FHL2 expression in peritumoural fibroblasts correlates with lymphatic metastasis in sporadic but not in HNPCC-associated colon cancer

Abstract

Four and a half LIM domain protein-2 (FHL2) is a component of the focal adhesion structures and has been suggested to have an important role in cancer progression. This study analyses the role of FHL2 in peritumoural fibroblasts of sporadic and hereditary non-polyposis colorectal cancer (HNPCC). Tissue specimens of 48 sporadic and 49 hereditary colon cancers, respectively, were stained immunohistochemically for FHL2, transforming growth factor (TGF)-b1 ligand and a-SMA. Myofibroblasts at the tumour invasion front co-expressed a-SMA and FHL2. Sporadic colon cancer but not HNPCC cases showed a correlation between TGF-b1 expression of the invading tumour cells and FHL2 staining of peritumoural myofibroblasts. Overexpression of FHL2 in peritumoural myofibroblasts correlated to lymphatic metastasis in sporadic colon cancer but not in HNPCC. In cultured mouse fibroblasts, TGF-b1 treatment induced myofibroblast differentiation, stimulated FHL2 protein expression and elevated number of migratory cells in transwell motility assays, suggesting that FHL2 is regulated downstream of TGF-b. Physical contact of colon cancer cells and myofibroblasts via FHL2-positive focal adhesions was detected in human colon carcinoma tissue and in co-culture assays using sporadic as well as HNPCC-derived tumour cell lines. Our data provide strong evidence for an important role of FHL2 in the progression of colon cancers. Tumour-secreted TGF-b1 stimulates FHL2 protein expression in peritumoural fibroblasts, probably facilitating the invasion of tumour glands into the surrounding tissue by enhanced myofibroblast migration and tight connection of fibroblasts to tumour cells via focal adhesions. These findings are absent in HNPCC-associated colon cancers in vivo and may contribute to a less invasive and more protruding tumour margin of microsatellite instable carcinomas. Four and a half LIM domain protein-2 (FHL2) was first identified as a protein differentially expressed in human myoblasts and rhabdomyosarcoma cells, and thus named DRAL (downregulated in rhabdomyosarcoma LIM protein 1 ). FHL2 is a LIM-only protein with four complete and one N-terminal half LIM domains that mediate protein-protein interactions. 2 FHL2 associates with integrin receptors to form focal adhesion contacts and binds signal transducers such as b-catenin. 3-5 Triggered by lipid-induced signalling, such as sphingosine-1-phosphate, FHL2 translocates into the nucleus where it binds several transcription factors including serum response factor, AP1 and androgen receptor and functions as a coactivator or a corepressor to modulate gene expression. [6][7][8] We showed previously that FHL2 is strongly upregulated in mesenchymal cells of wounded skin, and demonstrated a function of FHL2 in myofibroblasts regulating their migration and contraction during cutaneous wound healing. 9 Furthermore, FHL2 is critically involved in matrix assembly allowing migration of cells into the wound area. 10 Analogous to wound healing invasive carcinomas generate a specialised tumour stroma and de...

Epithelial expression of FHL2 is negatively associated with metastasis-free and overall survival in colorectal cancer

“…In our series, fibroblasts within carcinoma tissue also showed FHL2 expression, thereby confirming results from a study specifically investigating FHL2 in peritumoural fibroblasts (Gullotti et al , 2011). In that study, FHL2 expression in peritumoural fibroblasts correlated with lymphatic metastasis in sporadic CRC but not in CRC with mutation in MMR genes; in the present work, we did not study any possible link between MMR protein and FHL2 expression, given the low number of cases in which defective MMR protein expression had been demonstrated.…”

FHL2 Silencing Reduces Wnt Signaling and Osteosarcoma Tumorigenesis In Vitro and In Vivo

“…Few experimental studies suggest that FHL2 may play a role in cancer cell invasion and migration in some soft tissue cancers [32], [47], [48]. However, nothing is known on the role of FHL2 in osteosarcoma cell metastasis capacity.…”

Cancer-Associated Fibroblasts Drive the Progression of Metastasis through both Paracrine and Mechanical Pressure on Cancer Tissue

“…FHL2 interacts with both cytoplasmic and nuclear proteins and has been documented to play a role in modulating various cellular processes, such as cell proliferation, transcription, and signal transduction (109). The authors, additionally observed a positive correlation between TGF-β1 expression in colon cancer cells and FHL2 in peritumoral CAFs, indicating that the recruitment of the latter is most probably tumor dependent (110). …”