Scientists find a new weak point in the cells that drive a hard-to-treat blood cancer

High-risk MDS (myelodysplastic syndromes) is a blood cancer that mostly strikes older adults. It cripples the bone marrow's ability to make healthy red cells, white cells, and platelets, leaving patients with severe anemia, frequent infections, and a real, near-term risk of progression to acute myeloid leukemia (AML), a fast-moving cancer of the same tissue. About 10,000 to 20,000 people in the United States are diagnosed with MDS each year, and current treatment options for the high-risk form are blunt: the only curative path, a stem cell transplant, is too toxic for many older patients to survive. That gap is the reason researchers keep hunting for a vulnerability they can see and aim at.

A [study published this month in Blood Cancer Discovery](https://aacrjournals.org/bloodcancerdiscov/article-abstract/7/5/796/787646/The-Nicotinamide-Salvage-Pathway-Is-a-Metabolic?redirectedFrom=fulltext) has identified one. The work, led by researchers at the University of Colorado Anschutz, maps a specific, narrowly aimed weak point in the cancer-driving stem cells: a single fuel-maintenance pathway that healthy blood-forming cells barely need.

The pathway centers on a molecule called NAD, which cells use to shuttle the chemistry of turning food into usable energy. Most cells can make NAD several ways, but the most direct route runs through an enzyme called NAMPT, the rate-limiting step in what's called the nicotinamide salvage pathway. Picture NAMPT as the bottleneck on a single supply line.

The team found that the stem cells driving high-risk MDS are unusually dependent on that supply line. The cancer-driving cells showed higher oxygen consumption, more of the molecular machinery that uses NAD to make energy, and an increased abundance of NADH dehydrogenases, the protein complexes that sit at the start of the cell's main energy-producing cascade, compared with healthy blood-forming stem cells taken from the same patients. When the team blocked NAMPT, the cancer-driving cells lost their ability to consume oxygen, while healthy cells adapted. That asymmetry, the cancer cells can't switch over, the healthy ones can, is the kind of selectivity drug developers spend years trying to find.

"What we found is that these cells actually use energy in different ways than normal stem cells do," said Eric M. Pietras, PhD, associate professor in the Division of Hematology at the University of Colorado Anschutz, a co-lead author of the study. The institutional release describes the finding as a "potential new target" for treatment.

The selectivity signal was measured in primary cells from patients in the lab, not in animal models or human trials. NAMPT inhibitors exist as a drug class; one, FK866, has been tested in cancer patients before, with documented hematologic toxicity, the very effect an MDS therapy would have to avoid. The open question is whether the selectivity the team observed in primary cells holds up in living systems, and whether a drug can be designed to widen the gap between the cancer-driving cells and the healthy ones they're supposed to spare. Reporting on the finding describes it as an "energy addiction"; the cleaner read is that the cancer-driving cells have an unusually narrow fuel-maintenance bottleneck, and the bottleneck is now visible enough to aim at.

For a field that has spent decades trying to hit a moving target, a peer-reviewed map of a single, named, druggable weakness in the cells that actually drive high-risk MDS is a real narrowing of the search. The next step is the work most people will never see but the work that decides whether this finding becomes a treatment: animal models, dose-finding, and the long search for a NAMPT-blocking drug that can be tuned to widen the gap the cell work has just measured.