A tumor-targeted activatable phthalocyanine-tetrapeptide-doxorubicin conjugate for synergistic chemo-photodynamic therapy

Encapsulating pH‐Responsive Doxorubicin–Phthalocyanine Conjugates in Mesoporous Silica Nanoparticles for Combined Photodynamic Therapy and Controlled Chemotherapy

“…Apart from ab road Bband at 342 nm, aw eak vibronic band at 606 nm, and an intense and sharp Qband at 672 nm, aw eak absorption around 500 nm was also observed and attributed to the Doxm oiety. [21] Owing to the good spectralo verlap between the fluorescenceo fD ox and the absorption of ZnPc (Figure 1b), an efficient singlet-singlet energy transfer from the excited Dox to ZnPc was also observed. Upon excitation of the Dox moiety at 485 nm, only the fluorescenceo fZ nPc at 650-800 nm was seen, as observed by direct excitation of the ZnPc unit at 610 nm ( Figure 1c).…”

Pro-tumorigenic roles of fibroblast activation protein in cancer: back to the basics

“…Additional safety can be built in by requiring iterative activation events, as with an emitine-based prodrug which requires dual self-cleavage and FAP cleavage events in order to become active( 128 ). Heightened efficacy can be achieved by linking multiple drugs with a FAP-cleavable linker, as with a construct where doxycycline and light-activatable phthalocyanine inactivate each other until separated by FAP-mediated cleavage( 129 ). More sophisticated delivery methods designed to increase bioavailability to tumors include loading chemotherapeutics into nanoparticle carriers; in this case FAP can be used to activate the drugs( 130 ) or to help dissemble the carrier to mediate drug release and/or uptake( 131 , 132 ).…”

Porphyrin–peptide conjugates in biomedical applications

“…In the presence of FAP (in solution or in HepG2 cells) the conjugate released the free PS and drug leading to significant enhancement of fluorescence emission and photo‐cytotoxicity, suggesting a synergistic anticancer efficacy against HepG2 cells. The activation of the prodrug in vivo was confirmed by the fluorescence imaging of mice bearing a H22 murine hepatocellular tumor …”

“…Using a similar architecture, Ke et al developed a chemo‐photodynamic prodrug, that can be selectively activated in the tumor microenvironment. They linked together the PS (a zinc phthalocyanine) and the drug (doxorubicin) through a tetrapeptide sequence (TSGP) sensitive to the FAP protease expressed in tumor environments.…”