While
photodynamic therapy (
PDT) has been recognized as a promising therapeutic modality for the treatment of various
cancers and diseases, developments of effective
photosensitizers are highly desired to improve the prospect for the use of
PDT. In this study, we evaluated DH-II-24, a new
photosensitizer, for antitumor
PDT in vitro and in vivo. Loaded into human
colorectal carcinoma cells (HCT116), DH-II-24 was primarily accumulated in mitochondria, lysosomes, and endoplasmic reticula. Administration of DH-II-24 followed by light exposure induced necrotic cell death in a dose-dependent manner, whereas DH-II-24 in the absence of light induced minimal cell death. In order to investigate the distribution and phamacokinetics of the
photosensitizer in vivo, DH-II-24 was intravenously injected to female BALB/c nude mice. Fluorescence imaging in vivo showed that DH-II-24 was rapidly distributed across the entire body and then mostly eliminated at 24 h. Next, effectiveness of DH-II-24-mediated
PDT was examined on
colorectal carcinoma xenografts established subcutaneously in BALB/c nude mice. DH-II-24 (1 mg/kg, i.v. administration) followed by light exposure significantly suppressed growth of xenograft
tumors, compared to light exposure or DH-II-24 alone. Histological examination revealed necrotic damage in
PDT-treated
tumors, concomitantly with severe damage of
tumor vasculature. These results suggest that DH-II-24 is a potential
photosensitizer of
photodynamic therapy for
cancer.