The role of reactive oxygen species in WP 631-induced death of human ovarian cancer cells: A comparison with the effect of doxorubicin

Catechin-Albumin Conjugates: Enhanced Antioxidant Capacity and Anticancer Effects

(+)-Catechin conjugated with human serum albumin (CT–HSA) was prepared and evaluated as a drug carrier bearing anticancer effects. It was found that 2.4 mol of CT was conjugate to 1 mol HSA. The CT–HSA has an antioxidant capacity of about 3.3 times the amount of CT in the conjugate. Intracellular incorporation of the CT–HSA was analyzed by fluorescence-activated cell sorting (FACS) and confocal laser scanning microscopy (CLSM) measurements using fluorescein isothiocyanate (FITC)-labelled CT–HSA. The results indicated that the FITC-labelled CT–HSA was incorporated into HeLa cells in a concentration-dependent manner. The CT–HSA enhanced the binding of anticancer drugs (5-fluorouracil (5-Fu) and mitomycin C (MMC)) comparing with HSA, and the CT–HSA mixed with 5-Fu or MMC decreased significantly the HeLa cell viability as compared with the same concentration of each drug. In addition, intracellular reactive oxygen species (ROS) scavenging by the CT–HSA is likely to affect the anticancer effects. Thus, the CT–HSA enhanced anticancer drug efficacy in relation to controlling ROS-scavenging ability.

Determination of Apoptotic Mechanism of Action of Tetrabromobisphenol A and Tetrabromobisphenol S in Human Peripheral Blood Mononuclear Cells: A Comparative Study

Background: Tetrabromobisphenol A (TBBPA) is the most commonly used brominated flame retardant (BFR) in the industry. TBBPA has been determined in environmental samples, food, tap water, dust as well as outdoor and indoor air and in the human body. Studies have also shown the toxic potential of this substance. In search of a better and less toxic BFR, tetrabromobisphenol S (TBBPS) has been developed in order to replace TBBPA in the industry. There is a lack of data on the toxic effects of TBBPS, while no study has explored apoptotic mechanism of action of TBBPA and TBBPS in human leukocytes. Methods: The cells were separated from leucocyte-platelet buffy coat and were incubated with studied compounds in concentrations ranging from 0.01 to 50 µg/mL for 24 h. In order to explore the apoptotic mechanism of action of tested BFRs, phosphatidylserine externalization at cellular membrane (the number of apoptotic cells), cytosolic calcium ion and transmembrane mitochondrial potential levels, caspase-8, -9 and -3 activation, as well as PARP-1 cleavage, DNA fragmentation and chromatin condensation in PBMCs were determined. Results: TBBPA and TBBPS triggered apoptosis in human PBMCs as they changed all tested parameters in the incubated cells. It was also observed that the mitochondrial pathway was mainly involved in the apoptotic action of studied compounds. Conclusions: It was found that TBBPS, and more strongly TBBPA, triggered apoptosis in human PBMCs. Generally, the mitochondrial pathway was involved in the apoptotic action of tested compounds; nevertheless, TBBPS more strongly than TBBPA caused intrinsic pathway activation.

Apoptosis-Inducing Potential of Selected Bromophenolic Flame Retardants 2,4,6-Tribromophenol and Pentabromophenol in Human Peripheral Blood Mononuclear Cells

(1) Background: 2,4,6-Tribromophenol (2,4,6-TBP) and pentabromophenol (PBP) are utilized as brominated flame retardants (BFRs) in order to reduce the combustion of materials used in various utility products. The presence of 2,4,6-TBP and PBP has been reported in environmental samples as well as in inhaled air, dust, food, drinking water, and the human body. To date, there are limited data concerning the toxic action of 2,4,6-TBP and particularly PBP, and no study has been conducted to assess the apoptotic mechanism of action of these substances in human leukocytes. (2) Methods: PBMCs were isolated from leukocyte–platelet buffy coat and treated with tested substances in concentrations ranging from 0.01 to 50 µg/mL for 24 h. The apoptotic mechanism of action of the tested BFRs was assessed by the determination of phosphatidylserine exposure on the PBMCs surface, the evaluation of mitochondrial potential and cytosolic calcium ion levels, and the determination of caspase-8, -9, and -3 activation. Moreover, poly (ADP-ribose) polymerase-1 (PARP-1) cleavage, DNA fragmentation, and chromatin condensation were analyzed. (3) Results: 2,4,6-TBP and, more strongly, PBP induced apoptosis in PBMCs, changing all tested parameters. It was also found that the mitochondrial pathway was mainly involved in the apoptosis of PBMCs exposed to the studied compounds. (4) Conclusions: 2,4,6-TBP and PBP triggered apoptosis in human PBMCs, and some observed changes occurred at 2,4,6-TBP concentrations that were detected in humans occupationally exposed to this substance.

Doxorubicin-loaded iron oxide nanoparticles for glioblastoma therapy: a combinational approach for enhanced delivery of nanoparticles

Although doxorubicin (DOX) is an effective anti-cancer drug with cytotoxicity in a variety of different tumors, its effectiveness in treating glioblastoma multiforme (GBM) is constrained by insufficient penetration across the blood–brain barrier (BBB). In this study, biocompatible magnetic iron oxide nanoparticles (IONPs) stabilized with trimethoxysilylpropyl-ethylenediamine triacetic acid (EDT) were developed as a carrier of DOX for GBM chemotherapy. The DOX-loaded EDT-IONPs (DOX-EDT-IONPs) released DOX within 4 days with the capability of an accelerated release in acidic microenvironments. The DOX-loaded EDT-IONPs (DOX-EDT-IONPs) demonstrated an efficient uptake in mouse brain-derived microvessel endothelial, bEnd.3, Madin–Darby canine kidney transfected with multi-drug resistant protein 1 (MDCK-MDR1), and human U251 GBM cells. The DOX-EDT-IONPs could augment DOX’s uptake in U251 cells by 2.8-fold and significantly inhibited U251 cell proliferation. Moreover, the DOX-EDT-IONPs were found to be effective in apoptotic-induced GBM cell death (over 90%) within 48 h of treatment. Gene expression studies revealed a significant downregulation of TOP II and Ku70, crucial enzymes for DNA repair and replication, as well as MiR-155 oncogene, concomitant with an upregulation of caspase 3 and tumor suppressors i.e., p53, MEG3 and GAS5, in U251 cells upon treatment with DOX-EDT-IONPs. An in vitro MDCK-MDR1-GBM co-culture model was used to assess the BBB permeability and anti-tumor activity of the DOX-EDT-IONPs and DOX treatments. While DOX-EDT-IONP showed improved permeability of DOX across MDCK-MDR1 monolayers compared to DOX alone, cytotoxicity in U251 cells was similar in both treatment groups. Using a cadherin binding peptide (ADTC5) to transiently open tight junctions, in combination with an external magnetic field, significantly enhanced both DOX-EDT-IONP permeability and cytotoxicity in the MDCK-MDR1-GBM co-culture model. Therefore, the combination of magnetic enhanced convective diffusion and the cadherin binding peptide for transiently opening the BBB tight junctions are expected to enhance the efficacy of GBM chemotherapy using the DOX-EDT-IONPs. In general, the developed approach enables the chemotherapeutic to overcome both BBB and multidrug resistance (MDR) glioma cells while providing site-specific magnetic targeting.

1,25‑Dihydroxyvitamin D3 enhances the susceptibility of anaplastic thyroid cancer cells to adriamycin‑induced apoptosis by increasing the generation of reactive oxygen species

Anaplastic thyroid cancer (ATC) is a very aggressive malignancy that is resistant to various types of chemotherapy in humans. Most patients with late-stage ATC cannot undergo surgery and receive chemotherapy drugs. The present study investigated the influence of 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) pretreatment on adriamycin (ADM) chemotherapy efficacy in the 8305c and 8505c ATC cell lines. The apoptotic effects of ADM on ATC cells pretreated with 1,25(OH)₂D₃ were evaluated. Cell viability was identified by using the Cell Counting Kit-8 assay. Apoptosis was assessed by flow cytometry and staining with Hoechst 33342. The expression of the apoptotic protein cleaved caspase-3 was tested with a colorimetric assay kit and by western blotting. Reactive oxygen species (ROS) generation was assessed with the antioxidant N-acetyl-L-cysteine (NAC) and the assay H₂-DCFDA. In addition, ROS production could be reversed by NAC treatment. The present study demonstrated that 1,25(OH)₂D₃ enhanced ADM-induced apoptosis in 8305c and 8505c cell lines. Furthermore, 1,25(OH)₂D₃ improved the ADM-induced ROS production and expression of cleaved caspase-3. NAC treatment inhibited the expression of cleaved caspase-3 in ATC cells, and reduced apoptosis in cells that were pretreated with 1,25(OH)₂D₃ and ADM. These results demonstrated that 1,25(OH)₂D₃ may enhance ADM-induced apoptosis by increasing ROS generation in ATC cells.

Intracellular catalase activity instead of glutathione level dominates the resistance of cells to reactive oxygen species

Artesunate (ARS) induced significant reactive oxygen species (ROS) generation in HepG2, HeLa, and A549 lines. However, ARS induced ROS-dependent apoptosis in HeLa and A549 cell lines but ROS-independent apoptosis in HepG2 cells. A total of 200 μM hydrogen peroxide (H2O2) significantly induced cytotoxicity in HeLa cells, while H2O2 up to 300 μM did not induce cytotoxicity in HepG2 cells, further demonstrating the strong resistance of HepG2 cells to ROS. HeLa cells had much higher basic total glutathione (T-GSH) level than HepG2 cells, while the ratio of basic reduced glutathione (GSH)/oxidized glutathione (GSSG) in HepG2 cells was nearly twice than that in HeLa and A549 cells. Inhibition of glutathione markedly enhanced H2O2- or ARS-induced cytotoxicity in HeLa and A549 cell lines but modestly enhanced the cytotoxicity of H2O2 and even did not affect the cytotoxicity of ARS in HepG2 cells. Moreover, addition of GSH remarkably prevented H2O2- or ARS-induced cytotoxicity in HeLa and A549 cell lines, further indicating the involvement of GSH in scavenging ROS in the two cell lines. HepG2 cells exhibited higher catalase activity than HeLa cells, and inhibiting catalase activity by using 3-aminotriazole (3-AT, a specific inhibition of catalase) or catalase siRNA remarkably reduced the resistance of HepG2 cells to ROS, demonstrating the key roles of catalase for the strong resistance of HepG2 cells to ROS. Collectively, catalase activity instead of glutathione level dominates the resistance of cells to ROS.

Effects of tris(1-chloro-2-propyl)phosphate and tris(2-chloroethyl)phosphate on cell viability and morphological changes in peripheral blood mononuclear cells (in vitro study)

Organophosphorus flame retardants (OPFRs) are a group of chemicals widely used in various everyday use products. Tris(2-chloroethyl)phosphate (TCEP) and tris(1-chloro-2-propyl)phosphate (TCPP) are one of the commonly used chemicals belonging to this group. Due to the need of limitation of the use of polybrominated diphenyl ethers (PBDEs) as retardants, the share of the compounds tested in our experiments in chemicals production systematically increases. There is limited information about the influence of halogenated OPFRs on living cells, especially on the immune system cells. That is why the aim of this study was to assess the impact of TCEP and TCPP on viability and morphological alterations of human peripheral blood mononuclear cells (PBMCs). The cells were incubated with selected flame retardants in the concentrations ranging from 0.001 to 1 mM for 24 h. It was found that TCEP at 1 mM and TCPP at 0.5 mM decreased viability of PBMCs, while only TCPP induced morphological alterations in the incubated cells. The results of our experiments suggest that TCPP is more cytotoxic than TCEP, which can be explained by the presence of methyl groups in the molecule of this compound. Similar to other studies, our data also suggest that OPFRs are suitable replacements for PBDEs.

Metformin and epothilone A treatment up regulate pro-apoptotic PARP-1, Casp-3 and H2AX genes and decrease of AKT kinase level to control cell death of human hepatocellular carcinoma and ovary adenocarcinoma cells

High mortality rates in ovarian and liver cancer are largely a result of resistance to currently used chemotherapy. Here, we investigated genotoxic and pro-oxidant effects of metformin (MET) and epothilone A (A) in combination with respect to apoptosis in HepG2 and SKOV-3 cancer cells. Reactive oxygen species (ROS) was studied using 2',7'-dichlorodihydrofluoresein diacetate, and samples were analyzed for the presence and absence of the N-acetylcysteine (NAC). Expression of genes involved in programmed cell death, oxidative and alkylating DNA damage was measured. Probes were analyzed in the presence of Akt or nuclear factor-κB inhibitor. Compared to either drug alone, combination of epothilone A and metformin was more potent; decreased Akt level; and elevated percentage of apoptotic cells, induced cell cycle arrest at G1 phase and elevated the sub-G1 cell population by increasing the mRNA level of caspase-3, poly (ADP-ribose) polymerase-1 and H2AX. The anticancer effect of the drug combination was partially reversed by NAC supplementation, suggesting that ROS generation is required to induce apoptosis. The present study demonstrates that novel combination such as epothilone A and MET show promise in expanding ovarian and liver cancer therapy.

Differentiating responses of lung cancer cell lines to Doxorubicin exposure: in vitro Raman micro spectroscopy, oxidative stress and bcl-2 protein expression

The potential of Raman micro spectroscopy as an in vitro, non-invasive tool for clinical applications has been demonstrated in recent years, specifically for cancer research. To further illustrate its potential as a high content and label free technique, it is important to show its capability to elucidate drug mechanisms of action and cellular resistances. In this study, cytotoxicity assays were employed to establish the toxicity profiles for 24 hr exposure of lung cancer cell lines, A549 and Calu-1, to the commercially available drug, doxorubicin (DOX). Raman spectroscopy, coupled with Confocal Laser Scanning Microscopy and Flow Cytometry, was used to track the DOX mechanism of action, at a subcellular level, and to study the mechanisms of cellular resistance to DOX. Biomarkers related to the drug mechanism of action and cellular resistance to apoptosis, namely reactive oxygen species (ROS) and bcl-2 protein expression, respectively, were also measured and correlated to Raman spectral profiles. Calu-1 cells are shown to exhibit spectroscopic signatures of both direct DNA damage due to intercalation in the nucleus and indirect damage due to oxidative stress in the cytoplasm, whereas the A549 cell line only exhibits signatures of the former mechanism of action. PCA of nucleolar, nuclear and cytoplasmic regions of A549 and Calu-1 with corresponding loadings of PC1 and PC2.

New potential chemotherapy for ovarian cancer - Combined therapy with WP 631 and epothilone B

Despite more modern therapeutics approaches and the use of new drugs for chemotherapy, patients with ovarian cancer still have poor prognosis and therefore, new strategies for its cure are highly needed. One of the promising ways is combined therapy, which has many advantages as minimizing drug resistance, enhancing efficacy of treatment, and reducing toxicity. Combined therapy has rich and successful history in the field of ovarian cancer treatment. Currently use therapy is usually based on platinum-containing agent (carboplatin or cisplatin) and a member of taxanes (paclitaxel or docetaxel). In the mid-2000s this standard regimen has been expanded with bevacizumab, monoclonal antibody directed to Vascular Endothelial Growth Factor (VEGF). Another drug combination with promising perspectives is WP 631 given together with epothilone B (Epo B). WP 631 is a bisanthracycline composed of two molecules of daunorubicin linked with a p-xylenyl linker. Epo B is a 16-membered macrolide manifesting similar mechanism of action to taxanes. Their effectiveness against ovarian cancer as single agents is well established. However, the combination of WP 631 and Epo B appeared to act synergistically, meaning that it is much more potent than the single drugs. The mechanism lying under its efficacy includes disturbing essential cell cycle-regulating proteins leading to mitotic slippage and following apoptosis, as well as affecting EpCAM and HMGB1 expression. In this article, we summarized the current state of knowledge regarding combined therapy based on WP 631 and Epo B as a potential way of ovarian cancer treatment.

Evaluation of the effect of 2,4-dichlorophenol on oxidative parameters and viability of human blood mononuclear cells (in vitro)

2,4-Dichlorophenol (2,4-DCP) is formed in drinking water as a result of its chlorination, and it is created in the environment during transformation of various xenobiotics such as triclosan or herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). The molecular mechanism depicting the action of phenolic compounds on nucleated blood cells has been insufficiently studied, and therefore, we have assessed the effect of 2,4-DCP on the structure and viability of human peripheral blood mononuclear cells (PBMCs). We have evaluated necrotic, apoptotic, and morphological changes (alterations in the size and granulation) in PBMCs incubated with 2,4-DCP in the concentration ranging from 10 to 500 µg mL−1 for 4 h at 37°C. Moreover, we have estimated changes in reactive oxygen species (ROS) formation, lipid peroxidation, and protein carbonylation in the incubated cells. We have noted that 2,4-DCP increased ROS formation and lipid peroxidation (from 10 µg mL−1) and oxidized proteins (from 50 µg mL−1) in PBMCs. The compound studied also provoked apoptotic (from 50 µg mL−1), necrotic (from 100 µg mL−1) and alterations in the size and granulation (from 50 µg mL−1) in the incubated cells. The analysis of quinolinium 4-[(3-methyl-2(3 H)-benzoxazolylidene)methyl]-1-[3-(trimethyl-ammonio)-propyl]-diiodide/propidium iodide staining revealed that 2,4-DCP (50–250 µg mL−1) more strongly increased the number of apoptotic than necrotic cells, which suggests that this cell death type is mainly provoked by this compound in PBMCs. The observed changes were caused by relatively high concentrations of 2,4-DCP, which cannot influence human organism during environmental exposure and thus may only occur as a result of acute or subacute poisoning with this compound.

Cytotoxicity and induction of apoptosis by formamidinodoxorubicins in comparison to doxorubicin in human ovarian adenocarcinoma cells

BACKGROUND/AIM

In this study we investigated the effect of DOX and five of its derivatives containing a formamidine group (NCHNRR) at the 3' position with pyrrolidine (DOX-F PYR), piperidine (DOX-F PIP), morpholine (DOX-F MOR), N-methylpiperazine (DOX-F PAZ) and hexamethyleneimine (DOX-F HEX) ring on SKOV-3 ovarian cancer cells. We have focused on the anti-proliferative activity and the value of apoptosis induced by tested analogues.

MATERIALS AND METHODS

The following methods were used: spectrophotometric assay with MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide); fluorimetric assays - double staining with Hoechst 33258 and propidium iodide (PI), measurement of caspase-3 activity; flow cytometry methods - phosphatidylserine (PS) externalization using Annexin V-FITC and PI fluorochromes, and TUNEL assay.

RESULTS

All of the investigated derivatives were considerably more cytotoxic to the SKOV-3 cell line than DOX. The predominant type of cell death induced by the anthracycline analogues was apoptosis. Necrotic cells represented only a small percentage (<5%) of all cells. The number of apoptotic cells was dependent on the compound and the incubation time. Moreover, a significant increase in caspase-3 activity, DNA fragmentation, and morphological changes in ovarian cells were observed predominantly in new DOX analogues.

CONCLUSIONS

All new formamidine derivatives of DOX were effective against ovarian cancer cells. They induced mainly the apoptotic pathway of cell death mediated by caspase-3. The most promising results were obtained for DOX-F MOR and DOX-F PAZ. The least potent was DOX-F HEX.

Molecular damage caused by generation of reactive oxygen species in the redox cycle of doxorubicin-transferrin conjugate in human leukemia cell lines

In this study we focused on evaluation of the pro-oxidant properties of doxorubicin-transferrin (DOX-TRF) conjugate and its potency to damage macromolecules which are components of cellular compartments. Our experiments were performed on two human leukemia cell lines: K562 (chronic erythromyeloblastoid leukemia) and CCRF-CEM (acute lymphoblastic leukemia). We determined the reactive oxygen species (ROS) production and programmed cell death (PCD) induction by free DOX and its conjugate. Besides this, the lipid peroxidation and protein damage which can be provoked by DOX alone and DOX-TRF conjugate were assessed. ROS were produced in leukemia cells incubated with free DOX and DOX-TRF conjugate and the extent of apoptosis and necrosis was strongly dependent on the cell line, sensitivity to drug and time of incubation with the investigated compounds. The role of ROS in DOX-TRF conjugate-induced cell death was confirmed by the diminution effects of the antioxidant vitamin C.

Two drugs are better than one. A short history of combined therapy of ovarian cancer

Combined therapy of ovarian cancer has a long history. It has been applied for many years. The first drug which was commonly combined with other chemotherapeutics was cisplatin. It turned out to be effective given together with alkylating agents as well as with taxanes. Another drug which is often the basis of first-line therapy is doxorubicin. The use of traditional chemotherapy is often limited due to side effects. This is why new drugs, targeted specifically at cancer cells (e.g. monoclonal antibodies or epidermal growth factor receptor inhibitors), offer a welcome addition when used in combination with conventional anticancer agents. Drugs applied in combination should be synergistic or at least additive. To evaluate the type of interaction between drugs in a plausible sequence, isobolographic analysis is used. This method allows one to assess whether the two agents could make an efficient combination, which might improve the therapy of ovarian cancer.

Apoptosis Induction by Polygonum minus is related to antioxidant capacity, alterations in expression of apoptotic-related genes, and S-phase cell cycle arrest in HepG2 cell line

Polygonum minus (Polygonaceae) is a medicinal herb distributed throughout eastern Asia. The present study investigated antiproliferative effect of P. minus and its possible mechanisms. Four extracts (petroleum ether, methanol, ethyl acetate, and water) were prepared by cold maceration. Extracts were subjected to phytochemical screening, antioxidant, and antiproliferative assays; the most bioactive was fractionated using vacuum liquid chromatography into seven fractions (F1–F7). Antioxidant activity was measured via total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) assays. Antiproliferative activity was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Most active fraction was tested for apoptosis induction and cell cycle arrest in HepG2 cells using flow cytometry and confocal microscopy. Apoptotic-related gene expression was studied by RT-PCR. Ethyl acetate extract was bioactive in initial assays. Its fraction, F7, exhibited highest antioxidant capacity (TPC; 113.16 ± 6.2 mg GAE/g extract, DPPH; EC₅₀: 30.5 ± 3.2 μg/mL, FRAP; 1169 ± 20.3 μmol Fe (II)/mg extract) and selective antiproliferative effect (IC₅₀: 25.75 ± 1.5 μg/mL). F7 induced apoptosis in concentration- and time-dependent manner and caused cell cycle arrest at S-phase. Upregulation of proapoptotic genes (Bax, p53, and caspase-3) and downregulation of antiapoptotic gene, Bcl-2, were observed. In conclusion, F7 was antiproliferative to HepG2 cells by inducing apoptosis, cell cycle arrest, and via antioxidative effects.

Cellular mechanisms of a new pyrazinone compound that induces apoptosis in SKOV-3 cells

We screened a small molecular library that was designed and independently synthesized in vitro and found a new drug (MY-03-01) that is active against ovarian cancer. We established that MY-03-01 effectively inhibited SKOV-3 cell survival in a dose-dependent manner, based on cell viability rates, and that it not only induced SKOV-3 apoptosis by itself, but also did so synergistically with paclitaxel. Secondly, when MY-03-01 was applied at 40 μM, its hemolytic activity was less than 10%, compared with the control, and there was almost no damage to normal cells at this concentration. In addition, we used DAPI staining and flow cytometry to show that MY- 03-01 could significantly induce apoptosis of SKOV-3 cells. Finally, we found that MY-03-01 likely induced SKOV-3 apoptosis by activating caspase3 and caspase9 through the mitochondrial pathway.

WP 631 and Epo B synergize in SKOV-3 human ovarian cancer cells

Combined therapy is one of the basic methods of treatment different types of cancer. It allows to reduce the side effects of each component while maximizing the therapeutic action. The aim of this study was to evaluate the impact of two new drugs: WP 631 (bisanthracycline) and epothilone B (Epo B), added in combination on the SKOV-3 human ovarian cancer cells. To assess the type of interaction between WP 631 and Epo B isobolografic analysis was applied based on the cytotoxicity of drugs determined by the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolinum bromide) assay. Apoptotic and necrotic cell levels were measured by double staining with Hoechst 33258 and propidium iodide, Annexin V-FITC staining and by using TUNEL assay. The combination of WP 631 and Epo B is more potent than drugs added alone. The quantitative analysis indicated that the major mode of cell death induced by the combination after 72 h treatment was early apoptosis, whereas drugs administered alone generated less intensive apoptosis. The present report demonstrates for the first time that WP 631 and Epo B co-administered synergize in SKOV-3 cell line (Z(ex)/Z(th)<1).

Pro-apoptotic activity of new analog of anthracyclines--WP 631 in advanced ovarian cancer cell line

In this work we investigated the mode of cell death induced by WP 631, a novel anthracycline antibiotic, in the ovarian cancer cell line (OV-90) derived from the malignant ascites of a patient diagnosed with advanced disease. The effects were compared with those of doxorubicin (DOX), a first generation anthracycline. The ability of WP 631 to induce apoptosis and necrosis was examined by double staining with Annexin V and propidium iodide, measurements of the level of intracellular calcium ions and cytochrome c, PARP cleavage. We also investigated the possible involvement of the caspases activation, DNA degradation (comet assay) and intracellular reactive oxygen species (ROS) production in the development of the apoptotic events and their significance for drug efficiency. The results obtained clearly demonstrate that antiproliferative capacity of WP 631 in tested cell line was a few times greater than that of DOX. Furthermore, ovarian cancer cells treated with WP 631 showed a higher mean level of basal DNA damage in comparison to DOX. In conclusion, WP 631 is able to induce caspase - dependent apoptosis in human ovarian cancer cells. Obtained results suggested that WP 631 may be a candidate for further evaluation as chemotherapeutic agents for human cancers.

Dillenia suffruticosa exhibited antioxidant and cytotoxic activity through induction of apoptosis and G2/M cell cycle arrest

ETHNOPHARMACOLOGICAL RELEVANCE

Dillenia suffruticosa (Family: Dilleniaceae) locally known as Simpoh air has been reported to be used traditionally to treat cancerous growth. Therefore, the present study was attempted to investigate the antioxidant and cytotoxic properties of different parts (root, flower, fruit and leaf) of D. suffruticosa extracts.

METHODS AND MATERIALS

In this study, direct solvent extraction (aqueous and methanol) from different parts of D. suffruticosa (root, flower, fruit and leaf) were carried out. Antioxidant activities of D. suffruticosa extract were determined by using DPPH, ABTS FRAP and β-carotene bleaching assays. Cytotoxicity and cell cycle arrest of the active extract were determined using MTT assay and flow cytometer, respectively. Sequential solvent extraction (hexane, DCM, EtOAc, and MeOH) were also carried out in root of D. suffruticosa to further evaluate the antioxidant and cytotoxic activity of the different solvent extracts.

RESULTS

Methanol (MeOH) root extract showed the highest TPC, antioxidant and cytotoxic activities (especially towards HeLa) compared to others (P<0.05). Based on the results, sequential solvent extraction (hexane, DCM, EtOAc and MeOH) was carried out in the roots of D. suffruticosa. MeOH extract exhibited the highest antioxidant activities among others and significantly correlated (P<0.05) with TPC, suggesting the important contribution of phenolic compounds to its antioxidant activity. On the other hand, the DCM and EtOAc exhibited higher cytotoxic activity to selected cancer cells (HeLa, MCF-7, MDA-MB-231, A549 and HT29) compared to others. In short, there is no established correlation between antioxidant and cytotoxic activities of D. suffruticosa extracts indicating that an agent with high antioxidant activities will not necessarily possesses good cytotoxic activities in return. Qualitative phytochemical screening of D. suffruticosa extracts suggested the presence of saponins, triterpenes, sterols, and polyphenolic compounds which are believed to contribute to the cytotoxic activities.

CONCLUSION

It is suggested that the cytotoxicity of the active extracts in HeLa was due to the induction of apoptosis and cell cycle arrest at G2/M.

The roles of beta-adrenergic receptors in tumorigenesis and the possible use of beta-adrenergic blockers for cancer treatment: possible genetic and cell-signaling mechanisms

Cancer is the leading cause of death in the USA, and the incidence of cancer increases dramatically with age. Beta-adrenergic blockers appear to have a beneficial clinical effect in cancer patients. In this paper, we review the evidence of an association between β-adrenergic blockade and cancer. Genetic studies have provided the opportunity to determine which proteins link β-adrenergic blockade to cancer pathology. In particular, this link involves the major histocompatibility complex class II molecules, the renin-angiotensin system, transcription factor nuclear factor-kappa-light-chain-enhancer of activated B cells, poly(ADP-ribose) polymerase-1, vascular endothelial growth factor, and the reduced form of nicotinamide adenine dinucleotide phosphate oxidase. Beta-adrenergic blockers also exert anticancer effects through non-genomic factors, including matrix metalloproteinase, mitogen-activated protein kinase pathways, prostaglandins, cyclooxygenase-2, oxidative stress, and nitric oxide synthase. In conclusion, β-adrenergic blockade may play a beneficial role in cancer treatment. Additional investigations that examine β-adrenergic blockers as cancer therapeutics are required to further elucidate this role.

N-acetylcysteine potentiates doxorubicin-induced ATM and p53 activation in ovarian cancer cells

Doxorubicin has been used clinically to treat various types of cancer, and yet the molecular mode of actions of doxorubicin remains to be fully unraveled. In this study, we investigated the effect of doxorubicin on cultured ovarian cancer cells (CaOV3). MTT assay data showed that doxorubicin inhibits cell proliferation in a time- and dose-dependent manner. Phagokinetic cell motility assay data indicated that doxorubicin inhibits both basal level and EGF-induced cell migration in CaOV3 cells. Confocal microscopic data revealed that doxorubicin induces reorganization of cytoskeletal proteins including actin, tubulin and vimentin. Doxorubicin induces phosphorylation of p53 at Ser15 and 20, acetylation of p53 and ATM activation. Doxorubicin also induces phosphorylation of histone H2AX at Ser139. Interestingly, doxorubicin also inhibits mTOR activity, measured by phosphorylation of S6 ribosomal protein. Pretreatment of CaOV3 cells with antioxidant N-acetylcysteine (NAC), but not pyrrolidine dithiocarbamate (PDTC) potentiates doxorubicin-induced phosphorylation of p53 and ATM. Collectively, we conclude that doxorubicin induces ATM/p53 activation leading to reorganization of cytoskeletal networks, inhibition of mTOR activity, and inhibition of cell proliferation and migration. Our data also suggest that removal of oxidants by antioxidants such as NAC may enhance the efficacy of doxorubicin in vivo.

In vitro acute exposure to DEHP affects oocyte meiotic maturation, energy and oxidative stress parameters in a large animal model

Phthalates are ubiquitous environmental contaminants because of their use in plastics and other common consumer products. Di-(2-ethylhexyl) phthalate (DEHP) is the most abundant phthalate and it impairs fertility by acting as an endocrine disruptor. The aim of the present study was to analyze the effects of in vitro acute exposure to DEHP on oocyte maturation, energy and oxidative status in the horse, a large animal model. Cumulus cell (CC) apoptosis and oxidative status were also investigated. Cumulus-oocyte complexes from the ovaries of slaughtered mares were cultured in vitro in presence of 0.12, 12 and 1200 µM DEHP. After in vitro maturation (IVM), CCs were removed and evaluated for apoptosis (cytological assessment and TUNEL) and intracellular reactive oxygen species (ROS) levels. Oocytes were evaluated for nuclear chromatin configuration. Matured (Metaphase II stage; MII) oocytes were further evaluated for cytoplasmic energy and oxidative parameters. DEHP significantly inhibited oocyte maturation when added at low doses (0.12 µM; P<0.05). This effect was related to increased CC apoptosis (P<0.001) and reduced ROS levels (P<0.0001). At higher doses (12 and 1200 µM), DEHP induced apoptosis (P<0.0001) and ROS increase (P<0.0001) in CCs without affecting oocyte maturation. In DEHP-exposed MII oocytes, mitochondrial distribution patterns, apparent energy status (MitoTracker fluorescence intensity), intracellular ROS localization and levels, mt/ROS colocalization and total SOD activity did not vary, whereas increased ATP content (P<0.05), possibly of glycolytic origin, was found. Co-treatment with N-Acetyl-Cysteine reversed apoptosis and efficiently scavenged excessive ROS in DEHP-treated CCs without enhancing oocyte maturation. In conclusion, acute in vitro exposure to DEHP inhibits equine oocyte maturation without altering ooplasmic energy and oxidative stress parameters in matured oocytes which retain the potential to be fertilized and develop into embryos even though further studies are necessary to confirm this possibility.