Twisted Gastrulation BMP Signaling Modulator 1 Regulates Papillary Thyroid Cancer Cell Motility and Proliferation

: Bone morphogenetic proteins (BMPs) are growth factors that have important functions in cell proliferation, migration and differentiation. To date, BMP pathway activation has been found in multiple human tumors and is associated with enhanced malignant tumor growth and metastasis. BMP activity is tightly regulated by a family of soluble extracellular secreted BMP modulators. Twisted gastrulation BMP signaling modulator 1 (TWSG1) is a direct BMP regulator that is required for the full signaling activity of BMPs. However, the functions and mechanisms of TWSG1 in papillary thyroid cancer (PTC) metastasis have not been reported. TWSG1 expression was detected in 44 PTC tissues with lymph node metastasis (LNM) and 56 PTC tissues without LNM using quantitative real-time polymerase chain reaction (qRT-PCR). Gain- and loss-of-function approaches were used to assess the biological function of TWSG1 in PTC cells. Matrigel assays demonstrated the effect of tumor cell-derived TWSG1 on endothelial cell function. Our results showed that TWSG1 expression was significantly enhanced in PTC with LNM compared to that in PTC without LNM. TWSG1 knockdown inhibited migration, invasion and proliferation of PTC cells. Additionally, TWSG1 suppression impaired the tumor cell-induced endothelial cell sprout formation. We found that TWSG1 signaling may be transduced by the BMP target transcription factor inhibitor of DNA binding 1 (Id1) and matrix metalloproteinases (MMPs) 2 and 9. In conclusion, TWSG1 was highly expressed in metastasized PTC; tumor growth, migration and invasion were dependent on TWSG1, and it may be a new diagnostic and therapeutic target for PTC.