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

Synthesis of novel piperazine-based bis(thiazole)(1,3,4-thiadiazole) hybrids as anti-cancer agents through caspase-dependent apoptosis

A series of novel piperazine-based bis(thiazoles) 13a-d were synthesized in moderate to good yields via reaction of the bis(thiosemicarbazones) 7a, b with an assortment of C-acetyl-N-aryl-hydrazonoyl chlorides 8a-f. Similar treatment of the bis(thiosemicarbazone) 7a, b with C-aryl-N-phenylhydrazonoyl chlorides 10a, b afforded the expected bis(thiadiazole) based piperazine products 13b-d in reasonable yields. Cyclization of 7a, b with two equivalents of α-haloketones 14a-d led to the production of the corresponding bis(4-arylthiazol)piperazine derivatives 15a-h in good yields. The structures of the synthesized compounds were confirmed from elemental and spectral data (FTIR, MALDI-TOF, 1H, and 13C NMR). The cytotoxicity of the new compounds was screened against hepatoblastoma (HepG2), human colorectal carcinoma (HCT 116), breast cancer (MCF-7), and Human Dermal Fibroblasts (HDF). Interestingly, all compounds showed promising cytotoxicity against most of the cell lines. Interestingly, compounds 7b, 9a, and 9i exhibited IC50 values of 3.5, 12.1, and 1.2 nM, respectively, causing inhibition of 89.7%, 83.7%, and 97.5%, compared to Erlotinib (IC50 = 1.3 nM, 97.8% inhibition). Compound 9i dramatically induced apoptotic cell death by 4.16-fold and necrosis cell death by 4.79-fold. Compound 9i upregulated the apoptosis-related genes and downregulated the Bcl-2 as an anti-apoptotic gene. Accordingly, the most promising EGFR-targeted chemotherapeutic agent to treat colon cancer was found to be compound 9i.

Tunable pH-Responsive Polymeric Micelle for Cancer Treatment

The development of bioresponsive polymers is important in drug delivery systems. Herein, we reported the construction of a series of pH-sensitive micelles by conjugating the hydrophilic polyethylene glycol (PEG) segment to a hydrophobic farnesylthiosalicylate derivative, FTS-hydrazide (FTS-H), with a hydrazone linker, whose cleavability can be conveniently modulated by choosing various lengths of the carbon chain or appropriate electron-withdrawing groups with different steric environment around the hydrazone linker. We examined the hydrolysis rates of these pH-sensitive micelles in both neutral and acidic conditions. One of the pH-sensitive micelles (PHF-2) was found to be highly sensitive to acidic conditions while being fairly stable in neutral conditions. Furthermore, PHF-2 micelles well retained the antitumor activity of free FTS-H. We further evaluated the use of PHF-2 micelles as a carrier for delivering paclitaxel (PTX) and the triggered release of PTX under the acidic environment. PTX-loaded PHF-2 micelles showed enhanced antitumor activity compared with free PTX, likely because of the combinational effect between PHF-2 micelles and loaded PTX.

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 (5a–r) 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.

Hybrids from Farnesylthiosalicylic Acid and Hydroxamic Acid as Dual Ras-Related Signaling and Histone Deacetylase (HDAC) Inhibitors: Design, Synthesis and Biological Evaluation

A novel series of hybrids was designed and synthesized by combining key elements from farnesylthiosalicylic acid (FTS) and hydroxamic acid. Several 3,7,11-trimethyldodeca-2,6,10-trien-1-yl) thio)benzamide derivatives, particularly those with branched and linear aliphatic linkers between the hydroxamic zinc binding group (ZBG) and the benzamide core, not only displayed significant antitumor activities against six human cancer cells but also exhibited histone deacetylase (HDAC) inhibitory effects in vitro. Among them, N-(4-(hydroxyamino)-4-oxobutyl)-2-(((2E,6E)-3,7,11-trimethyldodeca-2,6, 10-trien-1-yl)thio)benzamide (8 d) was the most potent, with IC50 values of 4.9-7.6 μM; these activities are eight- to sixteen-fold more potent than FTS and comparable to that of suberoylanilide hydroxamic acid (SAHA). Derivative 8 d induced cell cycle arrest in the G0/G1 phase, inhibited the acetylation of histone H3 and α-tubulin, and blocked Ras-related signaling pathways in a dose-dependent manner. The improved tumor growth inhibition and cell-cycle arrest in vitro might result from the dual inhibition. These findings suggest dual inhibitors of Ras-related signaling pathway and HDAC hold promise as therapeutic agents for the treatment of cancer.

Synthesis and biological evaluation of novel derivatives of gambogenic acid as anticancer agents

A series of novel derivatives of gambogenic acid (GNA) were synthesized and evaluated for their in vitro antiproliferative activity against four kinds of tumor cell lines. These compounds displayed potent antiproliferative activity. In particular, compound 3f exhibited superior antiproliferative activity against these tumor cell lines than GNA.

Hybrid molecule from Farnesylthiosalicylic acid-diamine and phenylpropenoic acid as Ras-related signaling inhibitor with potent antitumor activities

Novel series of Farnesylthiosalicylic acid-diamine/phenylpropenoic acid hybrids were designed and synthesized. Their in vitro growth inhibitory assays showed that most compounds displayed strong antiproliferation activity against seven cancer cells. Especially, the new hybrid 12 f, by the conjugation of 10a with ferulic acid, could selectively suppress the proliferation of tumor cells and display significantly lower toxicities to normal cells than its intermediate 10a. Furthermore, 12 f dose-dependently induced SMMC-7721 cell apoptosis. Additionally, our observations demonstrated that 12 f inhibited both Ras-related signaling and phosphorylated NF-κB synergistically, which may be advantageous to the strong antitumor activities of 12 f. Our findings suggest that these novel hybrids may hold a great promise as therapeutic agents for the intervention of human cancers.