The Surprising Connection Between Healthy Human Embryos and Treatment-Resistant Cancer

A retrovirus illustration.
Even with groundbreaking advances in cancer treatment and research over the past two centuries, the problem remains that some cancer does not respond to treatment. A subset of patients experience recurrence or metastasis, even when the original tumor is detected at an early stage.
"Why do some tumors evolve into metastatic disease that is then capable of spreading, while other tumors do not?"
Moreover, doctors are not able to tell in advance which patients will respond to treatment and which will not. This means that many patients endure conventional cancer therapies, like countless rounds of chemo and radiation, that do not ultimately increase their likelihood of survival.
Researchers are beginning to understand why some tumors respond to treatment and others do not. The answer appears to lie in the strange connection between human life at its earliest stages — and retroviruses. A retrovirus is different than a regular virus in that its RNA is reverse-transcribed into DNA, which makes it possible for its genetic material to be integrated into a host's genome, and passed on to subsequent generations.
Researchers have shown that reactivation of retroviral sequences is associated with the survival of developing embryos. Certain retroviral sequences must be expressed around the 8-cell stage for successful embryonic development. Active expression of retroviral sequences is required for proper functioning of human embryonic stem cells. These sequences must then shut down at the later state, or the embryo will fail to develop. And here's where things get really interesting: If specific stem cell-associated retroviral sequences become activated again later in life, they seem to play a role in some cancers becoming lethal.
"Eight to 10 million years ago, at the time when we became primates, the population was infected with a virus."
While some retroviral sequences in our genome contribute to the restriction of viral infection and appear to have contributed to the development of the placenta, they can also, if expressed at the wrong time, drive the development of cancer stem cells. Described as the "beating hearts" of treatment-resistant tumors, cancer stem cells are robust and long-living, and they can maintain the ability to proliferate indefinitely.
This apparent connection has inspired Gennadi V. Glinsky, a research scientist at the Institute of Engineering in Medicine at UC San Diego, to find better ways to diagnose and treat metastatic cancer. Glinsky specializes in the development of new technologies, methods, and system integration approaches for personalized genomics-guided prevention and precision therapy of cancer and other common human disorders. We spoke with him about his work and the exciting possibilities it may open up for cancer patients. This interview has been edited and condensed for clarity.
What key questions have driven your research in this area?
I was thinking for years that the major mysteries are: Why do some tumors evolve into metastatic disease that is then capable of spreading, while other tumors do not? What explains some cancer cells' ability to get into the blood or lymph nodes and be able to survive in this very foreign, hostile environment of circulatory channels, and then be able to escape and take root elsewhere in the body?
"If you detect conventional cancer early, and treat it early, it will be cured. But with cancer involving stem cells, even if you diagnose it early, it will come back."
When we were able to do genomic analysis on enough early stage cancers, we arrived at an alternative concept of cancer that starts in the stem cells. Stem cells exist throughout our bodies, so in the case of cancer starting in stem cells you will have metastatic properties … because that's what stem cells do. They can travel throughout the body, they can make any other type of cell or resemble them.
So there are basically two types of cancer: conventional non-stem cell cancer and stem cell-like cancer. If you detect conventional cancer early, and treat it early, it will be cured. But with cancer involving stem cells, even if you diagnose it early, it will come back.
What causes some cancer to originate in stem cells?
Cancer stem cells possess stemness [or the ability to self-renew, differentiate, and survive chemical and physical insults]. Stemness is driven by the reactivation of retroviral sequences that have been integrated into the human genome.
Tell me about these retroviral sequences.
Eight to 10 million years ago, at the time when we became primates, the population was infected with a virus. Part of the population survived and the virus was integrated into our primate ancestors' genome. These are known as human endogenous retroviruses, or HERVs. The DNA of the host cells became carriers of these retroviral sequences, and whenever the host cells multiply, they carry the sequences in them and pass them on to future generations.
This pattern of infection and integration of retroviral sequences has happened thousands of times during our evolutionary history. As a result, eight percent of the human genome is derived from these different retroviral sequences.
We've found that some HERVs are expressed in some cancers. For example, 10-15 percent of prostate cancer is stem cell-like. But at first it was not understood what this HERV expression meant.
Gennadi V. Glinsky, a research scientist at the Institute of Engineering in Medicine at UC San Diego.
(Courtesy)
How have you endeavored to solve this in your lab?
We were trying to track down metastatic prostate cancer. We found a molecular signature of prostate cancer that made the prostate tumors look like stem cells. And those were the ones likely to fail cancer therapy. Then we applied this signature to other types of cancers and we found that uniformly, tumors that exhibit stemness fail therapy.
Then in 2014, several breakthrough papers came out that linked the activation of the retroviral sequences in human embryonic stem cells and in human embryo development. When I read these papers, it occurred to me that if these retroviral sequences are required for pluripotency in human embryonic stem cells, they must be involved in stem cell-resembling human cancer that's likely to fail therapy.
What was one of the biggest aha moments in your cancer research?
Several major labs around the U.S. took advantage of The Cancer Genome Anatomy Project, which made it possible to have access to about 12,000 individual human tumors across a spectrum of 30 or so cancer types. This is the largest set of tumors that's ever been made available in a comprehensive and state of the art way. So we now know all there is to know about the genetics of these tumors, including the long-term clinical outcome.
"When we cross-referenced these 10,713 human cancer survival genes to see how many are part of the retroviral network in human cells, we found that the answer was 97 percent!"
These labs identified 10,713 human genes that were associated with the likelihood of patients surviving or dying after [cancer] treatment. I call them the human cancer survival genes, and there are two classes of them: one whose high expression in tumors correlates with an increased likelihood of survival and one whose high expression in tumors correlates with a decreased likelihood of survival.
When we cross-referenced these 10,713 human cancer survival genes to see how many are part of the retroviral network in human cells, we found that the answer was 97 percent!
How will all of this new knowledge change how cancer is treated?
To make cancer stem cells vulnerable to treatment, you need to interfere with stemness and the stemness network. And to do this, you would need to identify the retroviral component of the network, and interfere with this component therapeutically.
The real breakthrough will come when we start to treat these early stage stem cell-like cancers with stem cell-targeting therapy that we are trying to develop. And with our ability to detect the retroviral genome activation, we will be able to detect stem cell-like cancer very early on.
How far away are we from being able to apply this information clinically?
We have two molecule [treatment] candidates. We know that they efficiently interfere with the stemness program in the cells. The road to clinical trials is typically a long one, but since we're clear about our targets, it's a shorter road. We would like to say it's two to three years until we can start a human trial.
Chris Mirabile sprints on a track in Sarasota, Florida, during his daily morning workout. He claims to be a superager already, at age 38, with test results to back it up.
Earlier this year, Harvard scientists reported that they used an anti-aging therapy to reverse blindness in elderly mice. Several other studies in the past decade have suggested that the aging process can be modified, at least in lab organisms. Considering mice and humans share virtually the same genetic makeup, what does the rodent-based study mean for the humans?
In truth, we don’t know. Maybe nothing.
What we do know, however, is that a growing number of people are dedicating themselves to defying the aging process, to turning back the clock – the biological clock, that is. Take Bryan Johnson, a man who is less mouse than human guinea pig. A very wealthy guinea pig.
The 45-year-old venture capitalist spends over $2 million per year reversing his biological clock. To do this, he employs a team of 30 medical doctors and other scientists. His goal is to eventually reset his biological clock to age 18, and “have all of his major organs — including his brain, liver, kidneys, teeth, skin, hair, penis and rectum — functioning as they were in his late teens,” according to a story earlier this year in the New York Post.
But his daily routine paints a picture that is far from appealing: for example, rigorously adhering to a sleep schedule of 8 p.m. to 5 a.m. and consuming more than 100 pills and precisely 1,977 calories daily. Considering all of Johnson’s sacrifices, one discovers a paradox:
To live forever, he must die a little every day until he reaches his goal - if he ever reaches his goal.
Less extreme examples seem more helpful for people interested in happy, healthy aging. Enter Chris Mirabile, a New Yorker who says on his website, SlowMyAge.com, that he successfully reversed his biological age by 13.6 years, from the chronological age of 37.2 to a biological age of 23.6. To put this achievement in perspective, Johnson, to date, has reversed his biological clock by 2.5 years.
Mirabile's habits and overall quest to turn back the clock trace back to a harrowing experience at age 16 during a school trip to Manhattan, when he woke up on the floor with his shirt soaked in blood.
Mirabile, who is now 38, supports his claim with blood tests that purport to measure biological age by assessing changes to a person’s epigenome, or the chemical marks that affect how genes are expressed. Mirabile’s tests have been run and verified independently by the same scientific lab that analyzes Johnson’s. (In an email to Leaps.org, the lab, TruDiagnostic, confirmed Mirabile’s claims about his test results.)
There is considerable uncertainty among scientists about the extent to which these tests can accurately measure biological age in individuals. Even so, Mirabile’s results are intriguing. They could reflect his smart lifestyle for healthy aging.
His habits and overall quest to turn back the clock trace back to a harrowing experience at age 16 during a school trip to Manhattan, when Mirabile woke up on the floor with his shirt soaked in blood. He’d severed his tongue after a seizure. He later learned it was caused by a tumor the size of a golf ball. As a result, “I found myself contemplating my life, what I had yet to experience, and mortality – a theme that stuck with me during my year of recovery and beyond,” Mirabile told me.
For the next 15 years, he researched health and biology, integrating his learnings into his lifestyle. Then, in his early 30s, he came across an article in the journal Cell, "The Hallmarks of Aging," that outlined nine mechanisms of the body that define the aging process. Although the paper says there are no known interventions to delay some of these mechanisms, others, such as inflammation, struck Mirabile as actionable. Reading the paper was his “moment of epiphany” when it came to the areas where he could assert control to maximize his longevity.
He also wanted “to create a resource that my family, friends, and community could benefit from in the short term,” he said. He turned this knowledge base into a company called NOVOS dedicated to extending lifespan.
His longevity advice is more accessible than Johnson’s multi-million dollar approach, as Mirabile spends a fraction of that amount. Mirabile takes one epigenetic test per year and has a gym membership at $45 per month. Unlike Johnson, who takes 100 pills per day, Mirabile takes 10, costing another $45 monthly, including a B-complex, fish oil, Vitamins D3 and K2, and two different multivitamin supplements.
Mirabile’s methods may be easier to apply in other ways as well, since they include activities that many people enjoy anyway. He’s passionate about outdoor activities, travels frequently, and has loving relationships with friends and family, including his girlfriend and collie.
Here are a few of daily routines that could, he thinks, contribute to his impressively young bio age:
After waking at 7:45 am, he immediately drinks 16 ounces of water, with 1/4 teaspoon of sodium and potassium to replenish electrolytes. He takes his morning vitamins, brushes and flosses his teeth, puts on a facial moisturizing sunblock and goes for a brisk, two-mile walk in the sun. At 8:30 am on Mondays, Wednesdays, and Fridays he lift weights, focusing on strength and power, especially in large muscle groups.
Tuesdays, Thursdays and Saturdays are intense cardio days. He runs 5-7 miles or bicycles for 60 minutes first thing in the morning at a brisk pace, listening to podcasts. Sunday morning cardio is more leisurely.
After working out each day, he’s back home at 9:20 am, where he makes black coffee, showers, then applies serum and moisturizing sunblock to his face. He works for about three hours on his laptop, then has a protein shake and fruit.
Mirabile is a dedicated intermittent faster, with a six hour eating window in between 18 hours fasts. At 3 pm, he has lunch. The Mediterranean lineup often features salmon, sardines, olive oil, pink Himalayan salt plus potassium salt for balance, and lots of dried herbs and spices. He almost always finishes with 1/3 to 1/2 bar of dark chocolate.
If you are what you eat, Mirabile is made of mostly plants and lean meats. He follows a Mediterranean diet full of vegetables, fruits, fatty fish and other meats full of protein and unsaturated fats. “These may cost more than a meal at an American fast-food joint, but then again, not by much,” he said. Each day, he spends $25 on all his meals combined.
At 6 pm, he takes the dog out for a two-mile walk, taking calls for work or from family members along the way. At 7 pm, he dines with his girlfriend. Like lunch, this meal is heavy on widely available ingredients, including fish, fresh garlic, and fermented food like kimchi. Mirabile finishes this meal with sweets, like coconut milk yogurt with cinnamon and clove, some stevia, a mix of fresh berries and cacao nibs.
If Mirabile's epigenetic tests are accurate, his young biological age could be thanks to his healthy lifestyle, or it could come from a stroke of luck if he inherited genes that protect against aging.
At 8 pm, he wraps up work duties and watches shows with his girlfriend, applies serum and moisturizer yet again, and then meditates with the lights off. This wind-down, he said, improves his sleep quality. Wearing a sleep mask and earplugs, he’s asleep by about 10:30.
“I’ve achieved stellar health outcomes, even after having had the physiological stressors of a brain tumor, without spending a fortune,” Mirabile said. “In fact, even during times when I wasn’t making much money as a startup founder with few savings, I still managed to live a very healthy, pro-longevity lifestyle on a modest budget.”
Mirabile said living a cleaner, healthier existence is a reality that many readers can achieve. It’s certainly true that many people live in food deserts and have limited time for exercise or no access to gyms, but James R. Doty, a clinical professor of neurosurgery at Stanford, thinks many can take more action to stack the odds that they’ll “be happy and live longer.” Many of his recommendations echo aspects of Mirabile’s lifestyle.
Each night, Doty said, it’s vital to get anywhere between 6-8 hours of good quality sleep. Those who sleep less than 6 hours per night are at an increased risk of developing a whole host of medical problems, including high blood pressure, type 2 diabetes, and stroke.
In addition, it’s critical to follow Mirabile’s prescription of exercise for about one hour each day, and intensity levels matter. Doty noted that, in 2017, researchers at Brigham Young University found that people who ran at a fast pace for 30-40 minutes five days per week were, on average, biologically younger by nine years, compared to those who subscribed to more moderate exercise programs, as well as those who rarely exercised.
When it comes to nutrition, one should consider fasting for 16 hours per day, Doty said. This is known as the 16/8 method, where one’s daily calories are consumed within an eight hour window, fasting for the remaining 16 hours, just like Mirabile. Intermittent fasting is associated with cellular repair and less inflammation, though it’s not for everyone, Doty added. Consult with a medical professional before trying a fasting regimen.
Finally, Doty advised to “avoid anger, avoid stress.” Easier said than done, but not impossible. “Between stimulus and response, there is a pause and within that pause lies your freedom,” Doty said. Mirabile’s daily meditation ritual could be key to lower stress for healthy aging. Research has linked regular, long-term meditation to having a lower epigenetic age, compared to control groups.
Many other factors could apply. Having a life purpose, as Mirabile does with his company, has also been associated with healthy aging and lower epigenetic age. Of course, Mirabile is just one person, so it’s hard to know how his experience will apply to others. If his tests are accurate, his young biological age could be thanks to his healthy lifestyle, or it could come from a stroke of luck if he inherited genes that protect against aging. Clearly, though, any such genes did not protect him from cancer at an early age.
The third and perhaps most likely explanation: Mirabile’s very young biological age results from a combination of these factors. Some research shows that genetics account for only 25 percent of longevity. That means environmental factors could be driving the other 75 percent, such as where you live, frequency of exercise, quality of nutrition and social support.
The middle-aged – even Brian Johnson – probably can’t ever be 18 again. But more modest goals are reasonable for many. Control what you can for a longer, healthier life.
FDA, researchers work to make clinical trials more diverse
The U.S. population is becoming more diverse, but clinical trials don't reflect that, experts say. Some are focusing on recruiting minorities to participate in research.
Nestled in a predominately Hispanic neighborhood, a new mural outside Guadalupe Centers Middle School in Kansas City, Missouri imparts a powerful message: “Clinical Research Needs Representation.” The colorful portraits painted above those words feature four cancer survivors of different racial and ethnic backgrounds. Two individuals identify as Hispanic, one as African American and another as Native American.
One of the patients depicted in the mural is Kim Jones, a 51-year-old African American breast cancer survivor since 2012. She advocated for an African American friend who participated in several clinical trials for ovarian cancer. Her friend was diagnosed in an advanced stage at age 26 but lived nine more years, thanks to the trials testing new therapeutics. “They are definitely giving people a longer, extended life and a better quality of life,” said Jones, who owns a nail salon. And that’s the message the mural aims to send to the community: Clinical trials need diverse participants.
While racial and ethnic minority groups represent almost half of the U.S. population, the lack of diversity in clinical trials poses serious challenges. Limited awareness and access impede equitable representation, which is necessary to prove the safety and effectiveness of medical interventions across different groups.
A Yale University study on clinical trial diversity published last year in BMJ Medicine found that while 81 percent of trials testing the new cancer drugs approved by the U.S. Food and Drug Administration between 2012 and 2017 included women, only 23 percent included older adults and 5 percent fairly included racial and ethnic minorities. “It’s both a public health and social justice issue,” said Jennifer E. Miller, an associate professor of medicine at Yale School of Medicine. “We need to know how medicines and vaccines work for all clinically distinct groups, not just healthy young White males.” A recent JAMA Oncology editorial stresses out the need for legislation that would require diversity action plans for certain types of trials.
Ensuring meaningful representation of racial and ethnic minorities in clinical trials for regulated medical products is fundamental to public health.--FDA Commissioner Robert M. Califf.
But change is on the horizon. Last April, the FDA issued a new draft guidance encouraging industry to find ways to revamp recruitment into clinical trials. The announcement, which expanded on previous efforts, called for including more participants from underrepresented racial and ethnic segments of the population.
“The U.S. population has become increasingly diverse, and ensuring meaningful representation of racial and ethnic minorities in clinical trials for regulated medical products is fundamental to public health,” FDA commissioner Robert M. Califf, a physician, said in a statement. “Going forward, achieving greater diversity will be a key focus throughout the FDA to facilitate the development of better treatments and better ways to fight diseases that often disproportionately impact diverse communities. This guidance also further demonstrates how we support the Administration’s Cancer Moonshot goal of addressing inequities in cancer care, helping to ensure that every community in America has access to cutting-edge cancer diagnostics, therapeutics and clinical trials.”
Lola Fashoyin-Aje, associate director for Science and Policy to Address Disparities in the Oncology Center of Excellence at the FDA, said that the agency “has long held the view that clinical trial participants should reflect the clinical and demographic characteristics of the patients who will ultimately receive the drug once approved.” However, “numerous studies over many decades” have measured the extent of underrepresentation. One FDA analysis found that the proportion of White patients enrolled in U.S. clinical trials (88 percent) is much higher than their numbers in country's population. Meanwhile, the enrollment of African American and Native Hawaiian/American Indian and Alaskan Native patients is below their national numbers.
The FDA’s guidance is accelerating researchers’ efforts to be more inclusive of diverse groups in clinical trials, said Joyce Sackey, a clinical professor of medicine and associate dean at Stanford School of Medicine. Underrepresentation is “a huge issue,” she noted. Sackey is focusing on this in her role as the inaugural chief equity, diversity and inclusion officer at Stanford Medicine, which encompasses the medical school and two hospitals.
Until the early 1990s, Sackey pointed out, clinical trials were based on research that mainly included men, as investigators were concerned that women could become pregnant, which would affect the results. This has led to some unfortunate consequences, such as indications and dosages for drugs that cause more side effects in women due to biological differences. “We’ve made some progress in including women, but we have a long way to go in including people of different ethnic and racial groups,” she said.
A new mural outside Guadalupe Centers Middle School in Kansas City, Missouri, advocates for increasing diversity in clinical trials. Kim Jones, 51-year-old African American breast cancer survivor, is second on the left.
Artwork by Vania Soto. Photo by Megan Peters.
Among racial and ethnic minorities, distrust of clinical trials is deeply rooted in a history of medical racism. A prime example is the Tuskegee Study, a syphilis research experiment that started in 1932 and spanned 40 years, involving hundreds of Black men with low incomes without their informed consent. They were lured with inducements of free meals, health care and burial stipends to participate in the study undertaken by the U.S. Public Health Service and the Tuskegee Institute in Alabama.
By 1947, scientists had figured out that they could provide penicillin to help patients with syphilis, but leaders of the Tuskegee research failed to offer penicillin to their participants throughout the rest of the study, which lasted until 1972.
Opeyemi Olabisi, an assistant professor of medicine at Duke University Medical Center, aims to increase the participation of African Americans in clinical research. As a nephrologist and researcher, he is the principal investigator of a clinical trial focusing on the high rate of kidney disease fueled by two genetic variants of the apolipoprotein L1 (APOL1) gene in people of recent African ancestry. Individuals of this background are four times more likely to develop kidney failure than European Americans, with these two variants accounting for much of the excess risk, Olabisi noted.
The trial is part of an initiative, CARE and JUSTICE for APOL1-Mediated Kidney Disease, through which Olabisi hopes to diversify study participants. “We seek ways to engage African Americans by meeting folks in the community, providing accessible information and addressing structural hindrances that prevent them from participating in clinical trials,” Olabisi said. The researchers go to churches and community organizations to enroll people who do not visit academic medical centers, which typically lead clinical trials. Since last fall, the initiative has screened more than 250 African Americans in North Carolina for the genetic variants, he said.
Other key efforts are underway. “Breaking down barriers, including addressing access, awareness, discrimination and racism, and workforce diversity, are pivotal to increasing clinical trial participation in racial and ethnic minority groups,” said Joshua J. Joseph, assistant professor of medicine at the Ohio State University Wexner Medical Center. Along with the university’s colleges of medicine and nursing, researchers at the medical center partnered with the African American Male Wellness Agency, Genentech and Pfizer to host webinars soliciting solutions from almost 450 community members, civic representatives, health care providers, government organizations and biotechnology professionals in 25 states and five countries.
Their findings, published in February in the journal PLOS One, suggested that including incentives or compensation as part of the research budget at the institutional level may help resolve some issues that hinder racial and ethnic minorities from participating in clinical trials. Compared to other groups, more Blacks and Hispanics have jobs in service, production and transportation, the authors note. It can be difficult to get paid leave in these sectors, so employees often can’t join clinical trials during regular business hours. If more leaders of trials offer money for participating, that could make a difference.
Obstacles include geographic access, language and other communications issues, limited awareness of research options, cost and lack of trust.
Christopher Corsico, senior vice president of development at GSK, formerly GlaxoSmithKline, said the pharmaceutical company conducted a 17-year retrospective study on U.S. clinical trial diversity. “We are using epidemiology and patients most impacted by a particular disease as the foundation for all our enrollment guidance, including study diversity plans,” Corsico said. “We are also sharing our results and ideas across the pharmaceutical industry.”
Judy Sewards, vice president and head of clinical trial experience at Pfizer’s headquarters in New York, said the company has committed to achieving racially and ethnically diverse participation at or above U.S. census or disease prevalence levels (as appropriate) in all trials. “Today, barriers to clinical trial participation persist,” Sewards said. She noted that these obstacles include geographic access, language and other communications issues, limited awareness of research options, cost and lack of trust. “Addressing these challenges takes a village. All stakeholders must come together and work collaboratively to increase diversity in clinical trials.”
It takes a village indeed. Hope Krebill, executive director of the Masonic Cancer Alliance, the outreach network of the University of Kansas Cancer Center in Kansas City, which commissioned the mural, understood that well. So her team actively worked with their metaphorical “village.” “We partnered with the community to understand their concerns, knowledge and attitudes toward clinical trials and research,” said Krebill. “With that information, we created a clinical trials video and a social media campaign, and finally, the mural to encourage people to consider clinical trials as an option for care.”
Besides its encouraging imagery, the mural will also be informational. It will include a QR code that viewers can scan to find relevant clinical trials in their location, said Vania Soto, a Mexican artist who completed the rendition in late February. “I’m so honored to paint people that are survivors and are living proof that clinical trials worked for them,” she said.
Jones, the cancer survivor depicted in the mural, hopes the image will prompt people to feel more open to partaking in clinical trials. “Hopefully, it will encourage people to inquire about what they can do — how they can participate,” she said.