IND-2, a Quinoline Derivative, Inhibits the Proliferation of Prostate Cancer Cells by Inducing Oxidative Stress, Apoptosis and Inhibiting Topoisomerase II

In men, prostate cancer (PC) is the most frequently diagnosed cancer, causing an estimated 375,000 deaths globally. Currently, existing therapies for the treatment of PC, notably metastatic cases, have limited efficacy due to drug resistance and problematic adverse effects. Therefore, it is imperative to discover and develop novel drugs for treating PC that are efficacious and do not produce intolerable adverse or toxic effects. Condensed quinolines are naturally occurring anticancer compounds. In this study, we determined the in vitro efficacy of IND-2 (4-chloro-2-methylpyrimido[1″,2″:1,5]pyrazolo[3,4-b]quinolone) in the PC lines, PC-3 and DU-145. IND-2 significantly inhibited the proliferation of PC-3 and DU-145, with IC₅₀ values of 3 µM and 3.5 µM, respectively. The incubation of PC-3 cells with 5 and 10 µM of IND-2 caused the loss of the mitochondrial membrane potential in PC-3 cells. Furthermore, IND-2, at 5 µM, increased the expression of cleaved caspase-3, cleaved caspase-7 and cleaved poly (ADP-ribose) polymerase (PARP). The incubation of PC-3 cells with 5 µM of IND-2 significantly decreased the expression of the apoptotic protein, B-cell lymphoma 2 (Bcl-2). Furthermore, 5 and 10 µM of IND-2 produced morphological changes in PC-3 cells characteristic of apoptosis. Interestingly, IND-2 (2.5, 5 and 10 µM) also induced mitotic catastrophe in PC-3 cells, characterized by the accumulation of multinuclei. The incubation of DU-145 cells with 1.25 and 5 μM of IND-2 significantly increased the levels of reactive oxygen species (ROS). Finally, IND-2, at 10 μM, inhibited the catalytic activity of topoisomerase IIα. Overall, our findings suggest that IND-2 could be a potential lead compound for the development of more efficacious compounds for the treatment of PC.

Autophagic and apoptotic cell death induced by the quinoline derivative 2-(6-methoxynaphthalen-2-yl)quinolin-4-amine in pancreatic cancer cells is via ER stress and inhibition of Akt/mTOR signaling pathway

Pancreatic cancer (PC) is among the most lethal cancers and is resistant to existing therapies, which highlights the need for new and alternative therapeutic treatments. Autophagy is emerging as one of the alternative cell death mechanisms and is well known to cross-talk with apoptosis. Autophagy can act as a viable option to treat highly resistant PC. The current study investigates and provides insight into the autophagic and apoptotic cell death induced by quinoline derivative 2-(6-methoxynaphthalen-2-yl)quinolin-4-amine (6MN-4-AQ) in PC cell lines PANC-1 and MIA PaCa-2. Treatment with 6MN-4-AQ reduced cell viability in concentration dependent manner (2-16 μM) and inhibited the clonogenic potential of PC cells at a concentration of 4 μM for 24 h. Further, we found that 6MN-4-AQ induced both apoptosis and autophagic cell death simultaneously. We identified that 6MN-4-AQ induced autophagic cell death by forming cytoplasmic vacuoles, the elevation of autophagy flux, increase in LC3-II, Beclin-1 protein expression, and degradation of p62. Moreover, 6MN-4-AQ induced apoptosis via Caspase-3 activation and cleavage of PARP in PC cells. Upon investigating the underlying mechanism associated with 6MN-4-AQ induced cell death, it was observed that 6MN-4-AQ treatment is able to suppress the Akt/mTOR pathway and induced ER stress leading to the induction of autophagy. Also, 6MN-4-AQ treatment suppressed epithelial to mesenchymal transition by reducing the protein expression of SLUG, snail, and vimentin. Subsequently, 6MN-4-AQ inhibited cell migration and invasion by down regulating MMP-7 and MMP-9 protein expression, suggesting that 6MN-4-AQ may serve as a plausible therapeutic agent for PC.

Ex vivo potential of a quinoline-derivative nail lacquer as a new alternative for dermatophytic onychomycosis treatment

Introduction. Onychomycosis infections currently show a significant increase, affecting about 10 % of the world population. Trichophyton rubrum is the main agent responsible for about 80 % of the reported infections. The clinical cure for onychomycosis is extremely difficult and effective new antifungal therapy is needed.Hypothesis/Gap Statement. Ex vivo onychomycosis models using porcine hooves can be an excellent alternative for evaluating the efficacy of new anti-dermatophytic agents in a nail lacquer.Aim. Evaluation of the effectiveness of a nail lacquer containing a quinoline derivative on an ex vivo onychomycosis model using porcine hooves, as well as the proposal of a plausible antifungal mechanism of this derivative against dermatophytic strains.Methodology. The action mechanism of a quinoline derivative was evaluated through the sorbitol protection assay, exogenous ergosterol binding, and the determination of the dose-response curves by time-kill assay. Scanning electron microscopy evaluated the effect of the derivative in the fungal cells. The efficacy of a quinoline-derivative nail lacquer on an ex vivo onychomycosis model using porcine hooves was evaluated as well.Results. The quinoline derivative showed a time-dependent fungicidal effect, demonstrating reduction and damage in the morphology of dermatophytic hyphae. In addition, the ex vivo onychomycosis model was effective in the establishment of infection by T. rubrum.Conclusion. Treatment with the quinoline-derivative lacquer showed a significant inhibitory effect on T. rubrum strain in this infection model. Finally, the compound presents high potential for application in a formulation such as nail lacquer as a possible treatment for dermatophytic onychomycosis.

DFIQ, a Novel Quinoline Derivative, Shows Anticancer Potential by Inducing Apoptosis and Autophagy in NSCLC Cell and In Vivo Zebrafish Xenograft Models

Lung cancer is one of the deadliest cancers worldwide due to chemoresistance in patients with late-stage disease. Quinoline derivatives show biological activity against HIV, malaria, bacteriuria, and cancer. DFIQ is a novel synthetic quinoline derivative that induces cell death in both in vitro and in vivo zebrafish xenograft models. DFIQ induced cell death, including apoptosis, and the IC₅₀ values were 4.16 and 2.31 μM at 24 and 48 h, respectively. DFIQ was also found to induce apoptotic protein cleavage and DNA damage, reduce cell cycle-associated protein expression, and disrupt reactive oxygen species (ROS) reduction, thus resulting in the accumulation of superoxide radicals. Autophagy is also a necessary process associated with chemotherapy-induced cell death. Lysosome accumulation and lysosome-associated membrane protein-2 (LAMP2) depletion were observed after DFIQ treatment, and cell death induction was restored upon treatment with the autophagy inhibitor 3-methyladenine (3-MA). Nevertheless, ROS production was found to be involved in DFIQ-induced autophagy activation and LAMP2 depletion. Our data provide the first evidence for developing DFIQ for clinical usage and show the regulatory mechanism by which DFIQ affects ROS, autophagy, and apoptosis.

In vitro antitumor activity of TAS-103, a novel quinoline derivative that targets topoisomerases I and II

TAS-103 is a novel anticancer agent targeting both topoisomerase (Topo) I and Topo II, that stabilizes cleavable complexes of Topo-DNA at the cellular level. In this study, the in vitro antitumor effects of TAS-103 were compared with those of other known Topo I and Topo II inhibitors. TAS-103 inhibited DNA synthesis more strongly than RNA and protein synthesis, and induced an increase of cell population in the S-G2/M phase. The cytotoxicity of TAS-103 was strongest against S-phase cells, but its cell cycle phase specificity was not clear, and depended on drug concentration and exposure time. The cytotoxicity of TAS-103 (IC50: 0.0030-0.23 microM) against various tumor cell lines was much stronger than that of VP-16 and comparable to that of SN-38. The cytotoxicity of TAS-103 seemed to be more related to the amount of protein-DNA complexes than to the accumulation of TAS-103 in the cells. P-Glycoprotein (P-gp)-mediated MDR, CDDP-resistant and 5-FU-resistant cell lines did not show cross-resistance to TAS-103. Although PC-7/CPT cells bearing a Topo I gene mutation showed cross-resistance to TAS-103, the sensitivity of P388/CPT, HT-29/CPT and St-4/CPT cells, showing decreased Topo I expression, was not changed. KB/VM4 and HT-29/Etp cells, showing decreased Topo II expression, were slightly cross-resistant to TAS-103. These results suggest that TAS-103 may act as an inhibitor of both Topo I and Topo II at the cellular level. This property may be responsible for its strong antitumor effect and broad-spectrum, growth-inhibitory effect on drug-resistant cell lines.

Antitumor activity of a novel quinoline derivative, TAS-103, with inhibitory effects on topoisomerases I and II

A novel quinoline derivative, TAS-103 (6-[[2-(dimethylamino)ethyl]amino]-3-hydroxy-7H-indeno[2,1-c]quinolin -7-one dihydrochloride), was developed as an anticancer agent targeting topoisomerases (topo) I and II, with marked efficacy in solid tumors. TAS-103 inhibited topo I and II (IC50: 2 microM, 6.5 microM) at a concentration similar to or lower than those of previous agents, and had a strong cytotoxic effect on P388 and KB cells (IC50: 0.0011 microM, 0.0096 microM). TAS-103 stabilized topo I and II-DNA cleavable complexes in KB cells, generating a similar amount of topo II-DNA complex to that induced by etoposide (VP-16) but a smaller amount of topo I-DNA complex than that produced by camptothecin (CPT). In the in vivo study, intermittent i.v. administration was markedly effective against s.c.-implanted murine tumors. Furthermore, TAS-103 had marked efficacy against various lung metastatic tumors, and a broad antitumor spectrum in human tumor xenografts (derived from lung, colon, stomach, breast, and pancreatic cancer). The efficacy of TAS-103 was generally greater than that of irinotecan (CPT-11), VP-16, or cis-diamminedichloroplatinum (CDDP).