Design,Synthesis And Biological Activities Of Novel Anhydrophytospingosine Analogs As SphK1 Antagonists

Sphingosine kinase 1（SphK1）is a ATP-dependent lipid kinase which was considered as a key enzyme to catalyze Sphingosine（Sp）to Sphingosine 1-phosphate（S1P）.S1P is an important signaling molecule that regulates the normal physiological functions by activating various signaling pathways in cells.The overexpression of SphK1 can increase the intracellular level of S1P,stimulating excessive cell proliferation,leading to malignant transformation of cells and induction of carcinogenesis.SphK1 activity inhibition can play a role in the treatment of cancers,therefore,SphK1 is an ideal target for cancer treatment.This thesis focused on the structure modification of lead compound Jaspine B which is an bioactive natural product targeted SphK1.The main work included modification of the tetrahydrofuran ring into a tetrahydropyrrole ring,followed by the introduction of some long-chain hydrophobic group at the position 2.A series of reactions were carried out and 17targeted compounds were obtained,16 of which were new compounds.The structures of all these compounds were identified by IR,¹H-NMR,¹³C-NMR,and HR-MS spectra.All of these eighteen 2,3,4-trisubstituted tetrahydropyrrolidins were subjected to docking test,inhibition on kinases and antiproliferative activities against cancer cells.Molecular docking results show that most of the 2,3,4-trisubstituted tetrahydropyrrolidins have a highly similar spatial orientation with the endogenous ligand sphingosine,and their conformation fits well with the ligand binding pocket of SphK1.The amino group,hydroxyl group and hydrophobic long chain on the tetrahydropyrrole ring can form hydrogen bonding or hydrophobic interaction with amino acid residues in the binding pocket,which increase the affinity of the compounds for SphK1.The results of kinase inhibitory activities showed that all of the 2,3,4-trisubstituted tetrahydropyrrolidins had no significant inhibitory effectes on SphK2,and have better selectivity than Jaspine B.Among them,P17(IC₅₀:SphK1=0.8μM,SphK2>100μM)has an inhibitory activity against SphK1 of more than 125 times than that of SphK2.The results of kinase inhibitory activities also verified in accordance with that of the molecular docking study,indicating that molecular simulation has a certain guiding significance for the virtual screening of compounds.The results of anti-cancer cell proliferation activitis indicate that most of the 2,3,4-trisubstituted tetrahydropyrrolidines can exert better anti-proliferative effects on human lung cancer（A549）,human colon cancer（LOVO）,human melanoma（A375）,and human liver cancer（HepG2）cells with high expression of SphK1.Among them,P1 have significant anti-proliferative effects against human lung cancer（A549）(IC₅₀=0.02μM),human colon cancer（LOVO）(IC₅₀=0.05μM),and human liver cancer（HepG2）(IC₅₀=0.02μM)cells.For non-highly expressed human esophageal cancer（TE-1）cells,almost all compounds have no significant antiproliferative activity,which also supports the2,3,4-trisubstituted tetrahydropyrrolidines exert anti-proliferative effect by targeting SphK1.