Gamma smooth muscle actin as a new potential marker of cancer-associated fibroblasts

Abstract

Cancer-associated fibroblasts (CAFs) represent an important component of the cancer ecosystem, influencing the broad scale of biological properties of tumour cells, including the capacity for metastasis formation. An important CAF subpopulation, known as myCAFs, typically expresses alpha-smooth muscle actin. Transcriptomic analysis demonstrated that activated fibroblasts isolated from various pathological tissues also express the ACTG2 gene encoding gamma-smooth muscle actin. This was further validated by immunocytochemistry. Using the scratch test in vitro, it was possible to demonstrate that gamma-smooth muscle actin may be associated with the epithelial-mesenchymal transition, which was also shown by transcriptomic analysis. The presence of gamma-smooth muscle actin-positive fibroblasts in histopathological sections of human tumours verified the expression of this protein as a new potential marker of CAFs.