Apoptosis Mechanisms Of Colorectal Cancer Cells By Combination Of Light Irradiation And Chemotherapy Drugs Involved In Death Receptor Pathway

Colorectal cancer is a malignant tumor of the digestive tract that occurs in the colon.It is the fourth cancer with the highest death rate in the world.At present,the main treatment is surgery,supplemented by chemotherapy and radiation therapy.Although these methods can cause tumor regression temporarily,they all have inevitable side effects and cannot cure cancer.Inspired by cocktail therapy,we have developed a multi-target treatment method innovatively that uses blue LED(465 nm)irradiation in combination with the chemotherapy drugs AT406 and Rocaglamide invented base on the tumor cell death receptor pathway to treat colorectal cancer and we find the appropriate irradiation durations and optimal drug concentration.Blue LED combined with AT406 and Rocaglamide can promote the apoptosis of colorectal cancer cells in vitro,and few human normal cells will be affected.When it is applied to the colorectal cancer cell line HCT116 which in an undifferentiated state,3h blue LED radiation and 178 n M AT406,6 n M Rocaglamide can cause HCT116 cell apoptosis rate to 82%;while 4h blue irradiation and 445 n M AT406 and 20 n M Rocaglamide can make the apoptosis rate of HCT116 cells reach 90%.5h blue irradiation and 1785 n M AT406,40 n M Rocaglamide can cause 95% of HCT116 cell apoptosis.It also has a strong pro-apoptotic effect on the colorectal cancer cell lines HT29 which has been moderately differentiated.3h blue LED and 13 ?M AT406,50 n M Rocaglamide can kill about 75% of HT29 cells;4h blue LED combined with 50 ?M AT406,200 n M Rocaglamide can cause about 82% of HT29 cell apoptosis;5h blue LED combined with 100 ?M AT406,800 n M Rocaglamide can cause up to about 90% apoptosis rate.When the human normal diploid cell embryonic lung fibroblast MRC-5 is treated under the same conditions,less than 25% of the cells will be affected,and the cell morphology will shrink slightly without causing a large amount of apoptosis.We also explored its pro-apoptotic mechanism.Western Blot and flow cytometry results showed that the combination of blue LED radiation and two anti-cancer drugs can activate Caspase-3,Caspase-8 and C-JUN and other pathways,and Inhibits the expression of Bcl-2,ERK1/2,LC3 B and P38 pathways,and the reactive oxygen content in the cells increases significantly after the reaction.We infer that the combination of blue LED and AT406,Rocaglamide promote apoptosis of colorectal cancer cells by activating apoptosis pathways,inhibiting autophagy and proliferation pathways,and generating reactive oxygen species(ROS).This experiment explores a colorectal cancer cells treatment with good efficacy,small side effects,good repeatability and high specificity,which can provide a theoretical basis for the next animal experiments and even future clinical applications.