Acridine derivatives as inhibitors/poisons of topoisomerase II

In vitro detection of cancer cells using a novel fluorescent choline derivative

INTRODUCTION

The treatment of preinvasive lesions is more effective than treating invasive disease, hence detecting cancer at its early stages is crucial. However, currently, available screening methods show various limitations in terms of sensitivity, specificity, and practicality, thus novel markers complementing traditional cyto/histopathological assessments are needed. Alteration in choline metabolism is a hallmark of many malignancies, including cervical and breast cancers. Choline radiotracers are widely used for imaging purposes, even though many risks are associated with their radioactivity. Therefore, this work aimed to synthesise and characterise a non-radioactive choline tracer based on a fluorinated acridine scaffold (CFA) for the in vitro detection of cervical and breast cancer cells by fluorescence imaging.

METHODS

CFA was fully characterised and tested for its cytotoxicity on breast (MCF-7), cervical (HeLa), glioblastoma (U-87 MG) and hepatoblastoma (HepG2) cancer cell lines and in normal cell lines (epithelial, HEK-293 and human dermal fibroblasts, HDFs). The cellular uptake of CFA was investigated by a confocal microscope and its accumulation was quantified over time. The specificity of CFA over mesenchymal origin cells (HDFs), as a model of cancer-associated fibroblasts was investigated by fluorescence microscopy.

RESULTS

CFA was toxic at much higher concentrations (HeLa IC50 = 200 ± 18 µM and MCF-7 IC50 = 105 ± 3 µM) than needed for its detection in cancer cells (5 µM). CFA was not toxic in the other cell lines tested. The intensity of CFA in breast and cervical cancer cells was not significantly different at any time point, yet it was greater than HepG2 and U-87 MG (p ≤ 0.01 and p ≤ 0.0001, respectively) after 24 h incubation. A very weak signal intensity was recorded in HEK-293 and HDFs (p ≤ 0.001 and p ≤ 0.0001, respectively). A selective ability of CFA to accumulate in HeLa and MCF-7 was recorded upon co-culture with fibroblasts.

CONCLUSIONS

The results showed that CFA preferentially accumulated in cancer cells rather than in normal cells. These findings suggest that CFA may be a potential diagnostic probe for discriminating healthy tissues from malignant tissues due to its specific and highly sensitive features; CFA may also represent a useful tool for in vitro/ex vivo investigations of choline metabolism in patients with cervical and breast cancers.

In Silico and In Vitro Investigation of Cytotoxicity and Apoptosis of Acridine/Sulfonamide Hybrids Targeting Topoisomerases I and II

BACKGROUND

Sulfonamide acridine derivatives have garnered significant attention from medicinal chemists due to their diverse range of biological activities.

METHODS

In this study, eleven compounds were synthesized according to the literature, and their impact on cell growth inhibition, induction of apoptosis, and cell cycle distribution were assessed in three different cell lines. Their inhibitory effects on the topoisomerase (Topo) I and II were investigated in vitro. Molecular docking studies were conducted to predict the binding affinities of these compounds for crystallized downloaded topoisomerases.

RESULTS

The compounds were examined in vitro for their anticancer activity against human hepatic (HepG2) colon (HCT-8) and breast (MCF-7) carcinoma cell lines. Compound 8b was the most active against HepG2, HCT-116, and MCF-7 with IC50 14.51, 9.39, and 8.83 µM, respectively, compared to Doxorubicin as reference. In addition, it demonstrated the highest potency among the tested compounds against Topo-I, with an IC50 value of 3.41 µg/mL compared to the control camptothecin (IC50 of 1.46 μM). Compound 7c displayed a significant inhibitory effect on Topo-II, with an IC50 of 7.33 μM, compared to an IC50 value of 6.49 μM via Doxorubicin, the control. Compounds 7c and 8b were assessed against topoisomerases showing induction of apoptosis and a reduction in the S phase of the cell cycle. Molecular docking demonstrated interaction with the active site as with those exhibited by the co-crystallized ligands of the crystallized proteins in both topoisomerases.

CONCLUSION

Compounds 7c and 8b hold promise as potential anticancer drugs due to their anti-proliferative and proapoptotic effects, which are mediated by their action on the topoisomerase enzyme, particularly Topo II.

Recent Advances in the Synthesis and Optical Applications of Acridine-based Hybrid Fluorescent Dyes

Acridine-based hybrid fluorescent dyes represent a category of dyes that integrate the acridine chromophore with other functional groups or materials to enhance their fluorescence properties. These dyes have garnered substantial attention across various domains, encompassing bioimaging, sensing, and optoelectronics. In recent years, researchers have directed their efforts toward fabricating acridine-based hybrid fluorescent dyes with improved water solubility, biocompatibility, and targeting capabilities. These advancements have facilitated their utilization in biological imaging applications, such as monitoring cellular processes, investigating protein-protein interactions, and detecting specific biomolecules. This review delineates the recent progress in synthesizing acridine-based hybrid fluorescent dyes and their applications in optical properties over the past decade. This review is anticipated to catalyze the development of innovative fluorescent materials featuring heightened properties and functionalities.

Research status and prospects of organic photocatalysts in algal inhibition and sterilization: a review

An increasing amount of sewage has been discharged into water bodies in the progression of industrialization and urbanization, causing serious water pollution. Meanwhile, the increase of nutrients in the water induces water eutrophication and rapid growth of algae. Photocatalysis is a common technique for algal inhibition and sterilization. To improve the utilization of visible light and the conversion efficiency of solar energy, more organic photocatalytic materials have been gradually developed. In addition to ultraviolet light, partial infrared light and visible light could also be used by organic photocatalysts compared with inorganic photocatalysts. Simultaneously, organic photocatalysts also exhibit favorable stability. Most organic photocatalysts can maintain a high degradation rate for algae and bacteria after several cycles. There are various organic semiconductors, mainly including small organic molecules, such as perylene diimide (PDI), porphyrin (TCPP), and new carbon materials (fullerene (C60), graphene (GO), and carbon nanotubes (CNT)), and large organic polymers, such as graphite phase carbon nitride (g-C3N4), polypyrrole (PPy), polythiophene (PTH), polyaniline (PANI), and polyimide (PI). In this review, the classification and synthesis methods of organic photocatalytic materials were elucidated. It was demonstrated that the full visible spectral response (400-750 nm) could be stimulated by modifying organic photocatalysts. Moreover, some problems were summarized based on the research status related to algae and bacteria, and corresponding suggestions were also provided for the development of organic photocatalytic materials.

Mechanistic study of dual-function inhibitors targeting topoisomerase II and Rad51-mediated DNA repair pathway against castration-resistant prostate cancer

BACKGROUND

Castration-resistant prostate cancer (CRPC) is refractory to hormone treatment and the therapeutic options are continuously advancing. This study aims to discover the anti-CRPC effects and underlying mechanisms of small-molecule compounds targeting topoisomerase (TOP) II and cellular components of DNA damage repair.

METHODS

Cell proliferation was determined in CRPC PC-3 and DU-145 cells using anchorage-dependent colony formation, sulforhodamine B assay and flow cytometric analysis of CFSE staining. Flow cytometric analyses of propidium iodide staining and JC-1 staining were used to examine the population of cell-cycle phases and mitochondrial membrane potential, respectively. Nuclear extraction was performed to detect the nuclear localization of cellular components in DNA repair pathways. Protein expressions were determined using Western blot analysis.

RESULTS

A series of azathioxanthone-based derivatives were synthesized and examined for bioactivities in which WC-A13, WC-A14, WC-A15, and WC-A16 displayed potent anti-CRPC activities in both PC-3 and DU-145 cell models. These WC-A compounds selectively downregulated both TOP IIα and TOP IIβ but not TOP I protein expression. WC-A13, WC-A14, and WC-A15 were more potent than WC-A16 on TOP II inhibition, mitochondrial dysfunction, and induction of caspase cascades indicating the key role of amine-containing side chain of the compounds in determining anti-CRPC activities. Furthermore, WC-A compounds induced an increase of γH2AX and activated ATR-Chk1 and ATM-Chk2 signaling pathways. P21 protein expression was also upregulated by WC-A compounds in which WC-A16 showed the least activity. Notably, WC-A compounds exhibited different regulation on Rad51, a major protein in homologous recombination of DNA in double-stranded break repair. WC-A13, WC-A14, and WC-A15 inhibited, whereas WC-A16 induced, the nuclear translocation of Rad51.

CONCLUSION

The data suggest that WC-A compounds exhibit anti-CRPC effects through the inhibition of TOP II activities, leading to mitochondrial stress-involved caspase activation and apoptosis. Moreover, WC-A13, WC-A14, and WC-A15 but not WC-A16 display inhibitory activities of Rad51-mediated DNA repair pathway which may increase apoptotic effect of CRPC cells.

Acridine/Acridone-Carborane Conjugates as Strong DNA-Binding Agents with Anticancer Potential

Synthesis of acridine derivatives that act as DNA-targeting anticancer agents is an evolving field and has resulted in the introduction of several drugs into clinical trials. Carboranes can be of importance in designing biologically active compounds due to their specific properties. Therefore, a series of novel acridine analogs modified with carborane clusters were synthesized. The DNA-binding ability of these analogs was evaluated on calf thymus DNA (ct-DNA). Results of these analyses showed that 9-[(1,7-dicarba-closo-dodecaborane-1-yl)propylamino]acridine (30) interacted strongly with ct-DNA, indicating its ability to intercalate into DNA, whereas 9-[(1,7-dicarba-closo-dodecaborane-1-yl)propanamido]acridine (29) changed the B-form of ct-DNA to the Z form. Compound 30 demonstrated cytotoxicity, was able to inhibit cell proliferation, arrest the cell cycle in the S phase in the HeLa cancer cell line, and induced the production of reactive oxygen species (ROS). In addition, it was specifically localized in lysosomes and was a weak inhibitor of Topo IIα.

Chalcone-Acridine Hybrid Suppresses Melanoma Cell Progression via G2/M Cell Cycle Arrest, DNA Damage, Apoptosis, and Modulation of MAP Kinases Activity

This study was focused on investigating the antiproliferative effects of chalcone hybrids in melanoma cancer cells. Among seven chalcone hybrids, the chalcone-acridine hybrid 1C was the most potent and was selected for further antiproliferative mechanism studies. This in vitro study revealed the potent antiproliferative effect of 1C via cell cycle arrest and apoptosis induction. Cell cycle arrest at the G2/M phase was associated with modulation of expression or phosphorylation of specific cell cycle-associated proteins (cyclin B1, p21, and ChK1), tubulins, as well as with the activation of the DNA damage response pathway. Chalcone 1C also induced apoptosis accompanied by mitochondrial dysfunction evidenced by a decrease in mitochondrial membrane potential, increase in Bax/Bcl-xL ratio and cytochrome c release followed by caspase 3/7 activation. In addition, increased phosphorylation of MAP kinases (Erk1/2, p38 and JNK) was observed in chalcone 1C-treated melanoma cells. The strong antiproliferative activities of this chalcone-acridine hybrid suggest that it may be useful as an antimelanoma agent in humans.

Acridine Based N-Acylhydrazone Derivatives as Potential Anticancer Agents: Synthesis, Characterization and ctDNA/HSA Spectroscopic Binding Properties

A series of novel acridine N-acylhydrazone derivatives have been synthesized as potential topoisomerase I/II inhibitors, and their binding (calf thymus DNA—ctDNA and human serum albumin—HSA) and biological activities as potential anticancer agents on proliferation of A549 and CCD-18Co have been evaluated. The acridine-DNA complex 3b (-F) displayed the highest Kb value (Kb = 3.18 × 103 M−1). The HSA-derivatives interactions were studied by fluorescence quenching spectra. This method was used for the calculation of characteristic binding parameters. In the presence of warfarin, the binding constant values were found to decrease (KSV = 2.26 M−1, Kb = 2.54 M−1), suggesting that derivative 3a could bind to HSA at Sudlow site I. The effect of tested derivatives on metabolic activity of A549 cells evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide or MTT assay decreased as follows 3b(-F) > 3a(-H) > 3c(-Cl) > 3d(-Br). The derivatives 3c and 3d in vitro act as potential dual inhibitors of hTopo I and II with a partial effect on the metabolic activity of cancer cells A594. The acridine-benzohydrazides 3a and 3c reduced the clonogenic ability of A549 cells by 72% or 74%, respectively. The general results of the study suggest that the novel compounds show potential for future development as anticancer agents.

Dual targeting, a new strategy for novel PARP inhibitor discovery

As a hallmark for cancer treatment, PARP inhibitors can effectively kill tumor cells with a mechanism termed as synthetic lethality, and are used to treat various cancers including ovarian, breast, prostate, pancreatic and others with DNA repair defects. However, along with the clinical trials progressing, the limitations of PARP-1 inhibitors became apparent such as limited activity and indications. Studies have shown that a molecule that is able to simultaneously restrict two or more targets involving in tumors is more effective in preventing and treating cancers due to the enhancing synergies. In order to make up for the shortcomings of PARP inhibitors, reduce the development cost and overcome the pharmacokinetic defects, multiple works were carried out to construct dual targeting PARP inhibitors for cancer therapy. Herein, they were summarized briefly.