Synthesis and evaluation of radiolabeled porphyrin derivatives for cancer diagnoses and their nonradioactive counterparts for photodynamic therapy

Abstract

Radioiodinated porphyrin derivatives and the corresponding nonradioactive iodine introduced compounds, [¹²⁵I]I-TPP_OH ([¹²⁵I]3), [¹²⁵I]I-l-tyrosine-TPP ([¹²⁵I]9), I-TPP_OH (3), and I-l-tyrosine-TPP (9) were designed, synthesized, and evaluated by <i>in vitro</i> and <i>in vivo</i> experiments. In cytotoxicity assays, 3 and 9 exhibited significant cytotoxicity under light conditions but did not show significant cytotoxicity without light irradiation. Biodistribution experiments with [¹²⁵I]3 and [¹²⁵I]9 showed similar distribution patterns with high retention in tumors. In photodynamic therapeutic (PDT) experiments, 3 and 9 at a dose of 13.6 μmol kg^-1 weight with 50 W single light irradiation onto the tumor area significantly inhibited tumor growth. These results indicate that the iodinated porphyrin derivatives [^123/natI]3 and [^123/natI]9 are promising cancer theranostic agents.