Identification of quinone analogues as potential inhibitors of picornavirus 3C protease in vitro.

Picornaviruses are non-enveloped viruses that represent a large family of positive-sense single-stranded RNA viruses including a number of causative agents of many human and animal diseases such as coxsackievirus B3 (CVB3) and rhinoviruses (HRV). In this study, we performed a high-throughput screening of a compound library composed of ∼6000 small molecules in search of potential picornavirus 3C protease (3Cpro) inhibitors. As results, we identified quinone analogues that effectively inhibited both CVB3 3Cpro and HRV 3Cpro with IC50 values in low micromolar range. Together with predicted binding modes of these compounds to the active site of the viral protease, it is implied that structural features of these non-peptidic inhibitors may act as useful scaffold for further anti-picornavirus drug design and development.

Synthesis of antifungal evaluation of 2H-[1,2,3]Triazolo[4,5-g]isoquinoline-4,9-diones.

2H-[1,2,3]Triazolo[4,5-g]isoquinoline-4,9-diones and 2H-[1,2,3]triazolo[4,5-g]quinoline-4,9-diones were synthesized and tested for in vitro antifungal activity against pathogenic fungi. Many of those synthesized showed potent antifungal activity. Compounds 3a, 3b, 3g, and 3h completely inhibited the growth of all fungal species tested at the MIC level of 0.8-12.5 µg/mL. The results suggest that 2H-[1,2,3]triazolo[4,5-g]isoquinoline-4,9-diones could be antifungal agents.

Synthesis of benzofuro[6,7-d]thiazoles, benzofuro[7,6-d]thiazoles and 6-arylaminobenzo[d]thiazole-4,7-diones as antifungal agent.

Benzofuro[6,7-d]thiazoles, benzofuro[7,6-d]thiazoles and 6-arylaminobenzo[d]thiazole-4,7-diones were synthesized and tested for in vitro antifungal activity against Candida, Aspergillus species and Cryptococcus neoformans. Among them tested, many of synthesized compounds showed potent antifungal activity. The compounds 4d, 6e and 6h completely inhibited the growth of all Candida and Aspergillus species tested at the MIC level of 6.3 µg/mL. The results suggest that benzofuro[6,7-d]thiazoles and 6-arylaminobenzo[d]thiazole-4,7-diones would be promising antifungal agents.

The discovery of aurora kinase inhibitor by multi-docking-based virtual screening.

We report the discovery of aurora kinase inhibitor using the fragment-based virtual screening by multi-docking strategy. Among a number of fragments collected from eMololecules, we found four fragment molecules showing potent activity (>50% at 100 µM) against aurora kinase. Based on the explored fragment scaffold, we selected two compounds in our synthesized library and validated the biological activity against Aurora kinase.

Synthesis and antifungal evaluation of 7-arylamino-5,8-dioxo-5,8-dihydroisoquinoline-4-carboxylates.

7-Arylamino-5,8-dioxo-5,8-dihydroisoquinoline-4-carboxylates were synthesized and tested for in vitro antifungal activity against two pathogenic strains of fungi. Most of tested compounds showed good antifungal activity. The results suggest that those 5,8-dioxo-5,8-dihydroisoquinolines would be potent antifungal agents.

Synthesis and antifungal activity of 1-thia-4b-aza-cyclopenta[b]fluorene-4,10-diones.

1-Thia-4b-aza-cyclopenta[b]fluorene-4,10-diones were synthesized and tested for in vitro antifungal activity against two pathogenic strains of fungi. Among them tested, many compounds showed good antifungal activity. The results suggest that 1-thia-4b-aza-cyclopenta[b]fluorene-4,10-diones would be antifungal agents.

Synthesis and antifungal evaluation of pyrido[1,2-a]indole-1,4-diones and benzo[f]pyrido[1,2-a]indole-6,11-diones.

Pyrido[1,2-a]indole-1,4-diones and benzo[f]pyrido[1,2-a]indole-6,11-diones were synthesized and tested for in vitro antifungal activity against two pathogenic strains of fungi. Among them tested, many compounds showed good antifungal activity. The results suggest that pyrido[1,2-a]indole-1,4-diones and benzo[f]pyrido[1,2-a]indole-6,11-diones would be potent antifungal agents.

Synthesis and antifungal activity of 6,7-bis(arylthio)-quinazoline-5,8-diones and furo[2,3-f]quinazolin-5-ols.

6,7-Bis(arylthio)-quinazoline-5,8-dione and furo[2,3-f]quinazolin-5-ol derivatives were synthesized and tested for in vitro antifungal activity against Candida, Aspergillus species, and Cryptococcus neoformans. Among them tested, many of furo[2,3-f]quinazolin-5-ols and 6,7-bis(arylthio)-quinazoline-5,8-diones showed good antifungal activity. The compounds completely inhibited the growth of all against Candida and Aspergillus species tested at the MIC level of 12.5µg/mL. The results suggest that furo[2,3-f]quinazolin-5-ols and 6,7-bis(arylthio)-quinazoline-5,8-diones would be promising antifungal agents.

Synthesis and antifungal activity of furo[2,3-f]quinolin-5-ols.

Furo[2,3-f]quinolin-5-ol derivatives were synthesized and tested for in vitro antifungal activity against Candida,Aspergillus species, and Cryptococcus neoformans. Among them tested, many furo[2,3-f]quinolin-5-ols showed good antifungal activity. The results suggest that furo[2,3-f]quinolin-5-ols would be promising antifungal agents.

Synthesis and antifungal evaluation of 6-hydroxy-1H-carbazole-1,4(9H)-diones.

6-Hydroxy-1H-carbazole-1,4(9H)-diones were synthesized and tested for in vitro antifungal activity against two pathogenic strains of fungi. Among them tested, many compounds showed good antifungal activity. The results suggest that 6-hydroxy-1H-carbazole-1,4(9H)-diones would be potent antifungal agents.

Synthesis and antifungal activity of benzofuran-5-ols.

Benzofuran-5-ol derivatives were synthesized and tested for in vitro antifungal activity against Candida, Aspergillus species, and Cryptococcus neoformans. Among them tested, many benzofuran-5-ols showed good antifungal activity. The results suggest that benzofuran-5-ols would be promising antifungal agents.

Synthesis and antifungal activity of 1H-pyrrolo[3,2-g]quinoline-4,9-diones and 4,9-dioxo-4,9-dihydro-1H-benzo[f]indoles.

1H-Pyrrolo[3,2-g]quinoline-4,9-diones and 4,9-dioxo-4,9-dihydro-1H-benzo[f]indoles were synthesized and tested for in vitro antifungal activity against fungi. Among them tested, many compounds showed good antifungal activity. The results suggest that 1H-pyrrolo[3,2-g]quinoline-4,9-diones and 4,9-dioxo-4,9-dihydro-1H-benzo[f]indoles would be potent antifungal agents.

Synthesis and antifungal activity of benzo[d]oxazole-4,7-diones.

Benzo[d]oxazole-4,7-diones were synthesized and tested for in vitro antifungal activity against fungi. Among them tested, many compounds showed good antifungal activity. The results suggest that benzo[d]oxazole-4,7-diones would be potent antifungal agents.

YSK2821, a newly synthesized indoledione derivative, inhibits cell proliferation and cell cycle progression via the cell cycle-related proteins by regulating phosphatidylinositol-3 kinase cascade in vascular smooth muscle cells.

Indoledione derivatives have pronounced biological effects, i.e., cytotoxic activities against cancer cell lines and antifungal and antibacterial activities. The present study was designed to investigate the effects of YSK2821, a newly synthesized indoledione derivative, on platelet-derived growth factor (PDGF-BB)-induced vascular smooth muscle cell (VSMC) proliferation, as well as the molecular mechanisms of the anti-proliferative effects of YSK2821 in VSMCs. We found that YSK2821 caused the accumulation of cells in the G1 phase of the cell cycle and inhibited [3H]-thymidine incorporation. We demonstrated that YSK2821 remarkably decreased Akt kinase phosphorylation as the mechanism by which YSK2821 suppressed cell signal transduction events in VSMC proliferation. Furthermore, in terms of the effects of YSK2821 on cell cycle-related proteins, YSK2821 enhanced the expression of the cyclin-dependent protein kinase (CDK) inhibitor p27 and down-regulated CDK2 and cyclin E expression, but did not affect CDK4 and cyclin D1 expression. YSK2821 also inhibited the phosphorylation of Rb, a key regulator in the cell cycle. These results indicate that YSK2821, a newly synthesized indoledione derivative, may inhibit VSMC proliferation via a phosphatidylinositol (PI)-3 kinase-dependent pathway, and thus shed light on a novel role for YSK2821 as a potential preventive regulator of cardiovascular disease.

Design, synthesis and evaluation of 2-phenyl-1H-benzo[d]imidazole-4,7-diones as vascular smooth muscle cell proliferation inhibitors.

A series of 2-phenyl-1H-benzo[d]imidazole-4,7-diones were synthesized and tested for their inhibitory activity on the PDGF-stimulated proliferation of rat aortic vascular smooth muscle cells. Among the tested compounds, 6-arylthio-5-chloro-2-phenyl-1H-benzo[d]imidazole-4,7-diones exhibited an potent antiproliferative activity.

3D-QSAR studies of heterocyclic quinones with inhibitory activity on vascular smooth muscle cell proliferation using pharmacophore-based alignment.

The abnormal proliferation and migration of vascular smooth muscle cells (SMCs) play an important role in the pathology of coronary artery atherosclerosis and restenosis following angioplasty. It was reported that some heterocyclic quinone derivatives such as 6-arylamino-quinoxaline-5,8-diones and 6-arylamino-1H-benzo[d]imidazole-4,7-diones have inhibitory activity on rat aortic smooth muscle cell (RAoSMC) proliferation. To understand the structural basis for antiproliferative activity to design more potent agents, we generated pharmacophore models of representative molecules with high activity using Genetic Algorithm with Linear Assignment of Hypermolecular Alignment of Database (GALAHAD) and aligned a series of compounds to the selected pharmacophore model, then performed three-dimensional quantitative structure-activity relationship (3D-QSAR) studies using Comparative Molecular Field Analysis (CoMFA) and Comparative Molecular Similarity Indices Analysis (CoMSIA). Good cross-validated correlations were obtained with CoMFA (resulting in q(2) of 0.734 and r(2) of 0.947) and CoMSIA (resulting in q(2) of 0.736 and r(2) of 0.913). The IC(50) values of the heterocyclic quinone derivatives on RAoSMC exhibited a strong correlation with steric and hydrophobic fields of the 3D structure of the molecules, resulting in the reliable prediction of inhibitory activity of the series of compounds.

Antiproliferative effects of 6-anilino-5-chloro-1H-benzo[d]imidazole-4,7-dione in vascular smooth muscle cells.

It has been known that benzimidazol-4,7-diones have antiproliferative activity against various cancer cell lines. Recently, we have also reported that these compounds strongly inhibited the proliferation of vascular smooth muscle cell (SMC) and human umbilical vein endothelial cells (HUVECs). Although benzimidazol-4,7-diones have important biological activities, the molecular mechanism of the compounds in these cells remains to be elucidated. In order to investigate the anti-proliferation mechanism of the compounds in smooth muscle cell, we selected 6-anilino-6-chloro-5-chloro-1H-benzo{d}midazole-4,7-dione (BUD-0203) among 12 benzimidazol-4,7-dione derivatives and examined its antiproliferative effects. Phosphorylation of the extracellular-signal regulated kinase (ERK) reached a maximal level at 1h after treatment with BUD-0203 and was sustained during the examined period. We also observed that phosphorylation of p38 reached a maximal level at 4h and decreased to control levels after 8h. These results showed that BUD-0203 sustainedly activated MAP kinase pathways in SMC. However, this compound did not induce cell cycle arrest in G1 or G2 phase in these cells. We also demonstrated that BUD-0203 not only induced apoptosis of SMC, but it also strongly inhibited SMC migration induced by platelet-derived growth factor (PDGF) or serum. Taken together, our experiments indicate that benzimidazol-4,7-diones induce apoptosis of smooth muscle cell via simultaneously prolonged activation of MAP kinase pathways including ERK, p38, and JNK/SAPK, similar with the apoptosis mechanism reported previously.

Induction of immunogenic cell death of tumors by newly synthesized heterocyclic quinone derivative.

Many cancer types are serious diseases causing mortality, and new therapeutics with improved efficacy and safety are required. Immuno-(cell)-therapy is considered as one of the promising therapeutic strategies for curing intractable cancer. In this study, we tested R2016, a newly developed heterocyclic quinone derivative, for induction of immunogenic tumor cell death and as a possible novel immunochemotherapeutic. We studied the anti-cancer effects of R2016 against LLC, a lung cancer cell line and B16F10, a melanoma cell line. LLC (non-immunogenic) and B16F10 (immunogenic) cells were killed by R2016 in dose-dependent manner. R2016 reduced the viability of both LLC and B16F10 tumor cells by inducing apoptosis and necrosis, while it demonstrated no cytotoxicity against normal splenocytes. Expression of immunogenic death markers on the cell surface of R2016 treated tumor cells including calreticulin (CRT) and heat shock proteins (HSPs) was increased along with the induction of their genes. Increased CRT expression correlated with dendritic cell (DC) uptake of dying tumor cells: the proportion of CRT+CD11c+cells was increased in the R2016-treated group. The gene transcription of Calr3, Hspb1, and Tnfaip6, which are related to immunogenicity induction of dead cells, was up-regulated in the R2016 treated tumor cells. On the other hand, ANGPT1, FGF7, and URGCP gene levels were down-regulated by R2016 treatment. This data suggests that R2016 induced immunogenic tumor cell death, and suggests R2016 as an effective anti-tumor immunochemotherapeutic modality.

Synthesis and antifungal activity of 2/3-arylthio- and 2,3-bis(arylthio)-5-hydroxy-/5-methoxy-1,4-naphthoquinones.

2/3-Arylthio- and 2,3-bis(arylthio)-5-hydroxy-/5-methoxy-1,4-naphthoquinones 5-9 were synthesized and tested for in vitro antifungal activity against Candida species and Aspergillus niger. The synthesized compounds 5-9 generally showed good activities against Candida albicans and C. tropicalis. The results suggest that the 1,4-naphthoquinones 5-9 would be potent antifungal agents.

Synthesis and antifungal activity of naphthalene-1,4-diones modified at positions 2, 3, and 5.

A series of 2-arylamino-5-hydroxy-naphthalene-1,4-diones, 3-arylamino-5-methoxy-naphthalene-1,4-diones, and 2-arylamino-3chloro-5-hydroxy-naphthalene-1,4-diones were synthesized and tested for in vitro antifungal activity against the species Candida and Aspergillus niger. Among those tested, 3-arylamino-5-methoxy-naphthalene-1,4-diones exhibited potent antifungal activity. In general, the 3-arylamino-5-methoxy-naphthalene-1,4-diones showed more potent antifungal activity than the 2-arylamino-5-hydroxy-naphthalene-1,4-diones and the 2-arylamino-3-chloro-5-hydroxy-naphthalene-1,4-diones.