Working with mice, Johns Hopkins researchers have discovered that weeks of treatment with a repurposed FDA-approved drug halted the growth of — and ultimately left no detectable trace of — brain tumor cells taken from adult human patients.
The scientists targeted a mutation in the IDH1 gene first identified in human brain tumors called gliomas by a team of Johns Hopkins cancer researchers in 2008. This mutation was found in 70 to 80 percent of lower-grade and progressive forms of the brain cancer. The change occurs within a single spot along a string of thousands of genetic coding letters, and is disruptive enough to keep the seemingly innocuous protein from playing its role in converting glucose into energy. Instead, the mutation hijacks the protein to make a new molecule not normally found in the cell, which is apparently a linchpin in the process of forming and maintaining cancer cells.
Encouraged by the new findings, described online Sept. 16 in the open-access journal Oncotarget, the Johns Hopkins researchers say they want to work quickly to design a clinical trial to bring what they learned in mice to humans with gliomas. Despite the growing understanding of IDH1 mutant gliomas, the development of effective therapies has proven challenging, they say.
“Usually in the lab, we’re happy to see a drug slow down tumor growth,” says Alexandra Borodovsky, a graduate student in the Cellular and Molecular Medicine Program at the Johns Hopkins University School of Medicine who performed the experiments. “We never expect tumors to regress, but that is exactly what happened here.”
“This therapy has worked amazingly well in these mice,” says study leader Gregory J. Riggins, M.D., Ph.D., a professor of neurosurgery and oncology at the Johns Hopkins University School of Medicine. “We have spoken with neurosurgeons here, and as soon as possible, we want to start discussing the parameters of a clinical trial to see if this will work in our patients as a follow-up to surgery.”