Chih-Hua Tseng

Synthesis and antiproliferative evaluation of certain indeno[1 ,2-c]quinoline derivatives

Although the quinoline ring is found in a wide variety of biologically active compounds and is frequently condensed with various heterocycles, synthesis and biological evaluation of the indenoquinoline skeleton attracts only very limited attention. We report herein the synthesis and antiproliferative evaluation of certain indeno[1,2-c]quinoline derivatives against the growth of six cancer cell lines including human cervical epithelioid carcinoma (HeLa), oral squamous cell carcinoma (SAS), hepatocellular carcinoma (SKHep), human stomach adenocarcinoma (AGS), prostate cancer (PC-3), and non-small cell lung cancer (A549). The results indicated that 9-methoxy-6-(piperazin-1-yl)-11H-indeno[1,2-c]quinolin-11-one (17b) is more active than its C(6)-amino derivative 17a, C(6)-morpholine and C(6)-piperidine isomers, 17c and 17d, respectively. Treatment of 17b with NH(2)OH afforded its hydroxyimino derivative 20 which is more active than the carbonyl precursor 17b. More potent agents were obtained by further derivatization of 20. Thus, antiproliferative activities decreased in an order of aminoalkoxyimino 22a-d>hydroxyimino 20>alkoxyimino 21, 22e>carbonyl 17b. Both AGS and A549 were resistant to camptothecin with GI(50) values of 23.76 and 2.80 microM, respectively, while GI(50) values for 22a-d were in the range of 5.93-7.11 microM and 0.38-0.87 microM, respectively. Among them, 22b was the most potent with GI(50) values of 0.52, 0.74, 6.76, and 0.64 microM against the growth of HeLa, SKHep, AGS, and A549 cells, respectively. Flowcytometric analysis indicated 22c can induce cell cycle arrest in S phase, and DNA polyploidy (>4n) followed by apoptosis.

Synthesis and antiproliferative evaluation of certain indeno[1,2-c]quinoline derivatives. Part 2.

Certain indeno[1,2-c]quinoline derivatives were synthesized and evaluated for their antiproliferation, DNA binding affinity, and topoisomerases (topo I and topo II) inhibitory activities. The preliminary results are the following: (1) substituent of the aminoalkoxyimino side chain at C11 is important for antiproliferative activities in which the terminal amine preferred to be a tertiary or the cyclic five-membered pyrrolidino ring; (2) among the indeno[1,2-c]quinoline derivatives evaluated, (E)-6-hydroxy-9-methoxy-11H-indeno[1,2-c]quinolin-11-one O-2-(pyrrolidin-1-yl)ethyl oxime (8c) was found to be one of the most cytotoxic agents with a GI50 value of 0.84, 0.89, and 0.79 microM against SAS, A549, and BT483, respectively, which is more active than camptothecin; (3) substituent at C6 is crucial for the selective cytotoxicity in which the OH group is the most preferred while hydrogen or piperazine exhibited cytotoxicity on both cancer cells and Detroit-551; (4) a positive correlation of antiproliferative activity, DNA binding affinity, and topo I and topo II inhibitory activities has been observed for indeno[1,2-c]quinoline derivatives; (5) compound 8c induced DNA fragmentation may through caspase-3 activation, phosphorylation of the histone protein H2AX at Ser139 (gamma-H2AX), and PARP cleavage; (6) compound 8c demonstrated significant tumor regression in the human breast xenograft model; (7) indeno[1,2-c]quinoline derivatives are a new class of molecules that have the potential to be developed as dual topo I and topo II inhibitory agents.

p38 MAPK and NF-κB pathways are involved in naphtho[1,2-b] furan-4,5-dione induced anti-proliferation and apoptosis of human hepatoma cells

Naphtho[1,2-b] furan-4,5-dione (NFD) was investigated for its anti-proliferation effect on human hepatocellular carcinoma (HCC), Hep3B, HepG(2), and Huh-7 cells. The effect of NFD on inhibiting proliferation and apoptosis was correlated with up-regulation of pro-apoptotic protein and down-regulation of pro-survival proteins. Remarkably, we found that NFD inhibited the nuclear translocation of NF-kappaB, likely accounting for the down-regulation of pro-survival Bcl-2 family. Furthermore, suppression of p38 MAPK activity by a specific inhibitor significantly rescued the cell proliferation inhibited by NFD. These findings suggest that signaling imbalance between p38 MAPK and NF-kappaB by NFD results in the proliferative inhibition and apoptosis of HCC tumor cells.

Synthesis and antiproliferative evaluation of 6-arylindeno[1,2-c]quinoline derivatives

A number of 6-aryl-11-iminoindeno[1,2-c]quinoline derivatives were synthesized and evaluated for their antiproliferative activities. Among them, (E)-6-{4-[3-(dimethylamino)propoxy]phenyl}-2-fluoro-9-hydroxy-11H-indeno[1,2-c]quinolin-11-one O-3-(dimethylamino)propyl oxime (23a) was the most active, exhibited GI(50) values of 0.64, 0.39, 0.55, 0.67, and 0.65μM against the growth of Hep G2, Hep 3B, A549, H1299, and MDA-MB-231, respectively. Compound 23a inhibited the growth of hepatoma cell lines in a dose- and time-dependent manner. The proportion of cells was decreased in the G1 and accumulated in G2/M phase after 12h treatment of 23a, while the hypodiploid (sub-G0/G1 phase) cells increased. Further investigations have shown that 23a induced cell cycle arrest at G2/M phase and induce apoptosis via activation of p53, Bax, and caspase-8 which consequently cause cell death.

Naphtho[1,2-b]furan-4,5-dione induces apoptosis and S-phase arrest of MDA-MB-231 cells through JNK and ERK signaling activation.

Naphtho[1,2-b]furan-4,5-dione (NFD), prepared from 2-hydroxy-1,4-naphthoquinone and chloroacetaldehyde in an efficient one-pot reaction, exhibits anti-carcinogenic effect. The results of present study showed that NFD inhibited the proliferation of breast cancer MDA-MB-231 cells through the induction of S-phase arrest and apoptosis. NFD-induced S-phase arrest was associated with a marked decrease in the protein expression of cyclin A, cyclin B, and cyclin-dependent kinase (Cdk)2. NFD-induced apoptosis was characterized by increase of sub-G1 population, phosphatidylserine (PS) externalization, and activation of caspases. Moreover, up-regulation of Bad and down-regulation of Bcl-2, Bcl-X(L), and survivin led to the loss of mitochondrial membrane potential (DeltaPsim), the release of cytochrome c and sequential activation of caspase-9 and caspase-3. NFD activated c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (p38 MAPK) and extracellular signal-regulated kinase (ERK) in MDA-MB-231 cells. Inhibitors of JNK (SP600125) and ERK (PD98059), but not p38 MAPK (SB203580) suppressed NFD-induced S-phase arrest and apoptosis in MDA-MB-231 cells. Both SP600125 and PD98059 attenuated Bad up-regulation, and reversed down-regulation of Bcl-2, Bcl-X(L), survivin, cyclin A, cyclin B, and Cdk2 in NFD-treated cells. Taken together, our data show that JNK and ERK-signaling pathways play important roles in NFD-mediated S-phase arrest and apoptosis of MDA-MB-231 cells.

Identification of benzofuro[2,3-b]quinoline derivatives as a new class of antituberculosis agents.

A series of 11-alkoxylated and 11-aminated benzofuro[2,3-b]quinoline derivatives were designed, synthesized, and evaluated for their anti-TB and cytotoxic activities. The known 11-chlorobenzofuro[2,3-b]quinoline (3) was synthesized in a single step from anthranilic acid and 2-coumaranone in phosphorus oxychloride in 51% yield for the first time. Treatment of 3 with alcohols and amines gave 11-alkoxylated and 11-aminated benzofuro[2,3-b]quinoline derivatives respectively, which were evaluated for their anti-TB and cytotoxic activities. Our results indicated that 11-arylaminated derivatives were more active than their respective 11-aryloxylated isosteric isomers against Mycobacterium tuberculosis. Among the tested compounds, 11-methoxybenzofuro[2,3-b]quinoline (4), 11-methylamino- benzofuro[2,3-b]quinoline (9), and 11-dimethylaminobenzofuro[2,3-b]quinoline (14) exhibited significant activities against the growth of M. tuberculosis (MIC values of <0.20 microg/mL) and low cytotoxicities against VERO cell with IC(50) values of 11.77, 5.55, and >30.00 microg/mL respectively. The selectivity index (SI=IC(50)/MIC) for 4, 9, and 14 was greater than 58.85, 27.75, and 150 respectively.

Anti-hepatitis C virus activity of 3-hydroxy caruilignan C from Swietenia macrophylla stems.

Summary.  Chronic hepatitis C virus (HCV) infection ultimately leads to chronic hepatitis, hepatic cirrhosis and hepatocellular carcinoma (HCC). As the standard treatment is not completely efficacious, a safer and more effective agent against HCV infection needs to be developed. In this report, we demonstrated that 3‐hydroxy caruilignan C (3‐HCL‐C) isolated from Swietenia macrophylla stems exhibited high anti‐HCV activity at both protein and RNA levels at nontoxic concentrations, with an EC50 value of 10.5 ± 1.2 μm. Combinations of 3‐HCL‐C and interferon‐α (IFN‐α), an HCV NS5B polymerase inhibitor (2′‐C‐methylcytidine; NM‐107) or an HCV NS3/4A protease inhibitor (Telaprevir; VX‐950) increased the suppression of HCV RNA replication. The results suggested that 3‐HCL‐C may be a potential anti‐viral agent. We then demonstrated that 3‐HCL‐C interfered with HCV replication by inducing IFN‐stimulated response element transcription and IFN‐dependent anti‐viral gene expression.

Discovery of 4-Anilinofuro[2,3-b]quinoline Derivatives as Selective and Orally Active Compounds against Non-Small-Cell Lung Cancers

We have reported the preparation and anticancer evaluation of certain 4-anilinofuro[2,3-b]quinolines. However, drawbacks such as lack of selective cytotoxicity, poor oral bioavailability, and poor water solubility exhibited by these compounds prompted us to search for newer derivatives. Among them, (E)-1-(4-(furo[2,3-b]quinolin-4-ylamino)phenyl)ethanone O-2-aminoethyloxime (13a) is selectively active against the growth of NCI-H460 and is highly water-soluble (63 μg/mL). Its hydrochloride salt, 13a·HCl exhibited not only excellent water solubility (1049 μg/mL) but also a high oral bioavailability (57.1%). Compound 13a may cause cancer cell apoptosis through inducing mitotic arrest and mitotic catastrophe mechanism. Xenographic studies indicated the tumor size with 13a·HCl treated nude mice was significantly lower than control. Further evaluation in an orthotopic lung cancer model indicated that 13a·HCl can be absorbed readily through oral administration, distributed to lung tissue, and exhibited significant efficacy in inhibiting the growth of lung cancers.

Inhibition of EGF/EGFR activation with naphtho[1,2-b]furan-4,5-dione blocks migration and invasion of MDA-MB-231 cells.

Naphtho[1,2-b]furan-4,5-dione (NFD), a bioactive component of Avicennia marina, has been demonstrated to display anti-cancer activity. Activation of epidermal growth factor receptor (EGFR)-induced signaling pathway has been correlated with cancer metastasis in various tumors, including breast carcinoma. We use EGF as a metastatic inducer of MDA-MB-231 cells to investigate the effect of NFD on cell migration and invasion. NFD suppressed EGF-mediated protein levels of c-Jun and c-Fos, and reduced MMP-9 expression and activity, concomitantly with a marked inhibition on cell migration and invasion without obvious cellular cytotoxicity. NFD abrogated EGF-induced phosphorylation of EGF receptor (EGFR) and phosphatidylinositol 3-kinase (PI3K)/Akt. The specific PI3K inhibitor, wortmannin, blocked significantly EGF-induced cell migration and invasion. Furthermore, the EGFR inhibitor AG1478 inhibited EGF-induced MMP-9 expression, cell migration and invasion, as well as the activation of PI3K/Akt, suggesting that PI3K/Akt activation occur downstream of EGFR activation. These findings suggest that NFD inhibited the EGF-induced invasion and migration of MDA-MB-231 cells via EGFR-dependent PI3K/Akt signaling, leading to the down-regulation of MMP-9 expression. These results provide a novel mechanism to explain the role of NFD as a potent anti-metastatic agent in MDA-MB-231 cells.

San-Huang-Xie-Xin-Tang extract suppresses hepatitis C virus replication and virus-induced cyclooxygenase-2 expression.

Summary.  Chronic hepatitis C virus (HCV) infection is associated with chronic inflammation of liver, which leads to the development of cirrhosis and hepatocellular carcinoma (HCC). Because of severe side effects and only a 50–70% cure rate in genotype 1 HCV‐infected patients upon current standard treatment with pegylated interferon‐α plus ribavirin, new therapeutic regimens are still needed. San‐Huang‐Xie‐Xin‐Tang (SHXT) is a transitional Chinese herbal formula, composed of Rhei rhizoma, Scutellaria radix and Coptidis rhizome, and possesses anti‐inflammatory effect. Here, we describe a (+)‐catechin‐containing fraction extracted from SHXT, referred as SHXT‐frC, exhibited effective inhibition of HCV replication, with selectivity index value (SI; CC50/EC50) of 84, and displayed synergistic anti‐HCV effects when combined with interferon‐α, HCV protease inhibitor telaprevir or polymerase inhibitor 2′‐C‐methylcytidine. The activation of factor‐κB (NF‐κB) and cyclooxygenase‐2 (COX‐2) signalling pathway has particular relevance to HCV‐associated HCC. SHXT‐frC treatment also caused a concentration‐dependent decrease in the induction of COX‐2 and NF‐κB expression caused by either HCV replication or HCV NS5A protein. Collectively, SHXT‐frC could be an adjuvant treatment for patients with HCV‐induced liver diseases.