Development of water soluble derivatives of cis-3, 4′, 5-trimethoxy-3′-aminostilbene for optimization and use in cancer therapy

Topical delivery of 3,5,4'-trimethoxy-trans-stilbene-loaded microemulsion-based hydrogel for the treatment of osteoarthritis in a rabbit model

The aim of this study was to develop a microemulsion-based hydrogel (MBH) formulation of 3,5,4'-trimethoxy-trans-stilbene (BTM) as topical delivery system for the treatment of osteoarthritis (OA). The pseudo-ternary phase diagrams were constructed to optimize the microemulsion (ME) formulation. The ME formulation containing 18.8% Cremopher EL35 (surfactant), 9.4% Transcutol HP (co-surfactant), 3.1% LABRAFIL M 1944 CS (oil), and 68.7% water was selected. The obtained BTM-loaded ME (BTM-ME) had a spherical morphology (17.5 ± 1.4 nm), with polydispersity index (PDI) value of 0.068 ± 0.016 and zeta potential of - 11.8 ± 0.5 mV, and was converted into BTM-loaded MBH (BTM-MBH) using Carbopol 940. Ex vivo skin permeation study showed that both ME and MBH formulations significantly enhanced the amount of BTM permeated. The cumulative amount of BTM permeated after 12 h (Q₁₂) for ME, and MBH formulations were 3.25- and 1.96-fold higher than that for emulsion gel (EG). Pharmacokinetic study showed that the AUC of BTM suspension (oral) was three times higher than that of BTM-MBH (topical). Topical delivery of BTM-MBH demonstrated remarkable anti-OA effect in a rabbit model of OA induced by papain, with decreased levels of pro-inflammatory cytokines. The developed MBH formulation might be a promising strategy for topical delivery of BTM for treatment of OA.

Targeting the colchicine site in tubulin through cyclohexanedione derivatives

Cyclohexanedione derivatives, a new family of colchicine-site binders, have been further explored with the aid of docking studies, resulting in compounds with improved solubility and K_a value for tubulin.

Development of hemiasterlin derivatives as potential anticancer agents that inhibit tubulin polymerization and synergize with a stilbene tubulin inhibitor

Hemiasterlins are cytotoxic tripeptides with antimicrotubule activity originally isolated from marine sponges. We have developed new hemiasterlin derivatives BF65 and BF78 that are highly potent to induce cancer cell death in the low nanomolar range. Examination of their mechanisms of cell cycle arrest and disruption of microtubules revealed an unusual characteristic in addition to anti-tubulin effect. Immunofluorescence staining revealed that A549 lung carcinoma cells treated with BF65 or BF78 exhibited both monopolar and multipolar mitotic spindles. Centrosomes were separated with short spindle microtubules in cells with multipolar spindles. In vitro tubulin polymerization assay confirmed that both BF65 and BF78 were highly potent to inhibit tubulin polymerization. These two compounds induced the formation of monoastral spindles suggesting that they might be inhibitors of mitotic kinesins such as KSP/Eg5. However, kinetic measurement of microtubule activated kinesin ATPase activity demonstrated that unlike the positive control monastrol, neither BF65 nor BF78 suppressed KSP/Eg5 activity. Hence the effect may be a variant form of tubulin inhibition. Similar to vinca alkaloids, BF compounds synergized with a colchicine site microtubule inhibitor stilbene 5c both in vitro and in vivo, which may provide a potential drug combination in the future clinical application.

Hydropathic analysis and biological evaluation of stilbene derivatives as colchicine site microtubule inhibitors with anti-leukemic activity

The crucial role of the microtubule in cell division has identified tubulin as a target for the development of therapeutics for cancer; in particular, tubulin is a target for antineoplastic agents that act by interfering with the dynamic stability of microtubules. A molecular modeling study was carried out to accurately represent the complex structure and the binding mode of a new class of stilbene-based tubulin inhibitors that bind at the alphabeta-tubulin colchicine site. Computational docking along with HINT (Hydropathic INTeractions) score analysis fitted these inhibitors into the colchicine site and revealed detailed structure-activity information useful for inhibitor design. Quantitative analysis of the results was in good agreement with the in vitro antiproliferative activity of these derivatives (ranging from 3 nM to 100 muM) such that calculated and measured free energies of binding correlate with an r(2) of 0.89 (standard error +/- 0.85 kcal mol(-1)). This correlation suggests that the activity of unknown compounds may be predicted.