Origins of the HEK293 Cell Line:
HEK293 is a cell line derived from human embryonic kidney cells grown in tissue culture. They are also known, more informally, as HEK cells. This particular line was initiated by the transformation and culturing of normal HEK cells with sheared adenovirus 5 DNA. The transformation resulted in the incorporation of approximately 4.5 kilobases from the viral genome into human chromosome 19 of the HEK cells. The line was cultured by scientist Alex Van der Eb, in the early 1970s, at his lab at the University of Leiden, Holland. The transformation was executed by Frank Graham, another scientist Van der Eb’s lab, who invented the calcium phosphate method for transfecting cells. The source of the cells was a healthy, aborted fetus. The name HEK293 is thusly named because it was Frank Graham’s 293rd experiment.
The type of kidney cell that the HEK293 cell line is unknown, and it is difficult to conclusively characterize the cells post-transformation, since adenovirus 5 could have significantly disrupted cell morphology and expression, and embryonic kidneys are a heterogenous mix of almost all the types of cells present in the body. In fact, it has been speculated by independent researchers, including Van der Eb himself, that the cells may be neuronal in origin. This is possible, although most cells derived from an embryonic kidney would be endothelial, epithelial, or fibroblasts. Neuronal origin is suspected because of the presence of the presence of mRNA and gene products typically found in neurons.
Expression in HEK293:
- Corticotrophin releasing factor type 1 receptor
- Sphingosine-1-phosphate receptors EDG1, EDG3 and EDG5
- Muscarinic acetylcholine receptor M3
- Transient receptor potential TRPC1, TRPC3, TRPC4, TRPC6
The modal chromosome number for HEK293 cells is 64, which occurs in 60% of cells. Cells with higher ploidies occur less frequently, at a rate of 4.2%. HEK293 cell lines display some cytogenetic instability.