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NAD(P)H: quinone oxidoreductase 1 (NQO1) is an antioxidant enzyme which is associated with poor prognosis in human breast, colon, lung and liver cancers. However, the molecular mechanisms underlying the pro-tumorigenic function of NQO1 remains unclear. This study investigated the function of NQO1 in the context of hepatocellular carcinoma (HCC) development. We found that NQO1 was frequently up-regulated in human liver cancer, and its high expression level was correlated with the tumor stage and low survival rate of HCC patients. Loss-of-function of NQO1 inhibited growth in HCC cells with increased apoptosis in vitro, and suppressed orthotopic tumorigenicity in vivo. Mechanistically, high level of NQO1 in HCC cells enhanced protein stability of X-linked inhibitor of apoptosis protein (XIAP) by increasing its phosphorylation at Ser 87. Reintroduction of wile type XIAP and the phospho-mimic mutants XIAPS87D significantly reversed NQO1 knock-down/out induced growth inhibition and apoptosis. In mouse model with orthotopically implanted hepatocarcinoma, NQO1 suppression and NQO1 inhibitor suppressed tumor growth and induced apoptosis. NQO1 plays an important role in sustaining HCC cell proliferation and may thus act as a potential therapeutic target in HCC treatment. [ABSTRACT FROM AUTHOR]

Iron overload is a common pathophysiological state underlying many diseases that has a detrimental influence on cells. The protective effects of Dexmedetomidine (Dex), a high selective alpha-2-adrenoceptor agonist, have been revealed through many experimental models, whereas no study reports its effects on an iron overload model. To elucidate these effects, we used FeCl2 with or without Dex to treat SH-SY5Y cells for 24 h and then detected indicators of oxidative stress, inflammation and apoptosis and investigated possible mechanisms further. After treatment with FeCl2 for 24 h, cell viability decreased in a dose dependent manner, and Dex promoted cell survival in FeCl2 incubation, also in a dose-dependent manner. Compared with the FeCl2 group, 20 µM Dex significantly attenuated ROS accumulation, reduced pro-inflammatory cytokine expression, and inhibited apoptosis. Furthermore, 20 µM concentration of Dex remarkably downregulated the expression of pro-apoptotic protein and activation of caspase 3 while increasing anti-apoptotic protein expression. Additionally, Dex also effectively suppressed the expression of NF-κB and its activation. In conclusion, Dex exerted anti-oxidative stress, anti-inflammation, and anti-apoptosis effects on FeCl2-treated SH-SY5Y cells, possibly by inhibiting NF-κB signaling pathway. [ABSTRACT FROM AUTHOR]

The incidence of cancer is increasing at an alarming rate despite recent advances in prevention strategies, diagnostics and therapeutics for various types of cancer. The identification of novel biomarkers to aid in prognosis and treatment for cancer is urgently required. Uncontrolled proliferation and dysregulated apoptosis are characteristics exhibited by cancer cells in the initiation of various types of cancer. Notably, aberrant expression of crucial oncogenes or cancer suppressors is a defining event in cancer occurrence. Research has demonstrated that SAD1/UNC84 domain protein-2 (SUN2) serves a suppressive role in breast cancer, atypical teratoid/rhabdoid tumors and lung cancer progression. Furthermore, SUN2 inhibits cancer cell proliferation, migration and promotes apoptosis. Recent reports have also shown that SUN2 serves prominent roles in resistance to the excessive DNA damage that destabilizes the genome and promotes cancer development, and these functions of SUN2 are critical for evading initiation of cancer. Additionally, increasing evidence has demonstrated that SUN2 is involved in maintaining cell nuclear structure and appears to be a central component for organizing the natural nuclear architecture in cancer cells. The focus of the present review is to provide an overview on the pharmacological functions of SUN2 in cancers. These findings suggest that SUN2 may serve as a promising therapeutic target and novel predictive marker in various types of cancer. [ABSTRACT FROM AUTHOR]