A PSMA-targeted theranostic agent for photodynamic therapy.

Prostate-specific membrane antigen (PSMA) is over-expressed in the epithelium of prostate cancer and in the neovasculature of many non-prostate solid tumors. PSMA has been increasingly used as a target for cancer imaging and therapy. Here we describe a low-molecular-weight theranostic photosensitizer, YC-9, for PSMA-targeted optical imaging and photodynamic therapy (PDT). YC-9 was synthesized by conjugating IRDye700DX N-hydroxysuccinimide (NHS) ester with a PSMA targeting Lys-Glu urea through a lysine-suberate linker in suitable yield. Optical imaging in vivo demonstrated PSMA-specific tumor uptake of YC-9 with rapid clearance from non-target tissues. PSMA-specific cell kill was demonstrated with YC-9in vitro through PDT in PSMA(+) PC3-PIP and PSMA(-) PC3-flu cells. In vivo PDT in mice bearing PSMA(+) PC3-PIP tumors at 4h post-injection of YC-9 (A total of four PDT sessions were performed, 48h apart) resulted in significant tumor growth delay, while tumors in control groups continued to grow. PDT with YC-9 significantly increased the median survival of the PSMA(+) PC3-PIP tumor mice (56.5days) compared to control groups [23.5-30.0days, including untreated, light alone, YC-9 alone (without light) and non-targeted IRDye700DX PDT treatment groups], without noticeable toxicity at the doses used. This study proves in principle that YC-9 is a promising therapeutic agent for targeted PDT of PSMA-expressing tissues, such as prostate tumors, and may also be useful against non-prostate tumors by virtue of neovascular PSMA expression.

Journal of photochemistry and photobiology. B, Biology. 2016 Dec 18 [Epub ahead of print]

Ying Chen, Samit Chatterjee, Ala Lisok, Il Minn, Mrudula Pullambhatla, Bryan Wharram, Yuchuan Wang, Jiefu Jin, Zaver M Bhujwalla, Sridhar Nimmagadda, Ronnie C Mease, Martin G Pomper

Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD 21287, United States. Electronic address: ., Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD 21287, United States., Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD 21287, United States. Electronic address: .