Biomedical subjects

Hirohito Tsubouchi

Publications and source records attributed to Hirohito Tsubouchi.

At least 19 recordsLinked to original sources

PubMed2006

Alanine aminotransferase level as a predictor of hepatitis C virus-associated hepatocellular carcinoma incidence in a community-based population in Japan.

We evaluated the utility of alanine aminotransferase (ALT) measurements in predicting the incidence of hepatocellular carcinoma (HCC) in a cohort of 667 adults with chronic hepatitis C virus (HCV) infection from a community-based population in Japan, between 1994 and 2003. Cox proportional hazards regression analysis was used to describe the relationship between prediagnostic levels of ALT and the rate of HCC, after adjusting for age and gender; hazard ratios (HRs) and 95% confidence intervals (CIs) were obtained. Over an average of 8 years of follow-up, 52 HCC cases were identified. A significant association between a 20 IU/L difference in higher ALT level and subsequent HCC incidence was observed (HR = 1.2; 95% CI: 1.1, 1.3). An abnormal ALT level (> or =35 IU/L) increased the HCC rate by 4-fold compared to a normal ALT level (HR = 4.1; 95% CI: 2.1, 8.0). Among 551 subjects with at least 4 repeated measurements of ALT, those with persistently abnormal ALT levels (n = 118) had a strong, significantly increased HCC rate compared to those with persistently normal ALT levels (n = 296) (HR = 23.2; 95% CI: 3.0, 178.5). This study demonstrates that elevated ALT levels, measured on an average of 8 years before HCC diagnosis, predict an increased rate of HCV-associated HCC in a community-based population and that utilizing serial measurements to identify persistent ALT abnormality may be useful in determining HCC risk.

Aged↗

PubMed2006

Interleukin-10 or tumor necrosis factor-alpha polymorphisms and the natural course of hepatitis C virus infection in a hyperendemic area of Japan.

We investigated the effects of polymorphisms in interleukin (IL)-10 and tumor necrosis factor (TNF)-alpha on the natural course of hepatitis C virus (HCV) infection in a community-based population in Japan. A total of 460 anti-HCV antibody seropositive individuals were classified into two groups, those who were positive or negative for HCV RNA. In HCV RNA-positive individuals with at least four annual alanine aminotransferase (ALT) measurements taken between 1993 and 2003, 74 exhibited persistently normal ALT levels, while 211 had one or more elevated ALT level tests. We examined the relationships between polymorphisms in the genes encoding IL-10 (-1082, -819, -592) or TNF-alpha (-308, -238) and HCV clearance, ALT abnormalities, or serum level of type IV collagen 7S, a marker of hepatic fibrosis. These polymorphisms were equally distributed among the patient subgroups with differential HCV RNA clearances or ALT abnormalities. Serum levels of type IV collagen 7S, however, were significantly higher in individuals with an A at position -238 or -308 in the TNF-alpha gene promoter than in individuals lacking these polymorphisms. We conclude that, while the relationships between inherited variations in IL-10 or TNF-alpha expression are not associated with alterations in HCV clearance or ALT levels, TNF-alpha polymorphisms may be associated with hepatic fibrosis.

Alanine Transaminase↗

PubMed2006

Patterns of serum type 1 and type 2 immune markers in healthy carriers of HTLV-I.

Type 1 immunity appears to be diminished in healthy Japanese carriers of human T-lymphotropic virus type I (HTLV-I), but type 2 status remains undetermined. To further examine the subclinical effect of HTLV-I on host immunity, we measured serum antibodies to the Epstein-Barr virus (EBV) in 415 healthy Japanese adults to broadly characterize type 1 status. Levels of the type 2 biomarkers total immunoglobulin E (IgE), soluble CD23 (sCD23), and soluble CD30 (sCD30) were assessed in 167, 142, and 135 of these subjects, respectively. We analyzed the association of HTLV-I with levels of each serum marker using linear and logistic regression. Altered EBV antibody profiles that are consistent with deficient type 1 immunity were more prevalent in HTLV-I carriers than non-carriers (odds ratio (OR) = 2.8, 95% confidence interval (CI) = 1.5-5.3). Carriers also had 45% lower total IgE levels (P = 0.04) than non-carriers. In contrast, HTLV-I infection was not significantly associated with elevated levels of sCD23 or sCD30. These observations are contrary to our expectation of elevated type 2 biomarkers among carriers. We conclude that in this population, healthy carriers of HTLV-I may have subclinical deficiencies in both type 1 and type 2 immunity, and that type 1 and type 2 immunity are not necessarily reciprocal in persons with subclinical immune dysregulation.

Adult↗

PubMed2006

Navigator-echo-based MR provides high-resolution images and precise volumetry of swine livers without breath holding or injection of contrast media.

The accurate calculation of hepatic volume by computed tomography (CT) or magnetic resonance (MR) is complicated by the need for breath holding and the injection of contrast media. These are often contraindicated in patients with liver failure, and we examined the ability of unenhanced 3-dimensional (3-D) navigator-echo-based MR (NE-MR) to accurately image livers and measure volumes without breath holding compared to unenhanced (plain) or gadolinium-diethylene triamine pentaacetic acid enhanced MR (Gd-MR) in miniature swine (n = 8). Without breath holding, diaphragm movement monitoring with NE-MR reduced motion artifacts in hepatic images compared with the other modalities. Without the injection of contrast media, the signal-to-noise ratios of the images obtained using NE-MR were significantly higher than those from plain MR; Gd-MR was superior to NE-MR, however (79.5 +/- 7.5 vs. 63.2 +/- 6.0 or 97.8 +/- 8.1, respectively; P < 0.01 for each). Overall, NE-MR produced improved high-resolution liver images. Consequently, liver volumes calculated based on NE-MR images were more highly correlated with actual liver weights compared to plain or Gd-MR in the whole livers (n = 8; r = 0.937 vs. 0.835 or 0.904, respectively). Also, NE-MR demonstrated significantly strong correlation between actual weights and volumetry-calculated volumes in regenerative livers 7 days after massive hepatectomy (n = 10, r = 0.989, P < 0.01). In conclusion, our results indicate that without breath holding or the injection of contrast media, 3-D NE-MR can provide both high-resolution liver images and precise hepatic volumes in patients with liver failure due to liver surgery (massive hepatectomy and living donor liver transplantation) or fulminant hepatic failure.

Animals↗

PubMed2006

Host immune status and incidence of hepatocellular carcinoma among subjects infected with hepatitis C virus: a nested case-control study in Japan.

A nested case-control study was conducted to examine the association between host immune status, as characterized by serum immune marker levels, and the development of hepatocellular carcinoma (HCC) up to 8 years later in persons with chronic hepatitis C virus (HCV) infection. Cases (n = 39) and matched controls (n = 117) were selected from participants of the Town C HCV Study in Japan between 1996 and 2004 and matched on age at first available sample (+/-1 year), gender, and length of follow-up. Separate analyses were done for each of three serum immune markers: soluble tumor necrosis factor-receptor II (sTNF-R2) and soluble intercellular adhesion molecule-1 (sICAM-1), as indicators of type 1, cell-mediated immune response, and soluble CD30 (sCD30), as an indicator of type 2, humoral immune response. The median concentrations of sTNF-R2, sICAM-1, and sCD30 among controls were 3,170 pg/mL, 305 ng/mL, and 3.0 units/mL, respectively, and were higher among cases (3,870 pg/mL, 372 ng/mL, and 3.3 units/mL, respectively). The risk of developing HCC among subjects with immune marker concentrations above the median levels of the controls was >2-fold greater than among subjects with lower concentrations for all three markers [sTNF-R2: odds ratio (OR), 6.9; 95% confidence interval (95% CI), 2.4-20.5; sICAM-1: OR, 2.0; 95% CI, 0.9-4.1; and sCD30: OR, 2.1; 95% CI, 1.0-4.7]. Simultaneous adjustment for all three markers revealed only sTNF-R2 to be associated with HCC risk (OR, 6.4; 95% CI, 2.0-20.6). Adjustment for alcohol consumption and HCV serotype did not materially alter these associations. Results from this prospective, community-based study suggest that a dysregulation in both type 1-related and type 2-related host immunity contributes to the development of HCV-associated HCC.

Aged↗

PubMed2006

Repeated intravenous injection of recombinant human hepatocyte growth factor ameliorates liver cirrhosis but causes albuminuria in rats.

Hepatocyte growth factor (HGF) is a promising agent for the treatment of liver cirrhosis because of its mitogenic and anti-fibrotic effects. We investigated the effect of recombinant human HGF (rh-HGF) on cirrhosis development; its pharmacokinetics and nephrotoxicity in rats with liver cirrhosis induced by 4-week treatment with dimethylnitrosamine (DMN). rh-HGF (0.3 mg/kg) was intravenously administered to rats once a day for 4 weeks in parallel with DMN treatment or twice a day for the last 2 weeks of DMN treatment. Repeated doses of rh-HGF increased the liver weight and serum albumin, and reduced serum ALT. The development of hepatic fibrosis was inhibited more efficiently by extended low-dose treatment with rh-HGF. In cirrhotic rats, serum levels of rh-HGF increased and clearance was decreased, leading to an increase in the area under the plasma-concentration time curve and a decrease in the steady-state volume of distribution. Repeated doses of rh-HGF led to increased urinary albumin excretion, but no rh-HGF-treated animals developed increased serum creatinine levels. Urinary albumin excretion returned to baseline after the cessation of rh-HGF. These results suggest that extended treatment with rh-HGF is required for the attenuation of cirrhosis, and repeated doses of rh-HGF cause adverse effects in extra-hepatic organs. These issues must be resolved before the widespread application of rh-HGF in the treatment of liver cirrhosis.

Alanine Transaminase↗

PubMed2006

Enhanced cell-substratum adhesion of E-cadherin-expressing cells is mediated by activation of the small GTPase protein, Rac1.

L cell transfectants stably expressing E-cadherin demonstrate a remarkable increase in adherence to extracellular matrix proteins, such as type IV collagen and fibronectin. This enhanced adhesion is mediated by integrin-type cell surface receptors, as assessed by inhibition with anti-receptor antibodies. Both the rate and efficiency of adhesion were enhanced 4- to 5-fold. In contrast, non-specific adhesion processes, such as cell attachment to polylysine-coated substrata, are unaffected by E-cadherin expression. Thus, integrin-mediated but not non-specific adhesion is modulated by E-cadherin expression. L cells expressing mutant E-cadherin molecules either lacking the cytoplasmic domain or bearing an amino acid substitution in the Ca2+-binding motif did not exhibit enhanced adhesion. The amount of collagen receptor, the alpha1 and beta1 integrin, did not change following expression of E-cadherin. Pull-down assays with the Cdc42/Rac interactive binding (CRIB) domain of the Rac effector, p21-activated kinase, revealed increased Rac-GTP levels in cells expressing wild-type E-cadherin. These results suggest that the activation of Rac is involved in the enhancement of integrin-mediated adhesion induced by E-cadherin expression.

Animals↗

PubMed2006

Effect of hepatocyte growth factor on endogenous hepatocarcinogenesis in rats fed a choline-deficient L-amino acid-defined diet.

Hepatocyte growth factor (HGF) is a promising agent for the treatment of intractable liver disease, due to its mitogenic, anti-apoptotic, and anti-fibrotic effects. We investigated the effect of recombinant human HGF (rh-HGF) on the development of both hepatocellular carcinoma (HCC) and preneoplastic nodules in rats fed a choline-deficient L-amino acid-defined (CDAA) diet, an animal model of hepatocarcinogenesis resembling human development of HCC with cirrhosis. From weeks 13 to 48 of the CDAA diet, rh-HGF (0.1 or 0.5 mg/kg/day) was administered intravenously to rats in four-week cycles, with treatment for five consecutive days of each week for two weeks, followed by a two-week washout period. Treatment with rh-HGF significantly inhibited the development of preneoplastic nodules in a dose-dependent manner at 24 weeks. Although the numbers and areas of the preneoplastic nodules in rats treated with rh-HGF were equivalent to those in mock-treated rats by 60 weeks, the incidence of HCC was reduced by HGF treatment. Although one rat treated with low-dose rh-HGF exhibited a massive HCC, which occupied almost the whole liver, and lung metastases, HGF treatment did not increase the overall frequency of HCC. Administration of high-dose rh-HGF, however, induced an increase in the urinary excretion of albumin, leading to decreased serum albumin at 60 weeks. These results indicate that long-term administration of rh-HGF does not accelerate hepatocarcinogenesis in rats fed a CDAA diet. However, these findings do not completely exclude the potential of HGF-induced hepatocarcinogenesis; this issue must be resolved before rh-HGF can be used for patients with intractable liver diseases, especially those with cirrhosis.

Albumins↗

PubMed2006

[A case of gastric endocrine cell carcinoma with liver metastasis showing rapid growth during pregnancy and marked reduction by systemic chemotherapy after delivery].

A 28-year-old woman was given a diagnosis of gastric endocrine cell carcinoma with multiple liver metastases in 1997. Chemotherapy was administered for treatment after a distal gastrectomy and hepatic tumor resection, and she had shown no sign of relapse after 2002. In February 2004, she was in the third month of pregnancy, and experienced recurrent liver metastasis. Although the tumor grew rapidly from 3cm to 10cm during her pregnancy, its size was significantly reduced with systemic chemotherapy after delivery. This is a rare case in which a liver metastasis of a gastric endocrine cell carcinoma grew during the course of pregnancy.

Adult↗

PubMed2005

Spontaneous elimination of hepatitis C virus RNA in individuals with persistent infection in a hyperendemic area of Japan.

The natural course of hepatitis C virus (HCV) carriers is not well understood. We examined the clinical characteristics of individuals exhibiting spontaneous elimination of HCV as part of a cohort study of residents of a HCV hyperendemic area in Japan. In individuals who were judged to have persistent HCV infection in 1995, 302 had at least 4 annual ALT measurements between 1993 and 2000, and had not been treated with IFN. They were tested for the presence of HCV RNA in 2001 and/or 2002 and HCV RNA could not be detected in 20 of the 302 individuals. In these 20 individuals, 7 were confirmed to have detectable HCV RNA and 13 were not until 2000. Thus, 2.4% (7/289) were judged to have spontaneously eliminated the HCV infection during that 6-year period. Although there were no differences in age, sex, ALT levels, or serologically defined HCV genotype between individuals with and without exhibiting spontaneous elimination, there was a significant relationship between the elimination of HCV RNA and a low level of HCVcAg (<20pg/mL) (P<0.001) upon testing in 1995. These results suggest that spontaneous elimination of HCV RNA following persistent infection is rare and appears to be related to viral load.

Journal Article↗

PubMed2005

Timing of interferon therapy and sources of infection in patients with acute hepatitis C.

BACKGROUND/AIMS: Controversy over the selection of patients and optimum therapeutic method for acute hepatitis C has continued. The aims of this study were to investigate the source of infection, and to evaluate the timing of interferon (IFN) therapy in patients with acute hepatitis C in Japan. METHODS: The records of 102 patients from 12 facilities in Japan who developed acute hepatitis C after 1990 were investigated. In the patients treated with IFN, we performed multivariate analysis to investigate factors related to sustained virological response (SVR). RESULTS: Medical procedure was the most common source of infection, accounting for 32.4% in the 102 patients (33/102). Of 81 patients treated with IFN, 71 patients were followed after IFN therapy, and 57/71 (80.3%) had SVR. The SVR rate was significantly higher in patients treated with IFN within 24 weeks from onset of symptoms than the SVR rate in those treated after 25 weeks (P=0.0016). Multivariate analysis revealed that only the duration between onset of symptoms and initiation of IFN therapy (within 24 weeks) was related to SVR. CONCLUSIONS: Our multicenter cooperative survey revealed that medical procedure was the most frequent source of infection in acute hepatitis C. As concerns the therapy, interferon treatment should be initiated within 24 weeks after onset of symptoms.

Journal Article↗

PubMed2005

Development of a rapid semi-quantitative immunochromatographic assay for serum hepatocyte growth factor and its usefulness in acute liver failure.

Measurement of serum human hepatocyte growth factor (HGF) by enzyme-linked immunosorbent assay (ELISA) is useful for the early diagnosis and prediction of prognosis of patients with acute liver failure (ALF). This ELISA methodology, however, is neither rapid nor convenient for use at the bedside. In this study, we have developed a rapid semi-quantitative immunochromatographic (IC) assay and evaluated its usefulness in assessing patients with acute hepatic injury. Only 100mul of serum is required; the assay can be easily completed in 20min. The values obtained using this novel assay correlated well with the values obtained using the standard ELISA protocol. In addition, the values obtained in the IC assay correlated with clinical course; increased serum HGF levels were associated with an increased frequency of ALF and death. These results indicate that this rapid semi-quantitative IC assay for HGF is useful for the early diagnosis of ALF and prediction of clinical outcome in acute hepatic injury.

Journal Article↗

PubMed2005

Apolipoprotein E regulates primary cultured human mesangial cell proliferation.

BACKGROUND: The role of apolipoprotein (apo) E in kidney disease is still unclear. Animal studies have been performed, but it is doubtful if the conclusions are applicable to human beings. The objective of this study was to determine how apo E acts on human kidneys using primary cultured normal human mesangial cells (NHMCs) rather than animals used in previous studies. METHODS: apo E and its isoforms E2, E3 and E4, or combinations with apo B were cocultured with primary NHMCs in serum-free medium. Premix WST-1 Cell Proliferation Assay System and DNA-Prep Reagent System were used to measure the proliferation and apoptosis of NHMCs, respectively. RESULTS: (1) apo E itself increased NHMC proliferation at 24 h of culture, while it inhibited this proliferation after 48 h. (2) At 72 h of culture, apo E alone inhibited NHMC proliferation at concentrations higher than 0.78 microg/ml in concentration-dependent manner. (3) When co-cultured with both apo E and apo B, NHMC proliferation was higher than that with apo E alone and lower than that with apo B alone. (4) At 72 h of culture, apo E2, E3 and E4 inhibited NHMC proliferation at different intensities, with no proliferative effect observed. (5) Neither apo E nor apo B caused NHMC apoptosis. CONCLUSION: apo E regulates primary NHMC proliferation by (1) inhibiting NHMC proliferation or reducing NHMC proliferation induced by apo B, which implies that apo E has a protective effect on the kidney, and (2) increasing the proliferation under certain conditions.

Apolipoprotein E2↗

PubMed2005

Hepatocyte growth factor delivered by ultrasound-mediated destruction of microbubbles induces proliferation of cardiomyocytes and amelioration of left ventricular contractile function in Doxorubicin-induced cardiomyopathy.

At present, there is no curative strategy for advanced cardiomyopathy except for cardiac transplantation, which is not easily performed, mainly due to a shortage of donors. It has been reported that myocardial progenitor cells exist even in the postnatal heart, suggesting that myocardial progenitor cells could proliferate under some situations and might improve cardiac function in cardiomyopathy-induced hearts. In this study, recombinant human hepatocyte growth factor (rhHGF) was delivered using ultrasound-mediated destruction of microbubbles (UMDM) into the cardiomyopathy-induced heart by doxorubicin (20 mg/kg). Intravenous injection of rhHGF (IV-rhHGF) alone or UMDM alone failed to improve the morphology or the function of the cardiomyopathy-induced heart, but (IV-rhHGF + UMDM) treatment significantly improved the heart morphologically and functionally, and repetitive treatments of (IV-rhHGF + UMDM) enhanced the effects. The number of bromodeoxy-uridine-positive cardiomyocytes significantly increased in the (IV-rhHGF + UMDM)-treated hearts compared with the untreated hearts. Moreover, Sca-1+ myocardial progenitor cells express c-Met, a receptor for HGF. These results suggest that (IV-rhHGF + UMDM) treatment could morphologically and functionally improve the heart in the case of doxorubicin-induced cardiomyopathy through the proliferation of the myocardial progenitor cells.

Animals↗

PubMed2005

The peroxisome proliferator-activated receptor-gamma agonist, pioglitazone, inhibits fat accumulation and fibrosis in the livers of rats fed a choline-deficient, l-amino acid-defined diet.

Administration of a choline-deficient, l-amino acid-defined (CDAA) diet to rats causes steatohepatitis, hepatic fibrosis, and hepatocellular carcinoma, a pathology similar to that observed in non-alcoholic steatohepatitis (NASH). The aim of this study was to evaluate if a peroxisome proliferator-activated receptor (PPAR)-gamma agonist, pioglitazone (PGZ), could ameliorate CDAA diet-induced fatty liver and cirrhosis. Rats were fed a CDAA diet for 1 week and were given the CDAA diet for an additional week with or without PGZ (2-week model). Also, after administration of the CDAA diet for 12 weeks, rats were administered the CDAA diet for an additional 4 weeks with or without PGZ (16-week model). The CDAA diet, administered for either one or 12 weeks, induced fatty liver or cirrhosis with up-regulation of hepatic PPAR-gamma expression, respectively. In the 2-week model, rats treated with PGZ for 1 week demonstrated significantly lower hepatic triglyceride content and serum levels of tumor necrosis factor-alpha. In the 16-week model, treatment for 4 weeks with PGZ ameliorated hepatic fibrosis with a decrease in the expression of procollagen, alpha-smooth muscle actin, and transforming growth factor-beta1 in comparison to rats without PGZ. These results suggest that PPAR-gamma agonist is a potential therapeutic modality to treat NASH.

Journal Article↗

PubMed2005

Modulation of hepatocyte growth factor induction in human skin fibroblasts by retinoic acid.

Topical treatment of skin with all-trans-retinoic acid (ATRA), the major biologically active form of vitamin A, results in hyperproliferation of basal keratinocytes, leading to an accelerated turnover of epidermis cells and thickening of the epidermis, probably via induction of production of paracrine growth factors for keratinocytes in epidermal suprabasal keratinocytes and/or dermal fibroblasts. Since hepatocyte growth factor (HGF) is a factor mitogenic to epidermal keratinocytes secreted from dermal fibroblasts, the effect of ATRA on basal and induced HGF production in human dermal fibroblasts in culture was examined. ATRA alone did not induce HGF production, but it significantly enhanced HGF production induced by the cAMP-elevating agent cholera toxin or the membrane-permeable cAMP analog 8-bromo-cAMP. Cholera toxin-induced activation of cAMP responsive element (CRE)-binding protein (CREB) was enhanced by pretreating cells with ATRA for 24 h. In contrast, HGF production induced by epidermal growth factor (EGF) or phorbol 12-myristate 13-acetate (PMA) was potently inhibited by ATRA. These modulatory effects of ATRA were different from the effects of transforming growth factor-beta1 (TGF-beta) and dexamethasone, both of which inhibited HGF production induced by all of the four inducers. Up-regulation of HGF gene expression by cholera toxin and EGF was also enhanced and inhibited, respectively, by ATRA. Both 9-cis-retinoic acid (9-cis-RA) and 13-cis-retinoic acid (13-cis-RA), which are stereo-isomers of ATRA, showed a modulatory effect on HGF induction similar to that of ATRA. These results suggest that ATRA augments the induction of HGF production caused by increased intracellular cAMP.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed2005

The clonal expansion of human T lymphotropic virus type 1-infected T cells: a comparison between seroconverters and long-term carriers.

BACKGROUND: The clonal expansion of human T lymphotropic virus type 1 (HTLV-1)-infected T cells is considered to be important for the maintenance of infection. However, the process by which the clonality of HTLV-1-infected T cells is established is not understood. METHODS: HTLV-1 clonality in 4 adult seroconverters was analyzed by inverse long polymerase chain reaction (PCR) followed by cloning of the PCR products and evaluation of restriction fragment-length polymorphism. The results were compared with those for 8 long-term HTLV-1 carriers. RESULTS: The clonality of HTLV-1-infected T cells in the seroconverters arose stochastically and was variable 3-5 years after seroconversion. On the basis of the frequency with which clones of cells infected with unique HTLV-1 provirus integration sites appeared, it was clear that the seroconverters had a greater number of unique clones with fewer infected cells than did the long-term carriers. CONCLUSIONS: The clonality of the HTLV-1-infected T cells in the adult seroconverters, who had been newly infected via HTLV-1-carrier spouses, was more heterogeneous and less stable than that of the HTLV-1-infected T cells in long-term carriers, who were more likely to have been infected during infancy. The mechanism for the selective maintenance of certain clones in asymptomatic HTLV-1 carriers likely plays a role in the initiation of leukemogenesis.

Aged↗

PubMed2005

Molecular mechanisms of hereditary persistence of alpha-fetoprotein (AFP) in two Japanese families A hepatocyte nuclear factor-1 site mutation leads to induction of the AFP gene expression in adult livers.

alpha-Fetoprotein (AFP) is produced abundantly in fetal liver but is hardly detectable in adults. In this study, we investigated two unrelated Japanese families with hereditary persistence of AFP. A g-->a substitution at nucleotide -119 (-119g-->a) in the hepatocyte nuclear factor (HNF)-1 binding site of the AFP promoter was identified in both families. The activity of the wild- or variant-type human AFP promoter was evaluated by in vitro and in vivo transfection experiments. This substitution in the AFP promoter significantly stimulated its transcriptional activity in human hepatoma cells, regardless of their prior AFP production. The variant-type AFP promoter was also active in adult mouse livers in vivo. Additionally, overexpression of HNF-1alpha stimulated the activity of both the wild- and variant-type AFP promoters in hepatoma cells. HNF-1alpha expression also activated both AFP promoters even in nonhepatoma cells, and this activation was suppressed by nuclear factor (NF)-I overexpression. These results indicate that an HNF-1 binding site mutation leads to induction of the AFP gene expression in adult liver, and suggest that competition between HNF-1 and NF-I in this region is involved in transcriptional regulation of the AFP gene during hepatic development.

Journal Article↗