3-(4'-Hydroxyphenyl)propionic acid-OSu

We designed and synthesized 131I-labeled dendrimers modified with the LyP-1 peptide as a multifunctional platform for single-photon emission computed tomography (SPECT) imaging, radionuclide therapy, and antimetastasis therapy of cancer. The multifunctional platform was constructed by modifying amine-terminated generation 5 poly(amidoamine) dendrimers with 33.1 LyP-1 peptide and 9.2 3-(4'-hydroxyphenyl)propionic acid-OSu (HPAO), followed by acetylation of the remaining dendrimer terminal amines and radiolabeling with 131I via the HPAO moieties. The LyP-1-modified dendrimers showed favorable cytocompatibility in the studied concentration range of 0.1-10 μM for 24 h and could be labeled by 131I with satisfactory radiochemical purity (>99%) and stability (>90% even at 16 h). The 131I-labeled LyP-1-modified dendrimers were capable of being utilized as a diagnostic probe for SPECT imaging and as a therapeutic agent for radionuclide therapy and antimetastasis of cancer cells in vitro and in a subcutaneous tumor model in vivo. Based on analyses of the tumor microenvironment, the antitumor and antimetastasis effects could be because of the reduced levels of the molecular markers associated with proliferation and metastasis, improved local hypoxia, and increased apoptosis rate. The developed 131I-labeled dendrimeric nanodevice may hold great promise to be used as a nanotheranostic platform for cancer diagnosis and therapy.

Background: The development of alternative anti-angiogenesis therapy for choroidal neovascularization (CNV) remains a great challenge. Nanoparticle systems have emerged as a new form of drug delivery in ocular diseases. Here, we report the construction and characterization of arginine-glycine-aspartic acid (RGD)-conjugated polyethyleneimine (PEI) as a vehicle to load antioxidant salvianolic acid A (SAA) for targeted anti-angiogenesis therapy of CNV. In this study, PEI was consecutively modified with polyethylene glycol (PEG) conjugated RGD segments, 3-(4'-hydroxyphenyl) propionic acid-Osu (HPAO), and fluorescein isothiocyanate (FI), followed by acetylation of the remaining PEI surface amines to generate the multifunctional PEI vehicle PEI.NHAc-FI-HPAO-(PEG-RGD) (for short, RGD-PEI). The formed RGD-PEI was utilized as an effective vehicle platform to load SAA. Results: We showed that RGD-PEI/SAA complexes displayed desirable water dispersibility, low cytotoxicity, and sustainable release of SAA under different pH conditions. It could be specifically taken up by retinal pigment epithelium (RPE) cells which highly expressed ɑvβ5 integrin receptors in vitro and selectively accumulated in CNV lesions in vivo. Moreover, the complexes displayed specific therapeutic efficacy in a mouse model of laser induced CNV, and the slow elimination of the complexes in the vitreous cavity was verified by SPECT imaging after 131I radiolabeling. The histological examinations further confirmed the biocompatibility of RGD-PEI/SAA. Conclusions: The results suggest that the designed RGD-PEI/SAA complexes may be a potential alternative anti-angiogenesis therapy for posterior ocular neovascular diseases.

Design of theranostic nanoplatforms represents a major topic for current nanomedicine. Here, the preparation of multifunctional poly(cyclotriphosphazene-co-polyethylenimine) nanospheres (PNSs) labeled with radionuclide 131 I for single photon emission computed tomography (SPECT) imaging-guided radiotherapy of tumors is reported. In this work, PNSs are prepared using hexachlorocyclotriphosphazene as a crosslinker to crosslink branched polyethylenimine (PEI) via a nucleophilic substitution reaction, modified with 3-(4'-hydroxyphenyl) propionic acid-OSu (HPAO) for 131 I labeling, and reacted with 1,3-propane sulfonate (1,3-PS) to render the particles with antifouling property, followed by acetylation of the remaining surface amines and labeling with 131 I. The acquired PNS.NHAc-HPAO(131 I)-PS particles are well characterized. It is shown that the multifunctional PNSs with an average size of 184 ± 29.3 nm exhibit favorable antifouling properties, high 131 I labeling efficiency (76.05 ± 3.75%), and excellent radiostability and colloidal stability. With these properties owned, the developed PNS.NHAc-HPAO(131 I)-PS spheres enable much more efficient SPECT imaging and radiotherapy of a xenografted tumor model in vivo than the PEI counterpart material (PEI.NHAc-HPAO(131 I)-PS). The developed PNSs may be used as a versatile platform for further development of different forms of nanomedicine for various biomedical applications.