Newswise – A drug carrier capable of reaching the brain, attaching to an aggressive type of tumor called glioblastoma multiforme and releasing a chemotherapy drug has been tested for the first time by Brazilian researchers. According to an article published in the International Journal of Pharmaceutics, the potential treatment has been shown to be effective in isolated cells and animal models through a combination of nanotechnology, chemotherapy and a monoclonal antibody.
Glioblastoma multiforme accounts for 60% of all brain tumors in adults and is also the most aggressive type of brain cancer. Even after surgery, radiotherapy and conventional chemotherapy, patient survival averages about 14 months. One of the reasons is angiogenesis, a process by which the tumor rapidly creates its own blood vessels in order to grow.
“Another difficulty is the blood-brain barrier, which prevents drugs from reaching the tumor,” said Leonardo Di Filippo, doctoral student and researcher at the School of Pharmaceutical Sciences at São Paulo State University in Araraquara. (FCFAr-UNESP).
To address these challenges, Di Filippo worked with fellow researchers from UNESP and two other Brazilian institutions, the University of Campinas (UNICAMP) and the University of São Paulo (USP) in Ribeirão Preto, to combine docetaxel , a potent chemotherapeutic agent, with a nanostructured lipid carrier designed to cross the blood-brain barrier. “We developed a formulation in which the substances were stably combined,” he said.
The researchers also paired the transporter with bevacizumab, a monoclonal antibody developed against vascular endothelial growth factor (VEGF) and approved for other uses. “VEGF is the cancer protein that stimulates angiogenesis and tends to be overexpressed in glioblastoma multiforme,” Di Filippo explained. The goal was to create a formulation capable of entering the brain and releasing a chemotherapy drug to destroy the tumor.
“Developing this system with this app is an innovation,” said Marlus Chorili, a UNESP professor and principal investigator of the FAPESP-supported project.
Quality testing
After creating the nanostructured lipid carrier with docetaxel and bevacizumab, the researchers set out to ensure that it met certain basic criteria. Laboratory tests showed its size to be 128 nanometers, small enough to cross the blood-brain barrier. In addition, the entrapment of docetaxel was 90% and the coupling efficiency of bevacizumab was 62%. “These are positive numbers, sufficient to ensure adequate therapeutic concentrations,” Di Filippo said.
The next step was to evaluate the effects of the compound on two glioblastoma cell lines and healthy cells. The nanocarrier eliminated five times more cancer cells than docetaxel alone without affecting healthy cells. It was particularly effective against U87MG, a glioblastoma cell that overexpresses VEGF, but less so against A172, which expresses relatively little VEGF. “These results show that our nanocarrier selectively attacks cells that express a lot of VEGF,” Di Filippo said.
The researchers also found that the potential drug was able to enter cancer cells and release docetaxel continuously for around 84 hours, suggesting prolonged availability of the chemotherapy drug in the body.
Good results in animals
Using techniques developed by the UNICAMP team, rats were inoculated with glioma cells (glioma is a type of cancer similar to glioblastoma). Five days later, they were divided into six groups: treatment with placebo; docetaxel alone; nanocarrier alone, without bevacizumab or docetaxel; nanocarrier and bevacizumab, without docetaxel; nanocarrier and docetaxel, without bevacizumab; nanocarrier with docetaxel and bevacizumab.
After 15 days, the first four groups turned out not to have benefited from the treatment. In the fifth group (nanocarrier with docetaxel) and the sixth group (nanocarrier with docetaxel and bevacizumab), the tumor volume was reduced by 40% and 70% respectively. “These are significant numbers for trials like this,” Chorilli said.
The researchers also found that the formulation did not cause any deterioration in levels of biomarkers such as albumin and creatinine compared to using docetaxel alone. “It shows that the toxicity has not been intensified,” Di Filippo explained.
Next steps
According to Chorilli, the results were positive but these were the first experiences with the nanostructured lipid carrier for this specific application. “We need to do more studies in isolated cells and animals. If the results against glioblastoma multiforme remain good, we could try to find partners for clinical trials with human volunteers,” he said.
The study reported in the article highlighted the potential of lipid nanocarriers in the treatment of brain cancer, he added: “We can use different combinations with other monoclonal antibodies and chemotherapy drugs against other types of cancer. Many years will undoubtedly be needed to complete this research.
Chorilli is studying similar methods for treating infections, such as gastritis and other illnesses caused by the bacterium Helicobacter pylori, in research also supported by FAPESP.
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About the São Paulo Research Foundation (FAPESP)
The São Paulo Research Foundation (FAPESP) is a public institution whose mission is to support scientific research in all areas of knowledge by granting scholarships, fellowships and grants to researchers linked to educational institutions University and Research from the State of São Paulo, Brazil. FAPESP is aware that the best research can only be done by working with the best researchers at the international level. Therefore, it has established partnerships with funding agencies, higher education institutions, private companies and research organizations in other countries known for the quality of their research and has encouraged scientists funded by its grants to further develop their international collaboration. You can find out more about FAPESP at www.FAPESP.br/en and visit the FAPESP news agency at www.agencia.FAPESP.br/en to keep up to date with the latest scientific advances that FAPESP is helping to achieve through to its many programs, awards and research centers. You can also subscribe to the FAPESP press agency at http://agencia.FAPESP.br/subscribe.
. A molecule which combines three distinct technologies against type cancer brain aggressive is tested