Tag Archives: cancer

Hit and run gene therapy?

The approach looks promising but there’s a still long way to go before this ‘simpler, gentler’ approach to gene therapy will make its way into any treatments. From an August 30, 2017 news item on Nanowerk,

A new biomedical tool using nanoparticles that deliver transient gene changes to targeted cells could make therapies for a variety of diseases — including cancer, diabetes and HIV — faster and cheaper to develop, and more customizable.

The tool, developed by researchers at Fred Hutchinson Cancer Research Center and tested in preclinical models, is described in a paper published August 30 [2017] in Nature Communications.

This animation demonstrates the approach,

Biodegradable nanoparticles (orange) carry short-lived gene therapy to specific cells (light teal). Animation by Kimberly Carney / Fred Hutch News Service

An August 30, 2017 Fred Hutchinson Cancer Research Center (Fred Hutch) news release (from news release received via email; also on EurekAlert) by Sabrina Richards, which originated the news item, elucidates further (Note: Some links and notes have been removed),

“Our goal is to streamline the manufacture of cell-based therapies,” said lead author DR. MATTHIAS STEPHAN [6], a faculty member in the Fred Hutch Clinical Research Division and an expert in developing biomaterials. “In this study, we created a product where you just add it to cultured cells and that’s it — no additional manufacturing steps.”

Stephan and his colleagues developed a nanoparticle delivery system to extend the therapeutic potential of messenger RNA, which delivers molecular instructions from DNA to cells in the body, directing them to make proteins to prevent or fight disease.

The researchers’ approach was designed to zero in on specific cell types — T cells of the immune system and blood stem cells — and deliver mRNA directly to the cells, triggering short-term gene expression. It’s called “hit-and-run” genetic programming because the transient effect of mRNA does not change the DNA, but it is enough to make a permanent impact on the cells’ therapeutic potential.

Stephan and colleagues used three examples in the Nature Communications paper to demonstrate their technology:

* Nanoparticles carried a gene-editing tool to T cells of the immune system that snipped out their natural T-cell receptors, and then was paired with genes encoding a “chimeric antigen receptor” or CAR, a synthetic molecule designed to attack cancer.
* Targeted to blood stem cells, nanoparticles were equipped with mRNA that enabled the stem cells to multiply and replace blood cancer cells with healthy cells when used in bone marrow transplants.
* Nanoparticles targeted to CAR-T cells and containing foxo1 mRNA, which signals the anti-cancer T cells to develop into a type of “memory” cell that is more aggressive and destroys tumor cells more effectively and maintains anti-tumor activity longer.

Other attempts to engineer mRNA into disease-fighting cells have been tricky. The large messenger molecule degrades quickly before it can have an effect, and the body’s immune system recognizes it as foreign — not coming from DNA in the nucleus of the cell — and destroys it.

Stephan and his Fred Hutch collaborators devised a workaround to those hurdles.

“We developed a nanocarrier that binds and condenses synthetic mRNA and protects it from degradation,” Stephan said. The researchers surrounded the nanoparticle with a negatively charged envelope with a targeting ligand attached to the surface so that the particle selectively homes in and binds to a particular cell type.

The cells swallow up the tiny carrier, which can be loaded with different types of manmade mRNA. “If you know from the scientific literature that a signaling pathway works in synergy, you could co-deliver mRNA in a single nanoparticle,” Stephan said. “Every cell that takes up the nanoparticle can express both.”

The approach involves mixing the freeze-dried nanoparticles with water and a sample of cells. Within four hours, cells start showing signs that the editing has taken effect. Boosters can be given if needed. Made from a dissolving biomaterial, the nanoparticles are removed from the body like other cell waste.

“Just add water to our freeze-dried product,” Stephan said. Since it’s built on existing technologies and doesn’t require knowledge of nanotechnology, he intends for it to be an off-the-shelf way for cell-therapy engineers to develop new approaches to treating a variety of diseases.

The approach could replace labor-intensive electroporation, a multistep cell-manufacturing technique that requires specialized equipment and clean rooms. All the handling ends up destroying many of the cells, which limits the amount that can be used in treatments for patients.

Gentler to cells, the nanoparticle system developed by the Fred Hutch team showed that up to 60 times more cells survive the process compared with electroporation. This is a critical feature for ensuring enough cells are viable when transferred to patients.

“You can imagine taking the nanoparticles, injecting them into a patient and then you don’t have to culture cells at all anymore,” he said.

Stephan has tested the technology is cultured cells in the lab, and it’s not yet available as a treatment. Stephan is looking for commercial partners to move the technology toward additional applications and into clinical trials where it could be developed into a therapy.

Here’s a link to and a citation for the paper,

Hit-and-run programming of therapeutic cytoreagents using mRNA nanocarriers by H. F. Moffett, M. E. Coon, S. Radtke, S. B. Stephan, L. McKnight, A. Lambert, B. L. Stoddard, H. P. Kiem, & M. T. Stephan. Nature Communications 8, Article number: 389 (2017) doi:10.1038/s41467-017-00505-8 Published online: 30 August 2017

This paper is open access.

Training drugs

This summarizes some of what’s happening in nanomedicine and provides a plug (boost) for the  University of Cambridge’s nanotechnology programmes (from a June 26, 2017 news item on Nanowerk),

Nanotechnology is creating new opportunities for fighting disease – from delivering drugs in smart packaging to nanobots powered by the world’s tiniest engines.

Chemotherapy benefits a great many patients but the side effects can be brutal.
When a patient is injected with an anti-cancer drug, the idea is that the molecules will seek out and destroy rogue tumour cells. However, relatively large amounts need to be administered to reach the target in high enough concentrations to be effective. As a result of this high drug concentration, healthy cells may be killed as well as cancer cells, leaving many patients weak, nauseated and vulnerable to infection.

One way that researchers are attempting to improve the safety and efficacy of drugs is to use a relatively new area of research known as nanothrapeutics to target drug delivery just to the cells that need it.

Professor Sir Mark Welland is Head of the Electrical Engineering Division at Cambridge. In recent years, his research has focused on nanotherapeutics, working in collaboration with clinicians and industry to develop better, safer drugs. He and his colleagues don’t design new drugs; instead, they design and build smart packaging for existing drugs.

The University of Cambridge has produced a video interview (referencing a 1966 movie ‘Fantastic Voyage‘ in its title)  with Sir Mark Welland,

A June 23, 2017 University of Cambridge press release, which originated the news item, delves further into the topic of nanotherapeutics (nanomedicine) and nanomachines,

Nanotherapeutics come in many different configurations, but the easiest way to think about them is as small, benign particles filled with a drug. They can be injected in the same way as a normal drug, and are carried through the bloodstream to the target organ, tissue or cell. At this point, a change in the local environment, such as pH, or the use of light or ultrasound, causes the nanoparticles to release their cargo.

Nano-sized tools are increasingly being looked at for diagnosis, drug delivery and therapy. “There are a huge number of possibilities right now, and probably more to come, which is why there’s been so much interest,” says Welland. Using clever chemistry and engineering at the nanoscale, drugs can be ‘taught’ to behave like a Trojan horse, or to hold their fire until just the right moment, or to recognise the target they’re looking for.

“We always try to use techniques that can be scaled up – we avoid using expensive chemistries or expensive equipment, and we’ve been reasonably successful in that,” he adds. “By keeping costs down and using scalable techniques, we’ve got a far better chance of making a successful treatment for patients.”

In 2014, he and collaborators demonstrated that gold nanoparticles could be used to ‘smuggle’ chemotherapy drugs into cancer cells in glioblastoma multiforme, the most common and aggressive type of brain cancer in adults, which is notoriously difficult to treat. The team engineered nanostructures containing gold and cisplatin, a conventional chemotherapy drug. A coating on the particles made them attracted to tumour cells from glioblastoma patients, so that the nanostructures bound and were absorbed into the cancer cells.

Once inside, these nanostructures were exposed to radiotherapy. This caused the gold to release electrons that damaged the cancer cell’s DNA and its overall structure, enhancing the impact of the chemotherapy drug. The process was so effective that 20 days later, the cell culture showed no evidence of any revival, suggesting that the tumour cells had been destroyed.

While the technique is still several years away from use in humans, tests have begun in mice. Welland’s group is working with MedImmune, the biologics R&D arm of pharmaceutical company AstraZeneca, to study the stability of drugs and to design ways to deliver them more effectively using nanotechnology.

“One of the great advantages of working with MedImmune is they understand precisely what the requirements are for a drug to be approved. We would shut down lines of research where we thought it was never going to get to the point of approval by the regulators,” says Welland. “It’s important to be pragmatic about it so that only the approaches with the best chance of working in patients are taken forward.”

The researchers are also targeting diseases like tuberculosis (TB). With funding from the Rosetrees Trust, Welland and postdoctoral researcher Dr Íris da luz Batalha are working with Professor Andres Floto in the Department of Medicine to improve the efficacy of TB drugs.

Their solution has been to design and develop nontoxic, biodegradable polymers that can be ‘fused’ with TB drug molecules. As polymer molecules have a long, chain-like shape, drugs can be attached along the length of the polymer backbone, meaning that very large amounts of the drug can be loaded onto each polymer molecule. The polymers are stable in the bloodstream and release the drugs they carry when they reach the target cell. Inside the cell, the pH drops, which causes the polymer to release the drug.

In fact, the polymers worked so well for TB drugs that another of Welland’s postdoctoral researchers, Dr Myriam Ouberaï, has formed a start-up company, Spirea, which is raising funding to develop the polymers for use with oncology drugs. Ouberaï is hoping to establish a collaboration with a pharma company in the next two years.

“Designing these particles, loading them with drugs and making them clever so that they release their cargo in a controlled and precise way: it’s quite a technical challenge,” adds Welland. “The main reason I’m interested in the challenge is I want to see something working in the clinic – I want to see something working in patients.”

Could nanotechnology move beyond therapeutics to a time when nanomachines keep us healthy by patrolling, monitoring and repairing the body?

Nanomachines have long been a dream of scientists and public alike. But working out how to make them move has meant they’ve remained in the realm of science fiction.

But last year, Professor Jeremy Baumberg and colleagues in Cambridge and the University of Bath developed the world’s tiniest engine – just a few billionths of a metre [nanometre] in size. It’s biocompatible, cost-effective to manufacture, fast to respond and energy efficient.

The forces exerted by these ‘ANTs’ (for ‘actuating nano-transducers’) are nearly a hundred times larger than those for any known device, motor or muscle. To make them, tiny charged particles of gold, bound together with a temperature-responsive polymer gel, are heated with a laser. As the polymer coatings expel water from the gel and collapse, a large amount of elastic energy is stored in a fraction of a second. On cooling, the particles spring apart and release energy.

The researchers hope to use this ability of ANTs to produce very large forces relative to their weight to develop three-dimensional machines that swim, have pumps that take on fluid to sense the environment and are small enough to move around our bloodstream.

Working with Cambridge Enterprise, the University’s commercialisation arm, the team in Cambridge’s Nanophotonics Centre hopes to commercialise the technology for microfluidics bio-applications. The work is funded by the Engineering and Physical Sciences Research Council and the European Research Council.

“There’s a revolution happening in personalised healthcare, and for that we need sensors not just on the outside but on the inside,” explains Baumberg, who leads an interdisciplinary Strategic Research Network and Doctoral Training Centre focused on nanoscience and nanotechnology.

“Nanoscience is driving this. We are now building technology that allows us to even imagine these futures.”

I have featured Welland and his work here before and noted his penchant for wanting to insert nanodevices into humans as per this excerpt from an April 30, 2010 posting,
Getting back to the Cambridge University video, do go and watch it on the Nanowerk site. It is fun and very informative and approximately 17 mins. I noticed that they reused part of their Nokia morph animation (last mentioned on this blog here) and offered some thoughts from Professor Mark Welland, the team leader on that project. Interestingly, Welland was talking about yet another possibility. (Sometimes I think nano goes too far!) He was suggesting that we could have chips/devices in our brains that would allow us to think about phoning someone and an immediate connection would be made to that person. Bluntly—no. Just think what would happen if the marketers got access and I don’t even want to think what a person who suffers psychotic breaks (i.e., hearing voices) would do with even more input. Welland starts to talk at the 11 minute mark (I think). For an alternative take on the video and more details, visit Dexter Johnson’s blog, Nanoclast, for this posting. Hint, he likes the idea of a phone in the brain much better than I do.

I’m not sure what could have occasioned this latest press release and related video featuring Welland and nanotherapeutics other than guessing that it was a slow news period.

Curcumin: a scientific literature review concludes health benefits may be overstated

Given the number of times I’ve featured ‘curcumin research’, it seems only right to include this latest work. A Jan. 11, 2017 American Chemical Society (ACS) news release (also on EurekAlert) describes the results of a review of the scientific literature on curcumin’s (a constituent of turmeric) medicinal effectiveness,

Curcumin, a compound in turmeric, continues to be hailed as a natural treatment for a wide range of health conditions, including cancer and Alzheimer’s disease. But a new review of the scientific literature on curcumin has found it’s probably not all it’s ground up to be. The report in ACS’ Journal of Medicinal Chemistry instead cites evidence that, contrary to numerous reports, the compound has limited — if any — therapeutic benefit.

Turmeric, a spice often added to curries and mustards because of its distinct flavor and color, has been used for centuries in traditional medicine. Since the early 1990’s, scientists have zeroed in on curcumin, which makes up about 3 to 5 percent of turmeric, as the potential constituent that might give turmeric its health-boosting properties. More than 120 clinical trials to test these claims have been or are in the process of being run by clinical investigators. To get to the root of curcumin’s essential medicinal chemistry, the research groups of Michael A. Walters and Guido F. Pauli teamed up to extract key findings from thousands of scientific articles on the topic.

The researchers’ review of the vast curcumin literature provides evidence that curcumin is unstable under physiological conditions and not readily absorbed by the body, properties that make it a poor therapeutic candidate. Additionally, they could find no evidence of a double-blind, placebo-controlled clinical trial on curcumin to support its status as a potential cure-all. But, the authors say, this doesn’t necessarily mean research on turmeric should halt [emphasis mine]. Turmeric extracts and preparations could have health benefits, although probably not for the number of conditions currently touted. The researchers suggest that future studies should take a more holistic approach to account for the spice’s chemically diverse constituents that may synergistically contribute to its potential benefits.

Here’s a link to and citation for the paper,

The Essential Medicinal Chemistry of Curcumin by Kathryn M. Nelson, Jayme L. Dahlin, Jonathan Bisson, James Graham, Guido F. Pauli, and Michael A. Walters. J. Med. Chem., Article ASAP DOI: 10.1021/acs.jmedchem.6b00975 Publication Date (Web): January 11, 2017

Copyright © 2017 American Chemical Society

This paper is open access.

Sniffing out disease (Na-Nose)

The ‘artificial nose’ is not a newcomer to this blog. The most recent post prior to this is a March 15, 2016 piece about Disney using an artificial nose for art conservation. Today’s (Jan. 9, 2016) piece concerns itself with work from Israel and ‘sniffing out’ disease, according to a Dec. 30, 2016 news item in Sputnik News,

A team from the Israel Institute of Technology has developed a device that from a single breath can identify diseases such as multiple forms of cancer, Parkinson’s disease, and multiple sclerosis. While the machine is still in the experimental stages, it has a high degree of promise for use in non-invasive diagnoses of serious illnesses.

The international team demonstrated that a medical theory first proposed by the Greek physician Hippocrates some 2400 years ago is true, certain diseases leave a “breathprint” on the exhalations of those afflicted. The researchers created a prototype for a machine that can pick up on those diseases using the outgoing breath of a patient. The machine, called the Na-Nose, tests breath samples for the presence of trace amounts of chemicals that are indicative of 17 different illnesses.

A Dec. 22, 2016 Technion Israel Institute of Technology press release offers more detail about the work,

An international team of 56 researchers in five countries has confirmed a hypothesis first proposed by the ancient Greeks – that different diseases are characterized by different “chemical signatures” identifiable in breath samples. …

Diagnostic techniques based on breath samples have been demonstrated in the past, but until now, there has not been scientific proof of the hypothesis that different and unrelated diseases are characterized by distinct chemical breath signatures. And technologies developed to date for this type of diagnosis have been limited to detecting a small number of clinical disorders, without differentiation between unrelated diseases.

The study of more than 1,400 patients included 17 different and unrelated diseases: lung cancer, colorectal cancer, head and neck cancer, ovarian cancer, bladder cancer, prostate cancer, kidney cancer, stomach cancer, Crohn’s disease, ulcerative colitis, irritable bowel syndrome, Parkinson’s disease (two types), multiple sclerosis, pulmonary hypertension, preeclampsia and chronic kidney disease. Samples were collected between January 2011 and June 2014 from in 14 departments at 9 medical centers in 5 countries: Israel, France, the USA, Latvia and China.

The researchers tested the chemical composition of the breath samples using an accepted analytical method (mass spectrometry), which enabled accurate quantitative detection of the chemical compounds they contained. 13 chemical components were identified, in different compositions, in all 17 of the diseases.

According to Prof. Haick, “each of these diseases is characterized by a unique fingerprint, meaning a different composition of these 13 chemical components.  Just as each of us has a unique fingerprint that distinguishes us from others, each disease has a chemical signature that distinguishes it from other diseases and from a normal state of health. These odor signatures are what enables us to identify the diseases using the technology that we developed.”

With a new technology called “artificially intelligent nanoarray,” developed by Prof. Haick, the researchers were able to corroborate the clinical efficacy of the diagnostic technology. The array enables fast and inexpensive diagnosis and classification of diseases, based on “smelling” the patient’s breath, and using artificial intelligence to analyze the data obtained from the sensors. Some of the sensors are based on layers of gold nanoscale particles and others contain a random network of carbon nanotubes coated with an organic layer for sensing and identification purposes.

The study also assessed the efficiency of the artificially intelligent nanoarray in detecting and classifying various diseases using breath signatures. To verify the reliability of the system, the team also examined the effect of various factors (such as gender, age, smoking habits and geographic location) on the sample composition, and found their effect to be negligible, and without impairment on the array’s sensitivity.

“Each of the sensors responds to a wide range of exhalation components,” explain Prof. Haick and his previous Ph.D student, Dr. Morad Nakhleh, “and integration of the information provides detailed data about the unique breath signatures characteristic of the various diseases. Our system has detected and classified various diseases with an average accuracy of 86%.

This is a new and promising direction for diagnosis and classification of diseases, which is characterized not only by considerable accuracy but also by low cost, low electricity consumption, miniaturization, comfort and the possibility of repeating the test easily.”

“Breath is an excellent raw material for diagnosis,” said Prof. Haick. “It is available without the need for invasive and unpleasant procedures, it’s not dangerous, and you can sample it again and again if necessary.”

Here’s a schematic of the study, which the researchers have made available,

Diagram: A schematic view of the study. Two breath samples were taken from each subject, one was sent for chemical mapping using mass spectrometry, and the other was analyzed in the new system, which produced a clinical diagnosis based on the chemical fingerprint of the breath sample. Courtesy: Tech;nion

There is also a video, which covers much of the same ground as the press release but also includes information about the possible use of the Na-Nose technology in the European Union’s SniffPhone project,

Here’s a link to and a citation for the paper,

Diagnosis and Classification of 17 Diseases from 1404 Subjects via Pattern Analysis of Exhaled Molecules by Morad K. Nakhleh, Haitham Amal, Raneen Jeries, Yoav Y. Broza, Manal Aboud, Alaa Gharra, Hodaya Ivgi, Salam Khatib, Shifaa Badarneh, Lior Har-Shai, Lea Glass-Marmor, Izabella Lejbkowicz, Ariel Miller, Samih Badarny, Raz Winer, John Finberg, Sylvia Cohen-Kaminsky, Frédéric Perros, David Montani, Barbara Girerd, Gilles Garcia, Gérald Simonneau, Farid Nakhoul, Shira Baram, Raed Salim, Marwan Hakim, Maayan Gruber, Ohad Ronen, Tal Marshak, Ilana Doweck, Ofer Nativ, Zaher Bahouth, Da-you Shi, Wei Zhang, Qing-ling Hua, Yue-yin Pan, Li Tao, Hu Liu, Amir Karban, Eduard Koifman, Tova Rainis, Roberts Skapars, Armands Sivins, Guntis Ancans, Inta Liepniece-Karele, Ilze Kikuste, Ieva Lasina, Ivars Tolmanis, Douglas Johnson, Stuart Z. Millstone, Jennifer Fulton, John W. Wells, Larry H. Wilf, Marc Humbert, Marcis Leja, Nir Peled, and Hossam Haick. ACS Nano, Article ASAP DOI: 10.1021/acsnano.6b04930 Publication Date (Web): December 21, 2016

Copyright © 2017 American Chemical Society

This paper appears to be open access.

As for SniffPhone, they’re hoping that Na-Nose or something like it will allow them to modify smartphones in a way that will allow diseases to be detected.

I can’t help wondering who will own the data if your smartphone detects a disease. If you think that’s an idle question, here’s an excerpt from Sue Halpern’s Dec. 22, 2016 review of two books (“Weapons of Math Destruction: How Big Data Increases Inequality and Threatens Democracy” by Cathy O’Neil and “Virtual Competition: The Promise and Perils of the Algorithm-Driven Economy” by Ariel Ezrachi and Maurice E. Stucke) for the New York Times Review of Books,

We give our data away. We give it away in drips and drops, not thinking that data brokers will collect it and sell it, let alone that it will be used against us. There are now private, unregulated DNA databases culled, in part, from DNA samples people supply to genealogical websites in pursuit of their ancestry. These samples are available online to be compared with crime scene DNA without a warrant or court order. (Police are also amassing their own DNA databases by swabbing cheeks during routine stops.) In the estimation of the Electronic Frontier Foundation, this will make it more likely that people will be implicated in crimes they did not commit.

Or consider the data from fitness trackers, like Fitbit. As reported in The Intercept:

During a 2013 FTC panel on “Connected Health and Fitness,” University of Colorado law professor Scott Peppet said, “I can paint an incredibly detailed and rich picture of who you are based on your Fitbit data,” adding, “That data is so high quality that I can do things like price insurance premiums or I could probably evaluate your credit score incredibly accurately.”

Halpern’s piece is well worth reading in its entirety.

Nanoparticle ‘caterpillars’ and immune system ‘crows’

This University of Colorado work fits in nicely with other efforts to ensure that nanoparticle medical delivery systems get to their destinations. From a Dec. 19, 2016 news item on phys.org,

In the lab, doctors can attach chemotherapy to nanoparticles that target tumors, and can use nanoparticles to enhance imaging with MRI, PET and CT scans. Unfortunately, nanoparticles look a lot like pathogens – introducing nanoparticles to the human body can lead to immune system activation in which, at best, nanoparticles are cleared before accomplishing their purpose, and at worst, the onset of dangerous allergic reaction. A University of Colorado Cancer Center paper published today [Dec. 19, 2016] in the journal Nature Nanotechnology details how the immune system recognizes nanoparticles, potentially paving the way to counteract or avoid this detection.

Specifically, the study worked with dextran-coated iron oxide nanoparticles, a promising and versatile class of particles used as drug-delivery vehicles and MRI contrast enhancers in many studies. As their name implies, the particles are tiny flecks of iron oxide encrusted with sugar chains.

“We used several sophisticated microscopy approaches to understand that the particles basically look like caterpillars,” says Dmitri Simberg, PhD, investigator at the CU Cancer Center and assistant professor in the Skaggs School of Pharmacy and Pharmaceutical Sciences, the paper’s senior author.

The comparison is striking: the iron oxide particle is the caterpillar’s body, which is surrounded by fine hairs of dextran.

Caption: University of Colorado Cancer Study shows how nanoparticles activate the complement system, potentially paving the way for expanded use of these technologies.
Credit: University of Colorado Cancer Center

A Dec. 19, 2016 University of Colorado news release on EurekAlert, which originated the news item, describes the work in more detail,

If Simberg’s dextran-coated iron oxide nanoparticles are caterpillars, then the immune system is a fat crow that would eat them – that is, if it can find them. In fact, the immune system has evolved for exactly this purpose – to find and “eat” foreign particles – and rather than one homogenous entity is actually composed of a handful of interrelated systems, each specialized to counteract a specific form of invading particle.

Simberg’s previous work shows that it is the immune subcomponent called the complement system that most challenges nanoparticles. Basically, the complement system is a group of just over 30 proteins that circulate through the blood and attach to invading particles and pathogens. In humans, complement system activation requires that three proteins come together on a particle -C3b, Bb and properdin – which form a stable complex called C3-convertase.

“The whole complement system activation starts with the assembly of C3-convertase,” Simberg says. “In this paper, we ask the question of how the complement proteins actually recognize the nanoparticle surface. How is this whole reaction triggered?”

First, it was clear that the dextran coating that was supposed to protect the nanoparticles from human complement attack was not doing its job. Simberg and colleagues could see complement proteins literally invade the barrier of dextran hairs.

“Electron microscopy images show protein getting inside the particle to touch the iron oxide core,” Simberg says.

In fact, as long as the nanoparticle coating allowed the nanoparticle to absorb proteins from blood, the C3 convertase was assembled and activated on these proteins. The composition of the coating was irrelevant – if any blood protein was able to bind to nanoparticles, it always led to complement activation. Moreover, Simberg and colleagues also showed that complement system activation is a dynamic and ongoing process – blood proteins and C3 convertase constantly dissociate from nanoparticles, and new proteins and C3 convertases bind to the particles, continuing the cascade of immune system activation. The group also demonstrated that this dynamic assembly of complement proteins occurs not only in the test tubes but also in living organisms as particles circulate in blood.

Simberg suggests that the work points to challenges and three possible strategies to avoid complement system activation by nanoparticles: “First, we could try to change the nanoparticle coating so that it can’t absorb proteins, which is a difficult task; second, we could better understand the composition of proteins absorbed from blood on the particle surface that allow it to bind complement proteins; and third, there are natural inhibitors of complement activation – for example blood Factor H – but in the context of nanoparticles, it’s not strong enough to stop complement activation. Perhaps we could get nanoparticles to attract more Factor H to decrease this activation.”

At one point, the concept of nanomedicine seemed as if it would be simple – engineers and chemists would make a nanoparticle with affinity for tumor tissue and then attach a drug molecule to it. Or they would inject nanoparticles into patients that would improve the resolution of diagnostic imaging. When the realities associated with the use of nanoparticles in the landscape of the human immune system proved more challenging, many researchers realized the need to step back from possible clinical use to better understand the mechanisms that challenge nanoparticle use.

“This basic groundwork is absolutely necessary,” says Seyed Moein Moghimi, PhD, nanotechnologist at Durham University, UK, and the coauthor of the Simberg paper. “It’s essential that we learn to control the process of immune recognition so that we can bridge between the promise that nanoparticles demonstrate in the lab and their use with real patients in the real world.”

Here’s a link to and a citation for the paper,

Complement proteins bind to nanoparticle protein corona and undergo dynamic exchange in vivo by Fangfang Chen, Guankui Wang, James I. Griffin, Barbara Brenneman, Nirmal K. Banda, V. Michael Holers, Donald S. Backos, LinPing Wu, Seyed Moein Moghimi, & Dmitri Simberg. Nature Nanotechnology  (2016) doi:10.1038/nnano.2016.269 19 December 2016

This paper is behind a paywall.

I have a few previous postings about nanoparticles as drug delivery systems which have yet to fulfill their promise. There’s the April 27, 2016 posting (How many nanoparticle-based drugs does it take to kill a cancer tumour? More than 1%) and the Sept. 9, 2016 posting (Discovering how the liver prevents nanoparticles from reaching cancer cells).

Liquid biopsy chip that uses carbon nanotubes in place of microfluidics

They’re calling this a breakthrough technology in a Dec. 15, 2016 news item on ScienceDaily,

A chip developed by mechanical engineers at Worcester Polytechnic Institute (WPI) [UK] can trap and identify metastatic cancer cells in a small amount of blood drawn from a cancer patient. The breakthrough technology uses a simple mechanical method that has been shown to be more effective in trapping cancer cells than the microfluidic approach employed in many existing devices.

The WPI device uses antibodies attached to an array of carbon nanotubes at the bottom of a tiny well. Cancer cells settle to the bottom of the well, where they selectively bind to the antibodies based on their surface markers (unlike other devices, the chip can also trap tiny structures called exosomes produced by cancers cells). This “liquid biopsy,” described in a recent issue of the journal Nanotechnology, could become the basis of a simple lab test that could quickly detect early signs of metastasis and help physicians select treatments targeted at the specific cancer cells identified.

A Dec. 15, 2016 WPI press release (also on EurekAlert), which originated the news item, explains the breakthrough in more detail (Note: Links have been removed),

Metastasis is the process by which a cancer can spread from one organ to other parts of the body, typically by entering the bloodstream. Different types of tumors show a preference for specific organs and tissues; circulating breast cancer cells, for example, are likely to take root in bones, lungs, and the brain. The prognosis for metastatic cancer (also called stage IV cancer) is generally poor, so a technique that could detect these circulating tumor cells before they have a chance to form new colonies of tumors at distant sites could greatly increase a patient’s survival odds.

“The focus on capturing circulating tumor cells is quite new,” said Balaji Panchapakesan, associate professor of mechanical engineering at WPI and director of the Small Systems Laboratory. “It is a very difficult challenge, not unlike looking for a needle in a haystack. There are billions of red blood cells, tens of thousands of white blood cells, and, perhaps, only a small number of tumor cells floating among them. We’ve shown how those cells can be captured with high precision.”

The device developed by Panchapakesan’s team includes an array of tiny elements, each about a tenth of an inch (3 millimeters) across. Each element has a well, at the bottom of which are antibodies attached to carbon nanotubes. Each well holds a specific antibody that will bind selectively to one type of cancer cell type, based on genetic markers on its surface. By seeding elements with an assortment of antibodies, the device could be set up to capture several different cancer cells types using a single blood sample. In the lab, the researchers were able to fill a total of 170 wells using just under 0.3 fluid ounces (0.85 milliliter) of blood. Even with that small sample, they captured between one and a thousand cells per device, with a capture efficiency of between 62 and 100 percent.

In a paper published in the journal Nanotechnology [“Static micro-array isolation, dynamic time series classification, capture and enumeration of spiked breast cancer cells in blood: the nanotube–CTC chip”], Panchapakesan’s team, which includes postdoctoral researcher Farhad Khosravi, the paper’s lead author, and researchers at the University of Louisville and Thomas Jefferson University, describe a study in which antibodies specific for two markers of metastatic breast cancer, EpCam and Her2, were attached to the carbon nanotubes in the chip. When a blood sample that had been “spiked” with cells expressing those markers was placed on the chip, the device was shown to reliably capture only the marked cells.

In addition to capturing tumor cells, Panchapakesan says the chip will also latch on to tiny structures called exosomes, which are produced by cancers [sic] cells and carry the same markers. “These highly elusive 3-nanometer structures are too small to be captured with other types of liquid biopsy devices, such as microfluidics, due to shear forces that can potentially destroy them,” he noted. “Our chip is currently the only device that can potentially capture circulating tumor cells and exosomes directly on the chip, which should increase its ability to detect metastasis. This can be important because emerging evidence suggests that tiny proteins excreted with exosomes can drive reactions that may become major barriers to effective cancer drug delivery and treatment.”

Panchapakesan said the chip developed by his team has additional advantages over other liquid biopsy devices, most of which use microfluidics to capture cancer cells. In addition to being able to capture circulating tumor cells far more efficiently than microfluidic chips (in which cells must latch onto anchored antibodies as they pass by in a stream of moving liquid), the WPI device is also highly effective in separating cancer cells from the other cells and material in the blood through differential settling.

While the initial tests with the chip have focused on breast cancer, Panchapakesan says the device could be set up to detect a wide range of tumor types, and plans are already in the works for development of an advanced device as well as testing for other cancer types, including lung and pancreas cancer. He says he envisions a day when a device like his could be employed not only for regular follow ups for patients who have had cancer, but in routine cancer screening.

“Imagine going to the doctor for your yearly physical,” he said. “You have blood drawn and that one blood sample can be tested for a comprehensive array of cancer cell markers. Cancers would be caught at their earliest stage and other stages of development, and doctors would have the necessary protein or genetic information from these captured cells to customize your treatment based on the specific markers for your cancer. This would really be a way to put your health in your own hands.”

“White blood cells, in particular, are a problem, because they are quite numerous in blood and they can be mistaken for cancer cells,” he said. “Our device uses what is called a passive leukocyte depletion strategy. Because of density differences, the cancer cells tend to settle to the bottom of the wells (and this only happens in a narrow window), where they encounter the antibodies. The remainder of the blood contents stays at the top of the wells and can simply be washed away.”

Here’s a link to and a citation for the paper,

Static micro-array isolation, dynamic time series classification, capture and enumeration of spiked breast cancer cells in blood: the nanotube–CTC chip by Farhad Khosravi, Patrick J Trainor, Christopher Lambert, Goetz Kloecker, Eric Wickstrom, Shesh N Rai, and Balaji Panchapakesan. Nanotechnology, Volume 27, Number 44 DOI http://dx.doi.org/10.1088/0957-4484/27/44/44LT03 Published 29 September 2016

© 2016 IOP Publishing Ltd

This paper is open access.

A ‘vascular running of the bulls’; nanoparticles in your bloodstream

An Oct. 5, 2016 news item on phys.org announces research into how nanoparticles behave in the bloodstream (Note: A link has been removed),

Researchers at the University of Connecticut have uncovered new information about how particles behave in our bloodstream, an important advancement that could help pharmaceutical scientists develop more effective cancer drugs.

Making sure cancer medications reach the leaky blood vessels surrounding most tumor sites is one of the critical aspects of treatment and drug delivery. While surface chemistry, molecular interactions, and other factors come into play once drug-carrying particles arrive at a tumor, therapeutic medication doesn’t do very much good if it never reaches its intended target.

Anson Ma, an assistant professor of chemical and biomolecular engineering at UConn, used a microfluidic channel device to observe, track, and measure how individual particles behaved in a simulated blood vessel.

The research team’s goal: to learn more about the physics influencing a particle’s behavior as it travels in our blood and to determine which particle size might be the most effective for delivering drugs to their targets. The team’s experimental findings mark the first time such quantitative data has been gathered. …

“Even before particles reach a target site, you have to worry about what is going to happen with them after they get injected into the bloodstream,” Ma says. “Are they going to clump together? How are they going to move around? Are they going to get swept away and flushed out of our bodies?”

Using a high-powered fluorescence microscope in UConn’s Complex Fluids Lab, Ma was able to observe particles being carried along in the simulated blood vessel in what could be described as a vascular Running of the Bulls [emphasis mine]. Red blood cells race through the middle of the channel as the particles – highlighted under the fluorescent light – get carried along in the rush, bumping and bouncing off the blood cells until they are pushed to open spaces – called the cell-free layer – along the vessel’s walls.

Nanocarrier particles injected into the bloodstream bounce off red and white blood cells and platelets, and are pushed toward the blood vessel walls. This physical interaction, measured and quantified for the first time by engineering professor Anson Ma’s lab, provides important information for drug developers. (Image courtesy of Anson Ma)

Nanocarrier particles injected into the bloodstream bounce off red and white blood cells and platelets, and are pushed toward the blood vessel walls. This physical interaction, measured and quantified for the first time by engineering professor Anson Ma’s lab, provides important information for drug developers. (Image courtesy of Anson Ma)

An Oct. 4, 2016 University of Connecticut news release, which originated the news item, provides more detail about the research,

What Ma found was that larger particles – the optimum size appeared to be about 2 microns – were most likely to get pushed to the cell-free layer, where their chances of carrying medication into a tumor site are greatest. The research team also determined that 2 microns was the largest size that should be used if particles are going to have any chance of going through the leaky blood vessel walls into the tumor site.

“When it comes to using particles for the delivery of cancer drugs, size matters,” Ma says. “When you have a bigger particle, the chance of it bumping into blood cells is much higher, there are a lot more collisions, and they tend to get pushed to the blood vessel walls.”

The results were somewhat surprising. In preparing their hypothesis, the research team estimated that smaller particles were probably the most effective since they would move the most in collisions with blood cells, much like what happens when a small ball bounces off a larger one. But just the opposite proved true. The smaller particles appeared to skirt through the mass of moving blood cells and were less likely to experience the “trampoline” effect and get bounced to the cell-free layer, says Ma.

Ma proposed the study after talking to a UConn pharmaceutical scientist about drug development at a campus event five years ago.

“We had a great conversation about how drugs are made and then I asked, ‘But how can you be sure where the particles go?’” Ma recalls, laughing. “I’m an engineer. That’s how we think. I was curious. This was an engineering question. So I said, ‘Let’s write a proposal!’”

The proposal was funded by the National Science Foundation’s Early-concept Grants for Exploratory Research or EAGER program, which supports exploratory work in its early stages on untested, but potentially transformative, research ideas or approaches.

Knowing how particles behave in our circulatory system should help improve targeted drug delivery, Ma says, which in turn will further reduce the toxic side effects caused by potent cancer drugs missing their target and impacting the body’s healthy tissue.

The findings were particularly meaningful for Ma, who lost two of his grandparents to cancer and who has long wanted to contribute to cancer research in a meaningful way as an engineer.

Measuring how particles of different sizes move in the bloodstream may also be beneficial in bioimaging, where scientists and doctors want to keep particles circulating in the bloodstream long enough for imaging to occur. In that case, smaller particles would be better, says Ma.

Moving forward, Ma would like to explore other aspects of particle flow in our circulatory system, such as how particles behave when they pass through a constricted area, such as from a blood vessel to a capillary. Capillaries are only about 7 microns in diameter. The average human hair is 100 microns.  Ma says he would like to know how that constricted space might impact particle flow or the ability of particles to accumulate near the vessel walls.

“We have all of this complex geometry in our bodies,” says Ma. “Most people just assume there is no impact when a particle moves from a bigger channel to a smaller channel because they haven’t quantified it. Our plan is to do some experiments to look at this more carefully, building on the work that we just published.”

Here’s a link to and a citation for the paper,

Direct Tracking of Particles and Quantification of Margination in Blood Flow by Erik J. Carbon, Brice H. Bognet, Grant M. Bouchillon, Andrea L. Kadilak, Leslie M. Shor, Michael D. Ward, Anson W.K. Ma. Biophysical Journal Volume 111, Issue 7, p1487–1495, 4 October 2016  DOI: http://dx.doi.org/10.1016/j.bpj.2016.08.026

This paper is behind a paywall.

Discovering how the liver prevents nanoparticles from reaching cancer cells

There’s a lot of excitement about nanoparticles as enabling a precise drug delivery system but to date results have been disappointing as a team of researchers at the University of Toronto (Canada) noted recently (see my April 27, 2016 posting). According to those researchers, one of the main problems with the proposed nanoparticle drug delivery system is that we don’t understand how the body delivers materials to cells and disappointingly few nanoparticles (less than 1%) make their way to tumours. That situation may be changing.

An Aug. 19, 2016 news item on Nanowerk announces the latest research from the University of Toronto,

The emerging field of nanomedicine holds great promise in the battle against cancer. Particles the size of protein molecules can be customized to carry tumour-targeting drugs and destroy cancer cells without harming healthy tissue.

But here’s the problem: when nanoparticles are administered into the body, more than 99 per cent of them become trapped in non-targeted organs, such as the liver and spleen. These nanoparticles are not delivered to the site of action to carry out their intended function.

To solve this problem, researchers at the University of Toronto and the University Health Network have figured out how the liver and spleen trap intact nanoparticles as they move through the organ. “If you want to unlock the promise of nanoparticles, you have to understand and solve the problem of the liver,” says Dr. Ian McGilvray, a transplant surgeon at the Toronto General Hospital and scientist at the Toronto General Research Institute (TGRI).

An Aug. 15, 2016 University of Toronto news release by Luke Ng, which originated the news item, expands on the theme,

In a recent paper in the journal Nature Materials, the researchers say that as nanoparticles move through the liver sinusoid, the flow rate slows down 1,000 times, which increases the interaction of the nanoparticles all of types of liver cells. This was a surprising finding because the current thought is that Kupffer cells, responsible for toxin breakdown in the liver, are the ones that gobbles [sic] up the particles.  This study found that liver B-cells and liver sinusoidal endothelial cells are also involved and that the cell phenotype also matters.

“We know that the liver is the principle organ controlling what gets absorbed by our bodies and what gets filtered out—it governs our everyday biological functions,” says Dr. Kim Tsoi (… [and] research partner Sonya MacParland), a U of T orthopaedic surgery resident, and a first author of the paper, who completed her PhD in biomedical engineering with Warren Chan (IBBME). “But nanoparticle drug delivery is a newer approach and we haven’t had a clear picture of how they interact with the liver—until now.”

Tsoi and MacParland first examined both the speed and location of their engineered nanoparticles as they moved through the liver.

“This gives us a target to focus on,” says MacParland, an immunology post-doctoral fellow at U of T and TGRI. “Knowing the specific cells to modify will allow us to eventually deliver more of the nanoparticles to their intended target, attacking only the pathogens or tumours, while bypassing healthy cells.”

“Many prior studies that have tried to reduce nanomaterial clearance in the liver have focused on the particle design itself,” says Chan. “But our work now gives greater insight into the biological mechanisms underpinning our experimental observations — now we hope to use our fundamental findings to help design nanoparticles that work with the body, rather than against it.”

Here’s a link to and a citation for the paper,

Mechanism of hard-nanomaterial clearance by the liver by Kim M. Tsoi, Sonya A. MacParland, Xue-Zhong Ma, Vinzent N. Spetzler, Juan Echeverri, Ben Ouyang, Saleh M. Fadel, Edward A. Sykes, Nicolas Goldaracena, Johann M. Kaths, John B. Conneely, Benjamin A. Alman, Markus Selzner, Mario A. Ostrowski, Oyedele A. Adeyi, Anton Zilman, Ian D. McGilvray, & Warren C. W. Chan. Nature Materials (2016) doi:10.1038/nmat4718 Published online 15 August 2016

This paper is behind a paywall.

pH dependent nanoparticle-based contrast agent for MRIs (magnetic resonance images)

This news about a safer and more effective contrast agent for MRIs (magnetic resonance images) developed by Japanese scientists come from a June 6, 2016 article by Heather Zeiger on phys.org. First some explanations,

Magnetic resonance imaging relies on the excitation and subsequent relaxation of protons. In clinical MRI studies, the signal is determined by the relaxation time of the hydrogen protons in water. To get a stronger signal, scientists can use contrast agents to shorten the relaxation time of the protons.

MRI is non-invasive and does not involve radiation, making it a safe diagnostic tool. However, its weak signal makes tumor detection difficult. The ideal contrast agent would select for malignant tumors, making its location and diagnosis much more obvious.

Nanoparticle contrast agents have been of interested because nanoparticles can be functionalized and, as in this study, can contain various metals. Researchers have attempted to functionalize nanoparticles with ligands that attach to chemical factors on the surface of cancer cells. However, cancer cells tend to be compositionally heterogeneous, leading some researchers to look for nanoparticles that respond to differences in pH or redox potential compared to normal cells.

Now for the research,

Researchers from the University of Tokyo, Tokyo Institute of Technology, Kawasaki Institute of Industry Promotion, and the Japan Agency for Quantum and Radiological Science and Technology have developed a contrast agent from calcium phosphate-based nanoparticles that release a manganese ion an acidic environment. …

Peng Mi, Daisuke Kokuryo, Horacio Cabral, Hailiang Wu, Yasuko Terada, Tsuneo Saga, Ichio Aoki, Nobuhiro Nishiyama, and Kazunori Kataoka developed a contrast agent that is comprised of Mn2+– doped CaP nanoparticles with a PEG shell. They reasoned that using CaP nanoparticles, which are known to be pH sensitive, would allow the targeted release of Mn2+ ions in the tumor microenvironment. The tumor microenvironment tends to have a lower pH than the normal regions to rapid cell metabolism in an oxygen-depleted environment. Manganese ions were tested because they are paramagnetic, which makes for a good contrast agent. They also bind to proteins creating a slowly rotating manganese-protein system that results in sharp contrast enhancement.

These results were promising, so Peng Mi, et al. then tested whether the CaPMnPEG contrast agent worked in solid tumors. Because Mn2+ remains confined within the nanoparticle matrix at physiological pH, CaPMnPEG demonstrate a much lower toxicity [emphasis mine] compared to MnCl2. MRI studies showed a tumor-to-normal contrast of 131% after 30 minute, which is much higher than Gd-DTPA [emphasis mine], a clinically approved contrast agent. After an hour, the tumor-to-normal ratio was 160% and remained around 170% for several hours.

Three-dimensional MRI studies of solid tumors showed that without the addition of CaPMnPEG, only blood vessels were visible. However, upon adding CaPMnPEG, the tumor was easily distinguishable. Additionally, there is evidence that excess Mn2+ leaves the plasma after an hour. The contrast signal remained strong for several hours indicating that protein binding rather than Mn2+ concentration is important for signal enhancement.

Finally, tests with metastatic tumors in the liver (C26 colon cancer cells) showed that CaPMnPEG works well in solid organ analysis and is highly sensitive to detecting millimeter-sized micrometastasis [emphasis mine]. Unlike other contrast agents used in the clinic, CaPMnPEG provided a contrast signal that lasted for several hours after injection. After an hour, the signal was enhanced by 25% and after two hours, the signal was enhanced by 39%.

This is exciting stuff. Bravo to the researchers!

Here’s a link to and citation for the paper,

A pH-activatable nanoparticle with signal-amplification capabilities for non-invasive imaging of tumour malignancy by Peng Mi, Daisuke Kokuryo, Horacio Cabral, Hailiang Wu, Yasuko Terada, Tsuneo Saga, Ichio Aoki, Nobuhiro Nishiyama, & Kazunori Kataoka. Nature Nanotechnology (2016) doi:10.1038/nnano.2016.72 Published online 16 May 2016

This paper is behind a paywall.