lnc003875/miR-363/EGR1 regulatory network in the carcinoma -associated fibroblasts controls the angiogenesis of human placental site trophoblastic tumor (PSTT).

The rare gestational trophoblastic neoplasia placental site trophoblastic tumor (PSTT) frequently demonstrates a high degree of vascularization, which may facilitate the tumor metastasis. However, the underlying mechanisms remain largely unknown. In the present study, we found that early growth response 1 (EGR1) was highly expressed in the carcinoma-associated fibroblasts (CAFs) of PSTT tissues. Further data showed that miR-363 down-regulated EGR1 expression whereas long non-coding RNA NONHSAT003875 (lnc003875) up-regulated EGR1 expression in PSTT derived CAFs. lnc003875 exerted no effect on miR-363 expression, but it recovered the decrease of EGR1 caused by miR-363 mimic. The conditioned media from PSTT CAFs treated with miR-363 mimic abrogated the tube formation capacity of human umbilical vein endothelial cells (HUVECs), which can be partially restored by lnc003875 over-expression. Moreover, over-expression of EGR1 promoted the secretion of Angiopoietin-1 (Ang-1) in PSTT derived CAFs and improved the tube formation of HUVECs, which could be effectively abrogated by Ang-1 siRNAs. In vivo vasculogenesis assay demonstrated that lnc003875/EGR1 in PSTT derived CAFs promoted the vasculogenesis of HUVECs in C57BL/6 mice. Collectively, these findings indicated that lnc003875/miR-363/EGR1/Ang-1 in CAFs may be crucial for the angiogenesis of PSTT.