HEK Cell - Origin

Origin

HEK 293 cells were generated in the early 70s by transformation of cultures of normal human embryonic kidney cells with sheared adenovirus 5 DNA in Alex van der Eb's laboratory in Leiden, The Netherlands. The human embryonic kidney cells were obtained from a single apparently healthy fetus legally aborted under Dutch law; the identity of the mother and the reason for the abortion are no longer known. The kidney cells were originally cultured by van der Eb himself; the transformation by adenovirus was performed by Frank Graham in van der Eb's lab and were published in the late 1970s after Graham left Leiden for McMaster University in Canada. They are called HEK since they originated in human embryonic kidney cultures, 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, including neural crest cells, neurons and glia. 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.

HEK 293 cells have a very complex karyotype, exhibiting two or more copies of each chromosome and with a modal chromosome number of 64. They are described as hypotriploid, containing less than three times the number of chromosomes of a normal haploid human cell. Chromosomal abnormalities include a total of three copies of the X chromosome and four copies of chromosome N17 and N22. The presence of multiple X chromosomes and the lack of a Y chromosome suggest that the original fetus was of a baby girl.