Tumour cells isolated from the blood of patients with triple negative breast cancer reveal similar cancer-driving mutations as those detected from standard biopsy, suggesting that circulating cells could one day replace tissue biopsies
The genetic fingerprint of a metastatic cancer is constantly changing, which means that the therapy that may have stopped a patient’s cancer growth today, won’t necessarily work tomorrow. Although doctors can continue to biopsy the cancer during the course of the treatment and send samples for genomic analysis, not all patients can receive repeat biopsies. Taking biopsies from metastatic cancer patients is an invasive procedure that it is frequently impossible due to the lack of accessible lesions.  Research suggest that tumour cells circulating in the blood of metastatic patients could give as accurate a genomic read-out as tumour biopsies.

“Counting the number of circulating tumour cells (CTCs) can tell us whether a patient’s cancer is aggressive, or whether it is stable and responding to therapy,” says the article’s first author Sandra V. Fernandez, Ph.D., assistant professor of Medical Oncology at Thomas Jefferson University. “Our work suggests that these cancer cells in the blood also accurately reflect the genetic status of the parent tumour or its metastases, potentially giving us a new and easy to source of genomic information to guide treatment.”

First discovered for their diagnostic potential in 2004, circulating tumour cells are beginning to be used in the clinic to help guide treatment decisions and track a patient’s progress as the cancer progresses. Although other studies have pooled the collected CTCs and compared their collective genetic signature to that of the primary tumour, this is the first study to look at the genomic signature of individual tumour cells in circulation. In order to isolate single tumour cells from the blood, the authors used a new technology, DEPArrayTM , in their laboratory.
The researchers compared tissue biopsies surgically removed from two patients with inflammatory breast cancer with circulating tumour cells (CTCs). Breast tissue samples from both patients showed a specific mutation in a region of a cancer-driving gene, p53. The authors studied this mutation in several CTCs isolated from both patients. They found that in several of the CTCs collected, the mutations matched with the tumour biopsy, however in one patient, some of circulating tumour cells had an additional mutation. “Since inflammatory breast cancer is a very rapidly changing disease, we think this additional mutation may have been acquired after the original surgical biopsy was taken,” said Dr. Fernandez. In the case where an additional p53 mutation was found, the blood to isolate CTCs were drawn one year later than the breast tissue biopsy was taken.
Although further work analyzing a greater number of genes and samples is needed, the work shows that CTCs offer the possibility of capturing the most current genomic information in an easy-to-obtain sample such as blood, thus helping guide treatment decisions. It also suggests that it may be necessary to test more than one cell for the most accurate reading, as the CTC population appears to be heterogenous. Thomas Jefferson University (TJU)

Tufts University School of Engineering researchers and collaborators from Texas A&M University have published the first research to use computational modelling to predict and identify the metabolic products of gastrointestinal (GI) tract microorganisms. Understanding these metabolic products, or metabolites, could influence how clinicians diagnose and treat GI diseases, as well as many other metabolic and neurological diseases increasingly associated with compromised GI function.

The human GI tract is colonized by billions of bacteria and other microorganisms, belonging to hundreds of species that are collectively termed ‘microbiota.’ Disruptions in the microbiota composition, and subsequently the metabolites derived from the microbiota, are increasingly correlated not only to GI diseases such as inflammatory bowel disease (IBD) and colitis, but also to insulin resistance and Type 2 diabetes.

‘There is increasing evidence that microbiota-derived metabolites play a significant role in modulating physiological functions of the gut,’ said Professor Kyongbum Lee, senior author on the paper and chair of the Department of Chemical and Biological Engineering in Tuft School of Engineering. ‘Emerging links between the GI tract microbiota and many other parts of the body, including the brain, suggest the tantalizing possibility to influence even cognition and behaviour through relatively benign interventions involving diets or probiotics.’

However, to date, only a handful of metabolites principally produced by microbiota—rather than the host organism itself—have been identified. Identifying microbiota-derived metabolites and understanding their effects on specific host functions could open up new avenues of basic and clinical research to develop safe, targeted therapies involving molecules that, by definition, constitute the natural chemical makeup of the host.

‘Current methods of identifying and quantifying these metabolites are unable to distinguish whether the metabolites are produced by the host or the microbiota,’ said Lee.

The newly reported approach models the microbiome as a single, complex network of reactions. By using computational algorithms for network analysis, virtual pathways can be constructed to determine possible metabolic products. Then, these products can be parsed into host-derived or microbiota-derived metabolites.

The research team focused on aromatic amino acids (AAAs) because their metabolites are involved in many of the more than 2,400 distinct reactions expressed in the microbiota as a whole.

‘In addition, we studied AAA-derived metabolites because AAAs can give rise to a variety of bioactive chemicals, such as salicylic acid, an anti-inflammatory compound, and serotonin, which is a neurotransmitter, obviously important in proper brain function,’ said Lee.

Work previously published in the Proceedings of the National Academy of Sciences from Lee’s collaborator Arul Jayaraman, professor in the Artie McFerrin Department of Chemical Engineering at Texas A&M University who holds a master’s from Tufts School of Engineering, had already demonstrated that indole, a bacterial metabolite derived from the aromatic amino acid tryptophan, caused an anti-inflammatory response in the gut and increased resistance to pathogen colonization that could lead to infection

The algorithmic model in the research published today predicted 49 different metabolites would appear as exclusive to the microbiota. In vivo tests on mice then confirmed the presence of more than half of the predicted metabolites, including two novel metabolites, which play a role in the pathways that regulate microbiota metabolism as well as host immune function.

Next steps for the team include identifying microbiota metabolites whose levels are either significantly elevated or depleted during diseases such as IBD or cancer, to find disease-specific markers and explore possible roles for these metabolites in disease progression.

‘Ultimately, the goal is to apply our models to arrive at a mechanistic understanding of the roles microbiota products may play in human physiology, and in turn, diagnose and treat disease,’ said Lee. ‘I think the potential for impact is immense.’ Tufts University

Following recent warnings by leading medical experts that early detection of liver disease by GPs in the UK is “virtually non-existent,” Professor W M C Rosenberg, FRCP, Peter Scheuer Chair of Liver Diseases, University College London and Peter Harrison, Managing Director UK at Siemens Healthcare have responded with commentary on how more needs to be done to ensure patients have access to newly available diagnostic treatment as early in the care pathway as possible, before the damage is irreversible.
Peter Harrison, Managing Director UK at Siemens Healthcare commented: “Early detection is key to the prevention and treatment of liver disease, yet a common misconception is that these tests are out of reach or too harmful for the patient to consider.”
“The reality is there are a number of easily-accessible non-invasive tests and extensive work has already gone into the development of both blood tests and non-invasive imaging techniques such as MRI and ultrasound elastography,” continues Peter Harrison. “New, simple tests such as Enhanced Liver Fibrosis (ELF) require only a small blood sample, and can indicate whether a patient suffers from slight, moderate or serious liver disease within the hour. With a range of effective solutions available, more needs to be done to ensure patients have access to diagnostic treatment as early in the care pathway as possible, before the damage is irreversible.”
Professor W M C Rosenberg, FRCP, Peter Scheuer Chair of Liver Diseases, University College London explained, “Once a diagnosis of liver disease has been made, clinicians need to determine the extent of the liver damage. The test we have traditionally had at our hands has been liver biopsy. This has been the only established reference test to quantify liver fibrosis, but it is an uncomfortable, daunting experience for the patient and an expensive process for the healthcare system.”
“The discovery of the ELF markers represents a significant advance in the diagnosis of patients with liver disease, with the potential to save tens of thousands of lives if adopted across England. The simple blood test gives us the ability to identify and quantify diagnosis from an early stage and is much more patient-friendly than existing methods. The test is being evaluated by certain CCGs but a real lack of awareness within the market means the test is not yet widely used. I believe clinicians must not only prepare for wider use of the test, but proactively find out where it sits locally and educate colleagues on the benefits.”

www.siemens.co.uk/healthcare

Ways to simplify treatments for tuberculosis (TB) to reduce drug resistance and make it easier for patients to complete their course of treatment have been trialled by two international groups involving UCL scientists.

The results from both trials found that novel drug combinations including the antibiotic moxifloxacin in TB treatment plans can approximately halve the number of pills that patients need to take but cannot shorten treatment time.

Most TB cases are curable after a six-month treatment regimen, providing patients stick to the treatment plan. Problems can arise if patients do not take their medication regularly, as the disease can recur or develop drug resistance.

Standard treatment plans require patients to take a cocktail of drugs every day for six months, which can be challenging and burdensome for patients to keep up with. The researchers found that with a new drug combination including moxifloxacin, taking daily medication for the first two months and then weekly high-dose medication for the last four months was equally effective at curing TB.

These results were from the RIFAQUIN phase III trial of 827 new cases of tuberculosis, led by researchers at UCL and St George’s, University of London, working with colleagues in Botswana, South Africa, Zambia and Zimbabwe. The trial found that drug combinations with moxifloxacin could help to reduce the number of pills needed but treatment could not be effectively shortened to four months.

The REMoxTB trial, a phase III trial of 1,931 patients at 50 sites in nine countries, also found that treatments could not be shortened from six to four months by using novel combinations including moxifloxacin.

Both trials involved researchers from the UCL Centre for Clinical Microbiology and Medical Research Council Clinical Trials Unit (MRC CTU) at UCL.

Professor Andrew Nunn, Scientific Programme Leader at the Medical Research Council Clinical Trials Unit, said: “New treatment strategies are urgently needed to battle the growing problem of drug resistance in TB. Resistant strains can develop when patients stop taking medication or take their treatment erratically because they start to feel better, allowing resistant TB bacteria to multiply. For example, an increasing number of TB strains are now resistant to the drug isoniazid, which has been a mainstay of treatment for over half a century. Strategies that make it easier for patients to complete treatments, such as the weekly treatments in RIFAQUIN, will help us to not only fight resistance but also to improve the quality of patients’ lives.” University College London

A class of drug for treating arthritis – all but shelved over fears about side effects – may be given a new lease of life following new research.

The new study, led by Imperial College London, sheds new light on the 10-year-old question of how COX-2 inhibitors – a type of non-steroidal anti-inflammatory drug (NSAID) – can increase the risk of heart attack in some people, and suggests a possible way to identify which patients should avoid using it.

NSAIDs – which include very familiar drugs such as ibuprofen, diclofenac and aspirin – are widely-used treatments for debilitating inflammatory conditions such as arthritis as well as being used for general pain relief worldwide. NSAIDs are also being investigated for their potential to prevent cancer. COX-2 inhibitors, which include Vioxx and Celebrex, were developed in the 1990s to avoid the risk of stomach ulcers caused by some NSAIDs, but after they were linked to an increased risk of heart attacks, they rapidly fell out of favour and some brands, including Vioxx, were withdrawn.

The new study, in mice and human volunteers, was led by Professor Jane Mitchell and Dr James Leiper. Professor Mitchell, from the National Heart and Lung Institute at Imperial, said: “Although the majority of arthritis sufferers could safely use COX-2 inhibitors, the fear of heart attacks has left some patients confused and worried about their medication and GPs nervous about prescribing them. This problem is made worse because we now know that most NSAIDs, not just COX-2 selective drugs, carry a similar risk of heart attacks in some patients.

“If we could identify which people have an increased risk, these patients could be offered more appropriate treatments – and we can start to look at ways of reducing or averting the risk entirely.”

NSAIDs work by preventing the production of prostaglandins – the chemical messengers in tissues and joints that trigger pain and inflammation. Prostaglandins are produced by two different enzymes, known as COX-1 and COX-2, which are found at sites of inflammation as well as in other sites around the body.

The study, funded by the Wellcome Trust, the British Heart Foundation and the Medical Research Council (MRC), looked at where and how removing COX-2 caused changes in gene activity in mice. They found that knocking out COX-2 caused changes in three genes in the kidney which predicted a rise in levels of a molecule linked to cardiovascular disease, called ADMA. In subsequent tests, the researchers found that taking NSAIDs led to a rise in ADMA levels in mice and in 16 human volunteers.

Dr James Leiper, from the MRC Clinical Sciences Centre at Imperial, said: ‘‘ADMA is an independent risk factor for cardiovascular disease. In people increases of ADMA similar to those we found are linked with significant increases in cardiovascular disease and death. Our discovery that COX-2 inhibitors raise ADMA levels provides a plausible mechanism for the increased cardiovascular risk associated with these drugs and provides insights into how this risk might be mitigated’

Professor Mitchell thinks that higher ADMA levels might work as an indicator of which patients are at greater risk of a heart attack.

“If we are right,” said Professor Mitchell, “ADMA could be used as a biomarker in a simple blood test to identify who may be at risk, and regular screening would allow GPs to monitor patients’ ADMA levels to ensure these remain within safe limits whilst taking the drug.”  The team are planning a clinical trial to test their idea. Imperial College London