Study Of Protein Acetylation Modification On The Occurrence And Development Of Colorectal Carcinoma Regulated By Black Raspberry Anthocyanin

Colorectal cancer(CRC)is one of most common malignant cancers,and the incidence of colorectal cancer in China is increasing year by year.Epigenetic changes play an important role in the early development and progression of colorectal cancer.The acetylation modification of proteins is one of the most important epigenetic regulation.Studies have shown that histone acetylation plays an important role in maintaining the expression level of tumor suppressor genes.The acetylation modification of lysine residues is reversible,and this process neutralizes the positive charge of the amino acids and modulates protein activity in different ways.The balance of acetylation kinetics in vivo is regulated by Histone deacetylase(HDACs)and Histone acetylase(HATs).Abnormal acetylation levels are involved in the occurrence and development of colorectal cancer.Black raspberry is rich in polyphenolic compounds,mainly anthocyanin.Previous study in our laboratory found that black raspberry anthocyanin(BRB anthocyanin)could play important chemoprevention effects in inflammation associated colon cancer mouse model via SIRT1,one of members in HDACs family.In this study,AOM-induced colorectal cancer mouse model and human colorectal cancer cells were used to explore the role of acetylation modification of protein in blackberry anthocyanins regulated occurrence and development of colorectal cancer.The results showed:1.In vivo study:(1)The results showed that black raspberry anthocyanin can up-regulate the pan-acetylation level of the protein in mouse intestinal epithelial cells of colorectal cancer mice induced by AOM.Down-regulated protein level of SIRT1 and up-regulated protein level of EP300 and MOF protein were observed in Black raspberry anthocyanin supplemented group mice.In addition,acetylation level of H4 histone K5?K12?K16 also were increased.(2)The acetylation modification on Non-histone protein p65,and the influences on its downstream related signaling molecules were investigated also.Results showedthat black raspberry anthocyanin can increase the level of ac-p65 in intestinal epithelial cells of mice induced by AOM.Ac-p65 downstream signaling pathway associated factor,Bax was up-regulated,while Bcl-2 was down-regulated by Black raspberry anthocyanin.In addition,the protein level of cyclin-D1 and c-myc was also down-regulated by Black raspberry anthocyanin.(3)Immunofluorescence assay showed that black raspberry anthocyanin could reduce the release of ROS;NOX2 mediated NLRP3 inflammasome activation in mice was inhibited by black raspberry anthocyanin in intestinal epithelial cells of mice induced by AOM..2.In vitro experiments: Human Colorectal cancer cell lines SW480 and Caco-2were treated with different concentrations of black raspberry anthocyanin(0?g/mL,25?g/mL and 50?g/mL)for 24 h.(1)The pan-acetylation level of the protein in human colorectal cancer cells was increased by black raspberry anthocyanin.Black raspberry anthocyanin could down-regulate the expression of SIRT1 protein,while up-regulate the level of EP300 and MOF protein in human colorectal cancer cells.Futher the acetylate level of K5,K12 and K16 lysine sites of H4 histone were also up-regulated by Black raspberry anthocyanin.(2)In human colorectal cancer cells,Black raspberry anthocyanin could up-regulate the acetylation level of non-histone protein p65.Bax was upregulated;Bcl-2 was down-regulated,and the level of cyclin-D1 and c-myc protein was also down-regulated by Black raspberry anthocyanin.The nuclear trans-localization of p-p65 was increased by black raspberry anthocyanin in SW480 cells.(3)Black raspberry anthocyanin inhibited the protein level of NOX2 and NLRP3 in human colorectal cancer cells.In summary,the level of the pan-acetylation of proteins was up-regulated by black raspberry anthocyanin and which might partiality be regulated by SIRT1,MOF and EP300.The acetylation level of H4 histone K5,K12,K16 was increased by black raspberry anthocyanin.The acetylation of non-histone p65 and its associated downstream factors were also could be regulated by black raspberry anthocyanin.The current finding suggested that acetylation modification of proteins plays an importantrole in the occurence and development of colorectal cancer regulated by black raspberry anthocyanin.