Biological Activity
PF-543 is a potent, sphingosine-competitive SPHK1 inhibitor for investigating S1P production and sphingolipid signaling. Ki was 3.6 nM; inhibition was competitive with sphingosine, with more than 100-fold selectivity over SphK2.
In Vitro
| Endpoint | Model / conditions / source | Reported result |
|---|---|---|
| Biochemical potency | Sphingosine kinase 1 inhibition. [1] | Ki was 3.6 nM; inhibition was competitive with sphingosine, with more than 100-fold selectivity over SphK2. |
| Cellular lipids | 1483 head-and-neck cancer cells. [1] | S1P decreased approximately tenfold while sphingosine increased. |
| Growth versus target response | Same cellular study. [1] | Despite lipid target engagement, cell growth and survival were not reduced under the reported conditions. |
| Whole-blood assay | Human blood ex vivo. [1] | PF-543 inhibited S1P formation. This finding is distinct from animal antitumor efficacy. |
In Vivo
No compound-specific animal efficacy result is established by the sources summarized here.
Interpretation
S1P depletion does not necessarily translate into cell killing; biochemical and viability endpoints must be kept separate.
