcient targeted therapy and enable real-time monitoring of therapeutic effcacy in vivo.