DETERMINATION OF EFFECTS AND OPTIMIZATION OF PHOTOBIOMODULATION AND PHOTODYNAMIC THERAPY PARAMETERS FOR PROSTATE AND BREAST CANCER CELL LINES OF DIFFERENT MALIGNANCY GRADE

Lykhova O.O., Konovalenko S.V., Chepurna O.M.

• R.E. Kavetsky Institute of Experimental Pathology, Oncology and Radiobiology, NAS of Ukraine, Kyiv, Ukraine

Aim: to investigate the effects of laser radiation of different intensities on prostate cancer (PC) and breast cancer (BC) cell lines; to evaluate the prospects of combining light stimulation (photobiomodulation) and chemotherapy for synergistic effects on tumor cells. Object and methods: PC cell lines of different malignancy grade (LNCaP and DU-145) and BC cell line (MCF-7) were used in the study. The radiation of the semiconductor laser device (Photonics Plus, Ukraine) with wavelengths of 405, 445, 660, 635 and 810 nm was used to irradiate cells. The power of light radiation was measured using an optical radiation meter Ophir Optronics (USA). As the photosensitizer (PHS), 5-aminolevulinic acid (5-ALA) (1 mmol) was applied to LNCaP and DU-145 cells; doxorubicin (DOX) at a concentration of 1 μg/ml was added to the MCF-7 cells. The statistical analysis of the results was performed with the software package Statistics 6.0. Results: It has been found out on PC cells lines (LNCaP and DU-145) that the most optimal parameters of laser radiation for obtaining the highest photodynamic activity of 5-ALA are as follows: wavelength 405 nm, irradiation time 10 min, power density 20 mV/cm². It has been shown that the cytotoxic effect of DOX towards BC cells (MCF-7) is enhanced by laser radiation with the wavelength of 445 nm, which is equal to the peak of DOX absorption. Additionally, used as photobiomodulation, laser radiation with a wavelength of 810 nm before the administration of chemotherapeutical drug can increase its overall toxic effect on MCF-7 cells. Conclusions: the use of laser radiation with the wavelength which is equivalent to the chemotherapeutical drug absorption peak can increase its toxic effects without increasing the dose and irradiation time. The additional application of laser radiation for photobiomodulation increases the overall toxic effect of a chemotherapeutic agent towards tumor cells.