Τετάρτη, 25 Νοεμβρίου 2015

NEW METHOD TO DELIVER DRUG IN TUMOURS

A new, injectable “biogel” is effective in delivering anticancer agents directly into cancerous tumors and killing them, according to a study published by Monette et al in Biomaterials. The technology was developed by researchers at the University of Montreal Hospital Research Centre(CRCHUM) and has been successfully tested in the laboratory.
Gel Details and Advantages
The biogel is liquid at room temperature, and gels at 37 degrees Celsius, human body temperature. “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. 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,” said Réjean Lapointe, PhD, coauthor of the study.
One form of immunotherapy involves treating cancer patients with T lymphocytes or T cells, which are produced naturally by the body and have the ability to destroy cancer cells. However, they are generally too weak and too few to eradicate the cancer alone. T cells are therefore cultivated in the laboratory—often 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, a hormone added to maximize the therapy, have 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 Dr. Lapointe, who is a researcher at the CRCHUM and Professor at the University of Montreal.
The recipe for this biogel was developed by Sophie Lerouge, PhD, a researcher at the CRCHUM and Professor in the Department of Mechanical Engineering at the École de technologie supérieure. The compound is made from chitosane, a biodegradable material extracted from the shells of crustaceans, to which gelling agents are added. “The formulation is liquid at room temperature, which facilitates its injection, but quickly takes on a cohesive and resistant structure at 37 degrees. We also needed a hydrogel that was nontoxic for the body and provided excellent survival and growth of the encapsulated cells,” said a CRCHUM engineer. These specifications were a real challenge for Dr. 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 Dr. Lapointe. The next step is to demonstrate the effectiveness of the biogel in animals and humans. 

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