Hideji Nakamura

Hepatoma-derived growth factor stimulates smooth muscle cell growth and is expressed in vascular development

Hepatoma-derived growth factor (HDGF) is the first member identified of a new family of secreted heparin-binding growth factors highly expressed in the fetal aorta. The biologic role of HDGF in vascular growth is unknown. Here, we demonstrate that HDGF mRNA is expressed in smooth muscle cells (SMCs), most prominently in proliferating SMCs, 8-24 hours after serum stimulation. Exogenous HDGF and endogenous overexpression of HDGF stimulated a significant increase in SMC number and DNA synthesis. Rat aortic SMCs transfected with a hemagglutinin-epitope-tagged rat HDGF cDNA contain HA-HDGF in their nuclei during S-phase. We also detected native HDGF in nuclei of cultured SMCs, of SMCs and endothelial cells from 19-day fetal (but not in the adult) rat aorta, of SMCs proximal to abdominal aortic constriction in adult rats, and of SMCs in the neointima formed after endothelial denudation of the rat common carotid artery. Moreover, HDGF colocalizes with the proliferating cell nuclear antigen (PCNA) in SMCs in human atherosclerotic carotid arteries, suggesting that HDGF helps regulate SMC growth during development and in response to vascular injury.

Hepatoma-derived Growth Factor Stimulates Cell Growth after Translocation to the Nucleus by Nuclear Localization Signals

Hepatoma-derived growth factor (HDGF) is the original member of the HDGF family of proteins, which contains a well-conserved N-terminal amino acid sequence (homologous to the amino terminus of HDGF; hath) and nuclear localization signals (NLSs) in gene-specific regions other than the hath region. In addition to a bipartite NLS in a gene-specific region, an NLS-like sequence is also found in the hath region. In cells expressing green fluorescence protein (GFP)-HDGF, green fluorescence was observed in the nucleus, whereas it was detected in the cytoplasm of cells expressing GFP-HDGF with both NLSs mutated or deleted. GFP-hath protein (GFP-HATH) was distributed mainly in the nucleus, although some was present in the cytoplasm, whereas GFP-HDGF with a deleted hath region (HDGFnonHATH) was found only in the nucleus. Exogenously supplied GFP-HDGF was internalized and translocated to the nucleus. GFP-HATH was internalized, whereas GFP-HDGFnonHATH was not. Overexpression of HDGF stimulated DNA synthesis and cellular proliferation, although HDGF with both NLSs deleted did not. Overexpression of HDGFnonHATH caused a significant stimulation of DNA synthesis, whereas that of hath protein did not. HDGF containing the NLS sequence of p53 instead of the bipartite NLS did not stimulate DNA synthesis, and truncated forms without the C- or N-terminal side of NLS2 did not. These findings suggest that the gene-specific region, at least the bipartite NLS sequence and the N- and C-terminal neighboring portions, is essential for the mitogenic activity of HDGF after nuclear translocation.

Partial purification and characterization of human hepatoma-derived growth factor

A human hepatoma cell line, HuH-7, which was established from a hepatoma tissue removed at surgical operation from an adult Japanese male, grows autonomously in a serum-free chemically defined medium. A human hepatoma-derived growth factor with potent growth-promoting activity, was partially purified from the conditioned medium of HuH-7 cells, using ion-exchange, heparin affinity chromatography and gel filtration. The partially purified growth factor (HuHGF) is acid- and heat-labile, and sensitive to reduction and trypsin digestion. HuHGF, which is of relatively high molecular weight (about 64 kDa) examined by gel filtration, stimulates not only the DNA synthesis of Swiss mouse 3T3 fibroblasts, but also the growth of HuH-7 cells in serum-free chemically defined medium, suggesting that it is produced by and acts on HuH-7 cells as an autocrine growth factor. This putative growth factor may play an important role in the autonomous growth of hepatoma and may lead to useful diagnostic or therapeutic approaches to human hepatoma.

Expression of Hepatoma-Derived Growth Factor Is Correlated with Lymph Node Metastasis and Prognosis of Gastric Carcinoma

Purpose: Hepatoma-derived growth factor (HDGF) is a unique nuclear/growth factor and might play an important role in the development and progression of carcinomas. In the present study, association of HDGF expression with recurrence and prognosis of gastric carcinoma was examined. Patients and Methods: HDGF expression in 317 patients with gastric carcinoma (233 males and 84 females) with ages ranging from 26 to 81 years (median, 60 years) was analyzed by immunohistochemistry. Samples with >90% of tumor cells to express positive immunoreactivity similar to or stronger than that in endothelial cells both for nucleus and cytoplasm were regarded as HDGF index level 2, and others as HDGF index level 1. Results: One hundred and eighty-two cases showed level 1 HDGF expression, whereas 135 cases showed level 2 HDGF expression. Patients with level 2 expression showed higher rates of proximal tumor location (P < 0.0001), large tumor size (P < 0.0001), infiltrative tumor growth (P < 0.0001), presence of vascular and lymphatic invasion (P < 0.0001 for both), presence of lymph node metastasis (P < 0.0001), deep tumor invasion (P < 0.0001), and poorer disease-free and overall survival (P < 0.0001 for both) compared to those with level 1 expression. Multivariate analysis revealed HDGF expression level as an independent prognosticator for disease-free and overall survival. Conclusion: HDGF expression level was shown to be a prognostic factor for gastric carcinoma.

Hepatoma-Derived Growth Factor Is a Novel Prognostic Factor for Patients with Pancreatic Cancer

Purpose: Hepatoma-derived growth factor (HDGF) is a nucleus-targeted growth factor playing an important role in the development and progression of cancers. This study investigated the correlation of HDGF expression and prognosis in patients with pancreatic ductal carcinoma. Patients and Methods: HDGF expression in pancreatic cancer cell lines was analyzed by Western blotting. HDGF expression was analyzed by immunohistochemistry for 50 patients with primary ductal carcinoma of the pancreas (33 male and 17 female) ranging in age from 48 to 80 years (median, 65 years) receiving surgical treatment. Cancer cells showing stronger staining than the noncancerous ducts were regarded as positive. Cases showing positive staining in <90% and >90% of tumor cells were regarded as HDGF labeling index (LI) levels 1 and 2, respectively. HDGF LI was determined separately for the nucleus and the cytoplasm. Results: Western blotting showed HDGF expression in pancreatic cancer cells similar to that of hepatic cell lines. Twenty-three (46%) and 27 (54%) cases and 22 (44%) and 28 (56%) cases showed HDGF LI levels 1 and 2 for the nucleus and the cytoplasm, respectively. Patients with nuclear HDGF LI level 1 showed a significantly better 5-year survival rate (37.0%) than those with level 2 (6.8%; P = 0.023). No significant difference was observed in the cytoplasmic HDGF LI classification. Multivariate analysis revealed nuclear HDGF LI to be an independent prognosticator. Conclusions: These findings suggest that HDGF could be a novel prognostic factor for pancreatic ductal carcinoma.

The family of hepatoma-derived growth factor proteins: characterization of a new member HRP-4 and classification of its subfamilies.

Hepatoma-derived growth factor (HDGF)-related proteins (HRPs) comprise a family of polypeptides named after HDGF, which was identified by its mitogenic activity towards fibroblasts. In the present study, we describe a hitherto unknown HRP, termed HRP-4. The cDNA of bovine HRP-4 (bHRP-4) predicts a polypeptide of 235 amino acids. Northern- and Western-blot analyses of various bovine tissues demonstrated that HRP-4 is only expressed in the testis. Recombinantly produced bHRP-4 and murine HDGF (mHDGF) histidine-tagged polypeptides display growth-factor activity for cultured primary human fibroblasts at an optimum concentration of 1 ng/ml in serum-free medium. The growth-factor activity declines with increasing concentrations to reach background levels at 1 microg/ml. The expression of the fusion proteins, bHRP-4-green fluorescent protein and mHDGF-green fluorescent protein, in HEK-293 cells demonstrates nuclear localization of the proteins. bHRP-4 and mHDGF bind to the glycosaminoglycans heparin and heparan sulphate, but not to chondroitin sulphate. Affinity constants determined for these interactions are between 6 and 42 nM. Comparison of the bHRP-4 amino acid sequence with HRP-1-3 and p52/75/lens epithelium-derived growth factor (LEDGF) shows that these proteins share a conserved N-terminal part of 91 amino acids but have C-termini of different lengths and charge. This demonstrates the modular structure of these proteins and allows its classification into three groups based on charge, size and sequence comparison. HRP-4, HRP-1 and HDGF are small acidic proteins, HRP-3 is a small basic protein, and HRP-2 and p52/75/LEDGF are larger basic proteins.

Hepatoma‐derived growth factor is highly expressed in developing liver and promotes fetal hepatocyte proliferation

Hepatoma‐derived growth factor (HDGF) is a heparin‐binding protein, which has been purified from the conditioned media of HuH‐7 hepatoma cells. Recent studies have suggested the involvement of HDGF in development of the kidney and cardiovascular systems. In the present study, we investigated the possibility that HDGF was also involved in liver development. Northern blot and immunostaining revealed unique expression patterns of HDGF in liver development. HDGF expression was strongly detected in the fetal liver of the midgestation stage and was markedly decreased near birth. Its expression was mainly detected in stromal cells, including immature hepatocytes. Expression in hepatocytes decreased with differentiation. Administration of recombinant HDGF enhanced the growth of primary cultured fetal hepatocytes significantly, although the effect was small. The effect of exogenous HDGF on the proliferation of neonatal hepatocytes was also small and significant only at one point, despite the lower expression of endogenous HDGF, suggesting that the differences exist between fetal and neonatal hepatocytes. However, adenoviral introduction of HDGF antisense cDNA into the fetal hepatocytes significantly suppressed their proliferation, and the inhibitory effect of HDGF antisense virus was reversed by exogenous HDGF. In conclusion, HDGF helps regulate the hepatocyte proliferation in liver development. (HEPATOLOGY2002;36:1519–1527).

Hepatoma-derived growth factor induces tumorigenesis in vivo through both direct angiogenic activity and induction of vascular endothelial growth factor

Hepatoma‐derived growth factor (HDGF) is highly expressed in tumor cells, and stimulates their proliferation. In the present study, we investigated the role of HDGF in tumorigenesis and elucidated the mechanism of action. Stable transfectants of NIH3T3 cells overexpressing HDGF did not show significant anchorage‐independent growth in soft agar assay. However, these stable transfectants overexpressing HDGF generated sarcomatous tumors in nude mice. These tumors were red‐colored macroscopically, and histologically showed a rich vascularity. Immunohistochemical analysis using CD31 antibody showed new vessel formation. Recombinant HDGF stimulated proliferation of human umbilical vein endothelial cells in a dose‐dependent manner, and stimulated tubule formation. Furthermore, vascular endothelial growth factor (VEGF) was detected immunohistochemically in the tumor tissues. Transient expression of HDGF induced both VEGF gene and protein expression as demonstrated by a reporter assay using VEGF gene promoter. The administration of anti‐VEGF neutralizing antibody significantly suppressed, but did not block, the tumor growth of HDGF‐overexpressing cells in nude mice. Thus, these findings suggested that HDGF‐induced tumor formation in vivo involves induction of VEGF as well as direct angiogenic activity.

Hepatoma-Derived Growth Factor Is a Novel Prognostic Factor for Hepatocellular Carcinoma

BackgroundHepatoma-derived growth factor (HDGF) is involved in hepatocarcinogenesis, as well as in liver development and regeneration. This study investigated the correlation of HDGF expression with differentiation and prognosis of hepatocellular carcinoma (HCC).MethodsHDGF expression in 100 patients with HCC (81 men and 19 women) with ages ranging from 34 to 81 years (median, 61 years) receiving surgical treatment was analyzed by immunohistochemistry. HDGF messenger RNA expression was evaluated in 10 cases by reverse transcription-polymerase chain reaction. The immunostaining pattern in HCCs was categorized as a positive HDGF index (showing positive staining in >90% of tumor cells in both nucleus and cytoplasm) or a negative HDGF index (all others).ResultsTwenty-seven cases (27%) showed a positive and 73 (73%) showed a negative HDGF index. HDGF messenger RNA expression was significantly higher in four cases with a positive HDGF index than in six with a negative index. Cases with well-differentiated histological characteristics showed a higher rate of positive HDGF index than those with a poorly differentiated subtype. Univariate and multivariate analysis revealed significantly poorer disease-free and overall survivals in patients with a positive HDGF index compared with patients with a negative index.ConclusionsThese findings suggest the potential utility of HDGF immunohistochemistry in determining the prognosis of HCC.

Expression Level of Hepatoma-Derived Growth Factor Correlates with Tumor Recurrence of Esophageal Carcinoma

Hepatoma-derived growth factor (HDGF) is thought to play an important role in the development and progression of carcinomas. In the present study, association of HDGF expression with recurrence and prognosis of esophageal carcinoma (EC) was examined. HDGF expression in 111 patients with EC (101 men and 10 women) with ages ranging from 38 to 82 (median, 61) years was analyzed by immunohistochemistry. Samples in which >90% of tumor cells exhibited nuclear and cytoplasmic HDGF immunoreactivity at levels greater than or equal to what is observed in the endothelial cells were regarded as HDGF expression level 1, and others as HDGF expression level 0. Thirty-seven of 111 patients showed level 1 HDGF expression. There was no correlation between HDGF expression and other clinicopathologic factors. Patients with level 1 expression showed poorer disease-free and overall survival (P < .05 for both) compared with those with level 0 expression. HDGF expression was an independent prognostic factor for patients with early (pT1–2) stage of the disease, but not for those with advanced (pT3–4) stage. HDGF expression level was shown to be a prognostic factor for EC.