Investigation of combined photodynamic and radiotherapy effects of gallium phthalocyanine chloride on MCF-7 breast cancer cells.

In this study, we evaluated the effect of gallium phthalocyanine chloride (GaPcCl) as a radio- and photosensitizer on MCF-7 breast cancer cell line. We incubated cells with GaPcCl in different concentrations (from 3.125 to 100 µg/ml). Then cells in separate groups were exposed to different light doses (1.8 and 2.8 J/cm2) at wavelength of 660 nm and 2-Gy X-ray ionizing radiation, alone and in combination. Finally, cell survival and apoptosis were determined by MTT assay and flow cytometry, respectively. The results showed that the deactivated GaPcCl at concentration of 100 µg/ml reduces the cell viability up to 15%. While, photoactivated GaPcCl (100 µg/ml) at light dose of 2.8 J/cm2 significantly decreases cell viability up to 55.3%. Although MTT assay demonstrated that GaPcCl is not act as a radiosensitizer, flow cytometry showed significant increase in cell apoptosis when GaPcCl was exposed to 2 Gy X-ray. Using of GaPcCl-PDT (photodynamic therapy) integration with X-ray substantially increased cell death in comparison to the absence of X-ray. Furthermore, flow cytometry displayed a significant increase in apoptosis cells (especially late apoptosis) in this combination therapy. Our result proved that GaPcCl is an effective photosensitizer in MCF-7 human breast cancer cell line. The combination of GaPcCl-PDT and radiotherapy can be an efficient treatment against cancer. This approach needs further investigations on animal models for human purposes.Graphic abstract.

Collagen Hydrolysate Effects on Photodynamic Efficiency of Gallium (III) Phthalocyanine on Pigmented Melanoma Cells.

The conjugation of photosensitizer with collagen seems to be a very promising approach for innovative topical photodynamic therapy (PDT). The study aims to evaluate the effects of bovine collagen hydrolysate (Clg) on the properties of gallium (III) phthalocyanine (GaPc) on pigmented melanoma. The interaction of GaPc with Clg to form a conjugate (GaPc-Clg) showed a reduction of the intensive absorption Q-band (681 nm) with a blue shift of the maximum (678 nm) and a loss of shape of the UV-band (354 nm). The fluorescence of GaPc, with a strong emission peak at 694 nm was blue shifted due to the conjugation which lower intensity owing to reduce quantum yield (0.012 vs. 0.23, GaPc). The photo- and dark cytotoxicity of GaPc, Glg and GaPc-Clg on pigmented melanoma cells (SH-4) and two normal cell lines (BJ and HaCaT) showed a slight decrease of cytotoxicity for a conjugate, with low selectivity index (0.71 vs. 1.49 for GaPc). The present study suggests that the ability of collagen hydrolysate to form gels minimizes the high dark toxicity of GaPc. Collagen used for conjugation of a photosensitizer might be an essential step in advanced topical PDT.