Abstract
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 cellmorphology, 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 𝜇Mof 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.