More than Just an Immunosuppressant: The Emerging Role of FTY720 as a Novel Inducer of ROS and Apoptosis

Fingolimod hydrochloride (FTY720) is a first-in-class of sphingosine-1-phosphate (S1P) receptor modulator approved to treat multiple sclerosis by its phosphorylated form (FTY720-P). Recently, a novel role of FTY720 as a potential anticancer drug has emerged. One of the anticancer mechanisms of FTY720 involves the induction of reactive oxygen species (ROS) and subsequent apoptosis, which is largely independent of its property as an S1P modulator. ROS have been considered as a double-edged sword in tumor initiation/progression. Intriguingly, prooxidant therapies have attracted much attention due to its efficacy in cancer treatment. These strategies include diverse chemotherapeutic agents and molecular targeted drugs such as sulfasalazine which inhibits the CD44v-xCT (cystine transporter) axis. In this review, we introduce our recent discoveries using a chemical genomics approach to uncover a signaling network relevant to FTY720-mediated ROS signaling and apoptosis, thereby proposing new potential targets for combination therapy as a means to enhance the antitumor efficacy of FTY720 as a ROS generator. We extend our knowledge by summarizing various measures targeting the vulnerability of cancer cells’ defense mechanisms against oxidative stress. Future directions that may lead to the best use of FTY720 and ROS-targeted strategies as a promising cancer treatment are also discussed.

Perspective on FTY720, an Immunosuppressant

FTY720 {fingolimod hydrochloride, 2-amino-2-[2-(4-octylphenyl)ethyl]propane-1,3-diol hydrochloride}, a novel immunosuppressant, was discovered by chemical modification based on the structure activity relationships of ISP-I (myriocin), a metabolite of the fungus Isaria­ sinclairii. This short perspective provides insights to the various strategies available in the literature for the synthesis of FTY720 and its analogues.1 Introduction2 Classification of Immunosuppressive Drugs3 The Rise of FTY7204 Different Synthetic Strategies for FTY7205 Analogues of FTY7206 Binding Studies of FTY7207 Mode of Action8 Conclusion

Crystal structure of fingolimod hydrochloride, C19H34ClNO2

The crystal structure of fingolimod hydrochloride (C19H34ClNO2) has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Fingolimod hydrochloride crystallizes in space group P21/n (#14) with a = 7.137 53(5), b = 5.957 98(4), c = 49.5196(4) Å, β = 91.0808(7)°, V = 2105.46(2) Å3, and Z = 4. The structure consists of a “lipid bilayer” packing. The polar ends of the molecules make O–H···Cl and N–H···Cl hydrogen bonds to the chloride anion, and the octyl side chains pack adjacent to each other. The hydrogen bonds form three types of chains with graph sets C1,2(7), C1,2(7), and C1,2(8). The result is a complex chain of hydrogen bonds parallel to the b-axis. The powder pattern has been submitted to ICDD for inclusion in future releases of the Powder Diffraction File™.