Serum and correspondent tissue measurements of epidermal growth factor (EGF) and epidermal growth factor receptor (EGF-R). Clinical relevance in pancreatic cancer and chronic pancreatitis

Modeling epithelial homeostasis and perturbation in three-dimensional human esophageal organoids

Background

Esophageal organoids from a variety of pathologies including cancer are grown in Advanced Dulbecco's Modified Eagle Medium-Nutrient Mixture F12 (hereafter ADF). However, the currently available ADF-based formulations are suboptimal for normal human esophageal organoids, limiting the ability to compare normal esophageal organoids with those representing a given disease state.

Methods

We have utilized immortalized normal human esophageal epithelial cell (keratinocyte) lines EPC1 and EPC2 and endoscopic normal esophageal biopsies to generate three-dimensional (3D) organoids. To optimize ADF-based medium, we evaluated the requirement of exogenous epidermal growth factor (EGF) and inhibition of transforming growth factor-(TGF)-β receptor-mediated signaling, both key regulators of proliferation of human esophageal keratinocytes. We have modeled human esophageal epithelial pathology by stimulating esophageal 3D organoids with interleukin (IL)-13, an inflammatory cytokine, or UAB30, a novel pharmacological activator of retinoic acid signaling.

Results

The formation of normal human esophageal 3D organoids was limited by excessive EGF and intrinsic TGFβ receptor-mediated signaling. In optimized HOME0, normal human esophageal organoid formation was improved, whereas IL-13 and UAB30 induced epithelial changes reminiscent of basal cell hyperplasia, a common histopathologic feature in broad esophageal disease conditions including eosinophilic esophagitis. Conclusions: HOME0 allows modeling of the homeostatic differentiation gradient and perturbation of the human esophageal epithelium while permitting a comparison of organoids from mice and other organs grown in ADF-based media.

Visualizing cellular heterogeneity by quantifying the dynamics of MAPK activity in live mammalian cells with synthetic fluorescent biosensors

Mitogen-Activated Protein Kinases (MAPKs) control a wide array of cellular functions by transducing extracellular information into defined biological responses. In order to understand how these pathways are regulated, dynamic single cell measurements are highly needed. Fluorescence microscopy is well suited to perform these measurements. However, more dynamic and sensitive biosensors that allow the quantification of signaling activity in living mammalian cells are required. We have engineered a synthetic fluorescent substrate for human MAPKs (ERK, JNK and p38) that relocates from the nucleus to the cytoplasm when phosphorylated by the kinases. We demonstrate that this reporter displays an improved response compared to other relocation biosensors. This assay allows to monitor the heterogeneity in the MAPK response in a population of isogenic cells, revealing pulses of ERK activity upon a physiological EGFR stimulation. We show applicability of this approach to the analysis of multiple cancer cell lines and primary cells as well as its application in vivo to developing tumors. Using this ERK biosensor, dynamic single cell measurements with high temporal resolution can be obtained. These MAPK reporters can be widely applied to the analysis of molecular mechanisms of MAPK signaling in healthy and diseased state, in cell culture assays or in vivo.

The emerging role of EGFL6 in angiogenesis and tumor progression

Epidermal growth factor-like domain-containing protein 6 (EGFL6) belongs to the epidermal growth factor (EGF) superfamily. EGFL6 is expressed at higher levels in embryos and various malignant tumors than in normal tissues. Recent studies suggest that EGFL6 participates in the development of a variety of tumors. In this review, we summarize findings that support the role for EGFL6 in tumor proliferation, invasion and migration. Furthermore, our review results indicate the mechanism of EGFL6 activity angiogenesis. We also describe work toward the preparation of monoclonal antibodies against EGFL6. Altogether, the work of this review promotes understanding of the role of EGFL6 in tumor development, the mechanism of that action, and the potential of EGFL6 as a therapeutic target for tumor prevention and treatment.

Erlotinib

The epidermal growth factor receptor (EGFR) has been implicated in a multiplicity of cancer-related signal transduction pathways like cellular proliferation, adhesion, migration, neoangiogenesis and apoptosis inhibition, all of which are important features of cancerogenesis and tumour progression. Its tyrosine kinase activity plays a central role in mediating these processes and has been intensely studied to exploit it as a therapeutic target. Inhibitors of this pathway have been developed and assessed in trials with significant efficacy in clinical applications. The current review focuses in particular on the clinical data of EGFR tyrosine kinase inhibition in different tumour entities, preferably non-small cell lung cancer and pancreatic cancer with emphasis to the approved small molecule erlotinib. Its clinical applications, evidence-based efficacy and toxicity as well as predictive markers of response are discussed.

Quantitative investigation of MDA-MB-231 breast cancer cell motility: dependence on epidermal growth factor concentration and its gradient

Enhanced cell motility is one of the primary features of cancer. Accumulated evidence demonstrates that Epidermal Growth Factor Receptor (EGFR) mediated pathways play an important role in breast cancer cell proliferation and migration. We have quantified the MDA-MB-231 breast cancer cell migration in response to the stimulation of EGFR pathways with their ligand EGF to determine how the cell motility of MDA-MB-231 cells depends on the ligand concentration and gradient. Analysis at the single cell level combined with mathematical modeling and the ability to vary the ligand concentration and gradients locally using microfluidic devices allowed us to separate the unique contributions of ligand concentration and ligand gradient to cell motility. We tracked the motility of 6600 cells individually using time lapse imaging under varying EGF stimulation conditions. Trajectory analysis of the tracked cells using non-linear multivariate regression models showed that: (i) cell migration of MDA-MB-231 breast cancer cells depends on the ligand gradient but not on the ligand concentration. This observation was valid for both the total (direction independent) and directed (along gradient direction) cell velocities. Although the dependence of the directed motility on ligand gradient is to be expected, the dependence of the total velocity solely on ligand gradient was an unexpected novel observation. (ii) Enhancement of the motilities of individual cells in a population upon exposure to the ligand was highly heterogeneous, and only a very small percentage of cells responded strongly to the external stimuli. Separating out the non-responding cells using quantitative analysis of individual cell motilities enabled us to establish that enhanced motility of the responding cells indeed increases monotonically with increasing EGF gradient. (iii) A large proportion of cells in a population were unresponsive to ligand stimulation, and their presence introduced considerable random intrinsic variability to the observations. This indicated that studying cell motilities at the individual cell level is necessary to better capture the biological reality and that population averaging methods should be avoided. Studying motilities at the individual cell level is particularly important to understand the biological processes that are possibly driven by the action of a small portion of cells in a population, such as metastasis. We discuss the implications of our results on the total and chemotactic movement of cancer cells in the tumor microenvironment.

High Level of Plasma EGFL6 Is Associated with Clinicopathological Characteristics in Patients with Oral Squamous Cell Carcinoma

EGF-like domain 6 (EGFL6), a member of the epidermal growth factor (EGF) repeat protein superfamily, is a secreted protein that promotes endothelial cell migration and angiogenesis. The current study investigated the association between the clinicopathological characteristics and plasma level of EGFL6 in patients with oral squamous cell carcinoma (OSCC). We measured the plasma EGFL6 levels of 392 OSCC patients by using a commercial enzyme-linked immunosorbent assay. We also analyzed EGFL6 mRNA levels of 328 OSCC patients from The Cancer Genome Atlas (TCGA) dataset. The results showed that plasma EGFL6 levels were significantly higher in patients with OSCC than in healthy controls (p < 0.001). Similar results were observed for the TCGA bioinformatics database. Moreover, plasma EGFL6 levels were significantly higher in the patients with advanced T status (p = 0.002), distant metastasis (p = 0.001), and higher TNM stage (p=0.033). In conclusion, our results suggest that plasma level of EGFL6 may be useful to assess disease progression, and especially advanced T status and higher TNM stage in patients with OSCC.

Tl(I) and Tl(III) alter the expression of EGF-dependent signals and cyclins required for pheochromocytoma (PC12) cell-cycle resumption and progression

The effects of thallium [Tl(I) and Tl(III)] on the PC12 cell cycle were evaluated without (EGF(-)) or with (EGF(+)) media supplementation with epidermal growth factor (EGF). The following markers of cell-cycle phases were analyzed: cyclin D1 (G1 ); E2F-1, cyclin E and cytosolic p21 (G1 →S transition); nuclear PCNA and cyclin A (S); and cyclin B1 (G2). The amount of cells in each phase and the activation of the signaling cascade triggered by EGF were also analyzed. Tl(I) and Tl(III) (5-100 μM) caused dissimilar effects on PC12 cell proliferation. In EGF(-) cells, Tl(I) increased the expression of G1 →S transition markers and nuclear PCNA, without affecting cyclin A or cyclin B1. In addition to those, cyclin B1 was also increased in EGF(+) cells. In EGF(-) cells, Tl(III) increased the expression of cyclin D1, all the G1→S and S phase markers and cyclin B1. In EGF(+) cells, Tl(III) increased cyclin D1 expression and decreased all the markers of G1 →S transition and the S phase. Even when these cations did not induce the activation of EGF receptor (EGFR) in EGF(-) cells, they promoted the phosphorylation of ERK1/2 and Akt. In the presence of EGF, the cations anticipated EGFR phosphorylation without affecting the kinetics of EGF-dependent ERK1/2 and Akt phosphorylation. Altogether, results indicate that Tl(I) promoted cell proliferation in both EGF(-) and EGF(+) cells. In contrast, Tl(III) promoted the proliferation of EGF(-) cells but delayed it in EGF(+) cells, which may be related to the toxic effects of this cation in PC12 cells.

Physiological epidermal growth factor concentrations activate high affinity receptors to elicit calcium oscillations

Signaling mediated by the epidermal growth factor (EGF) is crucial in tissue development, homeostasis and tumorigenesis. EGF is mitogenic at picomolar concentrations and is known to bind its receptor on high affinity binding sites depending of the oligomerization state of the receptor (monomer or dimer). In spite of these observations, the cellular response induced by EGF has been mainly characterized for nanomolar concentrations of the growth factor, and a clear definition of the cellular response to circulating (picomolar) concentrations is still lacking. We investigated Ca2+ signaling, an early event in EGF responses, in response to picomolar doses in COS-7 cells where the monomer/dimer equilibrium is unaltered by the synthesis of exogenous EGFR. Using the fluo5F Ca2+ indicator, we found that picomolar concentrations of EGF induced in 50% of the cells a robust oscillatory Ca2+ signal quantitatively similar to the Ca2+ signal induced by nanomolar concentrations. However, responses to nanomolar and picomolar concentrations differed in their underlying mechanisms as the picomolar EGF response involved essentially plasma membrane Ca2+ channels that are not activated by internal Ca2+ store depletion, while the nanomolar EGF response involved internal Ca2+ release. Moreover, while the picomolar EGF response was modulated by charybdotoxin-sensitive K+ channels, the nanomolar response was insensitive to the blockade of these ion channels.

Erlotinib

The epidermal growth factor receptor (EGFR) has been implicated in a multiplicity of cancer-related signal transduction pathways such as cellular proliferation, adhesion, migration, neoangiogenesis and apoptosis inhibition, all of them are important features of cancerogenesis and tumour progression. Its tyrosine kinase activity plays a central role in mediating these processes and has been intensely studied to exploit it as a therapeutic target. Inhibitors of this pathway have been developed and assessed in trials with significant efficacy in clinical applications. The current review focuses in particular on the clinical data of EGFR tyrosine kinase inhibition in different tumour entities, preferably non-small cell lung cancer and pancreatic cancer with emphasis to the approved small molecule erlotinib. Its clinical applications, evidence-based efficacy and toxicity as well as predictive markers of response are discussed.

Treatment options for advanced pancreatic cancer: a review

Advanced pancreatic adenocarcinoma historically has a poor prognosis and the mortality rate has remained unchanged for over a decade. Common treatment options for patients with advanced pancreatic cancer include chemoradiation and/or chemotherapy. Single-agent gemcitabine has been considered the standard of care since 1997. Recently published findings indicate that the oxaliplatin, irinotecan, fluorouracil and leucovorin (FOLFIRINOX) treatment regimen significantly improves overall survival compared with gemcitabine. Research has shifted to focus on understanding the causes the resistance of pancreatic cancer to chemotherapy and potential methods to overcome it. This review will focus on the current treatment options, the evolution of targeted therapy, novel agents on the horizon and potential options to ameliorate chemoresistance.

A phase II randomized study of cetuximab and bevacizumab alone or in combination with gemcitabine as first-line therapy for metastatic pancreatic adenocarcinoma

The purpose of this study was to assess the efficacy and safety of bevacizumab plus cetuximab with or without gemcitabine in patients with advanced pancreatic adenocarcinoma. Patients with locally advanced or metastatic pancreatic adenocarcinoma, previously untreated, were randomized to bevacizumab (10 mg/kg q2w) plus cetuximab (400/250 mg/m(2) initial/weekly), either with (Arm A) or without (Arm B) gemcitabine (1000 mg/m(2) weekly × 3 of 4 weeks). Tumor assessments were performed q8w. Primary study endpoint was progression-free survival (PFS). Sixty-one patients were randomized to Arm A (n = 30) or Arm B (n = 31). Median treatment duration was 9 weeks in Arm A and 8 weeks in Arm B (range, 2.0-40.4). Patients in Arm A had median PFS and overall survival values of 3.55 months and 5.41 months, respectively, compared to 1.91 months and 4.17 months in Arm B. The study closed early due to lack of sufficient efficacy in both treatment arms. Although both regimens were well tolerated, patients treated with gemcitabine experienced more grade 3-4 toxicities, including proteinuria and thromboembolic events. The combination of cetuximab and bevacizumab did not result in promising activity with or without gemcitabine, suggesting that a strategy of dual EGFR/VEGF inhibition in pancreatic cancer does not warrant further development. To our knowledge, this is one of the first trials to evaluate a completely noncytotoxic regimen in the first-line treatment of advanced pancreatic cancer. (ClinicalTrials.gov number, NCT00326911).

Erlotinib

The epidermal growth factor receptor (EGFR) has been implicated in a multiplicity of cancer-related signal transduction pathways like cellular proliferation, adhesion, migration, neoangiogenesis, and apoptosis inhibition, all of them important features of cancerogenesis and tumour progression. Its tyrosine kinase activity plays a central role in mediating these processes and has been intensely studied to exploit it as a therapeutic target. Inhibitors of this pathway have been developed and assessed in trials with significant efficacy in clinical applications. The current review focuses in particular on the clinical data of EGFR tyrosine kinase inhibition in different tumour entities, preferably non-small cell lung cancer (NSCLC) and pancreatic cancer with emphasis on the approved small molecule erlotinib. Its clinical applications, evidence-based efficacy, and toxicity as well as predictive markers of response are discussed.

New directions in the management of advanced pancreatic cancer: a review

Complete surgical resection is the only potentially curative option for pancreatic cancer. However, most patients have advanced/metastatic disease at the time of diagnosis, or will relapse after surgery. Systemic chemotherapy is only palliative. Gemcitabine-based therapy is an acceptable standard for unresectable locally advanced/metastatic pancreatic cancer, but average median survival is only 6 months. The addition of other chemotherapies (including other antimetabolites, platinum, and topoisomerase I inhibitors) or targeted therapies (farnesyl transferase inhibitors, metalloproteinase inhibitors, cetuximab and bevacizumab) to gemcitabine has failed to improve outcome. The combination of gemcitabine and erlotinib, a small-molecule tyrosine kinase inhibitor of the human epidermal growth factor receptor, was recently approved by the US/European authorities for use in advanced disease. In a phase III trial, the combination demonstrated a significant improvement in overall survival compared with gemcitabine monotherapy. Positive efficacy results have also been observed in a phase III trial, favoring the addition of capecitabine to gemcitabine compared with gemcitabine alone. This review focuses on the recent developments in systemic treatment, and discusses how novel agents might be incorporated into future treatment strategies for pancreatic cancer.

New therapeutic directions for advanced pancreatic cancer: targeting the epidermal growth factor and vascular endothelial growth factor pathways

In advanced pancreatic cancer, single-agent gemcitabine became the standard therapy approximately 10 years ago. Subsequently, combinations of gemcitabine with fluorouracil, cisplatin, irinotecan, oxaliplatin, or pemetrexed produced no clear survival benefit. Among the newer approaches, targeting human epidermal growth factor receptor (HER-1/EGFR) shows promise. The U.S. Food and Drug Administration recently approved erlotinib (a HER-1/EGFR tyrosine kinase inhibitor) combined with gemcitabine for the first-line treatment of advanced pancreatic cancer. This combination showed a statistically significant survival benefit over gemcitabine alone in locally advanced or metastatic disease (the median overall survival time was 6.24 months versus 5.91 months; hazard ratio, 0.82; p = .038); however, the clinical significance of this survival difference has been questioned. Additionally, a large phase III trial where the addition of cetuximab (an anti-HER-1/EGFR monoclonal antibody [mAb]) to gemcitabine failed to result in a longer overall survival time than with gemcitabine alone has been reported. Targeting vascular endothelial growth factor (VEGF) with bevacizumab (a recombinant, humanized IgG1 mAb that binds to VEGF) in combination with gemcitabine was investigated in a phase II trial, with promising outcomes that were unfortunately not supported by a subsequent phase III study. While the future treatment of pancreatic cancer may be influenced by the potential of certain biomarkers to predict better response to molecular-targeted therapies, allowing individualization of patient therapy, there are currently no clear candidates, and this remains an interesting area for further investigation.

Multiplexed Proximity Ligation Assays to Profile Putative Plasma Biomarkers Relevant to Pancreatic and Ovarian Cancer

Background: Sensitive methods are needed for biomarker discovery and validation. We tested one promising technology, multiplex proximity ligation assay (PLA), in a pilot study profiling plasma biomarkers in pancreatic and ovarian cancer.

Methods: We used 4 panels of 6- and 7-plex PLAs to detect biomarkers, with each assay consuming 1 μL plasma and using either matched monoclonal antibody pairs or single batches of polyclonal antibody. Protein analytes were converted to unique DNA amplicons by proximity ligation and subsequently detected by quantitative PCR. We profiled 18 pancreatic cancer cases and 19 controls and 19 ovarian cancer cases and 20 controls for the following proteins: a disintegrin and metalloprotease 8, CA-125, CA 19-9, carboxypeptidase A1, carcinoembryonic antigen, connective tissue growth factor, epidermal growth factor receptor, epithelial cell adhesion molecule, Her2, galectin-1, insulin-like growth factor 2, interleukin-1α, interleukin-7, mesothelin, macrophage migration inhibitory factor, osteopontin, secretory leukocyte peptidase inhibitor, tumor necrosis factor α, vascular endothelial growth factor, and chitinase 3–like 1. Probes for CA-125 were present in 3 of the multiplex panels. We measured plasma concentrations of the CA-125–mesothelin complex by use of a triple-specific PLA with 2 ligation events among 3 probes.

Results: The assays displayed consistent measurements of CA-125 independent of which other markers were simultaneously detected and showed good correlation with Luminex data. In comparison to literature reports, we achieved expected results for other putative markers.

Conclusion:

Multiplex PLA using either matched monoclonal antibodies or single batches of polyclonal antibody should prove useful for identifying and validating sets of putative disease biomarkers and finding multimarker panels.

Novel therapeutic approaches in the treatment of advanced pancreatic carcinoma

Pancreatic cancer is still a malignant disease of grim prognosis despite all therapeutic efforts. Because clinical symptoms in the early stage are usually absent or aspecific, it is frequently discovered at advanced or metastatic stage, only around 15-20% of tumors are resectable. In the majority of patients only the chemotherapy offers a prolongation of life, but even the first-line chemotherapeutic agent, the gemcitabine has a modest survival benefit, and objective tumor response is rarely achieved. Combination of various cytostatics did not produce a significant improvement either. For that reason, continuous search for other agents is mandatory. Nowadays, in the era of molecular-targeted oncotherapeutic approaches, pancreatic cancer is also a subject such trials: epidermal growth factor receptor blockade, inhibition of angiogenesis, modulation of tumor response through the extracellular matrix, inhibition of cyclooxygenase-2, farnesyl transferase inhibitors, signal transduction inhibitors, ablation of the hormonal influence and some other aspects have all been studies, but to date, no breakthrough in the treatment of pancreatic carcinoma is proven. In several Phase II-III studies these compounds given alone displayed marginal effects, but when combined with the standard cytostatics, some beneficial effects were observed, however, some of them displayed a severe (sometimes fatal) toxicity. To date, the role of the molecular targeted therapy in pancreatic carcinoma is promising, but the results are not convincingly superior to the standard chemotherapeutic treatments. Pancreatic adenocarcinoma remains a great challenge for the oncologists, and continuous search for better molecules and/or combinations is inevitable.

Growth factors in pancreatic health and disease

In this article the role of different growth factors and their receptors in the pathogenesis of chronic pancreatitis and pancreatic cancer is discussed. The expression of members of the epidermal growth factor family, the fibroblast growth factor family, the transforming growth factor-beta family, the platelet-derived growth factor family, the nerve growth factor family, the insulin-like growth factor family and their signaling receptors is presented, and a correlation of the molecular data with clinical and pathological changes is performed. A number of these growth factors and their receptors are markedly overexpressed in chronic pancreatitis and pancreatic cancer. In chronic pancreatitis, overexpression of growth factors and their receptors contributes to tissue remodeling and fibrogenesis. In contrast to chronic pancreatitis, pancreatic cancer is associated with a variety of genetic alterations, including mutations in tumor suppressor genes and cell cycle regulators. In the presence of these genetic disturbances, enhanced expression of growth factors and their receptors contributes to cell proliferation and enhances the aggressiveness of pancreatic cancer cells. In summary, growth factors and their receptors are often altered in chronic pancreatitis and pancreatic cancer and contribute to various pathogenetic aspects in these disorders.

Cloning, mapping, and expression analysis of a gene encoding a novel mammalian EGF-related protein (SCUBE1)

The epidermal growth factor (EGF) superfamily comprises a diverse group of proteins that function as secreted signaling molecules, growth factors, and components of the extracellular matrix, many with a role in vertebrate development. We have isolated a novel mammalian gene encoding an EGF-related protein with a CUB (C1s-like) domain that defines a new mammalian gene family. The Scube1 (signal peptide-CUB domain-EGF-related 1) gene was isolated from a developing mouse urogenital ridge cDNA library and is expressed prominently in the developing gonad, nervous system, somites, surface ectoderm, and limb buds. We have mapped Scube1 to mouse chromosome 15 and show that it is orthologous to a human gene in the syntenic region of chromosome 22q13. We discuss the possible functions of this novel gene and its role in heritable disease in light of these data.

Cloning of a novel epidermal growth factor repeat containing gene EGFL6: expressed in tumor and fetal tissues

The epidermal growth factor (EGF) repeat superfamily of genes often encodes proteins that govern cellular proliferative responses. Using a high-throughput screening by hybridization approach, a novel human EGF repeat superfamily member that maps to human chromosome X was identified. Termed EGFL6, the gene encodes a predicted signal peptide, suggesting that it is secreted. Other predicted features include four and one-half EGF-like repeat domains, two N-linked glycosylation sites, an integrin association motif (RGD), and a tyrosine phosphorylation site. Importantly, its transcripts are expressed in brain and lung tumor and fetal tissues, but are generally absent from normal adult tissues. Implications with respect to cell cycle regulation and oncogenesis are discussed.