Technology allows retrievable information to be recorded directly into the genomes of living bacteria, but will this technology have value in clinical laboratory testing?
Researchers at Harvard Medical School have successfully used CRISPR technology to encode an image and a short film into the Deoxyribonucleic acid (DNA) of bacteria. Their goal is to develop a way to record and store retrievable information in the genomes of living bacteria. A story in the Harvard Gazette described the new technology as a sort of “biological hard drive.”
It remains to be seen how this technology might impact medical laboratories and pathology groups. Nevertheless, their accomplishment is another example of how CRISPR technology is leading to new insights and capabilities that will advance genetic medicine and genetic testing.
Recording Complex Biological Events in the Genomes of Bacteria
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) are DNA sequences containing short, repetitive base sequences found in the genomes of bacteria and other micro-organisms that can facilitate the modification of genes within organisms. The term CRISPR also can refer to the whole CRISPR-Cas9 system, which can be programmed to pinpoint certain areas of genetic code and to modify DNA at exact locations.
Led by George Church, PhD, faculty member and Professor of Genetics at Harvard Medical School, the team of researchers at the Wyss Institute for Biologically Inspired Engineering at Harvard University in Cambridge, Mass., constructed a molecular recorder based on CRISPR that enables cells to obtain DNA information and produce a memory in the genome of bacteria. With it, they inserted a GIF image and a five-frame movie into the bacteria’s DNA.
“As promising as this was, we did not know what would happen when we tried to track about 100 sequences at once, or if it would work at all,” noted Seth Shipman, PhD, Postdoctoral Fellow, and one of the authors of the study in the Harvard Gazette story. “This was critical since we are aiming to use this system to record complex biological events as our ultimate goal.”
Translating Digital Information into DNA Code
The team transferred an image of a human hand and five frames of a movie of a running horse onto nucleotides to imbed data into the genomes of bacteria. This produced a code relating to the pixels of each image. CRISPR was then used to insert genetic code into the DNA of Escherichia coli (E-coli) bacteria. The researchers discovered that CRISPR did have the ability to encode complex information into living cells.
“The information is not contained in a single cell, so each individual cell may only see certain bits or pieces of the movie. So, what we had to do was reconstruct the whole movie from the different pieces,” stated Shipman in a BBC News article. “Maybe a single cell saw a few pixels from frame one and a few pixels from frame four … so we had to look at the relation of all those pieces of information in the genomes of these living cells and say, ‘Can we reconstruct the entire movie over time?’”
The team used an image of a digitized human hand because it embodies the type of intricate data they wish to use in future experiments. A movie also was used because it has a timing component, which could prove to be beneficial in understanding how a cell and its environment may change over time. The researchers chose one of the first motion pictures ever recorded—moving images of a galloping horse by Eadweard Muybridge, a British photographer and inventor from the late 19th century.
“We designed strategies that essentially translate the digital information contained in each pixel of an image or frame, as well as the frame number, into a DNA code that, with additional sequences, is incorporated into spacers. Each frame thus becomes a collection of spacers,” Shipman explained in the Harvard Gazette story. “We then provided spacer collections for consecutive frames chronologically to a population of bacteria which, using Cas1/Cas2 activity, added them to the CRISPR arrays in their genomes. And after retrieving all arrays again from the bacterial population by DNA sequencing, we finally were able to reconstruct all frames of the galloping horse movie and the order they appeared in.”
In the video above, Wyss Institute and Harvard Medical School researchers George Church, PhD, and Seth Shipman, PhD, explain how they engineered a new CRISPR system-based technology that enables the chronological recording of digital information, like that representing still and moving images, in living bacteria. Click on the image above to view the video. It is still too early to determine how this technology may be useful to pathologists and clinical laboratory scientists. (Caption and video copyright: Wyss Institute at Harvard University.)
“In this study, we show that two proteins of the CRISPR system, Cas1 and Cas2, that we have engineered into a molecular recording tool, together with new understanding of the sequence requirements for optimal spacers, enables a significantly scaled-up potential for acquiring memories and depositing them in the genome as information that can be provided by researchers from the outside, or that, in the future, could be formed from the cells natural experiences,” stated Church in the Harvard Gazette story. “Harnessed further, this approach could present a way to cue different types of living cells in their natural tissue environments into recording the formative changes they are undergoing into a synthetically created memory hotspot in their genomes.”
Encoding Information into Cells for Clinical Laboratory Testing and Therapy
The team plans to focus on creating molecular recording devices for other cell types and on enhancing their current CRISPR recorder to memorize biological information.
“One day, we may be able to follow all the developmental decisions that a differentiating neuron is taking from an early stem cell to a highly-specialized type of cell in the brain, leading to a better understanding of how basic biological and developmental processes are choreographed,” stated Shipman in the Harvard Gazette story. Ultimately, the approach could lead to better methods for generating cells for regenerative therapy, disease modeling, drug testing, and clinical laboratory testing.
According to Shipman in the BBC News article, these cells could “encode information about what’s going on in the cell and what’s going on in the cell environment by writing that information into their own genome.”
This field of research is still new and its full potential is not yet understood. However, if this capability can be developed, there could be opportunities for pathologists and molecular chemists to develop methods for in vivo monitoring of a patient’s cell function. These methods could prove to be an unexpected new way for clinical laboratories to add value and become more engaged with the clinical care team.
SHERLOCK makes accurate, fast diagnoses for about 61-cents per test with no refrigeration needed; could give medical laboratories a new diagnostic tool
The tool is called SHERLOCK, which stands for (Specific High-sensitivity Enzymatic Reporter unLOCKing). And it is causing excitement in the scientific community for several reasons:
It can detect pathogens in extremely small amounts of genetic matter;
Tests can be performed using urine and/or saliva rather than blood;
The tests are extremely sensitive; and they
Cost far less than the diagnostic tests currently in use.
How SHERLOCK and CRISPR Differ and Why That’s Important
Scientists have long suspected that CRISPR could be used to detect viruses. However, far more attention has been given to the its genome editing capabilities. And, there are significant differences between how CRISPR and SHERLOCK work. According to the Science article, when CRISPR is used to edit genes, a small strip of RNA directs an enzyme capable of cutting DNA to a precise location within a genome. The enzyme that CRISPR uses is called Cas9 (CRISPR associated protein 9). It works like scissors, snipping the strand of DNA, so that it is either damaged or replaced by a healthy, new sequence.
SHERLOCK, however, uses a different enzyme—Cas13a (originally dubbed C2c2 by the researchers who discovered it). Cas13a goes to RNA, rather than DNA, and once it starts cutting, it doesn’t stop. It chops through any RNA it encounters. The researchers who developed SHERLOCK describe these cuts as “collateral cleavage.” According to an article published by STAT, “All that chopping generates a fluorescent signal that can be detected with a $200 device or, sometimes, with the naked eye.”
The screenshot above is from a video in which Feng Zhang, PhD (center), a Core Member of the Broad Institute at MIT and one of the lead researchers working on SHERLOCK, and his research team, explain the difference and value SHERLOCK will make in the detection of diseases like Zika. Click on the image above to watch the video. (Video copyright: Broad Institute/MIT.)
Early Stage Detection in Clinical Laboratories
A research paper published in Science states that SHERLOCK can provide “rapid DNA or RNA detection with attomolar sensitivity and single-base mismatch specificity.” Attomolar equates to about one part per quintillion—a billion-billion. According to the article on the topic also published in Science, “The detection sensitivity of the new CRISPR-Cas13a system for specific genetic material is one million times better than the most commonly used diagnostic technique.” Such sensitivity suggests that clinical laboratories could detect pathogens at earlier stages using SHERLOCK.
The Stat article notes that, along with sensitivity, SHERLOCK has specificity. It can detect a difference of a single nucleotide, such as the difference between the African and Asian strains of Zika (for example, the African strain has been shown to cause microcephaly, whereas the Asian strain does not). Thus, the combination of sensitivity and specificity could mean that SHERLOCK would be more accurate and faster than other diagnostic tests.
Clinicians in Remote Locations Could Diagnose and Treat Illness More Quickly
Perhaps one of the most important aspects of SHERLOCK is the portability and durability of the test. It can be performed on glass fiber paper and works even after the components have been freeze dried. “We showed that this system is very stable, so you can really put it on a piece of paper and it will survive. You don’t have to refrigerate it all the times,” stated Feng Zhang, PhD, in an interview with the Washington Post. Zhang is a Core Member of the Broad Institute at MIT and was one of the scientists who developed CRISPR.
The researchers note that SHERLOCK could cost as little as 61-cents per test to perform. For clinicians working in remote locations with little or no power, such a test could improve their ability to diagnose and treatment illness in the field and possibly save lives.
“If you had something that could be used as a screening test, very inexpensively and rapidly, that would be a huge advance, particularly if it could detect an array of agents,” stated William Schaffner, MD, Professor and Chair of the Department of Preventive Medicine at Vanderbilt University Medical Center, in the Post article. Schaffner describes the Broad Institute’s research as being “very, very provocative.”
The test could radically change the delivery of care in more modern settings, as well. “It looks like one significant step on the pathway [that] is the Holy Grail, which is developing point-of-care, or bedside detection, [that] doesn’t require expensive equipment or even reliable power,” noted Scott Weaver, PhD, in an article on Big Think. Weaver is a Professor and Director at the Institute for Human Infections and Immunity University of Texas Medical Branch in Galveston, Texas.
Just the Beginning
Anatomic pathologists and clinical laboratories will want to follow SHERLOCK’s development. It could be on the path to fundamentally transforming the way disease gets diagnosed in their laboratories and in the field.
According to the Post article, “The scientists have filed several US patent applications on SHERLOCK, including for uses in detecting viruses, bacteria, and cancer-causing mutations.” In addition to taking steps to secure patents on the technology, the researchers are exploring ways to commercialize their work, as well as discussing the possibility of launching a startup. However, before this technology can be used in medical laboratory testing, SHERLOCK will have to undergo the regulatory processes with various agencies, including applying for FDA approval.
U.S. Patent and Trademark Office will hold hearings to determine whether University of California Berkeley, or Broad Institute of Harvard and MIT, should receive patents for new genomic engineering technique
In the race to master gene-editing in ways that will advance genetic medicine and patient care, one of the hottest technologies is CRISPR, which stands for Clustered Regularly Interspaced Short Palindromic Repeats. But now a patent fight has the potential to complicate how pathologists and other scientists use this exciting technology.
This dispute over the CRISPR patent—a tool that has been hailed as one of the biggest biotech breakthroughs of the decade—will likely be settled in the coming months by the United States Patent and Trademark Office (USPTO).
The USPTO will be reviewing key patents awarded for what is called CRISPR/Cas9. The technology is already generating novel therapies for diseases, which should create new opportunities for pathologists and medical laboratories. (more…)
Most pathologists know that CRISPR can permanently repair DNA to eliminate diseases that plague families, but also could be used for less ethical purposes, say experts
Gene editing is a rapidly developing field that is expected to create new diagnostic needs that can be filled by pathologists and by new medical laboratory tests. However, experts in bio-ethics are voicing concerns that gene editing for clinical purposes is moving forward without proper consideration of important ethical issues and are calling for a moratorium on use of gene editing for clinical purposes.
What is speeding the development of gene editing is use of the tool known as CRISPR/Cas9. It is a gene-editing tool that makes it possible to genetically modify DNA for therapeutic purposes. It provides medical scientists the ability to repair damaged genes that cause or predispose individuals to disease. (more…)
If further research confirms these findings, clinical laboratory identification of cancer cells could lead to new treatments for certain childhood cancers
Can cancer cells be changed into normal healthy cells? According to molecular biologists at the Cold Spring Harbor Laboratory (CSHL) in Long Island the answer is, apparently, yes. At least for certain types of cancer. And clinical laboratories and anatomic pathologists may play a key role in identifying these specific cancer cells and then guiding physicians in selecting the most appropriate therapies.
The cancer cells in question are called rhabdomyosarcoma (RMS) and are “particularly aggressive,” according to ScienceAlert. Generally, and most sadly, the cancer primarily affects children below the age of 18. It begins in skeletal muscle, mutates throughout the body, and is often deadly.
“Treatment usually involves chemotherapy, surgery, and radiation procedures. Now, new research by scientists at Cold Spring Harbor Laboratory demonstrates differentiation therapy as a new treatment option for RMS,” Genetic Engineering and Biotechnology News (GEN) reported.
For those young cancer patients, this new research could become a lifesaving therapy as further studies validate the approach, which has been in development for six years.
“Every successful medicine has its origin story,” said Christopher Vakoc, MD, PhD (above), a molecular biologist at Cold Spring Harbor Laboratory, who led the team that develop the method for converting cancer cells into healthy cells. “And research like this is the soil from which new drugs are born.” As these findings are confirmed, it may be that clinical laboratories and anatomic pathologists will be needed to identify the specific cancer cells in patients once treatment is developed. (Photo copyright: Cold Spring Harbor Laboratory.)
Differentiation Therapy
According to an article in the Chinese Journal of Cancer on the National Library of Medicine website, “Differentiation therapy is based on the concept that a neoplasm is a differentiation disorder [aka, differentiation syndrome] or a dedifferentiation disease. In response to the induction of differentiation, tumor cells can revert to normal or nearly normal cells, thereby altering their malignant phenotype and ultimately alleviating the tumor burden or curing the malignant disease without damaging normal cells.”
Vakoc and his team first pursued differentiation therapy to treat Ewing sarcoma, a pediatric cancer that forms in soft tissues or in bone. In January 2023, GEN reported that the researchers had discovered that “Ewing sarcoma could potentially be stopped by developing a drug that blocks the protein known as ETV6.”
“This protein is present in all cells. But when you perturb the protein, most normal cells don’t care,” Vakoc told GEN. “The process by which the sarcoma forms turns this ETV6 molecule—this relatively innocuous, harmless protein that isn’t doing very much—into something that’s now controlling a life-death decision of the tumor cell.”
The researchers discovered that when ETV6 was blocked in lab-grown Ewing sarcoma cells, the cells became normal, healthy cells. “The sarcoma cell reverts back into being a normal cell again,” they told GEN. “The shape of the cell changes. The behavior of the cells changes. A lot of the cells will arrest their growth. It’s really an explosive effect.”
The scientists then turned their attention on Rhabdomyosarcoma to see if they could elicit a similar response.
“In this study, we developed a high-throughput genetic screening method to identify genes that cause rhabdomyosarcoma cells to differentiate into normal muscle. We used this platform to discover the protein NF-Y as an important molecule that contributes to rhabdomyosarcoma biology. CRISPR-based genetic targeting of NF-Y converts rhabdomyosarcoma cells into differentiated muscle, and we reveal the mechanism by which this occurs,” they wrote in PNAS.
“Scientists have successfully induced rhabdomyosarcoma cells to transform into normal, healthy muscle cells. It’s a breakthrough that could see the development of new therapies for the cruel disease, and it could lead to similar breakthroughs for other types of human cancers,” ScienceAlert reported.
“The cells literally turn into muscle,” Vakoc told ScienceAlert. “The tumor loses all cancer attributes. They’re switching from a cell that just wants to make more of itself to cells devoted to contraction. Because all its energy and resources are now devoted to contraction, it can’t go back to this multiplying state,” he added.
Promising New Therapies for Multiple Cancers in Children
Differentiation therapy as a treatment option gained popularity when “scientists noticed that leukemia cells are not fully mature, similar to undifferentiated stem cells that haven’t yet fully developed into a specific cell type. Differentiation therapy forces those cells to continue their development and differentiate into specific mature cell types,” ScienceAlert noted.
Vakoc and his team had previously “effectively reversed the mutation of the cancer cells that emerge in Ewing sarcoma.” It was those promising results from differentiation therapy that inspired the team to push further and attempt success with rhabdomyosarcoma.
Their results are “a key step in the development of differentiation therapy for rhabdomyosarcoma and could accelerate the timeline for which such treatments are expected,” ScienceAlert commented.
Developing New Therapies for Deadly Cancers
Vakoc and his team are considering differentiation therapy’s potential effectiveness for other types of cancer as well. They note that “their technique, now demonstrated on two different types of sarcoma, could be applicable to other sarcomas and cancer types since it gives scientists the tools needed to find how to cause cancer cells to differentiate,” ScienceAlert reported.
“Since many forms of human sarcoma exhibit a defect in cell differentiation, the methodology described here might have broad relevance for the investigation of these tumors,” the researchers wrote in PNAS.
Clinical laboratories and anatomic pathologist play a critical role in identifying many types of cancers. And though any treatment that comes from the Cold Spring Harbor Laboratory research is years away, it illustrates how new insights into the basic dynamics of cancer cells is helping researchers develop effective therapies for attacking those cancers.
