Background and purpose: Abnormal expression and amplification of transforming growth factor beta 1 (TGF-β1) and Notch3 in ovarian carcinoma tissues are associated with metastasis and low survival rate

respectively. The crosstalk between TGF-β1 and Notch3 signaling pathway promotes invasion and metastasis in various cancers. However

the mechanism is still under debate. Therefore

this study was designed

using in vitro cytological assays

to investigate the effects of TGF-β1 and Notch3 signaling pathway on ovarian cancer cell biological behavior and the potential mechanisms in terms of the crosstalk between TGF-β1 and Notch3 signaling pathway. Methods: Hey A8 and Hey cell lines were used as models in the study. The levels of TGF-β1 in supernatants from culture media were measured by ELISA. Both cell lines were treated with 500 ng/mL TGF-β1 neutralizing antibody (control group)

10 ng/mL TGF-β1

50 μmol/L DAPT

10 ng/mL TGF-β1 and 50 μmol/L DAPT

50 μmol/L tumor necrosis factor receptor-associated factor 6 (TRAF6) peptide inhibitor

10 ng/mL TGF-β1 and 50 μmol/L TRAF6 peptide inhibitor

respectively. The protein expression levels of TGF-β1 and Notch3 signaling pathway molecules as well as TRAF6 from cell lines with different treatments were detected by Western blot. Cell proliferation

migration and invasion were tested by cell counting kit-8 (CCK-8)

scratch and Transwell assays

respectively. Results: The levels of TGF-β1 were timedependently increased in supernatants of culture media from Hey A8 and Hey cell lines. Compared with control group

TGF-β1 treatment increased the expression levels of Notch3-ICD and Hes1

while no obvious change was observed in the group treated with DAPT and TGF-β1. Moreover

TGF-β1 promoted cell proliferation

migration and invasion while DAPT decreased the proliferation

migration and invasion in cell lines treated with TGF-β1. These results indicated that TGF-β1 might promote proliferation

invasion and migration of ovarian epithelial cancer cells through activating the Notch3 signaling pathway. Further study showed that TGF-β1 up-regulated TRAF6 and activated the Notch3 signaling pathway. The activation of the Notch3 signaling pathway by TGF-β1 was inhibited in cells treated with the TRAF6 specific inhibitor. Conclusions: TGF-β1 may promote the proliferation

invasion and migration of ovarian epithelial carcinoma cells through TRAF6-mediated activation of the Notch3 signaling pathway.