Expression level of hepatoma-derived growth factor correlates with tumor recurrence of esophageal carcinoma

Heparin-binding growth factor (HDGF) drives radioresistance in breast cancer by activating the STAT3 signaling pathway

Although reports implicate radioresistance as an important obstacle for the management of breast cancer, its molecular mechanism is elusive. Herein, we found that high HDGF levels are expressed significantly in breast cancer and exhibit a positive association with poor survival prognosis. Heparin-binding growth factor (HDGF) was upregulated in radioresistant breast cancer cells, however, its knockdown could reduce breast cancer radioresistant both in vitro and in vivo. Additionally, the binding of RXRα to HDGF promoter blocked HDGF transcriptional activity, consequently inhibiting breast cancer radioresistance. The enhanced radioresistant activity of HDGF is induced by TKT and STAT3, impacting the STAT3-Tyr705 and STAT3-Ser727 phosphorylation and STAT3 transcriptional activity. Notably, HDGF depletion renders radioresistant hypersensitive to the drug that targets STAT3 phosphorylation. This article demonstrates the novel function of HDGF as a promising molecular target for predicting radioresistance in breast cancer.

The relationship between hepatoma-derived growth factor and prognosis in non-small cell lung cancer: A systematic review and meta-analysis

BACKGROUND

Hepatoma-derived growth factor (HDGF) promotes cancer progression and metastasis by interacting with vascular endothelial growth factor, thereby inducing epithelial-to-mesenchymal transition and angiogenesis. Recent studies have correlated increased HDGF levels with poor prognosis in various malignancies, including lung cancer. This meta-analysis systematically assessed the prognostic significance of HDGF expression in patients with non-small cell lung cancer (NSCLC).

METHODS

Eligible studies were identified by searching literature in PubMed, Embase, Scopus, and the Cochrane library until June 2020. The pooled hazard ratio (HR) or odds ratio (OR) with 95% confidence interval (CI) was determined to assess the relationship between HDGF expression and clinical outcome in patients with NSCLC.

RESULTS

The pooled HRs between high HDGF expression and clinical outcome were 2.20 (95% CI 1.75-2.76, P < .001) and 2.77 (95% CI 1.79-4.29, P < .001) for overall survival and disease-free survival, respectively. High HDGF expression was significantly correlated with a larger tumor size (OR 1.59, 95% CI 1.02-2.46, P = .040).

CONCLUSION

HDGF expression is related to clinical outcome and may be a prognostic marker in patients with NSCLC.

Long intergenic non‑coding RNA LINC01232 contributes to esophageal squamous cell carcinoma progression by sequestering microRNA‑654‑3p and consequently promoting hepatoma‑derived growth factor expression

Long intergenic non-coding RNA 01232 (LINC01232) was identified as a critical regulator of the development of pancreatic adenocarcinoma. The present study investigated the expression and regulatory roles of LINC01232 in esophageal squamous cell carcinoma (ESCC). The main aim of the present study was to elucidate the underlying mechanisms through which LINC01232 affects the malignancy of ESCC. Initially, LINC01232 expression in ESCC was analyzed using the TCGA and GTEx databases and was confirmed using reverse transcription-quantitative polymerase chain reaction. ESCC cell proliferation, apoptosis and migration and invasion were assessed using the Cell Counting kit-8 assay, flow cytometric analysis, and migration and invasion assays, respectively. ESCC tumor growth in vivo was examined using a xenograft mouse model. As shown by the results, a high LINC01232 expression was detected in ESCC tissues and cell lines. LINC01232 downregulation suppressed the proliferation, migration and invasion of ESCC cells, and promoted cell apoptosis in vitro. In addition, LINC01232 depletion restricted tumor growth in vivo. Mechanistically, LINC01232 was shown to function as an microRNA-654-3p (miR-654-3p) sponge in ESCC cells, and hepatoma-derived growth factor (HDGF) was identified as a direct target of miR-654-3p. LINC01232 could bind competitively to miR-654-3p and decrease its expression in ESCC cells, thereby promoting HDGF expression. Rescue experiments reconfirmed that the effects of LINC01232 deficiency in ESCC cells were restored by increasing the output of the miR-654-3p/HDGF axis. On the whole, the present study demonstrates that LINC01232 plays a tumor-promoting role during the progression of ESCC by regulating the miR-654-3p/HDGF axis. The LINC01232/miR-654-3p/HDGF pathway may thus provide a novel theoretical basis for the management of ESCC.

Hepatoma-Derived Growth Factor: An Overview and Its Role as a Potential Therapeutic Target Molecule for Digestive Malignancies

Hepatoma-derived growth factor (HDGF) was identified in research seeking to find a novel growth factor for hepatoma cells. Subsequently, four HDGF-related proteins were identified, and these proteins are considered to be members of a new gene family. HDGF has a growth-stimulating role, an angiogenesis-inducing role, and a probable anti-apoptotic role. HDGF is ubiquitously expressed in non-cancerous tissues, and participates in organ development and in the healing of damaged tissues. In addition, the high expression of HDGF was reported to be closely associated with unfavorable clinical outcomes in several malignant diseases. Thus, HDGF is considered to contribute to the development and progression of malignant disease. We herein provide a brief overview of the factor and its functions in relation to benign and malignant cells. We also describe its possible role as a target molecule for digestive malignancies.

Novel HDGF/HIF-1α/VEGF axis in oral cancer impacts disease prognosis

BACKGROUND

Hepatoma-derived growth factor (HDGF) participates in angiogenesis and represents a negative prognostic factor in oral cancer. The current study was designed to elucidate the regulatory mechanism between HDGF and vascular endothelial growth factor (VEGF) and the clinical impact of oral cancer.

METHODS

TCGA data and surgical samples from oral cancer patients were used for the clinicopathological parameter and survival analysis. Human oral cancer SCC4 and SAS cells were treated with recombinant HDGF protein. VEGF gene expression and protein level were analyzed by RT-PCR, Western blotting, and enzyme-linked immunosorbent assay. The signaling pathways for regulating VEGF expression were investigated. The nucleolin neutralizing antibody and HIF-1α inhibitor were applied to SCC4 cells to investigate their effects on the HDGF-stimulated VEGF pathways.

RESULTS

TCGA and immunohistochemical analysis revealed a positive correlation between HDGF and VEGF expression in oral cancer tissues. Recombinant HDGF significantly increased VEGF gene and protein expression in oral cancer SCC4 cells in a dose-dependent manner. HDGF enhanced the phosphorylation levels of AKT and IkB and the protein level of HIF-1α and NF-κB. The nucleolin-neutralizing antibody abolished HDGF-stimulated HIF-1α, NF-κB and VEGF protein expression in SCC4 cells. The HIF-1α inhibitor antagonized the HDGF-induced VEGF gene expression. High VEGF expression was strongly correlated with HDGF expression, advanced disease, and poor survival.

CONCLUSION

This study postulated a new pathway in which HDGF activated HIF-1α and then induced VEGF expression through binding to membrane nucleolin under normoxic conditions, leading to poor disease control. The HDGF/HIF-1α/VEGF axis is important for developing future therapeutic strategies.

Hepatoma-Derived Growth Factor and DDX5 Promote Carcinogenesis and Progression of Endometrial Cancer by Activating β-Catenin

Background: Our previous work determined the correlation between high nuclear expression of hepatoma-derived growth factor (HDGF) and clinicopathological data of endometrial cancer (EC); however, the modulatory mechanisms and biological role of HDGF in EC have not been reported.

Methods: Lentiviral particles carrying human HDGF short hairpin RNA (shHDGF-1, -2, and -3) vector and plasmids for HDGF, DDX5, and β-catenin expression were, respectively introduced into EC cells to evaluate the effects and molecular mechanisms underlying EC cell proliferation, migration, invasion, and metastasis. Quantitative real time reverse transcription polymerase chain reaction (qRT-PCR) and western blotting were used to determine HDGF and DDX5 expression. Co-immunoprecipitation (co-IP), mass spectrometry, and an immunofluorescence co-localization study were conducted to explore the relationship between HDGF, DDX5, and β-catenin. Immunohistochemistry was used to analyze the clinical associations between HDGF and DDX5 in EC.

Results: Knocking down HDGF expression significantly decreased EC cellular proliferation, migration, invasion in vitro, as well as tumorigenesis and metastasis in vivo. Conversely, HDGF overexpression reversed these effects. Stable knockdown-based HDGF suppression activated the PI3K/AKT signaling pathway, along with downstream β-catenin-mediated cell cycle and epithelial-mesenchymal transition signaling. Furthermore, co-IP combined with mass spectrometry and an immunofluorescence co-localization study indicated that HDGF interacts with DDX5, whereas β-catenin was associated with DDX5 but not HDGF. Overexpression of DDX5 reversed the suppression of shHDGF. Immunohistochemistry analysis showed that high expression of DDX5 constituted an unfavorable factor with respect to the clinicopathological characteristics of EC tissues and that HDGF and DDX5 high expression (HDGF+/DDX5+) led to a worse prognosis for patients with EC (P < 0.001). In addition, we found that the expression of HDGF and DDX5 was positively correlated in EC tissues (r = 0.475, P < 0.001).

Conclusion: Our results provide novel evidence that HDGF interacts with DDX5 and promotes the progression of EC through the induction of β-catenin.

Hepatoma-derived growth factor functions as an unfavorable prognostic marker of human gliomas

Hepatoma-derived growth factor (HDGF) regulates various cellular processes involved in the onset and development of tumors. To evaluate the role of HDGF in human gliomas, western blotting analysis, immunohistochemistry staining and reverse transcription-quantitative polymerase chain reaction were performed to detect HDGF protein and mRNA expression levels in glioma and intractable epileptic brain tissue. Various clinicopathological characteristics, including age, gender, World health Organization grade, HDGF expression level, Karnofsky performance Status (KPS) and Ki-67 index were obtained from medical records. The correlation between HDGF expression and these clinicopathological characteristics was statistically evaluated. Following this, multivariate liner regression was used to evaluate their effect on patient survival time. HDGF expression, at the protein and mRNA levels, was observed to be more upregulated in glioma tissues compared with intractable epileptic brain tissue without tumor. Furthermore, the level of HDGF expression was positively associated with the grade of malignancy [grades II~IV, Ki-67 index ≥20% or KPS <80 (P<0.05)] and poor prognosis in glioma patients. Notably, the univariate survival analysis identified a negative correlation between HDGF-expression and survival time (P<0.01) and multivariate liner regression demonstrated that HDGF expression is an independent prognostic factor for gliomas (P=0.01). Overall, HDGF upregulation may be a crucial step in the development and invasion of glioma. Further survival analysis highlighted its prognostic value for this malignancy, implying its potential as a promising therapeutic target for gliomas.

Downregulated expression of hepatoma-derived growth factor inhibits migration and invasion of prostate cancer cells by suppressing epithelial-mesenchymal transition and MMP2, MMP9

Hepatoma-derived growth factor (HDGF) is commonly over-expressed and plays critical roles in the development and progression in a variety of cancers. It has previously been shown that HDGF is overregulated in prostate cancer cells compared to normal prostate cells, which is correlated with cellular migration and invasion of prostate cancer. Here, the molecular mechanisms of HDGF in prostate cancer is investigated. It is shown that HDGF knockdown reduces prostate cancer cellular migration and invasion in both androgen-sensitive LNCaP cells and androgen-insensitive DU145 and PC3 cells. Furthermore, Western blot analysis reveals that HDGF knockdown inhibits epithelial-mesenchymal transition (EMT) of prostate cancer cells by upregulation of protein E-cadherin and downregulation of proteins N-cadherin, Vimentin, Snail and Slug. In addition, mechanistic studies reveal that proteins MMP2 and MMP9 are down-regulated. In conclusion, our data suggested that HDGF knockdown inhibits cellular migration and invasion in vitro of prostate cancer via modulating epithelial-mesenchymal transition (EMT) signaling pathway, as well as MMP2 and MMP9 signaling pathway. These results supported that HDGF is a relevant protein in the progression of prostate cancer and may serve as a potentially therapeutic target for prostate cancer as well as its downstream targets.

Hepatoma-derived Growth Factor Predicts Disease Severity and Survival in Pulmonary Arterial Hypertension

RATIONALE

Pulmonary arterial hypertension (PAH) is a fatal disease, and pulmonary microvascular remodeling is an important contributor to PAH development. Therefore, we hypothesized that a circulating angiogenic factor could predict disease severity and survival.

OBJECTIVES

We sought to assess the relationship of serum hepatoma-derived growth factor (HDGF) with PAH disease severity and survival.

METHODS

Using a newly developed enzyme-linked immunosorbent assay, we evaluated circulating HDGF levels in two independent PAH cohorts and two different characterized control cohorts. Clinical and laboratory data were also used to assess the value of HDGF as a PAH prognostic biomarker.

MEASUREMENTS AND MAIN RESULTS

Serum HDGF levels were significantly elevated in two independent PAH cohorts. Importantly, serum HDGF levels were not elevated in a noncardiac chronic disease cohort. Further, patients with elevated HDGF had significantly lower exercise tolerance, worse New York Heart Association functional class, and higher levels of N-terminal pro-brain natriuretic peptide. HDGF was a strong predictor of mortality, with an unadjusted hazard ratio of 4.5 (95% confidence interval, 1.9-10.3; P = 0.003 by log-rank test). In multivariable Cox proportional hazards models, elevated HDGF levels predicted decreased survival after being adjusted for age, PAH subtype, invasive hemodynamics, and N-terminal pro-brain natriuretic peptide.

CONCLUSIONS

Elevated HDGF was associated with worse functional class, exertional intolerance, and increased mortality in PAH, suggesting HDGF as a potential biomarker for predicting mortality and as having possible diagnostic value for distinguishing PAH from non-PAH. HDGF may add additional value in PAH risk stratification in clinical trials and may represent a potential target for future PAH drug development.

Hepatoma-derived growth factor promotes growth and metastasis of hepatocellular carcinoma cells

We aimed to elucidate the effects of hepatoma-derived growth factor (HDGF) on growth and metastasis of hepatocellular carcinoma (HCC) cells. Tissue microarrays with 236 HCC specimens and 18 extrahepatic metastases were utilized to detect the HDGF expression by immunohistochemistry. Meanwhile, HDGF expressions in HCC cell lines with different metastatic potentials were examined using immunofluorescence staining, real-time PCR and western blotting. After HDGF silencing, the growth and metastatic potentials of HCC cells were evaluated by soft agar assay, invasion assay, together with tumorigenicity assay in nude mice. The gelatin zymography was performed by detecting MMP-2 and MMP-9 levels. Additionally, western blotting was conducted to determine the levels of total and phosphorylated ERK1/2, JNK, p38 and Akt. The results showed that HDGF was overexpressed in HCC metastasis tumour, and the expression increased with the differentiation degree of tumours (Grade I 44.0%, Grade II 48.4% and Grade III 65.6%). Consistently, HDGF levels were positively associated with the metastatic capability of HCC cells (MHCC97L < MHCC97H < HCCLM3). The growth and metastasis were suppressed by HDGF-siRNA. Gelatinolytic activities were enhanced in the three metastatic HCC cell lines, but had no significant difference among them. The tumourigenicity and metastatic capability of HCCLM3 cells in nude mice were inhibited after silencing HDGF. Meanwhile, HDGF-siRNA specifically suppressed the total and phosphorylated protein levels of ERK1/2, while not JNK, p38 and Akt. In conclusion, HDGF was overexpressed in HCC patients and cells, and HDGF might be closely correlated with HCC metastasis via regulating ERK signalling pathway. Copyright © 2016 John Wiley & Sons, Ltd.

The evaluation of hepatoma-derived growth factor in determining of prognosis and estimating of invasive probability of tumoral cells, recurrent, and metastasis of lymphatic glands in breast carcinoma

Introduction:

Recently, hepatoma-derived growth factor (HDGF) has been considered as a significantly important factor in determining the prognosis and estimating the probability of tumor cell invasions, recurrence, and lymph node metastasis in different cancers, including breast malignancies.

Materials and Methods:

Immunohistochemistry (IHC) study for HDGF was performed on paraffin-embedded blocks of patients with breast carcinoma in Modarres hospital, Tehran, Iran, since 1387–1390 (74 cases); three separate pathologists read the slides after complete IHC staining. Thereafter, necessary information was recorded from patient files, and eventually, findings were analyzed by SPSS program.

Results:

Expression of nuclear HDGF has significant statistical correlation with tumor grade according to Nottingham grading scheme; this correlation is also seen with nuclear pleomorphism of tumor cells and mitotic count. No correlation between age and tumor size with expression of HDGF is found. Lymph node metastasis is in inverse ratio to nuclear HDGF staining.

Conclusion:

Nuclear expression of HDGF in tumor cells is increased concordantly to tumor grade, which implies us to the role of this marker in determining the prognosis and choosing the most suitable treatment plan.

Positive feedback loop of hepatoma-derived growth factor and β-catenin promotes carcinogenesis of colorectal cancer

To clarify the role of hepatoma-derived growth factor (HDGF) and β-catenin in carcinogenesis of colorectal cancer (CRC), our results showed that high HDGF expression was found in CRC cells and tissues and significantly related to histological differentiation (p = 0.035) and lymph node metastasis (p = 0.000). Significant positive correlation between HDGF expression and β-catenin abnormal expression was found in CRC tissues. High HDGF and lymph node metastasis were the strong independent prognostic indicators for reduced overall survival in CRC patients. HDGF knockdown dramatically inhibited cellular proliferation, migration, invasion, and tumorigenesis, both in vitro and in vivo, but induced G1 phase arrest and apoptosis in CRC cells. HDGF knock-down dramatically suppressed β-catenin and its down-stream genes expression in CRC cells. Intriguingly, β-catenin knock-down dramatically suppressed HDGF expression in CRC cells. Human recombinant Wnt3a and DKK1 treatment increased and decreased HDGF, β-catenin, c-Myc, cyclin D1, MMP9, and phos-GSK-3β (Ser9) protein expression in nuclear and cytoplasmic fraction of CRC cells upon β-catenin knock-down, respectively. Three HDGF-binding elements in β-catenin promoter were found and specific for transcriptional activation of β-catenin in CRC cells. In conclusion, our results first suggest that HDGF and β-catenin interacts as a positive feedback loop, which plays an important role in carcinogenesis and progression of CRC.

Hepatoma derived growth factor (HDGF) dynamics in ovarian cancer cells

As a leading cause of cancer death among women, identification of pathophysiologically-relevant biomarkers for ovarian cancer is important. The heparin binding, hepatoma-derived growth factor (HDGF) is overexpressed in ovarian cancer cell lines and may have prognostic value, but the mechanism by which this predominantly nuclear protein is secreted or functions is unknown. In this study, we focused on the circumstances under which HDGF is released by cells and the functional relevance of extracellular HDGF in the context of ovarian cancer. Immunofluorescence imaging showed nuclear localization of HDGF in ovarian cells, but unlike what is reported for other cell types, HDGF was minimally secreted into the media. However, HDGF was passively released by necrotic and late apoptotic cells. Extracellular HDGF was functionally relevant as it stimulated phosphorylation of ERK 1/2 and P38 in both non-cancer and ovarian cancer cells, and enhanced cellular migration. Overall, our study uncovers a novel function of HDGF as a messenger of cellular condition (alarmin) which in-turn modulates cellular function-aspects that could be used as a biomarker for ovarian cancer.

Prognostic role of hepatoma-derived growth factor in solid tumors of Eastern Asia: a systematic review and meta- analysis

Hepatoma-derived growth factor (HDGF) is a novel jack-of-all-trades in cancer. Here we quantify the prognostic impact of this biomarker and assess how consistent is its expression in solid tumors. A comprehensive search strategy was used to search relevant literature updated on October 3, 2014 in PubMed, EMBASE and WEB of Science. Correlations between HDGF expression and clinicopathological features or cancer prognosis was analyzed. All pooled HRs or ORs were derived from random-effects models. Twenty-six studies, primarily in Eastern Asia, covering 2,803 patients were included in the analysis, all of them published during the past decade. We found that HDGF overexpression was significantly associated with overall survival (OS) (HROS=2.35, 95%CI=2.04-2.71, p<0.001) and disease free survival (DFS) (HRDFS=2.25, 95%CI =1.81-2.79, p<0.001) in solid tumors, especially in non-small cell lung cancer, hepatocellular carcinoma and cholangiocarcinoma (CCA). Moreover, multivariate survival analysis showed that HDGF overexpression was an independent predictor of poor prognosis (HROS=2.41, 95%CI: 2.02-2.81, p<0.001; HRDFS=2.39, 95%CI: 1.77-3.24, p<0.001). In addition, HDGF overexpression was significantly associated with tumor category (T3-4 versus T1-2, OR=2.12, 95%CI: 1.17-3.83, p=0.013) and lymph node status (N+ versus N-, OR=2.37, 95%CI: 1.31-4.29, p=0.03) in CCA. This study provides a comprehensive examination of the literature available on the association of HDGF overexpression with OS, DFS and some clinicopathological features in solid tumors. Meta-analysis results provide evidence that HDGF may be a new indicator of poor cancer prognosis. Considering the limitations of the eligible studies, other large-scale prospective trials must be conducted to clarify the prognostic value of HDGF in predicting cancer survival.

Hepatoma-derived growth factor-2 is highly expressed during development and in spinal cord injury

Hepatoma‑derived growth factor‑2 (HDGF‑2) is expressed in neurons, astrocytes and oligodendrocytes of the adult mouse brain. However, it has remained elusive whether HDGF‑2 is expressed in the spinal cord and is involved in the its development and repair. In the present study, the expression of HDGF‑2 was investigated in rat spinal cords at different developmental stages and following spinal cord injury (SCI). Protein levels of HDGF‑2 were examined using western blot analysis, while the distribution pattern and cell populations of HDGF‑2 protein expression were characterized using immunohistochemistry. Western blot analysis demonstrated that the levels of HDGF‑2 protein expression were the greatest in the spinal cord on embryonic day 19, and were also highly expressed in rat spinal cords on post‑natal day 7 (P7); however, they were low at P14 and not detectable at two months. HDGF‑2 expression was significantly upregulated in the embryonic spinal cord and injured spinal cord. By contrast, the expression of HDGF‑2 was low in uninjured adult spinal cords. HDGF‑2 expression in the fetal rat spinal cord and injured spinal cord was significantly higher than that in uninjured adult spinal cord tissues (P<0.05). The number of cells positive for HDGF‑2 was 141±62, 107±33 and 92±18 at days 1, 21 and 45 following SCI, respectively, as opposed to 50±9 in uninjured rats, and a significant difference was identified between the different time‑points following SCI (P<0.01). In conclusion, the overexpression of HDGF‑2 in the embryonic spinal cord and injured spinal cord may be involved in fetal spinal cord development and repair of SCI, respectively.

Differential proteomic analysis reveals that EGCG inhibits HDGF and activates apoptosis to increase the sensitivity of non-small cells lung cancer to chemotherapy

PURPOSE

To search for regulated proteins in response to green tea (-)-epigallocatechin-3-gallate (EGCG) in A549 lung cancer cells.

EXPERIMENTAL DESIGN

2DE and ESI/multistage MS (ESI-MS/MS) were performed to identify modulated proteins in A549 cells treated with EGCG. Cell migration was evaluated by transwell assays. RNA interference was used to silence the hepatoma-derived growth factor (HDGF). Caspase-3, caspase-9, and HDGF were immunodetected by Western blot assays. Flow cytometry was used for detection of mitochondrial membrane potential and apoptosis.

RESULTS

We found that HDGF expression was threefold suppressed by EGCG treatment. Downregulation of HDGF by EGCG was confirmed using anti-HDGF antibodies in three lung cancer cell lines. EGCG treatment and HDGF abrogation by RNA interference resulted in a decreased migration of A549 cells. In addition, EGCG induced a marked synergistic effect with cisplatin in cell death. Consistently, an enhanced cytotoxicity in HDGF-silenced cells was also found. Cell death was associated to increased apoptosis, disruption of the mitochondrial membrane potential, and activation of caspase-3 and caspase-9.

CONCLUSION AND CLINICAL RELEVANCE

Our data suggest for the first time that abrogation of HDGF by EGCG enhances cisplatin-induced apoptosis and sensitize A549 cells to chemotherapy. Therefore, we propose that decreasing the HDGF levels by using EGCG may represent a novel strategy in lung cancer therapy.

The expression and clinical significance of HDGF in osteosarcoma

AIM

To investigate the expression of hepatoma-derived growth factor (HDGF) in osteosarcoma (OS) and the correlation with clinicopathologic factors, prognosis, and tumor progression.

METHOD

HDGF expression in OS tissues was detected by immunohistochemistry. The correlation between HDGF and clinicopathologic factors was analyzed by chi-square test, and the association between HDGF expression and the overall survival rates was evaluated by univariate analysis using Kaplan-Meier method. HDGF concentration in cell medium or cell lysates was detected by enzyme-linked immunosorbent assay method. The effect of extrinsic and intrinsic HDGF on OS cell proliferation was detected by MTT assay after recombinant HDGF stimulation or HDGF knockdown, respectively.

RESULTS

Proportion of HDGF high expression was 18.69% (20/107) in OS. HDGF high expression was significantly associated with larger tumor size (P=0.004). With experiments in vitro, we demonstrated that human recombinant HDGF could activate AKT and MAPK signaling pathway, resulting in OS cell proliferation. By knocking down HDGF expression, we proved that intrinsic HDGF was required in OS proliferation.

CONCLUSION

High HDGF expression was significantly associated with larger OS tumor size and could promote OS cell proliferation, indicating that HDGF could be an effective biomarker and a potential drug target in OS treatment.

HDGF: a novel jack-of-all-trades in cancer

HDGF is an important regulator of a broad range of cancer cell activities and plays important roles in cancer cell transformation, apoptosis, angiogenesis and metastasis. Such a divergent influence of HDGF on cancer cell activities derives from its multiple inter- and sub-cellular localizations where it interacts with a range of different binding partners. Interestingly, high levels of HDGF could be detected in patients' serum of some cancers. This review is focused on the role of HDGF in tumorigenesis and metastasis, and provides insight for application in clinical cancer therapy as well as its clinical implications as a prognostic marker in cancer progression.

Hepatoma-derived growth factor expression as a prognostic marker in cervical cancer

AIM: To examine the association of hepatoma-derived growth factor (HDGF) expression with the prognosis of patients with cervical cancer of the uterus (CC).

METHODS: HDGF is a unique nuclear growth factor, and it may play an important role in the development and progression of carcinoma. HDGF expression in 88 CC patients aged 23 to 76 years (median, 54 years) was analyzed by immunohistochemistry. A rabbit polyclonal antibody against the C-terminal amino acids (aa 231-240) of the human HDGF sequence was used as primary antibody at a dilution of 1:5000. This specific anti-HDGF antibody was purified using C-terminal peptide-conjugated Sepharose columns. Staining of endothelial cells in the noncancerous areas of each specimen was used as an internal positive control. Samples with more than 80% of tumor cells showing positive immunoreactivity in both the nucleus and cytoplasm were regarded as HDGF index level 2, more than 80% positive immunoreactivity in either the nucleus or cytoplasm as level 1, and less than 80% in both the nucleus and cytoplasm as level 0. The chi-square test and Fisher’s exact probability test were used to examine the relationship between HDGF expression and clinicopathologic parameters, and statistical significance was examined by the log-rank test. Multivariate analysis of factors related to survival was performed using Cox’s proportional hazards regression model. Statistical significance was set at P < 0.05.

RESULTS: The five-year overall survival rate was 82.9%. Fourteen patients died due to tumors, nine of whom had tumor recurrence at 2-21 mo (median, 10 mo) after surgery. Tumor recurrence in five patients was determined at the time of the patients’ deaths. Nineteen cases were regarded as HDGF index level 0, 11 as level 1, and 58 as level 2. Patients with level 2 expression showed higher rates of histological classification of keratinized squamous cell carcinoma and adenosquamous carcinoma (44.8% of level 2 patients and 13.3% in levels 0 and 1), deep invasion (pT2-4 in 65.5% of level 2 patients, and 30.0% in levels 0 and 1), the presence of lymphatic invasion (50.0% in level 2, and 20.0% in levels 0 and 1), and the presence of lymph node metastasis (37.9% in level 2, and 6.7% in levels 0 and 1). Patients with an HDGF index of level 2 CC showed poorer 5-year overall survival rates than those with level 0 or 1 CC (74.0% and 100%, respectively, P = 0.0036). Univariate analysis revealed that histological classification (P = 0.04), depth of tumor invasion (P = 0.0001), vascular invasion (P = 0.004), and lymph node metastasis (P = 0.0001) were significant factors affecting overall survival in addition to HDGF expression. Multivariate analysis revealed HDGF expression level and lymph node metastasis as independent prognostic factors for overall survival (P = 0.0148 and P = 0.0197, respectively). The prognostic significance of HDGF was further analyzed in pT1 and pT2-4 patient groups, respectively. Among patients with pT1 CC, one the 39 analyzed patients died during the study, and no difference was observed among patients with HDGF index level 0, 1, or 2 CC. However, prognostic significance of the HDGF index was observed in the pT2-4 patient group, in which the mortality rates of patients with HDGF index level 2 CC and those with level 0 or 1 CC significantly differed (P = 0.0463).

CONCLUSION: The HDGF expression level is of prognostic significance in CC.

Irradiated fibroblasts promote epithelial-mesenchymal transition and HDGF expression of esophageal squamous cell carcinoma

Recent evidence suggested that nonirradiated cancer-associated fibroblasts (CAFs) promoted aggressive phenotypes of cancer cells through epithelial-mesenchymal transition (EMT). Hepatoma-derived growth factor (HDGF) is a radiosensitive gene of esophageal squamous cell carcinoma (ESCC). This study aimed to investigate the effect of irradiated fibroblasts on EMT and HDGF expression of ESCC. Our study demonstrated that coculture with nonirradiated fibroblasts significantly increased the invasive ability of ESCC cells and the increased invasiveness was further accelerated when they were cocultured with irradiated fibroblasts. Scattering of ESCC cells was also accelerated by the supernatant from irradiated fibroblasts. Exposure of ESCC cells to supernatant from irradiated fibroblasts resulted in decreased E-cadherin, increased vimentin in vitro and β-catenin was demonstrated to localize to the nucleus in tumor cells with irradiated fibroblasts in vivo models. The expression of HDGF and β-catenin were increased in both fibroblasts and ESCC cells of irradiated group in vitro and in vivo models. Interestingly, the tumor cells adjoining the stromal fibroblasts displayed strong nuclear HDGF immunoreactivity, which suggested the occurrence of a paracrine effect of fibroblasts on HDGF expression. These data suggested that irradiated fibroblasts promoted invasion, growth, EMT and HDGF expression of ESCC.

Prognostic significance of nuclear hepatoma-derived growth factor expression in gallbladder cancer

AIM: To assess the expression of nuclear hepatoma-derived growth factor (HDGF) in benign and malignant gallbladder lesions and to determine its clinicopathological significance.

METHODS: We studied 40 patients with gallbladder cancer (GBC) and a control group of 40 patients with cholelithiasis. All diagnoses of GBC and cholelithiasis were confirmed by histopathological examination after surgery. None of the patients received chemotherapy or radiotherapy before surgery. All tissue samples were fixed in 4% formalin immediately after removal and embedded in paraffin for immunohistochemical staining. The HDGF expression in the GBC and cholelithiasis specimens was examined by immunohistochemical staining. The relationship between the HDGF expression and the clinicopathological parameters of GBC was analyzed.

RESULTS: Nuclear HDGF expression was significantly higher (77.5%) in GBC than in chronic cholelithiasis (21.5%, P < 0.001). High nuclear HDGF levels were associated with histopathological subtype (P < 0.05), clinical stage (P < 0.01), and perineural invasion (P < 0.01) but not with sex, age, history of gallstones, or lymph node metastasis. A univariate Kaplan-Meier analysis showed that positive nuclear HDGF expression was associated with decreased overall survival (P < 0.01). Multivariate Cox regression analysis showed that nuclear HDGF expression and lymph node metastasis were independent risk factors for disease-free survival.

CONCLUSION: The expression of nuclear HDGF might be closely related to the carcinogenesis, clinical biological behaviors, and prognosis of gallbladder adenocarcinoma.

p53 and hepatoma-derived growth factor expression and their clinicopathological association with Ewing family tumour

PURPOSE

To investigate p53 and hepatoma-derived growth factor (HDGF) expression and their association with clinicopathological features of Ewing family tumour (EFT).

EXPERIMENTAL DESIGN

A total of 108 cases of EFT were retrospectively analysed. p53 and HDGF expression were detected using immunohistochemistry, and the relationships between p53 expression and HDGF expression and clinicopathological features of EFT were analysed. Kaplan-Meier curves were applied to estimate overall survival, log-rank test was used to assess prognostic relevance of p53 expression with overall survival and Cox regression model was performed to evaluate HRs.

RESULTS

p53 expression and high HDGF expression was found in 17 (15.7%) and 55 (50.9%) patients, respectively. p53 expression was significantly associated with metastatic stage at initial diagnosis (p=0.007) and tumour venous/nerve invasion (p=0.023). A significant positive correlation was found between p53 expression and HDGF expression in EFT (p=0.022). p53 expression was an independent prognostic factor for overall survival of patients with EFT (p<0.001). Patients with p53-positive/high HDGF expression had a significantly shorter overall survival than those with p53-positive/low HDGF expression or p53-negative/high HDGF expression or p53-negative/low HDGF expression. We first constructed a novel molecular staging system by combining p53 expression and HDGF expression, which significantly improved prognostic stratification for patients with EFT.

CONCLUSIONS

p53 expression was an independent prognostic factor for patients with EFT. Combining p53 expression and HDGF expression significantly improved prognostic stratification for patients with EFT.

Clinical and biological significance of hepatoma-derived growth factor in Ewing's sarcoma

We sought to investigate the clinicopathological significance and biological function of hepatoma-derived growth factor (HDGF) in Ewing's sarcoma. Our results showed that HDGF expression is up-regulated in Ewing's sarcoma. Nuclear HDGF expression is significantly associated with tumour volume (p < 0.001), metastases at diagnosis (p < 0.001), low overall survival rate (p < 0.001) and low disease-free survival rate (p < 0.001). HDGF knock-down results in significant reduction of Ewing's sarcoma cell growth, proliferation and enhances tumourigenesis, both in vitro and in vivo. Meanwhile, HDGF knock-down causes cell cycle arrest and enhanced sensitization to serum starvation-induced apoptosis. Furthermore, recombinant HDGF promotes proliferation and colony formation of Ewing's sarcoma cells. Ninety-eight candidate HDGF downstream genes were identified in Ewing's sarcoma cells using cDNA microarray analysis. In addition, we found that HDGF knock-down inhibited FLI1 expression in Ewing's sarcoma cells at the mRNA and protein levels. Our findings suggest that HDGF exhibits oncogenic properties and may be a novel prognostic factor in Ewing's sarcoma. Targeting HDGF might be a potential therapeutic strategy for Ewing's sarcoma.

Downregulated expression of hepatoma-derived growth factor (HDGF) reduces gallbladder cancer cell proliferation and invasion

Hepatoma-derived growth factor (HDGF), a heparin-binding growth factor, has a wide range of biological functions, including mitogenic activity and vascular development. Recent studies demonstrated that HDGF also acted as an oncogene with aberrantly increased activity in multiple human cancers; however, little is known about the biological function of HDGF in gallbladder cancer (GBC). In this study, we focused on the clinical significance and biological functions of HDGF in GBC and found that Nuclear HDGF protein overexpression was frequently detected in GBC tissues. Patients with nuclear HDGF-positive tumors had worse overall survival than patients with HDGF-negative tumors. Furthermore, treatment of GBC lines with HDGF-targeting siRNA oligonucleotides (HDGF-siRNA) significantly reduced the proliferation of GBC-SD and SGC-996 cell lines and diminished both anchorage-independent growth on soft agar and cell migration. These data indicate that HDGF acts as a putative oncogene in GBC and could be a novel diagnostic and therapeutic target for GBC.

Up-regulation of hepatoma-derived growth factor facilitates tumor progression in malignant melanoma [corrected]

Cutaneous malignant melanoma is the fastest increasing malignancy in humans. Hepatoma-derived growth factor (HDGF) is a novel growth factor identified from human hepatoma cell line. HDGF overexpression is correlated with poor prognosis in various types of cancer including melanoma. However, the underlying mechanism of HDGF overexpression in developing melanoma remains unclear. In this study, human melanoma cell lines (A375, A2058, MEL-RM and MM200) showed higher levels of HDGF gene expression, whereas human epidermal melanocytes (HEMn) expressed less. Exogenous application of HDGF stimulated colony formation and invasion of human melanoma cells. Moreover, HDGF overexpression stimulated the degree of invasion and colony formation of B16–F10 melanoma cells whereas HDGF knockdown exerted opposite effects in vitro. To evaluate the effects of HDGF on tumour growth and metastasis in vivo, syngeneic mouse melanoma and metastatic melanoma models were performed by manipulating the gene expression of HDGF in melanoma cells. It was found that mice injected with HDGF-overexpressing melanoma cells had greater tumour growth and higher metastatic capability. In contrast, mice implanted with HDGF-depleted melanoma cells exhibited reduced tumor burden and lung metastasis. Histological analysis of excised tumors revealed higher degree of cell proliferation and neovascularization in HDGF-overexpressing melanoma. The present study provides evidence that HDGF promotes tumor progression of melanoma and targeting HDGF may constitute a novel strategy for the treatment of melanoma.

Downregulation of hepatoma-derived growth factor contributes to retarded lung metastasis via inhibition of epithelial-mesenchymal transition by systemic POMC gene delivery in melanoma

The prognosis of malignant melanoma is poor due to high incidence of metastasis, underscoring the demand for development of novel therapeutic strategies. Stress hormone pro-opiomelanocortin (POMC) is the precursor for several anti-inflammatory peptides that hold promise for management of cancer-related diseases. The present study evaluated the antimetastatic potential and mechanism of POMC therapy for metastatic melanoma. Adenovirus-mediated POMC gene delivery potently inhibited the invasiveness of human and mouse melanoma cells. Moreover, after induction of lung metastasis, systemic POMC expression significantly reduced the foci formation and neovascularization in lungs. Mechanistic studies revealed that POMC therapy inhibited the epithelial-mesenchymal transition (EMT) of melanoma cells by upregulation of E-cadherin and downregulation of vimentin and α-smooth muscle actin (α-SMA). In addition, microarray analysis unveiled POMC gene transfer reduced the mRNA level of multiple prometastatic factors, including hepatoma-derived growth factor (HDGF). Cell culture and immunohistochemical studies further confirmed that POMC gene delivery significantly decreased the expression of HDGF in melanoma cells and tissues. Despite stimulating the invasion and EMT, exogenous HDGF supply only partially attenuated the POMC-mediated invasion inhibition and EMT change in melanoma cells. Finally, we delineated the contribution of melanocortins to POMC-induced inhibition of invasion, HDGF downregulation, and E-cadherin upregulation. Together, these results indicate that HDGF downregulation participates in POMC-induced suppression of metastasis and EMT in melanoma.

Hepatoma-derived growth factor and nucleolin exist in the same ribonucleoprotein complex

BACKGROUND

Hepatoma-derived growth factor (HDGF) is a protein which is highly expressed in a variety of tumours. HDGF has mitogenic, angiogenic, neurotrophic and antiapoptotic activity but the molecular mechanisms by which it exerts these activities are largely unknown nor has its biological function in tumours been elucidated. Mass spectrometry was performed to analyse the HDGFStrep-tag interactome. By Pull-down-experiments using different protein and nucleic acid constructs the interaction of HDGF and nucleolin was investigated further.

RESULTS

A number of HDGFStrep-tag copurifying proteins were identified which interact with RNA or are involved in the cellular DNA repair machinery. The most abundant protein, however, copurifying with HDGF in this approach was nucleolin. Therefore we focus on the characterization of the interaction of HDGF and nucleolin in this study. We show that expression of a cytosolic variant of HDGF causes a redistribution of nucleolin into the cytoplasm. Furthermore, formation of HDGF/nucleolin complexes depends on bcl-2 mRNA. Overexpression of full length bcl-2 mRNA increases the number of HDGF/nucleolin complexes whereas expression of only the bcl-2 coding sequence abolishes interaction completely. Further examination reveals that the coding sequence of bcl-2 mRNA together with either the 5' or 3' UTR is sufficient for formation of HDGF/nucleolin complexes. When bcl-2 coding sequence within the full length cDNA is replaced by a sequence coding for secretory alkaline phosphatase complex formation is not enhanced.

CONCLUSION

The results provide evidence for the existence of HDGF and nucleolin containing nucleoprotein complexes which formation depends on the presence of specific mRNAs. The nature of these RNAs and other components of the complexes should be investigated in future.

Prognostic value of nuclear hepatoma-derived growth factor (HDGF) localization in patients with breast cancer

Hepatoma-derived growth factor (HDGF) plays an important role in tumor progression. Highly expressed HDGF has been found to indicate poor prognosis in many cancers. However, no information is available regarding the prognostic value of nuclear or cytoplasmic HDGF staining level in breast cancer. In the present study, the nuclear or cytoplasmic HDGF staining level was investigated in 86 patients with primary breast cancer by immunohistochemistry; the relationship between nuclear or cytoplasmic HDGF staining level and clinicopathological parameters was examined by Two-tailed Mann-Whitney U-test or Krustal-Wallis. The prognostic value of nuclear or cytoplasmic HDGF staining level in disease-free survival and overall survival was analyzed by Kaplan-Meier methods and log-rank test. We found that the percentage of cases with strong nuclear HDGF staining level was significantly higher in the cases with high tumor grade, high stage, high proliferation index (Ki-67 index>20%), as well as in those with lymph node invasion and recurrence (p<0.05) compared to those without. No significant correlation was found between cytoplasmic HDGF expression and any clinicopathological variables. In addition, disease-free survival and overall survival were significantly lower in patients with high nuclear HDGF expression (level 2) than in those with low nuclear HDGF expression (level 0 and level 1). Further Cox multivariate analysis showed that high nuclear HDGF expression is an independent factor for indicating poor prognosis in breast cancer patients. No significant difference in disease-free survival rate and overall survival was found between different cytoplasmic HDGF staining levels. All these findings suggest that increased nuclear HDGF expression is involved in tumor progression and might be used as a new prognosticator for breast cancer.

The expression and prognostic significance of hepatoma-derived growth factor in oral cancer

Hepatoma-derived growth factor (HDGF) participates in oncogenic progression and represents a prognostic factor in several types of cancer. This study aimed to elucidate the role of HDGF during oral carcinogenesis. HDGF expression and the tumorigenic behaviors in human oral cell lines were investigated by immunoblotting, invasion and colony formation assays. Recombinant adenovirus vectors were employed to modulate the HDGF level in oral cancer cells. Immunohistochemical analysis using tissue microarray (TMA) consisting of surgically resected samples from 95 oral cancer patients was performed to delineate the correlation between HDGF expression and clinic-pathological parameters. HDGF expression was higher in malignant oral cancer cells than benign ones. Adenovirus-mediated HDGF overexpression and knockdown demonstrated the cellular HDGF level regulated the tumorigenic behaviors of oral cancer cells. Immunohistochemical analysis revealed increased HDGF expression in the nucleus and cytoplasm in oral cancer tissues. The nuclear HDGF expression was significantly correlated with tumor stage (P=0.004) and grade (P=0.013) while the cytoplasmic HDGF expression was associated with tumor necrosis (P=0.002). Kaplan-Meier analysis revealed that patients with high nuclear HDGF expression had significantly worse 5-year disease-specific survival (P=0.0069), metastasis-free survival (P=0.0168), and local recurrence-free survival (P=0.0047). Multivariate analysis indicated that the nuclear HDGF labeling index was an independent prognostic factor for disease-specific and local recurrence-free survival. HDGF overexpression contributes to the oncogenic processes in oral cancer cells and constitutes a novel prognostic factor for survival outcome of oral cancer patients.

Tumorigenesis and prognostic role of hepatoma-derived growth factor in human gliomas

Hepatoma-derived growth factor (HDGF) is a neurotrophic factor found in mouse spinal cord and hippocampal neurons. In various malignant tumors, the role of HDGF in tumor progression and its use as a diagnostic biomarker or therapeutic target have been extensively explored. However, the prognostic function and mitogenic role of HDGF in gliomagenesis are yet to be verified. In this study, we found a significant incidence of HDGF prevalence between the different pathological types and stages of glioma in 105 patients. We also found a prognostic significance in 41 glioblastoma multiforme (GBM) patients, with prevalence of nuclear HDGF predicting short survival of patients with GBM after surgery. To delineate the mitogenic role of HDGF in gliomagenesis, an adenoviral-expressed HDGF small interfering RNA (Ad-HDGF siRNA) was used to knock down expression of nuclear HDGF. After knocking down nuclear HDGF expression in human GBM cells, cell growth and cell invasion and induction on apoptosis by caspase-3 activation were significantly inhibited. We conclude that HDGF is a mitogenic growth factor in glioma progression and can be a useful prognostic marker for GBM and therapeutic target for clinical management of glioma in the future.

[Aberrant expression of HDGF and its prognostic values in surgically resected non-small cell lung cancer]

BACKGROUND AND OBJECTIVE

Our previous studies revealed that hepatoma-derived growth factor (HDGF) is highly expressed in non-small cell lung cancer (NSCLC) cells, playing important roles in promoting NSCLC cells growth and invasion. The aim of this study is to detect the expression of HDGF in 158 cases of surgically resected NSCLC and evaluate its clinical significance.

METHODS

Immunohistochemical SP method was used to detect the expression of HDGF in 158 NSCLC tissues and 12 normal control lung tissues. Survival analysis was further conducted.

RESULTS

HDGF was found significantly highly expressed in 158 NSCLC tissues compared with normal control lung tissues (P < 0.001). The 5-year survival rate was 38.2% in HDGF high expression cases, compared with 63.1% in HDGF low expression cases, the difference was statistically significant (P=0.009). Linear correlation analysis discovered a significantly negative correlation between HDGF expression and the survival time (r=-0.183, P=0.022). COX proportion hazard model analysis revealed that pathological stages and HDGF expression were independent prognostic factors for this group of 158 resected NSCLC cases.

CONCLUSIONS

HDGF is highly expressed in human NSCLC tissues, predicting worse prognosis in resected NSCLCs. It might be useful molecular biomarker for predicting the prognosis of resected NSCLCs.

Mitotic phosphorylation activates hepatoma-derived growth factor as a mitogen

Background

Hepatoma-derived growth factor (HDGF) is a nuclear protein that is a mitogen for a wide variety of cells. Mass spectrometry based methods have identified HDGF as a phosphoprotein without validation or a functional consequence of this post-translational modification.

Results

We found that HDGF in primary mouse aortic vascular smooth muscle cells (VSMC) was phosphorylated. Wild type HDGF was phosphorylated in asynchronous cells and substitution of S103, S165 and S202 to alanine each demonstrated a decrease in HDGF phosphorylation. A phospho-S103 HDGF specific antibody was developed and demonstrated mitosis-specific phosphorylation. HDGF-S103A was not mitogenic and FACS analysis demonstrated a G2/M arrest in HDGF-S103A expressing cells, whereas cells expressing HDGF-S103D showed cell cycle progression. Nocodazole arrest increased S103 phosphorylation from 1.6% to 29% (P = 0.037).

Conclusions

Thus, HDGF is a phosphoprotein and phosphorylation of S103 is mitosis related and required for its function as a mitogen. We speculate that cell cycle regulated phosphorylation of HDGF may play an important role in vascular cell proliferation.

Increased expression of hepatoma-derived growth factor correlates with poor prognosis in human nasopharyngeal carcinoma

AIMS

To examine the correlation between hepatoma-derived growth factor (HDGF) expression and clinicopathological data in nasopharyngeal carcinoma (NPC), including patient survival.

METHODS AND RESULTS

Using real-time polymerase chain reaction (PCR) and Western blot, mRNA and protein expression of HDGF was detected in normal nasopharyngeal tissues, NPC tissues and cell lines. HDGF levels were determined further by an immunohistochemical analysis in a retrospective series consisting of 160 primary NPC tissues and 71 non-cancerous nasopharynx tissues. Overexpressed mRNA and HDGF protein was present in NPC. By immunohistochemical analysis, we found that 53.8% (86 of 160) and 19.4% (32 of 160) of NPC biopsy specimens showed higher HDGF expression of the nucleus and cytoplasm, respectively. Statistical analysis showed that the higher expression of nuclear HDGF was associated significantly with T stage (P=0.005) and clinical stage (P=0.038), but there was no association with lymph node (P=0.059) or distant metastasis (P=0.563). Patients with increased HDGF expression levels had poorer overall survival rates than those with low expression of HDGF levels (P=0.006). Multivariate analysis revealed that high expression of nuclear HDGF was an independent prognostic indicator of patient survival.

CONCLUSIONS

Increased nuclear expression of HDGF is a potential unfavourable prognostic factor for patients with NPC.

Overexpressed HDGF as an independent prognostic factor is involved in poor prognosis in Chinese patients with liver cancer

BACKGROUND

Hepatoma-derived growth factor (HDGF) is involved in the hepatocarcinogenesis. In this study, we investigated the HDGF expression in hepatocellular carcinoma (HCC) and its correlation with clinicopathologic features, including the survival of patients with HCC. Furthermore, we examined the biological processes regulated by HDGF during the development of using HepG2 cell line as a model system.

METHODS

We used immunohistochemistry to compare HDGF protein expression in HCC and normal liver tissues and further analyze the HDGF protein expression in clinicopathologically characterized 137 HCC cases. We stably knocked down the endogenous expression level of HDGF in HepG2 cells with specific shRNA-expressing lentiviral vector. Following the successful establishment of stable cells, we examined in vitro cell growth by MTT assay, anchorage-independent growth by soft-agar colony formation assay and cell migration/invasion by transwell and boyden chamber assay. And in addition, we also investigated the in vivo tumor growth by xenograft transplantation of HepG2 cells into nude mice.

RESULTS

Protein expression level of HDGF was markedly higher in HCC tissues than that in the normal liver tissues(P = 0.011). In addition, high expression of HDGF protein was positively correlated with T classification(p < 0.001), N classification (p < 0.001), and clinical stage (p < 0.001) of HCC patients. Patients with higher HDGF expression showed a significantly shorter overall survival time than did patients with low HDGF expression. Multivariate analysis suggested that HDGF expression might be an independent prognostic indicator(p < 0.001) for the survival of patients with HCC. HDGF-specific shRNA (shHDGF) successfully knocked down its endogenous expression in HepG2 cells. Compared to the parental and control shRNA-transfected (shCtrl) HepG2 cells, the shHDGF cells exhibited significantly reduced in vitro cell growth, anchorage-independent growth, cell migration and invasion (p < 0.05). In vivo, the xenograft transplants from shHDGF cells gave rise to much smaller tumors as compared to those from shCtrl cells.

CONCLUSION

High HDGF expression is associated with poor overall survival in patients with HCC. Down-regulation of HDGF inhibits the growth, anchorage-independent growth, migration and invasion of HepG2 cells.

Significance of HDGF expression in hepatocellular carcinoma tissue and HepG2 cells

AIM: To investigate the expression of hepatoma-derived growth factor (HDGF) in hepatocellular carcinoma (HCC) tissue and HepG2 cells and to analyze its significance.

METHODS: Ten HCC tissue samples and matched noncancerous tissue samples were collected. The mRNA expression of HDGF in these HCC samples, noncancerous tissue samples and HepG2 cells was detected by real-time RT-PCR. The protein expression of HDGF in 137 HCC tissue samples and 49 normal liver tissue samples was examined by immunohistochemistry. The relationship between HDGF expression and clinicopathological parameters in HCC was then analyzed.

RESULTS: The expression levels of HDGF mRNA were 21.11 and 11.39 times higher in HCC tissue and HepG2 cells than in noncancerous tissue, respectively. The positive rate of HDGF expression in HCC tissue was significantly higher than that in normal liver tissue (77.4% vs 51.5%, P = 0.011). High expression of HDGF protein was positively correlated with T classification, N classification and clinical stage (all P < 0.05) in HCC patients. Univariate Cox analysis showed that HDGF expression, N classification and clinical stage had significant correlation with survival prognosis of HCC patients (P = 0.028, 0.041 and 0.000; HR = 1.557, 1.526 and 2.316, respectively). Multivariate analysis showed that HDGF expression might be an independent prognostic indicator (P = 0.000, HR = 0.358) for the development and progression of HCC. Patients with higher HDGF expression showed a significantly shorter overall survival time than those with low HDGF expression.

CONCLUSION: HDGF is highly expressed in HCC tissue and HepG2 cells. High HDGF expression is an independent prognostic factor in HCC patients. High HDGF expression is associated with poor overall survival in patients with HCC.

Partial blockage of hepatocyte maturation in hepatoma-derived growth factor transgenic mice

AIM

To investigate the role of hepatoma-derived growth factor (HDGF) in liver development, especially in the hepatocyte differentiation.

METHODS

We generated transgenic mice which overexpressed HDGF in hepatocytes under the transcriptional control of mouse albumin promoter/enhancer. To examine the effects of HDGF overexpression on hepatocyte differentiation, we investigated the expression patterns of the differentiation marker genes.

RESULTS

The HDGF transgenic mice developed normally and showed no apparent abnormality in the liver. However, the gene expression patterns of the liver in adult transgenic mice were similar to those of the neonatal liver in control mice.

CONCLUSION

These findings suggest that HDGF-overexpression partially suppresses hepatocyte maturation.

Hepatoma-derived growth factor is induced in liver regeneration

AIM

Hepatoma-derived growth factor (HDGF) is a heparin-binding protein, which has been suggested to be involved in the development of kidneys, the cardiovascular system and the liver. We have shown that HDGF is highly expressed in parenchymal hepatocytes in the developing liver and promotes fetal hepatocyte proliferation. In the present study, we asked whether HDGF expression was related to liver regeneration.

METHODS

We examined the mRNA and protein expressions of HDGF in two liver regeneration models. In addition, cellular distribution of HDGF in the regenerating liver was investigated by immunohistochemistry.

RESULTS

In the carbon tetrachloride (CCl(4))-treated liver, HDGF expression was induced and the peak was detected at 24 h after the CCl(4 )injection. HDGF expression was also enhanced in the hepatectomy model and the peak was detected at 12 h after surgery. The increased expression of HDGF protein was also confirmed by western blotting. Expression of the HDGF gene in the regenerating liver was dominantly detected in parenchymal hepatocytes.

CONCLUSION

These findings showed that HDGF expression was induced in parenchymal hepatocytes before the DNA synthesis in the regenerating liver, suggesting the possible involvement of HDGF in liver regeneration as an autocrine factor.

Involvement of hepatoma-derived growth factor in the growth inhibition of hepatocellular carcinoma cells by vitamin K(2)

BACKGROUND

Vitamin K(2) has been reported to suppress the growth of human hepatocellular carcinoma (HCC) in vitro and hepatocarcinogenesis in hepatitis C virus (HCV)-related cirrhosis in vivo. Hepatoma-derived growth factor (HDGF) is a unique nuclear targeting growth factor that is highly expressed in HCC cells and is a possible prognostic factor for patients with HCC. We investigated the regulation of HDGF expression by vitamin K(2).

METHODS

Three HCC-derived cell lines, HepG2, HuH-7, and SK-Hep-1, were used. Cell number was determined with the MTT assay. The expression levels of HDGF mRNA and protein were measured by the real-time reverse transcriptase-polymerase chain reaction (PCR) method and ELISA and Western blot analysis, respectively. The HDGF promoter activity was measured by a dual luciferase-reporter assay.

RESULTS

Vitamin K(2) suppressed the growth of the three HCC cell lines in a dose-dependent manner. Vitamin K(2) significantly suppressed the expression of the HDGF protein and mRNA in three cell lines. By a luciferase assay, vitamin K(2) significantly suppressed the promoter activity of the HDGF protein. Based on some luciferase-reporter plasmids containing truncated promoter regions, the possible responsive site of vitamin K(2) seems to reside in the region -1 to -150 bp of the HDGF gene.

CONCLUSIONS

These findings suggested that regulation of the HDGF gene expression is one of the crucial mechanisms of vitamin K(2)-induced cell growth suppression for HCC.

Hepatoma-derived growth factor and its role in keloid pathogenesis

Hepatoma-derived growth factor (HDGF) is a novel mitogenic growth factor that has been implicated in many different carcinomas. Its role in keloid biology has not yet been investigated. The present study is aimed at examining the role of HDGF in keloid pathogenesis. Immunohistochemical staining and Western blot analyses were used to examine in vivo localization and expression of HDGF in keloid and normal skin tissue. This was followed by the detection of HDGF expression in fibroblasts cultured in vitro and fibroblasts exposed to serum. To investigate the effect of epithelial–mesenchymal interactions, a two-chamber system was employed in which keratinocytes on membrane inserts were co-cultured with the fibroblasts. HDGF expression levels in all cell extracts and conditioned media were assayed through Western blot analysis. In another set of experiments, the effect of exogenous recombinant HDGF on keloid fibroblasts (KF) and normal fibroblasts (NF) was examined. Cell proliferation was assessed by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and by quantifying proliferating cell nuclear antigen (PCNA) expression. Downstream targets of HDGF were identified by detecting their expression through Western blot analysis. Our results indicate that there was an increase in HDGF expression in the dermis of keloid compared with normal skin tissue. The application of serum and epithelial–mesenchymal interactions did not seem to have any effect on intracellular HDGF expression levels. However, co-culturing keloid keratinocytes with KFs resulted in increased HDGF secretion when compared with monoculture or normal controls. Furthermore, treatment with exogenous recombinant HDGF was found to increase the proliferation of KFs, activate the extracellular signal-regulated kinase (ERK) pathway and up-regulate the secretion of vascular endothelial growth factor (VEGF).

Downregulation of hepatoma-derived growth factor activates the Bad-mediated apoptotic pathway in human cancer cells

Hepatoma-derived growth factor (HDGF) is highly expressed in human cancer and its expression is correlated with poor prognosis of cancer. The growth factor is known to stimulate cell growth while the underlying mechanism is however not clear. Transfection with HDGF cDNA stimulated while its specific antisense oligonucleotides repressed the growth of human hepatocellular carcinoma HepG2 cells. Furthermore, knock-down of HDGF by antisense oligos also induced apoptosis in HepG2 cells and in other human cancer cells, e.g. human squamous carcinoma A431 cells. HDGF knock-down was found to induce the expression of the pro-apoptotic protein Bad and also inactivate ERK and Akt, which in turn led to dephosphorylation of Bad at Ser-112, Ser-136, and activation of the intrinsic apoptotic pathway, i.e. depolarization of the mitochondrial membrane, release of mitochondrial cytochrome c, increase in the processing of caspase 9 and 3. As HDGF knock-down not only suppresses the growth but also induces apoptosis in human cancer cells, HDGF may therefore serve as a survival factor for human cancer cells and a potential target for cancer therapy.

h-Prune is an independent prognostic marker for survival in esophageal squamous cell carcinoma

BACKGROUND

The human homologue of Drosophila prune (PRUNE, which encodes h-prune) protein interacts with glycogen synthase kinase 3 and promotes cell motility. The aim of our study was to investigate the impact of immunohistochemically detected h-prune expression on the survival of patients with esophageal squamous cell carcinoma (ESCC).

METHODS

Immunohistochemical staining of h-prune was performed for 205 surgically resected specimens of ESCC.

RESULTS

In total, 43 (21%) of 205 ESCC cases were positive for h-prune. h-prune-positive ESCC cases showed a more-advanced T stage (P < 0.0001), N stage (P < 0.0001), and tumor stage (P < 0.0001) than h-prune-negative ESCC cases. In the group of 116 stage II and III ESCC cases, recurrence of ESCC was frequently found in h-prune-positive cases. In patients with lung recurrence, the tumors were more likely to be h-prune positive than h-prune negative. Univariate analysis revealed that T stage (P < 0.0001), N stage (P < 0.0001), tumor stage (P < 0.0001), and h-prune staining (P < 0.0001) were significant prognostic factors for survival. Multivariate analysis indicated that N stage (P = 0.0182) and h-prune staining (P < 0.0001) were independent predictors for survival.

CONCLUSIONS

These results indicate that immunostaining of h-prune is useful to identify patients at high risk for recurrence or poor prognosis associated with ESCC.