Microneedle Patch Delivers Localized Cancer Immunotherapy to Melanoma

Biomedical engineering researchers at North Carolina State University and the University of North Carolina at Chapel Hill have developed a technique that uses a patch embedded with microneedles to deliver cancer immunotherapy treatment directly to the site of melanoma skin cancer. In animal studies, the technique more effectively targeted melanoma than other immunotherapy treatments.

According to the CDC, more than 67,000 people in the United States were diagnosed with melanoma in 2012 alone – the most recent year for which data are available. If caught early, melanoma patients have a 5-year survival rate of more than 98 percent, according to the National Cancer Institute. That number dips to 16.6 percent if the cancer has metastasized before diagnosis and treatment. Melanoma treatments range from surgery to chemotherapy and radiation therapy. A promising new field of cancer treatment is cancer immunotherapy, which helps the body’s own immune system fight off cancer.

In the immune system, T cells are supposed to identify and kill cancer cells. To do their job, T cells use specialized receptors to differentiate healthy cells from cancer cells. But cancer cells can trick T cells. One way cancer cells do this is by expressing a protein ligand that binds to a receptor on the T cells to prevent the T cell from recognizing and attacking the cancer cell.

Recently, cancer immunotherapy research has focused on using “anti-PD-1” (or programmed cell death) antibodies to prevent cancer cells from tricking T cells.

“However, this poses several challenges,” says Chao Wang, co-lead author of a paper on the microneedle research and a postdoctoral researcher in the joint biomedical engineering program at NC State and UNC-Chapel Hill. “First, the anti-PD-1 antibodies are usually injected into the bloodstream, so they cannot target the tumor site effectively. Second, the overdose of antibodies can cause side effects such as an autoimmune disorder.”

To address these challenges, the researchers developed a patch that uses microneedles to deliver anti-PD-1 antibodies locally to the skin tumor. The microneedles are made from hyaluronic acid, a biocompatible material.

The anti-PD-1 antibodies are embedded in nanoparticles, along with glucose oxidase – an enzyme that produces acid when it comes into contact with glucose. These nanoparticles are then loaded into microneedles, which are arrayed on the surface of a patch.

When the patch is applied to a melanoma, blood enters the microneedles. The glucose in the blood makes the glucose oxidase produce acid, which slowly breaks down the nanoparticles. As the nanoparticles degrade, the anti-PD-1 antibodies are released into the tumor.

“This technique creates a steady, sustained release of antibodies directly into the tumor site; it is an efficient approach with enhanced retention of anti-PD-1 antibodies in the tumor microenvironment,” says Zhen Gu, an assistant professor in the biomedical engineering program and senior author of the paper.

The researchers tested the technique against melanoma in a mouse model. The microneedle patch loaded with anti-PD-1 nanoparticles was compared to treatment by injecting anti-PD-1 antibodies directly into the bloodstream and to injecting anti-PD-1 nanoparticles directly into the tumor.

“After 40 days, 40 percent of the mice who were treated using the microneedle patch survived and had no detectable remaining melanoma – compared to a zero percent survival rate for the control groups,” says Yanqi Ye, a Ph.D. student in Gu’s lab and co-lead author of the paper.

The researchers also created a drug cocktail, consisting of anti-PD-1 antibodies and another antibody called anti-CTLA-4 – which also helps T cells attack the cancer cells.

“Using a combination of anti-PD-1 and anti-CTLA-4 in the microneedle patch, 70 percent of the mice survived and had no detectable melanoma after 40 days,” Wang says.

“Because of the sustained and localized release manner, mediated by microneedles, we are able to achieve desirable therapeutic effects with a relatively low dosage, which reduces the risk of auto-immune disorders,” Gu says.

“We’re excited about this technique, and are seeking funding to pursue further studies and potential clinical translation,” Gu adds.

The paper, “Enhanced Cancer Immunotherapy by Microneedle Patch-Assisted Delivery of Anti-PD-1 Antibody,” is published in the journal Nano Letters. The paper was co-authored by Gabrielle Hochu, an undergraduate in the biomedical engineering program, and Hasan Sadeghifa, a postdoctoral researcher at NC State. The work was supported by NC TraCS, NIH’s Clinical and Translational Science Awards at UNC-Chapel Hill, under grant number 1UL1TR001111.

Reference

“Enhanced Cancer Immunotherapy by Microneedle Patch-Assisted Delivery of Anti-PD1 Antibody”

Authors: Chao Wang, Yanqi Ye, Gabrielle M. Hochu, and Zhen Gu, North Carolina State University and the University of North Carolina at Chapel Hill; Hasan Sadeghifa, North Carolina State University

Published: March 21, Nano Letters - DOI: 10.1021/acs.nanolett.5b05030

Nanotechnology World Association

Sensors slip into the brain, then dissolve when the job is done

A team of neurosurgeons and engineers has developed wireless brain sensors that monitor intracranial pressure and temperature and then are absorbed by the body, negating the need for surgery to remove the devices.

Such implants, developed by scientists at Washington University School of Medicine in St. Louis and engineers at the University of Illinois at Urbana-Champaign, potentially could be used to monitor patients with traumatic brain injuries, but the researchers believe they can build similar absorbable sensors to monitor activity in organ systems throughout the body. Their findings are published online Jan. 18 in the journal Nature.

"Electronic devices and their biomedical applications are advancing rapidly," said co-first author Rory K. J. Murphy, MD, a neurosurgery resident at Washington University School of Medicine and Barnes-Jewish Hospital in St. Louis. "But a major hurdle has been that implants placed in the body often trigger an immune response, which can be problematic for patients. The benefit of these new devices is that they dissolve over time, so you don't have something in the body for a long time period, increasing the risk of infection, chronic inflammation and even erosion through the skin or the organ in which it's placed. Plus, using resorbable devices negates the need for surgery to retrieve them, which further lessens the risk of infection and further complications."

Murphy is most interested in monitoring pressure and temperature in the brains of patients with traumatic brain injury.

About 50,000 people die of such injuries annually in the United States. When patients with such injuries arrive in the hospital, doctors must be able to accurately measure intracranial pressure in the brain and inside the skull because an increase in pressure can lead to further brain injury, and there is no way to reliably estimate pressure levels from brain scans or clinical features in patients.

"However, the devices commonly used today are based on technology from the 1980s," Murphy explained. "They're large, they're unwieldy, and they have wires that connect to monitors in the intensive care unit. They give accurate readings, and they help, but there are ways to make them better."

Murphy collaborated with engineers in the laboratory of John A. Rogers, PhD, a professor of materials science and engineering at the University of Illinois, to build new sensors. The devices are made mainly of polylactic-co-glycolic acid (PLGA) and silicone, and they can transmit accurate pressure and temperature readings, as well as other information.

"With advanced materials and device designs, we demonstrated that it is possible to create electronic implants that offer high performance and clinically relevant operation in hardware that completely resorbs into the body after the relevant functions are no longer needed," Rogers said. "This type of bio-electric medicine has great potential in many areas of clinical care."

The researchers tested the sensors in baths of saline solution that caused them to dissolve after a few days. Next, they tested the devices in the brains of laboratory rats.

Having shown that the sensors are accurate and that they dissolve in the solution and in the brains of rats, the researchers now are planning to test the technology in patients.

"In terms of the major challenges involving size and scale, we've already crossed some key bridges," said co-senior author Wilson Z. Ray, MD, assistant professor of neurological and orthopaedic surgery at Washington University.

In patients with traumatic brain injuries, neurosurgeons attempt to decrease the pressure inside the skull using medications. If pressure cannot be reduced sufficiently, patients often undergo surgery. The new devices could be placed into the brain at multiple locations during such operations.

"The ultimate strategy is to have a device that you can place in the brain -- or in other organs in the body -- that is entirely implanted, intimately connected with the organ you want to monitor and can transmit signals wirelessly to provide information on the health of that organ, allowing doctors to intervene if necessary to prevent bigger problems," Murphy said. "And then after the critical period that you actually want to monitor, it will dissolve away and disappear."

Washington University School of Medicine

A ‘printing press’ for nanoparticles

This new technique could facilitate use of gold nanoparticles in electronic, medical applications

Gold nanoparticles have unusual optical, electronic and chemical properties, which scientists are seeking to put to use in a range of new technologies, from nanoelectronics to cancer treatments.

Some of the most interesting properties of nanoparticles emerge when they are brought close together – either in clusters of just a few particles or in crystals made up of millions of them.  Yet particles that are just millionths of an inch in size are too small to be manipulated by conventional lab tools, so a major challenge has been finding ways to assemble these bits of gold while controlling the three-dimensional shape of their arrangement.

One approach that researchers have developed has been to use tiny structures made from synthetic strands of DNA to help organize nanoparticles. Since DNA strands are programmed to pair with other strands in certain patterns, scientists have attached individual strands of DNA to gold particle surfaces to create a variety of assemblies. But these hybrid gold-DNA nanostructures are intricate and expensive to generate, limiting their potential for use in practical materials. The process is similar, in a sense, to producing books by hand.

Enter the nanoparticle equivalent of the printing press. It’s efficient, re-usable and carries more information than previously possible. In results reported online in Nature Chemistry, researchers from McGill’s Department of Chemistry outline a procedure for making a DNA structure with a specific pattern of strands coming out of it; at the end of each strand is a chemical “sticky patch.”  When a gold nanoparticle is brought into contact to the DNA nanostructure, it sticks to the patches. The scientists then dissolve the assembly in distilled water, separating the DNA nanostructure into its component strands and leaving behind the DNA imprint on the gold nanoparticle. (See illustration.)

“These encoded gold nanoparticles are unprecedented in their information content,” says senior author Hanadi Sleiman, who holds the Canada Research Chair in DNA Nanoscience. “The DNA nanostructures, for their part, can be re-used, much like stamps in an old printing press.”

From stained glass to optoelectronics

Some of the properties of gold nanoparticles have been recognized for centuries.  Medieval artisans added gold chloride to molten glass to create the ruby-red colour in stained-glass windows – the result, as chemists figured out much later, of the light-scattering properties of tiny gold particles. 

Now, the McGill researchers hope their new production technique will help pave the way for use of DNA-encoded nanoparticles in a range of cutting-edge technologies. First author Thomas Edwardson says the next step for the lab will be to investigate the properties of structures made from these new building blocks. “In much the same way that atoms combine to form complex molecules, patterned DNA gold particles can connect to neighbouring particles to form well-defined nanoparticle assemblies.”

These could be put to use in areas including optoelectronic nanodevices and biomedical sciences, the researchers say. The patterns of DNA strands could, for example, be engineered to target specific proteins on cancer cells, and thus serve to detect cancer or to selectively destroy cancer cells. 

Financial support for the research was provided by the Natural Sciences and Engineering Research Council of Canada, the Canada Foundation for Innovation, the Centre for Self-Assembled Chemical Structures, the Canada Research Chairs Program and the Canadian Institutes of Health Research.

“Transfer of molecular recognition information from DNA nanostructures to gold nanoparticles,” Thomas G. W. Edwardson et al, Nature Chemistry, Jan. 4, 2016. DOI: 10.1038/nchem.2420
http://www.nature.com/nchem/journal/vaop/ncurrent/full/nchem.2420.html

McGill University

Scientists discover how cancer cells escape blood vessels

Study offers new targets for drugs that may prevent cancer from spreading.

Scientists at MIT and Massachusetts General Hospital have discovered how cancer cells latch onto blood vessels and invade tissues to form new tumors — a finding that could help them develop drugs that inhibit this process and prevent cancers from metastasizing.

Cancer cells circulating in the bloodstream can stick to blood vessel walls and construct tiny “bridges” through which they inject genetic material that transforms the endothelial cells lining the blood vessels, making them much more hospitable to additional cancer cells, according to the new study.

The researchers also found that they could greatly reduce metastasis in mice by inhibiting the formation of these nanobridges.

“Endothelial cells line every blood vessel and are the first cells in contact with any blood-borne element. They serve as the gateway into and out of tumors and have been the focus of intense research in vascular and cancer biology. These findings bring these two fields together to add greater insight into control of cancer and metastases,” says Elazer Edelman, the Thomas D. and Virginia W. Cabot Professor of Health Sciences and Technology, a member of MIT’s Institute for Medical Engineering and Science and of the Koch Institute for Integrative Cancer Research, and one of the leaders of the research team.

The lead author of the paper, which appears in the Dec. 16 issue of Nature Communications, is Yamicia Connor, a graduate student in the Harvard-MIT Division of Health Sciences and Technology (HST). The paper’s senior author is Shiladitya Sengupta, an assistant professor at HST and at Harvard Medical School.

Building bridges

Metastasis is a multistep process that allows cancer to spread from its original site and form new tumors elsewhere in the body. Certain cancers tend to metastasize to specific locations; for example, lung tumors tend to spread to the brain, and breast tumors to the liver and bone.

To metastasize, tumor cells must first become mobile so they can detach from the initial tumor.

Then they break into nearby blood vessels so they can flow through the body, where they become circulating tumor cells (CTCs). These CTCs must then find a spot where they can latch onto the blood vessel walls and penetrate into adjacent tissue to form a new tumor.

Blood vessels are lined with endothelial cells, which are typically resistant to intruders.

“Normal endothelial cells should not enable a cancer cell to invade, but if a cancer cell can connect with an endothelial cell, and inject signals that enable this endothelial cell to be controlled and completely transformed, then it facilitates metastasis,” Sengupta says.

The researchers first spotted tiny bridges between cancer cells and endothelial cells while using electron microscopy to study the interactions between those cell types. They speculated that the cancer cells might be sending some kind of signal to the endothelial cells.

“Once we saw that these structures allowed for a ubiquitous transfer of a lot of different materials, microRNAs were an obvious interesting molecule because they’re able to very broadly control the genome of a cell in ways that we don’t really understand,” Connor says. “That became our focus.”

MicroRNA, discovered in the early 1990s, helps a cell to fine-tune its gene expression. These strands of RNA, about 22 base pairs long, can interfere with messenger RNA, preventing it from being translated into proteins.

In this case, the researchers found, the injected microRNA makes the endothelial cells “sticky.”

That is, the cells begin to express proteins on their surfaces that attract other cells to adhere to them. This allows additional CTCs to bind to the same site and penetrate through the vessels into the adjacent tissue, forming a new tumor.

“It’s almost like the cancer cells are cooperating with each other to facilitate migration,” Sengupta says. “You just need maybe 1 percent of the endothelial cells to become sticky, and that’s good enough to facilitate metastasis.”

Non-metastatic cancer cells did not produce these invasive nanobridges when grown on endothelial cells.

Erkki Ruoslahti, a professor of cell, molecular, and developmental biology at the University of California at Santa Barbara, says that the discovery is an important advance in understanding tumor metastasis.

“I found it particularly interesting that the transfer of regulatory macromolecules from tumor cells to endothelial cells via intercellular nanotubes appears to be more effective (at least over relatively short distances) than exosome-mediated transfer, which has received a lot of attention lately,” says Ruoslahti, who was not part of the research team.

Shutting down metastasis

The nanobridges are made from the proteins actin and tubulin, which also form the cytoskeleton that gives cells their structure. The researchers found that they could inhibit the formation of these nanobridges, which are about 300 microns long, by giving low doses of drugs that interfere with actin.

When the researchers gave these drugs to mice with tumors that normally metastasize, the tumors did not spread.

Sengupta’s lab is now trying to figure out the mechanism of nanobridge formation in more detail, with an eye toward developing drugs that act more specifically to inhibit the process.

“If we can first understand how these structures are formed, then we can try to design targeted therapies to inhibit their formation, which could be a promising new area for developing drugs that specifically target metastasis,” Connor says.

MIT