This is another approach to the liquid biopsy that clinical laboratories and pathologists may use to detect cancer less invasively
Screening for cancer usually involves invasive, often painful, costly biopsies to provide samples for diagnostic clinical laboratory testing. But now, scientists at the University of Technology (UTS) in Sydney, Australia, have developed a novel approach to identifying tumorous cells in the bloodstream that uses imaging to cause cells with elevated lactase to fluoresce, according to a UTS news release.
The UTS researchers created a Static Droplet Microfluidic (SDM) device that detects circulating tumor cells (CTC) that have separated from the cancer source and entered the bloodstream. The isolation of CTCs is an intrinsic principle behind liquid biopsies, and microfluidic gadgets can improve the efficiency in which problematic cells are captured.
The University of Technology’s new SDM device could lead the way for very early detection of cancers and help medical professionals monitor and treat cancers.
“Managing cancer through the assessment of tumor cells in blood samples is far less invasive than taking tissue biopsies. It allows doctors to do repeat tests and monitor a patient’s response to treatment,” explained Majid E. Warkiani, PhD, Professor, School of Biomedical Engineering, UTS, and one of the authors of the study, in a news release. Clinical laboratories and pathologists may soon have a new liquid biopsy approach to detecting cancers. (Photo copyright: University of New South Wales.)
Precision Medicine a Goal of UTS Research
The University of Technology’s new SDM device differentiates tumor cells from normal cells using a unique metabolic signature of cancer that involves the waste product lactate.
“A single tumor cell can exist among billions of blood cells in just one milliliter of blood, making it very difficult to find,” explained Majid E. Warkiani, PhD, a professor in the School of Biomedical Engineering at UTS and one of the authors of the study, in the news release.
“The new [SDM] detection technology has 38,400 chambers capable of isolating and classifying the number of metabolically active tumor cells,” he added.
“In the 1920s, Otto Warburg discovered that cancer cells consume a lot of glucose and so produce more lactate. Our device monitors single cells for increased lactate using pH sensitive fluorescent dyes that detect acidification around cells,” Warkiani noted.
After the SDM device has detected the presence of questionable cells, those cells undergo further genetic testing and molecular analysis to determine the source of the cancer. Because circulating tumor cells are a precursor of metastasis, the device’s ability to identify CTCs in very small quantities can aid in the diagnosis and classification of the cancer and the establishment of personalized treatment plans, a key goal of precision medicine.
The new technology was also designed to be operated easily by medical personnel without the need for high-end equipment and tedious, lengthy training sessions. This feature should allow for easier integration into medical research, clinical laboratory diagnostics, and enable physicians to monitor cancer patients in a functional and inexpensive manner, according to the published study.
“Managing cancer through the assessment of tumor cells in blood samples is far less invasive than taking tissue biopsies. It allows doctors to do repeat tests and monitor a patient’s response to treatment,” stated Warkiani in the press release.
The team have filed for a provisional patent for the device and plan on releasing it commercially in the future.
Other Breakthroughs in MCED Testing
Scientists around the world have been working to develop a simple blood test for diagnosing cancer and creating optimal treatment protocols for a long time. There have been some notable breakthroughs in the advancement of multi-cancer early detection (MCED) tests, which Dark Daily has covered in prior ebriefings.
According to the Centers for Disease Control and Prevention (CDC), cancer ranks second in the leading causes of death in the US, just behind heart disease. There were 1,603,844 new cancer cases reported in 2020, and 602,347 people died of various cancers that year in the US.
According to the National Cancer Institute, the most common cancers diagnosed in the US annually include:
Cancer is a force in Australia as well. It’s estimated that 151,000 Australians were diagnosed with cancer in 2021, and that nearly one in two Australians will receive a diagnosis of the illness by the age of 85, according to Cancer Council South Australia.
The population of Australia in 2021 was 25.69 million, compared to the US in the same year at 331.9 million.
The development of the University of Technology’s static droplet microfluidic device is another approach in the use of liquid biopsies as a means to detect cancer less invasively.
More research and clinical studies are needed before the device can be ready for clinical use by anatomic pathology groups and medical laboratories, but its creation may lead to faster diagnosis of cancers, especially in the early stages, which could lead to improved patient outcomes.
The researchers unveiled a diagnostic device that uses microfluidic technology to identify cell types in blood by their size. The device also “can isolate individual cancer cells from patient blood samples,” according to a news release.
The ability to isolate circulating tumor cells could enable clinical laboratories to perform diagnostic cancer tests on liquid biopsies and blood samples. Dark Daily reported on various studies involving liquid biopsies—an alternative to invasive and costly cancer diagnostic procedures, such as surgery and tissue biopsies—in previous e-briefings.
“This new microfluidics chip lets us separate cancer cells from whole blood or minimally diluted blood. Our device is cheap and doesn’t require much specimen preparation or dilution, making it fast and easy-to-use,” said Ian Papautsky, PhD, Professor of Bioengineering at University of Illinois at Chicago, in the news release. He is shown above with members of the Papautsky Lab, which has been developing “microfluidic systems and point- of-care sensors for public health applications.” (Photo copyright: University of Illinois at Chicago.)
Searching for ‘Purity’
The UIC and QUT researchers were motivated by the
information-rich nature of circulating tumor cells. They also saw opportunity
for escalated “purity” in results, as compared to past studies.
In the paper, they acknowledged the work of other scientists
who deployed microfluidic technology affinity-based methods to differentiate
tumor cells in blood. Past studies (including previous work by the authors)
also explored tumor cells based on size and difference from white blood cells.
“While many emerging systems have been tested using patient samples, they share a common shortcoming: their purity remains to be significantly improved. High purity is in strong demand for circulating tumor cell enumeration, molecular characterization, and functional assays with less background intervention from white blood cells,” the authors wrote in their paper.
How the Device Works
The scientists say their system leverages “size-dependent
inertial migration” of cells. According to the news release:
Blood passes through “microchannels” formed in
plastic in the device;
“Inertial migration and shear-induced diffusion”
separate cancer cells from blood;
Tiny differences in size determine a cell’s
attraction to a location; and
Cells separate to column locations as the liquid
moves.
In other words, the device works as a filter sorting out, in
blood samples, the circulating tumor cells based on their unique size, New
Atlas explained.
93% of Cancer Cells Recovered by Device
When the researchers tested their new device:
Researchers placed 10 small-cell-lung cancer cells into five-milliliter samples of healthy blood;
The blood was then flowed through the device; and
93% of the cancer cells were recovered.
“A 7.5 milliliter tube of blood, which is typical volume for
a blood draw, might have 10 cancer cells and 35- to 40-billion blood cells. So,
we are really looking for a needle in a haystack,” Papautsky stated in the news
release.
The graphic above illustrates how, in the lab, the microfluidic device enabled the researchers to separate out cancer cells in six of the eight lung cancer samples they studied. (Graphic copyright: Ian Papautsky, PhD/University of Illinois at Chicago/New Atlas.)
“We report on a novel multi-flow microfluidic system for the
separation of circulating tumor cells with high purity. The microchannel takes
advantage of inertial migration of cells. The lateral migration of cells
strongly depends on cell size in our microchannel, and label-free separation of
circulating tumor cells from white blood cells is thus achieved without
sophisticated sample predation steps and external controls required by
affinity-based and active approaches,” the researchers wrote in their paper.
The researchers plan wider trials and the addition of
biomarkers to enable cancer DNA detection, New Atlas reported, which described
the UIC/QUT study as part of a “new wave of diagnostics.”
With so much focus on liquid biopsy research, it may be
possible for medical laboratories to one day not only diagnose cancer through
blood tests, but also to find the disease earlier and in a more precise way
than with traditional tissue sample analysis.
Using GPIIb/IIIa inhibition, and ion chelation, researchers have developed a “universal” method for preserving blood up to 72 hours while keeping it viable for advanced rare-cell applications
However, preserving sample quality is an essential part of analytical accuracy. This is particularly true in precision oncology and other specialties where isolating rare cells (aka, low abundance cells), such as circulating tumor cells (CTCs), is a key component to obtaining information and running diagnostics.
Should further testing validate their findings and methodology, this change could allow greater use of central laboratories and other remote testing facilities that previously would not be available due to distance and sample travel time.
Keeping Blood Alive Is Not Easy
“At Mass. General, we have the luxury of being so integrated with the clinical team that we can process blood specimens in the lab typically within an hour or two after they are drawn,” stated lead author Keith Wong, PhD, former Research Fellow, MGH-CEM, and now Senior Scientist at Rubius Therapeutics, Boston, in a Mass General press release. “But to make these liquid biopsy technologies routine lab tests for the rest of the world, we need ways to keep blood alive for much longer than several hours, since these assays are best performed in central laboratories for reasons of cost-effectiveness and reproducibility.”
Study authors Wong and co-lead author Shannon Tessier, PhD, Investigator at MGH-CEM, noted that current FDA-approved blood stabilization methods for CTC assays use chemical fixation—a process that can result in degradation of sensitive biomolecules and kill the cells within the sample.
Without stabilization, however, breakdown of red cells, activation of leukocytes (white blood cells), and clot formation can render the results of analyzing a sample useless, or create issues with increasingly sensitive equipment used to run assays and diagnostics.
“We wanted to slow down the biological clock as much as possible by using hypothermia, but that is not as simple as it sounds,” says Tessier. “Low temperature is a powerful means to decrease metabolism, but a host of unwanted side effects occur at the same time.”
Researchers started by using hypothermic treatments to slow degradation and cell death. However, this created another obstacle—aggressive platelet coagulation. By introducing glycoprotein IIb/IIIa inhibitors, they found they could minimize this aggregation.
Keith Wong, PhD (left), a former Research Fellow, MGH-CEM, and now Senior Scientist at Rubius Therapeutics in Boston; and Shannon Tessier, PhD (right), Investigator at MGH-CEM, co-authored a study to develop a whole blood stabilization method that preserves sample integrity for up to 72 hours, making it possible to transport blood specimens further distances to central clinical laboratories for processing. (Photo copyrights: LinkedIn.)
Prior to microfluidic processing of their test samples, researchers applied a brief calcium chelation treatment. The result was efficient sorting of rare CTCs from blood drawn up to 72 hours prior, while keeping RNA intact and retaining cell viability.
“The critical achievement here,” says Tessier, “Is that the isolated tumor cells contain high-quality RNA that is suitable for demanding molecular assays, such as single-cell qPCR, droplet digital PCR, and RNA sequencing.”
Their testing involved 10 patients with metastatic prostate cancer. Sample integrity was verified by comparing CTC analysis results between fresh samples and preserved samples from the same patients using MGH-CEM’s own microfluidic CTC-iChip device.
Results showed a 92% agreement across 12 cancer-specific gene transcripts. For AR-V7, their preservation method achieved 100% agreement. “This is very exciting for clinicians,” declared David Miyamoto, MD, PhD, of Massachusetts General Hospital Cancer Center in the press release. “AR-V7 mRNA can only be detected using CTCs and not with circulating tumor DNA or other cell-free assays.”
Methodology Concerns and Future Confirmations
“Moving forward, an extremely exciting area in precision oncology is the establishment of patient-specific CTC cultures and xenograft models for drug susceptibility,” the study authors noted. “The lack of robust methods to preserve viable CTCs is a major roadblock towards this Holy Grail in liquid biopsy. In our preliminary experiments, we found that spiked tumor cells in blood remain highly viable (>80%) after 72 hours of hypothermic preservation.”
Despite this, they also acknowledge limitations on their current findings. The first is the need for larger-scale validation, as their testing involved a 10-patient sample group.
Second, they note that further studies will be needed to “more completely characterize whole-transcriptome alterations as a result of preservation, and to what extent they can be stabilized through other means, such as further cooling (e.g., non-freezing sub-zero temperatures) or metabolic depression.”
Researchers also note that their approach has multiple advantages for regulatory approval and further testing—GPIIb/IIIa inhibitors are both low-cost and already approved for clinical use, implementation requires no modification of existing isolation assays, and cold chain protocols are already in place allowing for easy adaptation to fit the needs of pathology groups, medical laboratories, and other diagnostics providers handling samples.
While still in its early stages, the methods introduced by the researchers at MGH-CEM show potential to allow both the facilities collecting samples and the clinical laboratories processing them greater flexibility and increased accuracy, as high-sensitivity assays and diagnostics continue to power the push toward personalized medicine and expand laboratory menus across the industry.
Research goal was to isolate circulating tumor cells in venipuncture samples with improved purity compared to standard spiral chips
Many research teams are pursuing the goal of creating assays that detect circulating tumor cells (CTCs) that would allow earlier and more accurate diagnosis of cancer. Now comes news of a unique technology developed at the University of Michigan (U-M) Ann Arbor that showed promised in an early study.
The method of using CTCs to diagnose cancer in patients, while further analyzing specific characteristics of a given cancer case, shows promise as an innovative tool for clinical laboratories and oncologists. However, current approaches face challenges when it comes to proving accuracy and establishing thresholds that might indicate the need for further action.
Researchers at U-M believe they may have solved that problem. They created “Labyrinth,” a “label-free microfluidic device” that condenses 637mm of channels—including 11 loops and 56 corners—onto a 500μm-wide chip that uses inertia and Dean flow to separate white blood cells and CTCs from venipuncture samples at rates as high as 2.5ml per minute. These results improve upon the traditional spiral chip design.
Publishing their findings in Cell Systems, first author of the study Eric Lin, PhD, noted, “With the recent advances in tools for genomic characterization, it is more compelling than ever to look at the tumor heterogeneity to understand tumor progression and resistance to therapies. The Labyrinth device enabled high yields of CTCs without the bias induced by antibody-based selection, allowing the identification of true biological tumor heterogeneity.”
The graphic above, taken from the University of Michigan study, demonstrates the “High-throughput and label-free Labyrinth device that enables single CTC isolation and gene expression characterization.” According to the researchers, “Labyrinth offers a cell-surface marker-independent single-cell isolation platform to study heterogeneous CTC subpopulations.” The U-M study shows promise in creating tools for oncologist and clinical laboratory cancer treatment. (Image copyright: University of Michigan/Cell Systems.)
Challenges in the Isolation of CTCs
The Labyrinth chip is not the first device to assist in isolating CTCs. The U-M study notes that while immune-affinity capture is a validated approach to prognosis, therapeutic monitoring and molecular diagnostics, it does not work with all cancer cases. The researchers also note the method creates challenges in single-cell analysis later.
Existing label-free methods of isolation, such as deterministic lateral displacement, microfluidic flow fractionation, and acoustic-based separation, avoid these concerns but face issues of their own. The researchers noted, “Issues encountered with these approaches include pore clogging, high-pressure drop, pre-fixation to prevent CTC loss, low throughput, and excessive non-specific cell retention.”
The researchers further clarified that a major factor separating the Labyrinth chip from other methods is the ability to identify CTC subpopulations without the need for manual selection based on positive or negative protein expression. Thus, improving the ability to conduct further single-cell analysis from the results. Testing of the Labyrinth chip involved a variety of cancer cell lines, including:
· Human breast (MCF-7);
· Pancreatic (PANC-1);
· Prostate (PC-3); and,
· Lung (H1650).
And while standard spiral chips are already a common method for conducting size-based sorting, the purity of results is less than ideal with thousands of other cells remaining in the sample.
The researchers reported that the Labyrinth chip recovered 91.5% (plus or minus 0.9%) of cancer cells and removed 91.4% (plus or minus 3.3%) of white blood cells in a spiked buffer test.
“Bigger cells, like most cancer cells, focus pretty fast due to the curvature. But the smaller the cell is, the longer it takes to get focused,” Sunitha Nagrath, PhD, Associate Professor of Chemical Engineering and a lead developer of the Labyrinth chip, stated in a U-M news release. “The corners produce a mixing action that makes the smaller white blood cells come close to the equilibrium position much faster.”
Labyrinth also supports a series configuration of multiple chips. While testing two chips in series, researchers noted “a two-log improvement in tumor cell enrichment over the single Labyrinth.” They claim this is a higher purity than other label-free methods they studied, while adding only five minutes to processing times.
Sunitha Nagrath, PhD (above), is an Associate Professor of Chemical Engineering at the University of Michigan, and one of the lead developers of the Labyrinth chip. “You cannot put a box around these cells,” she noted in the U-M news release. “The markers for them are so complex, there is no one marker we could target for all these stages.” (Photo copyright: University of Michigan.)
Current Testing Using the Labyrinth Chip
The chip is already in use in a clinical trial for an aggressive form of breast cancer by Max Wicha, MD, Madeline and Sidney Forbes Professor of Oncology, Founding Director Emeritus, University of Michigan Comprehensive Cancer Center, and co-author of the Cell Systems study, who lead the study along with Nagrath.
The trial involves the attempted activation of adult system cells by blocking the signaling molecule interleukin-6. Wicha suspects the molecule enables cancer stem cells as well. “We think that this may be a way to monitor patients in clinical trials,” he said in the U-M news release. “Rather than just counting the cells, by capturing them, we can perform molecular analysis [to] know what we can target with treatments.”
The news release further highlights how this chip is specifically suited to such a task. As cancer stem cells transition from stem-like cells to more ordinary cell types, their gene expression shifts as well. This creates an issue when using conventional cell targeting. Nagrath notes this concern, stating, “The markers for [cancer stem cells] are so complex, there is no one marker we could target for all these stages.”
The Labyrinth chip shows potential for overcoming one of the biggest hurdles to leveraging CTCs to diagnose cancers and develop personalized therapies. Currently, the chip can output to Fluidigm, DEPArray by Silicon Biosystems, and RainDance Technologies’ RainDrop Digital PCR System.
The U-M researchers hope that future research will yield additional applications and compatible systems to further improve the ability for medical laboratories to use CTCs in the early detection and monitoring of cancer cases.
Of the five trends described in a report published by Kalorama, only two made the list for both years: Consolidation within the IVD industry and growth in molecular point of care
What a difference one year can make in the most significant trends influencing the in vitro diagnostics (IVD) industry, which also influences clinical laboratories, the largest customers of IVD manufacturers. These insights come from comparing the top five IVD trends for 2016 as identified by Kalorama Information from its top five IVD trends that it says dominated during 2015.
Kalorama is a division of MarketResearch.com, a company that publishes market research in the life sciences. In a report titled, “Five IVD Market Trends to Watch for in 2016,” it published its picks for the top five trends in IVD testing for 2016. The five most prominent trends recognized by the healthcare research marketer are as follows: (more…)
