Fluorinated triazole-containing sphingosine analogues. Syntheses and in vitro evaluation as SPHK inhibitors

Targeting dihydroceramide desaturase 1 (Des1): Syntheses of ceramide analogues with a rigid scaffold, inhibitory assays, and AlphaFold2-assisted structural insights reveal cyclopropenone PR280 as a potent inhibitor

Dihydroceramide desaturase 1 (Des1) catalyzes the formation of a CC double bond in dihydroceramide to furnish ceramide. Inhibition of Des1 is related to cell cycle arrest and programmed cell death. The lack of the Des1 crystalline structure, as well as that of a close homologue, hampers the detailed understanding of its inhibition mechanism and difficults the design of new inhibitors, thus making Des1 a strategic target. Based on previous structure-activity studies, different ceramides containing rigid scaffolds were designed. The synthesis and evaluation of these compounds as Des1 inhibitors allowed the identification of PR280 as a better Des 1 inhibitor in vitro (IC50 = 700 nM) than GT11 and XM462, the current reference inhibitors. This cyclopropenone ceramide was obtained in a 6-step synthesis with a 24 % overall yield. The highly confident 3D structure of Des1, recently predicted by AlphaFold2, served as the basis for conducting docking studies of known Des1 inhibitors and the ceramide derivatives synthesized by us in this study. For this purpose, a complete holoprotein structure was previously constructed. This study has allowed a better knowledge of key ligand-enzyme interactions for Des1 inhibitory activity. Furthermore, it sheds some light on the inhibition mechanism of GT11.

SPK1/S1P axis confers gastrointestinal stromal tumors (GISTs) resistance of imatinib

BACKGROUND

Imatinib mesylate (IM) is highly effective in the treatment of gastrointestinal stromal tumors (GISTs). However, the most of GISTs patients develop secondary drug resistance after 1-3 years of IM treatment. The aim of this study was to explore the IM-resistance mechanism via the multi-scope combined with plasma concentration of IM, genetic polymorphisms and plasma sensitive metabolites.

METHODS

This study included a total of 40 GISTs patients who had been regularly treated and not treated with IM. The plasma samples were divided into three experiments, containing therapeutic drug monitoring (TDM), OCT1 genetic polymorphisms and non-targeted metabolomics. According to the data of above three experiments, the IM-resistant cell line, GIST-T1/IMR cells, was constructed for verification the IM-resistance mechanism.

RESULTS

The results of non-targeted metabolomics analysis suggested that the sphingophospholipid metabolic pathway including the SPK1/S1P axis was inferred in IM-insensitive patients with GISTs. A GIST cell line (GIST-T1) was immediately induced as an IM resistance cell model (GIST-T1/IMR) and we found that blocking the signal pathway of SPK1/S1P in the GIST-T1/IMR could sensitize treatment of IM and reverse the IM-resistance.

CONCLUSIONS

Our findings suggest that IM secondary resistance is associated with the elevation of S1P, and blockage the signaling pathway of SPK1/S1P warrants evaluation as a potential therapeutic strategy in IM-resistant GISTs. The design of this study from blood management, group information collection, IM plasma concentration with different elements, identification of sphingolipid metabolism and lastly verification the function of SPK1/S1P in the IM-resistance GISTs cells.

Fluorinated triazoles as privileged potential candidates in drug development—focusing on their biological and pharmaceutical properties

Fluorinated heterocycles have attracted extensive attention not only in organic synthesis but also in pharmaceutical and medicinal sciences due to their enhanced biological activities than their non-fluorinated counterparts. Triazole is a simple five-membered heterocycle with three nitrogen atoms found in both natural and synthetic molecules that impart a broad spectrum of biological properties including but not limited to anticancer, antiproliferative, inhibitory, antiviral, antibacterial, antifungal, antiallergic, and antioxidant properties. In addition, incorporation of fluorine into triazole and its derivatives has been reported to enhance their pharmacological activity, making them promising drug candidates. This mini-review explores the current developments of backbone-fluorinated triazoles and functionalized fluorinated triazoles with established biological activities and pharmacological properties.

Design of Sphingosine Kinases Inhibitors: Challenges and Recent Developments

BACKGROUND

Sphingosine kinases (SphKs) catalyze the phosphorylation of sphingosine to form the bioactive sphingolipid metabolite sphingosine-1-phosphate (S1P). S1P is an important lipid mediator with a wide range of biological functions; it is also involved in a variety of diseases such as inflammatory diseases, Alzheimer's disease and cancer.

METHODS

This review reports the recent advancement in the research of SphKs inhibitors. Our purpose is also to provide a complete overview useful for underlining the features needed to select a specific pharmacological profile.

DISCUSSION

Two distinct mammalian SphK isoforms have been identified, SphK1 and SphK2. These isoforms are encoded by different genes and exhibit distinct subcellular localizations, biochemical properties and functions. SphK1 and SphK2 inhibition can be useful in different pathological conditions.

CONCLUSION

SphK1 and SphK2 have many common features but different and even opposite biological functions. For this reason, several research groups are interested in understanding the therapeutic usefulness of a selective or non-selective inhibitor of SphKs. Moreover, a compensatory mechanism for the two isoforms has been demonstrated, thus leading to the development of dual inhibitors.

Sphk1 promotes ulcerative colitis via activating JAK2/STAT3 signaling pathway

Ulcerative colitis (UC) is a chronic non-specific inflammatory disease of the colon and rectum. The cause of ulcerative colitis is still unclear, although there may be a hereditary factor. SphK1 has been reported to exhibit an inhibitory effect on the occurrence and development of inflammation; however, the association between SphK1 and the progression of UC remains unclear. The aim of the present study was to investigate the effect of Sphk1 on the progression of UC. The proliferation of RAW264.7 cells was determined using a Cell Counting Kit-8 assay and apoptosis was measured using flow cytometry. The levels of pro-inflammatory cytokines secreted by RAW264.7 cells were investigated using ELISA kits and the protein expression levels in RAW264.7 cells were examined by western blotting. A dextran sulfate sodium (DSS)-induced mouse model was established to investigate the effect of SphK1 on the progression of UC in vivo. Overexpression of Sphk1 significantly increased the proliferation and inhibited the apoptosis of RAW264.7 cells. Additionally, overexpression of Sphk1 increased the secretion of pro-inflammatory cytokines and activated the JAK2/STAT3 signaling pathway in RAW264.7 cells, and JSI-124 partially suppressed these effects. Furthermore, SphK1-small interfering RNA or JSI-124 partially rescued lipopolysaccharide-induced proliferation and pro-inflammatory effects on RAW264.7 cells. The SphK1 inhibitor (PF-543) had an inhibitory effect on DSS-induced UC mice. Sphk1 had significant pro-inflammatory effects on the progression of UC, and may thus be a potential novel therapeutic target for the treatment of UC.