Synthesis of novel substituted pyrimidine derivatives bearing a sulfamide group and their in vitro cancer growth inhibition activity

The synthesis of two series of novel substituted pyrimidine derivatives bearing a sulfamide group have been described and their in vitro cancer growth inhibition activities have been evaluated against three human tumour cell lines (HT-29, M21, and MCF7). In general, growth inhibition activity has been enhanced by the introduction of a bulky substituent on the aromatic ring with the best compound having GI₅₀ < 6 μM for all the human tumour cell lines. The MCF7 selective compounds were evaluated on four additional human invasive breast ductal carcinoma cell lines (MDA-MB-231, MDA-MB-468, SKBR3, and T47D) and were selective against T47D cell line in all cases except one, suggesting a potential antiestrogen activity.     

Modulation of in situ estrogen synthesis by proline-, glutamic acid-, and leucine-rich protein-1: potential estrogen receptor autocrine signaling loop in breast cancer cells

In situ estrogen synthesis is implicated in tumor cell proliferation through autocrine or paracrine mechanisms especially in postmenopausal women. Several recent studies demonstrated activity of aromatase, an enzyme that plays a critical role in estrogen synthesis in breast tumors. Proline-, glutamic acid-, and leucine-rich protein-1 (PELP1/MNAR) is an estrogen receptor (ER) coregulator, and its expression is deregulated in breast tumors. In this study, we examined whether PELP1 promotes tumor growth by promoting local estrogen synthesis using breast cancer cells (MCF7) that stably overexpress PELP1. Immunohistochemistry revealed increased aromatase expression in MCF7-PELP1-induced xenograft tumors. Real-time PCR analysis showed enhanced activation of the aromatase promoter in MCF7-PELP1 clones compared with MCF7 cells. Using a tritiated-water release assay, we demonstrated that MCF7-PELP1 clones exhibit increased aromatase activity compared with control MCF-7 cells. PELP1 deregulation uniquely up-regulated aromatase expression via activation of aromatase promoter I.3/II, and growth factor signaling enhanced PELP1 activation of aromatase. PELP1-mediated induction of aromatase requires functional Src and phosphatidylinositol-3-kinase pathways. Mechanistic studies revealed that PELP1 interactions with ER-related receptor-alpha and proline-rich nuclear receptor coregulatory protein 2 lead to activation of aromatase. Immunohistochemistry analysis of breast tumor array showed increased expression of aromatase in ductal carcinoma in situ and node-positive tumors compared with no or weak expression in normal breast tissue. Fifty-four percent (n = 79) of PELP1-overexpressing tumors also overexpressed aromatase compared with 36% (n = 47) in PELP1 low-expressing tumors. Our results suggest that PELP1 regulation of aromatase represents a novel mechanism for in situ estrogen synthesis leading to tumor proliferation by autocrine loop and open a new avenue for ablating local aromatase activity in breast tumors.     

Metacytofilin has potent anti-malarial activity

Metacytofilin (MCF) was isolated from the fungus Metarhizium sp. TA2759. Although MCF possesses anti-Toxoplasma activity, the effects of this compound against other parasites are unknown. Here, we evaluated the in vitro anti-malarial activity of MCF against the 3D7 strain and the chloroquine-resistant K1 strain of Plasmodium falciparum. The half maximal inhibitory concentrations (IC₅₀) of MCF against the 3D7 and K-1 strains following culture for 48 h were 666 nM and 605 nM, respectively. Artemisinin was more potent than MCF against both strains (3D7 IC₅₀: 17.4 nM; K-1 IC₅₀: 18.3 nM), while chloroquine was ineffective against the chloroquine-resistant strain (3D7 IC₅₀: 39.1 nM; K-1 IC₅₀: 1.62 μM). MCF affected the ring stage of the parasites, resulting in their death as shown by spots within red blood cells. MCF also inhibited parasite growth following culture for 72 h (3D7 IC₅₀, 285 nM). Four optical isomers of cyclo[Leu-Phe]-diketopiperazine derivatives with modified methoxy and/or hydroxyl groups lost anti-malarial activity, suggesting that the spatial positions of the methoxy and hydroxyl groups in MCF play an important role in its anti-malarial effects. Together, these data suggest that MCF may represent a promising lead compound for treatment of drug-resistant malarial parasites.     

Small P-gp modulating molecules: SAR studies on tetrahydroisoquinoline derivatives

The development of small molecules as P-gp modulating agents and SAR studies on these ligands represented the aim of the present work. A series of 6,7-dimethoxytetrahydroisoquinoline derivatives was prepared and their ability to inhibit P-gp activity has been evaluated. The basic nucleus of these compounds, common to the best P-gp inhibitors such as Tariquidar and Elacridar, has been functionalized with no-basic moiety from our studied sigma receptor ligands displaying potent P-gp inhibition. The best results were obtained for compounds 3c and 3a (EC(50)=1.64 and 4.86 microM, respectively) and these results were remarkable because Elacridar showed in the same biological evaluation similar inhibitory activity (EC(50)=2 microM). SAR studies displayed that the removal of double bond on the spacer or its shifting into tetraline ring decreased the P-gp inhibiting activity. Moreover, the P-gp inhibition mechanism of tested compounds was investigated by three selected biological experiments. The results displayed that only compound 3c was P-gp inhibitor as Elacridar, while compound 3a and reference compounds Cyclosporin A and Verapamil modulated P-gp activity saturating the efflux pump as substrates. Flow cytometry studies carried out in Doxorubicin resistant breast cancer cell line (MCF7/Adr) confirmed that compound 3c increased Doxorubicin cell accumulation 5.7-fold. In addition, in MCF7/Adr, antiproliferative effect of 5 microM Doxorubicin shifted from 5% to 95% when co-administered with compound 3c (20 microM). The present study suggested a new class of small molecules displaying P-gp inhibitor activity differing from reference compounds Elacridar and Tariquidar for a simplified, and in the meantime, efficacious no-basic moiety.     

Amino acid starvation sensitizes cancer cells to proteasome inhibition

We explored the crosstalk between protein degradation and synthesis in cancer cells. The tumorigenic cell line, MCF7, showed enhanced proteasome activity compared to the nontumorigenic line, MCF10A. Although there was no difference in the sensitivity of MCF7 and MCF10A cells to proteasome inhibition in complete growth medium, combining proteasome inhibition with amino acid deprivation led to reduced protein synthesis and survival of MCF7 cells, with a lesser effect on MCF10A cells. Additional cancer cell lines (including CAG and A431) could be strongly sensitized to proteasome inhibition by concomitant amino acid deprivation, whereas others were completely resistant to proteasome inhibition. We hypothesize that protein catabolism contributes to the pool of free amino acids available for protein synthesis, leading to a crucial role of the proteasome in cell survival during amino acid depletion, in some tumor cell lines.     

First synthesis of 3,16,20-polyoxygenated cholestanes, new cytotoxic steroids from the gorgonian Leptogorgia sarmentosa

Using tigogenin as starting material, (20S)-20-hydroxycholestane-3,6-dione (1), (16S, 20S)-16,20-dihydroxycholestan-3-one (2), (20S)-20-hydroxycholest-1-ene-3,16-dione (3) and (20S)-20-hydroxycholest-4-ene-3,16-dione (4), natural polyoxygenated steroids from the gorgonian, Leptogorgia sarmentosa, were synthesized in four steps. Antitumor activity against three tumor cell lines (breast cancer, MCF7, lung cancer NCI and oral cancer KB) was evaluated. Two compounds (3 and 4) showed strong activity against NCI (IC(50) 6.16 and 10.51 microM) and moderate activity against MCF7 and KB, the IC(50) being in the range 30.65-47.22 microM. Compound 2 showed moderate activity against NCI (IC(50) 42.68 microM) but was inactive against MCF7 and KB whereas compound 1 showed no activity against all tested cells.     

Synthesis and antitumor activity of tetrahydrocarbazole hybridized with dithioate derivatives

Abstract

The present study reported the synthesis of tetrahydrocarbazoles hybridized with dithioate derivatives. Three series were synthesized namely alkyl dithiocarbonates (4a–d), heterocyclic dithiocarbamates (6a–g) and dialkyl dithiocarbamate (7). The synthesized compounds were tested in vitro on human breast adenocarcinoma cell line (MCF7) and the human colon tumor cell line (HCT116). Most of the synthesized compounds exploited potent antitumor activity, especially compound 6f [4-chlorophenylpiperazine derivative], which showed cytotoxic activity against MCF7 superior to doxorubicin with IC₅₀ value of 7.24?nM/mL.     

Antiproliferative activity of chalcones with basic functionalities

A library of chalcones with different basic groups were synthesized and evaluated for antiproliferative activities against the human breast cancer (MCF 7) and colon cancer (HCT 116) cell lines. Structure-activity relationships were analyzed by projection methods (PCA/PLS) and multiple linear regression. Polar volume, hydrogen bonding features, HOMO energies, and charge on the beta carbon were found to be important factors. A basic group on either ring A or B of the chalcone led to a favourable increase in polar volume, but when present on ring B, it increased HOMO energies and decreased the positive charge on the beta carbon, both of which led to lower activity. Several examples showed that final activity of the chalcone was influenced by compensatory interactions among these parameters. In general, a single basic group on ring A was associated with good activity. A notable exception was compound 1-123 which had basic groups on both rings A and B but still maintained a good activity profile with IC(50)<10 microM and selectivity ratios >2.5. There was some evidence to show that structural differences in chalcones influenced not only activity but mechanism of action. Compounds 6-130 and 7-140 which had basic groups on ring A interfered with cell cycle progression, but the dibasic chalcone 1-123 had no effect.     

Synthesis, tubulin assembly, and antiproliferative activity against MCF7 and NCI/ADR-RES cancer cells of 10-O-acetyl-5'-hydroxybutitaxel

A highly efficient kinetic resolution of racemic cis-4-(2-tert-butyldimethylsilyloxy-1,1-dimethyl)ethyl-3-tert-butyldimethylsilyloxy-azetidin-2-one with 7-O-triethylsilylbaccatin III was carried out to furnish 10-O-acetyl-5'-hydroxybutitaxel after removal of the silyl protecting groups. The compound was 50% as active as paclitaxel in a tubulin assembly assay and showed significantly decreased activity against MCF7 cell proliferation compared to paclitaxel.     

Synthesis and biological evaluation of novel synthetic chalcone derivatives as anti-tumor agents targeting Cat L and Cat K

A series of chalcone derivatives bearing benzamide or benzenesulfonamide moieties were synthesized and evaluated for their anti-tumor effect on HCT116, MCF7 and 143B cell lines in vitro. SAR analysis showed that compounds bearing a benzenesulfonamide group had greater potency than those bearing a benzamide group. It was also shown that compounds with a mono-methyl or mono-halogen group at the 3-position on the terminal phenyl ring were more effective than those with trifluoromethyl or methoxy groups. Compound 8e exhibited the most potent anti-tumor activities against HCT116, MCF7 and 143B cell lines, with IC₅₀ values of 0.597, 0.886 and 0.791 μM, respectively. Molecular docking studies and enzymatic assays demonstrated that the anti-tumor activity of compound 8e might be regulated by Cat L and Cat K.     

Further study on synthesis and evaluation of 3,16,20-polyoxygenated steroids of marine origin and their analogs as potent cytotoxic agents

A series of new polyoxygenated steroid derivatives with various steroid skeleton moieties were synthesized. Antitumor activity of the compounds against three tumor cell lines (Breast cancer MCF7, lung cancer NCI and oral cancer KB) were evaluated. Compounds with aromatic A ring of this series exhibited the most potent cytotoxicities in all tested cells. The absence of OH at C-16 or lack of cholesterol like side chain at C-20 in the steroid skeleton apparently result in decreased cytotoxicity. The compound became inactive when the side chain contains double bond at C-24-C-25. When hydroxyl group at C-3 was protected no cytotoxicities against MCF7 and NCI and considerable low cytotoxicity against KB cell lines were observed.     

Synthesis,characterization and cytotoxicity studies of 1,2,3-triazoles and 1,2,4-triazolo [1,5-a] pyrimidines in human breast cancer cells

Vascular endothelial growth factor (VEGF) and its receptor (VEGFR) is essential for physiological functions of tissues and neovasculature. VEGFR signaling is associated with the progression of pathological angiogenesis in various types of malignancies, making it an attractive therapeutic target in cancer treatment. In the present work, we report the synthesis of 1,4-disubstituted 1,2,3-triazoles and 1,2,4-triazolo[1, 5-a]pyrimidine derivatives via copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction and screened for their anticancer activity against MCF7 cells. We identified 1-(2′-ethoxy-4′-fluoro-[1,1′-biphenyl]-4-yl)-4-phenyl-1H-1,2,3-triazole (EFT) as lead cytotoxic agent against MCF7 cell lines with an IC₅₀ value of 1.69?µM. Further evaluation revealed that EFT induces cytotoxicity on Ishikawa, MDA-MB-231 and BT474 cells with IC₅₀ values of 1.97, 4.81 and 4.08?µM respectively. However, EFT did not induce cytotoxicity in normal lung epithelial (BEAS-2B) cells. Previous reports suggested that 1,2,3-triazoles are the inhibitors of VEGFR1 and therefore, we evaluated the effect of EFT on the expression of VEGFR1. The results demonstrated that EFT downregulates the expression of VEGFR1 in MCF7 cells. In summary, we identified a potent cytotoxic agent that imparts its antiproliferative activity by targeting VEGFR1 in breast cancer cells. The novel compound could serve as a lead structure in developing VEGFR1 inhibitors.     

Microbiological transformation of mycophenolic acid

In our microbial screening program, we have isolated a fungal strain which produced mycophenolic acid (MPA). This compound is a selective inhibitor of guanine synthesis and, therefore, it has antibacterial, antiviral, antitumor and selective immunosuppressive activities, too. This last effect was utilised by Roche-Syntex to develop a derivative of MPA to the immunosuppressive drug CellCept®.

In order to obtain novel derivatives of MPA with an enhanced activity, we applied bioconversion of MPA with various microorganisms. TLC with densitometric evaluation and HPLC methods were developed for measurement of MPA derivatives. In the course of the bioconversion of MPA by using various types of microorganisms amidation of the carboxyl group, hydroxylation of the C₄-methyl group and formation of glycoside derivatives from the hydroxyl group located on C₇ were observed as the most frequently occurring transformations. The structures of bioconversion products were determined by UV, IR, ¹H NMR, ¹³C NMR and mass spectroscopic methods.

The taxonomic features of cultures of the species applied in the bioconversion were also determined.     

Development of pyridine-containing macrocyclic copper(II) complexes: potential role in the redox modulation of oxaliplatin toxicity in human breast cells

The unique redox and catalytic chemistry of Cu has justified the development of novel Cu complexes for different therapeutic uses including cancer therapy. In this work, four pyridine-containing aza-macrocyclic copper(II) complexes were prepared (CuL1-CuL4) varying in ring size and/or substituents and their superoxide scavenging activity evaluated. CuL3, the most active superoxide scavenger, was further studied as a modulator of the cytotoxicity of oxaliplatin in epithelial breast MCF10A cells and in MCF7 breast cancer cells. Our results show that CuL3 enhances the therapeutic window of oxaliplatin, by both protecting non-tumour cells and increasing its cytotoxic effect in breast carcinoma cells. CuL3 is thus a promising complex to be further studied and to be used as a lead compound for the optimization of novel chemotherapy sensitizers.     

Synthesis and anticancer activity of analogues of phenstatin,with a phenothiazine A-ring,as a new class of microtubule-targeting agents

A new family of microtubule-targeting agents with a phenothiazine A-ring was synthesized and evaluated for anti-proliferative activity and interaction with tubulin. These new derivatives showed significant activities against cellular proliferation and tubulin polymerization, rather similar to those of phenstatin. Phenothiazine derivative 21 proved to be the most potent compound synthesized with GI₅₀ values ranging from 29 to 93 nM on different cell lines. The same compound showed a better inhibition of COLO 205, A498, and MCF7 cell lines than the parent phenstatin.     

Synthesis,Molecular Modeling,and Biological Evaluation of Novel Chiral Thiosemicarbazone Derivatives as Potent Anticancer Agents

A series of new chiral thiosemicarbazones derived from homochiral amines in both enantiomeric forms were synthesized and evaluated for their in vitro antiproliferative activity against A549 (human alveolar adenocarcinoma), MCF‐7 (human breast adenocarcinoma), HeLa (human cervical adenocarcinoma), and HGC‐27 (human stomach carcinoma) cell lines. Some of compounds showed inhibitory activities on the growth of cancer cell lines. Especially, compound 17b exhibited the most potent activity (IC₅₀ 4.6 μM) against HGC‐27 as compared with the reference compound, sindaxel (IC₅₀ 10.3 μM), and could be used as a lead compound to search new chiral thiosemicarbazone derivatives as antiproliferative agents. Chirality 27:177–188, 2015. © 2014 Wiley Periodicals, Inc.     

Nitric oxide releasing acridone carboxamide derivatives as reverters of doxorubicin resistance in MCF7/Dx cancer cells

A series of nitric oxide donating acridone derivatives are synthesized and evaluated for in vitro cytotoxic activity against different sensitive and resistant cancer cell lines MCF7/Wt, MCF7/Mr (BCRP overexpression) and MCF7/Dx (P-gp expression). The results showed that NO-donating acridones are potent against both the sensitive and resistant cells. Structure activity relationship indicate that the nitric oxide donating moiety connected through a butyl chain at N¹⁰ position as well as morpholino moiety linkage through an amide bridge on the acridone ring system at C-2 position, are required to exert a good cytotoxic effect. Further, good correlations were observed when cytotoxic properties were compared with in vitro nitric oxide release rate, nitric oxide donating group potentiated the cytotoxic effect of the acridone derivatives. Exogenous release of nitric oxide by NO donating acridones enhanced the accumulation of doxorubicin in MCF7/Dx cell lines when it was coadministered with doxorubicin, which inhibited the efflux process of doxorubicin. In summary, a nitric oxide donating group can potentiate the anti-MDR property of acridones.     

4-substituted indazoles as new inhibitors of neuronal nitric oxide synthase

A series of halo-1-H-indazoles has been synthesized and evaluated for its inhibitory activity on neuronal nitric oxide synthase. Introduction of bromine at the C4 position of the indazole ring system provided a compound almost as potent as the reference compound, that is, 7-nitroindazole (7-NI). The importance of position 4 is further demonstrated by the synthesis and pharmacological evaluation of the 4-nitroindazole which was also a potent inhibitor of NOS activity. These compounds also exhibited in vivo NOS inhibitory activity, as attested by potent antinociceptive effects following systemic administration.     

Development of pyridine-containing macrocyclic copper(II) complexes: potential role in the redox modulation of oxaliplatin toxicity in human breast cells

Abstract

The unique redox and catalytic chemistry of Cu has justified the development of novel Cu complexes for different therapeutic uses including cancer therapy. In this work, four pyridine-containing aza-macrocyclic copper(II) complexes were prepared (CuL1–CuL4) varying in ring size and/or substituents and their superoxide scavenging activity evaluated. CuL3, the most active superoxide scavenger, was further studied as a modulator of the cytotoxicity of oxaliplatin in epithelial breast MCF10A cells and in MCF7 breast cancer cells. Our results show that CuL3 enhances the therapeutic window of oxaliplatin, by both protecting non-tumour cells and increasing its cytotoxic effect in breast carcinoma cells. CuL3 is thus a promising complex to be further studied and to be used as a lead compound for the optimization of novel chemotherapy sensitizers.     

Synthesis and cytotoxic evaluation of novel paraconic acid analogs

A novel class of 2,3-tri- and tetrasubstituted γ-butyrolactones analogous to paraconic acids has been synthesized in one step using a straightforward three-component reaction among aryl bromides, dimethyl itaconate and carbonyl compounds. The in vitro cytotoxic activity of representative compounds has been evaluated against a panel of human cancer cell lines (KB, HCT116, MCF7, HL60). While most molecules exhibit a low to moderate background activity on both KB and HL60 cancer cell lines, one compound shows increased antiproliferative activities against both cell lines with IC(50) values in the 10(-7)-10(-6)mol/L range. An extended evaluation indicated that this compound also inhibits PC3, SK-OV3, MCF7R and HL60R cell growth in the same fashion.