Photosensitization of hematoporphyrin monomethyl ether enhance cellular concentrations of AS-ODNs targeting Bcr-abl gene in K562 cells and efficacy of AS-ODNs killing K562 cells

This study was to investigate the effect of photosensitization of Hematoporphyrin monomethyl ether (HMME) on the intracellular uptake of antisense oligonucleotides (AS-ODNs) and cytotoxicity of AS-ODNs targeting bcr-abl gene in K562 cells. The cells were randomized into the experimental group and the controls. The cells in the experimental group were treated by photosensitization of HMME with AS-ODNs. The cells in the controls were treated by photosensitization of HMME, AS-ODNs alone, HMME treatment alone, laser radiation alone or sham radiation, respectively. Light source was from laser with red light (650 nm) delivered at a total dose of 9 J cm(-2). The intracellular uptake of AS-ODNs was measured with flow cytometry and fluorescence microscope, and the proliferation of K562 cells was investigated by colony formation and cell cycle distribution was analyzed by flow cytometry and apoptosis was measured with terminal deoxyuridine nicked-labeling (TUNEL) assay. The results showed that the cells treated by photosenstization have higher fluorescence intensity compared with the cells in the controls. At 24 h after photosensitization with AS-ODNs, a 31% increase in the proportion of cells in the G0-G1 phase relative to sham irradiation was observed and G1 arrest,occurred concurrently with a reduction in the percentage of S-phase cells and the rate of apoptosis in K562 cells significantly increased up to 8.60 +/- 0.04%. At 14(th) day, treatment of photosensitization with AS-ODNs resulted in a significant decrease in colony formation in K562 cells. Our data demonstrate that photosensitization of HMME could enhance intracellular concentrations of AS-ODNs in K562 cells and increase the efficacy of AS-ODNs killing cells. Combination of photosensitization of HMME with AS-ODNs may be of value for more effective management of cancer.