ws-6

WS6, a β cell proliferation inducer, regulates Erb3 binding protein-1 (EBP1) and the IκB kinase pathway.

WS-691 is a highly Potent and Orally Active ABCB1 Modulator. WS-691 significantly increased sensitization of ABCB1-overexpressed SW620/Ad300 cells to paclitaxel (PTX) (IC50 = 22.02 nM). WS-691 significantly increased the intracellular concentration of PTX and [3H]-PTX while decreasing the efflux of [3H]- PTX in SW620/Ad300 cells by inhibiting the efflux function of ABCB1. WS-691 could stabilize ABCB1 by directly binding to ABCB1 WS-691 increased the sensitivity of SW620/Ad300 cells to PTX in vivo without observed toxicity.

Istaroxime, also known as PST-2744, is a positive inotropic agent that mediates its action through inhibition of sodium/potassium adenosine triphosphatase (Na+/K+ ATPase). Na+/K+ ATPase inhibition increases intracellular sodium levels, which reverses the driving force of the sodium/calcium exchanger, inhibiting calcium extrusion and possibly facilitating calcium entry. Additionally, Istaroxime increases intracellular calcium by improving the efficacy by which intracellular calcium triggers sarcoplasmic reticulum calcium release, and by accelerating the inactivation state of L-type calcium channels, which allow for calcium influx.

PC-046 is a potent tubulin-binding agent, which was originally identified for development based on selective activity in deleted in pancreas cancer locus 4 (DPC4/SMAD4) deficient tumors. PC-046 has growth inhibitory activity in a variety of tumor types in vitro, and efficacy in SCID mice was shown in human tumor xenografts of MV-4-11 acute myeloid leukemia, MM.1S multiple myeloma, and DU-145 prostate cancer. Pharmacokinetic studies demonstrated relatively high oral bioavailability (71 %) with distribution to both plasma and bone marrow. No myelosuppression was seen in non-tumor bearing SCID mice given a single dose just under the acute lethal dose. The COMPARE algorithm in the NCI-60 cell line panel demonstrated that PC-046 closely correlated to other known tubulin destabilizing agents (correlation coefficients ≈0.7 for vincristine and vinblastine). Mechanism of action studies showed cell cycle arrest in metaphase and inhibition of tubulin polymerization. Overall, these studi......