The cytosolic thioredoxin redox system composed of thioredoxin-1 and the NADPH-dependent thioredoxin reductase-1 reductase is an important regulator of cell growth and survival. Thioredoxin-1 is overexpressed in many human tumors where it is associated with increased cell proliferation, decreased apoptosis, and decreased patient survival. We hypothesized that thioredoxin reductase-1 provides a target to inhibit the activity of overexpressed thioredoxin-1 for the development of novel anticancer agents. We found that the naphthoquinone spiroketal fungal metabolite palmarumycin CP1 is a potent inhibitor of thioredoxin reductase-1, but attempts to exploit the activity of palmarumycin CP1 analogues as antitumor agents in vivo were hampered by their insolubility. We have therefore developed PX-916, a water-soluble prodrug of a palmarumycin CP1 analogue. PX-916 rapidly releases the parent compound at physiologic pH and in plasma but is stable at acid pH, allowing its i.v. administration. PX-916 is a potent inhibitor of purified human thioredoxin reductase-1 and of thioredoxin reductase-1 activity in cells and tumor xenografts when given to mice and inhibits the downstream targets of thioredoxin-1 signaling, hypoxiainducible factor-1A, and vascular endothelial growth factor in tumors. PX-916 showed excellent antitumor activity against several animal tumor models with some cures. Thus, the study shows that water-soluble inhibitors of thioredoxin reductase-1, such as PX-916, can block thioredoxin-1 signaling in tumors producing marked inhibition of tumor growth. [Mol Cancer Ther 2006; 5(3):630 -6]

Spiroketal naphthodecalins are readily assembled by Barton's base mediated Ullmann binaphthyl ether coupling, Dakin reactions and hypervalent iodine spirocyclization. The core structures can be further diversified by enone addition and Stille coupling reactions. Nanomolar inhibitors for the Trx/TrxR redox control system were prepared by this approach and compared to series of natural product isolates. Cytotoxicity in MCF-7 cell assays ranged from an IC50 of 1.6 to >100 microM.

HYD was shown to be an efficacious treatment for CLBP in this study. There were no new or unexpected safety concerns detected.

The Janus kinases (JAKs) are involved in multiple signaling networks relevant to inflammatory diseases, and inhibition of one or more members of this class may modulate disease activity or progression. We optimized a new inhibitor scaffold, 3-amido-5-cyclopropylpyrrolopyrazines, to a potent example with reasonable kinome selectivity, including selectivity for JAK3 versus JAK1, and good biopharmaceutical properties. Evaluation of this analogue in cellular and in vivo models confirmed functional selectivity for modulation of a JAK3/JAK1-dependent IL-2 stimulated pathway over a JAK1/JAK2/Tyk2-dependent IL-6 stimulated pathway.

The total syntheses of gamma-lycorane and (+/-)-1-deoxylycorine were accomplished using an intramolecular Diels-Alder cycloaddition of a furanyl carbamate as the key step. The initially formed [4+2]-cycloadduct undergoes nitrogen-assisted ring opening followed by deprotonation/reprotonation of the resulting zwitterion to give a rearranged hexahydroindolinone. The stereochemical outcome of the IMDAF cycloaddition has the side arm of the tethered alkenyl group oriented syn with respect to the oxygen bridge. The key intermediate used in both syntheses corresponds to hexahydroindolinone 20. Removal of the t-Boc group in 20 followed by reaction with 6-iodobenzo[1,3]dioxole-5-carbonyl chloride afforded enamide 22. Treatment of this compound with Pd(OAc)(2) employing the Jeffrey modification of the Heck reaction provided the galanthan tetracycle 24 in good yield. Compound 24 was subsequently converted into (+/-)-gamma-lycorane using a four-step procedure to establish the cis-B,C-ring junction. A radical-based cyclization of the related enamide 33 was used for the synthesis of 1-deoxylycorine. Heating a benzene solution of 33 with AIBN and n-Bu(3)SnH at reflux gave the tetracyclic compound 38 possessing the requisite trans fusion between rings B and C in good yield. After hydrolysis and oxidation of 38 to 40, an oxidative decarboxylation reaction was used to provide the C(2)(-)C(3)(-)C(12) allylic alcohol unit characteristic of the lycorine alkaloids. The resulting enone was eventually transformed into (+/-)-1-deoxylycorine via known synthetic intermediates.