Self-assembling drug molecules could fight cancer

A popular method of targeted drug delivery for anti-cancer drugs involves doping another material with the desired pharmaceutical to obtain better targeting efficiency to tumor sites. The problem with this method, researchers have discovered, is that the quantity of drug payload per delivery unit can vary widely and that the materials used for delivery can have toxic side effects.

But what if you could turn the drug molecule itself into a nanoscale delivery system, cutting out the middleman completely?

TEM image of nanotubes formed by self-assembly of an anticancer drug amphiphile. These nanotubes possess a fixed drug loading of 38% (w/w). Image from Cui Lab.

TEM image of nanotubes formed by self-assembly of an anticancer drug amphiphile. These nanotubes possess a fixed drug loading of 38% (w/w). Image from Cui Lab.

Using the process of molecular self-assembly, that is what Honggang Cui, an assistant professor in the Department of Chemical and Biomolecular Engineering at Johns Hopkins University, is attempting to do. His efforts have netted him the prestigious Faculty Early Career Development (CAREER) Award from the National Science Foundation. Cui, an affiliated faculty member of the Johns Hopkins Institute for NanoBioTechnology, will receive the $500,000 award over five years.

Cui explained that a current method of delivering anti-cancer drugs is to enclose them in a nanoscale carrier made of natural or synthetic materials, but this method presents several challenges. “The amount of drug loaded per carrier is very much limited and varies from batch to batch. Even in the same batch, there is a drug loading variation from carrier to carrier. Additionally, the carrier material itself may have toxic side effects,” he said.

Cui’s research seeks to eliminate the need for the carrier by coaxing the drug molecules themselves to form their own carrier through the process of self-assembly. His team is developing new molecular engineering strategies to assemble anti-cancer drugs into supramolecular nanostructures.

“Such supramolecules could carry as much as 100 percent of the drug, would possess a fixed amount of drug per nanostructure and would minimize the potential toxicity of the carrier,” Cui said.

To learn more about research in the Cui lab go to http://www.jhu.edu/cui/

 

Molecular culprit linked to breast cancer spread

Johns Hopkins researchers have uncovered a protein “partner” commonly used by breast cancer cells to unlock genes needed for spreading the disease around the body. A report on the discovery, published Nov. 5 on the website of the Proceedings of the National Academy of Sciences, details how some tumors get the tools they need to metastasize.

“We’ve identified a protein that wasn’t known before to be involved in breast cancer progression,” says Gregg Semenza, M.D., Ph.D., the C. Michael Armstrong Professor of Medicine at the Johns Hopkins University School of Medicine and director of the Vascular Program at the university’s Institute for Cell Engineering. “The protein JMJD2C is the key that opens up a whole suite of genes needed for tumors to grow and metastasize, so it represents a potential target for cancer drug development.” Semenza also is associate director of the Johns Hopkins Physical Sciences-Oncology Center.

Semenza and his colleagues made their finding when they traced the activity of HIF-1, a protein known to switch on hundreds of genes involved in development, red blood cell production, and metabolism in normal cells. Previous studies had shown that HIF-1 could also be hijacked to switch on genes needed to make breast tumors more malignant.

Would-be tumor cells face a host of challenges as they make the transition from working with their host to working against it, such as the need to evade the immune system and to produce more cancer cells, explains Weibo Luo, Ph.D., an instructor in the Institute for Cell Engineering and Department of Biological Chemistry who led the project. All of these efforts require switching on the right genes for the job.

To learn more about how HIF-1 works, the researchers tested a range of human proteins to see whether they would interact with HIF-1. They then sifted through the 200 resulting hits, looking for proteins involved in chemical changes to sections of DNA that determine whether or not the genes they contain are available for use. “In order for HIF-1 to switch genes on, they have to be available, but many of the genes HIF-1 activates are normally locked down in mature cells,” explains Luo. “So we thought HIF-1 must have a partner that can do the unlocking.”

That partner turned out to be JMJD2C, Luo says. Delving deeper, the researchers found that HIF-1 switches on the JMJD2C gene, stimulating production of the protein. HIF-1′s presence also enables JMJD2C to bind to DNA at other HIF-1 target genes, and then loosen those DNA sections, enabling more HIF-1 to bind to the same sites and activate the target genes.

To test the implications of their discovery, the research team injected mice with breast cancer cells in which the JMJD2C protein was not produced. Tumors with depleted JMJD2C were much less likely to grow and metastasize to the lungs, confirming the protein’s role in breast cancer progression, says Luo.

“Active HIF proteins have been found in many types of tumors, so the implications of this finding go beyond breast cancer,” says Luo. “JMJD2C is both an important piece of the puzzle of how tumors metastasize, and a potential target for anti-cancer therapy.”

Other authors of the research report are Ryan Chang, Jun Zhong, Ph.D., and Akhilesh Pandey, M.D., Ph.D., all of the Johns Hopkins University School of Medicine.

This work was supported by grants from the National Heart, Lung, and Blood Institute (contracts N01-HV28180 and HHS-N268201000032C), and by funds from the Johns Hopkins Institute for Cell Engineering.

On the Web:

Johns Hopkins Physical Sciences-Oncology Center: http://psoc.inbt.jhu.edu/

Link to article: http://www.pnas.org/content/early/2012/10/31/1217394109.abstract

Semenza lab: http://www.hopkinsmedicine.org/institute_cell_engineering/experts/gregg_semenza.html

Q&A with Semenza: http://www.hopkinsmedicine.org/institute_cell_engineering/experts/meet_scientists/gregg_semenza.html

Original press release by Shawna WilliamsCatherine Kolf and Vanessa McMains

 

 

Cancer data stored in the cloud could improve treatments

These days, storing photos or music remotely in “the cloud”  has become common place. Now Johns Hopkins researchers are applying the concept to the storage of medical data in the hopes of predicting and improving cancer patient treatments and outcomes.

Images courtesy Denis Wirtz/JHU

“The long-range goal is to make these data available through the Internet to physicians who are diagnosing and treating cancer patients around the world,” said Denis Wirtz , associate director of the Johns Hopkins Institute for NanoBioTechnology and professor of chemical and biomolecular engineering. Using a $3.75 million grant over five years from the National Cancer Institute Common Fund Single Cell Analysis Program, Wirtz launched the program in October, with two colleagues from the Johns Hopkins School of Medicine, Anirban Maitra and Ralph Hruban.

Initially the database will focus on information from pancreatic cancer patient cell lines but will expand to other types of cancer, including ovarian.  Data gathered and stored will be at the single cell level, which Wirtz explains, provides better information for predicting how individual patients may respond to certain drugs. Drugs that work well for one patient may do nothing at all, or even be harmful, for another, Wirtz said. Understanding and predicting these outcomes before treatment is a step toward more personalized medicine, he added.

To read more about “cloud pathology,” go to the press release issued by John Hopkins University.

Johns Hopkins Institute for NanoBioTechnology

Johns Hopkins Engineering in Oncology Center

Johns Hopkins Kimmel Cancer Center

 

Konstantopoulos named BMES fellow

Konstantinos Konstantopoulos (Photo by Mary Spiro)

Konstantinos Konstantopoulos, professor and chair of the Department of Chemical and Biomolecular Engineering at Johns Hopkins University’s Whiting School of Engineering has been named a Fellow of the Biomedical Engineering Society (BMES). Konstantopoulos was one of only nine fellows elected to the Society’s Class of 2012.

BMES states that Konstantopoulos received this honor in recognition of his “seminal bioengineering research contributions involving the discovery and characterization of novel selectin ligands expressed by metastatic tumor cells.”  Formal installation of fellows will take place at the BMES annual meeting  October 24-27 in Atlanta.

Konstantopoulos is an affiliated faculty member of Johns Hopkins Institute for NanoBioTechnology. He is also a project leader with the Johns Hopkins Physical Sciences-Oncology Center. Together with Martin Pomper, a School of Medicine professor of radiology and co-principal investigator of the Johns Hopkins Center of Cancer Nanotechnology Excellence, Konstantopoulos is researching mechanochemical effects on metastasis.

Specifically, his work investigates the effects of fluid mechanical forces at different oxygen tension microenvironments on tumor cell signaling, adhesion and migration. Fluid flow in and around tumor tissue modulates the mechanical microenvironment, including the forces acting on the cell surface and the tethering force on cell-substrate connections. Cells in the interior of a tumor mass experience a lower oxygen tension microenvironment and lower fluid velocities than those at the edges in proximity with a functional blood vessel, and are prompted to produce different biochemical signals. These differential responses affect tumor cell fate that is, whether a cell will live or die, and whether it will be able to detach and migrate to secondary sites in the body.

According to the BMES website, members who demonstrate exceptional achievements and experience in the field of biomedical engineering, as well as a record of membership and participation in the Society, have the opportunity to become fellows. Fellows are selected and conferred  by the BMES board of directors through a highly selective process. Nominations for each of these categories may be made by Society members and the board of directors.

Learn more about research in the Konstantopoulos Lab here.

 

 

Coated nanoparticles move easily into brain tissue

Real-time imaging of nanoparticles green) coated with polyethylene-glycol (PEG), a hydrophilic, non-toxic polymer, penetrate within normal rodent brain. Without the PEG coating, negatively charged, hydrophobic particles (red) of a similar size do not penetrate. Image by Elizabeth Nance, Kurt Sailor, Graeme Woodworth.

Johns Hopkins researchers report they are one step closer to having a drug-delivery system flexible enough to overcome some key challenges posed by brain cancer and perhaps other maladies affecting that organ. In a report published online Aug. 29 in Science Translational Medicine, the Johns Hopkins team says its bioengineers have designed nanoparticles that can safely and predictably infiltrate deep into the brain when tested in rodent and human tissue.

“We are pleased to have found a way to prevent drug-embedded particles from sticking to their surroundings so that they can spread once they are in the brain,” said Justin Hanes, Lewis J. Ort Professor of Ophthalmology and project leader in the Johns Hopkins Center of Cancer Nanotechnology Excellence.

Standard protocols following the removal of brain tumors include chemotherapy directly applied to the surgical site to kill any cancer cells left behind. This method, however, is only partially effective because it is hard to administer a dose of chemotherapy high enough to sufficiently penetrate the tissue to be effective and low enough to be safe for the patient and healthy tissue. Furthermore, previous versions of drug-loaded nanoparticles typically adhere to the surgical site and do not penetrate into the tissue.

These newly engineered nanoparticles overcome this challenge. Elizabeth Nance, a graduate student in chemical and biomolecular engineering, and Johns Hopkins neurosurgeon Graeme Woodworth, suspected that drug penetration might be improved if drug-delivery nanoparticles interacted minimally with their surroundings. Nance achieved this by coating nano-scale beads with a dense layer of PEG or poly(ethylene glycol). The team then injected the coated beads, which had been marked with a fluorescent tag,  into slices of rodent and human brain tissue. They found that a dense coating of PEG allowed larger beads to penetrate the tissue, even those beads that were nearly twice the size previously thought to be the maximum possible for penetration within the brain. They then tested these beads in live rodent brains and found the same results.

Elizabeth Nance. Photo by Ming Yang.

The results were similar when biodegradable nanoparticles carrying the chemotherapy drug paclitaxel and coated with PEG were used. “It’s really exciting that we now have particles that can carry five times more drug, release it for three times as long and penetrate farther into the brain than before,” said Nance. “The next step is to see if we can slow tumor growth or recurrence in rodents.”

Woodworth added that the team “also wants to optimize the particles and pair them with drugs to treat other brain diseases, like multiple sclerosis, stroke, traumatic brain injury, Alzheimer’s and Parkinson’s.” Another goal for the team is to be able to administer their nanoparticles intravenously, which is research they have already begun.

Additional authors on the paper include Kurt Sailor, Ting-Yu Shih, Qingguo Xu, Ganesh Swaminathan, Dennis Xiang, and Charles Eberhart, all from The Johns Hopkins University.

Story adapted from an original press release by Cathy Kolf.

 

Additional news coverage of this research can be found at the following links:

Nanotechnology/Bio & Medicine

Death and Taxes Mag

New Scientist Health

Nanotech Web

Portugese news release (in Portugese)

German Public Radio (in German)

Light-activated synthetic protein illuminates disease destruction

Illustration of collagen’s rope-like structure. Click to watch video. (INBT Animation Studios)

Johns Hopkins researchers have created a synthetic protein that, when activated by ultraviolet light, can guide doctors to places within the body where cancer, arthritis and other serious medical disorders can be detected. The synthetic protein does not zero in directly on the diseased cells. Instead, it binds to nearby collagen that has been degraded by disease or injury.

“These disease cells are like burglars who break into a house and do lots of damage but who are not there when the police arrive,” said S. Michael Yu, a faculty member in the Whiting School of Engineering’s Department of Materials Science and Engineering. “Instead of looking for the burglars, our synthetic protein is reacting to evidence left at the scene of the crime,” said Yu, who was principal investigator in the study.

The technique could lead to a new type of diagnostic imaging technology and may someday serve as a way to move medications to parts of the body where signs of disease have been found. In a study published in the Aug. 27-31 Online Early Edition of Proceedings of the National Academy of Sciences, the researchers reported success in using the synthetic protein in mouse models to locate prostate and pancreatic cancers, as well as to detect abnormal bone growth activity associated with Marfan syndrome.

Collagen, the body’s most abundant protein, provides structure and creates a sturdy framework upon which cells build nerves, bone and skin. Some buildup and degradation of collagen is normal, but disease cells such as cancer can send out enzymes that break down collagen at an accelerated pace. It is this excessive damage, caused by disease, that the new synthetic protein can detect, the researchers said.

A key collaborator was Martin Pomper, a School of Medicine professor of radiology and co-principal investigator of the Johns Hopkins Center of Cancer Nanotechnology Excellence. Pomper and Yu met as fellow affiliates of the Johns Hopkins Institute for NanoBioTechnology. “A major unmet medical need is for a better non-invasive characterization of disrupted collagen, which occurs in a wide variety of disorders,” Pomper said. “Michael has found what could be a very elegant and practical solution, which we are converting into a suite of imaging and potential agents for diagnosis and treatment.”

The synthetic proteins used in the study are called collagen mimetic peptides or CMPs. These tiny bits of protein are attracted to and physically bind to degraded strands of collagen, particularly those damaged by disease. Fluorescent tags are placed on each CMP so that it will show up when doctors scan tissue with fluorescent imaging equipment. The glowing areas indicate the location of damaged collagen that is likely to be associated with disease.

In developing the technique, the researchers faced a challenge because CMPs tend to bind with one another and form their own structures, similar to DNA, in a way that would cause them to ignore the disease-linked collagen targeted by the researchers.

To remedy this, the study’s lead author, Yang Li, synthesized CMPs that possess a chemical “cage” to keep the proteins from binding with one another. Just prior to entering the bloodstream to search for damaged collagen, a powerful ultraviolet light is used to “unlock” the cage and allow the CMPs to initiate their disease-tracking mission. Li is a doctoral student from the Department of Chemistry in the Krieger School of Arts and Sciences at Johns Hopkins. Yu, who holds a joint appointment in that department, is his doctoral adviser.

Yu’s team tested Li’s fluorescently tagged and caged peptides by injecting them into lab mice that possessed both prostate and pancreatic human cancer cells. Through a series of fluorescent images taken over four days, researchers tracked single strands of the synthetic protein spreading throughout the tumor sites via blood vessels and binding to collagen that had been damaged by cancer.

Similar in vivo tests showed that the CMP can target bones and cartilage that contain large amounts of degraded collagen. Therefore, the new protein could be used for diagnosis and treatment related to bone and cartilage damage.

Although the process is not well understood, the breakdown and rebuilding of collagen is thought to play a role in the excessive bone growth found in patients with Marfan syndrome. Yu’s team tested their CMPs on a mouse model for this disease and saw increased CMP binding in the ribs and spines of the Marfan mice, as compared to the control mice.

Funding for the research was provided by the National Science Foundation, the National Institutes of Health and the Department of Defense. The synthetic protein process used in this research is protected by patents obtained through the Johns Hopkins Technology Transfer Office.

Along with Yu, Li and Pomper, co-authors of this study were instructor Catherine A. Foss and medical resident Collin M. Torok from the Department of Radiology and Radiological Science at the Johns Hopkins School of Medicine; Harry C. Dietz, a professor, and Jefferson J. Doyle, a doctoral student, both of the Howard Hughes Medical Institute and Institute of Genetic Medicine at the School of Medicine; and Daniel D. Summerfield a former master’s student in the Department of Materials Science and Engineering.

Adapted from an original press release by Phil Sneiderman.

 

Killing prostate cancer cells with out harming the healthy cells

Experimenting with human prostate cancer cells and mice, cancer imaging experts at Johns Hopkins say they have developed a method for finding and killing malignant cells while sparing healthy ones.

The method, called “theranostic” imaging, targets and tracks potent drug therapies directly and only to cancer cells. It relies on binding an originally inactive form of drug chemotherapy, with an enzyme, to specific proteins on tumor cell surfaces and detecting the drug’s absorption into the tumor. The binding of the highly specific drug-protein complex, or nanoplex, to the cell surface allows it to get inside the cancerous cell, where the enzyme slowly activates the tumor-killing drug.

Researchers say their findings, published in the journal American Chemical Society Nano online Aug. 6, are believed to be the first to show that chemotherapies can be precisely controlled at the molecular level to maximize their effectiveness against tumors, while also minimizing their side effects.

Senior study investigator Zaver Bhujwalla, Ph.D., a professor at the Johns Hopkins University School of Medicine and its Kimmel Cancer Center, notes that a persistent problem with current chemotherapy is that it attacks all kinds of cells and tissues, not just cancerous ones.

In the theranostic imaging experiments, overseen by Bhujwalla and study co-investigator Martin Pomper, M.D., Ph.D., investigators directed drugs only to cancer cells, specifically those with prostate-specific membrane antigen, or PSMA cell surface proteins. Both Pomper and Bhujwalla are affiliated faculty members of Johns Hopkins Institute for NanoBioTechnology.

“Our results show a non-invasive imaging approach to following and delivering targeted therapy to any cancer that expresses PSMA,” says Bhujwalla, who also serves as director of the Johns Hopkins In Vivo Cellular and Molecular Imaging Center (ICMIC), where the theranostic imaging studies were developed.

Bhujwalla says the new technique potentially will work against any cancer in which tumors elevate production of certain cell surface proteins. Examples would include breast cancers with HER-2/neu and CXCR4 proteins, and some liver, lung and kidney cancers also known to express particular proteins. She notes that PSMA is expressed in the vessels of most solid tumors, suggesting that the nanoplex reported in the latest study could be used in general to image and treat a variety of cancers.

In their latest series of experiments, primarily in mice injected with human prostate tumor cells, Bhujwalla and the Johns Hopkins team tested their ability to track with imaging devices the delivery of anti-cancer drugs directly to tumors. Some of the tumors comprised cells with PSMA, while other so-called control tumors had none. Included in the drug nanoplex were small strands of RNA, cell construction acids that can be used instead to block and turn down production of a well-known enzyme, choline kinase, whose levels usually rise with tumor growth. All nanoplex components were imaged inside the tumor, in addition to dropping choline kinase production, which decreased by 80 percent within 48 hours of nanoplex absorption into cells with ample PSMA. When researchers used antibodies to block the action of PSMA, down went the level of nanoplex uptake and drug activation in cancerous cells as measured by dimming of the image.

Different concentrations of the drug nanoplex, tagged with radioactive and fluorescent molecules, were mixed in the lab with prostate cancer tissue cells, some of which had extra PSMA and others which had none. Only those cells with extra PSMA showed nanoplex uptake, as measured by image intensity, which later decreased when PSMA-blocking chemicals were added (back to levels seen in cells with almost no PSMA).

Additional experiments involving injections of three different concentrations of the drug nanoplex showed no damage to other vital mouse organs, such as the kidney and liver, nor any uptick in the mouse immune system response.

“Our theranostic imaging approach shows how the best methods of detection and treatment can be combined to form highly specialized, more potent and safer forms of chemotherapy,” says Pomper, a professor at Johns Hopkins who also serves as an associate director at ICMIC.

He says that an important goal for theranostic imaging is to move it beyond standard chemotherapy that attacks one target molecule at a time.

“With theranostic imaging, we can attack multiple tumor targets, making it harder for the tumor to evade drug treatment,” says Pomper, who is already working with colleagues at Johns Hopkins to identify other molecular targets.

The most recent studies were performed at Johns Hopkins over two years, starting in 2010, with funding support from the National Cancer Institute, part of the National Institutes of Health. The corresponding grant numbers are P50-CA103175, RO1-CA138515 and RO1-CA134675.

In addition to Bhujwalla and Pomper, other Johns Hopkins researchers from the Russell H. Morgan Department of Radiology involved in this imaging study were lead investigators Zhihang Chen, Ph.D., and Mary-France Penet, Ph.D. Additional study co-investigators were Sridhar Nimmagadda, Ph.D.; Li Cong, Ph.D.; Sangeeta Banerjee, Ph.D.; Paul Winnard Jr., Ph.D.; Dmitri Artemov, Ph.D.; and Kristine Glunde, Ph.D.

Press release by David March

Therapeutic nanolex containing multi-modal imaging reporters targeted to prostate specific membrane antigen (PSMA), which is expressed on the cell surface of castrate resistant PCa. (Image by Chen et al. from ACS Nano 2012).

 

Tumor cells change when put into a ‘tight spot’

Konstantinos Konstantopoulos addresses audience at 2012 NanoBio Symposium. Photo by Mary Spiro/JHU

“Cell migration represents a key aspect of cancer metastasis,” said Konstantinos Konstantopoulos, professor and chair of the Department of Chemical and Biomolecular Engineering at Johns Hopkins University. Konstantopoulos was among the invited faculty speakers for the 2012 NanoBio Symposium.

Cancer metastasis, the migration of cancer cells from a primary tumor to other parts of the body, represents an important topic among professors affiliated with Johns Hopkins Institute for NanoBioTechnology. Surprisingly, 90 percent of cancer deaths are caused from this spread, not from the primary tumor alone. Konstantopoulos and his lab group are working to understand the metastatic process better so that effective preventions and treatments can be established. His students have studied metastatic breast cancer cells in the lab by tracking their migration patterns. The group has fabricated a microfluidic-based cell migration chamber that contains channels of varying widths. Cells are seeded at one opening of the channels, and fetal bovine serum is used as a chemoattractant at the other opening of the channels to induce the cells to move across. These channels can be as big as 50 µm wide, where cells can spread out to the fullest extent, or as small as 3 µm wide, where cells have to narrowly squeeze themselves to fit through.

A current dogma in the field of cell migration is that actin polymerization and actomyosin contractility give cells the flexibility they need to protrude and contract across a matrix in order to migrate. When Konstantopoulos’s students observed cells in the wide, 50 µm-wide channels, they saw actin distributed over the entirety of the cells, as expected. They also observed that when the cells were treated with drugs that inhibited actin polymerization and actomyosin contractility, they did not migrate across the channels, also as expected.

However, when the students observed cells in the narrow, 3 µm-wide channels, they were surprised to see actin only at the leading and trailing edges of the cells. Additionally, the inhibition of actin polymerization and actomyosin contractility did not affect the cells’ ability to migrate.

“Actin polymerization and actomyosin contractility are critical for 2D cell migration but dispensable for migration through narrow channels,” concluded Konstantopoulos. The data challenged what many had previously believed about cell migration by showing that cells in confined spaces did not need these actin components to migrate.

These findings are indeed important in the context of cancer metastasis, where cells must migrate through a heterogeneous environment of both wide and narrow areas. Konstantopoulos’s data gives a better mechanistic understanding of the different methods cancer cells use to migrate in diverse surroundings.

Future studies in the Konstantopoulos lab will focus on how tumor cells decide which migratory paths to take. INBT-sponsored graduate student Colin Paul has developed an additional microfluidic device that contains channels with bifurcations. He hopes to determine what factors guide a cell in one direction versus another. The Konstantopoulos lab hopes to continue to understand exactly how tumor cells migrate so that new therapies can eventually be developed to stop metastasis.

Story by Allison Chambliss, a Ph.D. student in the Department of Chemical and Biomolecular Engineering with interests in cellular biophysics and epigenetics.

Watch a video related to this research here.

Konstantopoulos reported these findings in October 2012 The Journal of the Federation of American Societies for Experimental Biology.  Read the article online here.

 

Nanoparticles slip through mucus barrier to protect against herpes virus

“Thick, sticky mucus layers limit effectiveness of drug delivery to mucosal tissues. Mucus-penetrating particles or MPPs (in red) are able to penetrate mucus, covering the entire surface of the mouse vagina (in blue). Improved distribution and retention of MPPs led to significantly increased protection in a mouse model for herpes simplex virus infection. Image by Laura Ensign.

Johns Hopkins researchers say they have demonstrated for the first time, in animals, that nanoparticles can slip through mucus to deliver drugs directly to tissue surfaces in need of protection.

The researchers used these mucus-penetrating particles, or MPPs, to protect against vaginal herpes infections in mice. The goal is to create similar MPPs to deliver drugs that protect humans against sexually transmitted diseases or even treat cancer.

“This is the first in vivo proof that MPPs can improve distribution, retention, and protection by a drug applied to a mucosal surface, said Justin Hanes, Ph.D., a professor of ophthalmology at the Johns Hopkins Wilmer Eye Institute and director of the Center for Nanomedicine at the Johns Hopkins University School of Medicine.

Hanes also is a principal investigator with the Johns Hopkins Center of Cancer Nanotechnology Excellence. Results of his team’s experiments are described in the June 13 issue of the journal Science Translational Medicine.

The moist mucosal surfaces of the body, like the eyes, lungs, intestines and genital tract, are protected from pathogens and toxins by layers of moist sticky mucus that is constantly secreted and shed, forming our outermost protective barrier.

“Although many people associate mucus with disgusting cold and cough symptoms, mucus is in fact a sticky barrier that helps keep you healthy,” says Laura Ensign, a doctoral student affiliated with the Center for Nanomedicine at the School of Medicine and with the Department of Chemical and Biomolecular Engineering at Johns Hopkins’ Whiting School of Engineering. She is the lead author of the journal report.

Unfortunately, Ensign noted, mucus barriers also stop helpful drug delivery, especially conventional nanoparticles intended for sustained drug delivery. In a Johns Hopkins laboratory, researchers developed nanoparticles that do not stick to mucus so they can slip through to reach the cells on the mucosal surface, in this case the surface of the mouse vagina, she added.

Ensign explained that conventional nanoparticles actually stick to mucus before releasing their drug payload and are then removed when the mucus is replenished, often within minutes to hours. Working with researchers in the laboratory of Richard Cone, Ph.D., in the Department of Biophysics in the university’s Krieger School of Arts and Sciences, the Hanes team fabricated particles with surface chemistry that mimics a key feature of viruses that readily infect mucosal surfaces.

“Richard Cone’s lab found that viruses, such as the human papilloma virus, could diffuse through human cervical mucus as fast as they diffuse through water. These ‘slippery viruses’ have surfaces that are ‘water-loving,’ ” Hanes said. “In contrast, many nanoparticles intended to deliver drugs to mucosal surfaces are ‘mucoadhesive’ and ‘oil-loving,’ but these nanoparticles stick to the superficial layers of the mucus barrier, the layers that are most rapidly removed.”

To make their mucus-penetrating particles, the team transformed conventional ‘oil-loving’ nanoparticles by coating them with a substance used in many commercial pharmaceutical products: polyethylene glycol. PEG makes the particles “water-loving,” like the viruses that slip right through mucus.

“The key is that the nanoparticles, like viruses, have to be small enough to go through the openings in the mucus mesh, and also have surfaces that mucus can’t stick to. If you think about it,” said Ensign, “mucus sticks to almost everything.”

“Viruses have evolved over millions of years to become slippery pathogens that readily penetrate our protective mucus barriers,” said Cone, “and engineering nanoparticles that penetrate the mucus barrier just like viruses is proving to be a clever way to deliver drugs.”

Hanes emphasized that the MPPs provided greatly improved protective efficacy while at the same time reducing the effective dose of drug needed 10-fold. Furthermore, Hanes added, the MPPs “continue to supply drug for at least a day and provide nearly 100 percent coverage of the mucosal surface of the vagina and ectocervix” in their laboratory mice.

“We’ve shown that mucus-penetrating particles are safe for vaginal administration in mice. Our next move will be to show that they are safe for vaginal administration in humans,” Ensign said. “Now our laboratory currently is working on an MPP formulation of a drug that protects against HIV infection that we hope will be tested in humans.”

Their technology could lead to a once-daily treatment for preventing sexually transmitted diseases, for contraception and for treatment of cervico-vaginal disorders, Ensign said.

Ensign added that MPP technology has the potential to prevent a wide range of mucosal diseases and infections, including chronic obstructive pulmonary disease, lung cancer, and cystic fibrosis,” Ensign said.

Additional authors on the paper include postdoctoral fellow Ying-Ying Wang and research specialist Timothy Hoen from the Department of Biophysics; former master’s student Terence Tse from the Department of Chemical and Biomolecular Engineering; and Benjamin Tang, formerly of Johns Hopkins School of Medicine and currently at the Massachusetts Institute of Technology.

Under a licensing agreement between Kala Pharmaceuticals and the Johns Hopkins University, Hanes is entitled to a share of royalties received by the university on sales of products used in the study.

Hanes and the university own Kala Pharmaceuticals stock, which is subject to certain restrictions under university policy. Hanes is also a founder, a director and a paid consultant to Kala Pharmaceuticals. The terms of this arrangement are being managed by The Johns Hopkins University in accordance with its conflict of interest policies.”

Story by Mary Spiro

Additional news coverage of this research may be found at the following links:

Phys.org

WYPR: The Mucus Ruse

Scientific American

 

Meet INBT’s summer interns, already digging into their research

Research does not take a holiday during the summer at Johns Hopkins University in Baltimore, Md. In fact, it ramps up with the addition of many new faces from across the country.

The Johns Hopkins Institute for NanoBioTechnology summer research interns have arrived and are already busy at work in various laboratories. This year’s group is the largest the institute has ever hosted, with 17 undergraduates from universities nationwide.

Of the total, three students are affiliated with the Center of Cancer Nanotechnology Excellence and four are affiliated with the Physical Sciences-Oncology Center. The remaining 10 are part of the National Science Foundation Research Experience for Undergraduates program. All are hosted through INBT, which serves as a hub for their academic and social activities.

INBT summer interns conduct 10 weeks of research in a laboratory either on the Homewood or the medical campus of the University. At the end of that time, students have learned how to work in a multidisciplinary team and how to manage a short term research project.  They also discover if research is a pathway they want to pursue after earning their bachelor’s degrees.

In August, interns from many of the science, medicine, engineering and public health summer programs will gather for a  poster session to be held on August 2 at 3 p.m. in Turner Concourse. The poster session will allow students to show off the results of their their work.

This year’s INBT/PS-OC/CCNE interns include:

At the Whiting School of Engineering…

Amani Alkayyali from Wayne State University is an REU student in the laboratory of Honggang Cui assistant professor in the Department of Chemical and Biomolecular Engineering. Also in the Cui lab are CCNE intern Matthew Fong from the University of California, Berkeley and Michelle LaComb, an REU student from Rice University.

Sharon Gerecht, assistant professor in the Department of Chemical and Biomolecular engineering, is hosting three interns. Josh Porterfield of Cornell University and Carolyn Zhang from the University of California, San Diego are both PS-OC interns, and Bria Macklin of Howard University is an REU intern.

Jacqueline Carozza of Cornell University is a PS-OC student working in the lab of Denis Wirtz, professor in the Department Chemical and Biomolecular Engineering. Cassandra Loren from Oregon State University is a PS-OC intern also working in the Wirtz lab.

Eric Do from the University of Washington is an REU working in the lab of assistant professor Margarita Herrara-Alonso in the Department of Materials Science and Engineering.

Olivia Hentz from Cornell is an REU student working in the lab of Jonah Erlebacher, professor in the Department of Materials Science and Engineering.

Justin Samorajski from the University of Dallas is a returning summer intern, once again working in the materials science and engineering lab of professor Peter Searson as part of the CCNE.

At the School of Medicine…

Lauren Lee of Cornell University is an REU working in the lab of biomedical engineering lab of associate professor Hai-Quan Mao.

Albert Lu from the University of California Berkeley is a CCNE intern working in the biomedical engineering lab of associate professor Jeff Wang.

Bianca Lascano from Norfolk State University is an REU in assistant professor Jordan Green’s biomedical engineering lab.

Charlie Nusbaum of the Richard Stockton College is an REU intern in the radiation oncology lab of assistant professor Robert Ivkov.

At the Krieger School of Arts and Sciences…

Anthony Loder of Rowan University is an REU working in the biology lab of assistant professor Xin Chen.

Daniel McClelland is also REU from Bethany College works in the chemistry laboratory of professor Howard Fairbrother.