A prodrug micellar carrier assembled from polymers with pendant farnesyl thiosalicylic acid moieties for improved delivery of paclitaxel.

UNLABELLED: In order to achieve enhanced and synergistic delivery of paclitaxel (PTX), a hydrophobic anticancer agent, two novel prodrug copolymers, POEG15-b-PFTS6 and POEG15-b-PFTS16 composed of hydrophilic poly(oligo(ethylene glycol) methacrylate) (POEG) and hydrophobic farnesylthiosalicylate (FTS, a nontoxic Ras antagonist) blocks, were synthesized. Both POEG-b-PFTS polymers were able to form micelles with intrinsic antitumor activity in vitro and in vivo. Employing these micelles as a carrier to load PTX, their drug loading capacity, stability, in vivo biodistribution and tumor inhibition effect were evaluated. PTX/POEG15-b-PFTS16 mixed micelles exhibited an excellent stability of 9days at 4°C with a PTX loading capacity of 8.2%, which was more effective than PTX/POEG15-b-PFTS6 mixed micelles. In vivo biodistribution data showed that DiR-loaded POEG-b-PFTS micelles were more effectively localized in the tumor than in other organs. Moreover, both PTX/POEG-b-PFTS micelles showed significantly higher antitumor activity than Taxol in a 4T1.2 murine breast tumor model, and the tumor inhibition and animal survival followed the order of PTX/POEG15-b-PFTS16>PTX/POEG15-b-PFTS6>POEG15-b-PFTS16>Taxol≈POEG15-b-PFTS6. Our data suggest that POEG-b-PFTS micelles are a promising anticancer drug carrier that warrants more studies in the future. STATEMENT OF SIGNIFICANCE: Polymerization of drug-based monomer represents a facile and precise method to obtain well-defined polymeric prodrug amphiphiles. Currently, most reports largely focus on the synthesis methods and the biophysical properties. There is limited information about their anti-tumor activity and delivery function as prodrug carriers in vitro and in vivo. In this manuscript, we report the development of two novel prodrug copolymers, POEG15-b-PFTS6 and POEG15-b-PFTS16 composed of hydrophilic poly(oligo(ethylene glycol) methacrylate) (POEG) and hydrophobic farnesylthiosalicylate (FTS, a nontoxic Ras antagonist) blocks. Both POEG-b-PFTS polymers were able to self-assemble into nano-sized micelles with intrinsic antitumor activity in vitro and in vivo. More importantly, POEG-b-PFTS polymers were effective in forming stable mixed micelles with various anticancer agents including PTX, DOX, docetaxel, gefitinib, and imatinib. Delivery of PTX via our new carrier led to significantly improved antitumor activity, suggesting effective PTX/FTS combination therapy. We believe that our study shall be of broad interest to the readers in the fields of biomaterials and drug delivery.

Novel FTS-diamine/cinnamic acid hybrids inhibit tumor cell proliferation and migration and promote apoptosis via blocking Ras-related signaling in vitro.

Novel FTS-diamine/cinnamic acid hybrids 7a-f were prepared, and their in vitro biological activities were evaluated. It was found that 7c showed the strongest anti-proliferation activities against cancer cells in vitro and significant growth inhibition of tumor in vivo, and more potential for inhibitory selectivity to tumor cells than intermediate 6 and FTS. Furthermore, the anti-proliferative effect of 7c in Lovo cell lines followed a similar pattern, which included a dose-dependent induction of cell apoptosis via the up-regulation of Bax as well as activated caspase-3 and down-regulation of Bcl-2, and the inhibition of cancer cells migration and invasion in a concentration-dependent way. More importantly, 7c could significantly block Ras-related signaling pathways, which may contribute to its pro-apoptotic induction of the cancer cell lines and its inhibition of carcinoma cell proliferation, migration, and invasion. Therefore, our novel findings may provide a new framework for the discovery of new FTS hybrids for the intervention of human carcinoma cells.

Synthesis and biological evaluation of hybrids from farnesylthiosalicylic acid and hydroxylcinnamic acid with dual inhibitory activities of Ras-related signaling and phosphorylated NF-κB.

A series of hybrids (5a­r) of farnesylthiosalicylic acid (FTS) and hydroxylcinnamic acid were designed and synthesized. Most of the hybrids displayed potent antiproliferative activity against seven cancer cell lines in vitro, superior to FTS as well as sorafenib. The most potent compound 5f selectively inhibited cancer cells but not non-tumor liver cell proliferation in vitro, and significantly induced SMMC-7721 cell apoptosis. Interestingly, 5f could simultaneously inhibit not only Ras-related signaling but also phosphorylated NF-κB, which may synergetically contribute to the cell growth inhibition and apoptosis induction. Moreover, 5f showed low acute toxicity to mice and significantly inhibited the hepatoma tumor growth.

Synthesis and antibacterial evaluation of 3-Farnesyl-2-hydroxybenzoic acid from Piper multiplinervium.

3-Farnesyl-2-hydroxybenzoic acid is an antibacterial agent isolated from the leaves of Piper multiplinervium. This compound has activity against both Gram positive and Gram negative bacteria including Escherichia coli, Staphylococcus aureus and Helicobacter pylori. This research aimed to synthesize a natural antibacterial compound and its analogs. The synthesis of 3-Farnesyl-2-hydroxybenzoic acid consists of three steps: straightforward synthesis involving protection of phenolic hydroxyl group, coupling of suitable isoprenyl chain to the protected aromatic ring at ortho position followed by carboxylation with concomitant deprotection to give the derivatives of the salicylic acid. All the three prenylated compounds synthesized were found to exhibit spectrum of activity against S. aureus (ATCC) having MIC: 5.84×10(-3), 41.46×10(-2) and 6.19×10(-1) µmol/ml respectively. The compounds also displayed activity against resistance strain of S. aureus (SA1119B) having MIC: 5.84×10(-3), 7.29×10(-3) and 3.09×10(-1) µmol/ml respectively. This synthesis has been achieved and accomplished with the confirmation of it structure to that of the original natural product, thus producing the first synthesis of the natural product and providing the first synthesis of its analogs with 3-Farnesyl-2-hydroxybenzoic acid having biological activity higher than that of the original natural product.

Synthesis and biological evaluation of novel farnesylthiosalicylic acid derivatives for cancer treatment.

Novel farnesylthiosalicylic acid (FTS) derivatives were synthesized by coupling with different substituted diamines. Their in vitro growth inhibitory activities against seven human cancer cell lines were evaluated. The results revealed that the synthetic farnesylthiosalicylamides displayed significant antitumor activities compared to the positive control FTS. Especially, compound 8f exhibited the strongest antitumor activities with IC50 values of 6.20-7.83 µM, which were one- to threefold less than those of sorafenib and six- to tenfold less than that of FTS against each cell line in vitro. Furthermore, 8f could inhibit the Ras-related signaling pathway and induce SMMC-7721 cell apoptosis superior to FTS in a dose-dependent manner. These data indicate that 8f may hold greater promise as therapeutic agent for the intervention of human cancers.

Synthesis and biological evaluation of farnesylthiosalicylamides as potential anti-tumor agents.

Fourteen hybrids of farnesylthiosalicylic acid (FTS) with various diamines were synthesized and biologically evaluated. It was found that FTS-monoamide molecules (10a-g) displayed strong anti-proliferative activity against seven human cancer cell lines, superior to FTS and FTS-bisamide compounds (11a-g). The mono-amide 10f was the most active, with IC50s of 3.78-7.63 µM against all tested cancer cells, even more potent than sorafenib (9.12-22.9 µM). In addition, 10f induced SMMC-7721 cell apoptosis, down-regulated the expression of Bcl-2 and up-regulated Bax and caspase-3. Furthermore, 10f had the improved aqueous solubility relative to FTS. Finally, treatment with 10f dose-dependently inhibited the Ras-related signaling pathways in SMMC-7721 cells. Collectively, 10f could be a promising candidate for the intervention of human cancers.

A convergent stereocontrolled total synthesis of (-)-terpestacin.

A stereocontrolled total synthesis of (-)-terpestacin has been achieved starting from (R)-(-)-carvone as a chiral pool and (E,E)-farnesol via a highly convergent approach. Thus, (R)-(-)-carvone was transformed into the cyclopentanone segment through a series of high yielding operations with the proper setup of all the stereochemical centers while (E,E)-farnesol was converted into the other requisite building block via a series of high yielding reactions. The cyclopentanone intermediate was both selectively enolized and alkylated at room temperature to yield the desired coupling product, which provided the natural product upon further transformations.

Novel nitric oxide-releasing derivatives of farnesylthiosalicylic acid: synthesis and evaluation of antihepatocellular carcinoma activity.

Novel furoxan-based nitric oxide (NO) releasing derivatives (8a-p) of farnesylthiosalicylic acid (FTS) were synthesized. Compound 8l displayed the strongest inhibition on the proliferation of human hepatocellular carcinoma (HCC) cells in vitro, superior to FTS, sorafenib, and furoxan moiety, selectively induced high frequency of HCC cell apoptosis, and produced high levels of NO in HCC cells but not in nontumor liver cells. Furthermore, 8l exhibited low acute toxicity to mice and significantly inhibited the growth of HCC tumors in vivo and the Ras-related signaling in the tumors. Therefore, our novel findings may provide a new framework for the design of new NO-releasing furoxan/FTS hybrids for the intervention of human HCC.

Enzymatic synthesis of farnesyl laurate in organic solvent: initial water activity, kinetics mechanism, optimization of continuous operation using packed bed reactor and mass transfer studies.

The influence of water activity and water content was investigated with farnesyl laurate synthesis catalyzed by Lipozyme RM IM. Lipozyme RM IM activity depended strongly on initial water activity value. The best results were achieved for a reaction medium with an initial water activity of 0.11 since it gives the best conversion value of 96.80%. The rate constants obtained in the kinetics study using Ping-Pong-Bi-Bi and Ordered-Bi-Bi mechanisms with dead-end complex inhibition of lauric acid were compared. The corresponding parameters were found to obey the Ordered-Bi-Bi mechanism with dead-end complex inhibition of lauric acid. Kinetic parameters were calculated based on this model as follows: V (max) = 5.80 mmol l(-1) min(-1) g enzyme(-1), K (m,A) = 0.70 mmol l(-1) g enzyme(-1), K (m,B) = 115.48 mmol l(-1) g enzyme(-1), K (i) = 11.25 mmol l(-1) g enzyme(-1). The optimum conditions for the esterification of farnesol with lauric acid in a continuous packed bed reactor were found as the following: 18.18 cm packed bed height and 0.9 ml/min substrate flow rate. The optimum molar conversion of lauric acid to farnesyl laurate was 98.07 ± 0.82%. The effect of mass transfer in the packed bed reactor has also been studied using two models for cases of reaction limited and mass transfer limited. A very good agreement between the mass transfer limited model and the experimental data obtained indicating that the esterification in a packed bed reactor was mass transfer limited.

New derivatives of farnesylthiosalicylic acid (salirasib) for cancer treatment: farnesylthiosalicylamide inhibits tumor growth in nude mice models.

The Ras inhibitor S-trans,trans-farnesylthiosalicylic acid (FTS, Salirasib) interferes with Ras membrane interactions that are crucial for Ras-dependent transformation. It remains unknown whether modifications of the carboxyl group of FTS can affect its activity. Here we show that specific modifications of the FTS carboxyl group by esterification or amidation yield compounds with improved growth inhibitory activity, compared to FTS, as shown in Panc-1 and U87 cells. The most potent compounds were FTS-methoxymethyl ester and FTS-amide. However, selectivity toward active Ras-GTP, as known for FTS, was apparent with the amide derivatives of FTS. FTS-amide exhibited the overall highest efficacy in inhibition of Ras-GTP and cell growth. This new compound significantly inhibited growth of both Panc-1 tumors and U87 brain tumors. Thus amide derivatives of the FTS carboxyl group provide potent cell-growth inhibitors without loss of selectivity toward the active Ras protein and may serve as new candidates in cancer therapy.

Synthesis of farnesol isomers via a modified Wittig procedure.

[structure: see text] The four olefin stereoisomers of farnesol have been synthesized from readily available nerylacetone or commercial geranylacetone. A new variation on the use of beta-oxido ylides favored the (2Z)-stereoisomers, whereas the (2E)-isomers were obtained through a classical Horner-Wadsworth-Emmons condensation with triethyl phosphonoacetate and reduction of the resulting ester.

Biologically active fluorescent farnesol analogs.

We describe ten polyene analogs of farnesol, typified by 3,7,11-trimethyl-2,4,6,8,10-dodecapentenaldehyde oxime, which preserve the length, cross-section, and approximate hydrophobicity of farnesol. Four of the ten display strong quorum-sensing activity in the human pathogen Candida albicans, with IC(50) values for inhibition of germ-tube formation as low as 10 microM. The polyenes display absorption maxima between 320 and 380 nm, with the extinction coefficients for the oximes approaching 100,000. All but two of the analogs are fluorescent, with excitation maxima varying over the range of 320-370 nm. Oxime anti-4, which can undergo fluorescence excitation at wavelengths beyond 400 nm, is demonstrated to be useful for confocal fluorescence microscopic imaging of fungal cells. The farnesol analogs are also expected to be useful for detection of farnesol binding proteins and in determination of farnesol pharmacokinetics.

African elephant sesquiterpenes. II. Identification and synthesis of new derivatives of 2,3-dihydrofarnesol.

A search for potential semiochemicals revealed nerolidol (6), albicanol (7), and the new 2,3-dihydrofarnesol derivatives 8-10 in the temporal gland secretions of African elephants. A novel synthesis from (E,E)-farnesol (1) provided compounds 8-10 for GC-MS comparison to the natural products. This study confirms the farnesol family as frequently occurring secondary metabolites in African elephant temporal gland secretions.

A general stereocontrolled, convergent synthesis of oligoprenols that parallels the biosynthetic pathway.

A solution is reported to the classic unsolved problem of stereoselective synthesis of all-E oligoprenols, such as E-farnesylfarnesol, by a cationic coupling analogous to the biosynthetic pathway. The simplicity and efficacy of the method, which is outlined in Scheme 1, are demonstrated by the synthesis of a series of all-E oligoprenols from C(20) to C(35) in uniformly excellent overall yield. The success of the approach is due not only to the highly E-stereoselective C-C coupling that forms the oligoprenyl chain but also to the development of efficient syntheses of allylic secondary silanes and E-oligoprenal acetals, and to a selective allylic demethoxylation reaction.

Inhibition effect of new farnesol derivatives on all-trans-retinoic acid metabolism.

All-trans-retinoic acid (atRA) is a promising anticancer and antiwrinkle drug. However, its clinical application is limited because it is rapidly metabolized by the induced cytochrome P450 (P450). In this study, farnesol derivatives are proposed as new inhibitors to prevent P450-mediated metabolism. The farnesol derivatives were suc-farnesol and mal-farnesol, which were synthesized by the chemical conjugation of farnesol with succinic anhydride and maleic anhydride, respectively. The inhibition effects of farnesol, farnesoic acid, and farnesol derivatives on the atRA metabolism were evaluated in microsome and in AMC-HN-6 cells. In the microsome experiment, suc-farnesol and mal-farnesol strongly inhibited atRA metabolism at 10(minus;4) mol/L concentration by as much as 61% and 77%, respectively. In the cell experiment, the inhibition effects of farnesol derivatives on the atRA metabolism showed similar tendency as the results in the microsome experiment, even if the effect was somewhat decreased. Effects of farnesoic acid and farnesol, however, were not significant. This research suggests that carboxylic end groups, such as atRA and hydrophobicity, might be important factors causing the higher inhibition effect, and that derivatization of farnesol can be 1 method to develop new inhibitors of atRA metabolism.

Chemical synthesis and 2H NMR investigations of polyisoprenols: dynamics in model membranes.

Polyisoprenols (PIs) such as dolichol and undecaprenol have been shown to play an important role as enzymatic cofactors in the synthesis of glycoconjugates of both prokaryotic and eukaryotic cells. Presented here is a synthetic route used for obtaining specifically labeled [omega,omega-(C2H3)2]PIs that initiates with the selective oxidation of the omega-terminal double bond of the PI with N-bromosuccinimide. Continuation of the reaction sequence produces an omega-terminal aldehyde three carbons shorter than the original PI. A Wittig reaction with an appropriate deuterium-labeled phosphonium salt is then used to form an omega-terminal-deuterated PI identical with the starting material except for replacement of 1H with 2H at the two omega-terminal methyls of the PI. Deuterium NMR spectra of [omega, omega-(C2H3)2]geraniol and -farnesol incorporated into phospholipid multilamellar vesicles show powder patterns. The quadrupole splitting of the 2H NMR signals was interpretable in terms of the degree of orderedness of the 2H-labeled site. The pure trans isomer geraniol gave rise to a single set of splittings for each C2H3 group while farnesol, a mixture of isomers, showed multiple quadrupole splittings. The quadrupole splittings of the PIs increased with increasing concentration of label and with lowering of temperature. Deuterium NMR T1 measurements, revealing rates of motion of the 2H-labeled site, showed fast motion for [omega,omega-(C2H3)3]geraniol relative to [omega,omega-(C2H3)2]cholesterol under similar conditions. A correlation time of 5 X 10(-10) s was estimated for [omega,omega-(C2H3)2]geraniol, which was 1 order of magnitude faster than for [26,27-(C2H3)2]cholesterol.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of squalene synthetase by farnesyl pyrophosphate analogues.

The pyrophosphates of the following farnesol analogues have been synthesized: 2-methylfarnesol; 7,11-dimethyl-3-ethyl-2,6,10-dodecatrien-1-ol; 3-demethylfarnesol; 4-methylthiofarnesol; 7,11-dimethyl-3-iodo-2,6,10-dodecatrien-1-ol; 7,11-dimethyl02-iodo-2,6,10-dodecatrien-1-ol; 7,11-dimethyldodeca-6,10-dien-2-yn-1-ol; phytol; 3,7,11-trimethyl-2-dodecen-1-ol; 3,7,11-trimethyldodecan-1-ol; and geraniol. The double bonds in all the above compounds were in the E configuration, except phytol, which was a 7:3 mixture of 2E and 2Z isomers. Each of the pyrophosphates inhibits the incorporation of labeled farnesyl pyrophosphate into squalene by a yeast enzyme preparation. Free alcohols and monophosphates are inactive. The analogues, listed in order of decreasing inhibitory strength, are, by kinetic analysis, competitive or mixed inhibitors. Irreversible inhibition is not observed. The results suggest that binding to the enzyme is primarily mediated by the pyrophosphate moiety assisted by relatively nonspecific lipophilic interactions. Decreasing the chain length and saturating double bonds severely reduces binding, while substitution at the 2,3, and 4 positions, and lengthening of the chain, is well tolerated.