Hsu Shan Huang

Synthesis, cytotoxicity and human telomerase inhibition activities of a series of 1,2-heteroannelated anthraquinones and anthra[1,2-d]imidazole-6,11-dione homologues

A series of 1,2-heteroannelated anthraquinones and anthra[1,2-d]imidazole-6,11-dione tetracyclic analogues with different side chain were prepared using an various synthetic route via acylation, cyclization, condensation, and intramolecular heterocyclization. Tetracyclic system containing alkyl and aryl, aromatic and heterocyclic, linear and cyclic, polar and apolar, and basic and acids residues were incorporated. They were evaluated for their effects on telomerase activity, hTERT expression, cell proliferations, and in vitro cytotoxicity against NCIs 60 cell line human tumor screen. Compounds 4, 11, 12, 14, 15, 16, 17, 19, 20, 23, 25, and 26 were selected by the NCI for one dose screening program and further studies on 4, 23 and 25 where the curves cross these lines represent the interpolated values to cause 50% growth inhibition (GI(50)), total growth inhibition (TGI) and 50% cell killing (LC(50)), respectively. Further studies did not reveal any compound that showed potent and significant on telomerase inhibitory activity and hTERT repressing ability. Comparative testing of these compounds in the NCIs screen revealed varying levels of potency and differential cytotoxicity, apparently related to the unsaturation levels in and substitution patterns on the core ring system. It appeared that addition of a fourth planar aromatic system to a tricyclic chromophore might enhances potent cytotoxic agents, at a level equivalent to a second side chain in one of the tricyclic series. Although the exact mechanism of how this pharmacophore contributes to its activity is still unclear, however, the group in the extended arm of the tetracyclic system might contribute to proper binding to the residues within the grove of G-quadruplex structure.

Synthesis and cytotoxic properties of 4,11 -bis[(aminoethyl)amino]anthra-[2,3-b]thiophene-5,10-diones, novel analogues of antitumor anthracene-9,10-diones

We developed the synthesis of a series of thiophene-fused tetracyclic analogues of the antitumor drug ametantrone. The reactions included nucleophilic substitution of methoxy groups in 4,11-dimethoxyanthra[2,3-b]thiophene-5,10-diones with ethylenediamines, producing the derivatives of 4,11-diaminoanthra[2,3-b]thiophene-5,10-dione in good yields. Several compounds showed marked antiproliferative potency against doxorubicin-selected, P-glycoprotein-expressing tumor cells and p53(-/-) cells. The cytotoxicity of some novel compounds for P-glycoprotein-positive cells is highly dependent on N-substituent at the terminal amino group of ethylenediamine moiety. The cytotoxic potency of selected compounds correlated with their ability to attenuate the functions of topoisomerase I and telomerase, strongly suggesting that these enzymes are the major targets of antitumor activity of anthra[2,3-b]thiophene-5,10-dione derivatives.

Structure-based design, synthesis and evaluation of novel anthra[1,2-d]imidazole-6,11-dione derivatives as telomerase inhibitors and potential for cancer polypharmacology

A series of anthra[1,2-d]imidazole-6,11-dione derivatives were synthesized and evaluated for telomerase inhibition, hTERT expression and suppression of cancer cell growth in vitro. All of the compounds tested, except for compounds 4, 7, 16, 24, 27 and 28 were selected by the NCI screening system. Among them, compounds 16, 39, and 40 repressed hTERT expression without greatly affecting cell growth, suggesting for the selectivity toward hTERT expression. Taken together, our findings indicated that the analysis of cytotoxicity and telomerase inhibition might provide information applicable for further developing potential telomerase and polypharmacological targeting strategy.

The first series of 4,11-bis[(2-aminoethyl)amino]anthra[2,3-b]furan-5,10-diones: Synthesis and anti-proliferative characteristics

We developed the synthesis of a series of furan-fused tetracyclic analogues of the antitumor agent ametantrone. The reactions included nucleophilic substitution of propoxy groups in 4,11-dipropoxyanthra[2,3-b]furan-5,10-diones with ethylenediamines, producing the derivatives of 4,11-diaminoanthra[2,3-b]furan-5,10-dione in good yields. Studies of anti-proliferative activity on a panel of mammalian tumor cell lines demonstrated that anthra[2,3-b]furan-5,10-diones were the most potent derivatives among heteroarene-fused ametantrone analogues with one heteroatom. We identified several compounds that evoked a growth inhibitory effect at submicromolar concentrations. The anthra[2,3-b]furan-5,10-dione 9 with distal methylamino groups was markedly potent against drug-resistant cell lines with P-glycoprotein overexpression or p53 gene deletion. Furthermore, this derivative attenuated in vitro topoisomerase I-mediated DNA uncoiling at low micromolar concentrations. These results demonstrate that anthrafurandiones are a new class of heterocyclic anthraquinone derivatives with the properties potentially valuable for anticancer therapy.

Synthesis, antiproliferative activities and telomerase inhibition evaluation of novel asymmetrical 1,2-disubstituted amidoanthraquinone derivatives.

A series of diversely asymmetrical mono- or disubstituted 1,2-diamidoanthraquinone derivatives were synthesized and evaluated for drug-induced cytotoxicity by SRB assay, telomerase inhibitory activity by TRAP assay, and hTERT expression by SEAP assay. Interestingly, compounds 4, 11, 21, 32 and 36 exhibited selective potent antiproliferative activities by NCI with IC(50) values in the micromolar range. Of these, only compound 8 showed an IC(50) value of 0.95xa0μM against PC-3 cell lines (human prostate cancer) by SRB assay. All the synthesized compounds exhibited a poor or modest telomerase inhibitory activity by TRAP assay suggesting another mode of action for these compounds. Compound 11 showed broad inhibition against different types of cancer cell lines in the micromolar and submicromolar range.

Design, synthesis and evaluation of telomerase inhibitory, hTERT repressing, and anti-proliferation activities of symmetrical 1,8-disubstituted amidoanthraquinones

A series of symmetrical disubstituded 1,8-diamidoanthraquinones were synthesized and evaluated for anti-proliferation, telomerase inhibitory by TRAP assay, and hTERT expression by SEAP assay. All of the compounds tested, except for compounds 3a and 3s were selected by the NCI screening system. In addition, compounds 4e and 4k exhibited inhibitory effects on telomerase activity. Taken together, our findings indicated that the analysis of cytotoxicity and telomerase inhibition might provide information applicable for further developing potential telomerase targeting strategy.

Design, synthesis and antiproliferative evaluation of fluorenone analogs with DNA topoisomerase I inhibitory properties.

A series of 2,7-diamidofluorenones were designed, synthesized, and screened by SRB assay. Some synthesized compounds exhibited antitumor activities in submicromolar range. Ten compounds (3a, 3b, 3c, 3g, 3j, 3l, 4a, 4h, 4i, and 4j) were also selected by NCI screening system and 3c (GI50=1.66 μM) appeared to be the most active agent of this series. Furthermore, 3c attenuated topoisomerase I-mediated DNA relaxation at low micromolar concentrations. These results indicated that fluorenones have potential to be further developed into anticancer drugs.