TIPE1 function as a prognosis predictor and negative regulator of lung cancer.

TIPE1 (tumor necrosis factor-α-induced protein 8-like 1 or TNFAIP8L1) belongs to the TIPE (TNFAIP8) family, which act as a regulator of cell death. However, the expression and biologic functions of TIPE1 in lung cancer are largely unknown. Here, we investigated the roles of TIPE1 in lung cancer. Evaluated by qRT-PCR and immunohistochemical staining, lower TIPE1 mRNA and protein expression was found in the lung tumor tissue, compared with adjacent non-tumor tissues, which positively correlated with tumor patient survival. Overexpression of TIPE1 by lentivirus system in TIPE1-downregulated lung cancer cells significantly diminished cell growth and colony formation, companied with proliferation inhibition, apoptosis induction and invasion inhibition. It was identified to be due to TIPE1-regulated Cyclin D1, Cyclin B1, caspase 8, Caspase3, MM2 and MMP9 expression. Consistently, using a homograft tumor model in Balb/c mice, we discovered that TIPE1 prevented the growth and tumor weight of murine lung cancer homografts. Our findings revealed the anti-tumor role of TIPE1 in lung cancer cells and TIPE1 might be a novel prognostic indicator for lung cancer patients.