There is a discussion brewing in the US of adding Harriet Tubman to the $20 bill. While I welcome this discussion and hope it will become a reality soon, I would like to dedicate this article to yet another woman (remarkable in my opinion) who has impacted our lives, but not in an obvious way. Here is the story of Henrietta Lacks, but before I start talking about her contribution to the medical field, I would like to briefly explain about drug development which follows common steps for various diseases including cancer.
Cells growing in a petri dish
Cancer (and other disease) drugs prior to being tested on human patients for their effectiveness and safety, are first screened in various living models. This work is termed pre-clinical research which starts in the lab of universities or companies with the discovery of potential drugs for cancer and other diseases. The potential drugs are tested in in vitro and in vivo models to test for their safety and efficacy and help to correlate with clinical data. Promising cancer drug candidates are tested in a series of cell cultures which are derived from human cells. These cells themselves are cancerous in nature and form a part of in vitro models. While in vivo models use animals such as mice for testing potential candidates and this is the second stage of the pre-clinical research.
I am going to elaborate on in vitro cell culture models as this is where Henrietta Lacks impact has been felt even to this day. Growing and maintaining cell cultures outside the human body and in a petri dish is a very complex and challenging process. The first description of tissue culture was described in 1907 by researchers at John Hopkins University who were able to successfully grow cells outside the body. This possibility of growing cells paved the way for researchers (in 1911) from Rockefeller Institute of Medical Research to successfully grow chicken embryos in petri dishes, thus creating a foundation of processes for in vitro models. Scientists were then able to grow cancerous cells obtained from rats, dogs and humans. The biggest challenge however with these cell lines was that they only survived a few days which didn’t really give much insight since the monitoring of the effects of drugs or of the cancerous cell division was drastically cut short. It was due to these challenges, researchers were constantly looking for cells which could be grown for prolonged periods of time. On Feb 1st of 1951 (exactly 70 years ago this week), a 31 year old woman named Henrietta Lacks visited John Hopkins as she had a painful tumor in her cervix along with vaginal bleeding. The examining doctor collected a few cells from her tumor for testing and noticed that morphologically they looked very different from the tumor cells seen before. These cells were also able to survive and grow for prolonged periods of time. The examining doctor was able to isolate certain individual cell types and grow them successfully, thus creating HeLa cell lines. This cell line can double in cell count every 24 hours and the reason why these cells could grow so quickly was because Henrietta Lacks unfortunately also had contracted syphilis which overall had weakened her immunity, resulting in making this cancer more aggressive. Recently (in 2013) the exact reason for this fast multiplication was pinpointed to the fact that the HPV genome had inserted itself close to a proto-oncogene rendering a fast growth. While the viral genome contributed to the growth, the regeneration of telomeres after each cell division due to an overactive telomerase rendered them to be youthful, thus contributing to immortality.
Cell culture
Even though HeLa cell line is a cancer cell line, it has touched a wide area of medical research such as development of polio vaccine, studying effects of zero gravity in outer space, studying many dreadful diseases such as HIV/AIDS and leukaemia. More importantly, Henrietta’s cells also taught us a great deal about Ethics in medical research. It took 25 years since the first cell line was established for Henrietta’s family to become aware of how her cells were used which obviously was done without her consent. I would highly recommend our readers to please read the book “The Immortal Life of Henrietta Lacks” by Rebecca Skloot which inspired me many years ago. I am very grateful to Henrietta Lacks and her family’s generosity in letting the world use her cell lines, Thank you.
Royalty free images were used.
