Susceptibility of In Vitro Melanoma Skin Cancer to Photoactivated Hypericin versus Aluminium(III) Phthalocyanine Chloride Tetrasulphonate

The sensitivity of human melanoma cells to photoactivated Hypericin (Hyp) compared to aluminium(III) phthalocyanine chloride tetrasulphonate (AlPcS₄Cl) is reported in this study. Melanoma cells (A375 cell line) were treated with various concentrations of Hyp or AlPcS₄Cl alone, for 1, 4, and 24 hrs; varying doses of laser irradiation alone (594 or 682 nm); or optimal concentrations of PSs combined with laser irradiation. Changes in cell morphology, viability, membrane integrity, and proliferation after treatment of cells were determined using inverted microscopy, Trypan blue cell exclusion, Lactate Dehydrogenase (LDH) membrane integrity, and adenosine triphosphate (ATP) cell proliferation assay, respectively. More than 60% of cell survival was observed when cells were treated with 2.5 μM of Hyp or AlPcS₄Cl alone at all incubation times or with 5 J/cm² of 594 or 682 nm laser alone. Combination of PSs and respective lasers leads to a statistically significant incubation time-dependent decrease in survival of cells. Flow cytometry using the FITC Annexin V/PI apoptosis kit demonstrated that cell death induced after Hyp-PDT is via early and late apoptosis whereas early apoptosis was the main mechanism observed with AlPcS₄Cl-PDT. Hyp-PDT compared to AlPcS₄Cl-PDT is indicated to be a more effective cancer cell death inducer in melanoma cells.