Structure-activity relationship and apoptosis induction in A549 cells by the potential anticancer compound cis-bis(3-aminoflavone)dichloroplatinum(II).

cis-DDP (cis-diamminedichloroplatinum(II), CAS 15663-27-1) is widely used in chemotherapy of many types of cancer. However, besides effectiveness, it gives many side effects which limit its clinical application. Therefore, nowadays studies are focused on searching for novel analogs of cis-DDP, at least equally effective in chemotherapy but less toxic. One of them might be cis-BAFDP (cis-bis(3-aminoflavone)dichloroplatinum(II)) with one of the hydrogen atoms of the amino group of cis-DDP replaced by a flavone ring. 3-Aminoflavone (AF) which posseses the desired NH2 group has been used as non-leaving ligand. The complex has been obtained in the reaction of AF and K2PtCl4. There are no data concerning evaluation of structural studies of cis-BAFDP, the beneficial anticancer properties of which were proved in vitro and in vivo. Therefore it was worthwhile to undertake a confirmation of the chemical structure of this compound by applying various spectroscopic techniques especially because of its potential pharmacological application. With this aim in mind this compound was characterized by: IR, 1H NMR, 195Pt NMR, UV absorption and fluorescence spectroscopy. Moreover, stronger apoptosis induction by cis-BAFDP than cis-DDP in the human nonsmall cancer cell line A549 was observed using Hoechst 33258/propidium iodide double staining.

Modulation of ethoxyquin genotoxicity by free radical scavengers and DNA damage repair in human lymphocytes.

N-tert-butyl-alpha-phenylnitrone (PBN) and its new derivative N-(Pyridine-4-ylmethylidene)-2-carboxy-tert-butylamine N-oxide (PBNC) were synthesized and used to modulate ethoxyquin (1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline, EQ) genotoxicity. Ethoxyquin, an antioxidant used mainly as a preservative in animal feeds, was shown to cause DNA breaks in human lymphocytes. The aim of the study was to evaluate the involvement of free radicals in the genotoxicity of EQ and its modulation by cellular repair systems. Human lymphocytes treated with EQ (10-50 microM) and nitrone free radical scavengers (100 microM) were tested with the comet assay. It was shown that both PBN and PBNC reduced the level of EQ-induced DNA damage, but PBN was slightly more effective. The modulation of the level of DNA damage was also observed as a result of DNA repair by cellular repair systems. Moreover, induction of oxidized bases by ethoxyquin was showed; lymphocytes exposed to ethoxyquin and treated with endonuclease III (Endo III) and formamidopyrimidine-DNA glycosylase (FpG), enzymes recognizing oxidized bases, displayed greater extent of DNA damage than those not treated with the enzymes.

Clastogenic and mitodepressive effects of the insecticide dichlorvos on root meristems of Vicia faba.

Plant bioassays are an important and integral part of the test battery used in detecting genotoxic/carcinogenic contamination in the environment. Highly sensitive biomonitoring of plant models have been developed, which enables the detection of hazards arising from pesticides, insecticides, industrial contamination, heavy metals and radiation. Root tips of Vicia faba ssp. minor were treated with 1-60 mM of the organophosphorus insecticide dichlorvos (DDVP) for 2 h, followed by a 20-h recovery period. Maleic acid hydrazide (MH) was used as a positive control for the mitotic index, micronucleus and chromosomal aberration assays performed on the Vicia model system. All treatments with DDVP significantly decreased the mitotic activity and increased the frequency of chromosomal aberrations at the metaphase. The frequency of micronuclei was significantly increased at DDVP concentrations starting from 10 mM. The results demonstrate clastogenic and mitodepressive effects of DDVP on Vicia faba cells.

Genotoxicity of novel trans-platinum(II) complex with diethyl (pyridin-4-ylmethyl)phosphate in human non-small cell lung cancer cells A549.

The dynamic development of metal-containing anticancer drugs has started since the discovery of cis-diamminedichloroplatinum(II). For many years it was believed that trans platinum(II) compounds were non-active as antitumour agents because trans-diamminedichloroplatinum is biologically inactive although it binds to DNA and also forms monoadducts and cross-links. In the present work the ability of a novel platinum(II) compound trans-[PtCl(2)(4-pmOpe)(2)] to induce DNA damage in human non-small cell lung cancer cells A549 was examined using the alkaline comet assay. The obtained results revealed that the novel trans platinum(II) complex induced DNA strand breaks, which were effectively repaired during 2h of post-incubation, and cross-links which remained unrepaired under these test conditions. Apart from that, the modified comet assay with incubation with proteinase K was used to verify the ability of trans-[PtCl(2)(4-pmOpe)(2)] and cis-DDP to form DNA-protein cross-links. It has been proved that only trans-[PtCl(2)(4-pmOpe)(2)] complex exhibits the ability to induce DNA-protein cross-links. The results suggest a different mechanism of action of this compound in comparison to cis-DDP. It seems that trans geometry and the presence of two diethyl (pyridin-4-ylmethyl)phosphates as non-leaving ligands can determine dissimilar properties of the adducts formed on DNA and the different mechanism of action of trans-[PtCl(2)(4-pmOpe)(2)] and in consequence the efficacy in killing cancer cells.

Evaluation of P53 and BAX gene expression and induction of apoptosis and necrosis by the cis-Pt(II) complex of 3-aminoflavone in comparison with cis-diamminedichloroplatinum(II) (cis-DDP) in human lymphocytes.

Currently cis-diamminedichloroplatinum(II) (cis-DDP) is one of the most commonly applied compounds in chemotherapy of many types of cancer. However, a drawback is that its effectiveness presents with many side effects. Therefore, human normal lymphocytes were chosen as a model system to study cis-bis(3-aminoflavone)dichloroplatinum(II) (the cis-Pt(II) complex of 3-aminoflavone) in comparison with cis-DDP. We examined the effect of both tested compounds on cell viability and induction of apoptosis and necrosis. Trypan blue and acridine orange/ethidium bromide staining were carried out, as well as quantitative analysis of the apoptotic signal of P53 and BAX induction caused by the cis-Pt(II) complex of 3-aminoflavone in comparison with cis-DDP. cis-DDP induced a decrease of cell viability and led to a higher increase in necrosis and apoptosis than did the cis-Pt(II) complex of 3-aminoflavone. Moreover, at the molecular level cis-DDP increased P53 and BAX expression in comparison with the other tested compound. The cis-Pt(II) complex of 3-aminoflavone showed a weaker genotoxic effect in normal lymphocytes in comparison with cis-DDP, which was a stronger inducer of apoptosis and necrosis.

Synthesis, spectroscopy and antiproliferative activity of cis- and trans-platinum(II) complexes with diethyl (pyridin-4-ylmethyl)phosphate. X-ray crystal structure of trans-Pt(II) complex.

Preparations of cis- and trans-platinum(II) complexes of diethyl (pyridin-4-ylmethyl)phosphate (4-pmOpe) have been described. These complexes were identified and characterized by far-IR, 1H NMR, 13C NMR, 31P NMR and 195Pt NMR and microanalyses. The crystal and molecular structure of trans-platinum(II) complex i.e., trans-[PtCl2(4-pmOpe)2] was determined by the X-ray diffraction. Novel complexes were assayed for their potential antiproliferative effect against HT 29 (colorectal adenocarcinoma) and A 549 (non-small cell lung cancer) cell lines as well as normal human peripheral blood lymphocytes. The results obtained indicate that novel analogues of cis-diamminedichloroplatinum(II) cause inhibition of cells growth which suggest that they could be chemotherapeutic drugs in the future.

Enhanced P53 and BAX gene expression and apoptosis in A549 cells by cis-Pt(II) complex of 3-aminoflavone in comparison with cis-DDP.

Lung cancer remains one of the most common causes of cancer-related death worldwide. Approximately 80% is histologically non-small cell lung carcinoma (NSCLC) and in about 70% of patients it is an unresectable type. Clinical studies indicated that application of platinum derivatives caused good results and combinations of platinum with other agents could improve median survivals. In view of the central problem of sufficient efficiency of drugs in chemotherapy, efforts have focused on the development of alternative platinum-based analogues that can be more effective in cancer treatment. cis-bis(3-aminoflavone)dichloroplatinum(II) (cis-Pt(II) complex of 3-aminoflavone) represents a novel class of platinum-based potential antitumour agents. In order to evaluate the degree of apoptosis, acridine orange/ethidium bromide and Hoechst 33258/propidum iodide double staining as well as RT-PCR (P53 and BAX expression evaluation) were used in lung cancer cell line A549 after treatment with this compound in comparison with cis-diamminedichloroplatinum(II) (cis-DDP). Apoptotic cells at early and late stages and also necrotic ones were observed after usage of cis-Pt(II) complex of 3-aminoflavone and the percentage of these cells outnumbered the values obtained after cis-DDP application. The former compound induced a higher percentage of P53 and BAX expression in A549 cells in comparison with the latter one. Results indicate the beneficial properties of cis-Pt(II) complex of 3-aminoflavone as a potential antitumor drug.

Electrochemical genosensing of the interaction between the potential chemotherapeutic agent, cis-bis(3-aminoflavone)dichloroplatinum(II) and DNA in comparison with cis-DDP.

The interaction of cis-diamminedichloroplatinum(II) (cis-DDP) and the potential novel chemotherapeutic agent, cis-bis(3-aminoflavone)dichloroplatinum(II) (cis-BAFDP) was studied electrochemically with calf thymus double-stranded DNA (dsDNA) by using differential pulse voltammetry (DPV) with disposable pencil graphite electrode (PGE) at the surface. These studies were prompted by beneficial biological properties of cis-BAFDP in comparison with cis-DDP, which were proven in vitro both in human normal and cancer cells and in vivo. The changes in the experimental parameters such as the concentration of cis-DDP and cis-BAFDP were studied by using DPV; in addition, the reproducibility of this genosensor and the detection limit for each compound were determined. After the interaction of cis-DDP with dsDNA, the DPV signal of guanine and adenine was found to be decreasing. In comparison with cis-DDP, a dramatic decrease at adenine signal was also obtained after the interaction of cis-BAFDP and dsDNA. Similar results were also found in solution phase after the latter compound interacts with poly[A]. The features of the proposed electrochemical method for the detection of cis-BAFDP with DNA in comparison with cis-DDP are discussed and compared with those methods previously reported for the other type of DNA-targeted agents in the literature.

Induction of apoptosis and necrosis in A549 cells by the cis-Pt(II) complex of 3-aminoflavone in comparison with cis-DDP.

Non-small cell lung cancer (NSCLC) includes a group of tumors that respond poorly to drugs. cis-Diamminedichloroplatinum(II) (cis-DDP) toxicity still remains problematic, and not completely solved by the improvement of supportive care. Therefore, the cis-Pt(II) complex of 3-aminoflavone was selected from cis-DDP analogues with a more favourable toxic profile towards normal cells and at least similar or better anti-tumor activity in comparison with cis-DDP. The aim of this research is to compare the ability of the cis-Pt(II) complex of 3-aminoflavone and cis-DDP to induce apoptosis and necrosis in the human non-small cancer cell line A549. Trypan blue dye exclusion, fluorochrome staining (acridine orange/ethidium bromide double staining), MTT and TUNEL (TdT-mediated dUTP Nick-End Labeling) assays were used. The results obtained show that the cis-Pt(II) complex of 3-aminoflavone is more active in inducing apoptosis and necrosis and in decreasing viability in A549 cells than cis-DDP, which suggests that it could be a potential chemotherapeutic drug.

Genotoxicity of cis-PtII complex of 3-aminoflavone in comparison with cis-DDP in A549 cells evaluated by comet assay.

Cis-diamminedichloroplatinum(II) (cis-DDP) is one of the most successful antineoplastic drugs. However, besides effectiveness it gives many side effects. Therefore, current studies are concentrated on searching for new analogs equally effective in chemotherapy but less toxic. Comparison of genotoxic properties of cis-Pt(II) complex of 3-aminoflavone and cis-DDP in a comet assay with and without H2O2 application was performed in A549 cell line. The higher tail moment values were noticed for the former compound contrary to the latter one in both variants. It suggests mainly DNA breaks (besides cross-links) appearance after cis-Pt(II) complex of 3-aminoflavone application and might indicate DNA degradation in comparison with cis-DDP.

Evaluation of the genotoxicity of cis-bis(3-aminoflavone)dichloroplatinum(II) in comparison with cis-DDP.

Short-term tests that detect genetic damage have provided information needed for evaluating carcinogenic risks of chemicals to man. The mutagenicity of cis-bis(3-aminoflavone)dichloroplatinum(II) (cis-[Pt(AF)2Cl2]) in comparison with cis-diamminedichloroplatinum(II) (cis-DDP) was evaluated in the standard plate-incorporation assay in four strains of Salmonella typhimurium: TA97a, TA98, TA100 and TA102, in experiments with and without metabolic activation. It was shown that cis-[Pt(AF)2Cl2] acts directly and is mutagenic for three strains of S. typhimurium: TA97a, TA98 and TA100. In comparison with cis-DDP this compound showed a weaker genotoxicity. Contrary to cis-DDP it has not shown toxic properties in the tester bacteria. The genotoxicity of both tested compounds was evaluated using chromosomal aberration, sister chromatid exchange and micronucleus assays, without and with metabolic activation, in human lymphocytes in vitro. The inhibitory effects of both compounds on mitotic activity, cell proliferation kinetics and nuclear division index were also compared. In all test systems applied, cis-[Pt(AF)2Cl2] was a less effective clastogen and a weaker inducer of both sister chromatid exchanges and micronuclei in comparison with cis-DDP, with and without metabolic activation. cis-[Pt(AF)2Cl2] has a direct mechanism of action and is less cytostatic and cytotoxic than the other compound. These results provide important data on the genotoxicity of cis-[Pt(AF)2Cl2] and indicate its beneficial properties as a potential anticancer drug, especially in comparison with cis-DDP.

Induction of apoptosis and necrosis in lymphocytes by the cis-Pt(II) complex of 3-aminoflavone in comparison with cis-DDP.

cis-Diamminedichloroplatinum(II) (cis-DDP) is one of the most widely administrated antitumor drugs. However, the use of cis-DDP is severely limited because of its toxic side effects. Therefore, efforts are concentrated on the development of improved platinum compounds with a broader activity spectrum and effectiveness in chemotherapy, but lower toxicity. Beneficial properties of flavonoids, e.g. their antitumor activity, encouraged scientists to synthesize cis-bis(3-aminoflavone)dichloroplatinum(II). Abilities of these compounds to induce apoptosis and necrosis were compared by use of trypan blue, fluorochrome staining (Hoechst 33258/propidium iodide double staining) and TUNEL assays. The cytotoxicity was evaluated by MTT. The results obtained show that the cis-Pt(II) complex of 3-aminoflavone is less toxic than cis-DDP. However, the former compound has a faster rate of apoptosis induction in lymphocytes than the latter. The cis-Pt(II) complex of 3-aminoflavone induces apoptosis in normal lymphocytes to a lesser degree and could be a potential antitumor drug.