Identification of AOC3 and LRRC17 as Colonic Fibroblast Activation Markers and Their Potential Roles in Colorectal Cancer Progression

• Published in: Asian Pacific Journal of Cancer Prevention
• Main Author: Zawawi S.S.A.; Azram N.A.S.M.; Sulong S.; Zakaria A.D.; Lee Y.Y.; Jalil N.A.C.; Musa M.
• Format: Article
• Language: English
• Published: Asian Pacific Organization for Cancer Prevention 2023
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85173448530&doi=10.31557%2fAPJCP.2023.24.9.3099&partnerID=40&md5=62f37454b2bb848e52163c3ba98c1144

Background: Accumulation of cancer-associated fibroblasts (CAFs) in the tumor stroma is linked to poor prognosis in colorectal cancer (CRC). CAF-cancer cell interplay, facilitated by secretomes including transforming growth factor-beta 1 (TGF-β1), supports fibroblast activation, drives colorectal carcinogenesis, and contributes to CRC aggressive phenotypes. Although widely used, traditional CAF biomarkers are found to have heterogeneous and non-specific expression. Amine oxidase copper containing 3 (AOC3) and leucine-rich repeat-containing 17 (LRRC17) have been reported to be emerging markers of myofibroblasts. Aim: Our objective was to investigate the potential of AOC3 and LRRC17 as biomarkers for fibroblast activation thus predicting their roles in CRC progression. Methods: Immunofluorescence (IF) staining of AOC3 and LRRC17 was performed on myofibroblast line (CCD-112CoN), primary fibroblasts from colorectal tumor (CAFs), and adjacent normal tissue (normal fibroblasts-NFs). SW620 (epithelial CRC cell line) was used as a control. Conventional CAF biomarker (alpha-smooth muscle actin - α-SMA) was included in the IF analysis. Fluorescence intensity was compared between groups using ImageJ software. Proliferation and contractility of treated cells were assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and collagen gel contraction assays, respectively. Fibroblast contraction under TGF-β1 treatment was compared to those treated with complete medium (addition of 10% serum) and serum free (SF) medium. Results: Positive AOC3, LRRC17, and α-SMA expression were observed in colonic fibroblasts, more prominent in CAFs, whereas negative staining was found in SW620. Significant downregulation of AOC3, and upregulations in LRRC17 and α-SMA expression was found in TGF-β1-treated fibroblasts compared to SF medium treatment (p-value<0.05). All fibroblasts exhibited higher proliferation in complete medium and under treatment with conditioned medium from SW620 than SF medium. Significant contraction of NFs was recorded in complete medium and TGF-β1 (p-value<0.01). Conclusion: Our results demonstrate AOC3 and LRRC17 as the potential markers of CAF activation which promote CRC progression. © This work is licensed under a Creative Commons Attribution-Non Commercial 4.0 International License.