CEO of the Saga Medical Center KOSEIKAN and President Emeritus, Chiba Cancer Center
20 Feb 2014
Summary Blog post announcing a breakthrough in the search for a new treatment for neuroblastoma, written by Dr. Akira Nakagawara, principal investigator for Help Fight Childhood Cancer
Today, thanks to advances in modern medicine, 80% of children diagnosed with cancer are cured. But the prognosis is not nearly as good for children with neuroblastoma, the most common form of cancer diagnosed in infants. Neuroblastoma is a tumor of peripheral nerve tissues that often starts in the adrenal glands and sympathetic ganglia of the neck, chest, or abdomen, and affects approximately one in 8,000 children in the United States and Japan.
More than half of neuroblastoma cases are classified as high risk, and only 30% of these children are cured – a rate that has not improved for two decades. New treatments are urgently needed for this dangerous disease.
Our research team at the Chiba Cancer Center in Japan has been working to develop a new treatment for neuroblastoma. With the help of volunteers participating in the IBM World Community Grid initiative, we have just discovered seven new drug candidates that could potentially be used in new medicines that fight childhood neuroblastoma. These drug candidates work by activating a self-destruct mechanism present in neuroblastoma cancer cells, killing them without affecting healthy cells.
Neuroblastoma cells have a receptor on their surfaces called TrkB. When molecules bind to the TrkB receptor and inhibit its function, a tumor suppressor gene called p53 is activated, causing the neuroblastoma cell to self-destruct in a process called apoptosis. Apoptosis is one of the body's natural processes, and ordinarily helps to eliminate damaged cells before they can form a tumor. However, the TrkB receptor in neuroblastoma suppresses this self-destruct function. A similar TrkB process is involved when many adult cancers, including breast, lung, pancreatic, prostate, and colon cancers, metastasize (i.e. spread beyond an initial site). This means our findings may have implications for treating adult cancers as well.
Our strategy was to search for small molecules that would bind to and inhibit the TrkB receptor on cancer cells. There were millions of potential molecules to examine, making it infeasible to synthesize and test each of them in the laboratory. Instead, we partnered with World Community Grid to create the Help Fight Childhood Cancer project, using computer-based modeling on a massive scale to conduct this search. With the help of over 200,000 volunteers around the world contributing their spare computing power, we screened three million molecules in just two years – a process that would have taken more than 55,000 years on a single computer – and identified seven promising drug candidates for further study.
After additional laboratory testing, we have discovered that the seven drug candidates are very effective at destroying neuroblastoma tumors in mice, even at very low dosages, with no immediately apparent side effects. These results have been published in the peer-reviewed journal Cancer Medicine, available online since January 2014.
Based on these very promising findings, we are now seeking a pharmaceutical partner to collaborate on the further development and testing needed to produce an approved medicine.
This breakthrough was made possible by the support of volunteers around the world who donated their computing power through World Community Grid. On behalf of our research team, I would like to thank World Community Grid volunteers from the bottom of my heart.
Akira Nakagawara, MD, PhD, President, Chiba Cancer Center
我々の戦略は、がん細胞上のTrkB 受容体と結合し阻害する小さな分子を見つけることだった。研究対象としては何千もの分子があったが、それをすべて研究室で結合させテストするのは不可能であった。我々は、IBM World Community Grid と組み、｢ファイト！小児がんプロジェクト (Help Fight Childhood Cancer project) ｣を開始し、この大規模の研究を行うためのコンピューター・ベースのモデリングを作った。200,000人以上の世界中のボランティアの方々がコンピューターの空いている処理能力を提供してくださり、わずか2年で300万個の低分子化合物をスクリーニングすることができた。これは、単体のコンピューターだったら、55,000年もかかると予測されているものだ。その結果、将来の研究につながる画期的な7つの新薬候補を見つけだした。
研究所での更なるテストの後、7つの新薬候補はマウスにおける神経芽腫・腫瘍の増殖を、比較的低濃度の投薬により、周辺組織にダメージを与えることなく、抑制することも見出した。この発見は、Cancer Medicine 誌から、2014年1月に on-lineで事前発表されている。