TGFA; transforming growth factor, alpha (2p13)

Gene Summary

Gene:TGFA; transforming growth factor, alpha
Aliases: TFGA
Summary:This gene encodes a growth factor that is a ligand for the epidermal growth factor receptor, which activates a signaling pathway for cell proliferation, differentiation and development. This protein may act as either a transmembrane-bound ligand or a soluble ligand. This gene has been associated with many types of cancers, and it may also be involved in some cases of cleft lip/palate. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Sep 2011]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:protransforming growth factor alpha
Updated:14 December, 2014


What does this gene/protein do?
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Cancer Overview

Research Indicators

Publications Per Year (1989-2014)
Graph generated 14 December 2014 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 14 December, 2014 using data from PubMed, MeSH and CancerIndex

Notable (7)

Scope includes mutations and abnormal protein expression.

Entity Topic PubMed Papers
Breast CancerTGFA and Breast Cancer View Publications69
Colorectal CancerTGFA and Colonic Neoplasms View Publications56
Liver CancerTGFA and Liver Cancer View Publications42
Bladder CancerTGFA and Bladder Cancer View Publications10
NeuroblastomaTGFA Expression in Neuroblastoma View Publications8
Cervical CancerTGFA and Cervical Cancer View Publications7
Vulvar CancerTGFA and Vulvar Cancer View Publications3

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Related Links

Latest Publications: TGFA (cancer-related)

Moody TW, Chan DC, Mantey SA, et al.
SR48692 inhibits non-small cell lung cancer proliferation in an EGF receptor-dependent manner.
Life Sci. 2014; 100(1):25-34 [PubMed] Article available free on PMC after 28/03/2015 Related Publications
AIMS: The mechanism by which SR48692 inhibits non-small cell lung cancer (NSCLC) proliferation was investigated.
MAIN METHODS: The ability of SR48692 to inhibit the proliferation of NSCLC cell lines NCI-H1299 and A549 was investigated in vitro in the presence or absence of neurotensin (NTS). The ability of NTS to cause epidermal growth factor receptor (EGFR) transactivation was investigated by Western blot using NSCLC cells and various inhibitors. The growth effects and Western blot results were determined in cell lines treated with siRNA for NTSR1.
KEY FINDINGS: Treatment of A549 or NCI-H1299 cells with siRNA for NTSR1 reduced significantly NTSR1 protein and the ability of SR48692 to inhibit the proliferation of A549 or NCI-H1299 NSCLC cells. Treatment of A549 and NCI-H1299 cells with siRNA for NTSR1 reduced the ability of NTS to cause epidermal growth factor receptor (EGFR) transactivation. SR48692 or gefitinib (EGFR tyrosine kinase inhibitor) inhibited the ability of NTS to cause EGFR and ERK tyrosine phosphorylation. NTS transactivation of the EGFR was inhibited by GM6001 (matrix metalloprotease inhibitor), Tiron (superoxide scavenger) or U73122 (phospholipase C inhibitor) but not H89 (PKA inhibitor). NTS stimulates whereas SR48692 or gefitinib inhibits the clonal growth of NSCLC cells.
SIGNIFICANCE: These results suggest that SR48692 may inhibit NSCLC proliferation in an EGFR-dependent mechanism.

Related: Non-Small Cell Lung Cancer Lung Cancer EGFR Gefitinib (Iressa)

Zhao D, Zhai B, He C, et al.
Upregulation of HIF-2α induced by sorafenib contributes to the resistance by activating the TGF-α/EGFR pathway in hepatocellular carcinoma cells.
Cell Signal. 2014; 26(5):1030-9 [PubMed] Related Publications
Sorafenib, the first-line systemic drug for advanced hepatocellular carcinoma (HCC), has demonstrated limited benefits with very low response rates. Thus it is essential to investigate the underlying mechanisms for the resistance to sorafenib and seek potential strategy to enhance its efficacy. Hypoxic cells inside solid tumors are extremely resistant to therapies as their survival ability is increased due to the cellular adaptive response to hypoxia, which is controlled by hypoxia-inducible factor (HIF)-1 and HIF-2. Sorafenib inhibits HIF-1α synthesis, making the hypoxic response switch from HIF-1α- to HIF-2α-dependent pathways and providing a mechanism for more aggressive growth of tumors. The present study has demonstrated that upregulation of HIF-2α induced by sorafenib contributes to the resistance of hypoxic HCC cells by activating the transforming growth factor (TGF)-α/epidermal growth factor receptor (EGFR) pathway. Blocking the TGF-α/EGFR pathway by gefitinib, a specific EGFR inhibitor, reduced the activation of STAT (signal transducer and activator of transcription) 3, AKT and ERK (extracellular signal-regulated kinase), and synergized with sorafenib to inhibit proliferation and induce apoptosis of hypoxic HCC cells. Transfection of HIF-2α siRNA into HCC cells downregulated the expression of VEGF (vascular endothelial growth factor), cyclin D1, HIF-2α and TGF-α, and inhibited the activation of EGFR. HIF-2α siRNA inhibited the proliferation and promoted the apoptosis of HCC cells in vitro, and synergized with sorafenib to suppress the growth of HCC tumors in vivo. The results indicate that targeting HIF-2α-mediated activation of the TGF-α/EGFR pathway warrants further investigation as a potential strategy to enhance the efficacy of sorafenib for treating HCC.

Related: Liver Cancer Signal Transduction Sorafenib (Nexavar) Gefitinib (Iressa)

Weiss J, Hayes DN
Classifying squamous cell carcinoma of the head and neck: prognosis, prediction and implications for therapy.
Expert Rev Anticancer Ther. 2014; 14(2):229-36 [PubMed] Related Publications
Traditionally, squamous cell cancers of the head and neck (SCCHN) have been classified by their anatomic location and stage. This system has been unsatisfactory in that it leaves substantial heterogeneity in prognosis and inadequate definition of optimal therapy. The most promising novel marker for superior prognosis in SCCHN is human papillomavirus (HPV). Overexpression of the EGFR bears an adverse prognosis; no marker provides clear predictive power for benefit from EGFR inhibition. Low expression of the DNA repair enzymes and excision repair cross-complementing rodent repair deficiency (ERCC1) and x-ray repair complementing defective repair in Chinese hamster cells 1 (XRCC1) may predict chemotherapy and chemoradiotherapy sensitivity. Tumors expressing cyclin D1 have a poor prognosis. Genomic characterization has subdivided SCCHN into four categories with clear biologic themes. Basal cancers express high levels of TGF-α and have other perturbations of the EGFR axis. Mesenchymal cancers show evidence for epithelial to mesenchymal transition. Atypical cancers lack both EGFR amplification and deletion of 9p; they also have a higher rate of HPV positivity than the other groups. Classical tumors demonstrate gene signatures similar to those previously associated with exposure to cigarette smoke; patients with this signature had a greater smoking history than patients in the other groups.

Related: Head and Neck Cancers Head and Neck Cancers - Molecular Biology

Nasrallah A, Saykali B, Al Dimassi S, et al.
Effect of StarD13 on colorectal cancer proliferation, motility and invasion.
Oncol Rep. 2014; 31(1):505-15 [PubMed] Related Publications
Colon cancer is a cancer of the epithelial cells lining the colon. It is mainly divided into different stages according to the invasiveness and metastatic ability of the tumor. Many mutations are acquired which leads to the development of this malignancy. These occur in entities that greatly affect the cell cycle, cell signaling pathways and cell motility, which all involve the action of Rho GTPases. The protein of interest in the present study was DLC2, also known as StarD13 or START-GAP2, a GTPase-activating protein (GAP) for Rho and Cdc42. Literature data indicate that this protein is considered a tumor-suppressor in hepatocellular carcinoma. Previous research in our laboratory confirmed StarD13 as a tumor suppressor in astrocytoma and in breast cancer. In the present study, we investigated the role of StarD13 in colon cancer. When overexpressed, StarD13 was found to lead to a decrease in cell proliferation in colon cancer cells. Consistently, knockdown of StarD13 led to an increase in cell proliferation. This showed that, similarly to its role in astrocytoma and breast cancer, StarD13 appears to be a tumor suppressor in colon cancer as well. We also examined the role of StarD13 in cell motility. StarD13 knockdown resulted in the inhibition of 2D cell motility. This was due to the inhibition of Rho; consequently Rac-dependent focal complexes were not formed nor detached for the cells to move forward. However, StarD13 knockdown led to an increase in 3D cell motility. Although StarD13 was indeed a tumor suppressor in our colon cancer cells, as evidenced by its effect on cell proliferation, it was required for cancer cell invasion. The present study further describes the role of StarD13 as a tumor suppressor as well as a Rho GAP.

Related: Colorectal (Bowel) Cancer Signal Transduction TGFB1 TP53 CDC42 RHOA

Wu J, Tong S, Zhan Z, et al.
TGF-α gene variations and increased susceptibility of gastric cancer in an Eastern Chinese Han population.
Biomarkers. 2014; 19(1):9-15 [PubMed] Related Publications
Transforming growth factor-alpha (TGF-α) correlates with deep invasion, advanced stage and poor prognosis in gastric cancer. Genetic variants in the 3' untranslated region (UTR) of TGF-α gene may influence the stability and post-transcriptional regulation of mRNA and contribute to gastric cancer predisposition. To test this hypothesis, we genotyped five polymorphisms in 3'UTR (rs3771527, rs503314, rs473698, rs3732253 and rs538118) and one in 3' near region (rs11466306) of the TGF-α gene by polymerase chain reaction-ligation detection reaction methods (PCR-LDR). We found that GA/AA genotype of rs11466306 in the 3' near gene could increase the risk of overall gastric cancer (adjusted OR = 1.499, 95%CI: 1.101-2.041), compared to the wild homozygous GG genotype. Meanwhile, the risk effect was more obvious in the intestinal gastric cancer and gastric noncardia cancer (adjusted OR = 1.682, 95%CI: 1.188-2.380; adjusted OR = 1.495, 95%CI: 1.072-2.086, respectively), but not for the diffuse type and gastric cardia cancer (p > 0.05). CT/TT genotype for rs3732253 in the 3' UTR was associated with increased risk of intestinal gastric cancer (adjusted OR = 1.464, 95%CI: 1.036-2.069), compared to their wild homozygous genotypes. These findings indicate that potentially functional TGF-α gene variant may contribute to the risk of intestinal gastric cancer and/or gastric noncardia cancer and could be used as molecular markers for detecting intestinal gastric cancer and/or gastric noncardia cancer in Chinese Han population.

Related: Stomach Cancer Gastric Cancer

Matsushima-Nishiwaki R, Kumada T, Nagasawa T, et al.
Direct association of heat shock protein 20 (HSPB6) with phosphoinositide 3-kinase (PI3K) in human hepatocellular carcinoma: regulation of the PI3K activity.
PLoS One. 2013; 8(11):e78440 [PubMed] Article available free on PMC after 28/03/2015 Related Publications
HSP20 (HSPB6), one of small heat shock proteins (HSPs), is constitutively expressed in various tissues and has several functions. We previously reported that the expression levels of HSP20 in human hepatocellular carcinoma (HCC) cells inversely correlated with the progression of HCC, and that HSP20 suppresses the growth of HCC cells via the AKT and mitogen-activated protein kinase signaling pathways. However, the exact mechanism underlying the effect of HSP20 on the regulation of these signaling pathways remains to be elucidated. To clarify the details of this effect in HCC, we explored the direct targets of HSP20 in HCC using human HCC-derived HuH7 cells with HSP20 overexpression. HSP20 proteins in the HuH7 cells were coimmunoprecipitated with the p85 regulatory subunit and p110 catalytic subunit of phosphoinositide 3-kinase (PI3K), an upstream kinase of AKT. Although HSP20 overexpression in HCC cells failed to affect the expression levels of PI3K, the activity of PI3K in the unstimulated cells and even in the transforming growth factor-α stimulated cells were downregulated by HSP20 overexpression. The association of HSP20 with PI3K was also observed in human HCC tissues in vivo. These findings strongly suggest that HSP20 directly associates with PI3K and suppresses its activity in HCC, resulting in the inhibition of the AKT pathway, and subsequently decreasing the growth of HCC.

Related: Liver Cancer AKT1 Signal Transduction

Gacche RN, Meshram RJ
Targeting tumor micro-environment for design and development of novel anti-angiogenic agents arresting tumor growth.
Prog Biophys Mol Biol. 2013; 113(2):333-54 [PubMed] Related Publications
Angiogenesis: a process of generation of new blood vessels has been proved to be necessary for sustained tumor growth and cancer progression. Inhibiting angiogenesis pathway has long been remained a significant hope for the development of novel, effective and target orientated antitumor agents arresting the tumor proliferation and metastasis. The process of neoangiogenesis as a biological process is regulated by several pro- and anti-angiogenic factors, especially vascular endothelial growth factor, fibroblast growth factor, epidermal growth factor, hypoxia inducible factor 1 and transforming growth factor. Every endothelial cell destined for vessel formation is equipped with receptors for these angiogenic peptides. Moreover, numerous other angiogenic cytokines such as platelet derived growth factor (PGDF), placenta growth factor (PGF), nerve growth factor (NGF), stem-cell factor (SCF), and interleukins-2, 4, 6 etc. These molecular players performs critical role in regulating the angiogenic switch. Couple of decade's research in molecular aspects of tumor biology has unraveled numerous structural and functional mysteries of these angiogenic peptides. In present article, a detailed update on the functional and structural peculiarities of the various angiogenic peptides is described focusing on structural opportunities made available that has potential to be used to modulate function of these angiogenic peptides in developing therapeutic agents targeting neoplastic angiogenesis. The data may be useful in the mainstream of developing novel anticancer agents targeting tumor angiogenesis. We also discuss major therapeutic agents that are currently used in angiogenesis associated therapies as well as those are subject of active research or are in clinical trials.

Related: Angiogenesis Inhibitors Cancer Prevention and Risk Reduction Angiogenesis and Cancer

Troiani T, Martinelli E, Napolitano S, et al.
Increased TGF-α as a mechanism of acquired resistance to the anti-EGFR inhibitor cetuximab through EGFR-MET interaction and activation of MET signaling in colon cancer cells.
Clin Cancer Res. 2013; 19(24):6751-65 [PubMed] Related Publications
PURPOSE: Although cetuximab, an anti-EGF receptor (EGFR) monoclonal antibody, is an effective treatment for patients with KRAS wild-type metastatic colorectal cancer (mCRC), its clinical use is limited by onset of resistance.
EXPERIMENTAL DESIGN: We characterized two colorectal cancer models to study the mechanisms of acquired resistance to cetuximab.
RESULTS: Following chronic treatment of nude mice bearing cetuximab-sensitive human GEO colon xenografts, cetuximab-resistant GEO (GEO-CR) cells were obtained. In GEO-CR cells, proliferation and survival signals were constitutively active despite EGFR inhibition by cetuximab treatment. Whole gene expression profiling identified a series of genes involved in the hepatocyte growth factor (HGF)-MET-dependent pathways, which were upregulated in GEO-CR cells. Furthermore, activated, phosphorylated MET was detected in GEO-CR cells. A second colorectal cancer cell line with acquired resistance to cetuximab was obtained (SW48-CR). Inhibition of MET expression by siRNA restored cetuximab sensitivity in GEO-CR and SW48-CR cells, whereas exogenous activation of MET by HGF stimulation in cetuximab-sensitive GEO and SW48 cells induced resistance to cetuximab. Treatment of GEO-CR and SW48-CR cells with PHA665752, a selective MET inhibitor, inhibited cell growth, proliferation, and survival signals and impaired cancer cell migration. Overexpression of TGF-α, a specific EGFR ligand, was involved in the acquisition of cetuximab resistance in GEO-CR and SW48-CR cells. In fact, TGF-α overexpression induced the EGFR-MET interaction, with subsequent MET phosphorylation and activation of MET downstream effectors in GEO-CR and SW48-CR cells.
CONCLUSIONS: These results suggest that overexpression of TGF-α through induction of EGFR-MET interaction contributes to cetuximab resistance in colorectal cancer cells. The combined inhibition of EGFR and MET receptor could represent a strategy for preventing and/or overcoming cetuximab resistance in patients with colorectal cancer.

Related: MET gene Signal Transduction EGFR Cetuximab (Erbitux)

Klotzsche-von Ameln A, Prade I, Grosser M, et al.
PHD4 stimulates tumor angiogenesis in osteosarcoma cells via TGF-α.
Mol Cancer Res. 2013; 11(11):1337-48 [PubMed] Related Publications
UNLABELLED: Solid tumor growth is intimately associated with angiogenesis, a process that is efficiently triggered by hypoxia. Therefore, oxygen-sensitive signaling pathways are thought to play a critical role in tumor angiogenesis and progression. Here, the function of prolyl hydroxylase-4 (PHD4), a relative of the prolyl hydroxylase domain proteins 1-3 that promote the degradation of hypoxia-inducible factors (HIF), was interrogated. To test the hypothesis that PHD4 might inhibit tumor angiogenesis, it was overexpressed in osteosarcoma cells, and unexpectedly, this manipulation led to increased tumor blood vessel density. However, the newly formed blood vessels were smaller than normal and appeared to be partially nonfunctional, as indicated by poor vessel perfusion. PHD4 overexpression in tumor cells stimulated the expression of TGF-α, which was necessary and sufficient to promote angiogenic sprouting of endothelial cells. On the other hand, PHD4 overexpression reduced HIF-2α protein levels, which in turn inhibited in vivo tumor growth. Combined, elevated PHD4 levels deregulate angiogenesis via increased TGF-α expression in vitro and in vivo. These data support the hypothesis that tumor growth can be uncoupled from vessel density and that the individual PHD family members exert distinct functions in tumors.
IMPLICATIONS: PHD4 influences tumor growth and vascularization through discrete mechanisms and molecular pathways that likely have therapeutic potential.

Related: Angiogenesis and Cancer Osteosarcoma Signal Transduction

Tian K, Rajendran R, Doddananjaiah M, et al.
Dynamics of DNA damage induced pathways to cancer.
PLoS One. 2013; 8(9):e72303 [PubMed] Article available free on PMC after 28/03/2015 Related Publications
Chemotherapy is commonly used in cancer treatments, however only 25% of cancers are responsive and a significant proportion develops resistance. The p53 tumour suppressor is crucial for cancer development and therapy, but has been less amenable to therapeutic applications due to the complexity of its action, reflected in 66,000 papers describing its function. Here we provide a systematic approach to integrate this information by constructing a large-scale logical model of the p53 interactome using extensive database and literature integration. The model contains 206 nodes representing genes or proteins, DNA damage input, apoptosis and cellular senescence outputs, connected by 738 logical interactions. Predictions from in silico knock-outs and steady state model analysis were validated using literature searches and in vitro based experiments. We identify an upregulation of Chk1, ATM and ATR pathways in p53 negative cells and 61 other predictions obtained by knockout tests mimicking mutations. The comparison of model simulations with microarray data demonstrated a significant rate of successful predictions ranging between 52% and 71% depending on the cancer type. Growth factors and receptors FGF2, IGF1R, PDGFRB and TGFA were identified as factors contributing selectively to the control of U2OS osteosarcoma and HCT116 colon cancer cell growth. In summary, we provide the proof of principle that this versatile and predictive model has vast potential for use in cancer treatment by identifying pathways in individual patients that contribute to tumour growth, defining a sub population of "high" responders and identification of shifts in pathways leading to chemotherapy resistance.

Related: Cancer Prevention and Risk Reduction Signal Transduction

Oue N, Naito Y, Hayashi T, et al.
Signal peptidase complex 18, encoded by SEC11A, contributes to progression via TGF-α secretion in gastric cancer.
Oncogene. 2014; 33(30):3918-26 [PubMed] Related Publications
We built an in-house oligonucleotide array on which 394 genes were selected based on our Serial Analysis of Gene Expression (SAGE) data and previously reported array data and listed several genes related to cancer progression. Among these, we focused on SEC11A, which encodes the SPC18 protein. SEC11A mRNA expression was measured by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) in gastric cancer (GC) tissue samples. Expression and distribution of SPC18 protein were investigated by immunohistochemical analysis in two independent GC cohorts (Hiroshima cohort, n=99 and Chiba cohort, n=989). To determine the effect of SPC18 on cell viability and invasiveness in vitro, MTT and Boyden chamber invasion assays were performed. To evaluate the influence of SPC18 on cell growth in vivo, GC cells were injected into severe combined immunodeficiency mice. Levels of TGF-α and EGF in media from the GC cells were measured by enzyme-linked immunosorbent assay (ELISA). Studies in human tissue revealed overexpression of SEC11A mRNA in 40% of 42 GC samples by qRT-PCR. Immunohistochemical analysis of SPC18 revealed that 26 and 20% of GC cases were SPC18-positive in the Hiroshima and Chiba cohorts, respectively. In both cohorts, the Kaplan-Meier analysis showed poorer survival in SPC18-positive GC cases than in SPC18-negative GC cases. Forced expression of SPC18 activates GC cell growth in vitro and in vivo. The levels of TGF-α in culture media from GC cells were reduced by knockdown of SPC18. These results indicate that SPC18 contributes to malignant progression through promotion of TGF-α secretion in GC.

Related: Stomach Cancer Gastric Cancer

Nickerson NK, Mill CP, Wu HJ, et al.
Autocrine-derived epidermal growth factor receptor ligands contribute to recruitment of tumor-associated macrophage and growth of basal breast cancer cells in vivo.
Oncol Res. 2013; 20(7):303-17 [PubMed] Article available free on PMC after 28/03/2015 Related Publications
Epidermal growth factor receptor (EGFR) expression has been linked to progression of basal breast cancers. Many breast cancer cells harbor the EGFR and produce its family of ligands, suggesting they may participate in autocrine and paracrine signaling with cells of the tumor microenvironment. EGFR ligand expression was profiled in the basal breast cancer cell line MDA-231 where AREG, TGF-alpha, and HBEGF were the three ligands most highly expressed. Autocrine signaling was modulated through silencing or overexpression of these three ligands using lentiviral constructs and the impact measured using motility, proliferation, and cytokine expression assays. Changes in receptor phosphorylation and receptor turnover were examined. Knockdown of AREG or TGF-alpha in vitro resulted in decreased motility (p < 0.05) and decreased expression of macrophage chemoattractants. Overexpression of TGF-alpha increased motility and chemoattractant expression, whereas AREG did not. HBEGF modulation had no effect on any cellular behaviors. All the cells with altered ligand production were inoculated into female athymic nude mice to form mammary fat pad tumors, followed by immunohistochemical analysis for necrosis, angiogenesis, and macrophage recruitment. In vivo, knockdown of AREG or TGF-alpha increased survival (p < 0.001) while decreasing angiogenesis (p < 0.001), tumor growth (p < 0.001), and macrophage attraction (p < 0.001). Overexpression of AREG appeared to elicit a greater effect than TGF-alpha on mammary fat pad tumor growth by increasing angiogenesis (p < 0.001) and macrophage attraction to the tumor (p < 0.01). We propose these changes in mammary tumor growth were the result of increased recruitment of macrophages to the tumor by cells with altered autocrine EGFR signaling. We conclude that AREG and TGF-alpha were somewhat interchangeable in their effects on EGFR signaling; however, TGF-alpha had a greater effect in vitro and AREG had a greater effect in vivo.

Related: Breast Cancer

Chang LH, Pan SL, Lai CY, et al.
Activated PAR-2 regulates pancreatic cancer progression through ILK/HIF-α-induced TGF-α expression and MEK/VEGF-A-mediated angiogenesis.
Am J Pathol. 2013; 183(2):566-75 [PubMed] Related Publications
Tissue factor initiates the process of thrombosis and activates cell signaling through protease-activated receptor-2 (PAR-2). The aim of this study was to investigate the pathological role of PAR-2 signaling in pancreatic cancer. We first demonstrated that activated PAR-2 up-regulated the protein expression of both hypoxia-inducible factor-1α (HIF-1α) and HIF-2α, resulting in enhanced transcription of transforming growth factor-α (TGF-α). Down-regulation of HIFs-α by siRNA or YC-1, an HIF inhibitor, resulted in depleted levels of TGF-α protein. Furthermore, PAR-2, through integrin-linked kinase (ILK) signaling, including the p-AKT, promoted HIF protein expression. Diminishing ILK by siRNA decreased the levels of PAR-2-induced p-AKT, HIFs-α, and TGF-α; our results suggest that ILK is involved in the PAR-2-mediated TGF-α via an HIF-α-dependent pathway. Furthermore, the culture medium from PAR-2-treated pancreatic cancer cells enhanced human umbilical vein endothelial cell proliferation and tube formation, which was blocked by the MEK inhibitor, PD98059. We also found that activated PAR-2 enhanced tumor angiogenesis through the release of vascular endothelial growth factor-A (VEGF-A) from cancer cells, independent of the ILK/HIFs-α pathways. Consistent with microarray analysis, activated PAR-2 induced TGF-A and VEGF-A gene expression. In conclusion, the activation of PAR-2 signaling induced human pancreatic cancer progression through the induction of TGF-α expression by ILK/HIFs-α, as well as through MEK/VEGF-A-mediated angiogenesis, and it plays a role in the interaction between cancer progression and cancer-related thrombosis.

Related: HIF1A Angiogenesis and Cancer Cancer of the Pancreas Pancreatic Cancer Signal Transduction VEGFA

Giricz O, Calvo V, Peterson EA, et al.
TACE-dependent TGFα shedding drives triple-negative breast cancer cell invasion.
Int J Cancer. 2013; 133(11):2587-95 [PubMed] Article available free on PMC after 28/03/2015 Related Publications
The epidermal growth factor receptor (EGFR) is frequently expressed in triple-negative breast cancer (TNBC) and is a marker of poor prognosis in this patient population. Because activating mutations in this kinase are very rare events in breast cancer, we screened breast tumor gene expression profiles to examine the distribution of EGFR ligand expression. Of the six known EGFR ligands, transforming growth factor alpha (TGFα) was expressed more highly in triple-negative breast tumors than in tumors of other subtypes. TGFα is synthesized as a transmembrane precursor requiring tumor necrosis factor alpha converting enzyme (TACE)/ADAM17-dependent proteolytic release to activate its receptor. In our study, we show that an inhibitor of this proteolytic release blocks invasion, migration and colony formation by several TNBC cell lines. Each of the effects of the drug was reversed upon expression of a soluble TGFα mutant that does not require TACE activity, implicating this growth factor as a key metalloproteinase substrate for these phenotypes. Together, these data demonstrate that TACE-dependent TGFα shedding is a key process driving EGFR activation and subsequent proliferation and invasion in TNBC cell lines.

Related: Breast Cancer Cancer Prevention and Risk Reduction Signal Transduction EGFR

Cabrijan L, Lipozencić J, Batinac T, et al.
Differences between keratoacanthoma and squamous cell carcinoma using TGF-alpha.
Coll Antropol. 2013; 37(1):147-50 [PubMed] Related Publications
Squamous cell carcinoma (SCC) and keratoacanthoma (KA) are skin neoplasms of epithelial origin. In contrast to clearly malignant skin neoplasm SCC, KA is an unusual cutaneous neoplasm with a tendency to regression. The distinction between these two neoplasms, on histological grounds only, is still a challenge. In order to investigate further and to assess the possible differences in transforming growth factor-alpha (TGF-alpha) expression between SCC and KA, 40 of skin tumor specimens, 20 cases of each SCC and KA were analyzed immunohystochemicaly. We have found a significant difference in staining patterns between KA and SCC. In KAs we have detected TGF-alpha staining mainly diffusely (90% of cases) and without peripheral staining of cells in 1-2 layers (60% of cases). Contrary, there was a mostly patchy staining (55% of cases) with peripheral staining of cells in 1-2 layers (100% of cases) in SCCs. Generally, differentiation between KA and SCC can be based on clinical and histological ground, but the distinction between these two skin tumors could sometimes be difficult. We have shown that these skin neoplasms could be differentiated based on staining patterns of TGF-alpha expression, thus this method could aid in differentiation between these two closely related entities in clinical practice.

Related: Skin Cancer

Xu Y, Tokar EJ, Person RJ, et al.
Recruitment of normal stem cells to an oncogenic phenotype by noncontiguous carcinogen-transformed epithelia depends on the transforming carcinogen.
Environ Health Perspect. 2013; 121(8):944-50 [PubMed] Article available free on PMC after 28/03/2015 Related Publications
BACKGROUND: Cancer stem cells (CSCs) drive tumor initiation, progression, and metastasis. The microenvironment is critical to the fate of CSCs. We have found that a normal stem cell (NSC) line from human prostate (WPE-stem) is recruited into CSC-like cells by nearby, but noncontiguous, arsenic-transformed isogenic malignant epithelial cells (MECs).
OBJECTIVE: It is unknown whether this recruitment of NSCs into CSCs by noncontact co-culture is specific to arsenic-transformed MECs. Thus, we used co-culture to examine the effects of neighboring noncontiguous cadmium-transformed MECs (Cd-MECs) and N-methyl-N-nitrosourea-transformed MECs (MNU-MECs) on NSCs.
RESULTS: After 2 weeks of noncontact Cd-MEC co-culture, NSCs showed elevated metalloproteinase-9 (MMP-9) and MMP-2 secretion, increased invasiveness, increased colony formation, decreased PTEN expression, and formation of aggressive, highly branched duct-like structures from single cells in Matrigel, all characteristics typical of cancer cells. These oncogenic characteristics did not occur in NSCs co-cultured with MNU-MECs. The NSCs co-cultured with Cd-MECs retained self-renewal capacity, as evidenced by multiple passages (> 3) of structures formed in Matrigel. Cd-MEC-co-cultured NSCs also showed molecular (increased VIM, SNAIL1, and TWIST1 expression; decreased E-CAD expression) and morphologic evidence of epithelial-to-mesenchymal transition typical for conversion to CSCs. Dysregulated expression of SC-renewal genes, including ABCG2, OCT-4, and WNT-3, also occurred in NSCs during oncogenic transformation induced by noncontact co-culture with Cd-MECs.
CONCLUSIONS: These data indicate that Cd-MECs can recruit nearby NSCs into a CSC-like phenotype, but MNU-MECs do not. Thus, the recruitment of NSCs into CSCs by nearby MECs is dependent on the carcinogen originally used to malignantly transform the MECs.

Related: Prostate Cancer

Gao MQ, Kim BG, Kang S, et al.
Human breast cancer-associated fibroblasts enhance cancer cell proliferation through increased TGF-α cleavage by ADAM17.
Cancer Lett. 2013; 336(1):240-6 [PubMed] Related Publications
We demonstrate here increased expression of ADAM17 protein in cancer-associated fibroblasts (CAFs) extracted from human breast carcinomas compared with donor-matched normal fibroblasts, and TGF-α secretion positively correlates with ADAM17 expression in these cells. In SK-BR-3 cells co-cultured with CAFs, CAF-secreted TGF-α promotes cell proliferation by activation of EGFR, Akt, and ERK, but it does not promote cell migration. Furthermore, anti-TGF-α neutralizing antibodies antagonize the CAF-dependent increase in proliferation and activation of EGFR, Akt and ERK. Thus, pharmacologic inhibition of ADAM17 and TGF-α may have therapeutic potential for the treatment of breast cancer when fibroblast-directed therapy is considered.

Related: Breast Cancer

Yang J, Zhang W
New molecular insights into osteosarcoma targeted therapy.
Curr Opin Oncol. 2013; 25(4):398-406 [PubMed] Related Publications
PURPOSE OF REVIEW: Recent translational studies in osteosarcoma are discussed with the purpose to shed light on the new molecular therapeutic targets.
RECENT FINDINGS: The genetic aberrations of vascular endothelial growth factor (VEGF), mammalian target of rapamycin, Wnt signaling pathway, the inactivation of p53, Rb, WWOX genes, and amplification of APEX1, c-myc, RECQL4, RPL8, MDM2, VEGFA might be involved in the pathogenesis of osteosarcoma. The promising therapeutic targets for osteosarcoma patients include: integrin, ezrin, statin, NOTCH/HES1, matrix metalloproteinases (MMPs), m-calpain, and Src, which are involved in tumor cell invasion and metastasis; aldolase A, fructose-bisphosphate, sulfotransferase family 3A, member 1, BCL2-associated athanogene 3, heat shock protein 70 (HSP70), B-cell lymphoma 2-interacting mediator (BIM), polo-like kinase 1, hypoxia inducible factor 1, alpha subunit, minibrain-related kinase, Bcl-xl, caspase-3, midkine, high mobility group box 1 protein (HMGB1), and Beclin1, which are involved in tumor proliferation and apoptosis; met proto-oncogene (hepatocyte growth factor receptor), v-erb-b2 erythroblastic leukemia viral oncogene homolog 2, insulin-like growth factor (IGF)-1R, fms-related tyrosine kinase 4, platelet-derived growth factor receptor, beta polypeptide, IGF-I/II, and c-kit, which are involved in tumor growth; endosialin, VEGF, thrombin, and MMPs, which are involved in tumor angiogenesis; transforming growth factor-α/β, parathyroid hormone-like hormone, interleukin-6, interleukin-11, receptor activator of nuclear factor-κB ligand, nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1, and cathepsin, which are involved in osteoclast function; Myc, HSP90, p-Met, p-Akt, p-STAT3, and cyclin D1, which are transcriptional factors; p-GP, hydroxysteroid (17-beta) dehydrogenase 10, HMGB1, BIM, inorganic phosphate, Bcl-2, PARP, mdm2, p21, Bax, and mitogen-activated protein kinase 1, which are involved in drug sensitivity. Furthermore, microRNAs such as miR-215 are also therapeutic targets.
SUMMARY: These translational studies in osteosarcoma have identified new molecular targets for osteosarcoma.

Related: Bone Cancers Osteosarcoma

Jin Y, Peng D, Shen Y, et al.
MicroRNA-376c inhibits cell proliferation and invasion in osteosarcoma by targeting to transforming growth factor-alpha.
DNA Cell Biol. 2013; 32(6):302-9 [PubMed] Related Publications
MicroRNAs are a class of small noncoding RNAs that function as critical gene regulators through targeting mRNAs for translational repression or degradation. In this study, we showed that miR-376c expression level was decreased while transforming growth factor-alpha (TGFA) mRNA expression levels were increased in osteosarcoma tissues and cell lines, and we identified TGFA as a novel direct target of miR-376c. Overexpression of miR-376c suppressed TGFA expression and the expression of its downstream signaling molecule such as epidermal growth factor receptor, and attenuated cell proliferation and invasion. Forced expression of TGFA could partly rescue the inhibitory effect of miR-376c in the cells. Taken together, these findings will shed light on the role and mechanism of miR-376c in regulating osteosarcoma cell growth via miR-376c/TGFA axis, and miR-376c may serve as a potential therapeutic target in osteosarcoma in the future.

Related: Bone Cancers Osteosarcoma

Llorente-Izquierdo C, Mayoral R, Cucarella C, et al.
Progression of liver oncogenesis in the double transgenic mice c-myc/TGF α is not enhanced by cyclooxygenase-2 expression.
Prostaglandins Other Lipid Mediat. 2013; 106:106-15 [PubMed] Related Publications
Cyclooxygenase-2 (COX-2) has been associated with cell growth regulation, tissue remodeling and carcinogenesis. Overexpression of COX-2 in hepatocytes constitutes an ideal condition to evaluate the role of prostaglandins (PGs) in liver pathogenesis. The effect of COX-2-dependent PGs in genetic hepatocarcinogenesis has been investigated in triple c-myc/transforming growth factor α (TGF-α) transgenic mice that express human COX-2 in hepatocytes on a B6CBAxCD1xB6DBA2 background. Analysis of the contribution of COX-2-dependent PGs to the development of hepatocarcinogenesis, evaluated in this model, suggested a minor role of COX-2-dependent prostaglandins to liver oncogenesis as indicated by liver histopathology, morphometric analysis and specific markers of tumor progression. This allows concluding that COX-2 is insufficient for modifying the hepatocarcinogenesis course mediated by c-myc/TGF-α.

Related: COX2 (PTGS2) Liver Cancer Signal Transduction

Kobayashi H, Kumagai K, Gotoh A, et al.
Upregulation of epidermal growth factor receptor 4 in oral leukoplakia.
Int J Oral Sci. 2013; 5(1):14-20 [PubMed] Article available free on PMC after 28/03/2015 Related Publications
In the present study, we investigate the expression profile of the epidermal growth factor receptor family, which comprises EGFR/ErbB1, HER2/ErbB2, HER3/ErbB3 and HER4/ErbB4 in oral leukoplakia (LP). The expression of four epidermal growth factor receptor (EGFR) family genes and their ligands were measured in LP tissues from 14 patients and compared with levels in 10 patients with oral lichen planus (OLP) and normal oral mucosa (NOM) from 14 healthy donors by real-time polymerase chain reaction (PCR) and immunohistochemistry. Synchronous mRNA coexpression of ErbB1, ErbB2, ErbB3 and ErbB4 was detected in LP lesions. Out of the receptors, only ErbB4 mRNA and protein was more highly expressed in LP compared with NOM tissues. These were strongly expressed by epithelial keratinocytes in LP lesions, as shown by immunohistochemistry. Regarding the ligands, the mRNA of Neuregulin2 and 4 were more highly expressed in OLP compared with NOM tissues. Therefore, enhanced ErbB4 on the keratinocytes and synchronous modulation of EGFR family genes may contribute to the pathogenesis and carcinogenesis of LP.

Related: ERBB3 ERBB4 (HER4)

Zhu C, Li J, Ding Q, et al.
miR-152 controls migration and invasive potential by targeting TGFα in prostate cancer cell lines.
Prostate. 2013; 73(10):1082-9 [PubMed] Related Publications
BACKGROUND: MicroRNAs (miRNAs) are a class of short non-coding RNAs that function in diverse biological processes. Aberrant miR-152 expression has been frequently reported in various malignant tumors. However, the mechanism of miR-152 in prostate cancer (PCa) remains unclear. This study aims to determine the function of miR-152 in PCa cells and identify the novel molecular targets regulated by miR-152.
METHODS: The expression levels of transforming growth factor-alpha (TGFα) were determined in three samples of PCa and adjacent non-tumorous tissues by Western blot analysis. miR-152 levels in 48 primary PCa and 15 non-malignant tissue samples were measured by qRT-PCR. The effects of forced miR-152 expression or TGFα knockdown on PCa cells were evaluated by cell migration and invasion assays, as well as Western blot analysis. Dual-luciferase reporter assay was used to identify binding sites between miR-152 and TGFα 3'-UTR.
RESULTS: TGFα was upregulated in PCa tissue samples compared with that in adjacent normal ones. miR-152 expression was significantly decreased in primary PCa samples compared with that in non-malignant samples. Patients with Gleason scores >7 exhibited lower miR-152 levels than those with lower scores. Moreover, low miR-152 expression is correlated with advanced pathological T-stages. Forced miR-152 expression or TGFα knockdown significantly reduced the migratory and invasive capabilities of PCa cells in vitro. TGFα is a direct target gene of miR-152.
CONCLUSIONS: Our findings suggest that miR-152 can act as a tumor suppressor that targets TGFα. miR-152 is a promising molecular target that inhibits PCa cell migration and invasion.

Related: Prostate Cancer

Nottingham LK, Yan CH, Yang X, et al.
Aberrant IKKα and IKKβ cooperatively activate NF-κB and induce EGFR/AP1 signaling to promote survival and migration of head and neck cancer.
Oncogene. 2014; 33(9):1135-47 [PubMed] Article available free on PMC after 28/03/2015 Related Publications
The inhibitor-κB kinase-nuclear factor-κB (IKK-NF-κB) and epidermal growth factor receptor-activator protein-1 (EGFR-AP1) pathways are often co-activated and promote malignant behavior, but the underlying basis for this relationship is unclear. Resistance to inhibitors of IKKβ or EGFR is observed in head and neck squamous cell carcinomas (HNSCC). Here, we reveal that both IKKα and β contribute to nuclear activation of canonical and alternate NF-κB/REL family transcription factors, and overexpression of signal components that enhance co-activation of the EGFR-AP1 pathway. We observed that IKKα and IKKβ exhibit increased protein expression, nuclear localization, and phosphorylation in HNSCC tissues and cell lines. Individually, IKK activity varied among different cell lines, but overexpression of both IKKs induced the strongest NF-κB activation. Conversely, siRNA knock down of both IKKs significantly decreased nuclear localization and phosphorylation of canonical RELA and IκBα and alternative p52 and RELB subunits. Knock down of both IKKs more effectively inhibited NF-κB activation, broadly modulated gene expression and suppressed cell proliferation and migration. Global expression profiling revealed that NF-κB, cytokine, inflammatory response and growth factor signaling are among the top pathways and networks regulated by IKKs. Importantly, IKKα and IKKβ together promoted the expression and activity of transforming growth factor α, EGFR and AP1 transcription factors cJun, JunB and Fra1. Knock down of AP1 subunits individually decreased 8/15 (53%) of IKK-targeted genes sampled and similarly inhibited cell proliferation and migration. Mutations of NF-κB and AP1-binding sites abolished or decreased IKK-induced interleukin-8 (IL-8) promoter activity. Compounds such as wedelactone with dual IKK inhibitory activity and geldanomycins that block IKKα/β and EGFR pathways were more active than IKKβ-specific inhibitors in suppressing NF-κB activation and proliferation and inducing cell death. We conclude that IKKα and IKKβ cooperatively activate NF-κB and EGFR/AP1 networks of signaling pathways and contribute to the malignant phenotype and the intrinsic or acquired therapeutic resistance of HNSCC.

Related: Head and Neck Cancers Head and Neck Cancers - Molecular Biology Signal Transduction EGFR

Shiraha H, Yamamoto K, Namba M
Human hepatocyte carcinogenesis (review).
Int J Oncol. 2013; 42(4):1133-8 [PubMed] Article available free on PMC after 28/03/2015 Related Publications
Hepatocellular carcinoma is the third most frequent cause of cancer-related death worldwide; and its incidence rate is increasing. Clinical and molecular medical analyses have revealed substantial information on hepatocarcinogenesis. Hepatocarcinogenesis is a stepwise process during which multiple genes are altered. Genetic changes and their biological consequences in human HCC can be divided into at least 4 groups: i) tumor suppressor genes (p53, retinoblastoma, phosphatase tensin homolog and runt-related transcription factor 3), ii) oncogenes (myc, K-ras, BRAF), iii) reactivation of developmental pathways (Wnt, hedgehog), and iv) growth factors and their receptors (transforming growth factor-α, insulin-like growth factor-2 receptor). An experimental model of human hepatocarcinogenesis such as in vitro neoplastic transformation of human hepatocytes has not been successfully achieved yet, but several immortalized human hepatocyte cell lines have been established. These immortalized human hepatocytes will become useful tools for the elucidation of hepatocarcinogenesis, especially for the initial step of multistep hepatocarcinogenesis.

Related: Liver Cancer

Yang D, Zhu Z, Wang W, et al.
Expression profiles analysis of pancreatic cancer.
Eur Rev Med Pharmacol Sci. 2013; 17(3):311-7 [PubMed] Related Publications
BACKGROUND: [Corrected] Pancreatic cancer is the fourth most common cause of cancer-related deaths across the globe and has a poor prognosis.
AIM: To investigate the characteristics of genomic expression profiles of pancreatic cancer and screen differentially expressed genes.
MATERIALS AND METHODS: Using GSE16515 dataset downloaded from GEO (Gene Expression Omnibus) database, we first screened the differentially expressed genes (DEGs) in pancreatic cancer by packages in R language. The key functions of DEGs were investigated by GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analysis. The potential functionally important SNP (Single Nucleotide Polymorphism) was selected from the dbSNP database.
RESULTS: A total of 1270 DEGs were identified. Most of them were predicted to be involved in pancreatic cancer development by sequence variant. Six genes (CDC42, STAT1, RALA, BCL2L1, TGFA, and EGF) were enriched in the known pancreatic cancer pathway. All these six genes had SNP, usually mutation at A/G and C/T point.
CONCLUSIONS: Our results provide some underlying biomarkers for early diagnosis of pancreatic cancer.

Related: Cancer Screening and Early Detection Cancer of the Pancreas Pancreatic Cancer

Byer SJ, Brossier NM, Peavler LT, et al.
Malignant peripheral nerve sheath tumor invasion requires aberrantly expressed EGF receptors and is variably enhanced by multiple EGF family ligands.
J Neuropathol Exp Neurol. 2013; 72(3):219-33 [PubMed] Article available free on PMC after 28/03/2015 Related Publications
Aberrant epidermal growth factor receptor (EGFR) expression promotes the pathogenesis of malignant peripheral nerve sheath tumors (MPNSTs), the most common malignancy associated with neurofibromatosis type 1, but the mechanisms by which EGFR expression promotes MPNST pathogenesis are poorly understood. We hypothesized that inappropriately expressed EGFRs promote MPNST invasion and found that these kinases are concentrated in MPNST invadopodia in vitro. Epidermal growth factor receptor knockdown inhibited the migration of unstimulated MPNST cells in vitro, and exogenous EGF further enhanced MPNST migration in a substrate-specific manner, promoting migration on laminin and, to a lesser extent, collagen. In this setting, EGF acts as a chemotactic factor. We also found that the 7 known EGFR ligands (EGF, betacellulin, epiregulin, heparin-binding EGF, transforming growth factor-α [TGF-α], amphiregulin, and epigen) variably enhanced MPNST migration in a concentration-dependent manner, with TGF-α being particularly potent. With the exception of epigen, these factors similarly promoted the migration of nonneoplastic Schwann cells. Although transcripts encoding all 7 EGFR ligands were detected in human MPNST cells and tumor tissues, only TGF-α was consistently overexpressed and was found to colocalize with EGFR in situ. These data indicate that constitutive EGFR activation, potentially driven by autocrine or paracrine TGF-α signaling, promotes the aggressive invasive behavior characteristic of MPNSTs.

Related: Signal Transduction

Pentheroudakis G, Kotoula V, De Roock W, et al.
Biomarkers of benefit from cetuximab-based therapy in metastatic colorectal cancer: interaction of EGFR ligand expression with RAS/RAF, PIK3CA genotypes.
BMC Cancer. 2013; 13:49 [PubMed] Article available free on PMC after 28/03/2015 Related Publications
BACKGROUND: More than half of patients with KRAS-wild type advanced colorectal cancer (CRC) fail anti-EGFR monoclonal antibodies. We studied EGFR-axis messenger RNA (mRNA) expression and RAS, RAF, PIK3CA mutations in order to identify additional biomarkers of cetuximab efficacy.
METHODS: Previously genotyped (KRAS, NRAS, BRAF, PIK3CA mutations) formalin-fixed paraffin-embedded tumour biopsies of 226 cetuximab-treated CRC patients (1st to 3rd line therapy) were assessed for mRNA expression of epidermal growth factor receptor (EGFR) and its ligands EGF, Transofrming Growth Factor-a (TGFA), Amphiregulin (AREG) and Epiregulin (EREG) with real time quantitative PCR. Mutations were detected in 72 (31.9%) tumours for KRAS, in 6 (2.65%) for BRAF, in 7 (3.1%) for NRAS and in 37 (16.4%) for PIK3CA.
RESULTS: Only PIK3CA mutations occasionally coexisted with other gene mutations. In univariate analysis, prognostic significance for survival ( from metastases until death) was seen for BRAF mutations (Hazard Ratio HR 8.1, 95% CI 3.4-19), codon 12-only KRAS mutations (HR 1.62, 95% CI 1.1-2.4), high AREG mRNA expression only in KRAS wild type CRC (HR 0.47, 95% CI 0.3-0.7) and high EREG mRNA expression irrespective of KRAS mutation status (HR 0.45, 95% CI 0.28-0.7). EREG tumoural mRNA expression was significantly associated with a 2.26-fold increased likelihood of objective response to cetuximab therapy (RECIST 1.1). In multivariate analysis, favourable predictive factors were high AREG mRNA in KRAS wild type tumours, high EREG mRNA, low Ephrin A2 receptor mRNA. Cetuximab-treated patients with AREG-low KRAS wild type CRC fared very poorly, their survival being similar to KRAS mutant CRC. Patients with KRAS codon 13 or other non-codon 12 mutations had a median survival (30 months, 95% CI 20-35) similar to that of patients with KRAS wild-type (median survival 29 months, 95% CI 25-35), in contrast to patients with KRAS codon 12 mutations who fared worse (median survival 19 months, 95% CI 15-26).
CONCLUSIONS: BRAF and codon 12 KRAS mutations predict for adverse outcome of CRC patients receiving cetuximab. AREG mRNA reflects EGFR signalling in KRAS wild type tumours, predicting for cetuximab efficacy when high and failure when low. EREG may have a prognostic role independent of KRAS mutation.

Related: BRAF gene EGFR Cetuximab (Erbitux)

Yang CH, Cho M
Hepatitis B virus X gene differentially modulates cell cycle progression and apoptotic protein expression in hepatocyte versus hepatoma cell lines.
J Viral Hepat. 2013; 20(1):50-8 [PubMed] Related Publications
The hepatitis B virus (HBV) X gene, which encodes the hepatitis B virus x protein (HBx), is essential for viral infection and genome replication, virus-associated liver disease, and development of hepatocellular carcinoma. However, the exact role(s) of HBx remain controversial. In this study, we focus on studying the role of HBx in the regulation of cell cycle and apoptosis in normal liver and hepatoma cell lines. We established the Huh7-X and Chang-X cell lines that constitutively express HBx. There were differences between the two cell lines in terms of cell cycle regulation and expression of p27 and transforming growth factor-β. Expression of HBx proteins dramatically increases expression of Bcl-2 and reduces levels of cleaved PARP protein in Chang-X cells, and it inhibits apoptosis under unfavourable conditions, such as serum starvation, in both cell lines. Our findings provide clues about the intracellular roles of HBx and demonstrate that expression of this protein is important for multiple cellular processes, that is, cell cycle progression and apoptosis, in hepatoma cells and normal liver cell lines.

Related: Apoptosis CDKN1B Liver Cancer Signal Transduction

Demirkan BH, Eriksson B
Systemic treatment of neuroendocrine tumors with hepatic metastases.
Turk J Gastroenterol. 2012; 23(5):427-37 [PubMed] Related Publications
Neuroendocrine tumors, 1-2% of all malignancies, are relatively slow-growing neoplasms. The majority of neuroendocrine tumors belong to the World Health Organization Group 2 with well-differentiated endocrine carcinomas, but some tumors can be aggressive. The most common are gastroenteropancreatic-neuroendocrine tumors, followed by bronchopulmonary neuroendocrine tumors; less frequent locations are the ovaries, testis and hepatobiliary locations. They can be either non-functioning tumors with symptoms related to mass effects and malignant tumor disease or functioning tumors with specific hormones/neuropeptides autonomously secreted to induce specific clinical syndromes. Localized neuroendocrine tumors are less frequent than metastatic ones; in fact, up to 75% of patients with small bowel neuroendocrine tumors and 30-85% of pancreatic neuroendocrine tumors present with liver metastases either at the time of diagnosis or during the course of the disease. The predominant metastatic site is the liver, which is the best prognostic marker of survival regardless of the primary site. If surgical resection or interventional therapies of the hepatic tumor burden are not feasible, or if the metastases are not confined to the liver, systemic treatment remains the only option. None of the systemic therapies is liver-specific, but rather acts on all metastatic sites. The lack of prospective studies comparing different treatment modalities in homogeneous cohorts of patients makes the best treatment strategy poorly defined. Standard systemic therapy options are somatostatin analogues (octreotide and lanreotide), interferon-α and chemotherapy. Somatostatin analogues not only control symptoms related to functioning tumors but tumor growth as well. Because of the studies challenging its efficacy, as well as the potential for side effects, the more widespread acceptance of interferon-α in the treatment of metastatic neuroendocrine tumors has been limited. Well-differentiated neuroendocrine tumors do not show high sensitivity to chemotherapy because of their low mitotic rates, high levels of antiapoptotic protein bcl-2 and increased expression of the multi-drug resistant gene. Traditional chemotherapeutic agents are streptozotocin in combination with 5-fluorouracil or doxorubicin, or to some extent dacarbazine. Temozolomide, capecitabine and oxaliplatin, as monoagents or in combination therapy, show efficacy in phase II trials. Patients with poorly differentiated neuroendocrine tumor, regardless of the primary tumor localization, are candidates for cisplatin and etoposide chemotherapy regimen. Peptide receptor radionuclide therapy is reported to be an effective treatment option for patients with good performance status and high somatostatin-receptor scintigraphy uptake as well as without major liver involvement. Basic fibroblast growth factor, vascular endothelial growth factor, platelet-derived growth factor, transforming growth factor alpha and beta, insulin-like growth factor type 1, epidermal growth factor, stem cell factor (c-kit), and corresponding receptors have been shown to be expressed in Neuroendocrine tumors. Current phase II-III clinical trials with molecular-targeted therapies revealed promising agents such as everolimus (RAD001), an oral mTOR inhibitor, and sunitinib malate (SU-11248), an oral multitargeted tyrosine kinase inhibitor against vascular endothelial growth factor receptors, platelet-derived growth factor receptors, c-kit receptors, glial cell linederived neurotrophic factor, and FMS-like tyrosine kinase-3 (Flt 3), which were approved for the treatment of advanced pancreatic neuroendocrine tumors. Ongoing clinical trials with bevacizumab, a humanized monoclonal antibody against vascular endothelial growth factor, will further define the role of angiogenesis inhibitors in advanced intestinal neuroendocrine tumors. Various further novel strategies of targeted therapy and microRNA-regulated pathways in neuroendocrine tumors are under development.

Related: Gastrointestinal System Cancers

Husain H, Psyrri A, Markovic A, et al.
Nuclear epidermal growth factor receptor and p16 expression in head and neck squamous cell carcinoma.
Laryngoscope. 2012; 122(12):2762-8 [PubMed] Article available free on PMC after 28/03/2015 Related Publications
OBJECTIVES/HYPOTHESIS: Epidermal growth factor receptor (EGFR) and p16 (a surrogate marker of human papillomavirus [HPV] infection) expression are strong prognostic factors in patients with head and neck squamous cell carcinoma (HNSCC).
STUDY DESIGN: We examined expression levels of total and nuclear EGFR as well as p16 status based on evidence that nuclear EGFR may have a role in DNA damage repair.
METHODS: An HPV-negative (SQ20B) and an HPV-positive (UMSCC47) HNSCC cell line were examined for EGFR and γH2AX expression. A tissue microarray containing 123 cores obtained from 101 HNSCC tumors was analyzed for EGFR expression by automated quantitative analysis and p16 expression by immunohistochemical staining, and these results were correlated with available clinical data.
RESULTS: SQ20B had higher EGFR expression than UMSCC47. Nuclear localization of EGFR on activation with transforming growth factor-α was observed in SQ20B, but not in UMSCC47. SQ20B also had increased γH2AX foci compared to UMSCC47, suggesting that SQ20B has more DNA damage compared to UMSCC47. Total and nuclear EGFR was reliably obtained from 80 of 101 patients. p16 levels were determined in 87 of 101 patients. p16 levels were strongly associated with the oropharyngeal subsite and poorly differentiated histology. Expression of total and nuclear EGFR was higher in p16-negative tumors compared to p16-positive tumors (Wilcoxon rank test, P = .038 and P = .014, respectively).
CONCLUSIONS: Further studies are required to determine a mechanistic link between these two prognostic factors and the significance of EGFR localization to nucleus in DNA damage repair pathway activation.

Related: Head and Neck Cancers Head and Neck Cancers - Molecular Biology


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