HeLa
Encyclopedia
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
type in an immortal cell line
Immortalised cell line
An immortalised cell line is population of cells from a multicellular organism which would normally not proliferate indefinitely but, due to mutation, have evaded normal cellular senescence and instead can keep undergoing division. The cells can therefore be grown for prolonged periods in vitro...
used in scientific research. It is the oldest and most commonly used human cell line. The line was derived from cervical cancer
Cervical cancer
Cervical cancer is malignant neoplasm of the cervix uteri or cervical area. One of the most common symptoms is abnormal vaginal bleeding, but in some cases there may be no obvious symptoms until the cancer is in its advanced stages...
cells taken on February 8, 1951 from Henrietta Lacks
Henrietta Lacks
Henrietta Lacks was an African-American woman who was the unwitting source of cells from her cancerous tumor, which were cultured by George Otto Gey to create an immortal cell line for medical research...
, a patient who eventually died of her cancer on October 4, 1951. The cell line was found to be remarkably durable and prolific as illustrated by its contamination of many other cell lines used in research.
George Otto Gey and Henrietta Lacks
George Otto Gey
George Otto Gey was the scientist who propagated the HeLa cell line.-Biography:Gey was born in Pennsylvania, and both his parents were born in Germany. He received his undergraduate degree at the University of Pittsburgh in 1921 and then taught zoology there. Around 1926 he married Margaret K. ,...
shortly before Lacks died in 1951. This was the first human cell line to prove successful in vitro, which was a scientific achievement with profound future benefit to medical research. Gey freely donated both the cells and the tools and processes his lab developed to any scientist requesting them, simply for the benefit of science. Neither Lacks nor her family gave Gey permission to harvest the cells, but, at that time, permission was neither required nor customarily sought. The cells were later commercialized, although never patented in their original form. Then, as now, there was no requirement to inform a patient, or their relatives, about such matters because discarded material, or material obtained during surgery, diagnosis, or therapy, was the property of the physician and/or medical institution. This issue and Mrs. Lacks' situation was brought up in the Supreme Court of California case of Moore v. Regents of the University of California. The court ruled that a person's discarded tissue and cells are not their property and can be commercialized.
At first, the cell line was said to be named after a "Helen Lane" or "Helen Larson", in order to preserve Lacks' anonymity. Despite this attempt, her real name was used by the press within a few years of her death. These cells are treated as cancer cells, as they are descended from a biopsy taken from a visible lesion on the cervix as part of Mrs. Lacks' diagnosis of cancer. A debate still continues on the classification of the cells.
HeLa cells are termed "immortal" in that they can divide an unlimited number of times in a laboratory cell culture plate as long as fundamental cell survival conditions are met (i.e. being maintained and sustained in a suitable environment). There are many strain
Strain (biology)
In biology, a strain is a low-level taxonomic rank used in three related ways.-Microbiology and virology:A strain is a genetic variant or subtype of a micro-organism . For example, a "flu strain" is a certain biological form of the influenza or "flu" virus...
s of HeLa cells as they continue to evolve by being grown in cell 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,...
s, but all HeLa cells are descended from the same tumor cells removed from Mrs. Lacks. It has been estimated that the total number of HeLa cells that have been propagated in cell culture far exceeds the total number of cells that were in Henrietta Lacks' body.
Use in research
HeLa cells were used by Jonas SalkJonas Salk
Jonas Edward Salk was an American medical researcher and virologist, best known for his discovery and development of the first safe and effective polio vaccine. He was born in New York City to parents from Ashkenazi Jewish Russian immigrant families...
to test the first polio vaccine
Polio vaccine
Two polio vaccines are used throughout the world to combat poliomyelitis . The first was developed by Jonas Salk and first tested in 1952. Announced to the world by Salk on April 12, 1955, it consists of an injected dose of inactivated poliovirus. An oral vaccine was developed by Albert Sabin...
in the 1950s. Since that time, HeLa cells have been used for "research into cancer, AIDS, the effects of radiation and toxic substances, gene mapping, and many other scientific pursuits". According to author Rebecca Skloot
Rebecca Skloot
Rebecca L. Skloot is a freelance science writer who specializes in science and medicine. Her first book, The Immortal Life of Henrietta Lacks , was one of the best-selling new books of the year, staying on the New York Times Bestseller List for over 32 weeks and optioned to be made into a movie by...
, by 2009, "more than 60,000 scientific articles had been published about research done on HeLa, and that number was increasing steadily at a rate of more than 300 papers each month."
Telomerase
The HeLa cell line was derived for use in cancer researchCancer research
Cancer research is basic research into cancer in order to identify causes and develop strategies for prevention, diagnosis, treatments and cure....
. These cells proliferate abnormally rapidly, even compared to other cancer cells. In Rebecca Skloot
Rebecca Skloot
Rebecca L. Skloot is a freelance science writer who specializes in science and medicine. Her first book, The Immortal Life of Henrietta Lacks , was one of the best-selling new books of the year, staying on the New York Times Bestseller List for over 32 weeks and optioned to be made into a movie by...
's The Immortal Life of Henrietta Lacks
The Immortal Life of Henrietta Lacks
The Immortal Life of Henrietta Lacks is a non-fiction book by American author Rebecca Skloot. It is about Henrietta Lacks and the immortal cell line, known as HeLa, that came from her cervical cancer cells in 1951. The book is notable for its accessible science writing and dealing with ethical...
, she explains that HeLa cells have an active version of telomerase
Telomerase
Telomerase is an enzyme that adds DNA sequence repeats to the 3' end of DNA strands in the telomere regions, which are found at the ends of eukaryotic chromosomes. This region of repeated nucleotide called telomeres contains non-coding DNA material and prevents constant loss of important DNA from...
during cell division, which prevents the incremental shortening of telomere
Telomere
A telomere is a region of repetitive DNA sequences at the end of a chromosome, which protects the end of the chromosome from deterioration or from fusion with neighboring chromosomes. Its name is derived from the Greek nouns telos "end" and merοs "part"...
s that is implicated in aging and eventual cell death. In this way, HeLa cells circumvent the Hayflick Limit
Hayflick limit
The Hayflick limit is the number of times a normal cell population will divide before it stops, presumably because the telomeres reach a critical length....
, which is the limited number of cell divisions that most normal cells can later undergo before becoming senescent
Senescence
Senescence or biological aging is the change in the biology of an organism as it ages after its maturity. Such changes range from those affecting its cells and their function to those affecting the whole organism...
.
Chromosome number
Horizontal gene transferHorizontal gene transfer
Horizontal gene transfer , also lateral gene transfer , is any process in which an organism incorporates genetic material from another organism without being the offspring of that organism...
from human papillomavirus
Human papillomavirus
Human papillomavirus is a member of the papillomavirus family of viruses that is capable of infecting humans. Like all papillomaviruses, HPVs establish productive infections only in keratinocytes of the skin or mucous membranes...
18 (HPV18) to human
Human
Humans are the only living species in the Homo genus...
cervical cells created the HeLa genome which is different from either parent genome in various ways including its number of chromosomes. HeLa cells have a modal chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
number of 82, with four copies of chromosome 12 and three copies of chromosomes 6, 8, and 17.
Human papillomaviruses (HPVs) are frequently integrated into the cellular DNA in cervical cancers. We mapped by FISHFluorescent in situ hybridizationFISH is a cytogenetic technique developed by biomedical researchers in the early 1980s that is used to detect and localize the presence or absence of specific DNA sequences on chromosomes. FISH uses fluorescent probes that bind to only those parts of the chromosome with which they show a high...
five HPV18 integration sites: three on normal chromosomes 8 at 8q24 and two on derivative chromosomes, der(5)t(5;22;8)(q11;q11q13;q24) and der(22)t(8;22)(q24;q13), which have chromosome 8q24 material. An 8q24 copy number increase was detected by CGH. Dual-color FISH with a c-MYC probe mapping to 8q24 revealed colocalization with HPV18 at all integration sites, indicating that dispersion and amplification of the c-MYC gene sequences occurred after and was most likely triggered by the viral insertion at a single integration site. Numerical and structural chromosomal aberrations identified by SKY, genomic imbalances detected by CGH, as well as FISH localization of HPV18 integration at the c-MYC locus in HeLa cells are common and representative for advanced stage cervical cell carcinomas. The HeLa genome has been remarkably stable after years of continuous cultivation; therefore, the genetic alterations detected may have been present in the primary tumor and reflect events that are relevant to the development of cervical cancer.
Contamination
Because of their adaptation to growth in tissue culture plates, HeLa cells are sometimes difficult to control. They have proven to be a persistent laboratory "weedWeed
A weed in a general sense is a plant that is considered by the user of the term to be a nuisance, and normally applied to unwanted plants in human-controlled settings, especially farm fields and gardens, but also lawns, parks, woods, and other areas. More specifically, the term is often used to...
" that contaminates other cell cultures in the same laboratory, interfering with biological research and forcing researchers to declare many results invalid. The degree of HeLa cell contamination among other cell types is unknown because few researchers test the identity or purity of already-established cell lines. It has been demonstrated that a substantial fraction of in vitro
In vitro
In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...
cell lines — approximately 10%, maybe 20% — are contaminated with HeLa cells. Stanley Gartler
Stanley Gartler
Stanley Michael Gartler is a cell and molecular biologist and human geneticist. He was the first scientist to offer conclusive evidence for the clonality of human cancers. He and Walter Nelson-Rees identified that HeLa cells had contaminated many cell lines thought to be unique...
in 1967 and Walter Nelson-Rees
Walter Nelson-Rees
Walter Nelson-Rees was a cell culture worker and cytogeneticist who helped expose the problem of cross-contamination of cell lines. Nelson-Rees used chromosome banding to show that many immortal cell lines, previously thought to be unique, were actually HeLa cell lines...
in 1975 were the first to publish on the contamination of various cell lines by HeLa.
Science writer Michael Gold wrote about the HeLa cell contamination problem in his book A Conspiracy of Cells. He describes Nelson-Rees's identification of this pervasive worldwide problem — affecting even the laboratories of the best physicians, scientists, and researchers, including Jonas Salk
Jonas Salk
Jonas Edward Salk was an American medical researcher and virologist, best known for his discovery and development of the first safe and effective polio vaccine. He was born in New York City to parents from Ashkenazi Jewish Russian immigrant families...
— and many, possibly career-ending, efforts to address it. According to Gold, the HeLa contamination problem almost led to a Cold War
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...
incident: The USSR and the USA had begun to cooperate in the war on cancer
War on Cancer
The War on Cancer refers to the effort to find a cure for cancer by increased research to improve the understanding of cancer biology and the development of more effective cancer treatments, such as targeted drug therapies. The aim of such efforts is to eradicate cancer as a major cause of death....
launched by President Richard Nixon
Richard Nixon
Richard Milhous Nixon was the 37th President of the United States, serving from 1969 to 1974. The only president to resign the office, Nixon had previously served as a US representative and senator from California and as the 36th Vice President of the United States from 1953 to 1961 under...
only to find that the exchanged cells were contaminated by HeLa. Gold contends that the HeLa problem was amplified by emotions, egos, and a reluctance to admit mistakes. Nelson-Rees explains:
It's all human - an unwillingness to throw away hours and hours of what was thought to be good research...worries about jeopardizing another grant that's being applied for, the hurrying to come out with a paper first. And it isn't limited to biology and cancer research. Scientists in many endeavors all make mistakes, and they all have the same problems.
Rather than focus on how to resolve the problem of HeLa cell contamination, many scientists and science writers continue to document this problem as simply a contamination issue — caused not by human error or shortcomings but by the hardiness, proliferating, or overpowering nature of HeLa. Recent data suggest that cross-contaminations are still a major ongoing problem with modern cell cultures.
Helacyton gartleri
Due to their ability to replicate indefinitely, and their non-human number of chromosomes, HeLa was described by Leigh Van ValenLeigh Van Valen
Leigh Maiorana Van Valen was an American evolutionary biologist. He was professor emeritus in the Department of Ecology and Evolution at the University of Chicago....
as an example of the contemporary creation of a new species, Helacyton gartleri. The species was named after Stanley M. Gartler, whom Van Valen credits with discovering "the remarkable success of this species." His argument for speciation depends on three points:
- The chromosomal incompatibility of HeLa cells with humans.
- The ecological niche of HeLa cells.
- Their ability to persist and expand well beyond the desires of human cultivators.
This definition has not been followed by others in the scientific community, nor, indeed, has it been widely noted.
As well as proposing a new species for HeLa cells, Van Valen proposed in the same paper the new family Helacytidae and the genus Helacyton. Recognition of Van Valen and Maiorana's names, however, renders Homo and Hominidae paraphyletic
Paraphyly
A group of taxa is said to be paraphyletic if the group consists of all the descendants of a hypothetical closest common ancestor minus one or more monophyletic groups of descendants...
because Helacyton gartleri is most closely related to Homo sapiens.
See also
- Canine transmissible venereal tumorCanine transmissible venereal tumorCanine transmissible venereal tumor , also called transmissible venereal tumor , Canine transmissible venereal sarcoma , Sticker tumor and infectious sarcoma is a histiocytic tumor of the dog and other canids that mainly affects the external genitalia, and is transmitted from animal to animal...
– infectious cancer in dogs and other canids caused by an immortal cell line - Devil facial tumour diseaseDevil facial tumour diseaseDevil facial tumour disease is an aggressive non-viral transmissible parasitic cancer—which likely originated in Schwann cells—that affects Tasmanian devils. The first "official case" was described in 1996, in Australia...
– infectious cancer in the Tasmanian devilTasmanian DevilThe Tasmanian devil is a carnivorous marsupial of the family Dasyuridae, now found in the wild only on the Australian island state of Tasmania. The size of a small dog, it became the largest carnivorous marsupial in the world following the extinction of the thylacine in 1936...
caused by an immortal cell line - Henrietta LacksHenrietta LacksHenrietta Lacks was an African-American woman who was the unwitting source of cells from her cancerous tumor, which were cultured by George Otto Gey to create an immortal cell line for medical research...
– woman whose cancer cells were used to create HeLa - List of contaminated cell lines
External links
- HeLa Transfection and Selection Data for HeLa Cells
- Rebecca SklootRebecca SklootRebecca L. Skloot is a freelance science writer who specializes in science and medicine. Her first book, The Immortal Life of Henrietta Lacks , was one of the best-selling new books of the year, staying on the New York Times Bestseller List for over 32 weeks and optioned to be made into a movie by...
, The Immortal Life of Henrietta Lacks book website with additional features (photo/video/audio) - The Henrietta Lacks Foundation, a foundation established to, among other things, help provide scholarship funds and health insurance to Henrietta Lacks's family.
- Rebecca SklootRebecca SklootRebecca L. Skloot is a freelance science writer who specializes in science and medicine. Her first book, The Immortal Life of Henrietta Lacks , was one of the best-selling new books of the year, staying on the New York Times Bestseller List for over 32 weeks and optioned to be made into a movie by...
, Cells That Save Lives are a Mother's Legacy, New York Times - "Wonder Woman: The Life, Death, and Life After Death of Henrietta Lacks, Unwitting Heroine of Modern Medical Science" by Van Smith
- "What's Left of Henrietta Lacks?" by Anne Enright
- "Culturing Life: How Cells Became Technologies" a book by Hannah LandeckerHannah LandeckerHannah Landecker is an author and Associate Professor of Sociology at UCLA. Her research interests are the social and historical study of biotechnology and life science, from 1900 to the present, the intersections of biology and technology, with a particular focus on cells, and the in vitro...
about HeLa and the history of tissue culture. - Discussion about the taxonomic effect of creating the new taxon Helacyton.
- Cell Centered Database – HeLa cell
- Helen Lane
- HeLa Cells
- "The Way of All Flesh" a documentary by Adam CurtisAdam CurtisAdam Curtis is a British BAFTA winning documentarian and a writer, television producer, director and narrator. He works for BBC Current Affairs.-Early life and education:Curtis was born in 1955...
. - Audio Interview with Rebecca Skloot about her book "The Immortal Life of Henrietta Lacks"