Inhibiting a malfunctioning
immune system pathway can kill diseased cells from patients with
myelodysplastic syndrome (MDS), according to study results published July 8, 2013, in Cancer Cell.
In people with
MDS, blood stem cells fail to mature into healthy red or white blood cells,
which can lead to infections, anemia, bleeding disorders or acute myeloid
leukemia (AML). MDS can affect children
but is more common in people over age 60.
findings, based on laboratory tests involving mouse models and human MDS cells,
suggest a new molecular target for drug designs. Currently the only cure for
MDS is bone marrow transplant.
“Not only does
our research implicate errant immune system signaling in MDS cells, it strongly
indicates that inhibiting the function of this hijacked immune pathway may
become an effective treatment option for MDS,” says Daniel
Starczynowski, PhD, lead
researcher and a member of the Division of Experimental Hematology and
Cancer Biology at
The research team
verified that the immune system enzyme IRAK1 (Interleukin Receptor Associated
Kinase-1) is highly over-expressed and hyper-activated in about 25 percent of
MDS/AML cells. Further testing revealed that IRAK-Inh -- a small-molecule
inhibitor of IRAK1 originally developed as a potential treatment for chronic inflammation -- was
effective at slowing disease progression.
treatment did not overcome the effects of a pro-cancer survival gene called
BCL2. In response, researchers tested IRAK-Inh in combination with an inhibitor
of BCL2 called ABT-263. The combination treatment effectively killed MDS cells
without harming normal blood cells.
cautioned that laboratory successes do not necessarily translate into safe and
effective clinical treatments. Even if found to be effective, the potential
treatment may not benefit all people with MDS because IRAK1 is thought to be
overexpressed only in a subset of MDS patients.