Antimicrobial peptide LL-37 in macrophages promotes colorectal cancer growth
10.3760/cma.j.issn.0253-3766.2018.06.003
- VernacularTitle: 抗菌肽LL-37在巨噬细胞促进结直肠癌生长中的作用及其分子机制
- Author:
Xinghao PAN
1
;
Wenqiang QUAN
2
;
Junlu WU
2
;
Weidong XIAO
1
;
Zujun SUN
2
;
Dong LI
2
Author Information
1. School of Biomedical Sciences, Huaqiao University, Quanzhou 362021, China
2. Department of Clinical Laboratory, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
- Publication Type:Journal Article
- Keywords:
Colorectal neoplasm;
LL-37;
Co-culture;
Wnt/β
-catenin pathway
- From:
Chinese Journal of Oncology
2018;40(6):412-417
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the effect and molecular mechanism of antimicrobial peptide LL-37 secreted by stromal cells on the growth of colorectal cancer cells.
Methods:Colorectal cancer cells SW480 or HCT116 were co-cultured with human macrophages using Transwell® maxicell inserts to mimic the tumor microenvironment. The effect of macrophages on the proliferation of colorectal cancer cells was detected by Bromodeoxyuridine and enzyme-linked immunosorbent assay (BrdU-ELISA). The expression of LL-37 mRNA and protein in macrophages and colorectal cancer cells was evaluated by reverse transcription-real-time quantitative PCR (RT-qPCR) and Western blot. LL-37 neutralizing antibody was added to abrogate the LL-37 activation. Additionally, macrophages were transfected with LL-37 shRNA plasmids to inhibit LL-37 expression. And then, the proliferation of colorectal cancer cells was observed. Furthermore, the growth-related signaling pathways were detected by Western blot.
Results:The BrdU-ELISA results showed that the absorbance of SW480 cells increased from 1.072±0.097 to 5.121±0.407 after co-culture (P<0.001), and that of HCT116 cells increased from 1.229±0.073 to 3.495±0.228 (P<0.001). RT-qPCR results showed that LL-37 mRNA expression in macrophages significantly increased from 2.682±0.191 to 6.117±0.768 after co-incubation (P<0.05), whereas that in SW480 had no significant difference. Consistently the protein expression of LL-37 in macrophages was significantly increased by Western blot, while it did not change in SW480. The proliferation rate of SW480 cells was repressed by adding LL-37 neutralizing antibody or LL-37 shRNA plasmid. Furthermore, Western blot analysis showed that the expression of non-phosphorylated (activated) β-catenin and its target genes cyclin D1 as well as c-myc were distinctly increased in co-cultured SW480 cells, which could be reversed by anti-LL-37 antibodies.
Conclusion:Macrophages promote the in vitro proliferation of colorectal cancer cells by enhancing the expression and secretion of antimicrobial peptides LL-37, and it seems that LL-37 activates colorectal cancer cells via Wnt/β-catenin pathway.
