Bioremoval and Detoxification of the Anticancer Drug Mitoxantrone Using Immobilized Crude Versatile Peroxidase (icVP/Ba) Bjerkandera adusta CCBAS 930

The aim of this study was to evaluate the biodecolorization and detoxification of the anticancer drug mitoxantron (MTX) by immobilized crude versatile peroxidase of Bjerkandera adusta CCBAS 930 (icVP/Ba). The concentrated crude VP was obtained from B. adusta CCBAS 930 culture on medium with MTX (µg/mL) addition, immobilized with 4% sodium alginate. MTX removal degree (decolorization), levels of phenolic compounds and free radicals were determined during MTX biotransformation. Moreover, the phytotoxicity (Lepidium sativum L.), biotoxicity (multi-species microbial assay, MARA), and genotoxicity (SOS Chromotest) of MTX were evaluated before and after the biological treatment. The use of icVP/Ba (95 U/mL) significantly shortened the bioremoval of 10 µg/mL MTX (95.57% after 72 h). MTX removal by icVP/Ba was correlated with an 85% and 90% decrease in the levels of phenolic compounds and free radicals, respectively. In addition, the use of icVP/Ba contributed to a decrease in the phyto-, bio-, and genotoxicity of MTX. This is the first study to describe the possibility of removing MTX using immobilized crude fungal peroxidase.

Enhanced Efficiency of the Removal of Cytostatic Anthracycline Drugs Using Immobilized Mycelium of Bjerkandera adusta CCBAS 930

The aim of this study was to evaluate the bioremoval of anthracycline antibiotics (daunomycin-DNR, doxorubicin-DOX, and mitoxantrone-MTX) by immobilized mycelium of B. adusta CCBAS 930. The activity of oxidoreductases: versatile peroxidases (VP), superoxide dismutase (SOD), catalase (CAT), and glucose oxidase (GOX), and the levels of phenolic compounds (PhC) and free radicals (SOR) were determined during the biotransformation of anthracyclines by B. adusta strain CCBAS 930. Moreover, the phytotoxicity (Lepidium sativum L.), biotoxicity (MARA assay), and genotoxicity of anthracyclines were evaluated after biological treatment. After 120 h, more than 90% of anthracyclines were removed by the immobilized mycelium of B. adusta CCBAS 930. The effective biotransformation of anthracyclines was correlated with detoxification and reduced genotoxicity.

Is it possible to cure childhood acute myeloid leukaemia without significant cardiotoxicity?

Since cardiotoxicity is a life threatening late effect, a reduction of cardiotoxicity in the treatment of acute myeloid leukaemia (AML) is essential. This review is a compilation of the current knowledge about cardiotoxicity after AML treatment and of how future directions in treatment may affect its incidence. A total of six studies concerning AML and cardiotoxicity were identified. The incidence of late subclinical cardiotoxicity varied between 1·3 and 15·3%, and late clinical cardiotoxicity varied between 1·3 and 9·3%. Cumulative dose of anthracyclines (ACs) and history of relapse were the most common risk factors identified. No conclusions could be drawn about new, potentially less toxic ACs. Differences in treatment data and variations in study populations made comparisons uncertain. The echocardiographic techniques used in the majority of the studies are inferior to more modern echocardiographic methods. This decreases reproducibility and may increase the risk of overestimation of cardiotoxicity. In summary, AML cannot be cured today without ACs. However, some ACs may cause less cardiotoxicity than others. Furthermore there is currently no consensus on equipotent doses of ACs and risk factors for cardiotoxicity. Further research including randomized trials is needed to evaluate whether or not the potentially less cardiotoxic agents fulfil their promise.

Role of nucleotide excision repair proteins in response to DNA damage induced by topoisomerase II inhibitors

In cancer treatment, chemotherapy is one of the main strategies used. The knowledge of the cellular and molecular characteristics of tumors allows the use of more specific drugs, making the removal of tumors more efficient. Among the drugs of choice in these treatments, topoisomerase inhibitors are widely used against different types of tumors. Topoisomerases are enzymes responsible for maintaining the structure of DNA, altering its topological state temporarily during the processes of replication and transcription, in order to avoid supercoiling and entanglements at the double helix. The DNA damage formed as a result of topoisomerase inhibition can be repaired by DNA repair mechanisms. Thus, DNA repair pathways can modulate the effectiveness of chemotherapy. Homologous recombination (HR) and non-homologous end joining (NHEJ) are the main pathways involved in the removal of double strand breaks (DSBs); while nucleotide excision repair (NER) is mainly characterized by the removal of lesions that lead to significant structural distortions in the DNA double helix. Evidence has shown that DSBs are the main type of damage resulting from the inhibition of the DNA topoisomerase II enzyme, and therefore the involvement of HR and NHEJ pathways in the repair process is well established. However, some topoisomerase II inhibitors induce other types of lesions, like DNA adducts, interstrand crosslinks and reactive oxygen species, and studies have shown that other DNA repair pathways might be participating in removing injury induced by these drugs. This review aims to correlate the involvement of proteins from different DNA repair pathways in response to these drugs, with an emphasis on NER.

Cardiac function in survivors of childhood acute myeloid leukemia treated with chemotherapy only: a NOPHO-AML study

OBJECTIVES

We report cardiac function of patients treated for Childhood acute myeloid leukemia with chemotherapy only according to three consecutive Nordic protocols.

METHODS

Ninety-eight of 138 eligible patients accepted examination with standardized echocardiography. Results were compared with age- and sex-matched controls.

RESULTS

The median age was 3 yr at diagnosis (range 0-15), and the median time from diagnosis to study was 11 yr (4-25). All but one patient had received doxorubicin and 90% had received mitoxantrone. The median cumulative dose of daunorubicin equivalents was 300 mg/m(2) (210-525). Left ventricular fractional shortening (LVFS) and ejection fraction (LVEF) were lower in patients than in controls (32.6% (SD 4.0) vs. 35.2% (SD 3.4), P = 0.002 and 59.9% (SD 5.5) vs. 64.2% (SD 4.4), P = 0.001). The myocardial performance index (MPI) was higher in patients than in controls (0.32 (SD 0.081) vs. 0.26 (SD 0.074), P < 0.0001). Cumulative dose of doxorubicin but not mitoxantrone was related to lower LVFS (P = 0.037) and LVEF (P = 0.016). Longer follow-up was associated with lower LVFS (P = 0.034). Higher MPI was associated with young age at diagnosis (P = 0.04) and longer follow-up (P = 0.031).

CONCLUSIONS

In this study, most patients had cardiac function within normal limits and reported very few cardiac symptoms. However, compared with healthy controls, they had significantly reduced left ventricular function.

Short-chain glycoceramides promote intracellular mitoxantrone delivery from novel nanoliposomes into breast cancer cells

PURPOSE

To improve therapeutic activity of mitoxantrone (MTO)-based chemotherapy by reducing toxicity through encapsulation in nanoliposomes and enhancing intracellular drug delivery using short-chain sphingolipid (SCS) mediated tumor cell membrane permeabilization.

METHODS

Standard (MTOL) and nanoliposomes enriched with the SCS, C8-Glucosylceramide or C8-Galactosylceramide (SCS-MTOL) were loaded by a transmembrane ammonium sulphate gradient and characterized by DLS and cryo-TEM. Intracellular MTO delivery was measured by flow cytometry and imaged by fluorescence microscopy. In vitro cytotoxicity was studied in breast carcinoma cell lines. Additionally, live cell confocal microscopy addressed the drug delivery mechanism by following the intracellular fate of the nanoliposomes, the SCS and MTO. Intratumoral MTO localization in relation to CD31-positive tumor vessels and CD11b positive cells was studied in an orthotopic MCF-7 breast cancer xenograft.

RESULTS

Stable SCS-MTOL were developed increasing MTO delivery and cytotoxicity to tumor cells compared to standard MTOL. This effect was much less pronounced in normal cells. The drug delivery mechanism involved a transfer of SCS to the cell membrane, independently of drug transfer and not involving nanoliposome internalization. MTO was detected intratumorally upon MTOL and SCS-MTOL treatment, but not after free MTO, suggesting an important improvement in tumor drug delivery by nanoliposomal formulation. Nanoliposomal MTO delivery and cellular uptake was heterogeneous throughout the tumor and clearly correlated with CD31-positive tumor vessels. Yet, MTO uptake by CD11b positive cells in tumor stroma was minor.

CONCLUSIONS

Nanoliposomal encapsulation improves intratumoral MTO delivery over free drug. Liposome bilayer-incorporated SCS preferentially permeabilize tumor cell membranes enhancing intracellular MTO delivery.

Green tea catechins increase the force of contraction in isolated guinea pig atrial muscle preparations by increasing the amplitude of intracellular Ca2+ concentration

It has been reported that green tea catechins enhance the force of contraction of isolated heart muscle preparations. However, it remains controversial whether or not the increase in force of contraction is related to an increase in the intracellular Ca(2+) concentration ([Ca(2+)]i). In this study, the relationship was investigated using a left atrial muscle preparation isolated from guinea pig heart. In the left atrial muscle preparations without fura-2/AM loading, neither EGC (epigallocatechin) nor EC (epicatechin) influenced the force of contraction, but EGCG (epigallocatechin gallate) and ECG (epicatechin gallate) increased the force of contraction in a dose-dependent manner. The ED(50) value of EGCG was significantly higher than that of ECG. In the atrial muscle preparations loaded with fura-2/AM, EGCG and ECG increased the amplitude of [Ca(2+)]i(peak [Ca(2+)]i minus diastolic [Ca(2+)]i) which is associated with the increase in force of contraction. Simple regression analysis between the degree of increase in the force of contraction and the increase in the amplitude of [Ca(2+)]i revealed a positive correlation in EGCG, ECG and CaCl(2). In addition, the slopes of the regression lines of EGCG and ECG were comparable with those of CaCl(2). It was suggested that atrial muscle preparations had a higher affinity for ECG than EGCG, and that the increase in the force of contraction by EGCG and ECG was closely related to the increase in the amplitude of [Ca(2+)]i.

Treatment of acute promyelocytic leukemia during pregnancy

Management of the pregnant patient with acute promyelocytic leukemia (APL) is a challenge. Immediate treatment of APL is critical, as it is an oncologic emergency, with a high risk of morbidity and mortality associated with disseminated intravascular coagulation. However, administration of chemotherapy and differentiating agents in pregnancy is controversial because of potential teratogenic effects. In addition, complications associated with APL, including retinoic acid syndrome, add to the complexity of management. To better understand how to manage this complex patient care situation, we searched the PubMed database (January 1972-May 2008) for English-language articles about maternal and fetal outcomes resulting from APL treatment during pregnancy. A total of 42 cases from 35 articles were identified: 12 first-trimester, 21 second-trimester, and 9 third-trimester cases. The most commonly administered agents were all-trans-retinoic acid (ATRA), anthracyclines, and antimetabolites. Complete remission was reported in 35 (83%) of 42 patients. Administration of ATRA or chemotherapy in the first trimester was associated with an increased risk of fetal malformations and spontaneous abortion, whereas administration in the second and third trimesters was associated with relatively favorable fetal outcomes. The overall treatment of the pregnant patient with APL should include a discussion about pregnancy termination, especially if APL is diagnosed in the first trimester. If the pregnancy is to continue, then the appropriate chemotherapy regimen needs to be determined. Frequent fetal monitoring, along with aggressive management of potential APL-related complications, is necessary to allow for optimal maternal and fetal outcomes.