Lipocalin-2 Induces Apoptosis in Human Hepatocellular Carcinoma Cells Through Activation of Mitochondria Pathways

Abstract

Lipocalin 2 (LCN2) is a secreted, iron-binding glycoprotein that is abnormally expressed in some malignant human cancers. However, the roles of LCN2 in hepatocellular carcinoma (HCC) cells are unknown. In this study, we suggested the LCN2 and LCN2R were weak detected in the HCC cell lines, LCN2 and LCN2R were found to be down-regulated in tumor tissues in 16 HCC patients. MTT, DAPI, TUNEL, and flow cytometry analyses revealed that LCN2 overexpression dramatically inhibited cell viability, induced apoptosis features of cell-cycle arrest in sub-G1 phase, in DNA fragmentation, and in condensation of chromatin in Huh-7 and SK-Hep-1 cells. Western blots were used to detect the activation of caspase, pro-apoptosis, and anti-apoptosis protein expression in overexpress-LCN2 HCC cells. LCN2-induced apoptosis was characterized by cleavage of caspase-9, -8, -3, and PARP protein, and a reduction in the mitochondrial membrane potential (MMP). Furthermore, LCN2 also enhanced the down-regulated Bcl-2 and up-regulated the expression of Bax. In addition, our experiments with caspase inhibitors LEHD-FMK and IETD-FMK prevent LCN2-induced apoptosis. We also demonstrated that treatment of overexpress-LCN2 HCC cells with the LCN2 neutralized antibody also significantly attenuated LCN2-induced cell apoptosis. These findings indicate that LCN2 overexpression can effectively induce apoptosis of HCC cells and may be used as a potent therapy against human HCC.

Enhancement of ionizing radiation response by histamine in vitro and in vivo in human breast cancer

“…27 Lcn-2 is a member of the lipocalin superfamily, with diverse functions, including the induction of apoptosis, and is abnormally expressed in some malignant human cancers. [28][29][30] Previous studies indicated that the expression of Lcn-2 is induced under harmful conditions, where production of free radicals has been reported, and that it could be a useful biomarker for the detection of oxidative stress. Results show that histamine and H 1 R agonist increased apoptosis and ROS levels while upregulated Lcn-2 expression in non-irradiated and irradiated MDA-MB-231 cells.…”

Methanolic extract of white asparagus shoots activates TRAIL apoptotic death pathway in human cancer cells and inhibits colon carcinogenesis in a preclinical model

“…Bioactive asparagus constituents such as saponins or fructooligosaccharides are well recognized as potent immune stimulators (50,51). These effects might be in part modulated by DEF-5 and LCN2 (38,52), which are considered as active weapons against several cancer cell types (53). Furthermore, an impaired expression of DEF-5 and LCN2 and the over-production of the pro-inflammatory cytokine IL1β have been closely associated with inflammatory bowel disease (54–56).…”

Lipocalin 2 in the pathogenesis of fatty liver disease and nonalcoholic steatohepatitis

“…In addition, the expression of both LCN2 and its receptor (LCN2R) were found to be downregulated in tumor tissues derived from 16 patients suffering from HCC [96]. Most interestingly, this report discovered for the first time that LCN2 when overexpressed in HCC cell lines significantly increased cell apoptosis and inhibited cell viability through activation of mitochondria pathways, while LCN2 neutralizing antibodies effectively attenuated apoptosis in respective cells [96].…”

“…Most interestingly, this report discovered for the first time that LCN2 when overexpressed in HCC cell lines significantly increased cell apoptosis and inhibited cell viability through activation of mitochondria pathways, while LCN2 neutralizing antibodies effectively attenuated apoptosis in respective cells [96]. Based on these findings, the authors concluded that targeting and overexpression of LCN2 might be a potent therapy for the treatment of human HCC [96].…”