John S. Cooperwood

A Review of Coumarin Derivatives in Pharmacotherapy of Breast Cancer

The coumarin (benzopyran-2-one, or chromen-2-one) ring system, present in natural products (such as the anticoagulant warfarin) that display interesting pharmacological properties, has intrigued chemists and medicinal chemists for decades to explore the natural coumarins or synthetic analogs for their applicability as drugs. Many molecules based on the coumarin ring system have been synthesized utilizing innovative synthetic techniques. The diversity oriented synthetic routes have led to interesting derivatives including the furanocoumarins, pyranocoumarins, and coumarin sulfamates (COUMATES), which have been found to be useful in photochemotherapy, antitumor and anti-HIV therapy, and as stimulants for central nervous system, antibacterials, anti-inflammatory, anti-coagulants, and dyes. Of particular interest in breast cancer chemotherapy, some coumarins and their active metabolite 7-hydroxycoumarin analogs have shown sulfatase and aromatase inhibitory activities. Coumarin based selective estrogen receptor modulators (SERMs) and coumarin-estrogen conjugates have also been described as potential antibreast cancer agents. Since breast cancer is the second leading cause of death in American women behind lung cancer, there is a strong impetus to identify potential new drug treatments for breast cancer. Therefore, the objective of this review is to focus on important coumarin analogs with antibreast cancer activities, highlight their mechanisms of action and structure-activity relationships on selected receptors in breast tissues, and the different methods that have been applied in the construction of these pharmacologically important coumarin analogs.

Prodrug and antedrug: Two diametrical approaches in designing safer drugs

The prodrug and antedrug concepts, which were developed to overcome the physical and pharmacological shortcomings of various therapeutic classes of agents, employ diametrically different metabolic transformations. The prodrug undergoes a predictable metabolic activation prior to exhibiting its pharmacological effects in a target tissue while the antedrug undergoes metabolic deactivation in the systemic circulation upon leaving a target tissue. An increased therapeutic index is the aspiration for both approaches in designing as well as evaluation criteria. The recent research endeavors of prodrugs include the gene-directed and antibodydirected enzymatic activation of a molecule in a targeted tissue, organ specific delivery, improved bioavailabilities of nucleosides and cellular penetration of nucleotides. As for antedrugs, emphasis in research has been based upon the design and synthesis of systemically inactive molecule by incorporating a metabolically labile functional group into an active molecule.

Synthesis and antiproliferative activity of coumarin-estrogen conjugates against breast cancer cell lines

The syntheses and cytotoxic activity of coumarin-estrogen conjugates are described. In vitro results indicated that conjugates 10, 11 and 13 show growth inhibitory activities at 5-dose concentration (100, 10, 1, 0.1, 0.01 muM) against the following NCI-7- human breast cancer cell lines: BT-549, HS 578T, MCF 7, MDA-MB-231/ATCC, MDA-MB-435, NCI/ADR-RES, and thus serve as new leads for further development of antibreast cancer agent.

In vitro Antiproliferative Activity of Benzopyranone Derivatives in Comparison with Standard Chemotherapeutic Drugs

The cytotoxic activities of five new benzopyranone derivatives containing basic amino side chain are described. Their cytotoxicities against ER(+) MCF‐7 and ER(–) MDA‐MB‐231 human breast cancer cell lines, and Ishikawa human endometrial cell line were determined after 72 h drug exposure employing CellTiter‐Glo assay at concentrations ranging from 0.01–1.0 × 105 nM. The antiproliferative activities of these compounds were compared to tamoxifen (TAM), 4‐hydroxytamoxifen (4‐OHT, active metabolite of tamoxifen), and raloxifene (RAL). In‐vitro results indicated that compounds 9, 10, 12, and 13 were more potent than TAM against the human breast cancer cell lines with IC50 < 20 µM. The in‐silico structure–activity relationships of these compounds and their binding mode within the estrogen receptor (ER) binding site using AutoDock vina are discussed.

Synthesis and Biological Activity of 3-N-Substituted Estrogen Derivatives as Breast Cancer Agents

3-N-substituted-estrogen derivatives were synthesized and characterized. Their antiproliferative activities against human ER (+) MCF-7 (Breast), ER (-) MDA-MB-231 (breast) and Ishikawa (endometrial) cancer cell lines were determined after 72 hours drug exposure employing CellTiter-Glo assay at concentrations ranging from (0.01-100,000 nM). The antiproliferative activities of these compounds were compared to tamoxifen (TAM), 4-hydroxytamoxifen (4-OHT, active metabolite of tamoxifen) and raloxifene (RAL). In vitro results indicated that compound 5 (IC50 = 12 µM) displayed comparable antiproliferative activity against MDA-MB 231 cell line; while compounds 6, 7 and 13 (IC50 = 12 µM) displayed higher activity against MCF-7 and Ishikawa cell lines, in comparison to TAM activity (19-33 µM).

Abstract 3238: Synthesis and evaluation of 17-oximino-estrone derivatives as potential anti-breast cancer agents

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL The selective estrogen receptor modulator (SERM) tamoxifen (TAM) is the gold standard used in the treatment of estrogen-dependent breast cancer. Although it significantly benefited women with breast cancer, time-dependent tumor resistance and the risk of endometrium cancer are associated with it. Consequently, there is an urgent need for alternative treatments. PURPOSE: Incorporating the oxime moiety in conjunction with various basic side chains associated with the pharmacophore of the SERMs into estrone may yield various estrone derivatives with antiestrogenic activity. The estrone derivatives were compared to 4-hydroxy-tamoxifen (4-OH-TAM) and raloxifene (RAL). METHODS: The estrone derivatives were synthesized using established chemical procedures. The Southern Research Institute in Birmingham, Alabama carried out the cytotoxicity studies in MCF-7, MDA-MB-231 and Ishikawa cancer cells. They tested different concentrations of the six different estrone derivatives ranging from .01 nM to 100,000 nM on 5000 MCF-7 cells/well, on 5000 MDA-MB-231 cells/well and on 5000 Ishikawa cells/well. Cells pre-treated with the various estrone derivatives were incubated at 37°C for 3 days followed by MTS assay. Their IC50 values were generated using GraphPad Prism 5.0. RESULTS: Our compounds demonstrated anti-proliferative activity in MCF-7 cells but they were not as potent as 4-OH-TAM(2µM) or RAL (3µM). Compounds 2, 3, 4, 6, and 7 (31µM, 29µM, 30µM, 30µM, and 29µM respectively) were comparable in potency to RAL (28µM) in MDA-MB-231 cells but all were not as potent as 4-OH-TAM (22µM). Compounds 3, 6, and 7 (20µM, 20µM, and 17µM respectively) were comparable or greater in potency to 4-OH-TAM (20µM) in Ishikawa cells and compounds 2, 3, 6, and 7 (24µM, 20µM, 20µM, and 17µM respectively) were comparable or greater in potency to RAL (23µM). CONCLUSION: Applying the oxime moiety in conjunction with the pharmacophore of the SERMs to estrone produced agents with antiproliferative activity. They also showed antiproliferative activity in estrogen-receptor negative MDA-MB-231 cells. These results suggest that several of the estrone derivatives show promise as potential anti-breast cancer agents. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3238. doi:10.1158/1538-7445.AM2011-3238

Synthesis and Evaluation of Estradiol Derivatives as Anti-Breast Cancer Agents

3-N-alkyloxyestradiol derivatives were synthesized, characterized and tested for activity in MCF-7 human breast cancer cells. Among the compounds, the diisopropyl and piperidinyl derivatives were found to be more active than 4-hydroxytamoxifen (HO-Tam), the active metabolite of tamoxifen based upon IC(50) values. The IC(50)s were correlated with structures using molecular modeling.

Pharmacokinetic Evaluation of 3′-Azido-2′, 3′-Dideoxyuridine-5′-O-Valinate-Hydrochloride as a Prodrug of the Anti-HIV Nucleoside 3′-Azido-2′, 3′-Dideoxyuridine

3′-Azido-2′, 3′-dideoxyuridine (AZDU, AzddU, CS-87) has been shown to have potent anti-HIV activity in vitro. However, the compound exhibits a relatively short half-life and incomplete oral bioavailability in humans. In an effort to improve the pharmacokinetic properties of AZDU, prodrug 3′-azido-2′,3′-dideoxyuridine-5′-O-valinate hydrochloride (AZDU-VAL) was synthesized by the esterification of 5′-OH function in AZDU. The objective of this study was to investigate the biotransformation and pharmacokinetics of AZDU-VAL along with its antiviral parent compound AZDU following intravenous and oral administration to rats. Adult male Sprague-Dawley rats were administered AZDU or AZDU-VAL by intravenous injection or oral gavage. Concentrations of AZDU-VAL and AZDU were determined by HPLC. Pharmacokinetic parameters were generated by area-moment analysis. The bioavailability of AZDU after oral administration was approximately 53%. The terminal phase half-life of the nucleoside analogue ranged between 0.6 h after intravenous administration and 1 h following oral administration. In vivo the prodrug was rapidly and efficiently biotransformed to yield AZDU following intravenous and oral administration. The apparent availability of AZDU was virtually complete following oral administration of prodrug AZDU-VAL averaging 101%. The bioavailability of AZDU following intravenous administration of AZDU-VAL averaged 106%. In summary, the disposition of AZDU was dose dependent over the dose range of 25–100 mg/kg. Renal clearance and steady state volume of distribution were lower at the higher dose level. Prodrug AZDU-VAL demonstrated improved oral bioavailability as evidenced by complete absorption and efficient bioconversion to AZDU. The results suggest that AZDU-VAL may be a promising prodrug for the delivery of AZDU.