Relationship between activation of epidermal growth factor receptor and cell dissociation in pancreatic cancer.
ABSTRACT In our previous investigations, mitogen-activated protein kinase kinase 2 (MEK2)/extracellular signal-regulated kinase 2 (ERK2) signaling pathway was found to be correlated with the cell dissociation induced by dissociation factor (DF) in pancreatic cancer cells. In this study, the expressions of epidermal growth factor receptor (EGFR), phosphorylated EGFR (p-EGFR), and its downstream kinases MEK1/2 and ERK1/2, were analyzed to clarify the regulatory mechanism of cell dissociation in pancreatic cancer cells. Two hamster (PC-1.0 and PC-1) and two human (AsPC-1 and Capan-2) pancreatic cancer cell lines were used. Immunocytochemical study was performed using anti-EGFR, p-EGFR, phosphorylated MEK1/2 (p-MEK1/2), and phosphorylated ERK1/2 (p-ERK1/2) antibodies. DF-treatment markedly induced the expressions of EGFR, p-EGFR, p-MEK1/2, p-ERK1/2, as well as the dissociation of cell colonies in PC-1 and Capan-2 cells. In contrast, AG1478 (an EGFR inhibitor) treatment significantly induced the cell aggregation in PC-1.0 and AsPC-1 cells which usually grew as single cells, but strongly suppressed the expressions of EGFR, p-EGFR, p-MEK1/2, and p-ERK1/2. These observations demonstrate that activation of EGFR is closely involved in cell dissociation in pancreatic cancer through activating MEK/ERK signaling pathway.
- SourceAvailable from: Belinda Sánchez Ramírez[Show abstract] [Hide abstract]
ABSTRACT: Epidermal Growth Factor Receptor (EGFR or HER1) is considered a tumor associated antigen. HER1 is overexpressed in many human epithelial tumors and involved in crucial cellular functions for tumor development. For this reason HER1 is considered a good target for cancer immunotherapy and some passive agents are being evaluated in clinical trials. However, HER1-based active immunotherapy has not been clinically explored. To develop an active immunotherapy approach based on HER1 for the treatment of HER1+ cancer patients, we cloned and expressed in mammalian cells the HER1 extracellular domain protein (HER1-ECD), which was specifically recognized by an anti- EGFR monoclonal antibody. HER1-ECD was purified by affinity chromatography and adjuvated in Very Small Size Proteoliposomes (VSSP) or Complete Freund adjuvant to immunize C57BL/6 mice. Immunization elicited specific humoral and cellular immune response. The polyclonal antibodies induced by immunization recognized the full length HER1 on the surface of a lung tumor cell line. These results suggest that HER1-ECD could be an appropriated antigen to induce specific immune response in patients with HER1+ tumors.
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ABSTRACT: Anti-epidermal growth factor receptor (EGFR) therapies have been proven clinical effectiveness for a variety of epithelial tumours. Vaccination of mice with the extracellular domain (ECD) of autologous EGFR overcome the tolerance to self-EGFR and has antimetastatic effect on EGFR+ tumour. Because EGF/EGFR-signalling plays an important role in the inflammation stage of wound healing, the main objective of this study was to explore the possible role of murine (m) EGFR-ECD vaccine in the croton-oil-induced ear oedema and wound healing process in mice as autologous experimental models, mimicking the possible post-surgical wound complication in patients treated with the human EGFR-ECD/VSSP vaccine. Mice were intramuscularly immunised four times; biweekly with the mEGFR-ECD/VSSP/Mont. Seven days after, 8 mm diameter, full-thickness skin wound was performed on the back of each animal. Immunisation induced a strong specific humoral response against the mEGFR-ECD protein and a DTH dose-response curve but interestingly, animals treated with mEGFR-ECD/VSSP/Mont had similar inflammatory and healing speed responses compared to control ones. These data suggest that application of mEGFR-ECD/VSSP vaccine as a therapeutic approach in cancer patients could not elicit a poor healing process after surgery.International Wound Journal 09/2012; · 1.60 Impact Factor
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ABSTRACT: Phosphatidylinositol-3-kinase (PI3K) activation involves the epidermal growth factor receptor (EGFR) and plays an important role in cell survival signaling in pancreaticobiliary cancer. EGFR gene mutations have been correlated with clinical response to EGFR inhibitors in patients with advanced non-small cell lung cancer. This study examined the prevalence of PIK3CA and EGFR mutations in pancreaticobiliary cancer where erlotinib, an EGFR inhibitor, is approved for therapy. Thirty patients who underwent pancreatectomy for pancreaticobiliary carcinoma were identified. Genomic DNA was extracted from formalin fixed paraffin embedded tumor and adjacent normal tissue, and exons 9 and 20 (for the PIK3CA gene) and exons 18-21 (for the EGFR gene) were amplified by PCR and sequenced. Literature review on EGFR and/or PIK3CA mutations in pancreaticobiliary adenocarcinomas was conducted. No mutations in either PIK3CA or EGFR genes were identified. The study identified one synonymous single nucleotide polymorphism (SNP) (rs1050171) in the coding region of EGFR. A previously unreported change, suspected to be a SNP, was observed in intron 18 of EGFR (IVS18+15, C>T). Review of the literature showed EGFR mutation rate of 2% and 10.5% in pancreatic and biliary tract carcinomas, respectively. PIK3CA mutations were found in 3.6% and 11.7% of pancreatic and biliary tract carcinomas, respectively. A low prevalence of EGFR or PIK3CA mutations exists in pancreatic cancer (<5%), indicating that mutation screening may not be as useful in determining prognosis or response to targeted inhibition.Journal of gastrointestinal oncology 03/2013; 4(1):20-9.