ADAM-17/FHL2 colocalisation suggests interaction and role of these proteins in colorectal cancer.

FHL2is a multifunctional scaffolding protein; its expression is associated with poor prognosis in colorectal cancer. ADAM-17 is a metalloprotease implicated in ectodomainshedding. FHL2regulates ADAM-17 plasma membrane localisation, and FHL2deficiency leads to decreased activity of ADAM-17 in mouse macrophages. Presence and relationship of the ADAM-17/ FHL2complex with colorectal cancer progression is unknown. We studied FHL2and ADAM-17 expression in several colon cancer cell lines by immunocytochemistry and western blot. To highlight the interaction between both molecules, we used the Duolink (R) kit for proximity ligation assayon SW480 cells. We also performed proximity ligation assayon biopsies and surgical specimens of colorectal adenocarcinomaand on matched normal mucosa. Furthermore, biopsies of colorectal adenomawith matched normal mucosa were selected. For quantification, pictures of the malignant, adenomatous and normal tissues were taken. Proximity ligation assaysignals were quantified. Mean numbers of proximity ligation assaysignals and of proximity ligation assaysignals/nucleus were calculated. All cell lines showed FHL2immunoreactivity; strongest positivity was observed in SW480 cells. ADAM-17 was expressed in all cell lines. Proximity ligation assaysignals were present in SW480 cells. Quantitative analysis revealed that the interaction between FHL2and ADAM-17 is more frequent in malignant than in normal tissue (p = 0.005). The mean number of ADAM-17/ FHL2 proximity ligation assaysignals was higher in colorectal adenocarcinomathan in adenoma with low-grade dysplasia (p = 0.0004). FHL2interacts with ADAM-17 in normal, dysplastic and malignant colon epithelial cells. Colocalisation of these proteins is more frequent in malignant than in normal and dysplastic cells, suggesting a role for ADAM-17/ FHL2complex in the development of colorectal cancer.