Nucleus accumbens associated 1 is recruited within the promyelocytic leukemia nuclear body through SUMO modification.

Nucleus accumbens associated 1 (NACC1) is a cancer-associated BTB/POZ (pox virus and zinc finger/bric-a-brac tramtrack broad complex) gene, and is involved in several cellular functions in neurons, cancer and stem cells. Some of the BTB/POZ proteins associated with cancer biology are SUMOylated, which appears to play an important role in transcription regulation. We show that NACC1 is SUMOylated on a phylogenetically conserved lysine (K167) out of three consensus SUMOylation motif sites. Amino acid substitution in the SIM sequence (SIM/M) within the BTB/POZ domain partially reduced K167 SUMOylation activity of NACC1. Overexpression of GFP-NACC1 fusion protein leads to formation of discrete nuclear foci similar to promyelocytic leukemia nuclear bodies (PML-NB), which colocalized with SUMO paralogues (SUMO1/2/3). Both NACC1 nuclear body formation and colocalization with SUMO paralogues were completely suppressed in the GFP-NACC1-SIM/M mutant, whereas they were partially maintained in the NACC1 K167R mutant. Confocal immunofluorescence analysis showed that endogenous and exogenous NACC1 proteins colocalized with endogenous PML protein. A pull-down assay revealed that the consensus motifs of the SUMO acceptor site at K167 and the SIM within the BTB/POZ domain were both necessary for efficient binding to PML protein. Our study demonstrates that NACC1 can be modified by SUMO paralogues, and cooperates with PML protein.

Alpha-fetoprotein: A biomarker for the recruitment of progenitor cells in the liver in patients with acute liver injury or failure.

AIM: The optimal conditions for hepatocyte proliferation should be clarified in an attempt to improve the impaired liver regeneration observed in patients with acute liver failure (ALF). In order to evaluate the significance of the serum α-fetoprotein (AFP). level and prothrombin time international normalized ratio (PT-INR) as possible biomarkers of the proliferation of liver stem/progenitor cells (LPC) and mature hepatocytes (MH), respectively, we focused on donors of living donor liver transplantation (LDLT) and patients with acute liver injury (ALI), including ALF. METHODS: Seventy-three patients with ALI/ALF and 11 donors for LDLT were evaluated. LPC induction was histologically evaluated using cytokeratin (CK)-7 staining in 45 ALI/ALF patients. RESULTS: The AFP level was not apparently elevated during the observation period in any of the LDLT donors, whereas the serum AFP levels were substantially increased in the patients with ALI/ALF and significantly correlated with the number of CK-7 positive LPC in the liver, except for very severe damaged liver. All patients exhibiting an early peak in the AFP level prior to PT-INR elevation died. CONCLUSION: The serum AFP level may reflect the induction of LPC in ALI/ALF patients. The substantial and persistent induction of LPC until sufficient regeneration of MH may be needed for a recovery from ALF. We herein demonstrate that the serum AFP level may be a serum marker of LPC in patients with ALI/ALF. A comparison of the serial changes in the AFP levels and PT-INR in our study patients showed impaired proliferation of LPC and delayed recovery of MH in the patients who died.

A disintegrin and metalloproteinase 17 (ADAM17) mediates epidermal growth factor receptor transactivation by angiotensin II on hepatic stellate cells.

AIMS: Epidermal growth factor receptor (EGFR) transactivation induced by angiotensin II (Ang II) participates in the progression of various diseases. A disintegrin and metalloproteinase 17 (ADAM17) is thought to promote renal fibrosis, cardiac hypertrophy with fibrosis and atherosclerosis by activation of the EGFR through secretion of EGFR ligands. The purpose of this study was to investigate whether Ang II-induced EGFR transactivation occurs on hepatic stellate cells (HSCs) and whether the reaction is mediated via ADAM17. MAIN METHODS: Ang II-induced EGFR transactivation and cellular proliferation of the human HSC line LI90 were investigated using Western blotting and ATP assay, respectively. Ang II-induced secretion of mature amphiregulin into the cell culture medium was evaluated by enzyme-linked immunosorbent assay (ELISA). KEY FINDINGS: An inhibitor of ADAM17, TAPI-1, as well as antagonists of EGFR and angiotensin II type-1 receptor (AT1), attenuated Ang II-induced EGFR transactivation and proliferation of LI90 cells. Furthermore, silencing of ADAM17 inhibited Ang II-induced secretion of mature amphiregulin in addition to EGFR transactivation. SIGNIFICANCE: These results indicate that ADAM17 mediates Ang II-induced EGFR transactivation on HSCs, and that this process may participate in the progression of liver fibrosis.

Nucleus accumbens-associated 1 contributes to cortactin deacetylation and augments the migration of melanoma cells.

We investigated the prognostic significance and post-transcriptional acetylation-modification of cortactin (CTTN) via the nucleus accumbens-associated 1 (NACC1)-histone deacetylase 6 (HDAC6) deacetylation system in primary melanomas and melanoma cell lines. Overexpression of CTTN protein was observed in 56 (73%) of 77 stage I-IV melanomas, and was significantly correlated with tumor thickness, lymph node metastasis, distant metastasis, and disease outcome. The patients whose tumors exhibited CTTN overexpression had a poorer outcome than patients without this feature (P=0.028, log-rank test). NACC1 and CTTN proteins, but not HDAC6, were overexpressed in four melanoma cell lines in comparison with a primary culture of normal human epidermal melanocytes. Knockdown of both NACC1 and HDAC6 markedly downregulated the migration activity of all melanoma cell lines (P<0.05), and induced a gain of CTTN protein acetylation status. Confocal microscopy showed that hyperacetylation of CTTN modulated by depletion of both NACC1 and HDAC6 induced disappearance of CTTN protein at the leading edge of migrating cells, resulting in stabilization of the focal adhesion structure and development of actin stress fibers. These data suggest that the acetylation status of CTTN modulated by the NACC1-HDAC6 deacetylation system induces acceleration of melanoma cell migration activity via an actin-dependent cellular process, possibly contributing to aggressive behavior (invasion/metastasis) of the melanoma cells.

Carnosic acid prevents obesity and hepatic steatosis in ob/ob mice.

AIM: Carnosic acid (CA) inhibits adipogenesis in vitro. The present study evaluated the therapeutic effects of CA in ob/ob mice. METHODS: The experimental animals were given a standard chow diet with or without CA for 5 weeks. Bodyweight gain and food intake were measured during this period. Magnetic resonance imaging analysis, histological examination, serum chemistry analysis and intraperitoneal glucose tolerance test (IPGTT) were all performed. RESULTS: The mice fed CA experienced significant weight loss and reduced visceral adiposity, in addition to significantly reduced serum triglyceride (TG) and cholesterol levels. Importantly, CA had a dramatic effect on the liver by reducing the hepatic TG content, thus decreasing serum alanine aminotransferase levels. In addition, IPGTT revealed that CA significantly improved glucose tolerance. CONCLUSION: These data suggest that CA is a novel therapeutic agent for obesity-related non-alcoholic fatty liver disease.

Detection of human papillomavirus in a urothelial carcinoma mimicking urethral caruncle.

Primary carcinoma of the female urethra is an uncommon diagnosis, accounting for less than 0.02% of all carcinomas in women. Urothelial carcinomas occupying the distal urethra in young females are considered to be extremely rare. Here we report what we believe to be the sixth case of primary urothelial carcinoma in the published English-language literature. The patient, a 26-year-old woman, presented with a distal urethral lesion that resembled a caruncle, but which was proved to be a urothelial carcinoma on histopathological examination of the resected specimen. Human papillomavirus type 51 DNA was detected in the tumor by polymerase chain reaction and in situ hybridization. These findings suggest that human papillomavirus might be involved in a subset of urothelial carcinomas of the urethra.

Non-invasive evaluation of liver fibrosis using acoustic radiation force impulse imaging in chronic hepatitis patients with hepatitis C virus infection.

BACKGROUND/AIMS: Acoustic radiation force impulse (ARFI) imaging is a new technology for performing liver elastography. However, use of this technique to estimate the degree of fibrosis in chronic liver disease (CLD) related to hepatitis C virus (HCV) infection has not yet been established. We evaluated the validity, accuracy and flexibility of the ARFI method in CLD. METHODOLOGY: Subjects comprised 30 patients with chronic hepatitis (CH), 30 patients with liver cirrhosis (LC) and 10 healthy subjects (controls). All patients had HCV infection. Elastography of the liver was performed at different sites using the ARFI method. Relationships between shear wave velocity (SWV) obtained by ARFI, clinical diagnosis, serum parameters of liver function and fibrosis in the liver were evaluated. Moreover, cut-off values for differential diagnosis between CH and LC were estimated using area under the receiver operating characteristics (AUROC). RESULTS: Mean SWV (+/- standard deviation) was 2.67 +/- 1.18 m/s, 1.33 +/- 0.54 m/s and 0.99 +/- 0.21 m/s in the LC, CH and control groups, respectively. SWV was significantly higher in the LC group than in the CH and control groups (p < 0.0001), and in the CH group than in the control group (p = 0.0023). SWV in each stage of fibrosis was 1.09 +/- 0.22 m/s in F0-1, 1.24 +/- 0.52 m/s in F2, 1.61 +/- 0.79 m/s in F3, and 2.35 +/- 1.11 m/s in F4. SWV correlated significantly with serum total bilirubin, alanine aminotransferase, cholesterol, albumin, platelet counts, prothrombin time, fibrosis markers, hyaluronic acid and type IV collagen. A steady stepwise increase in elasticity correlated significantly with severity of hepatic fibrosis (p = 0.9772; p = 0.002). Diagnostic ability for LC was superior in ARFI (AUROC, 0.930 in ARFI; 0.846 in aspartate aminotransferase to platelet ratio index; 0.829 in Forns' index; and 0.785 in platelet count). CONCLUSIONS: ARFI is extremely useful for distinguishing between CH and LC, and SWV might correlate significantly with degree of progression in CLD with HCV infection.

DNA hypomethylation at the CpG island is involved in aberrant expression of the L1 cell adhesion molecule gene in colorectal cancer.

The L1 cell adhesion molecule (L1CAM) has been identified as a target gene of beta-catenin-TCF signaling in colorectal cancer (CRC) and associated with aggressive tumor behavior such as invasion and metastasis. We investigated the methylation status at the L1CAM gene promoter and/or L1CAM mRNA/protein expression in 4 CRC cell lines and 71 primary CRCs. Aberrant L1CAM expression was immuno histochemically observed in 31 (43.7%) of 71 cases, and correlated with advanced stage and presence of lymph node and distant metastases (P<0.05). Treatment with a demethylating agent induced L1CAM mRNA/protein expression in two cell lines lacking L1CAM expression. Bisulfite-modified genome sequencing suggested that DNA methylation status at core promoter and putative TCF-binding sites within the L1CAM promoter was correlated with L1CAM mRNA/protein expression in 4 CRC cell lines. Using the crypt isolation followed by bisulfite-modified genome sequencing and methylation-specific PCR methods, we confirmed that the DNA hypomethylation at core promoter and putative TCF-binding sites was well correlated with the aberrant L1CAM protein expression in primary CRC samples. These results suggest that DNA hypomethylation at the L1CAM CpG islands might induce L1CAM aberrant expression and contribute to the acquisition of aggressive tumor behavior in CRC.