Suk Hee Cho

Virtual screening and synthesis of quinazolines as novel JAK2 inhibitors.

JAK2 is an important target in multiple processes associated with tumor growth. In this study, virtual screening was employed for hit compound identification with chemical libraries using SurflexDock. Subsequently, hit optimization for potent and selective candidate JAK2 inhibitors was performed through synthesis of diverse C-1 substituted quinazoline derivatives. A novel compound 5p, (6,7-dimethoxyquinazolin-4-yl)naphthalen-1-ylamine, was thus obtained. JAK2 inhibitory activity of 5p was 43% at 20μM and this was comparable to AG490, a representative JAK2 inhibitor. Moreover, 5p showed a positive correlation between JAK2 inhibition and cytotoxicity; 5p treatment in HT-29 cells strongly inhibited JAK2 activation and subsequent STAT3 phosphorylation, reduced anti-apoptotic protein levels, and finally induced apoptosis. This suggests that compound 5p is a candidate inhibitor of JAK2 and its downstream STAT3 signaling pathway for antitumor therapy. In the docking model, the quinazoline template of 5k, the lead compound, occupied a hydrophobic region such as Leu856, Leu855, Ala880, Leu932 and Gly935, and the highly conserved hydrogen bond was created by 6-OMe of the ring template, which binds to the NH of Arg980. Moreover, hydrophobic interactions were identified between morpholine moiety and the hydrophobic region formed by Leu855, Ala880, Tyr931, Val911 and Met929. Also, compound 5k more strongly inhibited JAK2 phosphorylation in mouse embryonic stem cells than AG490. Our study shows the successful application of virtual screening for lead discovery and we propose that the novel compound 5p can be an effective JAK2 inhibitor candidate for further antitumor agent research.

Structure-based Virtual Screening and Identification of a Novel Androgen Receptor Antagonist

Background: The androgen receptor (AR) is the primary drug target for prostate cancer treatment. Results: We have identified a novel AR antagonist, the compound 6-(3,4-dihydro-1H-isoquinolin-2-yl)-N-(6-methylpyridin-2-yl)nicotinamide (DIMN) that inhibits the growth of AR-positive prostate cancer cells. Conclusion: DIMN has been identified as a new lead structure targeting the AR. Significance: This novel AR antagonist could be a useful therapeutic agent for prostate cancer treatment. Hormonal therapies, mainly combinations of anti-androgens and androgen deprivation, have been the mainstay treatment for advanced prostate cancer because the androgen-androgen receptor (AR) system plays a pivotal role in the development and progression of prostate cancers. However, the emergence of androgen resistance, largely due to inefficient anti-hormone action, limits the therapeutic usefulness of these therapies. Here, we report that 6-(3,4-dihydro-1H-isoquinolin-2-yl)-N-(6-methylpyridin-2-yl)nicotinamide (DIMN) acts as a novel anti-androgenic compound that may be effective in the treatment of both androgen-dependent and androgen-independent prostate cancers. Through AR structure-based virtual screening using the FlexX docking model, fifty-four compounds were selected and further screened for AR antagonism via cell-based tests. One compound, DIMN, showed an antagonistic effect specific to AR with comparable potency to that of the classical AR antagonists, hydroxyflutamide and bicalutamide. Consistent with their anti-androgenic activity, DIMN inhibited the growth of androgen-dependent LNCaP prostate cancer cells. Interestingly, the compound also suppressed the growth of androgen-independent C4–2 and CWR22rv prostate cancer cells, which express a functional AR, but did not suppress the growth of the AR-negative prostate cancer cells PPC-1, DU145, and R3327-AT3.1. Taken together, the results suggest that the synthetic compound DIMN is a novel anti-androgen and strong candidate for useful therapeutic agent against early stage to advanced prostate cancer.

Synthesis, in vitro and in vivo evaluation of 3-arylisoquinolinamines as potent antitumor agents

In the search for potent water-soluble 3-arylisoquinolines, several 3-arylisoquinolinamines were designed and synthesized. Various substituted 3-arylisoquinolinamines exhibited strong cytotoxic activity against eight different human cancer cell lines. In particular, C-6 or C-7 dimethylamino-substituted 3-arylisoquinolinamines displayed stronger potency than the lead compound 7a. Interestingly, compounds 7b and 7c showed more effective activity against paclitaxel-resistant HCT-15 human colorectal cancer cell lines when compared to the original cytotoxic cancer drug, paclitaxel. We analyzed the cell cycle dynamics by flow cytometry and found that treatment of human HCT-15 cells with 3-arylisoquinolinamine 7b blocked or delayed the progression of cells from G0/G1 phase into S phase, and induced cell death. Treatment with compound 7b also significantly inhibited the growth of tumors and enhanced tumor regression in a paclitaxel-resistant HCT-15 xenograft model.

Relation between high-sensitivity C-reactive protein and coronary plaque components in patients with acute coronary syndrome: virtual histology-intravascular ultrasound analysis.

Background and Objectives We used virtual histology-intravascular ultrasound (VH-IVUS) to evaluate the relationship between high-sensitivity C-reactive protein (hs-CRP) levels and plaque components in 279 acute coronary syndrome (ACS) patients. Subjects and Methods We divided patients into three groups according to their hs-CRP levels {lowest tertile <0.07 mg/dL (n=93), middle tertile ≥0.07, <0.4 mg/dL (n=93), and highest tertile ≥0.4 mg/dL (n=93)}. Thin-cap fibroatheroma (TCFA) was defined as focal, necrotic core (NC)-rich (≥10% of the cross-sectional area) plaques in contact with the lumen in a plaque burden ≥40%. Results The highest tertile group was mostly diabetics (20%, 27%, 40%, p=0.009), and had the greatest plaque plus media volume (163±139/mm3 vs. 201±155/mm3 vs. 232±176/mm3, p=0.013). The highest tertile group had the greatest absolute and % NC volumes (13.6±15.1 mm3 vs. 14.8±14.2 mm3 vs. 23.7±24.3 mm3, p<0.001, and 14.9±8.7% vs. 16.0±8.7% vs. 19.5±10.2%, p=0.024, respectively). The culprit lesion TCFA was observed most frequently in the highest tertile group (28% vs. 35% vs. 55%, p=0.006). By multivariable analysis, absolute NC volume was an independent predictor of hs-CRP elevation {odds ratio (OR); 1.03, 95% confidence interval (CI)=1.06-1.21, p=0.004}, and hs-CRP was an independent predictor of TCFA (OR; 1.86, 95% CI=1.11-2.90, p=0.010). Conclusion VH-IVUS analysis has demonstrated that ACS patients with elevated hs-CRP have more vulnerable plaque component (NC-rich plaques and higher frequency of culprit lesion TCFA), compared with ACS patients with normal hs-CRP.

Synthesis of benzo[3,4]azepino[1,2-b]isoquinolin-9-ones from 3-arylisoquinolines via ring closing metathesis and evaluation of topoisomerase I inhibitory activity, cytotoxicity and docking study

Benzo[3,4]azepino[1,2-b]isoquinolinones were designed and developed as constraint forms of 3-arylisquinolines with an aim to inhibit topoisomerase I (topo I). Ring closing metathesis (RCM) of 3-arylisoquinolines with suitable diene moiety provided seven membered azepine rings of benzoazepinoisoquinolinones. Spectral analyses of these heterocyclic compounds demonstrated that the methylene protons of the azepine rings are nonequivalent. The shielding environment experienced by these geminal hydrogens differs unusually by 2.21ppm. As expected, benzoazepinoisoquinolinones displayed potent cytotoxicity. However, cytotoxic effects of the compounds were not related to topo I inhibition which is explained by non-planar conformation of the rigid compounds incapable of intercalating between DNA base pairs. In contrast, flexible 3-arylisoquinoline 8d attains active conformation at drug target site to exhibit topo I inhibition identical to cytotoxic alkaloid, camptothecin (CPT).

Design and synthesis of 4-amino-2-phenylquinazolines as novel topoisomerase I inhibitors with molecular modeling

4-Amino-2-phenylquinazolines 7 were designed as bioisosteres of 3-arylisoquinolinamines 6 that were energy minimized to provide stable conformers. Interestingly, the 2-phenyl ring of 4-amino-2-phenylquinazolines was parallel to the quinazoline ring and improved their DNA intercalation ability in the DNA-topo I complex. Among the synthesized 4-amino group-substituted analogs, 4-cyclohexylamino-2-phenylquinazoline 7h exhibited potent topo I inhibitory activity and strong cytotoxicity. Interestingly, consistency was observed between the cytotoxicities and topo I activities in these quinazoline analogs, suggesting that the target of 4-amino-2-phenylquinazolines is limited to topo I. Molecular docking studies were performed with the Surflex-Dock program to afford the ideal interaction mode of the compound into the binding site of the DNA-topo I complex in order to clarify the topo I activity of 7h.

Development of 3-aryl-1-isoquinolinamines as potent antitumor agents based on CoMFA

Various substituted 3-aryl-1-isoquinolinamines were designed and synthesized based on the previously constructed CoMFA model. Most of the synthesized compounds showed excellent potency in eight different human tumor cell lines as expected. In order to find the exact cytotoxic mechanism of these 3-aryl-1-isoquinolinamines, we analyzed the cell cycle dynamics by flow cytometry and found that 3-aryl-1-isoquinolinamine 6k-treated HeLa cells were arrested in G2/M phase, which is related to apoptosis.

Design, synthesis and docking study of 5-amino substituted indeno[1,2-c]isoquinolines as novel topoisomerase I inhibitors.

Various 5-amino group-substituted indeno[1,2-c]isoquinolines 7a-f were synthesized based on the previous QSAR study as rigid structures of 3-arylisoquinolines. Amino group-substituted compounds, especially 5-piperazinyl indeno[1,2-c]isoquinoline 7f, displayed potent topoisomerase I inhibitory activity as well as cytotoxicities against five different tumor cell lines. A Surflex-Dock docking model of 7f was also studied.

Images in cardiovascular medicine. Leiomyosarcoma involving main and left pulmonary artery treated surgically with homograft replacement and concomitant left pneumonectomy.

A 47-year-old woman presented with progressive dyspnea on exertion and generalized weakness for 6 months. On physical examination, a grade-III ejection systolic murmur was heard on her upper sternal border. Her chest x-ray showed mild cardiomegaly with multiple, variable-sized nodular opacities in the right lung (Figure 1). Echocardiography revealed severe supravalvular pulmonary stenosis (peak and mean pressure gradient 76 mm Hg and 45.6 mm Hg, respectively) due to diffuse tubular supravalvular stenosis associated with increased right ventricular pressure (93.9 mm Hg) and left pulmonary artery narrowing. Multislice computed tomogram showed an intravascular mass lesion at the suprapulmonic valvular area, narrowing the lumen and extending …