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Cancer Drug Shows Promise for Parkinson's Disease
- Jun 06 2013
A chemotherapy treatment for adults with leukemia may hold potential to treat people with Parkinson’s disease (PD), according to an early study published May 10 in Human Molecular Genetics. In mice, the drug was able to reduce levels of a harmful protein in the brain and improve motor symptoms. Scientists have not yet determined the drug’s potential for people living with PD, but this early study in mice offers hope.
In PD, the brain is characterized by clumps of a protein alpha-synuclein, which aggregate within neurons. An enzyme called c-Abl also appears to increase in activity in the brain cells of people with PD. Charbel E.-H. Moussa, M.B., Ph.D., and his colleagues at the Georgetown University Medical Center in Washington, DC, thought the two might be related — that c-Abl might be linked to the build-up of alpha-synuclein. Further, they predicted that they might be able to treat PD by blocking c-Abl with a drug already available for leukemia.
In 2007, the US Food and Drug Administration (FDA) approved of a leukemia treatment called nilotinib that blocks the function c-Abl. This drug also penetrates the brain in the doses that are currently approved for leukemia. Dr. Moussa and his team treated mice with parkinsonian symptoms with the drug and observed its effects. They also conducted other experiments in the lab to understand how c-Abl and alpha-synuclein interact.
- When studying the mice and autopsy mouse brain samples, Dr. Moussa and colleagues found that c-Abl and alpha-synuclein seemed connected. When c-Abl was active, levels of alpha-synuclein protein increased.
- Nilotinib decreased alpha-synuclein levels in the brains of mice over the course of three months.
- The motor symptoms of mice had initially deteriorated, but this effect was reversed with nilotinib injections.
What Does It Mean?
This study demonstrates that a drug already on the market for leukemia, nilotinib may have potential for people with Parkinson’s disease.
In this initial study in mice, the drug was able to block the work of the enzyme c-Abl. In turn, cells were able to continue ridding themselves of harmful alpha-synuclein and animals’ motor symptoms improved. This method of treatment may work in PD, researchers say, because of the slow and progressive nature of the disease.
Dr. Moussa’s team suggests that the results be treated with cautious optimism. First, the study was conducted on mice genetically engineered to have protein accumulation seen in PD, because of genetic mutations, as opposed to in people who have alpha-synuclein accumulation without the genetic mutations. Further, nilotinib has a number of side effects to be considered. In people with leukemia, it causes gastrointestinal complications, vomiting, nausea and dizziness. Moreover, nilotinib can also suppress bone marrow production and cause heart irregularities that could lead to sudden death. However, the scientists suggest that some of its toxic effects might be tempered by using nilotinib in low doses for extended periods of time.
On the plus side, this drug has already been tested and proven safe in clinical trials for leukemia, which could expedite its use in PD. But before it’s an option for PD, the next step will be to conduct small clinical trials to evaluate nilotinib’s safety in people with PD and its potential for easing motor symptoms of PD.
Reference: Hebron ML, Lonskaya I, Moussa CEH (2013) Nilotinib reverses loss of dopamine neurons and improves motor behavior via autophagic degradation of α-synuclein in Parkinson's disease models. Human Molecular Genetics. Advance Access published May 10, 2013. DOI: 10.1093/hmg/ddt192 http://dx.doi.org/10.1093/hmg/ddt192
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Source Date: Jun 06 2013