Three-way brain tumor therapy sparks immune system with radiation

Johns Hopkins researchers have found that combining radiation with two therapies that activate the immune system allow mice with brain tumors (glioblastoma) to survive longer than mice who did not receive the combo treatment. INBT affiliated faculty member Michael Lim, M.D., an associate professor of neurosurgery, oncology at the Johns Hopkins University School of Medicine, said the radiation may act “as kind of kindling, to try to induce an immune response.”

brainRead the full press release from Johns Hopkins regarding the publication in PLoS One journal below:

A triple therapy for glioblastoma, including two types of immunotherapy and targeted radiation, has significantly prolonged the survival of mice with these brain cancers, according to a new report by scientists at the Johns Hopkins Kimmel Cancer Center.

Mice with implanted, mouse-derived glioblastoma cells lived an average of 67 days after the triple therapy, compared with mice that lasted 24 days when they received only the two immunotherapies. Half of the mice who received the triple therapy lived 100 days or more and were protected against further tumors when new cancer cells were re-injected under the animals’ skins.

The combination treatment described in the July 11 issue of PLOS One consists of highly focused radiation therapy targeted specifically to the tumor and strategies that lift the brakes and activate the body’s immune system, allowing anti-cancer drugs to attack the tumor. One of the immunotherapies is an antibody that binds to and blocks an immune checkpoint molecule on T cells called CTLA-4, allowing the T-cells to infiltrate and fight tumor cells. The second immunotherapy, known as 4-1BB, supplies a positive “go” signal, stimulating anti-tumor T cells.

None of the treatments are new, but were used by the Johns Hopkins team to demonstrate the value of combining treatments that augment the immune response against glioblastomas, the most common brain tumors in human adults. The prognosis is generally poor, even with early treatment.

“We’re trying to find that optimal balance between pushing and pulling the immune system to kill cancer,” said Charles Drake, M.D., Ph.D., an associate professor of oncology, immunology and urology, and medical oncologist at the Johns Hopkins Kimmel Cancer Center.

The researchers speculate that when radiation destroys tumor cells, the dead tumor cells may release proteins that help train immune cells to recognize and attack the cancer, said Michael Lim, M.D., an associate professor of neurosurgery, oncology at the Johns Hopkins University School of Medicine and member of Johns Hopkins’ Institute of NanoBiotechnology.

“Traditionally, radiation is used as a definitive therapy to directly kill cancer cells,” said Lim, who also serves as director of the Brain Tumor Immunotherapy Program and director of the Metastatic Brain Tumor Center at Johns Hopkins Medicine. “But in this situation we’re using radiation as kind of kindling, to try to induce an immune response.”

Lim says if further studies affirm the value of the triple therapy in animals and humans, the radiation could be delivered a few days before or after the immunotherapies and still achieve the same results. Lim said this leeway “could make applications of this therapy in patients possible.”

The researchers say they were also encouraged to see that the triple therapy created “immune memory” in mice that were long-term survivors. When brain tumor cells were re-introduced under the skin of the animals, their immune systems appeared to protect them against the development of a new brain tumor.

Drake said since the immune system usually doesn’t generate a memory when foreign (tumor) cells are still present in the body. “But the idea that this combination treatment was successful at generating immunological memory really suggests that we could do this in patients and generate some long-term responses.”

The researchers are developing a variety of clinical trials to test combination therapies against brain tumors.

Other researchers on the study include Zineb Belcaid, Jillian A. Phallen, Alfred P. See, Dimitrios Mathios, Chelsea Gottschalk, Sarah Nicholas, Meghan Kellett, Jacob Ruzevick, Christopher Jackson, Xiaobu Ye, Betty Tyler, and Henry Brem of the Department of Neurosurgery at Johns Hopkins University School of Medicine; Jing Zeng, Phuoc T. Tran, and John W. Wong of the Department of Radiation Oncology and Molecular Radiation Sciences at the Johns Hopkins Kimmel Cancer Center;  and Emilia Albesiano, Nicholas M. Durham, and Drew M. Pardoll at the Kimmel Center’s Department of Oncology and Medicine, Division of Immunology.

Funding for the study was provided by the WW Smith Charitable Foundation and individual patient donations.

Michael Lim is a consultant for Accuray and receives research funding from Accuray, Bristol-Meyers Squibb, Celldex and Aegenus. Charles Drake has served as a consultant for Amplimmune, Bristol-Meyers Squibb, Compugen, Dendreon, ImmunExcite and Roche/Genentech and is on the Scientific Advisory Board of Compugen. He receives research funding from Bristol-Meyers Squibb, Aduro and Janssen and has stock ownership in Compugen. Drew Pardoll is a consultant/advisor for Jounce Therapeutics, Bristol-Meyers Squibb, ImmuneXcite and Aduro and receives research funding from Bristol-Meyers Squibb. Jing Zeng, Michael Lim, Charles Drake and Drew Pardoll hold a patent for the work related to this study.

The authors declare that they have a patent relating to material pertinent to this article; this international patent application (PCT/US2012/043124) is entitled “Use of Adjuvant Focused Radiation Including Stereotactic Radiosurgery for Augmenting Immune Based Therapies Against Neoplasms.” These relationships are being managed by The Johns Hopkins University in accordance with its conflict of interest policies.

For all press inquiries regarding INBT, its faculty and programs, contact Mary Spiro, mspiro@jhu.edu or 410-516-4802.

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)