HEK cell
Encyclopedia
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
nic kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
cells grown in tissue culture
Tissue culture
Tissue culture is the growth of tissues or cells separate from the organism. This is typically facilitated via use of a liquid, semi-solid, or solid growth medium, such as broth or agar...
. HEK 293 cells are very easy to grow and transfect
Transfection
Transfection is the process of deliberately introducing nucleic acids into cells. The term is used notably for non-viral methods in eukaryotic cells...
very readily and have been widely-used in cell biology
Cell biology
Cell biology is a scientific discipline that studies cells – their physiological properties, their structure, the organelles they contain, interactions with their environment, their life cycle, division and death. This is done both on a microscopic and molecular level...
research for many years. They are also used by the biotechnology
Biotechnology
Biotechnology is a field of applied biology that involves the use of living organisms and bioprocesses in engineering, technology, medicine and other fields requiring bioproducts. Biotechnology also utilizes these products for manufacturing purpose...
industry to produce therapeutic proteins and viruses for gene therapy
Gene therapy
Gene therapy is the insertion, alteration, or removal of genes within an individual's cells and biological tissues to treat disease. It is a technique for correcting defective genes that are responsible for disease development...
.
Origins of HEK 293 Cells
HEK 293 cells were generated in the early 70s by transformationTransformation (genetics)
In molecular biology transformation is the genetic alteration of a cell resulting from the direct uptake, incorporation and expression of exogenous genetic material from its surroundings and taken up through the cell membrane. Transformation occurs naturally in some species of bacteria, but it can...
of cultures of normal human embryonic kidney cells with sheared adenovirus 5 DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
in Alex Van der Eb's laboratory in Leiden, The Netherlands. The human embryonic kidney cells were obtained from a healthy aborted fetus and originally cultured by Van der Eb himself, and the transformation by adenovirus was performed by Frank Graham who published his findings in the late 1970s after he left Leiden for McMaster University
McMaster University
McMaster University is a public research university whose main campus is located in Hamilton, Ontario, Canada. The main campus is located on of land in the residential neighbourhood of Westdale, adjacent to Hamilton's Royal Botanical Gardens...
in Canada. They are called HEK for human embryonic kidney, while the number 293 comes from Graham's habit of numbering his experiments; the original HEK 293 cell clone was simply the product of his 293rd experiment.
Subsequent analysis has shown that the transformation was brought about by an insert consisting of ~4.5 kilobases from the left arm of the viral genome, which became incorporated into human chromosome 19.
For many years it was assumed that HEK 293 cells were generated by transformation of either a fibroblastic, endothelial or epithelial cell all of which are abundant in kidney. However the fact that the cells originated from cultured kidney cells does not
say much about the exact cellular origin of the HEK 293, as embryonic kidney cultures may contain small numbers of almost all cell types of the body. In fact Graham and coworkers more recently provided evidence that HEK 293 cells and several other human cell lines generated by adenovirus transformation of human embryonic kidney cells have many properties of immature neurons, suggesting that the adenovirus was taken up and transformed a neuronal lineage cell in the original kidney culture. As a consequence, HEK 293 cells may need to be re-characterized and should not be used as an in vitro model for kidney cell function or studies involving kidney cells.
Uses of HEK 293 Cells
As an experimentally transformed cell line, HEK 293 cells are not a particularly good model for normal cells, cancerCancer
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...
cells, or any other kind of cell that is a fundamental object of research. However, they are extremely easy to work with, being straightforward to culture
Cell culture
Cell culture is the complex process by which cells are grown under controlled conditions. In practice, the term "cell culture" has come to refer to the culturing of cells derived from singlecellular eukaryotes, especially animal cells. However, there are also cultures of plants, fungi and microbes,...
and to transfect
Transfection
Transfection is the process of deliberately introducing nucleic acids into cells. The term is used notably for non-viral methods in eukaryotic cells...
, and so can be used in experiments in which the behavior of the cell itself is not of interest. Typically, these experiments involve transfecting in a gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
(or combination of genes) of interest, and then analyzing the expressed 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...
; essentially, the cell is used simply as a test tube with a membrane. The widespread use of this cell line is due to its extreme transfectability by the various techniques, including calcium phosphate
Calcium phosphate
Calcium phosphate is the name given to a family of minerals containing calcium ions together with orthophosphates , metaphosphates or pyrophosphates and occasionally hydrogen or hydroxide ions ....
method, achieving efficiencies approaching 100%.
An important variant of this cell line is the 293T cell line that contains, in addition, the SV40 Large T-antigen
SV40 Large T-antigen
SV40 large T antigen is a hexamer protein that is a proto-oncogene derived from the polyomavirus SV40 which is capable of transforming a variety of cell types. The transforming activity of TAg is due in large part to its perturbation of the retinoblastoma and p53 tumor suppressor proteins...
, that allows for episomal replication of transfected plasmid
Plasmid
In microbiology and genetics, a plasmid is a DNA molecule that is separate from, and can replicate independently of, the chromosomal DNA. They are double-stranded and, in many cases, circular...
s containing the SV40 origin of replication. This allows for amplification of transfected plasmids and extended temporal expression of the desired gene products. Note that any similarly modified cell line can be used for this sort of work; HeLa
HeLa
A HeLa cell is a cell type in an immortal cell line used in scientific research. It is the oldest and most commonly used human cell line. The line was derived from cervical cancer cells taken on February 8, 1951 from Henrietta Lacks, a patient who eventually died of her cancer on October 4, 1951...
, COS
COS cells
COS is a cell line often used by biologists when studying the monkey virus SV40. Cells from this line are also often transfected to produce recombinant proteins for molecular biology, biochemistry, and cell biology experiments...
and Chinese Hamster Ovary cell
Chinese Hamster Ovary cell
Chinese hamster ovary cells are a cell line derived from the ovary of the Chinese hamster. They are often used in biological and medical research and commercially in the production of therapeutic proteins. They were introduced in the 1960s and grow as a cultured monolayer...
are common alternatives.
Examples of such experiments include:
- A study of the effects of a drug on sodium channels
- Testing of an inducible RNA interferenceRNA interferenceRNA interference is a process within living cells that moderates the activity of their genes. Historically, it was known by other names, including co-suppression, post transcriptional gene silencing , and quelling. Only after these apparently unrelated processes were fully understood did it become...
system - Testing of an isoform-selective protein kinase CProtein kinase CProtein kinase C also known as PKC is a family of enzymes that are involved in controlling the function of other proteins through the phosphorylation of hydroxyl groups of serine and threonine amino acid residues on these proteins. PKC enzymes in turn are activated by signals such as increases in...
agonist - Investigation of the interaction between two proteins
- Analysis of a nuclear export signalNuclear export signalA nuclear export signal is a short amino acid sequence of 4 hydrophobic residues in a protein that targets it for export from the cell nucleus to the cytoplasm through the nuclear pore complex using nuclear transport. It has the opposite effect of a nuclear localization signal, which targets a...
in a protein
A more specific use of HEK cells is in the propagation of adenoviral vectors. Viruses offer an extremely efficient means of delivering genes into cells, since this is what they have evolved to do, and are thus of great use as experimental tools. However, as pathogen
Pathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
s, they also present a degree of danger to the experimenter. This danger can be avoided by the use of viruses which lack key genes, and which are thus unable to replicate after entering a cell. In order to propagate such viral vectors, a cell line that expresses the missing genes is required. Since HEK cells express a number of adenoviral genes, they can be used to propagate adenoviral vectors in which these genes (typically, E1 and E3) are deleted, such as AdEasy.
293, and especially 293T, cells are commonly used for the production of various retroviral
Retrovirus
A retrovirus is an RNA virus that is duplicated in a host cell using the reverse transcriptase enzyme to produce DNA from its RNA genome. The DNA is then incorporated into the host's genome by an integrase enzyme. The virus thereafter replicates as part of the host cell's DNA...
vectors. Various retroviral packaging cell lines are based on these cells.
Native proteins of interest
Depending on various conditions, the gene expressionGene 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...
of HEK cells may vary. The following proteins of interest (among many others) are commonly found in untreated HEK cells:
- Corticotrophin releasing factor type 1 receptorCorticotropin releasing hormone receptor 1Corticotropin releasing hormone receptor 1 is a protein, also known as CRF1, with the latter now being the IUPHAR-recommended name...
- Sphingosine-1-phosphate receptorsLysophospholipid receptorThe lysophospholipid receptor group are members of the G protein-coupled receptor family of integral membrane proteins that are important for lipid signaling. In humans, there are eight LPL receptors, each encoded by a separate gene...
EDG1EDG1S1PR1 also known as S1P1 or EDG1 is a protein that in humans is encoded by the S1PR1 gene...
, EDG3EDG3Sphingosine-1-phosphate receptor 3 also known as S1PR3 is a human gene which encodes a G protein-coupled receptor which binds the lipid signaling molecule sphingosine 1-phosphate . Hence this receptor is also known as S1P3.- Function :...
and EDG5EDG5Sphingosine-1-phosphate receptor 2 also known as S1PR2 or S1P2 is a human gene which encodes a G protein-coupled receptor which binds the lipid signaling molecule sphingosine 1-phosphate .- Function :... - Muscarinic acetylcholine receptor M3Muscarinic acetylcholine receptor M3The muscarinic acetylcholine receptor M3, also known as the cholinergic receptor, muscarinic 3, is a muscarinic acetylcholine receptor. It is encoded by the human gene CHRM3....
- Transient receptor potentialTransient receptor potentialTransient receptor potential channels are a group of ion channels located mostly on the plasma membrane of numerous human and animal cell types. There are about 28 TRP channels that share some structural similarity to each other...
TRPC1TRPC1Transient receptor potential channel 1 is a protein that in humans is encoded by the TRPC1 gene.- Function :TRPC1 is an ion channel located on the plasma membrane of numerous human and animal cell types. It is a nonspecific cation channel, which means that both sodium and calcium ions can pass...
, TRPC3TRPC3Transient receptor potential cation channel, subfamily C, member 3, also known as TRPC3, is a human gene encoding a protein of the same name.-Interactions:TRPC3 has been shown to interact with TRPC1 and TRPC6.-Further reading:...
, TRPC4TRPC4Transient receptor potential cation channel, subfamily C, member 4, also known as TRPC4, is a human gene encoding a protein of the same name.-Interactions:TRPC4 has been shown to interact with TRPC1, ITPR1 and TRPC5.-Roles:...
, TRPC6TRPC6Transient receptor potential cation channel, subfamily C, member 6, also known as TRPC6, is a human gene encoding a protein of the same name. TRPC6 is a transient receptor potential ion channel...
External links
- HEK 293 Transfection and Selection Data @ Cell-culture Database
- HEK 293 Database
- 293 Cells (CRL-1573) in the ATCCAmerican Type Culture CollectionThe American Type Culture Collection is a private, not-for-profit biological resource center whose mission focuses on the acquisition, authentication, production, preservation, development and distribution of standard reference microorganisms, cell lines and other materials for research in the...
database - Transcript of FDA meeting, in which, starting page 77, Dr. Alex Van der Eb describes in detail the origin of HEK 293 cell