9-Phenyl acridine exhibits antitumour activity by inducing apoptosis in A375 cells

Acridine as an Anti-Tumour Agent: A Critical Review

This review summarized the current breakthroughs in the chemistry of acridines as anti-cancer agents, including new structural and biologically active acridine attributes. Acridine derivatives are a class of compounds that are being extensively researched as potential anti-cancer drugs. Acridines are well-known for their high cytotoxic activity; however, their clinical application is restricted or even excluded as a result of side effects. The photocytotoxicity of propyl acridine acts against leukaemia cell lines, with C1748 being a promising anti-tumour drug against UDP-UGT's. CK0403 is reported in breast cancer treatment and is more potent than CK0402 against estrogen receptor-negative HER2. Acridine platinum (Pt) complexes have shown specificity on the evaluated DNA sequences; 9-anilinoacridine core, which intercalates DNA, and a methyl triazene DNA-methylating moiety were also studied. Acridine thiourea gold and acridinone derivatives act against cell lines such as MDA-MB-231, SK-BR-3, and MCF-7. Benzimidazole acridine compounds demonstrated cytotoxic activity against Dual Topo and PARP-1. Quinacrine, thiazacridine, and azacridine are reported as anti-cancer agents, which have been reported in the previous decade and were addressed in this review article.

Bystander effect of ultraviolet A radiation protects A375 melanoma cells by induction of antioxidant defense

Ultraviolet (UV) irradiated cells release factors that result in varied responses by non-irradiated cells via bystander effects (BE). The UV-BE is dependent on the cell types involved and on the wavelength of the radiation. Using conditioned medium from UVA-irradiated A375 human melanoma cells (UVA-CM), UVA-bystander response was evaluated on the viability of naïve A375 cells. UVA-CM treatment itself did not alter cell viability; however, UVA-CM treated bystander cells were more resistant to the lethal action of UVA, UVB, UVC or H₂O₂. Effects of UVA-CM on cell proliferation, mechanism of cell death, DNA damage, malondialdehyde formation, generation of reactive oxygen species (ROS) and antioxidant status were studied in A375 cells. We observed that UVA-CM triggered antioxidant defenses to elicit protective responses through elevation of antioxidant enzyme activities in cells, which persisted until 5 h after exposure to UVA-CM. This was possibly responsible for decreased generation of ROS and diminished DNA and membrane damage in cells. These bystander cells were resistant to killing when exposed to different genotoxic agents. Damaged nuclei, induction of apoptosis and autophagic death were also lowered in these cells. The influence of UVA-CM on cancer stem cells side population was assessed.Highlights:UVA radiation induced bystander effects in A375 cellsDamage by genotoxicants is suppressed due to lower ROS generation on UVA-CM treatmentUVA-CM exposure enhanced higher activities of CAT and GPxResistance to genotoxic agents in such cells was due to elevated antioxidant defenceUVA-bystander phenomenon was a protective response.

Ameliorative effects of 9-diaminoacridine derivative against Ehrlich ascites carcinoma-induced hepatorenal injury in mice

Ehrlich ascites carcinoma induces hepatorenal injuries while acridine derivatives have antioxidant, anticancer, and anti-inflammatory. Thus, this study evaluated the protective potential of a newly synthesized the 9-diaminoacridine derivative (9-DAAD), N1-(acridin-9-yl) propane-1, 3-diamine hydrochloride, against Ehrlich ascites carcinoma (EAC) induced hepatorenal injury in female mice. Forty female mice were allocated into 4 groups. Group I was injected with 0.1% DMSO subcutaneously and kept a control. Group II received 9-DAAD (30 mg/kg bw/2 days) subcutaneously for 2 weeks. Group III was injected interaperitonealy with 2.5 × 106 cells of EAC/20 g bw. Group IV was injected with EAC as the third group and administered with 9-DAAD as the second group for 2 weeks after induction of EAC. EAC significantly elevated total leukocytes and platelets counts; activities of serum AST, ALT, and ALP; serum levels of alpha-fetoprotein; carcinoembryonic antigen; urea and creatinine; and expression of vascular endothelial growth factor protein in hepatic and renal tissues. Meanwhile it decreased red blood cells count, hemoglobin concentration and hematocrit value. At the same time, it significantly reduced serum levels of total protein and albumin and altered hepatic and renal tissues structures. Also, EAC decreased apoptosis and DNA synthesis in hepatic and renal cells. However, treatment of EAC-bearing mice with 9-DAAD improved liver and kidney structures, functions and modulated EAC altered parameters, as well as it reduced hepatic and renal cells proliferation and DNA synthesis. This study indicated that 9-DAAD had a potential ameliorative effect against EAC-induced hepatorenal injury.

Studies to explore the UVA photosensitizing action of 9-phenylacridine in cells by interaction with DNA

Acridine and its derivatives are well known for their DNA binding properties. In this report, we present our findings on evaluating different binding parameters of the interaction of 9-phenylacridine (ACPH) with DNA. Absorption spectroscopic studies including standard and reverse titration, the effects of ionic strength and temperature on titration, and Job plot analysis were done to calculate the binding constant and determine the different thermodynamic parameters and stoichiometry of the binding. Spectrofluorimetry and circular dichroism (CD) spectral titration were also utilized to confirm these findings. The results indicated that ACPH binds to DNA reversibly through non-electrostatic interactions by hydrogen bonding and van der Waals interactions. The binding constant and the number of binding sites were of the order 10³ M^-1 and ≈2, respectively with a binding stoichiometry of 1:4. The binding of ACPH with DNA was spontaneous, exothermic and enthalpy-driven. The extent of uptake of ACPH in B16 melanoma cells was estimated. As this compound absorbs in the UVA region, the effect of treatment with ACPH prior to UVA exposure was assessed to evaluate its phototoxicity in these cells. Our results indicated that the binding to DNA enhanced damage to sensitize cells to killing through apoptosis. Our findings indicated its potential to act as a photosensitizer.

Synthesis and evaluation of new compounds bearing 3-(4-aminopiperidin-1-yl)methyl magnolol scaffold as anticancer agents for the treatment of non-small cell lung cancer via targeting autophagy

Magnolol and honokiol are the two major active ingredients with similar structure and anticancer activity from traditional Chinese medicine Magnolia officinalis, and honokiol is now in a phase I clinical trial (CTR20170822) for advanced non-small cell lung cancer (NSCLC). In search of potent lead compounds with better activity, our previous study has demonstrated that magnolol derivative C2, 3-(4-aminopiperidin-1-yl)methyl magnolol, has better activity than honokiol. Here, based on the core of 3-(4-aminopiperidin-1-yl)methyl magnolol, we synthesized fifty-one magnolol derivatives. Among them, compound 30 exhibited the most potent antiproliferative activities on H460, HCC827, H1975 cell lines with the IC50 values of 0.63-0.93 μM, which were approximately 10- and 100-fold more potent than those of C2 and magnolol, respectively. Besides, oral administration of 30 and C2 on an H460 xenograft model also demonstrated that 30 has better activity than C2. Mechanism study revealed that 30 induced G0/G1 phase cell cycle arrest, apoptosis and autophagy in cancer cells. Moreover, blocking autophagy by the autophagic inhibitor enhanced the anticancer activity of 30in vitro and in vivo, suggesting autophagy played a cytoprotective role on 30-induced cancer cell death. Taken together, our study implied that compound 30 combined with autophagic inhibitor could be another choice for NSCLC treatment in further investigation.

9-phenyl acridine photosensitizes A375 cells to UVA radiation

Acridines are an important class of bioactive molecules having varied uses. Its derivative, 9-phenylacridine (ACPH) had been found to exhibit antitumor activity both in cell lines and in vivo model. Its DNA binding ability and absorbance in the ultraviolet range encouraged us to investigate its role as a photosensitizer with UVA radiation. We investigated the effects of ACPH prior to UVA exposure on in vitro DNA through photo-cleavage assay. Effect of such treatment was also studied in cultured A375 melanoma cells. Endpoints studied included morphological changes, evaluation of cellular viability, scratch assay, intracellular reactive oxygen species (ROS) production, DNA damage, lipid peroxidation, glutathione (GSH) level, autophagy, cell cycle progression, depletion of mitochondrial membrane potential (ΔΨmt), induction of apoptosis and Hoechst dye efflux assay. Our findings indicated that ACPH could sensitize damage to DNA induced by UVA both in vitro and in cells. It could also potentiate cell killing by UVA. It arrested cells in G2/M phase and induced apoptotic death through mitochondria mediated pathway. This sensitization was through enhancement of intracellular ROS. Our findings also indicated that the stem cells side population was reduced on such treatment. The findings are important as it indicates ACPH as a promising photosensitizer and indicates its possible role in photodynamic therapy.

Novel 1,4-dihydropyridine induces apoptosis in human cancer cells through overexpression of Sirtuin1

1,4-Dihydropyridines (1,4-DHPs) are important as a class of heterocyclic compounds that exhibit wide range of biological actions. Many of its derivatives are already characterized as medicinally important drugs and used worldwide. In this study, we have screened some novel Hantzsch 1,4-DHP compounds using both in silico (QSAR and Pharmacophore) and in vitro (cytotoxic screening). 1,4-DHP showed selective cytotoxicity against five human cancerous cell lines; A375, A549, HeLa, HepG2 and SH-SY5Y but limited effect towards normal skin keratinocyte (HaCaT), lung fibroblast (WL-38) and healthy peripheral blood mononuclear cells. In A375 and HepG2 cells, one of the 1,4-DHP derivative (DHP-8) was found to inhibit cell proliferation, and simultaneously increased the apoptotic population as well as mitochondrial membrane depolarization. Furthermore, the mitochondrial signal was triggered with the activation of cleaved Caspase9, Caspase3 and PARP. The treatment with DHP-8 also increased the expression level of SIRT1, subsequently decreasing the level of pAKT^ser473 and survivin. Reduced pAKT^ser473 expression led to decrease the phosphorylated inactive form of GSK3β^ser9 and as a result, proteasomal degradation of Mcl-1 occurred in both the cell lines. Here, we suggest that the apoptotic effect of DHP-8 in A375 and HepG2 cells was mediated by AKT and survivin pathways through SIRT1 activation. The involvement of DHP-8 in SIRT1 activation was further verified by co-treatment of nicotinamide with DHP-8 in both A375 and HepG2 cells. Overall, this study emphasizes the possible potential and therapeutic role of DHP-8 in skin and liver cancer.

1,3-dimethyl-6-nitroacridine derivatives induce apoptosis in human breast cancer cells by targeting DNA

The acridine derivatives can interact with the double-stranded DNA, which is regarded as the biological target of the anticancer drugs in cancer treatment. We designed and synthesized a new series of 1,3-dimethyl-6-nitroacridine derivatives as potential DNA-targeted anticancer agents. These compounds could partially intercalate into the calf thymus DNA, differing from the parent acridine. The results showed that the substitutions of the acridine ring had great effect on DNA binding affinity. The binding constants determined by UV-vis spectroscopy were found to be 10⁵ M^-1 grade. Anticancer activity of these compounds was screened using MTT assay. Most compounds inhibited 50% cancer cell growth at concentration below 30 μM, the results were consistent with the DNA binding ability. Compounds 1 and 6 were found to have more effective cytotoxicity, especially in human breast cancer cell lines. To investigate the action mechanism, we studied cell apoptosis, morphological changes, and cell cycle distribution in MCF-7 and MDA-MB-231 cells. Compounds 1 and 6 caused MCF-7 and MDA-MB-231 cells death due to apoptosis, and induced cell apoptosis in a dose-dependent manner. They also had significant effect on cell cycle progression and arrested cell cycle at G2/M phase. The results demonstrated that compounds 1 and 6 are promising candidates for cancer treatment.

Discovery and synthesis of novel magnolol derivatives with potent anticancer activity in non-small cell lung cancer

EGFR T790 M accounts for 50% to 60% of cases of non-small-cell lung carcinoma (NSCLC) resistance to the first-generation EGFR tyrosine kinase inhibitors (TKIs). Hence, identifying novel compounds with activity against TKIs resistant is of great value. In this study, twenty honokiol and magnolol derivatives were isolated from the EtOH extract of Magnolia officinalis and the antiproliferative activity was evaluated on HCC827 (19del EGFR mutation), H1975 (L858 R/T790 M EGFR mutation), and H460 (KRAS mutation) cell lines. Among the isolated compounds, piperitylmagnolol (a 3-substituted magnolol derivative) showed the best antiproliferative activity against those three cell lines with the IC₅₀ values of 15.85, 15.60 and 18.60 μM, respectively, which provided a direction for the structural modification of magnolol. Further structural modification led to the synthesis of thirty-one magnolol derivatives, and compounds A13, C1, and C2 exhibited significant and broad-spectrum antiproliferative activity with the IC₅₀ values ranging from 4.81 to 13.54 μM, which were approximately 4- and 8-fold more potent than those of honokiol and magnolol, respectively. Moreover, their aqueous solubility was remarkably improved with 12-, 400- and 10⁵ fold greater than those of honokiol and magnolol. Anti-tumor mechanism research revealed that these three compounds were able to induce cell cycle arrest at G0/G1 phase, cause efficient apoptosis in H1975 cells, and also prevent the migration of HUVECs in a dose-dependent manner through Cdk2, Cdk4, Cyclin E, and Cyclin D1 inhibition as well as up-regulation of cleaved-PARP and cleaved-caspase 3 levels. In in vivo antitumor activity, C2 (10, 30 and 100 mg/kg, po) dose-dependently inhibited the tumor growth in H1975 xenograft model with the tumor inhibition rate of 46.3%, 59.3% and 61.2% respectively, suggesting that C2 is a potential oral anticancer agent deserving further investigation.

3-Nitroacridine derivatives arrest cell cycle at G0/G1 phase and induce apoptosis in human breast cancer cells may act as DNA-target anticancer agents

DNA is considered to be one of the most promising targets for anticancer agents. Acridine analogues have anticancer activity based on DNA binding and topoisomerases inhibition. However, due to the side effects, resistance and low bioavailability, a few have entered into clinical usage and the mechanisms of action are not fully understood. Novel acridine derivatives are needed for effective cancer therapy. A series of novel 3-nitroacridine-based derivatives were synthesized, their DNA binding and anticancer activities were evaluated. The chemical modifications at position 9 of the 3-nitroacridine were crucial for DNA affinity, thus optimizing anticancer activity. UV-Vis and circular dichroism (CD) spectroscopy indicated interaction of compounds with DNA, and the binding modes were intercalation and groove binding. MTT assay and clonogenic assay showed that compounds 1, 2 and 3 had obvious cell growth inhibition effect. They induced cell apoptosis in human breast cancer cells in a dose-dependent manner, and exhibited anticancer effect via DNA damage as well as cell cycle arrest at G0/G1 phage. Using confocal fluorescent microscope, the apoptotic features were observed. The results suggested that compounds 1-3 with high DNA binding affinity and good inhibitory effect of cancer cell proliferation can be developed as prime candidates for further chemical optimization.

INHIBITION OF PACLITAXEL AGAINST NEUROGLIOMA CELLS U251 GROWTH AND ITS MECHANISM

Background:

Glioma is the most common primary tumor of the central nervous system, and accounted for about 70% of primary tumors.

Materials and Methods:

In the study, antitumour activity and mechanism of paclitaxel was investigated. Different concentrations of paclitaxel (200, 300, 400 μmol/L) was treated in neuroglioma cellsU251.

Results:

Paclitaxel significantly inhibited neuroglioma cells growth, and promoted its apoptosis. Paclitaxel can block tumour cells in the G2/M phase. In addition, apoptosis-related genes caspase-3 and bax expressions were increased after paclitaxel treatment.

Conclusion:

Our work indicated that paclitaxel displayed strong anti-tumour activity.

Novel tetrahydroacridine and cyclopentaquinoline derivatives with fluorobenzoic acid moiety induce cell cycle arrest and apoptosis in lung cancer cells by activation of DNA damage signaling

Lung cancer is still the leading cause of cancer-related death worldwide, indicating a necessity to develop more effective therapy. Acridine derivatives are potential anticancer agents due to their ability to intercalate DNA as well as inhibit enzymes involved in replication and transcription. Recently, we have evaluated anticancer activity of 32 novel acridine-based compounds. We found that the most effective were tetrahydroacridine and cyclopentaquinoline derivatives with fluorobenzoic acid containing eight and nine carbon atoms in the aliphatic chain. The aim of this study was to determine the molecular mechanisms of compounds-induced cell cycle arrest and apoptosis in human lung adenocarcinoma cells. All compounds activated Ataxia telangiectasia mutated kinase and phosphorylated histone H2A.X at Ser139 indicating DNA damage. Treatment of cells with the compounds increased phosphorylation and accumulation of p53 that regulate cell cycle as well as apoptosis. All compounds induced G0/1 cell cycle arrest by phosphorylation of cyclin-dependent kinase 2 at Tyr15 resulting in attenuation of the kinase activity. In addition, cyclopentaquinoline derivatives induced expression of cyclin-dependent kinase 2 inhibitor, p21; however, tetrahydroacridine derivatives had no significant effect on p21. Moreover, all compounds decreased the mitochondrial membrane potential accompanied by increased expression of Bax and down-regulation of Bcl-2, suggesting activation of the mitochondrial pathway. All compounds also significantly attenuated the migration rates of lung cancer cells. Collectively, our findings suggest a central role of activation of DNA damage signaling in response to new acridine derivatives treatment to induce cell cycle arrest and apoptosis in cancer cells and provide support for their further development as potential drug candidates.

Direct detection of the anti-cancer drug 9-phenylacridine in tissues by graphite rod laser desorption vacuum-ultraviolet post-ionization mass spectrometry

RATIONALE

Traditionally, drug analysis in biological tissue by mass spectrometry has required complicated sample pre-treatment, which not only wasted time, but also had adverse effects on the results. In order to assist assessment of potential drugs rapidly and accurately, a direct analytical method for drug detection in tissues is needed. The development of such a method is described in this study.

METHODS

An anti-cancer drug, 9-phenylacridine (ACPH), injected into the kidney of mice, was directly analysed from tissues placed on the surface of a graphite rod by near-infrared (1064 nm) laser desorption single photon ionization mass spectrometry (LD/SPI-MS).

RESULTS

The LD/SPI-MS method was successfully validated by direct analysis of ACPH in kidney sections of mice, without any complicated and time-consuming sample pre-treatment. The sensitivity of detection was down to about 100 fmol per spot and the wide linear dynamic range allowed quantitative detection of ACPH in complex biological samples. A drug-time curve was acquired of ACPH in the kidney of mice after the drug had been injected into the caudal vein.

CONCLUSIONS

It was demonstrated that the anti-tumor drug ACPH could be directly and rapidly detected by LD/SPI-MS in biological tissues without any time-consuming pre-treatment procedure. This method could potentially be applied to the selective localization and analysis of small molecule drugs in tissues and to the study of the pharmacokinetics of new drugs.

Novel tetrahydroacridine derivatives inhibit human lung adenocarcinoma cell growth by inducing G1 phase cell cycle arrest and apoptosis

Lung cancer is not only the most commonly diagnosed cancers worldwide but it is still the leading cause of cancer-related death. Acridine derivatives are a class of anticancer agents with the ability to intercalate DNA and inhibit topoisomerases. The aim of this study was to evaluate the effect of sixteen new tetrahydroacridine derivatives on the viability and growth of human lung adenocarcinoma cells. We compared anticancer activity of a series of eight compounds with 4-fluorobenzoic acid and eight compounds with 6-hydrazinonicotnic acid differed from each other in length of the aliphatic chain containing from 2 to 9 carbon atoms. Interestingly, tetrahydroacridine with 4-fluorobenzoic acid (compounds 9-16) showed higher anticancer activity than derivatives with 6-hydrazinonicotnic acid (compounds 1-8) and their efficacy was correlated with increasing number of carbon atoms in the aliphatic chain. The results showed that inhibition of cancer cell growth by the most effective compounds 15 and 16 was associated with induction of G1 phase cell cycle arrest followed by caspase-3 dependent apoptosis. Our findings suggest that tetrahydroacridine with 4-fluorobenzoic acid containing 8 and 9 carbon atoms may be potential candidate for treatment of lung cancer.

New cyclopentaquinoline derivatives with fluorobenzoic acid induce G1 arrest and apoptosis in human lung adenocarcinoma cells

Non-small cell lung cancer accounts for 80-85% of all lung cancer cases and is the leading cause of cancer death indicating inefficient current treatment. Acridine derivatives interact with DNA and inhibit topoisomerase leading to cell growth arrest or cell death. The aim of this study was to evaluate the effects of new synthesized sixteen 2,3-dihydro-1H-cyclopenta[b]quinoline derivatives (cyclopentaquinoline), a member of acridine-based compounds, on the survival and growth of human lung adenocarcinoma, A549 cells. Anticancer activity of eight new cyclopentaquinoline derivatives with hydrazinonicotinic acid (compounds 1-8) and eight with fluorobenzoic acid (compounds 9-16) were screened using WST-1 assay. Interestingly, cyclopentaquinoline derivatives with fluorobenzoic moiety were found to have a higher anticancer activity than derivatives with hydrazinonicotinic acid. Four out of eight tested compounds with fluorobenzoic acid inhibited 50% cancer cell growth at concentration below 20μM. Moreover, the efficacy of cyclopentaquinoline derivatives containing fluorobenzoic acid correlated with increasing number of carbon atoms in the aliphatic chain. The most effective compounds (6, 15, 16) were selected to determine molecular mechanisms of their anticancer action. The results indicated that inhibition of A549 cell growth by compounds 15 and 16 was associated with a cell cycle arrest at G0/1 phase and with induction of caspase 3-dependent apoptosis. Compound 6 also caused A549 cells death due to apoptosis, however, it had no significant effect on a cell cycle progression. These findings suggest that cyclopentaquinoline derivatives containing fluorobenzoic acid with 8 and 9 carbon atoms in aliphatic chain may be promising candidate for treatment of lung cancer.

Antioxidant enzymes and the mechanism of the bystander effect induced by ultraviolet C irradiation of A375 human melanoma cells

Irradiated cells generate dynamic responses in non-irradiated cells; this signaling phenomenon is known as the bystander effect (BE). Factors secreted by the irradiated cells communicate some of these signals. Conditioned medium from UVC-irradiated A375 human melanoma cells was used to study the BE. Exposure of cells to conditioned medium induce cell-cycle arrest at the G2/M transition. Although conditioned medium treatment, by itself, did not alter cell viability, treated cells were more resistant to the lethal action of UVC or H2O2. This protective effect of conditioned medium was lost within 8h. Apoptotic or autophagic cell death was not involved in this resistance. Exposure to conditioned medium did not influence the rate of DNA repair, as measured by NAD(+) depletion. The activities of catalase and superoxide dismutase were elevated in cells exposed to conditioned medium, but returned to normal levels by 8h post-treatment. These results indicate a close correlation between BE-stimulated antioxidant activity and cellular sensitivity. Cell-cycle arrest and stimulation of antioxidant activity may account for the resistance to killing that was observed in bystander cells exposed to UVC or H2O2 treatment and are consistent with the role of the BE as a natural defense function triggered by UVC irradiation.