Synthesis and anticancer activity of some 5-fluoro-2'-deoxyuridine phosphoramidates

Chemopreventive efficacy of stampidine in a murine breast cancer model

Background: The purpose of the present study was to examine the chemopreventive effect of stampidine, an aryl phosphate derivative of stavudine, in side by side comparison with the standard anti-breast cancer drug paclitaxel in the well-established 7,12-dimethylbenz(a)anthracene (DMBA)-induced murine breast cancer model.Methods: Groups of 20 female mice were challenged with the DMBA. DMBA-challenged mice were assigned to various chemoprevention treatments, including stampidine, paclitaxel, and stampidine plus paclitaxel according to the same treatment schedules for 25 weeks.Results: Stampidine resulted in substantially reduced numbers of tumors, tumor weight as well as tumor size in DMBA-treated mice. Stampidine was as effective as paclitaxel in the model and their combination exhibited greater chemopreventive activity, as measured by reduced tumor incidence and improved tumor-free survival as well as overall survival of DMBA-treated mice. The length of time for the initial tumor to appear in DMBA-challenged mice treated with stampidine was longer than that of mice treated DMBA-challenged control mice. Tumors from mice treated with stampidine or stampidine plus paclitaxel displayed unique changes of a signature protein cassette comprised BRCA1, p21, Bax, and Bcl-2.Conclusion: Stampidine has potent chemopreventive activity and is as effective as the standard chemotherapy drug paclitaxel in the chemical carcinogenesis.

Synthesis and in vitro anticancer activity of new gemcitabine-nucleoside analogue dimers containing methyltriazole or ester-methyltriazole linker

Two series of novel gemcitabine-nucleoside analogue dimers were synthesized using the 'click' chemistry approach. In the first series of dimers (21-30), the nucleoside units were connected with a stable methyltriazole 4N-3'(or 5')C linker whereas in the second series (31-40) with a cleavable ester-methyltriazole 4N-3'(or 5')C linker. Dimers 21-40 were evaluated for their cytotoxic activity in five human cancer cell lines such as cervical (HeLa), nasopharyngeal (KB), lung (A549), brain (U87), liver (HepG2) and normal dermal fibroblast cell line (HDF) using the sulforhodamine B (SRB) assay. Compound 29 comprising two gemcitabine (dFdC) units exhibited the highest activity among dimers 21-30. The activity of compound 29 was higher than that of dFdC in all the studied cancer cell lines. A similar order of activity was observed for compounds 25, 28, and 30. The best activity among all the dimers synthesized was displayed by compound 39, comprising two gemcitabine units with a cleavable linker. The activity of compound 39 was 5 to 9 times higher than that of dFdC, depending on the cell line. In addition, marked cytotoxic activity was shown by compounds 31, 36, 38, and 40.

Synthesis and anticancer activity of 3'-[4-fluoroaryl-(1,2,3-triazol-1-yl)]-3'-deoxythymidine analogs and their phosphoramidates

A series of novel 4-chlorophenyl N-alkyl phosphoramidates of 3'-[4-fluoroaryl-(1,2,3-triazol-1-yl)]-3'-deoxythymidines (20-49) was synthesized by means of phosphorylation of 3'-[4-aryl-(1,2,3-triazol-1-yl)]-3'-deoxythymidines (7-11) with 4-chlorophenyl phosphoroditriazolide (14), followed by a reaction with the appropriate amine. The synthesized compounds 7-11 and 20-49 were evaluated along with four known anticancer compounds for their cytotoxic activity in human cancer cell lines: cervical (HeLa), nasopharyngeal (KB), breast (MCF-7), osteosarcoma (143B) (only selected compounds 20, 24, 28, 32-36, 38, 40, 46) and normal human dermal fibroblast cell line (HDF) using the sulforhodamine B (SRB) assay. Among 3'-[4-aryl-(1,2,3-triazol-1-yl)]-3'-deoxythymidines (7-11) the highest activity in all the investigated cancer cells was displayed by 3'-[4-(3-fluorophenyl)-(1,2,3-triazol-1-yl)]-3'-deoxythymidine (9) (IC₅₀ in the range of 2.58-3.61 μM) and its activity was higher than that of cytarabine. Among phosphoramidates 20-49 the highest activity was demonstrated by N-n-propyl phosphoramidate of 3'-[4-(3-fluorophenyl)-(1,2,3-triazol-1-yl)]-3'-deoxythymidine (35) in all the cancer cells (IC₅₀ in the range of 0.97-1.94 μM). Also N-ethyl phosphoramidate of 3'-[4-(3-fluorophenyl)-(1,2,3-triazol-1-yl)]-3'-deoxythymidine (33) exhibited good activity in all the used cell lines (IC₅₀ in the range of 4.79-4.96 μM).

Cytotoxic and trypanocidal activities of cinchona alkaloid derivatives

A series of 27 cinchona alkaloid derivatives (1f-w, 2a-e and 3a-d) were investigated for their cytotoxic and trypanocidal activities using seven different cancer cell lines (KB, HeLa, MCF-7, A-549, Hep-G2, U-87 and HL-60), two normal cell lines (HDF and CHO) and bloodstream forms of Trypanosoma brucei brucei, respectively. Four compounds (1u, 1w, 2e and 3d) were identified with promising cytotoxic activity with 50% growth inhibition (GI₅₀ ) values below 10 μM. Two (2e and 3d) of the four compounds also exhibited potent anti-trypanosomal activity with GI₅₀ values of 0.3-0.4 μM. All four active compounds represented derivatives modified at their C-9 hydroxy group. With respect to anti-proliferative activity and selectivity, 2e (epi-N-quinidyl-N'-bis(3,5-trifluoromethyl)phenylthiourea) proved to be the most promising derivative for both cancer cells and bloodstream forms of T. b. brucei. The cytotoxic activity of compounds 1u, 1w, 2e and 3d was attributed to their ability to induce apoptosis in cancer cells. The results demonstrate the potential of cinchona alkaloid derivatives as novel anti-cancer and anti-trypanosome drug candidates.

Studies directed toward the asialoglycoprotein receptor mediated delivery of 5-fluoro-2'-deoxyuridine for hepatocellular carcinoma

The anticancer nucleoside 5-fluoro 2'-deoxyuridine-5'-phosphate (5-FdU-P) was attached via an amide chain linker to a triantennary GalNAc cluster as a means to deliver the drug to hepatic cells that recognize the amino sugar units.

New antiglioma zwitterionic pronucleotides with an FdUMP framework

We have designed and synthesized new 5-fluoro-2'-deoxyuridine 5'-phosphate pronucleotides which can function as potential agents against the glioblastoma multiforme tumor. Their anti-malignant potency has been tested against T98G, U-118 MG, U-87 MG gliomas, HeLa, and Caco-2 cancer cell lines, using MRC-5 healthy cells as a reference. Five of the sixteen compounds (4c, 4f-i) exhibited significant anticancer potency and high selectivity indices (SI 12-66). It is likely that these zwitterionic pronucleotides may function in a similar manner to zwitterionic phospholipids, by inducing cell membrane charge disorder, making the cell permeable to bioactive agents. The most promising therapeutic pronucleotides 4c, 4f-h, have high intestinal-blood uptake potency (Caco-2 cell line), and may be considered as potential, orally administrated, anticancer drugs.