An injectable biogel effectively delivers anticancer agents directly into cancerous tumors. This technology has already been successfully tested in the laboratory and was described in Biomaterials (doi:10.1016/j.biomaterials.2015.10.021). If successful in human patients, the modality has the potential to revolutionize cancer treatment.
The biogel is a liquid at room temperature that transforms into a gel at human body temperature (37° C).
“The strength of this biogel is that it is compatible with anticancer immune cells. It is used to encapsulate these cells and eventually administer them using a syringe or catheter into the tumor or directly beside it,” said coauthor Réjean Lapointe, PhD, of the University of Montreal Hospital Research Centre (CRCHUM) in Canada.
“Instead of injecting these cells or anticancer drugs throughout the entire body via the bloodstream, we can treat the cancer locally. We hope that this targeted approach will improve current immunotherapies.”
Adoptive cell therapy, a form of immunotherapy, involves treating cancer patients with anticancer immune cells. These cells (T lymphocytes or T cells) are produced naturally by the body and have the ability to destroy cancer cells, but they are generally too weak and too few to eradicate the cancer alone. T cells are therefore cultivated in the laboratory, often by using the patient’s own cells, and then reinjected into the patient’s blood.
While this form of immunotherapy has shown promising results in cases of advanced cancer, it is not always possible to generate enough T cells. Moreover, high doses of interleukin-2 are added to maximize the therapy, but the hormone has a toxic effect.
“With our technique, we only need to administer a few dozen million T cells, instead of the billions currently required. We can also administer compounds that awaken the immune system to fight against cancer,” explained Lapointe.
Sophie Lerouge, PhD, a researcher at the CRCHUM and professor in the Department of Mechanical Engineering at the École de technologie supérieure, developed the biogel.
“The compound is made from chitosan, a biodegradable material extracted from the shells of crustaceans, to which gelling agents are added,” said Lerouge.
“The formulation is liquid at room temperature, which facilitates its injection, but quickly takes on a cohesive and resistant structure at 37°. We also needed a hydrogel that was nontoxic for the body and provided excellent survival and growth of the encapsulated cells,” said Lerouge. These requirements were a real challenge for Lerouge’s team, who tested several formulations before arriving at this intelligent biogel.
The biogel was successfully tested in several in vitro models, including melanoma and kidney cancer.
“The T lymphocytes in the gel are functional and can grow for 2 to 3 weeks, be released from the gel, and kill the cancerous cells,” explained Lapointe. The next step is to demonstrate the effectiveness of the biogel in animals and humans. If the trials are successful, this new approach could be added to current cancer therapies in a few years.