Cellular healthcare is an approach that goes beyond clinical laboratory testing to identify the location of specific cancer cells and aid in treatment decisions
Advances in synthetic biology and genetic engineering are leading to development of bacterial biosensors that could eventually aid pathologists and clinical laboratories in diagnosis of many types of cancers.
One recent example comes from researchers at the University of California San Diego (UCSD) who worked with colleagues in Australia to engineer bacteria that work as “capture agents” and bind to tumorous material.
The KRAS gene is associated with colorectal cancer. The researchers named their development the Cellular Assay for Targeted CRISPR-discriminated Horizontal gene transfer (CATCH).
CATCH successfully detected cancer in the colons of mice. The researchers believe it could be used to diagnose cancers, as well as infections and other diseases, in humans as well, according to a UCSD news release.
“If bacteria can take up DNA, and cancer is defined genetically by a change in its DNA, then, theoretically, bacteria could be engineered to detect cancer,” gastroenterologist Daniel Worthley, PhD, a cancer researcher at Colonoscopy Clinic in Brisbane, Australia, told MedicalResearch.com. This research could eventually provide clinical laboratories and anatomic pathologists with new tools to use in diagnosing certain types of cancer. (Photo copyright: Colonoscopy Clinic.)
Tapping Bacteria’s Natural Competence
In their Science paper, the researchers acknowledged other synthetic biology achievements in cellular biosensors aimed at human disease. But they noted that more can be done by leveraging the “natural competence” skill of bacteria.
“Biosensors have not yet been engineered to detect specific extracellular DNA sequences and mutations. Here, we engineered naturally competent Acinetobacter baylyi (A. baylyi) to detect donor DNA from the genomes of colorectal cancer cells, organoids, and tumors,” they wrote.
“Many bacteria can take up DNA from their environment, a skill known as natural competence,” said Rob Cooper, PhD, co-first author of the study and a scientist at US San Diego’s Synthetic Biology Institute, in the news release. A. baylyi is a type of bacteria renowned for success in doing just that, the NCI article pointed out.
This enabled them to explore “free-floating DNA sequences on a genomic level.”
Those sequences were compared to “known cancer DNA sequences.”
A. baylyi (genetically modified) was tested on its ability to detect “mutated and healthy KRAS DNA.”
Only bacteria that had “taken up mutated copies of KRAS … would survive treatment with a specific drug.”
“It was incredible when I saw the bacteria that had taken up the tumor DNA under the microscope. The mice with tumors grew green bacterial colonies that had acquired the ability to be grown on antibiotic plates,” said Josephine Wright, PhD, Senior Research Fellow, Gut Cancer Group, South Australian Health and Medical Research Institute (SAHMRI), in the news release.
Detecting DNA from Cancer Cells In Vitro and in Mice
Findings in vitro and in mice include the following:
The engineered bacteria enabled detection of DNA with KRAS G12D from colorectal cancer cells made in the lab, NCI reported.
When mice were injected with colorectal cancer cells, the researchers’ technology found tumor DNA, Engadget reported.
The study adds to existing knowledge of horizontal gene transfer from bacteria to bacteria, according to UCSD.
“We observed horizontal gene transfer from the tumor to the sensor bacteria in our mouse model of colorectal cancer. This cellular assay for targeted, CRISPR-discriminated horizontal gene transfer (CATCH) enables the biodetection of specific cell-free DNA,” the authors wrote in Science.
“Colorectal cancer seemed a logical proof of concept as the colorectal lumen is full of microbes and, in the setting of cancer, full of tumor DNA,” gastroenterologist Daniel Worthley, PhD, a cancer researcher at Colonoscopy Clinic in Brisbane, Australia, told MedicalResearch.com.
Finding More Cancers and Treatment
More research is needed before CATCH is used in clinical settings. The scientists are reportedly planning on adapting CATCH to multiple bacteria that can locate other cancers and infections.
“The most exciting aspect of cellular healthcare … is not in the mere detection of disease. A laboratory can do that,” wrote Worthley in The Conversation. “But what a laboratory cannot do is pair the detection of disease (a diagnosis) with the cells actually responding to the disease [and] with appropriate treatment.
“This means biosensors can be programmed so that a disease signal—in this case, a specific sequence of cell-free DNA—could trigger a specific biological therapy, directly at the spot where the disease is detected in real time,” he added.
Clinical laboratory scientists, pathologists, and microbiologists may want to stay abreast of how the team adapts CATCH, and how bacterial biosensors in general continue to develop to aid diagnosis of diseases and improve ways to target treatment.
The 80 scientists and engineers that comprise the consortium believe synthetic biology can address key challenges in health and medicine, but technical hurdles remain
Synthetic biology now has a 20-year development roadmap. Many predict this fast-moving field of science will deliver valuable products that can be used in diagnostics—including clinical laboratory tests, therapeutics, and other healthcare products.
Eighty scientists from universities and companies around the world that comprise the Engineering Biology Research Consortium (EBRC) recently published the 20-year roadmap. They designed it to “provide researchers and other stakeholders (including government funders)” with what they hope will be “a go-to resource for engineering/synthetic biology research and related endeavors,” states the EBRC Roadmap website.
Medical laboratories and clinical pathologists may soon have new tools and therapies for targeting specific diseases. The EBRC defines synthetic biology as “the design and construction of new biological entities such as enzymes, genetic circuits, and cells or the redesign of existing biological systems. Synthetic biology builds on the advances in molecular, cell, and systems biology and seeks to transform biology in the same way that synthesis transformed chemistry and integrated circuit design transformed computing.”
Synthetic biology is an expanding field and there are predictions that it may produce research findings that can be adapted for use in clinical pathology diagnostics and treatment for chronic diseases, such as cancer.
Another goal of the roadmap is to encourage federal
government funding for synthetic biology.
“The question for government is: If all of these avenues are now open for biotechnology development, how does the US stay ahead in those developments as a country?” said Douglas Friedman, EBRC’s Executive Director, in a news release. “This field has the ability to be truly impactful for society and we need to identify engineering biology as a national priority, organize around that national priority, and take action based on it.”
Designing or Redesigning Life Forms for Specific
Applications
Synthetic biology is an interdisciplinary field that combines
elements of engineering, biology, chemistry, and computer science. It enables
the design and construction of new life forms—or redesign of existing ones—for
a multitude of applications in medicine and other fields.
Another recent example comes from the Wyss Institute at Harvard. Scientist there developed a direct-to-consumer molecular diagnostics platform called INSPECTR that, they say, uses programmable synthetic biosensors to detect infectious pathogens or host cells.
The Wyss Institute says on its website that the platform can
be packaged as a low-cost, direct-to-consumer test similar to a home pregnancy
test. “This novel approach combines the specificity, rapid development, and
broad applicability of a molecular diagnostic with the low-cost, stability, and
direct-to-consumer applicability of lateral flow immunoassays.”
In March, Harvard announced that it had licensed the technology to Sherlock Biosciences.
Howard Salis, PhD (above), Associate Professor of biological engineering and chemical engineering at Pennsylvania State University (Penn State), co-chaired the EBRC Roadmapping Working Group that produced the roadmap. In a Penn State news story, Salis explained synthetic biology’s potential. “There are both traditional and startup companies leveraging synthetic biology technologies to develop novel biotech products,” he said. “Organisms that produce biorenewable materials; diagnostics to detect the Zika virus, Ebola and tuberculosis; and soil bacteria that fix nitrogen into ammonia for improved plant growth.” (Photo copyright: Twitter.)
Fundamental Challenges with Synthetic Biology
The proponents of synthetic biology hope to make it easier
to design and build these systems, in much the same way computer engineers
design integrated circuits and processors. The EBRC Roadmap may help scientist
worldwide achieve this goal.
However, in “What is Synthetic/Engineering Biology?” the EBRC also identifies the fundamental challenges facing the field. Namely, the complexity and unpredictability inherent in biology, and a limited understanding of how biological components interact.
The EBRC roadmap report, “Engineering Biology: A Research
Roadmap for the Next-Generation Bioeconomy,” covers five categories of applications:
Health and medicine are of primary interest to pathologists.
Synthetic Biology in Health and Medicine
The Health and Medicine section of the report identifies
four broad societal challenges that the EBRC believes can be addressed by
synthetic biology. For each, the report specifies engineering biology
objectives, including efforts to develop new diagnostic technologies. They
include:
Existing and emerging infectious diseases: Objectives include development of tools for treating infections, improving immunity, reducing dependence on antibiotics, and diagnosing antimicrobial-resistant infections. The authors also foresee tools for rapid characterization and response to “known and unknown pathogens in real time at population scales.”
Non-communicable diseases and disorders, including cancer, heart disease, and diabetes: Objectives include development of biosensors that will measure metabolites and other biomolecules in vivo. Also: tools for identifying patient-specific drugs; tools for delivering gene therapies; and genetic circuits that will foster tissue formation and repair.
Environmental health threats, such as toxins, pollution, and injury: Objectives include systems that will integrate wearable tech with living cells, improve interaction with prosthetics, prevent rejection of transplanted organs, and detect and repair of biochemical damage.
Healthcare access and personalized medicine: The authors believe that synthetic biology can enable personalized treatments and make new therapies more affordable.
Technical Themes
In addition to these applications, the report identifies
four “technical themes,” broad categories of technology that will spur the
advancement of synthetic biology:
Gene editing, synthesis, and assembly: This refers to tools for producing chromosomal DNA and engineering whole genomes.
Biomolecule, pathway, and circuit engineering: This “focuses on the importance, challenges, and goals of engineering individual biomolecules themselves to have expanded or new functions,” the roadmap states. This theme also covers efforts to combine biological components, both natural and non-natural, into larger, more-complex systems.
Host and consortia engineering: This “spans the development of cell-free systems, synthetic cells, single-cell organisms, multicellular tissues and whole organisms, and microbial consortia and biomes,” the roadmap states.
Data Integration, modeling, and automation: This refers to the ability to apply engineering principles of Design, Build, Test and Learn to synthetic biology.
The roadmap also describes the current state of each
technology and projects likely milestones at two, five, 10, and 20 years into
the future. The 2- and 5-year milestones are based on “current or recently
implemented funding programs, as well as existing infrastructure and facilities
resources,” the report says.
The longer-term milestones are more ambitious and may
require “significant technical advancements and/or increased funding and
resources and new and improved infrastructure.”
Synthetic biology is a significant technology that could
bring about major changes in clinical pathology diagnostics and treatments.
It’s well worth watching.
Understanding the unknown functions of these genes may lead to the creation of new diagnostic tests for clinical laboratories and anatomic pathology groups
Once again, J. Craig Venter, PhD, is charting new ground in gene sequencing and genomic science. This time his research team has built upon the first synthetic cell they created in 2010 to build a more sophisticated synthetic cell. Their findings from this work may give pathologists and medical laboratory scientists new tools to diagnose disease.
Recently the research team at the J. Craig Venter Institute (JCVI) and Synthetic Genomics, Inc. (SGI) published their latest findings. Among the things they learned is that science still does not understand the functions of about a third of the genes required for their synthetic cells to function. (more…)
