[Show abstract][Hide abstract] ABSTRACT: Although hypoxic environments have been known to regulate the migratory ability of bone marrow-derived mesenchymal stem cells (BM-MSCs), which is a critical factor for maximizing the therapeutic effect, the underlying mechanisms remain unclear. Therefore, we aimed to confirm the effect of hypoxia-inducible factor-1α (HIF-1α) on the migration of BM-MSCs and to analyze the interaction between HIF-1α and integrin-mediated signals. Hypoxia-activated HIF-1α significantly increased BM-MSC migration. The expression of integrin α
4 was decreased in BM-MSCs by increased HIF-1α under hypoxia, whereas the expression of Rho-associated kinase 1 (ROCK1) and Rac1/2/3 was increased. After downregulation of HIF-1α by YC-1, which is an inhibitor of HIF-1α, BM-MSC migration was decreased via upregulation of integrin α
4 and downregulation of ROCK1 and Rac1/2/3. Knockdown of integrin α
4 by integrin α
4 siRNA (siITGA4) treatment increased BM-MSC migration by upregulation of ROCK1, Rac1/2/3, and matrix metalloproteinase-2 regardless of oxygen tension. Moreover, siITGA4 treatment increased HIF-1α expression and augmented the translocation of HIF-1α into the nucleus under hypoxia. Taken together, the alternative expression of HIF-1α induced by microenvironment factors, such as hypoxia and integrin α
4, may regulate the migration of BM-MSCs. These findings may provide insights to the underlying mechanisms of BM-MSC migration for successful stem cell-based therapy.
Preview · Article · Jan 2016 · Stem cell International
[Show abstract][Hide abstract] ABSTRACT: Long-term treatment of chronic hepatitis B (CHB) with nucleos(t)ide analogs results in the emergence of drug-resistant hepatitis B virus (HBV) harboring mutations in the polymerase (P) gene. The Phyllanthus extract has anti-HBV activity; however, its antiviral activity against lamivudine (LMV)-resistant mutants has not been examined.
HBV harboring LMV-resistant mutations (rtM204I, rtM204V, and rtM204S) in the P gene at the YMDD ((203)tyrosine-methionine-aspartate-aspartate(206)) reverse transcriptase (RT) active site were generated and their sensitivity to Phyllanthus urinaria koreanis extract examined. Southern blotting and real-time PCR were used to determine the concentration of plant extract required to inhibit HBV DNA synthesis by 50 and 90 % (EC50 and EC90, respectively). An enzyme-linked immunosorbent assay was used to measure the EC50 of HBV surface antigen (HBsAg) and HBV core antigen (HBcAg) secretion, and the 50 % cytotoxic concentration of the extract was measured in a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Real-time RT-PCR was used to measure mRNA expression levels.
The expression of intracellular HBV DNAs in HBV WT- or mutant-transfected HepG2 cells decreased upon treatment with Phyllanthus extract. The secretion of HBsAg and HBcAg also fell in a dose-dependent manner. Phyllanthus extract induced interferon-beta (IFN-β), cyclooxygenase-2 (COX-2), and interleukin-6 (IL-6) mRNA expression in HBV WT-transfected HepG2 cells, possibly via activation of extracellular signal-regulated kinases and c-jun N-terminal kinases and the induction of retinoic acid inducible gene-I, toll-like receptor 3, myeloid differentiation primary response gene 88, and/or tumor necrosis factor receptor-associated factor 6 gene expression. HBV transfection in the absence of extract or exposure of cells to extract alone did not trigger these signaling cascades.
Phyllanthus extract inhibited HBV DNA synthesis and HBsAg and HBcAg secretion by replicating cells harboring HBV wild-type and LMV-resistant mutants, likely by inducing the expression of IFN-β, COX-2, and IL-6. These data indicate that Phyllanthus extract may be useful as an alternative therapeutic agent for the treatment of drug-resistant CHB patients.
Full-text · Article · Jul 2015 · BMC Complementary and Alternative Medicine
[Show abstract][Hide abstract] ABSTRACT: Polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) play important roles in tumor development, progression, and metastasis. Moreover, recent studies have reported that a number of 3′-UTR polymorphisms potentially bind to specific microRNAs in a variety of cancers. The aim of this study was to investigate the association of four MTHFR polymorphisms, 2572C>A [rs4846049], 4869C>G [rs1537514], 5488C>T [rs3737967], and 6685T>C [rs4846048] with colorectal cancer (CRC) in Koreans. A total of 850 participants (450 CRC patients and 400 controls) were enrolled in the study. The genotyping of MTHFR 3′-UTR polymorphisms was performed by polymerase chain reaction-restriction fragment length polymorphism analysis or TaqMan allelic discrimination assay. We found that MTHFR 2572C>A, 4869C>G, and 5488C>T genotypes were substantially associated with CRC susceptibility. Of the potentially susceptible polymorphisms, MTHFR 2572C>A was associated with increased homocysteine and decreased folate levels in the plasma based on MTHFR 677CC. Our study provides the evidences for 3′-UTR variants in MTHFR gene as potential biomarkers for use in CRC prevention.
Full-text · Article · Jun 2015 · Scientific Reports
[Show abstract][Hide abstract] ABSTRACT: Folate has essential roles in DNA synthesis, repair and methylation. Folate metabolism-related gene variants may modulate the levels of this vitamin and affect the cancer risk. Thus, whether these polymorphisms play an important role in carcinogenesis, particularly colorectal cancer (CRC) development, has been a subject interest. The present study investigated the association between polymorphisms in the methylenetetrahydrofolate reductase (MTHFR), thymidylate synthase (TS) and the reduced folate carrier 1 (RFC1) genes and CRC risk. Polymorphisms in MTHFR (677C>T and 1298A>C), TS [1494del6 and the TS enhancer region (TSER)] and RFC1 (-43T>C, 80G>A and 696C>T) were characterized using polymerase chain reaction-restriction fragment length polymorphism in 477 CRC cases and 514 controls. Although no polymorphisms were significantly associated with the CRC risk in the overall sample, significant associations between folate metabolism-related polymorphisms and CRC risk were identified in the stratified analyses. The MTHFR 677CT/1298AC and MTHFR 1298AC+CC/TSER 2R3R genotypes in the presence of plasma folate levels ≤4.12 ng/ml were associated with significantly increased CRC risk. In addition, individuals with the MTHFR 677TT/TSER 3R3R or MTHFR 677/TSER 3R3R/TS 1494 0bp6bp+6bp6bp genotypes and diabetes mellitus (DM) were at an increased risk for CRC. Therefore, the data suggest that i) MTHFR polymorphisms combined with low plasma folate levels and ii) polymorphisms in folate metabolism-related genes combined with metabolic syndrome risk factors (hypertension and DM) increase the odds of developing CRC.
Full-text · Article · Feb 2015 · Molecular and Clinical Oncology
[Show abstract][Hide abstract] ABSTRACT: Background/aimsTransient elastography (TE) has become an alternative to liver biopsy (LB). This study investigated the diagnostic performance of liver stiffness (LS) measurement using TE in Korean patients with chronic hepatitis B and C (CHB and CHC).Methods
From April 2006 to June 2014, 916 patients (567 CHB and 349 CHC) who underwent LB and TE at 15 centers were analyzed. The Batts and Ludwig scoring system was used for histologic assessment. Aspartate aminotransferase (AST)–to–platelet ratio indexes (APRI) were calculated. Area under the receiver operating characteristic curve (AUROC) was used.ResultsThe median age, LS value, and APRI score were 45 years, 8.8 kPa, and 0.61, respectively, in CHB patients versus 51 years, 6.8 kPa and 0.55, respectively in CHC patients. TE was significantly superior to APRI in CHB patients (AUROC 0.774 vs. 0.72 for ≥F2, 0.849 vs. 0.812 for ≥F3, and 0.902 vs. 0.707 for F4, respectively; all P<0.05). Furthermore, TE was significantly superior for predicting ≥ F3 stage (AUROC 0.865 vs. 0.840, P=0.009) whereas it was similar for predicting ≥ F2 and F4 stage (AUROC 0.822 vs. 0.796; 0.910 vs. 0.884; all P>0.05) in CHC patients. In CHB patients, optimal cutoff LS values were 7.8 kPa for ≥ F2, 8.2 kPa for ≥ F3, and 11.6 kPa for F4, versus 6.8 kPa, 8.6 kPa, and 14.5 kPa, respectively, in CHC patients.ConclusionsTE can accurately assess the degree of liver fibrosis in Korean patients with CVH. TE was superior to APRI for predicting each fibrosis stage.This article is protected by copyright. All rights reserved.
No preview · Article · Feb 2015 · Liver international: official journal of the International Association for the Study of the Liver
[Show abstract][Hide abstract] ABSTRACT: Human placental extract (HPE) is a traditional medicine that has been used for the symptomatic treatment of liver disease without any verifying clinical evidence. This study aimed to evaluate the efficacy and safety of HPE in patients with alcoholic or nonalcoholic steatohepatitis (ASH or NASH). We designed this clinical trial as a multicenter, open-label, randomized, comparative noninferiority study to improve the reliability of analyses. The enrollment criteria were limited to ASH or NASH patients with serum alanine aminotransferase (ALT) 1.5-fold higher than the normal level. Patients in the control group were treated with a commercially available mixture of liver extract and flavin adenine dinucleotide (LE-FAD). Intention-to-treat (ITT) analysis was applied to 194 patients, and per-protocol (PP) analysis was available for 154 patients. The rate of primary goal achievement of treatment efficacy was arbitrarily defined as 20% or greater improvement in ALT level compared with the pretreatment level and did not differ significantly between the HPE and control groups [62.9% (44/70) vs. 48.8% (41/84); P = 0.0772]. ITT and modified ITT analysis showed results similar to those of PP analysis. Adverse drug reactions (ADRs) of minimal to moderate degree occurred in 3.1% of patients. The ADR and treatment compliance rates were similar in both groups. In conclusion, the clinical value of HPE in the treatment of ASH and NASH is equivalent to that of LE-FAD.
No preview · Article · Oct 2014 · Biological & Pharmaceutical Bulletin
[Show abstract][Hide abstract] ABSTRACT: Phosphorylation of serines 157, 164, and 172 within the carboxyl-terminal SPRRR motif of the hepatitis B virus (HBV) core (C) protein modulates HBV replication at multiple stages. Threonine 162 and serines 170 and 178, located within the carboxyl-terminal conserved RRRS/T motif of HBV C protein, have been proposed to be protein kinase A phosphorylation sites. However, in vivo phosphorylation of these residues has never been observed, and their contribution to HBV replication remains unknown. In this study, [32P]orthophosphate labeling of cells expressing C proteins followed by immunoprecipitation with anti-HBc antibody revealed that threonine 162 and serines 170 and 178 are phosphoacceptor residues. A triple-alanine-substituted mutant, mimicking dephosphorylation of all three residues, drastically decreased pregenomic RNA (pgRNA) encapsidation, thereby decreasing HBV DNA synthesis. In contrast, a triple-glutamate-substituted mutant, mimicking phosphorylation of these residues, decreased DNA synthesis without significantly decreasing encapsidation. Neither triple mutant affected C protein expression or core particle assembly. Individual alanine substitution of threonine 162 significantly decreased minus-strand, plus-strand, and relaxed-circular DNA synthesis, demonstrating that this residue plays multiple roles in HBV DNA synthesis. Double-alanine substitution of serines 170 and 178 reduced HBV replication at multiple stages, indicating that these residues also contribute to HBV replication. Thus, in addition to serines 157, 164, and 172, threonine 162 and serines 170 and 178 of HBV C protein are also phosphorylated in cells, and phosphorylation and dephosphorylation of these residues play multiple roles in modulation of HBV replication.
Preview · Article · May 2014 · Journal of Virology
[Show abstract][Hide abstract] ABSTRACT: The microRNA (miR)-34 family is a direct transcriptional target of tumor-suppressor TP53 and loss of miR-34 function may impair TP53-mediated cell cycle arrest and apoptosis. In the present study, we investigated whether the single nucleotide polymorphisms (SNPs) rs4938723 (T>C) in the promoter region of miR-34b/c and Arg72Pro (G>C) in codon 72 of TP53 are independently or complementarily associated with the risks and clinical outcomes of colorectal cancer (CRC) and whether the combined effect of these SNPs and metabolic risk factors are related to CRC. We evaluated the SNPs in 545 CRC patients and 428 healthy controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequence analysis. We found that the GC and GC/CC genotypes of TP53 Arg72Pro were associated with decreased risk of CRC (adjusted OR = 0.727 for GC; OR = 0.735 for GC/CC). The combined genotypes of TT-GC and CC-GG were significantly associated with reduced CRC risk (adjusted OR = 0.628 for TT-GC; OR = 0.381 for CC-GG, respectively). The SNP rs4938723 and diabetes mellitus (DM) together were associated with an increased CRC risk, but the SNP TP53 Arg72Pro CC with DM showed a protective effect against CRC. These findings indicate that rs4938723 in the promoter region of pri-miR-34b/c and the SNP in TP53 codon 72 were related to decreased risk of CRC in the population studied and those metabolic diseases and genetic variants influence each other with regard to CRC susceptibility.
[Show abstract][Hide abstract] ABSTRACT: The differential diagnosis between inactive carrier and active hepatitis is important in patients with chronic hepatitis B (CHB) virus infection. Serum cytokeratin (CK)-18 fragments (M30-antigen) are proposed as biomarkers of apoptosis.
We investigated whether serum M30-antigen levels might help to characterize the various phases of CHB and predict the state of significant inflammation in patients with CHB.
A total of 339 CHB patients who underwent liver biopsy, were included. Serum M30-antigen levels were compared between inactive carriers (n=21), patients with HBeAg-negative hepatitis (n=95), HBeAg-positive hepatitis (n=141) and liver cirrhosis (n=82).
Serum M30-antigen levels were correlated significantly not only with AST (r=0.544, p<0.001) and ALT (r=0.315, p<0.001) and but also inflammatory grading score on liver biopsy (r=0.240, p<0.001). Serum M30-antigen level in HBeAg-negative CHB was significantly higher than that of inactive HBV carrier (399.78U/L vs 148.90U/L, p<0.001). Multivariate analysis showed that AST (p<0.001), albumin (p=0.009) and M30-antigen (p=0.020) were the independent predictors of significant inflammation. Combined serum M30-antigen level (>344U/L) and AST (>78IU/L) measurement provided the most accurate identification of significant inflammation, showing 38.2% sensitivity, 96.1% specificity, 91.0% positive predictive value and 56.1% negative predictive value.
Serum M30-antigen can be a predictive marker for distinguishing between inactive carrier and HBeAg-negative CHB. Serum M30 levels are associated with the presence of significant inflammation, especially in patients with normal or minimally elevated ALT in CHB patients.
Preview · Article · Oct 2013 · Journal of clinical virology: the official publication of the Pan American Society for Clinical Virology
[Show abstract][Hide abstract] ABSTRACT: 5-Fluorouracil (5-FU) is a cornerstone of chemotherapy for colorectal cancer (CRC), and the major targets of 5-FU are thymidylate synthase (TS), methylenetetrahydrofolate reductase (MTHFR), and reduced folate carrier 1 (RFC1). We hypothesized that polymorphisms in the genes encoding these proteins would be associated with CRC patient survival. Patients and methods We genotyped the following polymorphisms in 372 CRC patients: TS enhancer region (TSER), TS 1494del6, MTHFR 677C>T and 1298A>C, and RFC1 -43T>C, 80G>A, and 696C>T. Using Kaplan-Meier curves, log-rank tests, and Cox proportional hazard models, we evaluated associations between these polymorphisms and overall survival (OS).
The combined TS 1494 0bp6bp+6bp6bp genotype was associated with reduced OS compared to the TS 1494 0bp0bp genotype. Among rectal cancer patients, the RFC1 -43CC and 80AA genotypes were associated with favorable OS.
Our data suggest that TS and RFC1 polymorphisms are associated with CRC prognosis in Korean patients. Further studies are needed to verify these findings.
[Show abstract][Hide abstract] ABSTRACT: Occult HBV infection (OBI) is defined as presence of HBV DNA in the liver tissue in patients with serologically undetectable HBsAg. There are differences in virologic and serological profiles of OBI. Majority of OBI are positive for anti-HBs and/or anti-HBc and minor portion are negative for all HBV markers. However, there are no HBV mutations in the surface and its regulatory regions. HBV infection persists by the presence of covalently closed circular DNA (cccDNA) within the infected hepatocytes, which serves as a reservoir for future infection. OBI increases the risk of HBV transmission through transfusion, hemodialysis, and organ transplantation. Therefore effective measures should be employed to screen OBI. Antiviral therapy is needed in HBsAg-negative transplant patients who are anti-HBc positive to prevent the recurrence of HBV infection. Since HBV replication is strongly suppressed by immune surveillance system in OBI patients, immunosuppression results in massive HBV replication. This leads to acute hepatitis and sometimes mortality when immune surveillance is recovered after stopping immunosuppressive drugs/anticancer chemotherapy. Therefore, narrow surveillance is required to recognize the viral reactivation and start antiviral agents during immunosuppressive therapy/anticancer chemotherapy in patients with OBI. (Korean J Gastroenterol 2013;62:148-153).
Preview · Article · Sep 2013 · The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi
[Show abstract][Hide abstract] ABSTRACT: Although much advancement has been achieved in the treatment of chronic hepatitis B, antiviral resistance is still a challenging issue. Previous generation antiviral agents have already developed resistance in a number of patients, and it is still being used especially in resource limited countries. Once antiviral resistance occurs, it predisposes to subsequent resistance, resulting in multidrug resistance. Therefore, prevention of initial antiviral resistance is the most important strategy, and appropriate choice and modification of therapy would be the cornerstone in avoiding treatment failures. Until now, management of antiviral resistance has been evolving from sequential therapy to combination therapy. In the era of tenofovir, the paradigm shifts again, and we have to decide when to switch and when to combine on the basis of newly emerging clinical data. We expect future eradication of chronic hepatitis B virus infection by proper prevention and optimal management of antiviral resistance.
[Show abstract][Hide abstract] ABSTRACT: Metabolic syndrome, comprising diabetes, hypertension, central obesity, and dyslipidemia, is increasingly prevalent worldwide. We aimed to study the relationship between metabolic syndrome and the risk of liver fibrosis in patients with chronic hepatitis B (CHB) and chronic hepatitis C (CHC).
In total, 954 patients (CHB, 850; CHC, 104 patients) with liver biopsy were included in the retrospective analysis. Extensive clinical and histological data were available. Metabolic syndrome was defined using the International Diabetes Federation definition of metabolic syndrome, 2006 criteria. Histological lesions were evaluated according to the histology activity index system.
Metabolic syndrome was present in 6% of patients and significantly more prevalent in patients with CHC than in patients with CHB (5% vs 13%, p<0.001). Patients with metabolic syndrome were older among patients with CHB and patients with CHC, and, as expected, were mainly overweight or obese. Fibrosis was significantly more severe in patients with metabolic syndrome than in those without, regardless of whether they had CHB and CHC (CHB, 3.3±2.1 vs 2.4±1.3, p=0.025; CHC, 2.6±1.5 vs 1.3±0.7, p=0.006). Liver fibrosis (stages 3 to 4) was independently associated with increased age, higher transaminase level and metabolic syndrome (odds ratio, 2.421; p=0.017).
Metabolic syndrome is associated independently with severe fibrosis in patients with chronic viral hepatitis B and C.
[Show abstract][Hide abstract] ABSTRACT: Hepatitis B core antigen is known to be a major target for virus-specific T cells and also reflects the progression of liver dissease and viral replication. Hepatitis B core antigen expression in hepatocytes leads to altered histological activity, viral replication, and immune response. The purpose of this study is to evaluate whether the topographical distribution of hepatitis B core antigen expression can predict the viral response to entecavir in patients with chronic hepatitis B.
We enrolled 91 patients with treatment-naïve chronic hepatitis B. All the patients underwent liver biopsy, and the existence and pattern of hepatitis B core antigen evaluated by immunohistochemistry. All patients received 0.5 mg of entecavir daily following a liver biopsy. We checked the viral response at 3, 6, and 12 months during antiviral therapy.
Of the 91 patients, 64 (70.3%) had hepatitis B core antigen expression. Of the subcellular patterns, the mixed type was dominant (n=48, 75%). The viral response was significantly higher in the hepatitis B core antigen-negative group than in the hepatitis B core antigen-positive group (88.9% and 54.7%, respectively; p=0.001) after 12 months of entecavir therapy.
Chronic hepatitis B patients who are hepatitis B core antigen-negative have a better response to entecavir therapy than do hepatitis B core antigen-positive patients.