Quizartinib, also know as AC220 and AC010220, is an orally available FLT3 STK1 inhibitor with potential antineoplastic activity. Class III receptor tyrosine kinase inhibitor AC220 selectively inhibits class III receptor tyrosine kinases, including FMS-related tyrosine kinase 3 (FLT3 STK1), colony-stimulating factor 1 receptor (CSF1R FMS), stem cell factor receptor (SCFR KIT), and platelet derived growth factor receptors (PDGFRs), resulting in inhibition of ligand-independent leukemic cell proliferation and apoptosis. Mutations in FLT3, resulting in constitutive activation, are the most frequent genetic alterations in acute myeloid leukemia (AML) and occur in approximately one-third of AML cases.
Prostaglandin D2 (PGD2) is a primary enzymatic prostaglandin derived from PGH2 and is abundantly produced in the cerebrospinal fluid (CSF) by the lipocalin-type PGD synthase, and peripherally by myeloid cells such as mast cells and basophils via a hematopoietic-type PGD synthase. PGD2 is chemically unstable and presents challenges for use and analysis due to its brief in vivo half-life. Δ12-PGD2, an initial decomposition product of PGD2, acts as an intermediate in the pathway to Δ12-PGJ2, a cyclopentenone prostaglandin known for its antimitotic and carcinogenic properties. The metabolism of Δ12-PGD2 involves the addition of thiol nucleophiles, a common pathway for many cyclopentenone prostaglandins.
Prostaglandin D2 (PGD2) is one of the five principal prostaglandins enzymatically derived from PGH2. It is abundantly generated in the cerebrospinal fluid (CSF) by lipocalin-type PGD synthase and in peripheral regions by myeloid cells, such as mast cells and basophils, via leukocyte-type PGD synthase. The compound 1,25-trans-PGD2 is an isomer of PGD2, characterized by the alteration of the double bond between carbons 5 and 6 from cis(Z) to trans(E). This trans isomer, found as a 2-5% impurity in most commercial PGD2 bulk drug preparations, is primarily synthesized as an analytical standard to identify and quantify this impurity. Based on existing studies of trans isomers of F-type prostaglandins, 5-trans-PGD2 likely exhibits biological activity comparable to its cis isomer, although no specific published reports confirm this for 5-trans-PGD2.