Though they are a mystery, once solved, Obelisks could lead to new biomarkers for clinical laboratory testing
Microbiologists and clinical laboratories know that human microbiota play many important roles in the body. Now, scientists from Stanford University have discovered an entirely new class of “viroid-like” lifeforms residing inside the human body. The researchers detected their presence in both the gut microbiome and saliva samples. Most interesting of all, the researchers are not sure what the lifeforms actually are.
The Stanford researchers, led by PhD student Ivan Zheludev, called the new discovery “Obelisks” due to their RNA structures, which are short and can fold into structures that resemble rods.
The scientists believe the Obelisks went undetected until now in the human microbiome due to their compact genetic elements, which are only around 1,000 characters or nucleotides in size. A typical human DNA structure consists of around three billion nucleotides.
In an article they published on the biology preprint server bioRxiv titled, “Viroid-like Colonists of Human Microbiomes,” the Stanford researchers wrote, “Here, we describe the ‘Obelisks,’ a previously unrecognized class of viroid-like elements that we first identified in human gut metatranscriptomic data. … Obelisks comprise a class of diverse RNAs that have colonized and gone unnoticed in human and global microbiomes.”
The researchers discovered that Obelisks “form their own distinct phylogenetic group with no detectable sequence or structural similarity to known biological agents.”
This is yet another example of how researchers are digging deeper into human biology and finding things never before identified or isolated.
“I am really impressed by the approach. The authors were really creative,” computational biologist Simon Roux, PhD (above) of the Department of Energy (DEO) Joint Genome Institute at Lawrence Berkeley National Laboratory told Science in response to the Stanford researcher’s published findings. “I think this [work] is one more clear indication that we are still exploring the frontiers of this viral universe. This is one of the most exciting parts of being in this field right now. We can see the picture of the long-term evolution of viruses on Earth start to slowly emerge.” How these findings might eventually spark new biomarkers for clinical laboratory testing remains to be seen. (Photo copyright: Berkeley Lab.)
Researchers Bewildered by Obelisks
In their study, “Zheludev and team searched 5.4 million datasets of published genetic sequences and identified almost 30,000 different Obelisks. They appeared in about 10% of the human microbiomes the team examined,” Science reported.
The Stanford researchers found that various types of Obelisks seem to inhabit different areas of the body. In one dataset, the Obelisks were found in half of the oral samples.
The function of Obelisks is unknown, but their discovery is bewildering experts.
Rod-like secondary structures encompassing the entire genome, and
Open reading frames coding for a novel protein superfamily, which the researchers dubbed “Oblins.”
At least half of the genetic material of the Obelisks was taken up by these Oblins. The researchers suspect those proteins may be involved in the replication process of the newly-discovered lifeforms.
The Oblins are also significantly larger than other genetic molecules that live inside cells and they do not have the genes to create protein shells that RNA viruses live within when they are outside of cells.
“Obelisks, therefore, need some kind of host. The researchers managed to identify one: A bacterium called Streptococcus sanguinis that lives mostly in dental plaque in our mouths. Exactly which other hosts obelisks inhabit is yet another mystery, as are what they do to their host and how they spread,” Vice reported.
“While we don’t know the ‘hosts’ of other Obelisks, it is reasonable to assume that at least a fraction may be present in bacteria,” the researchers noted in their bioRxiv paper.
Researchers are Stumped
The Stanford scientists were unable to identify any impact the Obelisks were having on their bacterial hosts—either negative or positive—or determine how they could spread between cells.
“These elements might not even be ‘viral’ in nature and might more closely resemble ‘RNA plasmids,’” they concluded in their paper.
The Stanford scientists are uncertain as to where or what the hosts of the Obelisks are, but they suspect that at least some of them are present in bacteria. However, Obelisks do not appear to be similar to any biological agents that could provide a link between genetic molecules and viruses.
And so, Obelisks are a true mystery—one the Stanford researchers may one day solve. If they do, new biomarkers for clinical laboratory testing may not be far behind.
Number of patients eligible for genome-driven oncology therapy is increasing, but the percentage who reportedly benefit from the therapy remains at less than 5%
Advances in precision medicine in oncology (precision oncology) are fueling the need for clinical laboratory companion diagnostic tests that help physicians choose the best treatment protocols. In fact, this is a fast-growing area of clinical diagnostics for the nation’s anatomic pathologists. However, some experts in the field of genome-based cancer treatments disagree over whether such treatments offer more hype than hope.
Prasad and his colleagues evaluated 31 US Food and Drug
Administration (FDA) approved drugs, which were “genome-targeted” or
“genome-informed” for 38 indications between 2006 and 2018. The researchers
sought to answer the question, “How many US patients with cancer are eligible
for and benefit annually from genome-targeted therapies approved by the US Food
and Drug Administration?”
They found that in 2018 only 8.33% of 609,640 patients with
metastatic cancer were eligible for genome-targeted therapy—though this was an
increase from 5.09% in 2006.
Even more telling from Prasad’s view, his research team concluded
that only 4.9% had benefited from such treatments. Prasad’s study found the
percentage of patients estimated to have benefited from genome-informed therapy
rose from 1.3% in 2006 to 6.62% in 2018.
“Although the number of patients eligible for genome-driven treatment has increased over time, these drugs have helped a minority of patients with advanced cancer,” the researchers concluded. “To accelerate progress in precision oncology, novel trial designs of genomic therapies should be developed, and broad portfolios of drug development, including immunotherapeutic and cytotoxic approaches, should be pursued.”
The graph above is based on data from a study published in Science titled, “Estimation of the Percentage of US Patients With Cancer Who Benefit from Genome-Driven Oncology,” co-authored by Vinay Prasad, MD, MPH, et al. (Image copyright: Science.)
A Value versus Volume Argument?
Hyman, who leads a team of oncologists that conduct dozens
of clinical trials and molecularly selected “basket studies” each year,
countered Prasad’s assertions by noting the increase in the number of patients
who qualify for precision oncology treatments.
As reported in Science, Hyman said during his AACR
presentation that Sloan Kettering matched 15% of the 25,000 patients’ tumors it
tested with FDA-approved drugs and 10% with drugs in clinical trials.
“I think this is certainly not hype,” he said during the
conference.
Hyman added that another 10% to 15% of patient tumors have a
DNA change that matches a potential drug tested in animals. He expects “basket”
trials to further increase the patient pool by identifying drugs that can work
for multiple tumor types.
The US National Institute of Health (NIH) describes “basket studies” as “a new sort of clinical studies to identify patients with the same kind of mutations and treat them with the same drug, irrespective of their specific cancer type. In basket studies, depending on the mutation types, patients are classified into ‘baskets.’ Targeted therapies that block that mutation are then identified and assigned to baskets where patients are treated accordingly.”
Are Expectations of Precision Medicine Exaggerated?
A profile in MIT Technology Review, titled, “The Skeptic: What Precision Medicine Revolution?,” describes Prasad’s reputation as a “professional scold” noting the 36-year-old professor’s “sharp critiques of contemporary biomedical research, including personalized medicine.” Nevertheless, Prasad is not alone in arguing that precision oncology’s promise is often exaggerated.
“Like most ‘moonshot’ medical research initiatives,
precision medicine is likely to fall short of expectations,” Joyner wrote.
“Medical problems and their underlying biology are not linear engineering
exercises and solving them is more than a matter of vision, money, and will.”
“Although some niche applications have been found for
precision medicine—and gene therapy is now becoming a reality for a few rare
diseases—the effects on public health are miniscule while the costs are astronomical,”
they wrote.
Hope for Precision Medicine Remains High
However, optimism over precision oncology among some industry leaders has not waned. Cindy Perettie, CEO of molecular information company Foundation Medicine of Cambridge, Mass., argues genome-directed treatments have reached an “inflection point.”
“Personalized cancer treatment is a possibility for more patients than ever thanks to the advent of targeted therapies,” she told Genetic Engineering and Biotechnology News. “With a growing number of new treatments—including two pan-tumor approvals—the need for broad molecular diagnostic tools to match patients with these therapies has never been greater. We continue to advance our understanding of cancer as a disease of the genome—one in which treatment decisions can be informed by insight into the genomic changes that contribute to each patient’s unique cancer.”
Prasad acknowledges genome-driven therapies are beneficial for some cancers. However, he told MIT Technology Review the data doesn’t support the “rhetoric that we’re reaching exponential growth, or that is taking off, or there’s an inflection point” signaling rapid new advancements.
“Right now, we are investing heavily in immunotherapy and heavily in genomic therapy, but in other categories of drugs, such as cytotoxic drugs, we have stopped investigating in them,” he told Medscape Medical News. “But it’s foolish to do this—we need to have the vision to look beyond the fads we live by in cancer medicine and do things in a broader way,” he added.
“So, I support broader funding because you have to sustain
efforts even when things are not in vogue if you want to make progress,” Prasad
concluded.
Is precision oncology a fad? Dark Daily has covered the advancements in precision medicine extensively over the past decade, and with the launch of our new Precision Medicine Institute website, we plan to continue reporting on further advancements in personalized medicine.
Time will tell if precision oncology can fulfill its
promise. If it does, anatomic pathologists will play an important role in
pinpointing patients most likely to benefit from genome-driven treatments.
One thing that the debate between proponents of precision
medicine in oncology and their critics makes clear is that more and better
clinical studies are needed to document the true effectiveness of target
therapies for oncology patients. Such evidence will only reinforce the
essential role that anatomic pathologists play in diagnosis, guiding
therapeutic decisions, and monitoring the progress of cancer patients.
Public health agencies and physicians would gain access to accurate, rapid dip-stick test that could give results similar to a pregnancy test
Tuberculosis is a major killer that ranks alongside HIV/AIDS as a leading cause of death worldwide. This deadly disease takes the lives of more than a million people each year. And, unfortunately, traditional medical laboratory testing using X-rays, blood/skin/sputum specimens, or the new molecular diagnostic systems can be time consuming and expensive.
Now, scientists at George Mason University (GMU) in Virginia have developed a urine test for tuberculosis (TB) that could lead to a dip-stick technology that would accurately and rapidly diagnose the deadly lung disease. Similar to a pregnancy test, if successfully developed for use in clinical settings, the dip-stick could not only enable public health agencies to test for TB more effectively, but also allow primary care physicians and other doctors to easily test their patients for TB at the point of care. However, it also could mean clinical laboratories might find their participation.
Nearly All TB Deaths Occur in Resource Strapped Areas
Such a breakthrough would certainly be a boon to public health and global healthcare, especially in resource strapped areas of the world. According to the World Health Organization (WHO), more than 95% of the 1.7 million TB deaths each year occur in low- and middle-income countries. This is one reason why an inexpensive and easy-to-use detection method for diagnosing the lung disease has long been sought. TB is curable, particularly if diagnosed early.
George Mason University scientists Alessandra Luchini, PhD (above left), and Lance Liotta, MD, PhD (above right), head an international team that has developed a nanotechnology that may lead to a simple dipstick urine test to detect tuberculosis. Such a test could greatly impact medical laboratories by reducing the need for traditional lab tests. (Photo copyrights: George Mason University.)
While past attempts at developing an accurate urine test for TB failed to reliably detect low concentrations of the sugar entity lipoarabinomannan (LAM) in HIV-negative, TB-infected patients, the GMU team developed a technology capable of doing so.
According to New Scientist, the GMU team’s test “uses tiny molecular cages embedded with a special dye that can catch and trap these sugar molecules. This makes the test capable of detecting the sugar at low concentrations, making the technique as much as 1,000 times more accurate [than] previous methods for detecting TB in urine.”
“We can measure now what could never be measured before,” Liotta noted in a news release.
World Health Organization Recommends Not Using Serodiagnostic Blood Tests
Common methods to detect TB currently include microscopy of sputum samples—a fast and accurate but expensive detection method (that also can diagnosis drug resistant disease)—or a skin test. A third test for TB, an Interferon-Gamma Release Assay, provides results in less than 24 hours but cannot distinguish between active and latent infection. In 2011, the WHO issued a Policy Recommendation urging countries to stop using serodiagnostic blood tests to diagnose TB, calling these tests unreliable and inaccurate. X-rays, meanwhile, detect only advanced lung damage.
In the GMU study, 48 Peruvian patients were chosen, all with active pulmonary TB, none of whom was infected with HIV or previously had received treatment for TB. According to the research, TB infections were detected with greater than 95% sensitivity, with TB-positive, HIV-negative patients having detectably higher concentrations of LAM in their urine compared to the controls. Patients who had more advanced disease also had elevated LAM concentrations. Eight of nine patients who were smear-negative and culture-positive for TB tested positive for urinary LAM.
“The technology can be configured in a variety of formats to detect a panel of previously undetectable very-low-abundance TB urinary analytes … This technology has broad implications for pulmonary TB screening, transmission control, and treatment management for HIV-negative patients,” the study’s authors told Science.
While The Scientist reports the GMU urine test gives results in about 12 hours, Luchini’s goal is for that timeframe to be dramatically shortened as the test is refined.
“We showed that our technology could be used to measure several different kinds of markers for TB in the urine and could be configured as a rapid test similar to a pregnancy test,” Luchini said in a GMU news release.
According to the university, GMU researchers will continue their work in Peru, where students will begin testing hundreds of patients as part of a research study. Grants from the National Institutes of Health and the Bill and Melinda Gates Foundation are funding their work. Luchini told New Scientist her goal is to make their TB urine test easier to use and to test it on thousands more people.
If successful, she predicts the test could be commercially available for physicians and clinical laboratories to use within three years. GMU’s biotechnology partner Ceres Nanosciences will be commercializing the technology, with the aim of making the test available worldwide, the university said in a statement.
Researchers believe they have begun to crack open a ‘black box’ involving the genomes and diseases of individual patients
Researchers in Switzerland are developing a new way to use mass spectrometry to explain why patients respond differently to specific therapies. The method potentially could become a useful tool for clinical laboratories that want to support the practice of precision medicine.
It is also one more example of how mass spectrometry is being used by researchers to develop new types of diagnostic assays that perform as well as traditional clinical laboratory testing methods, such as chemistry and immunoassay.
Thus, the latest research from the Swiss Federal Institute of Technology in Lausanne (EPFL) and ETH Zurich (ETHZ), will be of interest to pathology laboratory managers and medical laboratory scientists. It combines SWATH-MS (Sequential Window Acquisition of all Theoretical Mass Spectra) with genomics, transcriptomics, and other “omics,” to explain why patients respond differently to specific therapies, and to formulate a personalized strategy for individual treatment. (more…)
However, China has a shortage of well-trained pathologists, which is why some American lab organizations are establishing medical lab testing ventures in China
If experts are right, a company in China is poised to become the world’s largest at gene sequencing. In addition, the huge volume of genetic data it generates is expected to give this company the world’s largest database of genetic information.
Such developments could mean that, in just a few years, many pathologists and molecular Ph.D.s in the United States will be accessing this trove of genetic data as they conduct research to identify new biomarkers or work with clinical specimens.
The company at the center of all this attention is genome-sequencing giant BGI, located in Shenzhen, China. It owns 230 of the largest, high-throughput gene-sequencing machines and wants to become the world’s largest genome-mapping company. (more…)
