A431 cells
Encyclopedia
A431 cells are a model cell line (epidermoid carcinoma) used in biomedical research
. More specifically, they 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)
. As such they are often used as a positive control
for EGFR expression
. They contain no functional p53
, a potent tumor suppressor gene
, and so are highly sensitive to mitogen
ic stimuli. A431 cells were established from an epidermoid carcinoma in the vulva
of an 85 year old female patient.
Epidermal growth factor (EGF)
stimulation of A431 cells induces rapid tyrosine
phosphorylation
of intracellular
signalling protein
s 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. Treatment with sertoli cell
secreted growth factor (SCSGF) strongly induces cell proliferation. Stimulation of A431 cells with phorbol esters induces expression of interleukin 1-related protein IL1H.
Biomedical research
Biomedical research , in general simply known as medical research, is the basic research, applied research, or translational research conducted to aid and support the body of knowledge in the field of medicine...
. More specifically, they are used in studies of the cell cycle
Cell cycle
The cell cycle, or cell-division cycle, is the series of events that takes place in a cell leading to its division and duplication . In cells without a nucleus , the cell cycle occurs via a process termed binary fission...
and cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
-associated cell signalling pathways since they express
Gene expression
Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product. These products are often proteins, but in non-protein coding genes such as ribosomal RNA , transfer RNA or small nuclear RNA genes, the product is a functional RNA...
abnormally high levels of the Epidermal growth factor receptor (EGFR)
Epidermal growth factor receptor
The epidermal growth factor receptor is the cell-surface receptor for members of the epidermal growth factor family of extracellular protein ligands...
. As such they are often used as a positive control
Scientific control
Scientific control allows for comparisons of concepts. It is a part of the scientific method. Scientific control is often used in discussion of natural experiments. For instance, during drug testing, scientists will try to control two groups to keep them as identical and normal as possible, then...
for EGFR expression
Gene expression
Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product. These products are often proteins, but in non-protein coding genes such as ribosomal RNA , transfer RNA or small nuclear RNA genes, the product is a functional RNA...
. They contain no functional p53
P53
p53 , is a tumor suppressor protein that in humans is encoded by the TP53 gene. p53 is crucial in multicellular organisms, where it regulates the cell cycle and, thus, functions as a tumor suppressor that is involved in preventing cancer...
, a potent tumor suppressor gene
Tumor suppressor gene
A tumor suppressor gene, or anti-oncogene, is a gene that protects a cell from one step on the path to cancer. When this gene is mutated to cause a loss or reduction in its function, the cell can progress to cancer, usually in combination with other genetic changes.-Two-hit hypothesis:Unlike...
, and so are highly sensitive to mitogen
Mitogen
A mitogen is a chemical substance that encourages a cell to commence cell division, triggering mitosis. A mitogen is usually some form of a protein.Mitogenesis is the induction of mitosis, typically via a mitogen....
ic stimuli. A431 cells were established from an epidermoid carcinoma in the vulva
Vulva
The vulva consists of the external genital organs of the female mammal. This article deals with the vulva of the human being, although the structures are similar for other mammals....
of an 85 year old female patient.
Epidermal growth factor (EGF)
Epidermal growth factor
Epidermal growth factor or EGF is a growth factor that plays an important role in the regulation of cell growth, proliferation, and differentiation by binding to its receptor EGFR...
stimulation of A431 cells induces rapid tyrosine
Tyrosine
Tyrosine or 4-hydroxyphenylalanine, is one of the 22 amino acids that are used by cells to synthesize proteins. Its codons are UAC and UAU. It is a non-essential amino acid with a polar side group...
phosphorylation
Phosphorylation
Phosphorylation is the addition of a phosphate group to a protein or other organic molecule. Phosphorylation activates or deactivates many protein enzymes....
of intracellular
Intracellular
Not to be confused with intercellular, meaning "between cells".In cell biology, molecular biology and related fields, the word intracellular means "inside the cell".It is used in contrast to extracellular...
signalling protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s which control cellular processes such as growth, proliferation and apoptosis
Apoptosis
Apoptosis is the process of programmed cell death that may occur in multicellular organisms. Biochemical events lead to characteristic cell changes and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation...
. 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
Cellular differentiation
In developmental biology, cellular differentiation is the process by which a less specialized cell becomes a more specialized cell type. Differentiation occurs numerous times during the development of a multicellular organism as the organism changes from a simple zygote to a complex system of...
. Treatment of A431 cells with bradykinin
Bradykinin
Bradykinin is a peptide that causes blood vessels to dilate , and therefore causes blood pressure to lower. A class of drugs called ACE inhibitors, which are used to lower blood pressure, increase bradykinin further lowering blood pressure...
reduces basal and EGF-induced EGFR phosphorylation. Treatment with sertoli cell
Sertoli cell
A Sertoli cell is a 'nurse' cell of the testes that is part of a seminiferous tubule.It is activated by follicle-stimulating hormone and has FSH-receptor on its membranes.-Functions:...
secreted growth factor (SCSGF) strongly induces cell proliferation. Stimulation of A431 cells with phorbol esters induces expression of interleukin 1-related protein IL1H.