Cell lines are used in research on cancer, HIV, and other major diseases, and they’re also used to create biological models of organs, like the heart.
Thanks to Linode for supporting this SciShow video! You can check them out and get a $100 60-day credit on a new Linode account. Human cell lines are groups of human cells that are modified to grow indefinitely and survive outside of a human body. The first human cell line was created in 1951, from cervical cancer cells taken from 31-year-old Henrietta Lacks. The cells retrieved from a biopsy were super hardy, and very easy to grow, making them ideal for researchers to test on. The knowledge gained from deriving HeLa cells allowed scientists to develop more cell lines. With those, they could closely study and test treatments on other diseases, understand gene functions, create artificial tissues, and more. In modern labs, cell lines are a very important tool, because they provide an unparalleled way for us to test things like medicines on real, complex biological systems. Using cell lines also means that researchers don’t have to start their research in humans or animals right off the bat. Cell lines are used in research on cancer, HIV, and other major diseases, and they’re also used to create biological models of organs, like the heart. Cell lines are an essential part of molecular biology, allowing researchers to understand processes in organisms smaller than bacteria. They are also cost-effective compared to other techniques, and can be obtained from private companies or non-profit cell banks. However, cell line contamination is a major problem that hinders research advances and invalidates research from years gone by. Estimates suggest that 18-36% of cell lines are contaminated, and mislabeled cell lines, such as the WSU-CLL cell line, can lead to researchers studying the wrong type of leukemia. Small differences matter in science, and this issue needs to be addressed. It’s like a fingerprint for cells, and it’s the gold standard for cell line authentication.
Different cancers are driven at the molecular level by different genes, so if you want to find those genes and understand how they work, you need the right cancer model. When it was discovered that the widely used WSU-CLL cell line was contaminated, organizations such as The International Cell Line Authentication Committee (ICLAC) took action to promote awareness of this issue. ICLAC conducted a case study which found that of 27 articles using WSU-CLL, 24 referred to it incorrectly and were cited a total of 848 times. The findings of these potentially flawed studies have real world impacts, as clinical trials proceed from evidence gathered from the cell line studies.
A great example of this is INT 407, a cell line originally derived from intestinal tissue which is used to study Crohn’s disease. However, this cell line has been taken over by HeLa: the cervical cancer cell line. Vendors for INT 407 specifically state that this cell line is now indistinguishable from HeLa.
Though researchers have made great progress when it comes to Crohn’s disease, it is important to build clinical trials on the best possible foundations. To do this, researchers must ensure that they are using the right cells and are following best practice guidelines when handling them. This includes labeling each cell culture with the name of the cell line and relevant info, discarding used pipettes properly, and cleaning workbenches with 70% alcohol.
DNA analysis, such as Short Tandem Repeat (STR) sequencing, is the gold standard for cell line authentication and can help researchers verify the integrity of their data. Strings of repeated DNA bases make up around 3% of the human genome, and they are so variable that they differ between individuals. Therefore, scientists can use the number of repeats like a kind of fingerprint. Once the sample has been sequenced, particular repeats can be compared to a database of cell line DNA. If the number of repeats in the sample matches those listed against the intended cell line’s database entry, it means that the cells in the cell line genetically match with the cell type the researcher intended to work with. However, contamination can happen quickly, especially in a lab that handles multiple cell lines, so regular retests are recommended. Additionally, this method might not work for some older cell lines, since a lot of the original samples weren’t kept. Although it is a good way to make sure that the research being conducted is correct, many labs and authors elect not to. Organizations such as ICLAC are asking researchers to be more proactive in this regard. Fortunately, the more we learn about cells, the more we learn about how to use them to do science responsibly.
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