Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Our recent published studies suggest that angiotensin II (AII), generated and retained intracellularly, enhances growth of H4-II-E-C3 rat hepatoma cells, an average of 33%. Proliferation conferred by introduction of a plasmid [ Ang(-S)Exp/pSVL ] encoding a signal sequence-depleted angiotensinogen [Ang(-S)Exp] into these cells (which we have shown possess ACE and renin mRNAs) is mediated, at least in part, by enhanced PDGF-A chain mRNA production and protein secretion. The mitogenic effect is inhibited by losartan suggesting that it involves AII interaction with an AT(1)-like receptor. Introduction of anti-AII antibodies into the medium of these transfected cells has no effect upon growth of the cells, suggesting that AII is retained by the cells and that intracellular AII is growth stimulatory. In the present study, we sought to further characterize the intracellular localization and mode of action of Ang(-S)Exp. Consistent with our expectations, we now show that a fusion product of Ang(-S)Exp with green fluorescent protein [Ang(-S)Exp/EGFP], generated from an expression plasmid, is abundant and primarily cytoplasmic. Wild-type angiotensinogen/EGFP, in contrast, is only detectable following a cold-block (which acts to enhance folding-kinetics and slow secretion) and is largely restricted to the secretory pathway. We further show, using semi-quantitative RT/PCR that the long isoform of PDGF mRNA is elevated in Ang(-S)Exp transfected cells and in AII-treated naive cells but not in losartan-treated Ang(-S)Exp transfected cells. We identify C-terminal amidation recognition sites within the long-form protein (that are not present in the short-form) and show that these cells possess PAM (amidating enzyme precursor) and carboxypeptidase E mRNAs (the corresponding proteins of which are sufficient for amidation). Inhibitors of amidation inhibit growth of naive and Ang(-S)Cntr/ pSVL -transfected cells (2.6-fold for phenylbutenoic acid and 3.5-fold for disulfiram treatment) but more profoundly inhibit growth of Ang(-S)Exp/pSVL -transfected cells (6.7-fold for phenylbutenoic acid and 13-fold for disulfiram). In conclusion, these data confirm that signal sequence-depleted Ang(-S)Exp is retained within cells and is largely cytoplasmic. Because C-terminal amidation is absolutely required for full biological potency of a number of peptide hormones (including oxytocin, gastrin and calcitonin), we postulate that growth effects of both intracellular AII and exogenous AII can be conferred by PDGF long-form, possibly through an amidation-dependent mechanism.
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PMID:Intracellular angiotensin II increases the long isoform of PDGF mRNA in rat hepatoma cells. 1243 51

Overexpression of platelet-derived growth factor A-chain (PDGF-A) is clearly linked to autocrine and paracrine stimulation of malignant growth in many human cancers. We have shown previously that PDGF-A overexpression in choriocarcinoma, hepatoma and lung carcinoma cell lines is driven by the activity of a 66 bp enhancer element (ACE66) located approximately 7 kb upstream of the PDGF-A transcription start site. In this study, the ACE66 element is shown to be activated in JEG-3 choriocarcinoma cells through synergistic interactions between consensus DNA motifs for binding of vitamin D receptor, AP1 and ELK1. Binding of the vitamin D/retinoid-X receptor (VDR/RXRalpha) heterodimer to the ACE66 element was reconstituted in vitro with recombinant VDR/RXRalpha and with JEG-3 nuclear extract, and was verified in living JEG-3 cells by chromatin immunoprecipitation analysis. Transcriptional activity of the ACE66 element, as well as occupancy of the element by VDR/RXRalpha, was shown to be independent of stimulation with the hormonal VDR ligand, 1,25-dihydroxyvitamin D3. The jun kinase pathway of mitogen-activated protein kinase (MAPK) signaling was shown to activate the ACE66 enhancer, most likely through activation of factors binding to the AP1 element. These results identify a novel mechanism of transcriptional enhancement involving ligand-independent activity of the VDR/RXR heterodimer and MAPK signaling pathways that appears to play an important role in the overexpression of PDGF in many different settings of human malignancy.
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PMID:A 5'-distal enhanceosome in the PDGF-A gene is activated in choriocarcinoma cells via ligand-independent binding of vitamin D receptor and constitutive jun kinase signaling. 1582 77

To gain insight into pathogenic mechanisms underlying fibrosis in hepatitis C virus (HCV)-mediated liver injury, we compared intrahepatic gene expression profiles in HCV-infected patients at different stages of fibrosis and alpha-smooth muscle actin (alpha-SMA) staining patterns. We studied 21 liver biopsy specimens: 5 had no fibrosis (Ludwig-Batts stage 0); 10 had early portal or periportal fibrosis (stages 1 and 2); and 6, advanced fibrosis (stages 3 and 4). None of the patients had hepatocellular carcinoma. Transcriptional profiles were determined by high-density oligonucleotide microarrays. ANOVA identified 157 genes for which transcript abundance was associated with fibrosis stage. These defined three distinct hierarchical clusters of patients. Patients with predominantly stage 0 fibrosis had increased abundance of mRNAs linked to glycolipid metabolism. PDGF, a potent stellate cell mitogen, was also increased. Transcripts with increased abundance in stages 1 and 2 fibrosis were associated with oxidative stress, apoptosis, inflammation, proliferation, and matrix degradation, whereas transcripts increased in stages 3 and 4 were associated with fibrogenesis and cellular proliferation. Cells staining for alpha-SMA were detectable at all stages but infrequent in advanced fibrosis without active inflammation. A high frequency of such cells was associated with mRNAs linked to glycolipid metabolism. In conclusion, the presence of alpha-SMA-positive HSCs and expression of PDGF in stage 0 fibrosis suggests that stellate cells are activated early in HCV-mediated injury, possibly in response to oxidative stress resulting from inflammation and lipid metabolism. Increased abundance of transcripts linked to cellular proliferation in advanced fibrosis is consistent with a predisposition to cancer. Supplementary material for this article can be found on the HEPATOLOGY website (http://www.interscience.wiley.com/jpages/0270-9139/suppmat/index/html).
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PMID:Intrahepatic gene expression profiles and alpha-smooth muscle actin patterns in hepatitis C virus induced fibrosis. 1598 78

This study assessed platelet activation and its possible contribution to the pathogenesis of liver cirrhosis (LC), hepatocellular carcinoma (HCC) and portal vein thrombosis (PVT). Forty-five patients with LC caused by dual schistosomiasis and viral hepatitis infections were enrolled in the study, 15 had LC only, 15 were complicated with HCC, and 15 were complicated with PVT, in addition to 15 healthy controls. Platelet morphological parameters including platelet count, platelet crit, mean platelet volume (MPV) and platelet distribution width (PDW), as well as platelet activation as evidenced by measuring soluble platelet selectin (sP-selectin) level and the release of beta-thromboglobulin (beta-TG), transforming growth factor beta-1 (TGF-beta1) and platelet derived growth factor-AA (PDGF-AA) were evaluated. The results obtained revealed significant reduction in platelet count, platelet crit and MPV while PDW was significantly increased in all LC patients in comparison to controls. sP-selectin, beta-TG, TGF-beta1 & PDGF-AA revealed significant increase in all diseased groups when compared to control group. Patients complicated with HCC or PVT demonstrated significant increase in the aforementioned parameters in comparison to patients with LC only. Patients with PVT showed significant increase versus HCC patients. These findings indicate that platelet activation is a prominent feature in LC and its serious complications HCC & PVT. This activation can play an important role in the pathogenesis of LC, HCC & PVT in patients with mixed schistosomiasis and viral hepatitis infections. Such patients need careful medical attention and effective treatment. Stabilization of the activated platelets and the dual suppression of PDGF & TGF-beta1 could be new therapeutic strategies against LC and its sequels.
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PMID:Assessment of platelet activation in coupled schistosomiasis and viral hepatitis infection: contribution to complexity of course and development of complications. 1715 99

Hepatocellular cancer (HCC) is a disease of poor prognosis. Identifying novel molecular aberrations might present opportunities to identify new therapeutic targets. Due to the similarities between the processes of development and cancer, we used early developing livers to identify genes that might play a primary role in HCC. Platelet-derived growth factor receptor-alpha (PDGFRalpha) was identified from microarray using early developing mouse livers. Expression of PDGFRalpha and its upstream effectors, PDGF-AA and PDGF-CC, were examined in HCC tissues (n = 43) by Western blot, real-time PCR, and immunohistochemistry. Finally, effect of anti-PDGFRalpha antibody (mAb 3G3, ImClone Systems, Inc.) was examined on human hepatoma cells. A high expression of PDGFRalpha was observed during early liver development. HCCs (17 of 21) revealed cytoplasmic PDGFRalpha and activated PDGFRalpha (phospho-Tyr(754)) by immunohistochemistry. Additional HCCs (14 of 22) showed elevated PDGFRalpha levels when compared with the adjacent normal livers by Western blots. Of these 14 patients, 3 showed increased PDGFRalpha gene expression, 3 showed elevated PDGF-AA, and 4 had higher PDGF-CC levels in the tumors compared with adjacent livers. Multiple hepatoma cell lines, when treated with mAb 3G3, showed significant decreases in cell proliferation and survival (P < 0.05). In conclusion, approximately 70% of HCC tissues had elevated PDGFRalpha levels due to diverse mechanisms. PDGFRalpha inhibition in hepatoma cells led to diminution of tumor cell survival and proliferation and thus might be of therapeutic significance.
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PMID:Platelet-derived growth factor receptor-alpha: a novel therapeutic target in human hepatocellular cancer. 1760 34

Non-invasive therapies for the treatment of hepatocellular carcinoma (HCC) would be of great benefit to public health. To this end, we have developed a platelet-derived growth factor-C (PDGF-C) transgenic (Tg) mouse model, which mimics many aspects of human liver carcinogenesis. Specifically, overexpression of PDGF-C results in liver fibrosis, which is preceded by activation and proliferation of hepatic stellate cells, and is followed by the development of dysplastic lesions and angiogenesis, and progression to HCCs by 8 months of age. Here, we show that PDGF-C overexpression induces the proliferation of endothelial-like cells that are present in tumors and adjacent non-neoplastic parenchyma. The protein tyrosine kinase inhibitor, imatinib (Gleevec), decreases the proliferation of non-parenchymal cells (NPC) in vitro and in vivo, with concomitant inhibition of Akt. In vivo treatment with imatinib also blocks the expression of CD34 in PDGF-C Tg mice. Decreased NPC proliferation and CD34 expression correlated with lower levels of active ERK1/2 and total levels of PDGF receptor alpha (PDGFRalpha). In summary, the small molecule inhibitor imatinib attenuates stromal cell proliferation in PDGF-C-induced HCC, which coincides with decreased expression of both CD34 and PDGFRalpha, and activated Akt. Our findings suggest that imatinib may be efficacious in the treatment of hepatocarcinogenesis, particularly when neovascularization is present.
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PMID:Targeting stromal cells for the treatment of platelet-derived growth factor C-induced hepatocellular carcinogenesis. 1799 42

Sunitinib malate is an oral, multitargeted receptor tyrosine kinase inhibitor of VEGF receptors 1, 2 and 3; PDGF receptors alpha and beta, and other receptor tyrosine kinases implicated in tumor growth, angiogenesis and metastasis. Hepatocellular carcinoma (HCC) is a highly vascular tumor that overexpresses several angiogenic factors; VEGF and PDGF signaling pathways play a key role in HCC. Until recently, treatment options for advanced HCC were limited and conventional therapies have met with poor response rates. Sorafenib provided proof-of-concept for molecularly targeted therapy in advanced HCC and has recently been approved for treatment. However, not all patients can tolerate sorafenib and patients may experience tumor progression; therefore, additional treatment options are warranted. Sunitinib has shown early evidence of anti-tumor activity in Phase II trials in US, European and Asian patients with locally advanced, unresectable and metastatic HCC. A Phase III trial of sunitinib in HCC is ongoing.
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PMID:Early development of sunitinib in hepatocellular carcinoma. 1910 14

Angiogenesis is essential for normal tissue and even more so for solid malignancies. At present, inhibition of tumor angiogenesis is a major focus of anticancer drug development. Bevacizumab, a humanized antibody against VEGF, was the first antiangiogenic agent to be approved for advanced non-small cell lung cancer, breast cancer and colorectal cancer. The most commonly observed adverse events are hypertension, proteinuria, bleeding and thrombosis. Sunitinib, a small molecule blocking intracellular VEGF, KIT, Flt3 and PDGF receptors, which regulate angiogenesis and cell growth, is approved for the treatment of advanced renal cell cancer (RCC) and malignant gastrointestinal stromal tumor. The most frequent adverse events include hand-foot syndrome, stomatitis, diarrhea, fatigue, hypothyroidism and hypertension. Sorafenib, an oral multikinase inhibitor, is approved for the second-line treatment of advanced RCC and upfront treatment of advanced hepatocellular carcinoma. Most common adverse events with sorafenib are dermatologic (hand-foot skin reaction, rash, desquamation), fatigue, diarrhea, nausea, hypothyroidism and hypertension. More recently, cardiovascular toxicity has increasingly been recognized as a potential adverse event associated with sunitinib and sorafenib treatment. Elderly patients are at increased risk of thromboembolic events when receiving bevacizumab, and potentially for cardiac dysfunction when receiving sunitinib or sorafenib. The safety of antiangiogenic drugs is of special concern when taking these agents for longer-term adjuvant or maintenance treatment. Furthermore, newer investigational antiangiogenic drugs are briefly reviewed.
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PMID:Antiangiogenic drugs in oncology: a focus on drug safety and the elderly - a mini-review. 1994 Apr 66

Sorafenib, a molecular-targeted agent that inhibits tumor cell proliferation and angiogenesis by inhibiting RAF serine-threonine kinase and VEGF, PDGF, Flt-3, c-Kit receptor tyrosine kinase, was approved in Europe and North America in 2007 and in Japan on May 20, 2009. In the 10 months since its approval, sorafenib has been prescribed for more than 3,700 patients with advanced hepatocellular carcinoma (HCC), and its efficacy has been confirmed in many cases. According to the consensus statements of the Japan Society of Hepatology in 2010, sorafenib is recommended for advanced HCC with extrahepatic spread or major vascular invasion such as invasion of the 1st branch of the portal vein or the main portal branch of the portal vein in patients with Child-Pugh A liver function. In addition to that, transcatheter arterial chemoembolization (TACE) or hepatic arterial infusion chemotherapy (HAIC) refractory HCC patients with Child-Pugh A liver function are also candidates of sorafenib monotherapy as a second-line treatment option. To date, 15 cases with complete remission (CR) to sorafenib in metastatic advanced HCC patients have been reported in Japan, an event that is rarely reported in other countries. Of the 90 cases treated by ourselves, 2 achieved CR. Factors indicating systemic cancer spread, including multiple liver lesions, lymph node metastases, adrenal metastases, lung metastases and vascular invasion, were completely absent in both cases of CR by 2 and 1 year, respectively. Similarly, three tumor markers (AFP, PIVKA-II, and AFP-L3) completely returned to normal values. Although cases of CR are rare, it seems that there might be racial differences in terms of gene mutations. Clinical trials for other molecular-targeted agents, including sunitinib, brivanib, or linifanib, are ongoing and their outcomes are eagerly awaited. According to a subanalysis of the SHARP study, it is expected that sorafenib in combination with resection, ablation, TACE or HAIC will markedly prolong the overall survival in early-, intermediate- and advanced- stage HCCs.
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PMID:Positioning of a molecular-targeted agent, sorafenib, in the treatment algorithm for hepatocellular carcinoma and implication of many complete remission cases in Japan. 2061 99

Liver injury causes vascular disorganization and local tissue hypoxia starting early in disease course. In this context, hypoxia acts not only as an aggravating factor of cell damage and inflammation, but also as an inhibitor of liver regeneration, a major stimulus of angiogenesis and fibrogenesis, and a promoter of liver carcinogenesis. Many of the effects of hypoxia are mediated by hypoxia-inducible factor-1alpha (HIF-1alpha), an oxygen-sensitive transcription factor. Compared to cells in the periportal area, intralobular hepatic stellate cells (HSCs) are more responsive to hypoxia and like other pericytes play a key role in angiogenesis through interactions with endothelial cells VIA platelet-derived growth factor (PGDF) and vascular endothelial growth factor (VEGF) signaling, at the leading edge of fibrotic septa. Although required for successful liver repair, angiogenesis in cirrhosis may be inefficient because of the immaturity and permeability of VEGF-induced neo-vessels, and thereby may fail to correct liver hypoxia. The multiple receptor tyrosine kinase inhibitors, acting on VEGF and PDGF receptors, initially designed for cancer treatment, show in addition to therapeutic efficacy in patients with hepatocellular carcinoma, beneficial effects on many aspects of the progression of liver diseases, including, fibrosis, inflammation and portal hypertension.
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PMID:Hypoxia: a link between fibrogenesis, angiogenesis, and carcinogenesis in liver disease. 2066 78


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