scholarly journals The Cytotoxicity of Benzaldehyde Nitrogen Mustard-2-Pyridine Carboxylic Acid Hydrazone Being Involved in Topoisomerase IIαInhibition

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Yun Fu ◽  
Sufeng Zhou ◽  
Youxun Liu ◽  
Yingli Yang ◽  
Xingzhi Sun ◽  
...  
Keyword(s):  
Dna Cleavage ◽  
Topoisomerase Ii ◽  
Nitrogen Mustard ◽  
Alkylating Agents ◽  
Iron Chelators ◽  
Ros Generation ◽  
Antitumor Property ◽  
Pyridine Carboxylic Acid ◽  
Pyridine Carboxylic

The antitumor property of iron chelators and aromatic nitrogen mustard derivatives has been well documented. Combination of the two pharmacophores in one molecule in drug designation is worth to be explored. We reported previously the syntheses and preliminary cytotoxicity evaluation of benzaldehyde nitrogen mustard pyridine carboxyl acid hydrazones (BNMPH) as extended study, more tumor cell lines (IC50for HepG2: 26.1 ± 3.5 μM , HCT-116: 57.5 ± 5.3 μM, K562: 48.2 ± 4.0 μM, and PC-12: 19.4 ± 2.2 μM) were used to investigate its cytotoxicity and potential mechanism.In vitroexperimental data showed that the BNMPH chelating Fe2+caused a large number of ROS formations which led to DNA cleavage, and this was further supported by comet assay, implying that ROS might be involved in the cytotoxicity of BNMPH. The ROS induced changes of apoptosis related genes, but the TFR1 and NDRG1 metastatic genes were not obviously regulated, prompting that BNMPH might not be able to deprive Fe2+of ribonucleotide reductase. The BNMPH induced S phase arrest was different from that of iron chelators (G1) and alkylating agents (G2). BNMPH also exhibited its inhibition of human topoisomerase IIα. Those revealed that the cytotoxic mechanism of the BNMPH could stem from both the topoisomerase II inhibition, ROS generation and DNA alkylation.

scholarly journals Site-specific DNA cleavage by mammalian DNA topoisomerase II induced by novel flavone and catechin derivatives

1992 ◽  
Vol 282 (3) ◽  
pp. 883-889 ◽  
Author(s):  
C A Austin ◽  
S Patel ◽  
K Ono ◽  
H Nakane ◽  
L M Fisher
Keyword(s):  
Dna Cleavage ◽  
Topoisomerase Ii ◽  
Complex Analysis ◽  
Antiviral Agents ◽  
Epigallocatechin Gallate ◽  
Tea Plant ◽  
Epicatechin Gallate ◽  
Pyrone Ring ◽  
Cleavable Complex

Four naturally occurring flavones (baicalein, quercetin, quercetagetin and myricetin) and two novel catechins [(-)-epicatechin gallate and (-)-epigallocatechin gallate, from the tea plant Camellia sinensis], which are known inhibitors of reverse transcriptase, were shown to induce mammalian topoisomerase II-dependent DNA-cleavage in vitro. The flavones differed from the catechins in causing unwinding of duplex DNA, but both classes of compound induced enzymic DNA breakage at the same sites on DNA. Moreover, the cleavage specificity was the same as that for the known intercalator 4′-(acridin-9-ylamino)methanesulphon-m-anisidide, suggesting that these agents trap the same cleavable complex. Analysis of some 30 flavonoid compounds allowed elucidation of the structure-function relationships for topoisomerase II-mediated DNA cleavage. For flavonoid inhibitors an unsaturated double bond between positions 2 and 3 of the pyrone ring and hydroxy groups at the 5, 7, 3′ and 4′ positions favoured efficient cleavage. Hydroxy substitutions could be tolerated at the 3, 6 and 5′ positions. Indeed, the absence of substituents at the 3′, 4′ and 5′ positions could be compensated by a hydroxy group at position 6 (baicalein). Similar requirements have been reported for flavonoid inhibitors of protein kinase C that act competitively with ATP, suggesting interaction with a conserved protein feature. Formation of the cleavable complex is a cytotoxic lesion that may contribute to the growth-inhibitory properties of flavones observed for three human tumour cell lines. These results are discussed in regard to the selectivity of antiviral agents.

Oxidative Stress in Red Blood Cells, Platelets and Polymorphonuclear Leukocytes from Patients with Myelodysplastic Syndrome.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2632-2632
Author(s):  
Eitan Fibach ◽  
Hussam Ghoti ◽  
Johnny Amer ◽  
Asher Winder ◽  
Eliezer Rachmilewitz
Keyword(s):  
Oxidative Stress ◽  
Myelodysplastic Syndrome ◽  
Blood Cells ◽  
Cell Damage ◽  
Iron Chelator ◽  
Oxidative Status ◽  
Iron Chelators ◽  
Ros Generation ◽  
Transfusion Requirements

Abstract Myelodysplastic syndrome (MDS) is characterized by refractory cytopenias due to ineffective hematopoiesis. Some patients with severe anemia require multiple blood transfusions and develop iron overload. Consequently, reactive oxygen species (ROS) are generated concomitant with a decrease in cellular antioxidants such as reduced gluthatione (GSH). The generated oxidative stress contributes to cell damage, apoptosis and ineffective hematopoiesis. Using flow cytometry, we measured the oxidative state of RBC, platelets and PMN in 14 low-risk MDS patients and 25 normal donors. The results indicate that the majority of the patients had higher ROS in RBC (2.79-fold) and platelets (2.91-fold) and lower GSH in their RBC (3.4-fold) and platelets (2.1-fold) than normal (p<0.005). As for PMN, there were no significant differences in ROS, although GSH was significantly (p<0.1) lower in MDS compared with normal donors. The oxidative stress in MDS cells could be ameliorated by a short in vitro treatment with the iron-chelators deferrioxamine and deferiprone, or with the anti-oxidant N-acetylcysteine. These results suggest that the decrease in transfusion requirements with increase in platelet and PMN counts in MDS patients treated with deferrioxamine may be due to indirect antioxidant effect of the iron chelator and suggest that treatment with a combination of iron-chelators and anti-oxidants might be more effective. ROS generation and GSH content in MDS blood cells ROS generation and GSH content in MDS blood cells Effect of iron chelations and an antioxidant on the oxidative status of MDS cells Effect of iron chelations and an antioxidant on the oxidative status of MDS cells

Adaphostin-Induced Apoptosis in CLL B-Cells Is Associated with Induction of Oxidative Stress and Exhibits Synergy with Fludarabine.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3482-3482 ◽  
Author(s):  
Tait D. Shanafelt ◽  
Y. Kit Lee ◽  
Nancy D. Bone ◽  
Ann K. Strege ◽  
Scott H. Kaufmann ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Cell Death ◽  
B Cells ◽  
Alkylating Agents ◽  
Single Agent ◽  
Lymphocytic Leukemia ◽  
Parp Cleavage ◽  
Ros Generation ◽  
Mutation Status

Abstract Background : B-Chronic Lymphocytic leukemia (CLL) is the most common leukemia in North America. The standard current treatments use purine nucleoside analogues as single agent therapy or in combination with rituximab, steroids, and alkylating agents. Overall response rates with these treatments in previously untreated patients may reach 90 % with CR rates of 50–60%, however, most patients will relapse. Thus, despite refinements in therapy, CLL remains an incurable malignancy and there remains significant and urgent need to identify and develop new agents with novel mechanisms of action for the treatment of CLL. In line with this we have explored the mechanism and in vitro activity for a tyrphostin, adaphostin. Methods: We evaluated the in vitro efficacy of adaphostin to induce apoptosis in CLL B-cells. Peripheral blood was collected from patients with CLL (n=57). Highly purified CLL B-cells ((minimum 80% CD19+, mean 92.2% CD19+ and 94.4% CD19+/CD5+ positive)) were cultured with freshly prepared adaphostin for 24 – 120 hours. Cell death was analyzed by flow cytometry using Anexin V/Propidium iodide (PI). PARP cleavage and anti-apoptotic protein levels were measured by immunoblot techniques. The effect of combination treatment on CLL B cells with adaphostin and fludarabine on CLL B-cells was also assessed. Results: Analysis by Annexin V/PI staining revealed that the mean IC50 for adaphostin at 24 h was 4.2 uM (range 1.10 uM-11.25 uM; median = 4.25; n = 29) for CLL isolates and >10 uM for B and T-cells isolated from normal donors. Median IC50 levels for Adaphostin were not significantly different based on IgVH mutation status, level of CD38 expression, or cytogenetic abnormalities by FISH testing (Table 1). Immunoblots demonstrated adaphostin-induced PARP cleavage and cleavage of caspase 3 substrates, suggesting that adaphostin induces cell death through apoptosis. Adaphostin increased the intra-cellular level of reactive oxygen species (ROS) in CLL B-cells; and the antioxidant N-acetylcysteine blocked both adaphostin-induced ROS generation and apoptosis (mean reduction cell death=60%; range 23–99% reduction) suggesting generation of ROS is critical to adaphostin’s induction of apoptosis. Adaphostin also caused a decrease in the level of the anti-apoptotic proteins Bcl-2 in a majority of patients on both flow cytometry and immunoblots. When adaphostin was combined with fludarabine (F-ARA-ATP), a synergistic effect on cell death was observed in all 10 CLL samples when analyzed by mathematical modeling software. Summary: These findings indicate that adaphostin induces selective apoptosis in CLL B-cells from all risk categories through a mechanism that involves ROS generation. Importantly, we also demonstrate its ability to augment the effects of fludarabine. We continue to explore the preclinical development of adaphostin as a novel agent for the treatment of CLL. IC50 Adaphostin Dose Levels by Prognostic Groups FACTOR N Median IC 50 Adaphostin Range p-Value     Rai Stage Group Low/Int (0–II) 19 4.7 1.8 – 11.25 0.018 High (III – IV) 10 3.05 1.1 – 5.4 - IgVH Mutation Status Mutated 11 4.45 1.1 – 11.25 0.72 Nonmutated 10 3.93 1.8 – 5.8 - CD38 Status Negative 20 4.55 1.1 – 11.25 0.74 Positive 9 4.25 1.8 – 6.6 -     FISH defects 13q- 8 4.70 1.75 – 11.25 Normal 6 3.53 1.1 – 5.8 0.83 12+ 4 3.93 2.25 – 6.6 17p/11q 5 4.20 2.0 – 5.4

Similar sequence specificity of mitoxantrone and VM-26 stimulation of in vitro DNA cleavage by mammalian DNA topoisomerase II

Biochemistry ◽  
1993 ◽  
Vol 32 (12) ◽  
pp. 3038-3046 ◽  
Author(s):  
Giovanni Capranico ◽  
Paola De Isabella ◽  
Stella Tinelli ◽  
Mario Bigioni ◽  
Franco Zunino
Keyword(s):  
Dna Cleavage ◽  
Topoisomerase Ii ◽  
Sequence Specificity ◽  
Dna Topoisomerase Ii ◽  
Similar Sequence ◽  
Dna Topoisomerase ◽  
Stimulation Of

The in vivo distribution and dynamics of DNA topoisomerase II in Drosophila embryonic nuclei and chromosomes

1993 ◽  
Vol 51 ◽  
pp. 74-75
Author(s):  
Jason R. Swedlow ◽  
Neil Osheroff ◽  
Tim Karr ◽  
John W. Sedat ◽  
David A. Agard
Keyword(s):  
Topoisomerase Ii ◽  
Biochemical Characterization ◽  
Developmental Cycle ◽  
Dna Topoisomerase Ii ◽  
Chromosomal Distribution ◽  
Dna Topoisomerase ◽  
Ideal System ◽  
Dnase Treatment

DNA topoisomerase II is an ATP-dependent double-stranded DNA strand-passing enzyme that is necessary for full condensation of chromosomes and for complete segregation of sister chromatids at mitosis in vivo and in vitro. Biochemical characterization of chromosomes or nuclei after extraction with high-salt or detergents and DNAse treatment showed that topoisomerase II was a major component of this remnant, termed the chromosome scaffold. The scaffold has been hypothesized to be the structural backbone of the chromosome, so the localization of topoisomerase II to die scaffold suggested that the enzyme might play a structural role in the chromosome. However, topoisomerase II has not been studied in nuclei or chromosomes in vivo. We have monitored the chromosomal distribution of topoisomerase II in vivo during mitosis in the Drosophila embryo. This embryo forms a multi-nucleated syncytial blastoderm early in its developmental cycle. During this time, the embryonic nuclei synchronously progress through 13 mitotic cycles, so this is an ideal system to follow nuclear and chromosomal dynamics.

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