Magnetic resonance imaging and expression of vascular endothelial growth factor in hepatocellular nodules in cirrhosis and hepatocellular carcinomas

We summarized and discussed our previous research results on correlation between magnetic resonance (MR) imaging findings and vascular endothelial growth factor (VEGF) expression in benign or borderline hepatocellular nodules in cirrhosis, hepatocellular carcinomas (HCCs), and in the surrounding liver. Magnetic resonance images were retrospectively correlated quantitatively and qualitatively with VEGF expression in hepatic nodules and in the surrounding liver. By immunohistochemistry, hepatic nodules with moderate to strong immunoreactivity for VEGF showed higher T1 signal intensity, and those with intense immunoreactivity for VEGF showed higher T2 signal intensity. By Western blotting, HCC-to-liver contrast-to-noise ratio correlated with VEGF indices (VEGFs) of hepatocellular carcinomas inversely on opposed-phase T1-weighted, directly on T2-weighted, and marginally and inversely on gadolinium-enhanced hepatic arterial-phase images. On T2-weighted images, standard-deviation ratio of hepatocellular carcinomas correlated directly with VEGFs of hepatocellular carcinomas. Heterogeneities of hepatocellular carcinomas on MR images correlated directly with VEGFs of HCCs on opposed-phase T1-weighted, T2-weighted, hepatic arterial-phase, and equilibrium-phase images. Our results may reflect that MR signal intensity, hepatic arterial vascularity, and heterogeneity of hepatocellular nodules on MR images are closely related to the intensity of VEGF expression as up-regulated by hyper- or hypoxia in the nodules. Gadolinium-enhanced MR imaging may be useful to monitor ischemic state of hepatocelluar nodules. Although real impacts of our results on radiologic practice have been still debatable, we believe that our results may help future radiologic practice in conjunction with biomolecular or genetic treatments for hepatocellular carcinomas.

Inflammatory pseudotumor of the liver: ferumoxide-enhanced MR imaging as a tiebreaker

We examined a 70-year-old male patient with an inflammatory pseudotumor of the liver mimicking a peripheral-type cholangiocellular carcinoma. Ferumoxide-enhanced magnetic resonance (MR) imaging revealed residual Kupffer cell function in liver parenchyma in and surrounding the inflammatory pseudotumor involvement, which suggested the diagnosis of inflammatory pseudotumor of the liver. We correlate the MR imaging and pathologic findings in this report.

The clinical significance of monitoring alkaline phosphatase level to estimate postoperative liver failure after hepatectomy

BACKGROUND/AIMS

To predict the occurrence of postoperative liver failure after hepatectomy, the clinical significance of monitoring alkaline phosphatase (ALP) has been studied, and the relationship between the change of total bilirubin and the level of ALP or gamma-glutamyl transpeptidase (gamma-GTP) after hepatectomy was evaluated.

METHODOLOGY

The 163 patients, who underwent hepatectomy at our institute for the past 12 years, were divided into three groups according to the postoperative events. HF consisted of 5 patients with liver failure, HB showed the postoperative high bilirubinemia (over 5mg/dL) in 13 cases and GP were 145 cases without any postoperative problems.

RESULTS

1. The postoperative highest level of total bilirubin (T-Bil) correlated with the decreasing rate of ALP, prothrombin time (PT), total cholesterol (T-CHO) or gamma-GTP and total blood loss (p<0.01). 2. The level of ALP decreased after hepatectomy significantly and the decreasing rate was serious in HB and HF (p<0.05). 3. The recovering time to preoperative level of ALP was clearly shorter in GP than in HB and HF. 4. The level of ALP and gamma-GTP at the point where the level of T-Bil increased over 5mg/dL, was useful to distinguish between HF and HB. 5. The good correlation between postoperative level of ALP and gamma-GTP was noted. The decreasing levels of ALP and gamma-GTP were found to be critical below 80% and 55% after bisegmentectomy. Furthermore, the recovered levels of ALP and gamma-GTP were important to distinguish between HF and HB.

CONCLUSIONS

Monitoring the ALP level was indicated to be useful to estimate the postoperative course of bilirubin.

Large solitary fibrous tumor of the retroperitoneum: report of a case

We report an unusual case of a large solitary fibrous tumor (SFT) in the retroperitoneum. A 53-year-old man was referred to our hospital for surgical treatment of a swelling in the right flank with dull pain. Abdominal computed tomography (CT) and echograms showed a large encapsulated tumor compressing the right kidney and liver. At laparotomy, the tumor was found to be encapsulated but fixed to the capsule of the right kidney within a small area. Therefore, complete removal was achieved. The resected specimen was an encapsulated elastic hard tumor, 14 x 13 x 10 cm in size. Immunohistochemical studies revealed reactivity for CD34 and vimentin, but no staining for keratin, S-100, or alpha-smooth muscle actin, confirming a diagnosis of SFT. Although SFT is usually associated with a favorable prognosis, close follow-up is recommended because of the limited information on its long-term behavior.

A case report of papilla Vater carcinoma showing positive expression of thymidine phosphorylase

Recently, we experienced an interesting case of papilla Vater carcinoma. The patient was a 61-year-old woman, who was referred to our department from a private hospital with a chief complaint of high fever. Magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography revealed an anomalous arrangement of the pancreaticobiliary duct without a common channel and a tumor, which was detected on the papilla Vater and diagnosed as well-differentiated adenocarcinoma. Pylorus-preserving pancreaticoduodenectomy with lymph node dissection was performed. The immunohistochemical stain showed the strong expression of thymidine phosphorylase in the tumor tissue and also in the normal biliary tract, despite positive p53 cells being undetected in either tumor tissue or epithelium of biliary tract. These findings may suggest important indications to consider some mechanisms of carcinogenesis in the biliary tract.

[Percutaneous cryoablation therapy under local anesthesia for unresectable metastatic liver tumors]

Even though liver resection is the first choice against metastatic liver tumors, oncologists are often obliged to include other treatment modalities depending on metastatic tumor size, number of metastatic nodules, location of tumors, patient's general condition, and so on. Among others we selected cryoablation therapy against unresectable tumors and examined its usefulness clinically in 5 patients. Under local anesthesia, the cryoprobe, which was 3 mm in diameter, was introduced into the center of the tumor by use of an ultrasonographic guiding technique. In the middle of the freezing process, through ultrasonography we could clearly monitor the target tumor, which would change into an ice ball. It was noteworthy that not only the treated tumor but also untreated tumors were reduced in 2 cases. Because of extra-hepatic metastases, 3 patients died within 1 year after the therapy, while 2 patients are alive. This modality was easily repeatable and was minimally invasive with little toxic effect. In addition, it did not worsen quality of life (QOL). The above results indicate that cryoablation therapy could be a feasible modality against unresectable metastatic liver tumors.

New approach to cancer therapy: the application of signal transduction to anti-cancer drug

Although it has been widely known that extracellular signal-regulated kinase (ERK) pathway stimulates cell growth and have a protective effect from cell death, recent findings propose pro-apoptotic action of ERK phosphorylation. Since it was found that Vitamin K3 (VK3) or its analog was a potent growth inhibitor and inducer for ERK phosphorylation through specific pathway in cancer cell line, the critical role of ERK phosphorylation in growth inhibitory actions can be discussed. VK3 induced receptor tyrosine phosphorylation and occurred at growth inhibitory concentrations. The phosphorylation of growth factor receptor by VK3 was indicated to be functional, since these were connected with growth factor receptor-bound protein 2 (Grb2) and SOS1. The growth factor stimulated to induce cyclin D1 protein and increase DNA contents. In addition, ERK inhibitor antagonized increase of cyclin D1, suggesting that ERK phosphorylation by growth factor might play an essential role for cell growth. By contrast, ERK phosphorylation by VK3 was more prolonged and intense than the signal induced by growth factors and the antagonize ERK phosphorylation protected from growth inhibition by VK3. The additional and extra ERK spot by VK3, compared with those obtained from growth factor, was detected on two dimensional gels, and this was completely and selectively antagonized by ERK inhibitor. Therefore, the overexpressed ERK phosphorylation was suggested to originate from the additional spot, which played a critical role in growth inhibitory action, despite ERK phosphorylation by growth factor had an essential association with cell growth. The new approach to consider the signal transduction can be one of the most favorite strategies for cancer therapy in the future.

Clinical significance of combination study of apoptotic factors and proliferating cell nuclear antigen in estimating the prognosis of hepatocellular carcinoma

BACKGROUND AND OBJECTIVES

Hepatocellular carcinoma (HCC) is one of the most common recurrence diseases, which affects the patient's prognosis. The aim of this report is to evaluate recurrence risk after primary treatment by the combination study with the clinical features and immunohistological findings.

METHODS

153 removable HCCs were examined by immunohistochemical study of the proliferating cell nuclear antigen (PCNA), p53, or Bax. The relationships of these factors with histological grades, the presence of intra-hepatic metastasis (IM), tumor size, value of serum alpha-fetoprotein (AFP), and prognosis were studied. PCNA labeling index (LI) was calculated to count positive nuclei in 1,000 cells.

RESULTS

PCNALI was significantly higher in cancer and correlated with tumor size. PCNALI and the tumor diameter in themselves could be a good predictor for patient prognosis and the combination study of them was an even stronger indicator. The value of AFP was significantly higher in positive p53 cases. The incidence of p53 was associated with histological types. The presence of IM was found in negative Bax cases of main tumors. The appearance of Bax was not correlated with histological types. The incidence of p53 or Bax was indicated to distinguish the patient prognosis of the lower grade histological cases, in which differences could not be found by the routine histological study.

CONCLUSIONS

The combination study of the immunohistochemical findings and the clinical features could be one of the most important aids in interpreting the status of HCC.

Small scirrhous hepatocellular carcinoma with central scar: MR imaging findings

We describe the magnetic resonance (MR) imaging findings of a small scirrhous hepatocellular carcinoma in a 74-year-old man. The initial MR imaging findings indicated that the tumor had a small central scar, which suggested the differential diagnoses of hepatocellular carcinoma, intrahepatic cholangiocarcinoma, and metastasis. A small scirrhous hepatocellular carcinoma may have a central scar and should be included in the differential diagnoses for small hepatic masses with a central scar.

Evaluation of treatment for synchronous hepatic metastases from gastric cancer with special reference to long-term survivors

PURPOSE

The purpose of this study was to determine the most effective means of treating liver metastases from gastric cancer.

METHODS

We retrospectively examined 43 patients with liver metastases, but without peritoneal dissemination, who had received different forms of treatment.

RESULTS

The crude 5-year survival rates of patients who underwent gastrectomy with complete hepatectomy (curative gastrectomy), noncurative gastrectomy, and no gastrectomy were 33.3%, 3.7%, and 0%, respectively. The curative gastrectomy group showed the highest survival rate (not significant). The median survival of patients given hepatic artery infusion (HAI), systemic chemotherapy, and no chemotherapy were 353, 189, and 61 days, respectively. The patients given chemotherapy survived significantly longer than those not given chemotherapy. Three patients survived for more than 5 years without any signs of recurrence. The long-term survivors all had primary lesions without serosal invasion (T2) and no other noncurative factors. Two patients underwent curative gastrectomy and one underwent noncurative gastrectomy. All were given postoperative chemotherapy; as HAI in two cases, and as systemic chemotherapy in one case.

CONCLUSION

These findings suggest that curative gastrectomy combined with HAI or systemic chemotherapy should be attempted for patients with primary tumors without serosal invasion or any other noncurative factors.

Comparative effects of plasmapheresis and intravenous cyclophosphamide on urinary podocyte excretion in patients with proliferative Lupus nephritis

Intravenous cyclophosphamide (IVC) in combination with steroids is standard therapy for Lupus nephritis. Reduction of autoantibodies and circulating immune complexes can be used in the treatment of autoimmune diseases. The aim of the present study was to compare the effects of IVC pulse therapy and double-filtration plasmapheresis (DFPP) on proteinuria and urinary excretion of podocytes in adult patients with diffuse proliferative Lupus nephritis (DPLN). Twenty patients were randomly assigned to two groups. Group A (n = 10) was treated with IVC (0.75 - 1.0 g/m2 body surface area) pulse therapy, given as boluses once a month for 6 consecutive months, combined with oral corticosteroid (up to 1 mg/kg/day) administration. Group B (n = 10) was treated with a combination of DFPP (performed 1-2 times weekly) and corticosteroid (up to I mg/kg/ day). The total average number of treatments was 8.4 and the therapeutic efficacies were evaluated after 6 months. Twenty healthy individuals participated as a control group. Urinary podocytes were examined by immunofluorescence with monoclonal antibodies against podocalyxin. Both Group A and Group B reduced proteinuria (p < 0.001) as well as the number of urinary podocytes (p < 0.001). Differences between the 2 treatment outcomes were not statistically significant. Cyclophosphamide pulse therapy and DFPP may be similarly effective in the treatment of podocyte injury in patients with DPLN.

Tumor cell growth inhibition and extracellular signal-regulated kinase (ERK) phosphorylation by novel K vitamins

2-(2-hydroxy-ethylsulfanyl)-3-methyl-1,4-naphthoquinone or CPD-5, a K vitamin analog, was previously indicated to be a potent growth inhibitor for Hep 3B hepatoma cells in vitro. Here, we show that CPD-5 and two newly synthesized analogs, 2-(2-hydroxy-ethylsulfanyl)-3-methyl-5- nitro-1,4-naphthoquinone (PD-37) and 2-(2-hydroxy-ethylsulfanyl)-3- methyl-5-acetylamino-1,4-naphthoquinone (PD-42), are potent growth inhibitors of 13 different human cancer cell lines, with IC50 values in the range of 3-54 microM. Phospho-ERK was induced by each of three K vitamin analogs in every cell line in a dose-dependent manner, at growth inhibitory doses. ERK phosphorylation and growth inhibitory effects were strongly correlated, with p=0.0080 for CPD-5, p=0.0076 for PD-37 and p=0.0251 for PD-42. The induction of phospho-ERK and growth inhibition were antagonized by thiol-containing anti-oxidants, but not by catalase, consistent with a possible arylating mechanism. The data show a novel class of growth inhibitors with a wide spectrum of action that induces ERK hyper-phosphorylation, as a possible new growth inhibitory feature.

Intrahepatic cholangiocarcinoma arising 10 years after the excision of congenital extrahepatic biliary dilation

A 52-year-old woman was found to have a liver tumor during treatment for a liver abscess. The tumor was diagnosed as intrahepatic cholangiocarcinoma by closer examinations, including a percutaneous needle biopsy. Ten years previously, she had undergone excision of a choledochal cyst, with reconstruction by Roux-en-Y hepaticojejunostomy, as treatment for Todani's type Ia congenital biliary dilation, which had been confined only to the extrahepatic bile duct. The significant association between congenital biliary dilation and hepatobiliary malignancies is well known. Some patients have been reported to develop biliary cancer long after the excision of the entire extrahepatic bile duct and hepaticoenterostomy. However, in these patients, the development mostly took place in the remnant choledochal cyst, the anastomotic site, or in the dilated intrahepatic bile duct of Todani's type IV-A congenital biliary dilation. The development of intrahepatic cholangiocarcinoma after operation has not been reported previously in a patient with Todani's type I congenital biliary dilation. This case suggests that the entire biliary tree may have a high risk of field cancerization, even in extrahepatic congenital biliary dilation.

The yeast SAS (something about silencing) protein complex contains a MYST-type putative acetyltransferase and functions with chromatin assembly factor ASF1

It is well established that acetylation of histone and nonhistone proteins is intimately linked to transcriptional activation. However, loss of acetyltransferase activity has also been shown to cause silencing defects, implicating acetylation in gene silencing. The something about silencing (Sas) 2 protein of Saccharomyces cerevisiae, a member of the MYST (MOZ, Ybf2/Sas3, Sas2, and TIP60) acetyltransferase family, promotes silencing at HML and telomeres. Here we identify a ~450-kD SAS complex containing Sas2p, Sas4p, and the tf2f-related Sas5 protein. Mutations in the conserved acetyl-CoA binding motif of Sas2p are shown to disrupt the ability of Sas2p to mediate the silencing at HML and telomeres, providing evidence for an important role for the acetyltransferase activity of the SAS complex in silencing. Furthermore, the SAS complex is found to interact with chromatin assembly factor Asf1p, and asf1 mutants show silencing defects similar to mutants in the SAS complex. Thus, ASF1-dependent chromatin assembly may mediate the role of the SAS complex in silencing.

Effect of cerivastatin on urinary albumin excretion and plasma endothelin-1 concentrations in type 2 diabetes patients with microalbuminuria and dyslipidemia

BACKGROUND/AIMS

To determine whether cerivastatin, a newly developed novel synthetic potent statin, exerts a renoprotective effect, we assessed urinary albumin excretion (UAE) and plasma and urinary endothelin (ET)-1 concentrations in normotensive microalbuminuric type 2 diabetes patients with dyslipidemia.

METHODS

Sixty normotensive type 2 diabetic patients (38 men and 22 women; mean age 56.5 years) with microalbuminuria (20-200 microg/min) and dyslipidemia (total cholesterol >200 mg/dl, LDL cholesterol >160 mg/dl, HDL cholesterol <35 mg/dl, and triglyceride >150 mg/dl) were enrolled in a double-blind study for 6 months, receiving either cerivastatin (0.15 mg/day) or placebo. Plasma and urinary ET-1 concentrations were measured by radioimmunoassay.

RESULTS

Cerivastatin did not affect serum creatinine and HbA(1c) levels, and reduced systolic blood pressure slightly, but not significantly. Plasma levels of total cholesterol and LDL cholesterol were significantly reduced (p < 0.01), and plasma triglyceride levels were also reduced significantly (p < 0.05) after 6 months of cerivastatin treatment. A concomitant significant decrease in UAE (p < 0.01), and urinary and plasma ET-1 concentrations (p < 0.01) were found during this period.

CONCLUSION

The use of cerivastatin is associated with decreased microalbuminuria and plasma and urinary ET-1 levels in microalbuminuric patients with type 2 diabetic mellitus and speculate that this may represent an amelioration of renal injury.

Pioglitazone reduces urinary podocyte excretion in type 2 diabetes patients with microalbuminuria

In various renal diseases, including diabetic nephropathy, detection of podocytes in the urine indicates severe injury to podocytes in the glomeruli. Pioglitazone is a newly developed antidiabetic agent that attenuates insulin resistance. The aim of the present study was to determine whether pioglitazone affects urinary albumin excretion (UAE) or the number of urinary podocytes or both in type 2 diabetes patients with microalbuminuria. Twenty-eight patients with normotensive type 2 diabetes and microalbuminuria (18 men and 10 women; mean age, 52.5 years) and 30 age-matched normotensive controls (20 men and 10 women; mean age, 51.5 years) were included in the study. Urinary podocytes were detected by immunofluorescence with a monoclonal antibody against podocalyxin. Patients were randomly assigned to 2 groups: a pioglitazone-treatment group (30 mg/day, n = 14) and a placebo group (n = 14). Treatment was continued for 6 months. Podocytes were absent in the urine of healthy controls, but detected in 17 of 28 diabetic patients (60.7%). UAE was reduced from 96.7 +/- 50.5 microg/min to 39.7 +/- 22.9 microg/min (P <.01) in the pioglitazone-treatment group, and the number of urinary podocytes was reduced from 0.9 +/- 1.0 cells/mL to 0.1 +/- 0.2 cells/mL (P <.001). Neither UAE nor the number of urinary podocytes was affected in the placebo group. These data indicate that pioglitazone is effective for reducing UAE and podocyte injury in early-stage diabetic nephropathy.

Mechanism of novel vitamin K analog induced growth inhibition in human hepatoma cell line

BACKGROUND/AIMS

To understand the mechanisms of liver regeneration or hepatoma apoptosis, it is important to estimate the turning point of the signal transduction by growth factor receptor. Since 2-(2-hydroxyethylsulfaryl) 3-methyl-1,4-naphthoquinone or CPD 5 has been shown to mediate the phosphorylation of epidermal growth factor (EGF) receptor in Hep3B hepatoma cells, the differences between EGF and CPD 5-mediated signal transduction were studied.

METHODS

DNA content was measured by Hoechst fluorescent assay. Phosphorylated proteins were described with Western blots or two-dimensional electrophoresis.

RESULTS

CPD 5-induced EGFR phosphorylation was functional to stimulate Ras pathway. However, CPD 5-mediated extracellular signal-regulated kinase (ERK) phosphorylation was not antagonized by inhibition of upstream activation with PD153035. CPD 5 inhibited ERK dephosphorylation in cell lysate, suggesting that ERK phosphorylation by CPD 5 was depending on kinase activity and phosphatase inhibition. Two-dimensional electrophoresis showed extra phospho ERK spot, which was indicated to have close association with CPD 5-induced growth inhibition, since U0126 antagonized growth inhibition and appearance of this spot.

CONCLUSIONS

The turning point of EGFR pathway was proved to have close association with the expressed level of phosphorylated ERK. ERK phosphorylation was suggested to play a critical role in growth factor-induced signal transduction.

Critical role of extracellular signal-regulated kinase phosphorylation on menadione (vitamin K3) induced growth inhibition

BACKGROUND

Although it is widely known that the extracellular signal-regulated kinase (ERK) pathway stimulates cell growth and protects cells from death, recent findings have proposed a proapoptotic action of ERK phosphorylation. Because the authors found that vitamin K3 (VK3) was a potent growth inhibitor and an inducer for ERK phosphorylation through a specific pathway in the stomach cancer cell line, the critical role of ERK phosphorylation in VK(3)-mediated growth inhibitory effect was examined.

METHODS

The fluorochrome Hoechst 33258 assay (Hoechst AG [now Aventis] Frankfort, Germany) was used for counting cells (excitation at 360 nm; emission at 460 nm). For two-dimensional electrophoresis, cells were dissolved in urea standard buffer and applied first to isoelectronic focusing gels. Cell lysates were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) using 10% polyacrylamide gels. To examine the phosphorylation of receptors, cell lysates were immunoprecipitated with receptor antibody.

RESULTS

VK3 induced phosphorylation of hepatocyte growth factor receptor (c-met), epidermal growth factor receptor (EGFR), or external signal-regulated kinase (ERK), which increased progressively to a maximum level at 30 minutes, in a dose-dependent manner and occurred at growth inhibitory concentrations. VK(3)-mediated growth inhibition and protein tyrosine phosphorylation were nullified completely by glutathione or L-cysteine but not by nonthiol antioxidants, thus suggesting that sulfhydryl arylation might have been involved in VK(3)-mediated action. The phosphorylation of EGFR and c-met by VK(3) appeared to be functional, because these were coimmunoprecipitated with growth factor receptor-bound protein 2 (Grb2) and SOS1 antibody. Epidermal growth factor (EGF) or hepatocyte growth factor (HGF) stimulated increase of cyclin D1 protein after 12 hours and increased DNA content after 3 days in culture. In addition, U0126, which is a potent inhibitor for ERK phosphorylation, antagonized increase of cyclin D1, thus suggesting that EGF- or HGF-mediated ERK phosphorylation might have played an essential role for cell growth. By contrast, ERK phosphorylation by VK3 was more prolonged and intense than the signal induced by the growth factors. U0126 reduced ERK phosphorylation and prevented growth inhibition by VK3. Two-dimensional gels showed VK(3)-induced additional phospho-ERK spots, compared with those obtained from growth factors. This extra spot was completely antagonized by U0126.

CONCLUSIONS

VK(3)-induced growth inhibition and protein tyrosine phosphorylation were mediated by the sulfhydryl arylation system. The tyrosine phosphorylation of EGFR or c-met by VK3 activated the Ras signaling pathway. The overexpressed ERK phosphorylation by VK3 seemed to originate from additional spots on two-dimensional gels, which played a critical role in VK(3)-induced growth inhibitory action despite the fact that ERK phosphorylation by growth factors had had an essential association with cell growth.

Identification of zinc finger proteins bound to a silencer region in the rat glutathione transferase P gene

The rat glutathione transferase P (GST-P) gene is strongly induced during chemical hepatocarcinogenesis, whereas mRNA of this gene is rarely expressed in normal rat liver. We previously identified a silencer region in the promoter of this gene. This silencer has several DNA binding sites and at least three proteins (Silencer factor A, -B, and -C (SF-A, SF-B, and SF-C)) bind to these sites. We previously cloned and characterized the Nuclear Factor 1 (NF1) family and the CCAAT/enhancer-binding protein (C/EBP) family as SF-A and SF-B, respectively. However, SF-C which binds to GST-P silencer 2 (GPS2) remains to be cloned. By screening using yeast one-hybrid system, several zinc finger proteins were identified as a candidate of SF-C. The gel-mobility shift analyses showed that BTEB2, EZF, LKLF, TFIIIA, TIEG1, and novel zinc finger protein MZFP bound to GPS2 with different affinities. Several proteins of these are known to be transcriptional activators or repressors, suggesting that zinc finger proteins bind to GPS2 and regulate GST-P expression in the rat liver.

Gene expression of CCAAT/enhancer-binding protein delta mediated by autoregulation is repressed by related gene family proteins

CCAAT/enhancer-binding protein delta (C/EBPdelta) transcription factor is rapidly induced at an early stage of acute phase response. We previously reported that this induction was mainly mediated by acute phase response factor/signal transducers and activators of transcription 3 (APRF/STAT3). Furthermore, the high expression level of C/EBPdelta is maintained by autoregulation mechanisms through the C/EBPdelta binding sites located downstream of C/EBPdelta gene. Thereafter, the expression of C/EBPdelta gene decreases rapidly to the basal level. However, these mechanisms are still unknown. According to both transfection and DNA binding analyses, liver-enriched inhibitory protein (LIP), the shorter form of C/EBPbeta and C/EBP-homologous protein 10 (CHOP10), were found to inhibit C/EBPdelta gene expression. DNA binding analysis has further indicated that both LIP and CHOP10 form heterodimers with C/EBPdelta, and inhibit the binding of C/EBPdelta homodimer to the C/EBPdelta binding sites located downstream of C/EBPdelta gene. Taken together, these findings indicated that the maintained expression of C/EBPdelta gene by autoregulation was inhibited and decreased to the basal level as a result of the competition of other C/EBP family proteins. Thus, C/EBPdelta gene expression is mediated by the gene regulation circuit through the downstream C/EBPdelta binding sites.

Critical role of extracellular signal-regulated kinase (ERK) phosphorylation in novel vitamin K analog-induced cell death

In the present study, we show that 2-(2-hydroxyethylsulfaryl)-3-methyl-1,4-naphthoquinone, or CPD 5, is a potent growth inhibitor for pancreas cancer cell lines (ID(50): 21.4 +/- 3.8, 31.8 +/- 2.7 and 55.2 +/- 4.5 microM for MiaPaCa, Panc-1 and BxPc3, respectively). It induced protein tyrosine phosphor-ylation of hepatocyte growth factor (HGF) receptor (c-Met) or epidermal growth factor receptor (EGFR), which increased progressively to a maximum level at 30 min in Panc-1 cells. The receptor phosphorylation by CPD 5 was indicated to be functional, since these receptors were found to bind with Grb2 or SOS1 protein. CPD 5 was also suggested to induce phosphorylation of external signal-regulated kinase (ERK). EGF induced cell proliferation through ERK phosphorylation, since U0126, which is an inhibitor of ERK phosphorylation, abrogated the increase of cyclin D1 by EGF. HGF increased the amount of p27 protein, suggesting that it is associated with cell differentiation. By contrast, U0126 reduced CPD 5-induced cell death. On two-dimensional electrophoresis, we found an extra type of phospho-ERK, and this was completely and selectively abolished by U0126. These results suggest that ERK phosphorylation, especially the extra spot on two-dimensional gel, is critically associated with CPD 5-mediated cell death.

Two nuclear localization signals are required for nuclear translocation of nuclear factor 1-A

Nuclear factor 1 (NF1) proteins are encoded by at least four genes (NF1-A, B, C, X). Although DNA-binding and the transcription regulation domains of these proteins are well characterized, the nuclear localization signals (NLSs) are still unknown in all NF1s. We have identified two NLSs in NF1-A, and both are required for full translocation to the nucleus, although one of them itself has a partial translocation ability. These two NLSs are conserved in all four NF1s. Interestingly, three isoforms of NF1-A (NF1-A1, A2, A4) have two NLSs and translocate completely to the nucleus. In contrast, NF1-A3 lacks the second NLS and partially stays in the cytoplasm. Since NF1s construct homodimer and heterodimer, these findings indicate the differential regulations of the NF1 translocation.

Macrophage-derived MT1-MMP and increased MMP-2 activity are associated with glomerular damage in crescentic glomerulonephritis

Membrane-type matrix metalloproteinases (MT-MMPs) have been shown to activate pro-MMP-2 on the cell surface and are suggested to be key enzymes in tissue remodelling under various physiological and pathological conditions. To investigate the role of MT-MMP in progressive renal injury, the gene expression and enzymatic activity of MT-MMP were examined in crescentic glomerulonephritis induced by anti-glomerular basement membrane (GBM) antibody in WKY rats. Isolated glomeruli were subjected to RNA and protein extraction 0, 1, 3, 7, 14, and 28 days after intravenous injection of rabbit anti-GBM antibody. Semiquantitative RT-PCR analysis revealed that among the three members of the MT-MMP family, mRNA expression of MT2-MMP remained unchanged and that of MT3-MMP was not observed in glomeruli during the development of nephritis. However, MT1-MMP gene expression increased from day 3 and reached maximum levels at day 7 (5.5+/-0.7-fold increase over day 0), closely associated with macrophage accumulation, crescent formation, and increased proteinuria. Gelatin zymography showed that the active from of MMP-2 emerged from day 7 and remained during the experimental period accompanied by increased proMMP-2, while no active form of MMP-2 was found in control rats. Using an antisense cRNA probe, intense signals of MT1-MMP mRNA were observed mostly in cells within the crescent and in some cells in the mesangial areas. Most of these cells were ED-1-positive macrophages, based on immunostaining of sequential sections. These results suggested that in the MT-MMP family, MT1-MMP was induced in infiltrating macrophages during the development of crescentic glomerulonephritis and possibly contributed to pathological degradation of glomerular extracellular matrices through the activation of proMMP-2.