A H2O2-Responsive Boron Dipyrromethene-Based Photosensitizer for Imaging-Guided Photodynamic Therapy

In this study, we demonstrate a novel H2O2 activatable photosensitizer (compound 7) which contains a diiodo distyryl boron dipyrromethene (BODIPY) core and an arylboronate group that quenches the excited state of the BODIPY dye by photoinduced electron transfer (PET). The BODIPY-based photosensitizer is highly soluble and remains nonaggregated in dimethyl sulfoxide (DMSO) as shown by the intense and sharp Q-band absorption (707 nm). As expected, compound 7 exhibits negligible fluorescence emission and singlet oxygen generation efficiency. However, upon interaction with H2O2, both the fluorescence emission and singlet oxygen production of the photosensitizer can be restored in phosphate buffered saline (PBS) solution and PBS buffer solution containing 20% DMSO as a result of the cleavage of the arylboronate group. Due to the higher concentration of H2O2 in cancer cells, compound 7 even with low concentration is particularly sensitive to human cervical carcinoma (HeLa) cells (IC50 = 0.95 μM) but hardly damage human embryonic lung fibroblast (HELF) cells. The results above suggest that this novel BODIPY derivative is a promising candidate for fluorescence imaging-guided photodynamic cancer therapy.

Synthesis and high in vitro cytotoxicity of some (S,S)-ethylenediamine-N,N’-di-2-propanoate dihydrochloride esters

Novel (S,S)-R2eddip ester, O,O?-diisoamyl-(S,S)-ethylenediamine-N,N?-di-2-propanoate dihydrochloride, 1, was synthesized and characterized by IR, 1H and 13C NMR spectroscopy, mass spectroscopy and elemental analysis.In vitro antitumor action of 1, and two more R2eddip esters, O,O?-dialkyl-(S,S)-ethylenediamine-N,N?-di-2-propanoate dihydrochlorides, obtained before, (alkyl = n-Bu, n-Pe; 2 and 3, respectively), was determined against cervix adenocarcinoma (HeLa), human melanoma (Fem-x), human chronic myelogenous leukemia (K562) cells, and a non-cancerous cell line human embryonic lung fibroblast (MRC-5), using MTT assay. Esters 1-3 showed higher cytotoxicity and better selectivity in comparison to cisplatin, used as reference compound. The highest activityis expressed by1,with IC50(Fem-x)value1.51 ? 0.09 ?M.