Henrietta Lacks' Cells Enabled Medical Breakthroughs. Is It Time to Finally Retire Them?
Sarah Watts is a health and science writer based in Chicago. Follow her on Twitter at @swattswrites.
For Victoria Tokarz, a third-year PhD student at the University of Toronto, experimenting with cells is just part of a day's work. Tokarz, 26, is studying to be a cell biologist and spends her time inside the lab manipulating muscle cells sourced from rodents to try to figure out how they respond to insulin. She hopes this research could someday lead to a breakthrough in our understanding of diabetes.
"People like to use HeLa cells because they're easy to use."
But in all her research, there is one cell culture that Tokarz refuses to touch. The culture is called HeLa, short for Henrietta Lacks, named after the 31-year-old tobacco farmer the cells were stolen from during a tumor biopsy she underwent in 1951.
"In my opinion, there's no question or experiment I can think of that validates stealing from and profiting off of a black woman's body," Tokarz says. "We're not talking about a reagent we created in a lab, a mixture of some chemicals. We're talking about a human being who suffered indescribably so we could profit off of her misfortune."
Lacks' suffering is something that, until recently, was not widely known. Born to a poor family in Roanoke, VA, Lacks was sent to live with her grandfather on the family tobacco farm at age four, shortly after the death of her mother. She gave birth to her first child at just fourteen, and two years later had another child with profound developmental disabilities. Lacks married her first cousin, David, in 1941 and the family moved to Maryland where they had three additional children.
But the real misfortune came in 1951, when Lacks told her cousins that she felt a hard "knot" in her womb. When Lacks went to Johns Hopkins hospital to have the knot examined, doctors discovered that the hard lump Henrietta felt was a rapidly-growing cervical tumor.
Before the doctors treated the tumor – inserting radium tubes into her vagina, in the hopes they could kill the cancer, Lacks' doctors clipped two tissue samples from her cervix, without Lacks' knowledge or consent. While it's considered widely unethical today, taking tissue samples from patients was commonplace at the time. The samples were sent to a cancer researcher at Johns Hopkins and Lacks continued treatment unsuccessfully until she died a few months later of metastatic cancer.
Lacks' story was not over, however: When her tissue sample arrived at the lab of George Otto Gey, the Johns Hopkins cancer researcher, he noticed that the cancerous cells grew at a shocking pace. Unlike other cell cultures that would die within a day or two of arriving at the lab, Lacks' cells kept multiplying. They doubled every 24 hours, and to this day, have never stopped.
Scientists would later find out that this growth was due to an infection of Human Papilloma Virus, or HPV, which is known for causing aggressive cancers. Lacks' cells became the world's first-ever "immortalized" human cell line, meaning that as long as certain environmental conditions are met, the cells can replicate indefinitely. Although scientists have cultivated other immortalized cell lines since then, HeLa cells remain a favorite among scientists due to their resilience, Tokarz says.
"People like to use HeLa cells because they're easy to use," Tokarz says. "They're easy to manipulate, because they're very hardy, and they allow for transection, which means expressing a protein in a cell that's not normally there. Other cells, like endothelial cells, don't handle those manipulations well."
Once the doctors at Johns Hopkins discovered that Lacks' cells could replicate indefinitely, they started shipping them to labs around the world to promote medical research. As they were the only immortalized cell line available at the time, researchers used them for thousands of experiments — some of which resulted in life-saving treatments. Jonas Salk's polio vaccine, for example, was manufactured using HeLa cells. HeLa cell research was also used to develop a vaccine for HPV, and for the development of in vitro fertilization and gene mapping. Between 1951 and 2018, HeLa cells have been cited in over 110,000 publications, according to a review from the National Institutes of Health.
But while some scientists like Tokarz are thankful for the advances brought about by HeLa cells, they still believe it's well past time to stop using them in research.
"Am I thankful we have a polio vaccine? Absolutely. Do I resent the way we came to have that vaccine? Absolutely," Tokarz says. "We could have still arrived at those same advances by treating her as the human being she is, not just a specimen."
Ethical considerations aside, HeLa is no longer the world's only available cell line – nor, Tokarz argues, are her cells the most suitable for every type of research. "The closer you can get to the physiology of the thing you're studying, the better," she says. "Now we have the ability to use primary cells, which are isolated from a person and put right into the culture dish, and those don't have the same mutations as cells that have been growing for 20 years. We didn't have the expertise to do that initially, but now we do."
Raphael Valdivia, a professor of molecular genetics and microbiology at Duke University School of Medicine, agrees that HeLa cells are no longer optimal for most research. "A lot of scientists are moving away from HeLa cells because they're so unstable," he says. "They mutate, they rearrange chromosomes to become adaptive, and different batches of cells evolve separately from each other. The HeLa cells in my lab are very different than the ones down the hall, and that means sometimes we can't replicate our results. We have to go back to an earlier batch of cells in the freezer and re-test."
Still, the idea of retiring the cells completely doesn't make sense, Valdivia says: "To some extent, you're beholden to previous research. You need to be able to confirm findings that happen in earlier studies, and to do that you need to use the same cell line that other researchers have used."
"Ethics is not black and white, and sometimes there's no such thing as a straightforward ethical or unethical choice."
"The way in which the cells were taken – without patient consent – is completely inappropriate," says Yann Joly, associate professor at the Faculty of Medicine in Toronto and Research Director at the Centre of Genomics and Policy. "The question now becomes, what can we do about it now? What are our options?"
While scientists are not able to erase what was done to Henrietta Lacks, Joly argues that retiring her cells is also non-consensual, assuming – maybe incorrectly – what Henrietta would have wanted, without her input. Additionally, Joly points out that other immortalized human cell lines are fraught with what some people consider to be ethical concerns as well, such as the human embryonic kidney cell line, commonly referred to as HEK-293, that was derived from an aborted female fetus. "Just because you're using another kind of cell doesn't mean it's devoid of ethical issue," he says.
Seemingly, the one thing scientists can agree on is that Henrietta Lacks was mistreated by the medical community. But even so, retiring her cells from medical research is not an obvious solution. Scientists are now using HeLa cells to better understand how the novel coronavirus affects humans, and this knowledge will inform how researchers develop a COVID-19 vaccine.
"Ethics is not black and white, and sometimes there's no such thing as a straightforward ethical or unethical choice," Joly says. "If [ethics] were that easy, nobody would need to teach it."
Sarah Watts is a health and science writer based in Chicago. Follow her on Twitter at @swattswrites.
Man Who Got the First Fecal Transplant to Cure Melanoma Shares His Experience
Jamie Rettinger was still in his thirties when he first noticed a tiny streak of brown running through the thumbnail of his right hand. It slowly grew wider and the skin underneath began to deteriorate before he went to a local dermatologist in 2013. The doctor thought it was a wart and tried scooping it out, treating the affected area for three years before finally removing the nail bed and sending it off to a pathology lab for analysis.
"I have some bad news for you; what we removed was a five-millimeter melanoma, a cancerous tumor that often spreads," Jamie recalls being told on his return visit. "I'd never heard of cancer coming through a thumbnail," he says. None of his doctors had ever mentioned it either. "I just thought I was being treated for a wart." But nothing was healing and it continued to bleed.
A few months later a surgeon amputated the top half of his thumb. Lymph node biopsy tested negative for spread of the cancer and when the bandages finally came off, Jamie thought his medical issues were resolved.
Melanoma is the deadliest form of skin cancer. About 85,000 people are diagnosed with it each year in the U.S. and more than 8,000 die of the cancer when it spreads to other parts of the body, according to the Centers for Disease Control and Prevention (CDC).
There are two peaks in diagnosis of melanoma; one is in younger women ages 30-40 and often is tied to past use of tanning beds; the second is older men 60+ and is related to outdoor activity from farming to sports. Light-skinned people have a twenty-times greater risk of melanoma than do people with dark skin.
"When I graduated from medical school, in 2005, melanoma was a death sentence" --Diwakar Davar.
Jamie had a follow up PET scan about six months after his surgery. A suspicious spot on his lung led to a biopsy that came back positive for melanoma. The cancer had spread. Treatment with a monoclonal antibody (nivolumab/Opdivo®) didn't prove effective and he was referred to the UPMC Hillman Cancer Center in Pittsburgh, a four-hour drive from his home in western Ohio.
An alternative monoclonal antibody treatment brought on such bad side effects, diarrhea as often as 15 times a day, that it took more than a week of hospitalization to stabilize his condition. The only options left were experimental approaches in clinical trials.
"When I graduated from medical school, in 2005, melanoma was a death sentence" with a cure rate in the single digits, says Diwakar Davar, 39, an oncologist at UPMC Hillman Cancer Center who specializes in skin cancer. That began to change in 2010 with introduction of the first immunotherapies, monoclonal antibodies, to treat cancer. The antibodies attach to PD-1, a receptor on the surface of T cells of the immune system and on cancer cells. Antibody treatment boosted the melanoma cure rate to about 30 percent. The search was on to understand why some people responded to these drugs and others did not.
At the same time, there was a growing understanding of the role that bacteria in the gut, the gut microbiome, plays in helping to train and maintain the function of the body's various immune cells. Perhaps the bacteria also plays a role in shaping the immune response to cancer therapy.
One clue came from genetically identical mice. Animals ordered from different suppliers sometimes responded differently to the experiments being performed. That difference was traced to different compositions of their gut microbiome; transferring the microbiome from one animal to another in a process known as fecal transplant (FMT) could change their responses to disease or treatment.
When researchers looked at humans, they found that the patients who responded well to immunotherapies had a gut microbiome that looked like healthy normal folks, but patients who didn't respond had missing or reduced strains of bacteria.
Davar and his team knew that FMT had a very successful cure rate in treating the gut dysbiosis of Clostridioides difficile, a persistant intestinal infection, and they wondered if a fecal transplant from a patient who had responded well to cancer immunotherapy treatment might improve the cure rate of patients who did not originally respond to immunotherapies for melanoma.
The ABCDE of melanoma detection
"It was pretty weird, I was totally blasted away. Who had thought of this?" Jamie first thought when the hypothesis was explained to him. But Davar's explanation that the procedure might restore some of the beneficial bacterial his gut was lacking, convinced him to try. He quickly signed on in October 2018 to be the first person in the clinical trial.
Fecal donations go through the same safety procedures of screening for and inactivating diseases that are used in processing blood donations to make them safe for transfusion. The procedure itself uses a standard hollow colonoscope designed to screen for colon cancer and remove polyps. The transplant is inserted through the center of the flexible tube.
Most patients are sedated for procedures that use a colonoscope but Jamie doesn't respond to those drugs: "You can't knock me out. I was watching them on the TV going up my own butt. It was kind of unreal at that point," he says. "There were about twelve people in there watching because no one had seen this done before."
A test two weeks after the procedure showed that the FMT had engrafted and the once-missing bacteria were thriving in his gut. More importantly, his body was responding to another monoclonal antibody (pembrolizumab/Keytruda®) and signs of melanoma began to shrink. Every three months he made the four-hour drive from home to Pittsburgh for six rounds of treatment with the antibody drug.
"We were very, very lucky that the first patient had a great response," says Davar. "It allowed us to believe that even though we failed with the next six, we were on the right track. We just needed to tweak the [fecal] cocktail a little better" and enroll patients in the study who had less aggressive tumor growth and were likely to live long enough to complete the extensive rounds of therapy. Six of 15 patients responded positively in the pilot clinical trial that was published in the journal Science.
Davar believes they are beginning to understand the biological mechanisms of why some patients initially do not respond to immunotherapy but later can with a FMT. It is tied to the background level of inflammation produced by the interaction between the microbiome and the immune system. That paper is not yet published.
It has been almost a year since the last in his series of cancer treatments and Jamie has no measurable disease. He is cautiously optimistic that his cancer is not simply in remission but is gone for good. "I'm still scared every time I get my scans, because you don't know whether it is going to come back or not. And to realize that it is something that is totally out of my control."
"It was hard for me to regain trust" after being misdiagnosed and mistreated by several doctors he says. But his experience at Hillman helped to restore that trust "because they were interested in me, not just fixing the problem."
He is grateful for the support provided by family and friends over the last eight years. After a pause and a sigh, the ruggedly built 47-year-old says, "If everyone else was dead in my family, I probably wouldn't have been able to do it."
"I never hesitated to ask a question and I never hesitated to get a second opinion." But Jamie acknowledges the experience has made him more aware of the need for regular preventive medical care and a primary care physician. That person might have caught his melanoma at an earlier stage when it was easier to treat.
Davar continues to work on clinical studies to optimize this treatment approach. Perhaps down the road, screening the microbiome will be standard for melanoma and other cancers prior to using immunotherapies, and the FMT will be as simple as swallowing a handful of freeze-dried capsules off the shelf rather than through a colonoscopy. Earlier this year, the Food and Drug Administration approved the first oral fecal microbiota product for C. difficile, hopefully paving the way for more.
An older version of this hit article was first published on May 18, 2021
Scientists want the salamander's secret: how they regenerate tissue
All organisms have the capacity to repair or regenerate tissue damage. None can do it better than salamanders or newts, which can regenerate an entire severed limb.
That feat has amazed and delighted man from the dawn of time and led to endless attempts to understand how it happens – and whether we can control it for our own purposes. An exciting new clue toward that understanding has come from a surprising source: research on the decline of cells, called cellular senescence.
Senescence is the last stage in the life of a cell. Whereas some cells simply break up or wither and die off, others transition into a zombie-like state where they can no longer divide. In this liminal phase, the cell still pumps out many different molecules that can affect its neighbors and cause low grade inflammation. Senescence is associated with many of the declining biological functions that characterize aging, such as inflammation and genomic instability.
Oddly enough, newts are one of the few species that do not accumulate senescent cells as they age, according to research over several years by Maximina Yun. A research group leader at the Center for Regenerative Therapies Dresden and the Max Planck Institute of Molecular and Cell Biology and Genetics, in Dresden, Germany, Yun discovered that senescent cells were induced at some stages of regeneration of the salamander limb, “and then, as the regeneration progresses, they disappeared, they were eliminated by the immune system,” she says. “They were present at particular times and then they disappeared.”
Senescent cells added to the edges of the wound helped the healthy muscle cells to “dedifferentiate,” essentially turning back the developmental clock of those cells into more primitive states.
Previous research on senescence in aging had suggested, logically enough, that applying those cells to the stump of a newly severed salamander limb would slow or even stop its regeneration. But Yun stood that idea on its head. She theorized that senescent cells might also play a role in newt limb regeneration, and she tested it by both adding and removing senescent cells from her animals. It turned out she was right, as the newt limbs grew back faster than normal when more senescent cells were included.
Senescent cells added to the edges of the wound helped the healthy muscle cells to “dedifferentiate,” essentially turning back the developmental clock of those cells into more primitive states, which could then be turned into progenitors, a cell type in between stem cells and specialized cells, needed to regrow the muscle tissue of the missing limb. “We think that this ability to dedifferentiate is intrinsically a big part of why salamanders can regenerate all these very complex structures, which other organisms cannot,” she explains.
Yun sees regeneration as a two part problem. First, the cells must be able to sense that their neighbors from the lost limb are not there anymore. Second, they need to be able to produce the intermediary progenitors for regeneration, , to form what is missing. “Molecularly, that must be encoded like a 3D map,” she says, otherwise the new tissue might grow back as a blob, or liver, or fin instead of a limb.
Another recent study, this time at the Mayo Clinic, provides evidence supporting the role of senescent cells in regeneration. Looking closely at molecules that send information between cells in the wound of a mouse, the researchers found that senescent cells appeared near the start of the healing process and then disappeared as healing progressed. In contrast, persistent senescent cells were the hallmark of a chronic wound that did not heal properly. The function and significance of senescence cells depended on both the timing and the context of their environment.
The paper suggests that senescent cells are not all the same. That has become clearer as researchers have been able to identify protein markers on the surface of some senescent cells. The patterns of these proteins differ for some senescent cells compared to others. In biology, such physical differences suggest functional differences, so it is becoming increasingly likely there are subsets of senescent cells with differing functions that have not yet been identified.
There are disagreements within the research community as to whether newts have acquired their regenerative capacity through a unique evolutionary change, or if other animals, including humans, retain this capacity buried somewhere in their genes.
Scientists initially thought that senescent cells couldn’t play a role in regeneration because they could no longer reproduce, says Anthony Atala, a practicing surgeon and bioengineer who leads the Wake Forest Institute for Regenerative Medicine in North Carolina. But Yun’s study points in the other direction. “What this paper shows clearly is that these cells have the potential to be involved in tissue regeneration [in newts]. The question becomes, will these cells be able to do the same in humans.”
As our knowledge of senescent cells increases, Atala thinks we need to embrace a new analogy to help understand them: humans in retirement. They “have acquired a lot of wisdom throughout their whole life and they can help younger people and mentor them to grow to their full potential. We're seeing the same thing with these cells,” he says. They are no longer putting energy into their own reproduction, but the signaling molecules they secrete “can help other cells around them to regenerate.”
There are disagreements within the research community as to whether newts have acquired their regenerative capacity through a unique evolutionary change, or if other animals, including humans, retain this capacity buried somewhere in their genes. If so, it seems that our genes are unable to express this ability, perhaps as part of a tradeoff in acquiring other traits. It is a fertile area of research.
Dedifferentiation is likely to become an important process in the field of regenerative medicine. One extreme example: a lab has been able to turn back the clock and reprogram adult male skin cells into female eggs, a potential milestone in reproductive health. It will be more difficult to control just how far back one wishes to go in the cell's dedifferentiation – part way or all the way back into a stem cell – and then direct it down a different developmental pathway. Yun is optimistic we can learn these tricks from newts.
A growing field of research is using drugs called senolytics to remove senescent cells and slow or even reverse disease of aging.
“Senolytics are great, but senolytics target different types of senescence,” Yun says. “If senescent cells have positive effects in the context of regeneration, of wound healing, then maybe at the beginning of the regeneration process, you may not want to take them out for a little while.”
“If you look at pretty much all biological systems, too little or too much of something can be bad, you have to be in that central zone” and at the proper time, says Atala. “That's true for proteins, sugars, and the drugs that you take. I think the same thing is true for these cells. Why would they be different?”
Our growing understanding that senescence is not a single thing but a variety of things likely means that effective senolytic drugs will not resemble a single sledge hammer but more a carefully manipulated scalpel where some types of senescent cells are removed while others are added. Combinations and timing could be crucial, meaning the difference between regenerating healthy tissue, a scar, or worse.