Tamoxifen Regulates Epithelial-Mesenchymal Transition in Endometrial Cancer via the CANP10/NRP1 Signaling Pathway.

Tamoxifen, which is used to treat advanced gynecological tumors, has been associated with tumor cell metastasis. Herein, we investigated the effect of tamoxifen on epithelial-mesenchymal transition in endometrial cancer and the associated signaling mechanism. Wound healing and invasion chamber assays, respectively, were performed to determine the migrative capacity and invasiveness of tamoxifen-stimulated endometrial carcinoma (RL95-2) cells. Western blotting and immunofluorescence were used to evaluate the expression of vimentin, E-cadherin, calpain 10 (CANP10), and neuropilin-1 (NRP1). Transfection of a CAPN10-harboring plasmid was used to overexpress CANP10 in RL95-2 cells, and small interfering RNAs were used to silence CANP10 and NRP1 expression. Tamoxifen induced migration, invasion, and morphological changes in RL95-2 cells. It also downregulated E-cadherin expression and upregulated vimentin, CANP10, and NRP1 expression. CANP10 silencing inhibited tamoxifen-induced NRP1 upregulation, and CANP10 or NRP1 silencing inhibited the migration and invasion of RL95-2 cells. CANP10 overexpression upregulated vimentin expression and downregulated that of E-cadherin and also increased cell migration and invasion. Silencing NRP1 protein expression inhibited the induction effect of CANP10 overexpression. In conclusion, tamoxifen promotes the epithelial-mesenchymal transition of RL95-2 cells via the CANP10/NRP1 signaling pathway. Thus, targeting CANP10 or NRP1 may be a novel strategy for preventing tamoxifen-induced endometrial cancer metastasis.