leukemia
Body-on-a-Chip Device Predicts Cancer Drug Responses
Posted on by Dr. Francis Collins
Researchers continue to produce impressive miniature human tissues that resemble the structure of a range of human organs, including the livers, kidneys, hearts, and even the brain. In fact, some researchers are now building on this success to take the next big technological step: placing key components of several miniature organs on a chip at once.
These body-on-a-chip (BOC) devices place each tissue type in its own pea-sized chamber and connect them via fluid-filled microchannels into living, integrated biological systems on a laboratory plate. In the photo above, the BOC chip is filled with green fluid to make it easier to see the various chambers. For example, this easy-to-reconfigure system can make it possible to culture liver cells (chamber 1) along with two cancer cell lines (chambers 3, 5) and cardiac function chips (chambers 2, 4).
Researchers circulate blood-mimicking fluid through the chip, along with chemotherapy drugs. This allows them to test the agents’ potential to fight human cancer cells, while simultaneously gathering evidence for potential adverse effects on tissues placed in the other chambers.
This BOC comes from a team of NIH-supported researchers, including James Hickman and Christopher McAleer, Hesperos Inc., Orlando, FL. The two were challenged by their Swiss colleagues at Roche Pharmaceuticals to create a leukemia-on-a-chip model. The challenge was to see whether it was possible to reproduce on the chip the known effects and toxicities of diclofenac and imatinib in people.
As published in Science Translational Medicine, they more than met the challenge. The researchers showed as expected that imatinib did not harm liver cells [1]. But, when treated with diclofenac, liver cells on the chip were reduced in number by about 30 percent, an observation consistent with the drug’s known liver toxicity profile.
As a second and more challenging test, the researchers reconfigured the BOC by placing a multi-drug resistant vulva cancer cell line in one chamber and, in another, a breast cancer cell line that responded to drug treatment. To explore side effects, the system also incorporated a chamber with human liver cells and two others containing beating human heart cells, along with devices to measure the cells’ electrical and mechanical activity separately.
These studies showed that tamoxifen, commonly used to treat breast cancer, indeed killed a significant number of the breast cancer cells on the BOC. But, it only did so after liver cells on the chip processed the tamoxifen to produce its more active metabolite!
Meanwhile, tamoxifen alone didn’t affect the drug-resistant vulva cancer cells on the chip, whether or not liver cells were present. This type of cancer cell has previously been shown to pump the drug out through a specific channel. Studies on the chip showed that this form of drug resistance could be overcome by adding a second drug called verapamil, which blocks the channel.
Both tamoxifen alone and the combination treatment showed some off-target effects on heart cells. While the heart cells survived the treatment, they contracted more slowly and with less force. The encouraging news was that the heart cells bounced back from the tamoxifen-only treatment within three days. But when the drug-drug combination was tested, the cardiac cells did not recover their function during the same time period.
What makes advances like this especially important is that only 1 in 10 drug candidates entering human clinical trials ultimately receives approval from the Food and Drug Administration (FDA) [2]. Often, drug candidates fail because they prove toxic to the human brain, liver, kidneys, or other organs in ways that preclinical studies in animals didn’t predict.
As BOCs are put to work in testing new drug candidates and especially treatment combinations, the hope is that we can do a better job of predicting early on which chemical compounds will prove safe and effective in humans. For those drug candidates that are ultimately doomed, “failing early” is key to reducing drug development costs. By culturing an individual patient’s cells in the chambers, BOCs also may be used to help doctors select the best treatment option for that particular patient. The ultimate goal is to accelerate the translation of basic discoveries into clinical breakthroughs. For more information about tissue chips, take a look at NIH’s Tissue Chip for Drug Screening program.
References:
[1] Multi-organ system for the evaluation of efficacy and off-target toxicity of anticancer therapeutics. McAleer CW, Long CJ, Elbrecht D, Sasserath T, Bridges LR, Rumsey JW, Martin C, Schnepper M, Wang Y, Schuler F, Roth AB, Funk C, Shuler ML, Hickman JJ. Sci Transl Med. 2019 Jun 19;11(497).
[2] Clinical development success rates for investigational drugs. Hay M, Thomas DW, Craighead JL, Economides C, Rosenthal J. Nat Biotechnol. 2014 Jan;32(1):40-51.
Links:
Tissue Chip for Drug Screening (National Center for Advancing Translational Sciences/NIH)
James Hickman (Hesperos, Inc., Orlando, FL)
NIH Support: National Center for Advancing Translational Sciences
A Scientist Who Bends Musical Notes
Posted on by Dr. Francis Collins
As a pioneer in cancer immunotherapy, Jim Allison has spent decades tackling major scientific challenges. So it’s interesting that Allison would consider one of the top five moments in his life jamming onstage with country star Willie Nelson. Yes, in addition to being a top-flight scientist at the University of Texas MD Anderson Cancer Center, Houston, Allison plays a mean harmonica.
Allison taught himself how to bend notes on the harmonica as a teenager growing up in a small Texas town. By his 20s, Allison was good enough to jam a couple of nights a week with the now legendary Clay Blaker & the Texas Honky Tonk Band. When Blaker asked if he wanted to hit the road with the band, Allison declined. He had his postdoctoral training to finish in molecular immunology.
FDA Approves First CAR-T Cell Therapy for Pediatric Acute Lymphoblastic Leukemia
Posted on by Dr. Francis Collins
Caption: Cancer survivor Emily Whitehead with her dog Lucy.
Credit: Emily Whitehead Foundation
Tremendous progress continues to be made against the Emperor of All Maladies, cancer. One of the most exciting areas of progress involves immunotherapy, a treatment strategy that harnesses the natural ability of the body’s own immune cells to attack and kill tumor cells. A lot of extremely hard work has gone into this research, so I was thrilled to learn that the Food and Drug Administration (FDA) just announced today its first approval of a promising type of immunotherapy called CAR-T cell therapy for kids and young adults with B-cell acute lymphoblastic leukemia (ALL)—the most common childhood cancer in the U.S.
ALL is a cancer of white blood cells called lymphocytes. Its treatment with chemotherapy drugs, developed with NIH support, has transformed ALL’s prognosis in kids from often fatal to largely treatable: about 90 percent of young patients now recover. But for those for whom the treatment fails, the prognosis is grim.
In the spring of 2012, Emily Whitehead of Philipsburg, PA was one such patient. The little girl was deathly ill, and her parents were worried they’d run out of options. That’s when doctors at Children’s Hospital of Philadelphia gave Emily and her parents new hope. Carl June and his team had successfully treated three adults with their version of CAR-T cell therapy, which is grounded in initial basic research supported by NIH [1,2]. Moving forward with additional clinical tests, they treated Emily—their first pediatric patient—that April. For a while, it was touch and go, and Emily almost died. But by May 2012, her cancer was in remission. Today, five years later, 12-year-old Emily remains cancer free and is thriving. And I’ve had the great privilege of getting to know Emily and her parents over the last few years.
Regenerative Medicine: Making Blood Stem Cells in the Lab
Posted on by Dr. Francis Collins
Caption: Arrow in first panel points to an endothelial cell induced to become hematopoietic stem cell (HSC). Second and third panels show the expansion of HSCs over time.
Credit: Raphael Lis, Weill Cornell Medicine, New York, NY
Bone marrow transplants offer a way to cure leukemia, sickle cell disease, and a variety of other life-threatening blood disorders.There are two major problems, however: One is many patients don’t have a well-matched donor to provide the marrow needed to reconstitute their blood with healthy cells. Another is even with a well-matched donor, rejection or graft versus host disease can occur, and lifelong immunosuppression may be needed.
A much more powerful option would be to develop a means for every patient to serve as their own bone marrow donor. To address this challenge, researchers have been trying to develop reliable, lab-based methods for making the vital, blood-producing component of bone marrow: hematopoietic stem cells (HSCs).
Two new studies by NIH-funded research teams bring us closer to achieving this feat. In the first study, researchers developed a biochemical “recipe” to produce HSC-like cells from human induced pluripotent stem cells (iPSCs), which were derived from mature skin cells. In the second, researchers employed another approach to convert mature mouse endothelial cells, which line the inside of blood vessels, directly into self-renewing HSCs. When these HSCs were transplanted into mice, they fully reconstituted the animals’ blood systems with healthy red and white blood cells.
