Differential secretome analysis of cancer‐associated fibroblasts and bone marrow‐derived precursors to identify microenvironmental regulators of colon cancer progression

Abstract

The identification of cancer-associated fibroblast (CAF)-derived proteins that mediate interactions between the tumor stroma and cancer cells is a crucial step toward the discovery of new molecular targets for therapy or molecular signatures that improve tumor classification and predict clinical outcome. CAF are α-smooth muscle actin positive, representing a myofibroblast phenotype that may differentiate from multiple precursor cells, including bone marrow-derived mesenchymal stem cells (MSC). Transforming growth factor-β1 (TGF-β1) is a crucial inducer of α-smooth muscle actin positive CAFs. In this study, we aimed to identify CAF-derived regulators of colon cancer progression by performing a high-throughput differential secretome profiling between CAF compared to noncancer-activated bone marrow-derived MSC. In addition, we explored the effect of TGF-β1 on the secretion of proteins by bone marrow-derived MSC in comparison with the protein secretion profile of CAF. TGF-β1 induced de novo secretion of 84 proteins in MSC, of which 16 proteins, including stromal-derived factor-1α and Rantes, were also present in CAF secretome. Immunohistochemistry further validated the expression of selected candidates such as tenascin C, fibronectin ED-A domain and stromal-derived factor-1 in clinical colon cancer specimens. In conclusion, this differential secretome approach enabled us to identify a series of candidate biomarkers for colon cancer that are associated with a CAF-specific phenotype.

Secretome profiling of oral squamous cell carcinoma-associated fibroblasts reveals organization and disassembly of extracellular matrix and collagen metabolic process signatures

“…This was previously described in other studies that investigated CAFs derived from other tumors [18,19,22,52]. In a recent study, Rasanen and collaborators [20] characterized the secretomes of E-cadherin low mesenchymal-like subpopulations of OSCCs, which resembled that of CAFs, and revealed upregulation of several proteins involved in organization of the extracellular matrix, such as multiple types of collagen.…”

“…Identifying proteins synthesized by CAFs is crucial for a better understanding of the biological events associated with oral tumorigenesis and for the discovery of new tumor biomarkers, enabling, for example, discrimination of patients at high and low risk of developing metastasis and allowing for more individualized treatment. Previous studies have already identified proteins secreted by CAFs in colorectal [18,19], head and neck cancer [20], and nasopharyngeal cancer [21]. In a previous study, we demonstrated that CAFs promote tumorigenesis of oral tongue SCC cell lines via secretion of high levels of activin A, a member of the transforming growth factor-β superfamily of proteins [8].…”

LOXL2 Is Highly Expressed in Cancer-Associated Fibroblasts and Associates to Poor Colon Cancer Survival

“…Recently, a comparative transcriptomic analysis of paired CAFs and normal fibroblasts (NF) identified 108 genes, mostly downregulated (17). In a proteomic study, colon cancer CAFs were compared with bone marrow precursors to identify tenascin C, ED-A fibronectin, and SDF-1 as deregulated in CAFs (18). Recently, we used a murine model of sporadic colon cancer based on azoxymethane/dextran sodium sulfate to optimize fibroblast purification and characterize alterations in murine CAFs (19).…”

Tumor-environment biomimetics delay peritoneal metastasis formation by deceiving and redirecting disseminated cancer cells

“…Human CAF were isolated from a colorectal adenocarcinoma resection specimen obtained in accordance with the local ethics committee (Ghent University Hospital) described by De Boeck et al [9,14]. In sort, tissue fragments were cut in small pieces and transferred into a 6-well late fetal FBS.…”

“…CAFs secrete a range of ECM proteins (e.g. type I collagen, tenascine C) creating a receptive adhesive environment for peritoneal implant formation [9].…”