New Hydrophilic/Lipophilic Tetra-α-(4-carboxyphenoxy) Phthalocyanine Zinc-Mediated Photodynamic Therapy Inhibits the Proliferation of Human Hepatocellular Carcinoma Bel-7402 Cells by Triggering Apoptosis and Arresting Cell Cycle

Abstract

Photodynamic therapy (PDT) is a novel and promising antitumor treatment. Phthalocyanine-mediated PDT has shown antitumor activity in some tumor cells, but the effect of new hydrophilic/lipophilic tetra-α-(4-carboxyphenoxy)phthalocyanine zinc (TαPcZn)-mediated PDT (TαPcZn-PDT) on human hepatocellular carcinoma Bel-7402 cells and underlying mechanisms have not been clarified. In the present study, therefore, the ultraviolet-visible (UV-vis) absorption spectrum and cellular localization of TαPcZn, and effect of TαPcZn-PDT on the proliferation, apoptosis, cell cycle, Bcl-2 and Fas in Bel-7402 cells were investigated by spectrophotometry, inverted microscope, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay, electron microscopy, annexinV-FITC/propidium iodide double staining, DNA content and immunoblot assay, respectively. We found that an intense absorption in UV-vis absorption spectrum of TαPcZn was in the red visible region at 650–680 nm, where light penetration in tissue is efficient, that green TαPcZn localized to both plasma membrane and nuclear membrane of Bel-7402 cells, signifying that there was a selective uptake of TαPcZn in Bel-7402 cells and TαPcZn-PDT would be expected to directly damage DNA, and that TαPcZn-PDT significantly resulted in the proliferation inhibition, apoptosis induction, S cell cycle arrest, and down-regulation of Bcl-2 and Fas. Taken together, we conclude that TαPcZn-PDT inhibits the proliferation of Bel-7402 cells by triggering apoptosis and arresting the cell cycle.

Keywords

• tetra-α-(4-carboxyphenoxy) phthalocyanine zinc
• photodynamic therapy
• human hepatoma Bel-7402 cells
• proliferation
• apoptosis
• cell cycle