A431 cells are a model human cell line (epidermoid carcinoma) used in biomedical research. [1]
A431 cells were established from an epidermoid carcinoma in the skin (epidermis) of an 85- year-old female patient. Epidermal growth factor (EGF) stimulation of A431 cells induces rapid tyrosine phosphorylation of intracellular signaling proteins which control cellular processes such as growth, proliferation and apoptosis. At low (picomolar) concentrations, EGF promotes cell growth of A431 cells whereas at higher (nanomolar) concentrations it inhibits growth by causing the cells to terminally differentiate. Treatment of A431 cells with bradykinin reduces basal and EGF-induced EGFR phosphorylation. [2] Treatment with Sertoli cell secreted growth factor (SCSGF) strongly induces cell proliferation. [3] [4] Stimulation of A431 cells with phorbol esters induces expression of interleukin 1-related protein IL1H.
A431 cells are used in studies of the cell cycle and cancer-associated cell signalling pathways since they express abnormally high levels of the Epidermal growth factor receptor (EGFR). They are often used as a positive control for EGFR expression. They contain no functional p53, a potent tumor suppressor gene, and are highly sensitive to mitogenic stimuli. In xenografts, A431 cells have shown antitumorigenic properties of introduced EGF and related radiation sensitization characteristics. Other in vitro studies have found EGF to also cause substantial lowering of DNA replication and protein synthesis. [5] The A431 lines engineered to express tumor antigens such as mesothelin [6] and GPC3 [7] have been made as cell models to test cancer therapeutics.
A tyrosine kinase is an enzyme that can transfer a phosphate group from ATP to the tyrosine residues of specific proteins inside a cell. It functions as an "on" or "off" switch in many cellular functions.
Autocrine signaling is a form of cell signaling in which a cell secretes a hormone or chemical messenger that binds to autocrine receptors on that same cell, leading to changes in the cell. This can be contrasted with paracrine signaling, intracrine signaling, or classical endocrine signaling.
Epidermal growth factor (EGF) is a protein that stimulates cell growth and differentiation by binding to its receptor, EGFR. Human EGF is 6-kDa and has 53 amino acid residues and three intramolecular disulfide bonds.
A mitogen is a peptide or small protein that induces a cell to begin cell division: mitosis. Mitogenesis is the induction (triggering) of mitosis, typically via a mitogen. The mechanism of action of a mitogen is that it triggers signal transduction pathways involving mitogen-activated protein kinase (MAPK), leading to mitosis.
The epidermal growth factor receptor is a transmembrane protein that is a receptor for members of the epidermal growth factor family of extracellular protein ligands.
The MAPK/ERK pathway is a chain of proteins in the cell that communicates a signal from a receptor on the surface of the cell to the DNA in the nucleus of the cell.
Receptor tyrosine kinases (RTKs) are the high-affinity cell surface receptors for many polypeptide growth factors, cytokines, and hormones. Of the 90 unique tyrosine kinase genes identified in the human genome, 58 encode receptor tyrosine kinase proteins. Receptor tyrosine kinases have been shown not only to be key regulators of normal cellular processes but also to have a critical role in the development and progression of many types of cancer. Mutations in receptor tyrosine kinases lead to activation of a series of signalling cascades which have numerous effects on protein expression. Receptor tyrosine kinases are part of the larger family of protein tyrosine kinases, encompassing the receptor tyrosine kinase proteins which contain a transmembrane domain, as well as the non-receptor tyrosine kinases which do not possess transmembrane domains.
Transforming growth factor alpha (TGF-α) is a protein that in humans is encoded by the TGFA gene. As a member of the epidermal growth factor (EGF) family, TGF-α is a mitogenic polypeptide. The protein becomes activated when binding to receptors capable of protein kinase activity for cellular signaling.
Matuzumab is a humanized monoclonal antibody for the treatment of cancer. It binds to the epidermal growth factor receptor (EGFR) with high affinity. The mouse monoclonal antibody (mAb425) from which matuzumab was developed at the Wistar Institute in Philadelphia, Pennsylvania
Zalutumumab is a fully human IgG1 monoclonal antibody (mAb) directed towards the epidermal growth factor receptor (EGFR). It is a product developed by Genmab in Utrecht, the Netherlands. Specifically, zalutumumab is designed for the treatment of squamous cell carcinoma of the head and neck (SCCHN), a type of cancer.
The ErbB family of proteins contains four receptor tyrosine kinases, structurally related to the epidermal growth factor receptor (EGFR), its first discovered member. In humans, the family includes Her1, Her2, Her3 (ErbB3), and Her4 (ErbB4). The gene symbol, ErbB, is derived from the name of a viral oncogene to which these receptors are homologous: erythroblastic leukemia viral oncogene. Insufficient ErbB signaling in humans is associated with the development of neurodegenerative diseases, such as multiple sclerosis and Alzheimer's Disease, while excessive ErbB signaling is associated with the development of a wide variety of types of solid tumor.
Heparin-binding EGF-like growth factor (HB-EGF) is a member of the EGF family of proteins that in humans is encoded by the HBEGF gene.
Betacellulin is a protein that in humans is encoded by the BTC gene located on chromosome 4 at locus 4q13-q21. Betacellulin, is a part of an Epidermal Growth Factor (EGF) family that has been spotted in the conditioned cell lines that was taken from mice pancreatic Beta cell tumor. When a sequence of the purified protein and a cloned cDNA was extracted, it supported the claim that in fact betacellulin is a new ligand formed from the epidermal growth factor receptor (EGFR). As the role a EGFR, betacellulin is manifested by different form of muscles and tissues, it also has a great effect of nitrogen that is used for retinal pigment epithelial cells and vascular smooth muscle cells. While many studies attest a role for betacellulin in the differentiation of pancreatic β-cells, the last decade witnessed the association of betacellulin with many additional biological processes, ranging from reproduction to the control of neural stem cells. Betacellulin is a member of the EGF family of growth factors. It is synthesized primarily as a transmembrane precursor, which is then processed to mature molecule by proteolytic events. This protein is a ligand for the EGF receptor.
SHC-transforming protein 1 is a protein that in humans is encoded by the SHC1 gene. SHC has been found to be important in the regulation of apoptosis and drug resistance in mammalian cells.
Mucin 1, cell surface associated (MUC1), also called polymorphic epithelial mucin (PEM) or epithelial membrane antigen or EMA, is a mucin encoded by the MUC1 gene in humans. MUC1 is a glycoprotein with extensive O-linked glycosylation of its extracellular domain. Mucins line the apical surface of epithelial cells in the lungs, stomach, intestines, eyes and several other organs. Mucins protect the body from infection by pathogen binding to oligosaccharides in the extracellular domain, preventing the pathogen from reaching the cell surface. Overexpression of MUC1 is often associated with colon, breast, ovarian, lung and pancreatic cancers. Joyce Taylor-Papadimitriou identified and characterised the antigen during her work with breast and ovarian tumors.
Receptor tyrosine-protein kinase erbB-3, also known as HER3, is a membrane bound protein that in humans is encoded by the ERBB3 gene.
Proto-oncogene tyrosine-protein kinase Src, also known as proto-oncogene c-Src, or simply c-Src, is a non-receptor tyrosine kinase protein that in humans is encoded by the SRC gene. It belongs to a family of Src family kinases and is similar to the v-Src gene of Rous sarcoma virus. It includes an SH2 domain, an SH3 domain and a tyrosine kinase domain. Two transcript variants encoding the same protein have been found for this gene.
An oncoantigen is a surface or soluble tumor antigen that supports tumor growth. A major problem of cancer immunotherapy is the selection of tumor cell variants that escape immune recognition. The notion of oncoantigen was set forth in the context of cancer immunoprevention to define a class of persistent tumor antigens not prone to escape from immune recognition.
A tyrosine kinase inhibitor (TKI) is a pharmaceutical drug that inhibits tyrosine kinases. Tyrosine kinases are enzymes responsible for the activation of many proteins by signal transduction cascades. The proteins are activated by adding a phosphate group to the protein (phosphorylation), a step that TKIs inhibit. TKIs are typically used as anticancer drugs. For example, they have substantially improved outcomes in chronic myelogenous leukemia.
AEE788 is a multitargeted human epidermal receptor (HER) 1/2 and vascular endothelial growth factor receptor (VEGFR) 1/2 receptor family tyrosine kinases inhibitor with IC50 of 2, 6, 77, 59 nM for EGFR, ErbB2, KDR, and Flt-1. In cells, growth factor-induced EGFR and ErbB2 phosphorylation was also efficiently inhibited with IC50s of 11 and 220 nM, respectively. It efficiently inhibited growth factor-induced EGFR and ErbB2 phosphorylation in tumors for >72 h, a phenomenon correlating with the antitumor efficacy of intermittent treatment schedules. It also inhibits VEGF-induced angiogenesis in a murine implant model. It has potential as an anticancer agent targeting deregulated tumor cell proliferation as well as angiogenic parameters.