Identification of Quinolinones as Antivirals against Venezuelan Equine Encephalitis Virus.

Venezuelan equine encephalitis virus (VEEV) is a reemerging alphavirus that can cause encephalitis resulting in severe human morbidity and mortality. Using a high-throughput cell-based screen, we identified a quinolinone compound that protected against VEEV-induced cytopathic effects. Analysis of viral replication in cells identified several quinolinone compounds with potent inhibitory activity against vaccine and virulent strains of VEEV. These quinolinones also displayed inhibitory activity against additional alphaviruses, such as Mayaro virus and Ross River virus, although the potency was greatly reduced. Time-of-addition studies indicated that these compounds inhibit the early-to-mid stage of viral replication. Deep sequencing and reverse genetics studies identified two unique resistance mutations in the nsP2 gene (Y102S/C; stalk domain) that conferred VEEV resistance on this chemical series. Moreover, introduction of a K102Y mutation into the nsP2 gene enhanced the sensitivity of chikungunya virus (CHIKV) to this chemical series. Computational modeling of CHIKV and VEEV nsP2 identified a highly probable docking alignment for the quinolinone compounds that require a tyrosine residue at position 102 within the helicase stalk domain. These studies identified a class of compounds with antiviral activity against VEEV and other alphaviruses and provide further evidence that therapeutics targeting nsP2 may be useful against alphavirus infection.

A biomimetic approach for enhancing the in vivo half-life of peptides.

The tremendous therapeutic potential of peptides has not yet been realized, mainly owing to their short in vivo half-life. Although conjugation to macromolecules has been a mainstay approach for enhancing protein half-life, the steric hindrance of macromolecules often harms the binding of peptides to target receptors, compromising the in vivo efficacy. Here we report a new strategy for enhancing the in vivo half-life of peptides without compromising their potency. Our approach involves endowing peptides with a small molecule that binds reversibly to the serum protein transthyretin. Although there are a few molecules that bind albumin reversibly, we are unaware of designed small molecules that reversibly bind other serum proteins and are used for half-life extension in vivo. We show here that our strategy was effective in enhancing the half-life of an agonist for GnRH receptor while maintaining its binding affinity, which was translated into superior in vivo efficacy.

Dioxol and dihydrodioxin analogs of 2- and 3-phenylacetonitriles as potent anti-cancer agents with nanomolar activity against a variety of human cancer cells.

A small library of (Z)-2-(benzo[d][1,3]dioxol-5-yl) and (Z)-2,3-dihydrobenzo[b][1,4]dioxin-6-yl analogs of 2- and 3-phenylacetonitriles has been synthesized and evaluated for their anti-cancer activities against a panel of 60 human cancer cell lines. The dihydrodioxin analog 3j and dioxol analogs 5e and 7e exhibited the most potent anti-cancer activity of all the analogs synthesized in this study, with GI50 values of <100 nM against almost all of the cell lines in the human cancer cell panel. Of these three, only compound 3j inhibited tubulin polymerization to any degree in vitro. The binding modes of 3j and the structurally related tubulin-inhibitor DMU-212 were determined by virtual docking studies with tubulin dimer. Compound 3j docked at the colchicine-binding site at the dimer interface of tubulin. The Full-Fitness (FF) score of 3j was observed to be substantially higher than DMU-212, which agrees well with the observed anti-cancer potency (GI50 values). The mechanism by which dioxol analogs 5e and 7e exert their cytotoxic effects remains unknown at this stage, but it is unlikely that they affect tubulin dynamics. Nevertheless, these findings suggest that both dioxol and dihydrodioxin analogs of phenylacrylonitrile may have potential for development as clinical candidates to treat a variety of human cancers.

Novel resveratrol-based substrates for human hepatic, renal, and intestinal UDP-glucuronosyltransferases.

Trans-Resveratrol (tRes) has been shown to have powerful antioxidant, anti-inflammatory, anticarcinogenic, and antiaging properties; however, its use as a therapeutic agent is limited by its rapid metabolism into its conjugated forms by UDP-glucuronosyltransferases (UGTs). The aim of the current study was to test the hypothesis that the limited bioavailability of tRes can be improved by modifying its structure to create analogs which would be glucuronidated at a lower rate than tRes itself. In this work, three synthetic stilbenoids, (E)-3-(3-hydroxy-4-methoxyphenyl)-2-(3,4,5-trimethoxyphenyl)acrylic acid (NI-12a), (E)-2,4-dimethoxy-6-(4-methoxystyryl)benzaldehyde oxime (NI-ST-05), and (E)-4-(3,5-dimethoxystyryl)-2,6-dinitrophenol (DNR-1), have been designed based on the structure of tRes and synthesized in our laboratory. UGTs recognize and glucuronidate tRes at each of the 3 hydroxyl groups attached to its aromatic rings. Therefore, each of the above compounds was designed with the majority of the hydroxyl groups blocked by methylation and the addition of other novel functional groups as part of a drug optimization program. The activities of recombinant human UGTs from the 1A and 2B families were examined for their capacity to metabolize these compounds. Glucuronide formation was identified using HPLC and verified by ß-glucuronidase hydrolysis and LC-MS/MS analysis. NI-12a was glucuronidated at both the -COOH and -OH functions, NI-ST-05 formed a novel N-O-glucuronide, and no product was observed for DNR-1. NI-12a is primarily metabolized by the hepatic and renal enzyme UGT1A9, whereas NI-ST-05 is primarily metabolized by an extrahepatic enzyme, UGT1A10, with apparent Km values of 240 and 6.2 µM, respectively. The involvement of hepatic and intestinal UGTs in the metabolism of both compounds was further confirmed using a panel of human liver and intestinal microsomes, and high individual variation in activity was demonstrated between donors. In summary, these studies clearly establish that modified, tRes-based stilbenoids may be preferable alternatives to tRes itself due to increased bioavailability via altered conjugation.

Synthesis and anti-proliferative activity of aromatic substituted 5-((1-benzyl-1H-indol-3-yl)methylene)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione analogs against human tumor cell lines.

Based on previous SAR studies on N-benzylindole and barbituric acid hybrid molecules, we have synthesized a series of aromatic substituted 5-((1-benzyl-1H-indol-3-yl)methylene)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione analogs (3a-i) and evaluated them for their in vitro growth inhibition and cytotoxicity against a panel of 60 human tumor cell lines. Compounds 3c, 3d, 3f and 3g were identified as highly potent anti-proliferative compounds against ovarian, renal and breast cancer cell lines with GI50 values in low the nanomolar range. The 4-methoxy-N-benzyl analog (3d) was the most active compound with GI50 values of 20 nM and 40 nM against OVCAR-5 ovarian cancer cells and MDA-MB-468 breast cancer cells, respectively. Two other analogs, 3c (the 4-methyl-N-benzyl analog) and 3g (the 4-fluoro-N-benzyl analog) exhibited equimolar potency against MDA-MB-468 cells GI50=30 nM). Analog 3f (the 4-chloro-N-benzyl analog) exhibited a GI50 value of 40 nM against renal cancer cell line A498. These results suggest that aromatic substituted N-benzylindole dimethylbarbituric acid hybrids may have potential for development as clinical candidates to treat a variety of solid tumors.

Anti-cancer activity of carbamate derivatives of melampomagnolide B.

Melampomagnolide B (MMB) is a natural sesquiterpene structurally related to parthenolide (PTL). We have shown that MMB exhibits anti-leukemic properties similar to PTL. Unlike PTL, the presence of a primary hydroxyl group in the MMB molecule allows the opportunity for examining the biological activity of a variety of conjugated analogs of MMB. We have now synthesized a series of carbamate analogs of MMB and evaluated these derivatives for anti-cancer activity against a panel of sixty human cancer cell lines. Analogs 6a and 6e exhibited promising anti-leukemic activity against human leukemia cell line CCRF-CEM with GI50 values of 680 and 620 nM, respectively. Analog 6a also showed GI50 values of 1.98 and 1.38 µM respectively, against RPMI-8226 and SR leukemia cell lines and GI50 values of 460 and 570 nM against MDA-MB-435 melanoma and MDA-MB-468 breast cancer cell lines, respectively. Analog 6e had GI50 values of 650 and 900 nM against HOP-92 non-small cell lung and RXF 393 renal cancer cell lines.

L-Proline catalyzed one-step synthesis of 4,5-diaryl-2H-1,2,3-triazoles from heteroaryl cyanostilbenes via [3+2] cycloaddition of azide.

Use of a novel reagent has been established for the synthesis of a series of 4,5-diaryl-2H-1,2,3-triazoles (6a-i and 9a-e) from cyanostilbene analogs of benzo[b]thiophene, benzo[b]furan and indole, catalyzed by L-proline via Lewis base-catalyzed one-step [3+2]cycloaddition of azide. This method provides an efficient, simple and environmentally benign procedure that affords good yields and relatively short reaction times.

Crystal structure of 4,5-bis-(3,4,5-tri-meth-oxy-phen-yl)-2H-1,2,3-triazole methanol monosolvate.

The title compound, C20H23N3O6·CH3OH, was synthesized by [3 + 2] cyclo-addition of (Z)-2,3-bis-(3,4,5-tri-meth-oxy-phen-yl)acrylo-nitrile with sodium azide and ammonium chloride in DMF/water. The central nitro-gen of the triazole ring is protonated. The dihedral angles between the triazole ring and the 3,4,5-tri-meth-oxy-phenyl ring planes are 34.31 (4) and 45.03 (5)°, while that between the 3,4,5-tri-meth-oxy-phenyl rings is 51.87 (5)°. In the crystal, the mol-ecules, along with two methanol solvent mol-ecules are linked into an R (4) 4(10) centrosymmetric dimer by N-H⋯O and O-H⋯N hydrogen bonds.

Comparison of crystal structures of 4-(benzo[b]thio-phen-2-yl)-5-(3,4,5-tri-meth-oxy-phen-yl)-2H-1,2,3-triazole and 4-(benzo[b]thio-phen-2-yl)-2-methyl-5-(3,4,5-tri-meth-oxy-phen-yl)-2H-1,2,3-triazole.

The title compound, C19H17N3O3S (I), was prepared by a [3 + 2]cyclo-addition azide condensation reaction using sodium azide and l-proline as a Lewis base catalyst. N-Methyl-ation of compound (I) using CH3I gave compound (II), C20H19N3O3S. The benzo-thio-phene ring systems in (I) and (II) are almost planar, with r.m.s deviations from the mean plane = 0.0205 (14) in (I) and 0.016 (2) Šin (II). In (I) and (II), the triazole rings make dihedral angles of 32.68 (5) and 10.43 (8)°, respectively, with the mean planes of the benzo-thio-phene ring systems. The trimeth-oxy phenyl rings make dihedral angles with the benzo-thio-phene rings of 38.48 (4) in (I) and 60.43 (5)° in (II). In the crystal of (I), the mol-ecules are linked into chains by N-H⋯O hydrogen bonds with R (2) 1(5) ring motifs. After the N-methyl-ation of structure (I), no hydrogen-bonding inter-actions were observed for structure (II). The crystal structure of (II) has a minor component of disorder that corresponds to a 180° flip of the benzo-thio-phene ring system [occupancy ratio 0.9363 (14):0.0637 (14)].

Monosuccinate ester of melampomagnolide B.

THE TITLE MONOSUCCINATE DERIVATIVE OF MELAMPOMAGNOLIDE B [SYSTEMATIC NAME: 4-(((1aR,7aS,10aS,10bS,E)-1a-methyl-8-meth-yl-ene-9-oxo-1a,2,3,6,7,7a,8,9,10a,10b-deca-hydro-oxireno[2',3':9,10]cyclo-deca-[1,2-b]furan-5-yl)meth-oxy)-4-oxo-butan-oic acid], C19H24O7, was obtained from the reaction of melampomagnolide B with succinic anhydride under nucleophilic addition reaction conditions. The mol-ecule is built up from fused ten-, five- (lactone) and three-membered (epoxide) rings. The inter-nal double bond in the ten-membered ring has the cis geometry (i.e. it is the E isomer). The lactone ring has an envelope-type conformation, with the (chiral) C atom opposite the lactone O atoms as the flap atom. In the crystal, O-H⋯O hydrogen bonds link the mol-ecules into chains parallel to the b-axis direction.

Evaluation of (Z)-2-((1-benzyl-1H-indol-3-yl)methylene)-quinuclidin-3-one analogues as novel, high affinity ligands for CB1 and CB2 cannabinoid receptors.

A small library of N-benzyl indolequinuclidinone (IQD) analogs has been identified as a novel class of cannabinoid ligands. The affinity and selectivity of these IQDs for the two established cannabinoid receptor subtypes, CB1 and CB2, was evaluated. Compounds 8 (R=R(2)=H, R(1)=F) and 13 (R=COOCH3, R(1)=R(2)=H) exhibited high affinity for CB2 receptors with Ki values of 1.33 and 2.50 nM, respectively, and had lower affinities for the CB1 receptor (Ki values of 9.23 and 85.7 nM, respectively). Compound 13 had the highest selectivity of all the compounds examined, and represents a potent cannabinoid ligand with 34-times greater selectivity for CB2R over CB1R. These findings are significant for future drug development, given recent reports demonstrating beneficial use of cannabinoid ligands in a wide variety of human disease states including drug abuse, depression, schizophrenia, inflammation, chronic pain, obesity, osteoporosis and cancer.

(Z)-2-{2,4-Dimeth-oxy-6-[(E)-4-meth-oxy-styr-yl]benzyl-idene}quinuclidin-3-one.

The crystal structure of the title compound, C(25)H(27)NO(4), shows the presence of a double bond with Z geometry which connects the quinuclidin-3-one ring and the trimeth-oxy-resveratrol moiety. The dihedral angle between the two benzene rings in the stilbene skeleton is 32.80 (8)°.

Synthesis and in vitro evaluation of N-alkyl-3-hydroxy-3-(2-imino-3-methyl-5-oxoimidazolidin-4-yl)indolin-2-one analogs as potential anticancer agents.

A series of novel 3-hydroxy-3-(2-imino-3-methyl-5-oxoimidazolidin-4-yl)indolin-2-one analogs (3) have been synthesized under microwave irradiation and conventional heating methods. These analogs were evaluated for in vitro cytotoxicity against a panel of 57 human tumor cell lines. Compound 3o had GI(50) values of 190 nM and 750 nM against A549/ATTC non-small cell lung cancer and LOX IMVI melanoma cell lines, respectively, and both 3n and 3o exhibited GI(50) values ranging from 2 to 5 microM against CCRF-CEM, HL-60(TB), K-562, MOLT-4, and RPMI-8226 leukemia cell lines. These results indicate that N-4-methoxybenzyl-3-hydroxy-(2-imino-3-methyl-5-oxo-4-yl)indolin-2-one analogs may be useful leads for anticancer drug development.

(Z)-2-Amino-5-[2,4-dimeth-oxy-6-(4-methoxy-styr-yl)benzyl-idene]-1,3-thia-zol-4(5H)-one methanol solvate.

In the crystal structure of the title compound, C(21)H(20)N(2)O(4)S·CH(3)OH, mol-ecules are linked into chains by a series of inter-molecular N-H⋯O, N-H⋯N and O-H⋯O hydrogen bonds. The mol-ecular structure shows a double bond with Z geometry, connecting the thia-zolone and resveratrol units. The dihedral angle between the thiazolone ring and the nearest dimethoxy-benzene ring is 53.02 (7)°.

Studies on Dibenzylamines as Inhibitors of Venezuelan Equine Encephalitis Virus.

Alphaviruses are arthropod-transmitted members of the Togaviridae family that can cause severe disease in humans, including debilitating arthralgia and severe neurological complications. Currently, there are no approved vaccines or antiviral therapies directed against the alphaviruses, and care is limited to treating disease symptoms. A phenotypic cell-based high-throughput screen was performed to identify small molecules that inhibit the replication of Venezuelan Equine Encephalitis Virus (VEEV). The compound, 1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-N-(3-fluoro-4-methoxybenzyl)ethan-1-amine (1), was identified as a highly active, potent inhibitor of VEEV with an effective concentration for 90% inhibition of virus (EC90) of 0.89 µM and 7.49 log reduction in virus titers at 10 µM concentration. These data suggest that further investigation of compound 1 as an antiviral therapeutic against VEEV, and perhaps other alphaviruses, is warranted. Experiments suggested that the antiviral activity of compound 1 is directed at an early step in the VEEV replication cycle by blocking viral RNA and protein synthesis.

Synthesis and Evaluation of 2-Naphthaleno trans-Stilbenes and Cyanostilbenes as Anticancer Agents.

BACKGROUND: Naphthalene is a good structural replacement for the isovanillin moiety (i.e. the 3- hydroxy-4-methoxyphenyl unit) in the combretastatin A-4 molecule, a natural product structurally related to resveratrol, which consistently led to the generation of highly cytotoxic naphthalene analogues when combined with a 3,4,5-trimethoxyphenyl or related aromatic system. Also, the naphthalene ring system is present in many current drug molecules that are utilized for anti-tumor, anti-arrhythmia and antioxidant therapy. OBJECTIVE: In our continuing quest to improve the potencies of naturally occurring anti-cancer molecules through chemical modification, we have now synthesized a small library of 2-naphthaleno trans- stilbenes and cyanostilbenes that are structurally related to both resveratrol and DMU-212, and have evaluated these novel analogs against a panel of 54 human tumor cell lines. METHOD: A series of 2-naphthaleno-containing trans-stilbenes 3a-3h (Scheme 1) were synthesized by Wittig reaction of a variety of aromatic substituted benzyl-triphenylphosphonium bromide reactants with 2- naphthaldehyde using n-BuLi as a base in THF. A second series of 2-naphthaleno trans-cyanostilbenes analogs 5a-5h was synthesized by reaction of 2-naphthaldehyde (2; 1 mmol) with an appropriately substituted 2- phenylacrylonitrile 4a-4h; 1 mmol) in 5% sodium methoxide/methanol. The reaction mixture was stirred at room temperature for 2-3 hours and the reaction allowed to go to completion (TLC monitoring), during which time the desired product precipitated out of the solution as a solid. The resulting precipitate was filtered off, washed with water and dried to yield the desired compound in yields ranging from 70-95% (Scheme 2). RESULTS: The percentage growth inhibition of 54 human cancer cell lines in a primary NCI screen after exposure to compounds 3a, 3d, 5b and 5c was carried out. The results showed that only compounds 5b and 5c met the criteria for subsequent testing to determine growth inhibition values (GI50) in dose-response studies. At 10-5 M concentration, compounds 5b and 5c exhibited cytotoxic activity against leukemia cell lines HL-60(TB) and SR, lung cancer cell line NCI-H522, colon cancer cell lines COLO 205 and HCT-116, CNS-cancer cell line SF-539, melanoma cell line MDA-MB-435, and breast cancer cell line BT-549. The naphthalene trans-stilbene analogue 3a, exhibited significant growth inhibition against only one cell line, melanoma cell line MDA-MB-435 (96 % growth inhibition). Compound 3d was inactive in the 10-5 M single dose screen. CONCLUSION: We have synthesized a small set of novel 2-naphthaleno stilbenes and cyanostilbenes and evaluated several of these compounds for their anticancer properties against a panel of 54 human tumor cell lines. The most active analogs, 5b and 5c, showed significantly improved growth inhibition against the human cancer cells in the NCI panel when compared to DMU-212. Of these compounds, analog 5c was found to be the most potent anticancer agent and exhibited significant growth inhibitory effects against COLO 205, CNS SF 539 and melanoma SK-MEL 5 and MDA-MB-435 cell lines with GI50 values ≤ 25 nM. Analog 5b also exhibited GI50 values in the range 25-41 nM against CNS SF 295 and melanoma MDA-MB-435 and UACC-62 cell lines. Compounds 5b and 5c were also cytotoxic towards the MV4-11 leukemia cell line with LD50 value of 450 nM and 200 nM, respectively, and demonstrated >50% inhibition of tubulin polymerization at concentrations below their LD50 values in these cells. In silico docking studies suggest that compounds 5b and 5c bind favorably at the colchicine- binding pocket of the tubulin dimer, indicating that both 5b and 5c may inhibit tubulin polymerization through a mechanism similar to that exhibited by colchicine. Derivative 5c demonstrated more favorable binding based on the docking score and buried surface area, as compared to compound 5b, in agreement with the higher observed potency of 5c against a broader range of tumor cell lines. Based on these results, analog 5c is considered to be a lead compound for further optimization as a clinical candidate for treating a variety of cancers.

Synthesis and anti-cancer screening of novel heterocyclic-(2H)-1,2,3-triazoles as potential anti-cancer agents.

trans-Cyanocombretastatin A-4 (trans-CA-4) analogues have been structurally modified to afford their more stable CA-4-(2H)-1,2,3-triazole analogues. Fifteen novel, stable 4-heteroaryl-5-aryl-(2H)-1,2,3-triazole CA-4 analogues (8a-i, 9 and 11a-e) were evaluated for anti-cancer activity against a panel of 60 human cancer cell lines. These analogues displayed potent cytotoxic activity against both hematological and solid tumor cell lines with GI50 values in the low nanomolar range. The most potent compound, 8a, was a benzothiophen-2-yl analogue that incorporated a 3,4,5-trimethoxyphenyl moiety connected to the (2H)-1,2,3-triazole ring system. Compound 8a exhibited GI50 values of <10 nM against 80% of the cancer cell lines in the panel. Three triazole analogues, 8a, 8b and 8g, showed particularly potent growth inhibition against the triple negative Hs578T breast cancer cell line with GI50 values of 10.3 nM, 66.5 nM and 20.3 nM, respectively. Molecular docking studies suggest that these compounds bind to the same hydrophobic pocket at the interface of α- and ß-tubulin that is occupied by colchicine and cis-CA-4, and are stabilized by Van der Waals' interactions with surrounding amino acid residues. Compound 8a was found to inhibit tubulin polymerization in vitro with an IC50 value of 1.7 µM. The potent cytotoxicity of these novel compounds and their inhibition of tubulin dynamics make these triazole analogues promising candidates for development as anti-cancer drugs.

Synthesis and biological evaluation of novel 4,5-disubstituted 2H-1,2,3-triazoles as cis-constrained analogues of combretastatin A-4.

A series of combretastatin A-4 (CA-4) analogues have been prepared from (Z)-substituted diarylacrylonitriles (1a-1p) obtained in a two-step synthesis from appropriate arylaldehydes and acrylonitriles. The resulting 4,5-disubstituted 2H-1,2,3-triazoles were evaluated for their anti-cancer activities against a panel of 60 human cancer cell lines. The diarylacrylonitrile analogue 2l exhibited the most potent anti-cancer activity in the screening studies, with GI50 values of <10 nM against almost all the cell lines in the human cancer cell panel and TGI values of <10 nM against cancer cell lines SF-539, MDA-MB-435, OVCAR-3 and A498. Furthermore, in silico docking studies of compounds 2l, 2e and 2h within the active site of tubulin were carried out in order to rationalize the mechanism of the anti-cancer properties of these compounds. From the in silico studies, compound 2e was predicted to have better affinity for the colchicine binding site on tubulin compared to compounds 2l and 2h. Analogue 2e was also evaluated for its anti-cancer activity by colony formation assay against 9LSF rat gliosarcoma cells and afforded an LD50 of 7.5 nM. A cell cycle redistribution assay using analogue 2e was conducted to further understand the mechanism of action of these CA-4 analogues. From this study, analogues 2e and 2l were the most potent anti-cancer agents in this structural class, and were considered lead compounds for further development as anti-cancer drugs.

Synthesis, anticancer activity and molecular docking studies on a series of heterocyclic trans-cyanocombretastatin analogues as antitubulin agents.

A series of heterocyclic combretastatin analogues have been synthesized and evaluated for their anticancer activity against a panel of 60 human cancer cell lines. The most potent compounds were two 3,4,5-trimethoxy phenyl analogues containing either an (Z)-indol-2-yl (8) or (Z)-benzo[b]furan-2-yl (12) moiety; these compounds exhibited GI50 values of <10 nM against 74% and 70%, respectively, of the human cancer cell lines in the 60-cell panel. Compounds 8, and 12 and two previously reported compounds in the same structural class, i.e. 29 and 31, also showed potent anti-leukemic activity against leukemia MV4-11 cell lines with LD50 values = 44 nM, 47 nM, 18 nM, and 180 nM, respectively. From the NCI anti-cancer screening results and the data from the in vitro toxicity screening on cultured AML cells, seven compounds: 8, 12, 21, 23, 25, 29 and 31 were screened for their in vitro inhibitory activity on tubulin polymerization in MV4-11 AML cells; at 50 nM, 8 and 29 inhibited polymerization of tubulin by >50%. The binding modes of the three most active compounds (8, 12 and 29) to tubulin were also investigated utilizing molecular docking studies. All three molecules were observed to bind in the same hydrophobic pocket at the interface of α- and ß-tubulin that is occupied by colchicine, and were stabilized by van der Waals' interactions with surrounding tubulin residues. The results from the tubulin polymerization and molecular docking studies indicate that compounds 8 and 29 are the most potent anti-leukemic compounds in this structural class, and are considered lead compounds for further development as anti-leukemic drugs.

Synthesis and evaluation of a series of resveratrol analogues as potent anti-cancer agents that target tubulin.

A series of novel diarylacrylonitrile and trans-stilbene analogues of resveratrol has been synthesized and evaluated for their anticancer activities against a panel of 60 human cancer cell lines. The diarylacrylonitrile analogues 3b and 4a exhibited the most potent anticancer activity of all the analogues synthesized in this study, with GI50 values of < 10 nM against almost all the cell lines in the human cancer cell panel. Compounds 3b and 4a were also screened against the acute myeloid leukemia (AML) cell line, MV4-11, and were found to have potent cytotoxic properties that are likely mediated through inhibition of tubulin polymerization. Results from molecular docking studies indicate a common binding site for 4a and 3b on the 3,3-tubulin heterodimer, with a slightly more favorable binding for 3b compared to 4a; this is consistent with the results from the microtubule assays, which demonstrate that 4a is more potent than 3b in inhibiting tubulin polymerization in MV4-11 cells. Taken together, these data suggest that diarylacrylonitriles 3b and 4a may have potential as antitubulin therapeutics for treatment of both solid and hematological tumors.