small molecule inhibitor · BEGINNER LESSON
DMH-1
DMH-1 is a small molecule used in research as an inhibitor of bone morphogenetic protein (BMP) type I receptors and, in one study, as a noncompetitive inhibitor of P-glycoprotein (P-gp). It is measured by how it changes signaling, cell growth, drug accumulation, and enzyme activity in laboratory tests.
What DMH-1 is
DMH-1 is a synthetic small molecule with a defined chemical structure. In the supplied sources, it is described as a selective inhibitor of type I BMP receptors, and it is also reported in one study to inhibit P-glycoprotein, a membrane transporter that pumps certain compounds out of cells. Researchers measure its effects by looking at signaling changes, cell behavior, drug accumulation inside cells, and transporter enzyme activity.
[1] 3.3. Dmh1 Inhibits... [2] 4-[6-[4-(1-Methylethoxy)phenyl]pyrazolo[1,5-a]pyrimidin-3-yl]quinoline [3] DMH1, a small molecule inhibitor of BMP type i receptors, suppresses growth and invasion of lung cancer - PubMed
How it works on BMP signaling
BMP stands for bone morphogenetic protein. BMP signaling is a communication pathway that helps control cell behavior through receptors on the cell surface. Type I BMP receptors pass the signal inward through a kinase domain, a protein region that adds phosphate groups to other proteins. In lung cancer cells, DMH-1 reduced phosphorylation of Smad1/5/8, which are signaling proteins downstream of BMP receptors, and lowered expression of Id1, Id2, and Id3. These changes matched reduced cell growth, migration, invasion, and tumor growth in a xenograft model, which is a tumor grown in an animal for research.
How it works on P-glycoprotein
P-glycoprotein, or P-gp, is a transporter that lowers intracellular drug levels by exporting compounds out of cells. In the reported study, DMH-1 increased the accumulation of Calcein AM and doxorubicin (DNR) inside cells, showing reduced P-gp efflux. Kinetic data showed a lower Vmax, which is the maximum transport rate, without a change in Km, a measure tied to substrate binding. That pattern supports noncompetitive, allosteric inhibition: DMH-1 acts at a site different from the main substrate-binding site. Docking studies suggested binding in the transmembrane domain and possible stabilization of an inward-facing P-gp shape.
Limitations and evidence level
The P-gp findings come from in vitro experiments, meaning controlled tests outside a living body, so they may not fully predict what happens in vivo, inside an organism. The same source says that more validation is needed for the proposed binding site and that chronic toxicity, pharmacokinetics, and drug–drug interactions still need careful study. A second source reports low toxicity in vitro and tolerance at 5 mg/kg in mice, but that does not settle long-term safety.
[1] 3.3. Dmh1 Inhibits... [2] 4-[6-[4-(1-Methylethoxy)phenyl]pyrazolo[1,5-a]pyrimidin-3-yl]quinoline
SEE THE IDEA
DMH-1 studied effects in two laboratory systems
A small molecule tested in research
DMH-1 blocks signaling through the kinase domain
DMH-1 can reduce drug export from cells
Less signaling, less growth, and more intracellular drug retention
DMH-1 interacts with different targets in different studies, leading to reduced BMP signaling or reduced P-gp efflux.
The sources describe one compound with two experimentally observed mechanisms, each measured by specific laboratory readouts.
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Sources and further reading
This general lesson was generated from public source material. It explains a concept; it does not interpret a private paper or provide medical advice.