Lcn2 was preferentially expressed in well-differentiated HCC versus liver cirrhosis tissues, and its expression was positively correlated with the stage of HCC. The characteristics of EMT were reversed by adenoviral transduction of Lcn2 into SH-J1 cells, including the down-regulation of N-cadherin, vimentin, alpha-smooth muscle actin, and fibronectin, and the concomitant up-regulation of CK8, CK18, and desmoplakin I/II. Knockdown of Lcn2 by short hairpin RNA (shRNA) in HKK-2 cells expressing high levels of Lcn2 was associated with EMT. Epidermal growth factor (EGF) or transforming PLX4032 purchase growth factor beta1 (TGF-β1) treatment resulted in down-regulation of Lcn2,

accompanied by an increase in Twist1 expression and EMT in HCC cells. Stable Lcn2 expression in SH-J1 cells reduced Twist1 expression, inhibited cell proliferation and invasion in vitro, and suppressed tumor growth and metastasis in a mouse model. Furthermore, EGF or TGF-β1 treatment barely changed EMT marker expression in SH-J1 cells ectopically expressing Lcn2. Ectopic expression of Twist1 induced EMT marker expression even in cells expressing Lcn2, indicating that Lcn2 functions downstream of growth factors and upstream of Twist1. Conclusion: Together, our findings indicate that Lcn2 can negatively modulate the EMT in HCC cells through an EGF (or TGF-β1)/Lcn2/Twist1 pathway. Thus, Lcn2 may be a candidate metastasis

suppressor and a potential therapeutic target in HCC. (Hepatology 2013;58:1349–1361) Lipocalin-2 (Lcn2), also known as NGAL, belongs to the RXDX-106 lipocalin protein family and was first purified from human neutrophils because of its association with gelatinase.[1] Lcn2 can exist as a 25-kDa monomer, 46-kDa disulfide-linked homodimer, and/or 135-kDa disulfide-linked heterodimer with neutrophil

gelatinase.[2] Elevated Lcn2 expression has been observed in multiple human cancers including breast, colorectal, and ovarian cancers; however, the biological roles of elevated Lcn2 in cancer cells are not yet clear.[3-5] Substantial data indicate that Lcn2 is involved in invasion and metastasis. Lcn2 is able to facilitate gastrointestinal Metalloexopeptidase mucosal regeneration by promoting cell migration.[6] In breast cancer, Lcn2 expression is considered to be a poor prognostic marker and is associated with tumor cell invasiveness. Its overexpression has been shown to increase cell migration, invasion, and lung metastasis in 4T1 murine breast cancer cells.[7, 8] However, other studies reported that Lcn2 suppressed cellular invasion and metastases in colon cancer and in Ras-transformed mouse mammary cells in vitro.[9, 10] Recently, Lcn2 was also shown to suppress invasion and angiogenesis in pancreatic cancer.[11] Consistent with results from these previous studies, Lcn2 expression in ovarian cancer blocked the epithelial-to-mesenchymal transition (EMT), one of the hallmarks of invasive neoplasia.