Auranofin Enhances Sulforaphane-Mediated Apoptosis in Hepatocellular Carcinoma Hep3B Cells through Inactivation of the PI3K/Akt Signaling Pathway

The thioredoxin (Trx) system plays critical roles in regulating intracellular redox levels and defending organisms against oxidative stress. Recent studies indicated that Trx reductase (TrxR) was overexpressed in various types of human cancer cells indicating that the Trx-TrxR system may be a potential target for anti-cancer drug development. This study investigated the synergistic effect of auranofin, a TrxR-specific inhibitor, on sulforaphane-mediated apoptotic cell death using Hep3B cells. The results showed that sulforaphane significantly enhanced auranofin-induced apoptosis by inhibiting TrxR activity and cell proliferation compared to either single treatment. The synergistic effect of sulforaphane and auranofin on apoptosis was evidenced by an increased annexin-V-positive cells and Sub-G1 cells. The induction of apoptosis by the combined treatment caused the loss of mitochondrial membrane potential (ΔΨm) and upregulation of Bax. In addition, the proteolytic activities of caspases (-3, -8, and -9) and the degradation of poly (ADP-ribose) polymerase, a substrate protein of activated caspase-3, were also higher in the combined treatment. Moreover, combined treatment induced excessive generation of reactive oxygen species (ROS). However, treatment with N-acetyl-L-cysteine, a ROS scavenger, reduced combined treatment-induced ROS production and apoptosis. Thereby, these results deduce that ROS played a pivotal role in apoptosis induced by auranofin and sulforaphane. Furthermore, apoptosis induced by auranofin and sulforaphane was significantly increased through inhibition of the phosphoinositide 3-kinase (PI3K)/Akt pathway. Taken together, the present study demonstrated that down-regulation of TrxR activity contributed to the synergistic effect of auranofin and sulforaphane on apoptosis through ROS production and inhibition of PI3K/Akt signaling pathway.

A polymorphic minisatellite region of BORIS regulates gene expression and its rare variants correlate with lung cancer susceptibility

Aberrant expression of BORIS/CTCFL (Brother of the Regulator of Imprinted Sites/CTCF-like protein) is reported in different malignancies. In this study, we characterized the entire promoter region of BORIS/CTCFL, including the CpG islands, to assess the relationship between BORIS expression and lung cancer. To simplify the construction of luciferase reporter cassettes with various-sized portions of the upstream region, genomic copies of BORIS were isolated using TAR cloning technology. We analyzed three promoter blocks: the GATA/CCAAT box, the CpG islands and the minisatellite region BORIS-MS2. Polymorphic minisatellite sequences were isolated from genomic DNA prepared from the blood of controls and cases. Of the three promoter blocks, the GATA/CCAAT box was determined to be a critical element of the core promoter, while the CpG islands and the BORIS-MS2 minisatellite region were found to act as regulators. Interestingly, the polymorphic minisatellite region BORIS-MS2 was identified as a negative regulator that repressed the expression levels of luciferase reporter cassettes less effectively in cancer cells compared with normal cells. We also examined the association between the size of BORIS-MS2 and lung cancer in a case–control study with 590 controls and 206 lung cancer cases. Rare alleles of BORIS-MS2 were associated with a statistically significantly increased risk of lung cancer (odds ratio, 2.04; 95% confidence interval, 1.02–4.08; and P=0.039). To conclude, our data provide information on the organization of the BORIS promoter region and gene regulation in normal and cancer cells. In addition, we propose that specific alleles of the BORIS-MS2 region could be used to identify the risk for lung cancer.

Medullary Sponge Kidney Detected in the Pediatric Age

PURPOSE: Medullary sponge kidney (MSK) is a rare congenital disease characterized by diffuse ectasia or dilatation of precalyceal collecting tubules. MSK incidence and prevalence in the general population is uncertain and only a few patients are reported especially in the pediatric age. There has been increasing reports of patients with MSK who have other malformative disorders. Also several case reports concerning about etiological association of some genes. METHODS: Collaborative study through nation-wide survey was done to investigate the incidence and etiological association of some genes such as GDNF gene, ATP6V1B1, ATP6V0A4 gene in developing MSK in Korean children. RESULTS: Four cases of MSK who have various other malformative disorders were collected. There are no mutations of GDNF gene, ATP6V1B1, ATP6V0A4 gene in all patients. CONCLUSION: MSK is one of the very rare diseases in pediatric age. The etiological association of GDNF gene , ATP6V1B1, ATP6V0A4 gene in developing MSK in Korean children is not proved.

Gecko Proteins Exert Anti-Tumor Effect against Cervical Cancer Cells Via PI3-Kinase/Akt Pathway

Anti-tumor activity of the proteins from Gecko (GP) on cervical cancer cells, and its signaling mechanisms were assessed by viable cell counting, propidium iodide (PI) staining, and Western blot analysis. GP induced the cell death of HeLa cells in a dose-dependent manner while it did not affect the viability of normal cells. Western blot analysis showed that GP decreased the activation of Akt, and co-administration of GP and Akt inhibitors synergistically exerted anti-tumor activities on HeLa cells, suggesting the involvement of PI3-kinase/Akt pathway in GP-induced cell death of the cancer cells. Indeed, the cytotoxic effect of GP against HeLa cells was inhibited by overexpression of constituvely active form of Akt in HeLa cells. The candidates of the functional proteins in GP were analyzed by Mass-spectrum. Taken together, our results suggest that GP elicits anti-tumor activity against HeLa cells by inhibition of PI3-kinase/Akt pathway.

Pro-oncogenic potential of NM23-H2 in hepatocellular carcinoma

NM23 is a family of structurally and functionally conserved proteins known as nucleoside diphosphate kinases (NDPK). There is abundant mRNA expression of NM23-H1, NM23-H2, or a read through transcript (NM23-LV) in the primary sites of hepatocellular carcinoma (HCC). Although the NM23-H1 protein is implicated as a metastasis suppressor, the role of NM23-H2 appears to be less understood. Thus, the aim of this study was to examine whether NM23-H2 is associated with hepatocarcinogenesis. The level of NM23-H2 expression in tumor tissues and the surrounding matrix appeared to be independent of etiology and tumor differentiation. Its subcellular localization was confined to mainly the cytoplasm and to a lesser extent in the nucleus. Ectopic expression of NM23-H2 in NIH3T3 fibroblasts and HLK3 hepatocytes showed a transformed morphology, enhanced focus formation, and allowed anchorage-independent growth. Finally, NIH3T3 fibroblasts and HLK3 hepatocytes stably expressing NM23-H2 produced tumors in athymic mice and showed c-Myc over-expression. In addition, NF-kappaB and cyclin D1 expression were also increased by NM23-H2. Lentiviral delivery of NM23-H2 shRNA inhibited tumor growth of xenotransplanted tumors produced from HLK3 cells stably expressing NM23-H2. Collectively, these results indicate that NM23-H2 may be pro-oncogenic in hepatocarcinogenesis.

Genes Associated with Recurrence of Hepatocellular Carcinoma: Integrated Analysis by Gene Expression and Methylation Profiling

Gene expression is suppressed by DNA methylation. The goal of this study was to identify genes whose CpG site methylation and mRNA expression are associated with recurrence after surgical resection for hepatocellular carcinoma (HCC). Sixty-two HCCs were examined by both whole genome DNA methylation and transcriptome analysis. The Cox model was used to select genes associated with recurrence. A validation was performed in an independent cohort of 66 HCC patients. Among fifty-nine common genes, increased CpG site methylation and decreased mRNA expression were associated with recurrence for 12 genes (Group A), whereas decreased CpG site methylation and increased mRNA expression were associated with recurrence for 25 genes (Group B). The remaining 22 genes were defined as Group C. Complement factor H (CFH) and myosin VIIA and Rab interacting protein (MYRIP) in Group A; proline/serine-rich coiled-coil 1 (PSRC1), meiotic recombination 11 homolog A (MRE11A), and myosin IE (MYO1E) in Group B; and autophagy-related protein LC3 A (MAP1LC3A), and NADH dehydrogenase 1 alpha subcomplex assembly factor 1 (NDUFAF1) in Group C were validated. In conclusion, potential tumor suppressor (CFH, MYRIP) and oncogenes (PSRC1, MRE11A, MYO1E) in HCC are reported. The regulation of individual genes by methylation in hepatocarcinogenesis needs to be validated.