Anthracyclines in the treatment of cancer. An overview

Doxorubicin Changes Bax /Bcl-xL Ratio, Caspase-8 and 9 in Breast Cancer Cells

PURPOSE

Doxorubicin is administrated as a single agent in first-line therapy of breast cancer to induce apoptosis in tumor cells. Bax, Bcl-xL, Caspase-8 and 9 proteins are involved in induction of apoptosis. The present study describes Bax, Bcl-xL gene expression and Caspase-8 and 9 protein levels in MCF-7 cells incubated with doxorubicin at different doses an incubation times.

METHODS

The cytotoxic effects of doxorubicin were studied using MTT assay. MCF-7 cells were treated with three concentrations of doxorubicin (0.1, 0.5, 1 μM) and incubated for 24, 48 and 72 hours then expression levels of Bax and Bcl-xL genes were elucidated by Real-time RT-PCR technique and protein levels of caspase-8 and caspase-9 proteins were measured using ELISA method. Morphological modifications of the cells were also monitored via light microscopic images.

RESULTS

Doxorubicin decreased the anti-apoptotic Bcl-xL and increased pro-apoptotic Bax mRNA levels. Doxorubicin induced a significant increase in Bax /Bcl-xL ratio in all doses and incubation times (p<0.05). Highest (more than 10 fold) increase in Bax /Bcl-xL ratio was revealed after 48 h incubation of the cells with in all doses of doxorubicin. Doxorubicin also increased caspase-9 level in a time and dose-dependent manner, while caspase-8 level didn't follow time and dose dependency pattern.

CONCLUSION

Our results confirm that doxorubicin induces mitochondrial-dependent apoptosis by down-regulation of Bcl-xL and up- regulation of Bax and caspase-9 expressions.

Sensitization of breast cancer cells to doxorubicin via stable cell line generation and overexpression of DFF40

There are a number of reports demonstrating a relationship between the alterations in DFF40 expression and development of some cancers. Here, increased DFF40 expression in T-47D cells in the presence of doxorubicin was envisaged for therapeutic usage. The T-47D cells were transfected with an eukaryotic expression vector encoding the DFF40 cDNA. Following incubation with doxorubicin, propidium iodide (PI) staining was used for cell cycle distribution analysis. The rates of apoptosis were determined by annexin V/PI staining. Apoptosis was also evaluated using the DNA laddering analysis. The viability of DFF40-transfected cells incubated with doxorubicin was significantly decreased compared with control cells. However, there were no substantial changes in the cell cycle distribution of pIRES2-DFF40 cells incubated with doxorubicin compared to control cells. The expression of DFF40, without doxorubicin incubation, had also no significant effect on the cell cycle distribution. There was no DNA laddering in cells transfected with the empty pIRES2 vector when incubated with doxorubicin. In contrast, DNA laddering was observed in DFF40 transfected cells in the presence of doxorubicin after 48 h. Also, the expression of DFF40 and DFF45 was increased in DFF40 transfected cells in the presence of doxorubicin enhancing cell death. Collectively our results indicated that co-treatment of DFF40-transfected cells with doxorubicin can enhance the killing of these tumor cells via apoptosis. Thus, modulation of DFF40 level may be a beneficial strategy for treatment of chemo-resistant cancers.

G2/M Cell Cycle Arrest and Tumor Selective Apoptosis of Acute Leukemia Cells by a Promising Benzophenone Thiosemicarbazone Compound

Anti-mitotic therapies have been considered a hallmark in strategies against abnormally proliferating cells. Focusing on the extensively studied family of thiosemicarbazone (TSC) compounds, we have previously identified 4,4'-dimethoxybenzophenone thiosemicarbazone (T44Bf) as a promising pharmacological compound in a panel of human leukemia cell lines (HL60, U937, KG1a and Jurkat). Present findings indicate that T44Bf-mediated antiproliferative effects are associated with a reversible chronic mitotic arrest caused by defects in chromosome alignment, followed by induced programmed cell death. Furthermore, T44Bf selectively induces apoptosis in leukemia cell lines when compared to normal peripheral blood mononuclear cells. The underlying mechanism of action involves the activation of the mitochondria signaling pathway, with loss of mitochondrial membrane potential and sustained phosphorylation of anti-apoptotic protein Bcl-xL as well as increased Bcl-2 (enhanced phosphorylated fraction) and pro-apoptotic protein Bad levels. In addition, ERK signaling pathway activation was found to be a requisite for T44Bf apoptotic activity. Our findings further describe a novel activity for a benzophenone thiosemicarbazone and propose T44Bf as a promising anti-mitotic prototype to develop chemotherapeutic agents to treat acute leukemia malignancies.

Progress in adjuvant chemotherapy for breast cancer: an overview

Breast cancer is the most common cause of cancer and cancer death worldwide. Although most patients present with localized breast cancer and may be rendered disease-free with local therapy, distant recurrence is common and is the primary cause of death from the disease. Adjuvant systemic therapies are effective in reducing the risk of distant and local recurrence, including endocrine therapy, anti-HER2 therapy, and chemotherapy, even in patients at low risk of recurrence. The widespread use of adjuvant systemic therapy has contributed to reduced breast cancer mortality rates. Adjuvant cytotoxic chemotherapy regimens have evolved from single alkylating agents to polychemotherapy regimens incorporating anthracyclines and/or taxanes. This review summarizes key milestones in the evolution of adjuvant systemic therapy in general, and adjuvant chemotherapy in particular. Although adjuvant treatments are routinely guided by predictive factors for endocrine therapy (hormone receptor expression) and anti-HER2 therapy (HER2 overexpression), predicting benefit from chemotherapy has been more challenging. Randomized studies are now in progress utilizing multiparameter gene expression assays that may more accurately select patients most likely to benefit from adjuvant chemotherapy.

Potent Paracrine Effects of human induced Pluripotent Stem Cell-derived Mesenchymal Stem Cells Attenuate Doxorubicin-induced Cardiomyopathy

Transplantation of bone marrow mesenchymal stem cells (BM-MSCs) can protect cardiomyocytes against anthracycline-induced cardiomyopathy (AIC) through paracrine effects. Nonetheless the paracrine effects of human induced pluripotent stem cell-derived MSCs (iPSC-MSCs) on AIC are poorly understood. In vitro studies reveal that doxorubicin (Dox)-induced reactive oxidative stress (ROS) generation and cell apoptosis in neonatal rat cardiomyocytes (NRCMs) are significantly reduced when treated with conditioned medium harvested from BM-MSCs (BM-MSCs-CdM) or iPSC-MSCs (iPSC-MSCs-CdM). Compared with BM-MSCs-CdM, NRCMs treated with iPSC-MSCs-CdM exhibit significantly less ROS and cell apoptosis in a dose-dependent manner. Transplantation of BM-MSCs-CdM or iPSC-MSCs-CdM into mice with AIC remarkably attenuated left ventricular (LV) dysfunction and dilatation. Compared with BM-MSCs-CdM, iPSC-MSCs-CdM treatment showed better alleviation of heart failure, less cardiomyocyte apoptosis and fibrosis. Analysis of common and distinct cytokines revealed that macrophage migration inhibitory factor (MIF) and growth differentiation factor-15 (GDF-15) were uniquely overpresented in iPSC-MSC-CdM. Immunodepletion of MIF and GDF-15 in iPSC-MSCs-CdM dramatically decreased cardioprotection. Injection of GDF-15/MIF cytokines could partially reverse Dox-induced heart dysfunction. We suggest that the potent paracrine effects of iPSC-MSCs provide novel “cell-free” therapeutic cardioprotection against AIC, and that MIF and GDF-15 in iPSC-MSCs-CdM are critical for these enhanced cardioprotective effects.

Room-temperature phosphorescence logic gates developed from nucleic acid functionalized carbon dots and graphene oxide

Room-temperature phosphorescence (RTP) logic gates were developed using capture ssDNA (cDNA) modified carbon dots and graphene oxide (GO). The experimental results suggested the feasibility of these developed RTP-based "OR", "INHIBIT" and "OR-INHIBIT" logic gate operations, using Hg(2+), target ssDNA (tDNA) and doxorubicin (DOX) as inputs.

Sulforaphane prevents doxorubicin-induced oxidative stress and cell death in rat H9c2 cells

Sulforaphane, a natural isothiocyanate compound found in cruciferous vegetables, has been shown to exert cardioprotective effects during ischemic heart injury. However, the effects of sulforaphane on cardiotoxicity induced by doxorubicin are unknown. Thus, in the present study, H9c2 rat myoblasts were pre-treated with sulforaphane and its effects on cardiotoxicity were then examined. The results revealed that the pre-treatment of H9c2 rat myoblasts with sulforaphane decreased the apoptotic cell number (as shown by trypan blue exclusion assay) and the expression of pro-apoptotic proteins (Bax, caspase-3 and cytochrome c; as shown by western blot analysis and immunostaining), as well as the doxorubicin-induced increase in mitochondrial membrane potential (measured by JC-1 assay). Furthermore, sulforaphane increased the mRNA and protein expression of heme oxygenase-1 (HO-1, measured by RT-qPCR), which consequently reduced the levels of reactive oxygen species (ROS, measured using MitoSOX Red reagent) in the mitochondria which were induced by doxorubicin. The cardioprotective effects of sulforaphane were found to be mediated by the activation of the Kelch-like ECH-associated protein 1 (Keap1)/NF-E2-related factor-2 (Nrf2)/antioxidant-responsive element (ARE) pathway, which in turn mediates the induction of HO-1. Taken together, the findings of this study demonstrate that sulforaphane prevents doxorubicin-induced oxidative stress and cell death in H9c2 cells through the induction of HO-1 expression.

Nutrition Modulation of Cardiotoxicity and Anticancer Efficacy Related to Doxorubicin Chemotherapy by Glutamine and ω-3 Polyunsaturated Fatty Acids

BACKGROUND

Doxorubicin (DOX) has been one of the most effective antitumor agents against a broad spectrum of malignancies. However, DOX-induced cardiotoxicity forms the major cumulative dose-limiting factor. Glutamine and ω-3 polyunsaturated fatty acids (PUFAs) are putatively cardioprotective during various stresses and/or have potential chemosensitizing effects during cancer chemotherapy.

METHODS

Antitumor activity and cardiotoxicity of DOX treatment were evaluated simultaneously in a MatBIII mammary adenocarcinoma tumor-bearing rat model treated with DOX (cumulative dose 12 mg/kg). Single or combined treatment of parenteral glutamine (0.35 g/kg) and ω-3 PUFAs (0.19 g/kg eicosapentaenoic acid and 0.18 g/kg docosahexaenoic acid) was administered every other day, starting 6 days before chemotherapy initiation until the end of study (day 50).

RESULTS

Glutamine alone significantly prevented DOX-related deterioration of cardiac function, reduced serum cardiac troponin I levels, and diminished cardiac lipid peroxidation while not affecting tumor inhibition kinetics. Single ω-3 PUFA treatment significantly enhanced antitumor activity of DOX associated with intensified tumoral oxidative stress and enhanced tumoral DOX concentration while not potentiating cardiac dysfunction or increasing cardiac oxidative stress. Intriguingly, providing glutamine and ω-3 PUFAs together did not consistently confer a greater benefit; conversely, individual benefits on cardiotoxicity and chemosensitization were mostly attenuated or completely lost when combined.

CONCLUSIONS

Our data demonstrate an interesting differentiality or even dichotomy in the response of tumor and host to single parenteral glutamine and ω-3 PUFA treatments. The intriguing glutamine × ω-3 PUFA interaction observed draws into question the common assumption that there are additive benefits of combinations of nutrients that are beneficial on an individual basis.

Intensified home haemodialysis for managing severe cardiac failure

BACKGROUND

Conventional thrice weekly haemodialysis (HD) provides adequate dialysis to prevent mortality, but morbidity is prevalent in both the paediatric and adult population. There has been growing interest in the potential of intensive dialysis regimes entering the realm of optimal dialysis, with superior health and quality of life outcomes.

CASE DIAGNOSIS/TREATMENT

We present the case of a 13-year-old girl who had bilateral nephrectomies as a result of bilateral Wilms tumors. In the third year of treatment with conventional HD, she presented with symptomatic progressive cardiac failure, presumably secondary to anthracycline-induced cardiomyopathy. Consequently, she was taken off the renal transplant list and became increasingly dependent on frequent in-centre dialysis sessions to manage her symptoms. Five months after switching to a frequent and extended home HD regime, we observed a tremendous improvement in her health and well-being, with complete reversal of her cardiac dysfunction.

CONCLUSIONS

Home HD is a practically viable option in children with severe cardiac dysfunction. Gentler, more intensive dialysis will draw out and improve the ureamic component of heart disease. This may translate into improved cardiac function.

Role of Drug Metabolism in the Cytotoxicity and Clinical Efficacy of Anthracyclines

Many clinical studies involving anti-tumor agents neglect to consider how these agents are metabolized within the host and whether the creation of specific metabolites alters drug therapeutic properties or toxic side effects. However, this is not the case for the anthracycline class of chemotherapy drugs. This review describes the various enzymes involved in the one electron (semi-quinone) or two electron (hydroxylation) reduction of anthracyclines, or in their reductive deglycosidation into deoxyaglycones. The effects of these reductions on drug antitumor efficacy and toxic side effects are also discussed. Current evidence suggests that the one electron reduction of anthracyclines augments both their tumor toxicity and their toxicity towards the host, in particular their cardiotoxicity. In contrast, the two electron reduction (hydroxylation) of anthracyclines strongly reduces their ability to kill tumor cells, while augmenting cardiotoxicity through their accumulation within cardiomyocytes and their direct effects on excitation/contraction coupling within the myocytes. The reductive deglycosidation of anthracyclines appears to inactivate the drug and only occurs under rare, anaerobic conditions. This knowledge has resulted in the identification of important new approaches to improve the therapeutic index of anthracyclines, in particular by inhibiting their cardiotoxicity. The true utility of these approaches in the management of cancer patients undergoing anthracycline-based chemotherapy remains unclear, although one such agent (the iron chelator dexrazoxane) has recently been approved for clinical use.

Frailty in childhood cancer survivors

Young adult childhood cancer survivors are at an increased risk of frailty, a physiologic phenotype typically found among older adults. This phenotype is associated with new-onset chronic health conditions and mortality among both older adults and childhood cancer survivors. Mounting evidence suggests that poor fitness, muscular weakness, and cognitive decline are common among adults treated for childhood malignancies, and that risk factors for these outcomes are not limited to those treated with cranial radiation. Although the pathobiology of this phenotype is not known, early cellular senescence, sterile inflammation, and mitochondrial dysfunction in response to initial cancer or treatment-related insults are hypothesized to play a role. To the authors' knowledge, interventions to prevent or remediate frailty among childhood cancer survivors have not been tested to date. Pharmaceutical, nutraceutical, and lifestyle interventions have demonstrated some promise.

Biodegradable microparticles loaded with doxorubicin and CpG ODN for in situ immunization against cancer

In situ immunization is based on the concept that it is possible to break immune tolerance by inducing tumor cell death in situ in a manner that provides antigen-presenting cells such as dendritic cells (DCs) with a wide selection of tumor antigens that can then be presented to the immune system and result in a therapeutic anticancer immune response. We designed a comprehensive approach to in situ immunization using poly(lactic-co-glycolic acid) (PLGA)-biodegradable microparticles (MPs) loaded with doxorubicin (Dox) and CpG oligodeoxynucleotides (CpG) that deliver Dox (chemotherapy) and CpG (immunotherapy) in a sustained-release fashion when injected intratumorally. Dox induces immunogenic tumor cell death while CpG enhances tumor antigen presentation by DCs. PLGA MPs allow their safe co-delivery while evading the vesicant action of Dox. In vitro, we show that Dox/CpG MPs can kill B and T lymphoma cells and are less toxic to DCs. In vivo, Dox/CpG MPs combined with antibody therapy to enhance and maintain the T cell response generated systemic immune responses that suppressed injected and distant tumors in a murine B lymphoma model, leading to tumor-free mice. The combination regimen was also effective at reducing T cell lymphoma and melanoma tumor burdens. In conclusion, Dox/CpG MPs represent an efficient and safe tool for in situ immunization that could provide a promising component of immunotherapy for patients with a variety of types of cancer.

Aneugenic effects of epirubicin in somatic and germinal cells of male mice

The ability of the antineoplastic agent epirubicin to induce aneuploidy and meiotic delay in the somatic and germinal cells of male mice was investigated by fluorescence in situ hybridization assay using labeled DNA probes and BrdU-incorporation assay. Mitomycin C and colchicine were used as positive controls for clastogen and aneugen, respectively, and these compounds produced the expected responses. The fluorescence in situ hybridization assay with a centromeric DNA probe for erythrocyte micronuclei showed that epirubicin is not only clastogenic but also aneugenic in somatic cells in vivo. By using the BrdU-incorporation assay, it could be shown that the meiotic delay caused by epirubicin in germ cells was approximately 48 h. Disomic and diploid sperm were shown in epididymal sperm hybridized with DNA probes specific for chromosomes 8, X and Y after epirubicin treatment. The observation that XX- and YY-sperm significantly prevailed over XY-sperm indicates missegregation during the second meiotic division. The results also suggest that earlier prophase stages contribute less to epirubicin-induced aneuploidy. Both the clastogenic and aneugenic potential of epirubicin can give rise to the development of secondary tumors and abnormal reproductive outcomes in cured cancer patients and medical personnel exposed to epirubicin.

Microfluidic remote loading for rapid single-step liposomal drug preparation

Microfluidic-directed formation of liposomes is combined with in-line sample purification and remote drug loading for single step, continuous-flow synthesis of nanoscale vesicles containing high concentrations of stably loaded drug compounds. Using an on-chip microdialysis element, the system enables rapid formation of large transmembrane pH and ion gradients, followed by immediate introduction of amphipathic drug for real-time remote loading into the liposomes. The microfluidic process enables in-line formation of drug-laden liposomes with drug : lipid molar ratios of up to 1.3, and a total on-chip residence time of approximately 3 min, representing a significant improvement over conventional bulk-scale methods which require hours to days for combined liposome synthesis and remote drug loading. The microfluidic platform may be further optimized to support real-time generation of purified liposomal drug formulations with high concentrations of drugs and minimal reagent waste for effective liposomal drug preparation at or near the point of care.

Quantification of doxorubicin in biofluids using white light excitation fluorescence

A fiber optic spectrometer setup was designed for white light excitation fluorescence 'WLEF' based measurements. Using this setup, two different analytical methods, a self referencing ratio-metric and a difference WLEF methods, were developed for the quantification of doxorubicin (DXR) in biofluids. It was seen that Acetonitrile (ACN) acts as an efficient and transparent extracting medium for DXR. The figures of merit and the percent recoveries of DXR in blood serum, even in presence of external fluorophores and in urine samples are comparable with existing analytical methods. The compact spectrometer is expected to be useful for easy quantification of fluorescent pharmaceuticals in biofluids.

CDK4 inhibition and doxorubicin mediate breast cancer cell apoptosis through Smad3 and survivin

Cyclin D1/CDK4 activity is upregulated in up to 50% of breast cancers and CDK4-mediated phosphorylation negatively regulates the TGFβ superfamily member Smad3. We sought to determine if CDK4 inhibition and doxorubicin chemotherapy could impact Smad3-mediated cell/colony growth and apoptosis in breast cancer cells. Parental and cyclin D1-overexpressing MCF7 cells were treated with CDK4 inhibitor, doxorubicin, or combination therapy and cell proliferation, apoptosis, colony formation, and expression of apoptotic proteins were evaluated using an MTS assay, TUNEL staining, 3D Matrigel assay, and apoptosis array/immunoblotting. Study cells were also transduced with WT Smad3 or a Smad3 construct resistant to CDK4 phosphorylation (5M) and colony formation and expression of apoptotic proteins were assessed. Treatment with CDK4 inhibitor/doxorubicin combination therapy, or transduction with 5M Smad3, resulted in a similar decrease in colony formation. Treating cyclin D overexpressing breast cancer cells with combination therapy also resulted in the greatest increase in apoptosis, resulted in decreased expression of anti-apoptotic proteins survivin and XIAP, and impacted subcellular localization of pro-apoptotic Smac/DIABLO. Additionally, transduction of 5M Smad3 and doxorubicin treatment resulted in the greatest change in apoptotic protein expression. Collectively, this work showed the impact of CDK4 inhibitor-mediated, Smad3-regulated tumor suppression, which was augmented in doxorubicin-treated cyclin D-overexpressing study cells.

In situ proliferation contributes to accumulation of tumor-associated macrophages in spontaneous mammary tumors

Infiltration of a neoplasm with tumor-associated macrophages (TAMs) is considered an important negative prognostic factor and is functionally associated with tumor vascularization, accelerated growth, and dissemination. However, the ontogeny and differentiation pathways of TAMs are only incompletely characterized. Here, we report that intense local proliferation of fully differentiated macrophages rather than low-pace recruitment of blood-borne precursors drives TAM accumulation in a mouse model of spontaneous mammary carcinogenesis, the MMTVneu strain. TAM differentiation and expansion is regulated by CSF1, whose expression is directly controlled by STAT1 at the gene promoter level. These findings appear to be also relevant for human breast cancer, in which an interrelationship between STAT1, CSF1, and macrophage marker expression was identified. We propose that, akin to various MU subtypes in nonmalignant tissues, local proliferation and CSF1 play a vital role in the homeostasis of TAMs.

Synergistic dual-ligand doxorubicin liposomes improve targeting and therapeutic efficacy of brain glioma in animals

Therapeutic outcome for the treatment of glioma was often limited due to low permeability of delivery systems across the blood-brain barrier (BBB) and poor penetration into the tumor tissue. In order to overcome these hurdles, we developed the dual-targeting doxorubicin liposomes conjugated with cell-penetrating peptide (TAT) and transferrin (T7) (DOX-T7-TAT-LIP) for transporting drugs across the BBB, then targeting brain glioma, and penetrating into the tumor. The dual-targeting effects were evaluated by both in vitro and in vivo experiments. In vitro cellular uptake and three-dimensional tumor spheroid penetration studies demonstrated that the system could not only target endothelial and tumor monolayer cells but also penetrate tumor to reach the core of the tumor spheroids and inhibit the growth of the tumor spheroids. In vivo imaging further demonstrated that T7-TAT-LIP provided the highest tumor distribution. The median survival time of tumor-bearing mice after administering DOX-T7-TAT-LIP was significantly longer than those of the single-ligand doxorubicin liposomes and free doxorubicin. In conclusion, the dual-ligand liposomes comodified with T7 and TAT possessed strong capability of synergistic targeted delivery of payload into tumor cells both in vitro and in vivo, and they were able to improve the therapeutic efficacy of brain glioma in animals.

Synergistic nanoparticulate drug combination overcomes multidrug resistance, increases efficacy, and reduces cardiotoxicity in a nonimmunocompromised breast tumor model

Anthracyclines, commonly employed for cancer chemotherapy, suffer from dose-limiting cardiotoxicity and poor efficacy due to multidrug resistance (MDR). We previously demonstrated that simultaneous delivery of the synergistic drugs doxorubicin (DOX) and mitomycin C (MMC) by polymer-lipid hybrid nanoparticles (PLN) circumvented MDR, increased efficacy, and reduced cardiotoxicity in immuncompromised mice superior to poly(ethylene glycol)-coated (PEGylated) lipososmal DOX (PLD). Herein it is shown that the DOX-MMC combination was also synergistic in MDR EMT6/AR1 murine breast cancer cells and that their nanoparticle formulations were able to overcome the MDR phenotype. In contrast PLD exhibited little or no effect on the MDR cells. For the first time, these differences in in vitro efficacy are shown to be strongly correlated with cellular uptake and intracellular distribution of DOX brought about by DOX formulations (e.g., free solution, PLN vs PLD). To take into consideration the role of an intact immune system and tumor stroma in the response of host and tumor to chemotherapy, use was made of nonimmunocomprised mouse models to study the dose tolerance, cardiotoxicity, and efficacy of DOX-MMC coloaded PLN (DMsPLN) compared to PLD. DMsPLN treatment at 50 mg/m(2) DOX and 17 mg/m(2) of MMC singly or once every 4 days for 4 cycles were well tolerated by the mice without elevated systemic toxicity blood markers or myocardial damage. In contrast, PLD was limited to a single treatment due to significant total weight loss. The DMsPLN treatment delayed tumor growth up to 312% and 28% in EMT6/WT and EMT6/AR1 models, respectively. This work supports the translational value of DMsPLN for the aggressive management of either naïve or anthracycline-resistant tumors.

The influence of pH and temperature on the stability of N-[(piperidine)methylene]daunorubicin Hydrochloride and a comparison of the stability of daunorubicin and its four new amidine derivatives in aqueous solutions

The influence of pH and temperature on the stability of N-[(piperidine)methylene]daunorubicin hydrochloride (PPD) was investigated. Degradation was studied using an HPLC method. Specific acid-base catalysis of PPD involves hydrolysis of protonated molecules of PPD catalyzed by hydrogen ions and spontaneous hydrolysis under the influence of water zwitterions, unprotonated molecules, and monoanions of PPD. The thermodynamic parameters of these reactions, energy, enthalpy, and entropy, were calculated. Also, the stability of daunorubicin and its new amidine derivatives (piperidine, morpholine, pyrrolidine, and hexahydroazepin-1-yl) in aqueous solutions was compared and discussed.

Validation and clinical evaluation of a UHPLC method with fluorescence detector for plasma quantification of doxorubicin and doxorubicinol in haematological patients

A rapid and simple UHPLC-fluorescence detection method for the quantification of doxorubicin and its main metabolite, doxorubicinol, in human plasma has been developed. The method was also validated for its application in therapeutic drug monitoring, a clinical approach used in the optimization of oncologic treatments. Following a single protein precipitation step, chromatographic separation was achieved using a C18 column (50mm×2.10mm, particle size 1.7μm) at 50°C with a mobile phase consisting of water (containing 0.4% triethylamine and 0.4% orthophosphoric acid)/acetonitrile (77:23, v/v). Flow rate was 0.50mL/min and fluorescence detection with an excitation wavelength of 470nm and an emission wavelength of 548nm was used. The method met the specifications of linearity, selectivity, sensitivity, accuracy, precision and stability of the FDA and EMA guidelines for the validation of bioanalytical methods. Linearity for the drug (8-3000ng/mL) and the metabolite (3-150ng/mL) was observed (R(2)>0.992) and the maximum intra-day and inter-day precision coefficients of variation were less than 14% for both. The lower limits of quantification were 8 and 3ng/mL for doxorubicin and doxorubicinol, respectively. The method was successfully applied to the quantify plasma concentrations of doxorubicin and doxorubicinol in 33 patients diagnosed with haematological malignancies in which broad ranges for drug (8.3-2766.0ng/mL) and metabolite (4.8-104.9ng/mL) levels were measured adequately.

Monitoring subcellular biotransformation of N-L-leucyldoxorubicin by micellar electrokinetic capillary chromatography coupled to laser-induced fluorescence detection

Development of prodrugs is a promising alternative to address cytotoxicity and nonspecificity of common anticancer agents. N-L-leucyldoxorubicin (LeuDox) is a prodrug that is biotransformed to the anticancer drug doxorubicin (Dox) in the extracellular space; however, its biotransformation may also occur intracellularly in endocytic organelles. Such organelle-specific biotransformation is yet to be determined. In this study, magnetically enriched endocytic organelle fractions from human uterine sarcoma cells were treated with LeuDox. Micellar electrokinetic chromatography with laser-induced fluorescence detection (MEKC-LIF) was used to determine that 10% of LeuDox was biotransformed to Dox, accounting for ~43% of the biotransformation occurring in the post-nuclear fraction. This finding suggests that endocytic organelles also participate in the intracellular biotransformation of LeuDox to Dox.

Assessment of early-onset chronic progressive anthracycline cardiotoxicity in children: different response patterns of right and left ventricles

We aimed to assess early-onset chronic progressive cardiotoxicity in the left and right ventricles with increasing cumulative anthracycline doses. We evaluated 72 patients within the first year after doxorubicin and/or daunorubicin treatment (median 1.3 months; range 0.3-11.5) and 31 healthy controls. Pretreatment and posttreatment QT interval analyzes were performed in 27 newly diagnosed patients. The echocardiographic data of all examinations of 72 patients were classified into three groups according to instant cumulative anthracycline doses: treatment group (TG)-I (≤120 mg/m(2); n = 26), TG-II (120-240 mg/m(2); n = 39), and TG-III (≥240 mg/m(2); n = 40). Diastolic and systolic parameters were analyzed by conventional echocardiography and tissue Doppler imaging (TDI) and compared with those of healthy controls. The mean age for patients and controls was 8.2 ± 4.5 and 9.6 ± 4.2 years, respectively (p > 0.05). QTc dispersion significantly increased after anthracycline treatment (p = 0.02). TDI showed decreased E' velocity (p < 0.001) and E'/A' ratio (p < 0.001) at lateral tricuspid annulus segment in TG-I, and these findings continued in TG-II and -III. In addition, S' velocity decreased in TG-I, -II, and -III at lateral mitral annulus (10.5 ± 2.6 cm/s, p < 0.05; 9.9 ± 2.2 cm/s, p < 0.001; and 10.1 ± 2.3 cm/s, p < 0.01, respectively). However, decrease in left-ventricular ejection fraction was statistically significant in TG-II and -III (p < 0.001). Although myocardial performance index was significantly increased in all treatment groups in both segments, it was primarily due to significant increases in isovolumic relaxation time at the lateral tricuspid annulus and isovolumic contraction time at the lateral mitral annulus. Abnormalities in diastolic function in right ventricle and systolic function in the left ventricle were observed even with a cumulative anthracycline dose <120 mg/m(2) by TDI. In addition, anthracycline treatment led to an increase in QTc dispersion.

Role of size of drug delivery carriers for pulmonary and intravenous administration with emphasis on cancer therapeutics and lung-targeted drug delivery

The design of a drug delivery system and the fabrication of efficient, successful, and targeted drug carriers are two separate issues that require slightly different design parameters.

Quantitative subcellular study of transferrin receptor-targeted doxorubicin and its metabolite in human breast cancer cells

The extended use of doxorubicin (DOX) could be limited due to the emergence of drug resistance and cardiotoxicity associated with its treatment. Conjugates of DOX with transferrin (DOX-TRF) can effectively alleviate these side effects, thereby leading to a better treatment. The effectiveness of DOX-TRF could result from the enhancement of transferrin receptor (TfR)-mediated transportation. However, detailed TfR-mediated DOX delivery has not been fully elucidated thus far, which may rely on the quantitative subcellular study of DOX distribution and metabolism. In this study, an immunoisolation assay was developed to isolate the organelles with high purity, yield and integrity. Using this immunoisolation assay together with liquid chromatography-tandem mass spectrometry (LC/MS/MS), the subcellular distribution profiles of DOX and its main metabolite doxorubicinol (DOXol) in human breast cancer cells MCF-7/WT and MCF-7/ADR were determined and compared after the treatment of DOX and DOX-TRF. As expected, DOX-TRF treated cells have a higher drug accumulation compared to DOX treated cells. DOX-TRF was predominantly cytoplasmic. In addition, TfR-mediated transportation had a significant impact on the transformation of DOX to DOXol in the cells. This study provided the evidence that immunoisolation together with LC/MS/MS is an effective technique in subcellular investigations.

Administration of chromium(III) and manganese(II) as a potential protective approach against daunorubicin-induced cardiotoxicity: in vitro and in vivo experimental evidence

Daunorubicin (DNR) is a widely used antitumor drug, but its application is limited because of its cardiotoxic side effects. The present study was designed to investigate the interaction between DNR and cardiac myosin (CM) in the presence of chromium(III) (Cr(3+)) and manganese(II) (Mn(2+)) using fluorescence spectrometry under simulative physiological conditions with the aim of exploring the influence of metal ion on DNR-CM complex and finding out an aggressive approach to abrogate of DNR-induced cardiotoxicity. In detail, the quenching and binding constant of ternary system, including metal ion, DNR, and CM, were measured and compared with the DNR-CM. The data from in vitro experiments indicate that the presence of Cr(3+) or Mn(2+) distinctly decreased the binding force between DNR and CM, and alleviated the cardiac toxicity caused by DNR. In addition, the variations in mice body weight and myocardial enzyme level were examined by in vivo experiments. Animals receiving Cr(3+) or Mn(2+) supplementation of DNR showed preservation of the normal pattern of the heart, especially 2.0 mg Cr(3+)/kg body wt or 50.0 mg Mn(2+)/kg body wt exhibited an obviously protective effect accompanied with body weight raise when compared with the mice treated with DNR alone, decreased the ratio of heart to body weight (BW) and the ratio of left ventricular mass to BW to the normal levels, and inhibited the leak of myocardial enzyme caused by DNR. As a result, this study suggests that pretreatment of lower dose of Cr(3+) (2 mg/kg wt) and moderate dose of Mn(2+) (50 mg/kg wt) might be useful and play an important role in ameliorating the cardiotoxicity of DNR treatment in cancer patients.

siRNA-mediated knock-down of DFF45 amplifies doxorubicin therapeutic effects in breast cancer cells

PURPOSE

RNA interference (RNAi) has become a promising tool for cancer therapy. Small interfering RNAs (siRNAs) can synergistically enhance the cell killing effects of drugs used in cancer treatment. Here we examined the effects of siRNA-mediated DNA fragmentation factor 45 (DFF45) gene silencing on breast cancer cell viability, cell cycle arrest, and apoptosis in the presence and absence of doxorubicin.

METHODS

We designed three siRNAs, which target different regions of the DFF45 mRNA. Gene silencing was confirmed by real time RT-PCR and Western blot analyses. The impact of DFF45 siRNA, doxorubicin, and their combination on the viability, cell cycle and apoptosis of T-47D and MDA-MB-231 breast cancer cells were determined by MTT, PI staining, annexin V binding, caspase-3 activity, DNA laddering, and chromatin condensation assays.

RESULTS

Based on flow cytometric analyses, we found that silencing of DFF45 alone had little effect on apoptosis, especially in T-47D cells. However, when used in combination with doxorubicin (0.33 μM) a significant increase (P < 0.05) in apoptosis was observed in T-47D and MDA-MB-231 cells, i.e., ~2.5- and 3-fold, respectively. Caspase-3 activity, chromatin condensation, as well as DNA laddering supported increased apoptosis in the combinatorial treatment. Cell cycle arrest in both cell lines occurred at lower levels after siRNA + doxorubicin treatment compared to doxorubicin only.

CONCLUSIONS

Our data indicate that DFF45 gene silencing, when applied in combination with doxorubicin, may offer a novel therapeutic strategy for the treatment of breast cancer.

An ultrasensitive high throughput screen for DNA methyltransferase 1-targeted molecular probes

DNA methyltransferase 1 (DNMT1) is the enzyme most responsible for epigenetic modification of human DNA and the intended target of approved cancer drugs such as 5-aza-cytidine and 5-aza-2'-deoxycytidine. 5-aza nucleosides have complex mechanisms of action that require incorporation into DNA, and covalent trapping and proteolysis of DNMT isozymes. Direct DNMT inhibitors are needed to refine understanding of the role of specific DNMT isozymes in cancer etiology and, potentially, to improve cancer prevention and treatment. Here, we developed a high throughput pipeline for identification of direct DNMT1 inhibitors. The components of this screen include an activated form of DNMT1, a restriction enzyme-coupled fluorigenic assay performed in 384 well plates with a z-factor of 0.66, a counter screen against the restriction enzyme, a screen to eliminate DNA intercalators, and a differential scanning fluorimetry assay to validate direct binders. Using the Microsource Spectrum collection of 2320 compounds, this screen identified nine compounds with dose responses ranging from 300 nM to 11 µM, representing at least two different pharmacophores with DNMT1 inhibitory activity. Seven of nine inhibitors identified exhibited two to four-fold selectivity for DNMT1 versus DNMT3A.

Radiation sterilization of anthracycline antibiotics in solid state

The impact of ionizing radiation generated by a beam of electrons of 25-400 kGy on the stability of such analogs of anthracycline antibiotics as daunorubicin (DAU), doxorubicin (DOX), and epidoxorubicin (EPI) was studied. Based on EPR results, it was established that unstable free radicals decay exponentially with the half-time of 4 days in DAU and DOX and 7 days in EPI after irradiation. Radiation-induced structural changes were analyzed with the use of spectrophotometric methods (UV-Vis and IR) and electron microscope imaging (SEM). A chromatographic method (HPLC-DAD) was applied to assess changes in the contents of the analogs in the presence of their impurities. The study showed that the structures of the analogs did not demonstrate any significant alterations at the end of the period necessary for the elimination of unstable free radicals. The separation of main substances and related substances (impurities and potential degradation products) allowed determining that no statistically significant changes in the content of particular active substances occurred and that their conversion due to the presence of free radicals resulting from exposure to an irradiation of 25 kGy (prescribed to ensure sterility) was not observed.

Cardiac expression of human type 2 iodothyronine deiodinase increases glucose metabolism and protects against doxorubicin-induced cardiac dysfunction in male mice

Altered glucose metabolism in the heart is an important characteristic of cardiovascular and metabolic disease. Because thyroid hormones have major effects on peripheral metabolism, we examined the metabolic effects of heart-selective increase in T3 using transgenic mice expressing human type 2 iodothyronine deiodinase (D2) under the control of the α-myosin heavy chain promoter (MHC-D2). Hyperinsulinemic-euglycemic clamps showed normal whole-body glucose disposal but increased hepatic insulin action in MHC-D2 mice as compared to wild-type (WT) littermates. Insulin-stimulated glucose uptake in heart was not altered, but basal myocardial glucose metabolism was increased by more than two-fold in MHC-D2 mice. Myocardial lipid levels were also elevated in MHC-D2 mice, suggesting an overall up-regulation of cardiac metabolism in these mice. The effects of doxorubicin (DOX) treatment on cardiac function and structure were examined using M-mode echocardiography. DOX treatment caused a significant reduction in ventricular fractional shortening and resulted in more than 50% death in WT mice. In contrast, MHC-D2 mice showed increased survival rate after DOX treatment, and this was associated with a six-fold increase in myocardial glucose metabolism and improved cardiac function. Myocardial activity and expression of AMPK, GLUT1, and Akt were also elevated in MHC-D2 and WT mice following DOX treatment. Thus, our findings indicate an important role of thyroid hormone in cardiac metabolism and further suggest a protective role of glucose utilization in DOX-mediated cardiac dysfunction.

Pixantrone: merging safety with efficacy

Pixantrone is a novel anthracycline derivative, manufactured by Cell Therapeutics Incorporated, WA, USA. It was developed with the aim to retain the efficacy of anthracyclines and be less cardiotoxic. Initial safety trials and single-arm, Phase II trials have shown preliminary evidence of anticancer activity and manageable toxicity. These results were validated in multicenter, randomized clinical trials where pixantrone was used as single agent or in combination with other cytotoxics. Following the results of PIX301, it is now approved by the EMA for use as monotherapy in pretreated patients with refractory non-Hodgkin lymphomas. Ongoing trials are assessing the use of pixantrone in combination with other drugs.

Sticky siRNAs targeting survivin and cyclin B1 exert an antitumoral effect on melanoma subcutaneous xenografts and lung metastases

Background

Melanoma represents one of the most aggressive and therapeutically challenging malignancies as it often gives rise to metastases and develops resistance to classical chemotherapeutic agents. Although diverse therapies have been generated, no major improvement of the patient prognosis has been noticed. One promising alternative to the conventional therapeutic approaches currently available is the inactivation of proteins essential for survival and/or progression of melanomas by means of RNA interference. Survivin and cyclin B1, both involved in cell survival and proliferation and frequently deregulated in human cancers, are good candidate target genes for siRNA mediated therapeutics.

Methods

We used our newly developed sticky siRNA-based technology delivered with linear polyethyleneimine (PEI) to inhibit the expression of survivin and cyclin B1 both in vitro and in vivo, and addressed the effect of this inhibition on B16-F10 murine melanoma tumor development.

Results

We confirm that survivin and cyclin B1 downregulation through a RNA interference mechanism induces a blockage of the cell cycle as well as impaired proliferation of B16-F10 cells in vitro. Most importantly, PEI-mediated systemic delivery of sticky siRNAs against survivin and cyclin B1 efficiently blocks growth of established subcutaneaous B16-F10 tumors as well as formation and dissemination of melanoma lung metastases. In addition, we highlight that inhibition of survivin expression increases the effect of doxorubicin on lung B16-F10 metastasis growth inhibition.

Conclusion

PEI-mediated delivery of sticky siRNAs targeting genes involved in tumor progression such as survivin and cyclin B1, either alone or in combination with chemotherapeutic drugs, represents a promising strategy for melanoma treatment.

Enhancing the Effects of Low Dose Doxorubicin Treatment by the Radiation in T47D and SKBR3 Breast Cancer Cells

Purpose

Breast cancer is the most common malignancy of women worldwide. Radiotherapy consists of a vital element in the treatment of breast cancer but relative side effects and different radioactive responses are limiting factors for a successful treatment. Doxorubicin has been used to treat cancers for over 30 years and is considered as the most effective drug in the treatment of breast cancer. There are also many chronic side effects that limit the amount of doxorubicin that can be administered. The combined radio-drug treatment, with low doses, can be an approach for reducing side effects from single modality treatments instead of suitable cure rates.

Methods

We have studied the effect of 1, 1.5, and 2 Gy doses of 9 MV X-rays along with 1 µM doxorubicin on inducing cell death, apoptosis and also p53 and PTEN gene expression in T47D and SKBR3 breast cancer cells.

Results

Doxorubicin treatment resulted in upregulation of radiation-induced levels of p53 and downregulation of PTEN at 1 and 1.5 Gy in T47D breast cancer cells, as well as downregulation of p53 mRNA level of expression and upregulation of PTEN mRNA level of expression in SKBR3 breast cancer cell line. In addition, doxorubicin in combination with radiation decreased the viability of breast cancer cell lines in the both cell lines.

Conclusion

Low doses of doxorubicin, with least cell toxicity, may be an effective treatment for breast cancer when used in conjunction with ionizing radiation.

Biocompatibility, absorption and safety of protein nanoparticle-based delivery of doxorubicin through oral administration in rats

Doxorubicin, a potent anticancer drug associated with cardiotoxicity and low oral bioavailability, was loaded into apotransferrin nanoparticles to improve its pharmacological performance. Here, doxorubicin (doxo)-loaded apotransferrin nanoparticles were termed as Apodoxonano, and they were prepared by sol-oil chemistry. The pH-dependent stability of nanoparticles in simulated fluids was evaluated, and the in vitro release was investigated in phosphate-buffered saline. The pharmacokinetic and toxicity studies were conducted in Wistar rats. Nanoparticles have an average size of 75 nm, with 63% entrapment efficiency, at 10 mg w/w of apotransferrin. The particles displayed good pH-dependent stability in the pH range 1.1-7.4, but sensitive at endosomal pH of 5.5, thus facilitating intracellular drug release in endosomes. Multiplex assay showed high transport ability of nano form across epithelial cells (caco-2) when compared to doxo. Moreover, during oral administration, Apodoxonano localizes significantly in esophagus, stomach and small intestine, suggesting that it was absorbed in GI tract through epithelial lining. The drug localization was shown to be significantly lower in the heart reflecting its decreased cardiotoxic nature. The Apodoxonano with a longer bioavailability and a negligible cardiotoxicity can serve as an effective and safe vehicle of drug delivery.

Combined modality doxorubicin-based chemotherapy and chitosan-mediated p53 gene therapy using double-walled microspheres for treatment of human hepatocellular carcinoma

The therapeutic efficiency of combined chemotherapy and gene therapy on human hepatocellular carcinoma HepG2 cells was investigated using double-walled microspheres that consisted of a poly(D,L-lactic-co-glycolic acid) (PLGA) core surrounded by a poly(L-lactic acid) (PLLA) shell layer and fabricated via the precision particle fabrication (PPF) technique. Here, double-walled microspheres were used to deliver doxorubicin (Dox) and/or chitosan-DNA nanoparticles containing the gene encoding the p53 tumor suppressor protein (chi-p53), loaded in the core and shell phases, respectively. Preliminary studies on chi-DNA nanoparticles were performed to optimize gene transfer to HepG2 cells. The transfection efficiency of chi-DNA nanoparticles was optimal at an N/P ratio of 7. In comparison to the 25-kDa branched polyethylenimine (PEI), chitosan showed no inherent toxicity towards the cells. Next, the therapeutic efficiencies of Dox and/or chi-p53 in microsphere formulations were compared to free drug(s) and evaluated in terms of growth inhibition, and cellular expression of tumor suppressor p53 and apoptotic caspase 3 proteins. Overall, the combined Dox and chi-p53 treatment exhibited enhanced cytotoxicity as compared to either Dox or chi-p53 treatments alone. Moreover, the antiproliferative effect was more substantial when cells were treated with microspheres than those treated with free drugs. High p53 expression was maintained during a five-day period, and was largely due to the controlled and sustained release of the microspheres. Moreover, increased activation of caspase 3 was observed, and was likely to have been facilitated by high levels of p53 expression. Overall, double-walled microspheres present a promising dual anticancer delivery system for combined chemotherapy and gene therapy.

Comparison of Cardiac Troponin I and T, Including the Evaluation of an Ultrasensitive Assay, as Indicators of Doxorubicin-induced Cardiotoxicity

Cardiac troponin (cTn) has been utilized to assess acute myocardial injury, but the cTn response in active/ongoing chronic injury is not well documented. The purpose of this study was to characterize the cardiac troponin I (cTnI), cardiac troponin T (cTnT), high-sensitivity cTnI, hematology, and clinical chemistry responses in rats treated with doxorubicin. Rats treated with 1, 2, or 3 mg/kg/week (wk) of doxorubicin for 2, 4, or 6 wks were sacrificed after 0, 2, or 4 wks of recovery and compared to untreated controls and animals treated with doxorubicin/dexrazoxane (50 mg/kg/wk) or etoposide (1 and 3 mg/kg/wk). The incidence and mean magnitude of cTn response increased with increasing dose and/or duration of doxorubicin treatment. Conversely, dexrazoxane/doxorubicin was partially protective for cardiotoxicity, and minimal cardiotoxicity occurred with etoposide treatment. Both cTnI and cTnT effectively identified doxorubicin-induced injury as indicated by vacuolation of cardiomyocytes of the atria/ventricles. The association between the cTn responses and histological changes was greater at the higher total exposures, but the magnitude of cTn response did not match closely with histologic grade. The high-sensitivity cTnI assay was also effective in identifying cardiac injury. Alterations occurred in the hematology and clinical chemistry parameters and reflected both dose and duration of doxorubicin treatment.

Rhodomycin analogues from Streptomyces purpurascens: isolation, characterization and biological activities

During a screening program for bioactive natural products, a potential Streptomyces sp was isolated from soil. On the basis of biochemical, cultural, physiological and 16S rRNA gene analysis, it was identified as Streptomyces purpurascens. The isolate was grown in liquid medium and the crude antibiotic complex was obtained by ethyl acetate extraction. Seven purified fractions were obtained by preparative Thin Layer Chromatography (TLC). Acid hydrolysis of each fraction and subsequent TLC led to the identification of aglycones and sugars indicating these compounds to be Rhodomycin and its analogues. The identity of these compounds was established on the basis of UV-visible and FT-IR spectra and comparison with published data. The compounds were active against Gram-positive bacteria. Compound E, identified as Rhodomycin B, was found to be the most potent compound with an MIC of 2 μg/ml against Bacillus subtilis. Compounds A and F identified as α2-Rhodomycin II and Obelmycin respectively, and Compound E exhibited an IC50 of 8.8 μg/ml against HeLa cell line but no cytotoxicity was found against L929.