Combined regimen of photodynamic therapy mediated by Gallium phthalocyanine chloride and Metformin enhances anti-melanoma efficacy

Abstract

BackgroundMelanoma therapy is challenging, especially in advanced cases, due to multiple developed tumor defense mechanisms. Photodynamic therapy (PDT) might represent an adjuvant treatment, because of its bimodal action: tumor destruction and immune system awakening. In this study, a combination of PDT mediated by a metal substituted phthalocyanine—Gallium phthalocyanine chloride (GaPc) and Metformin was used against melanoma. The study aimed to: (1) find the anti-melanoma efficacy of GaPc-PDT, (2) assess possible beneficial effects of Metformin addition to PDT, (3) uncover some of the mechanisms underlining cell killing and anti-angiogenic effects.MethodsTwo human lightly pigmented melanoma cell lines: WM35 and M1/15 subjected to previous Metformin exposure were treated by GaPc-PDT. Cell viability, death mechanism, cytoskeleton alterations, oxidative damage, were assessed by means of colorimetry, flowcytometry, confocal microscopy, spectrophotometry, ELISA, Western Blotting.ResultsGaPc proved an efficient photosensitizer. Metformin addition enhanced cell killing by mechanisms dependent on the cell line, namely apoptosis in the metastatic M1/15 and necrosis in the radial growth phase, WM35. Cell death mechanism relied on the inhibition of nuclear transcription factor (NF)-κB activation and tumor necrosis factor (TNF)—related apoptosis-inducing ligand (TRAIL) sensitization, leading to TRAIL and TNF-α induced apoptosis. Metformin diminished the anti-angiogenic effect of PDT.ConclusionsMetformin addition to GaPc-PDT increased tumor cell killing through enhanced oxidative damage and induction of proapoptotic mechanisms, but altered PDT anti-angiogenic effects.General significanceCombination of Metformin and PDT might represent a solution to enhance the efficacy, leading to a potential adjuvant role of PDT in melanoma therapy.

A Novel Thiazolyl Schiff Base: Antibacterial and Antifungal Effects and In Vitro Oxidative Stress Modulation on Human Endothelial Cells

“…The cell lysates used in the following experiments were prepared as previously described [33]. Protein concentrations were determined by the Bradford method, according to the manufacturer's specifications (Bio-Rad, Hercules, California, USA) and using bovine serum albumin as standard.…”

“…TNF- α ELISA Immunoassay kit from R&D Systems, Inc. (Minneapolis, USA) was used. Cell supernatants were treated according to the manufacturer's instructions; readings were done at 450 nm with correction wavelength set at 540 nm, using an ELISA plate reader (Tecan) [33].…”

Metformin as an Adjuvant to Photodynamic Therapy in Resistant Basal Cell Carcinoma Cells

“…First, the cells were incubated for 24 h with Metf. Afterwards, the medium with Metf was replaced by that of MAL (0.2 mM) and further incubated for 5 h. Subsequently, cells were irradiated with the red light source and the medium with MAL was replaced by fresh DMEM with 10% FBS and incubated for 24 h until evaluation [48].…”

Unveiling Ga(III) phthalocyanine—a different photosensitizer in neuroblastoma cellular model

“…Furthermore, the Ga‐compound was solubilized in dimethylsulphoxide (DMSO) in order to obtain a 1 mmol/L stock solution that was further diluted in cell medium to prepare all working solutions for cellular testing systems. The DMSO final concentration in the medium was <0.05% non‐toxic for cells . For irradiation PDT experiments, quartz cuvettes with 0.5‐2 cm optical path lengths containing 1 mL of SHSy5Y cell suspension each were used .…”

“…The DMSO final concentration in the medium was <0.05% non-toxic for cells. 17 For irradiation PDT experiments, quartz cuvettes with 0.5-2 cm optical path lengths containing 1 mL of SHSy5Y cell suspension each were used.…”