Effect of 5-aminolevulinic acid mediated photodynamic therapy on proliferation and apoptosis of gastric cancer cell line MKN-45

Abstract

Objective To explore the 5-aminolevulinic acid (5-ALA) mediated photodynamic therapy(PDT) for proliferation and apoptosis of gastric cancer cell line MKN-45. Methods The human gastric cancer cell line MKN-45 was cultured in vitro. The MTT method was used to detect fixed lighting processing (laser radiation dose fixed for 25.00 J/cm2, 5-ALA photosensitizer concentrations were 0 mmol/L, 0.25 mmol/L, 0.50 mmol/L, 1.00 mmol/L, 2.00 mmol/L), fixed photosensitizer concentration treatment (5-ALA photosensitizer concentrations fixed to 1.00 mmol/L, laser radiation dose were 0 J/cm2, 6.25 J/cm2, 12.50 J/cm2, 25.00 J/cm2, 50.00 J/cm2, 100.00 J/cm2) of the cell apoptosis rate, and then fixed 5-ALA photosensitizer 1 mmol/L and selected the control group, 5-ALA group, pure illumination group and PDT group. The promoting effect on cell apoptosis was determined by MTT, electron microscope and flow cytometry. The activity of human gastric cancer cells MKN-45 apoptosis related proteins p65 and the downstream gene regulatory protein bcl-2, bax, caspase-3 and caspase-9 were detected by using Western blot method. Results When laser radiation dose was fixed, 5-ALA photosensitizer concentrations in promoting gastric cancer cell apoptosis was positively related to the dominant (P < 0.01). When 5-ALA photosensitizer concentration was fixed, laser radiation dose effect had no longer dominant after 25.00 J/cm2 positive correlation (P = 0.613). When 5-ALA photosensitizer concentration was fixed in 1 mmol/L, compared to control group, 5-ALA group and pure illumination group, the inhibition of the MKN-45 cell proliferation in PDT group was more apparently, apoptosis rate increased obviously, signal pathways in cell apoptosis protein involved in the NF-kappa B p65 expression was reduced, the downstream gene regulation of target protein bcl-2, caspase-3 and caspase-9 expression were reduced, and bax protein expression was increased. Conclusions 5-ALA mediated photodynamic has a strong inhibitory effect on the growth of gastric cancer cell line MKN-45 in vitro. It can significantly increase the apoptosis rate of gastric cancer cells, and the effect may be carried out by activating the NF-kappa B pathway. Key words: 5-aminolevulinic acid; Photochemotherapy; Stomach neoplasms; Apoptosis