The Role of Cancer-associated Fibroblasts in Invasive Behavior of Pituitary Adenoma

Objective To determine the role of cancer associated fibroblasts (CAFs) in the invasive behavior of pituitary adenoma. Methods Pituitary adenoma tissues were divided into invasive group (IPA) and non-invasive group (nIPA) according to pre-operative MRI and observations during surgery. Those tissues were cultured and CAFs were identified through α smooth muscle actin (α-SMA). The migratory and invasive ability of CAFs was tested with transwell migration and invasion assay. The expressions of α-SMA and matrix metalloproteinase (MMP)-9 from CAFs were determined by immunocytochemistry and Western blot. Results All cultured CAFs expressed α-SMA. No significant difference in migratory ability of CAFs was found between the IPA and nIPA tissues; however, CAFs from the IPA tissues had stronger invasive ability than those from the nIPA tissues ( P=0.010). Higher levels of MMP-9 expression were found in group IPA as compared with nIPA ( P=0.025). No significant difference in the expression of α-SMA was found between the two groups. Conclusion CAFs may promote invasive behavior by secreting more MMP-9, which may play a part in the invasive behavior of pituitary adenomas.