Anthracyclines in the treatment of cancer. An overview

2-Deoxyglycosyl 3-benzoylpropionates as novel donors for the direct and stereoselective synthesis of 2-deoxy-glycosides

Lewis acid mediated stereoselective synthesis of 2-deoxy-O-glycosides has been demonstrated using 2-deoxyglycosyl 3-benzoylpropionates as novel glycosyl donors.

Out of the frying pan and into the fire: damage-associated molecular patterns and cardiovascular toxicity following cancer therapy

Cardio-oncology is a new and rapidly expanding field that merges cancer and cardiovascular disease. Cardiovascular disease is an omnipresent side effect of cancer therapy; in fact, it is the second leading cause of death in cancer survivors after recurrent cancer. It has been well documented that many cancer chemotherapeutic agents cause cardiovascular toxicity. Nonetheless, the underlying cause of cancer therapy-induced cardiovascular toxicity is largely unknown. In this review, we discuss the potential role of damage-associated molecular patterns (DAMPs) as an underlying contributor to cancer therapy-induced cardiovascular toxicity. With an increasing number of cancer patients, as well as extended life expectancy, understanding the mechanisms underlying cancer therapy-induced cardiovascular disease is of the utmost importance to ensure that cancer is the only disease burden that cancer survivors have to endure.

Synergistic dual-modified liposome improves targeting and therapeutic efficacy of bone metastasis from breast cancer

Breast cancer frequently metastasizes to bone, where it leads to poor clinical prognosis. Due to the peculiarity of the bone microstructure, the uptake of drugs often happens at non-targeted sites, which produces a similar cytotoxicity in both cancerous and healthy cells. In this study, a rational strategy was implemented to take advantage of a combination of both an octapeptide with eight repeating sequences of aspartate (Asp8) and folate to create a more selective and efficient drug delivery system to target cancer cells in bone tissue. Asp8 and folate were conjugated to the distal ends of DSPE-PEG2000-maleimide and DSPE-PEG2000-amine to create DSPE-PEG2000-Asp8 and DSPE-PEG2000-Folate, respectively, which were incorporated onto the surface of a doxorubicin (DOX)-loaded liposomes (A/F-LS). Asp8, similar to the hydroxyapatite-binding domains of osteopontin and osteocalcin, has been used as bone-targeting moieties for exclusive delivery of drugs to bone. The folate moiety binds selectively to folate receptor-positive tumors. The dual-targeting effects were evaluated by both in vitro and in vivo experiments. By taking advantages of dual-targeting drug delivery, the dual-modified liposomal drug system could relieve pain and improve survival. Inspired by its enhanced therapeutic efficacy and low toxicity, DOX-loaded A/F-LS could serve as an effective drug system for targeted therapy of bone metastases.

Substrate Scope of O-Methyltransferase from Streptomyces peucetius for Biosynthesis of Diverse Natural Products Methoxides

Methylation is a common post-modification reaction that is observed during the biosynthesis of secondary metabolites produced by plants and microorganisms. Based on the sequence information from Streptomyces peucetius ATCC27952, a putative O-methyltransferase (OMT) gene SpOMT7740 was polymerase chain reaction amplified and cloned into E. coli BL21 (DE3) host to test the substrate promiscuity and conduct functional characterization. In vitro and in vivo reaction assays were carried out over various classes of substrates: flavonoids (flavonol, flavones, and isoflavonoid), chalcones, anthraquinones, anthracyclines, and sterol molecules, and the applications in synthesizing diverse classes of O-methoxy natural products were also illustrated. SpOMT7740 catalyzed the O-methylation reaction to form various natural and non-natural O-methoxides, includes 7-hydroxy-8-O-methoxy flavone, 3-O-methoxy flavone, three mono-, di-, and tri-O-methoxy genistein, mono-O-methoxy phloretin, mono-O-methoxy luteolin, 3-O-methoxy β-sitosterol, and O-methoxy anthraquinones (emodin and aloe emodin) and O-methoxy anthracycline (daunorubicin) exhibiting diverse substrate flexibility. Daunorubicin is a native secondary metabolite of S. peucetius. Among the compounds tested, 7,8-dihydroxyflavone was the best substrate for bioconversion to 7-hydroxy-8-O-methoxy flavone, and it was structurally elucidated. This enzyme showed a flexible catalysis over the given ranges of temperature, pH, and divalent cationic conditions for O-methylation.

Mitochondria-Targeted Triphenylphosphonium-Based Compounds: Syntheses, Mechanisms of Action, and Therapeutic and Diagnostic Applications

Mitochondria are recognized as one of the most important targets for new drug design in cancer, cardiovascular, and neurological diseases. Currently, the most effective way to deliver drugs specifically to mitochondria is by covalent linking a lipophilic cation such as an alkyltriphenylphosphonium moiety to a pharmacophore of interest. Other delocalized lipophilic cations, such as rhodamine, natural and synthetic mitochondria-targeting peptides, and nanoparticle vehicles, have also been used for mitochondrial delivery of small molecules. Depending on the approach used, and the cell and mitochondrial membrane potentials, more than 1000-fold higher mitochondrial concentration can be achieved. Mitochondrial targeting has been developed to study mitochondrial physiology and dysfunction and the interaction between mitochondria and other subcellular organelles and for treatment of a variety of diseases such as neurodegeneration and cancer. In this Review, we discuss efforts to target small-molecule compounds to mitochondria for probing mitochondria function, as diagnostic tools and potential therapeutics. We describe the physicochemical basis for mitochondrial accumulation of lipophilic cations, synthetic chemistry strategies to target compounds to mitochondria, mitochondrial probes, and sensors, and examples of mitochondrial targeting of bioactive compounds. Finally, we review published attempts to apply mitochondria-targeted agents for the treatment of cancer and neurodegenerative diseases.

Liraglutide ameliorates cardiotoxicity induced by doxorubicin in rats through the Akt/GSK-3β signaling pathway

Doxorubicin (Dox)-induced cardiotoxicity constitutes the major adverse effect that limited its use. We investigated the possible protective effects of liraglutide on Dox-induced cardiotoxicity in rats. Rats were divided into the following groups: control group rats received normal saline [1 ml/kg, intraperitoneal (i.p.)]; doxorubicin group rats received doxorubicin (1.25 mg/kg, i.p.), four times per week for 4 weeks; and liraglutide group rats received doxorubicin (1.25 mg/kg, i.p.) four times per week for 4 weeks then received liraglutide (100 μg/kg, i.p) daily for 4 weeks. At the end of the study, animals were sacrificed and serum creatine kinase-MB (CK-MB) and troponin I levels were determined. Malondialdehyde (MDA), superoxide dismutase (SOD), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and caspase-3 levels of the heart were determined. Cardiac AMPK, phosphorylated-Akt, tissue growth factor-β1 (TGF-β1), and GSK3-β levels of the heart were determined. Hematoxylin and eosin (H&E) stained sections form the heart were examined as well as immunohistochemical sections for detection of Bcl-2 expression. Dox treatment increased serum level of troponin I and CK-MB while decreased SOD activity, decreased AMPK, and p-Akt cardiac levels with increased in MDA, IL-6, TNF-α,GSK-3b, TGFB1, and caspase-3 levels in the heart with inflammation and necrosis in cardiac histopathology with decreased Bcl-2. Treatment with liraglutide decreased troponin I and CK-MB while increased SOD activity, AMPK, p-Akt with decrements in MDA, IL-6, TNF-α, GSK-3β, TGF-β1, and caspase-3 levels with attenuation of inflammation and necrosis while increased Bcl-2 expression. Liraglutide may thus represent a new clinical tool for the treatment of Dox-induced cardiotoxicity.

Use of liposomal doxorubicin for adjuvant chemotherapy of breast cancer in clinical practice

Breast cancer is one of the malignant tumors with the highest morbidity and mortality. It is helpful to reduce the rate of tumor recurrence and metastasis by treating breast cancer with adjuvant chemotherapy, so as to increase the cure rate or survival of patients. In recent years, liposomes have been regarded as a kind of new carrier for targeted drugs. Being effective for enhancing drug efficacy and reducing side effects, they have been widely used for developing anticancer drugs. As a kind of anthracycline with high anticancer activity, doxorubicin can treat or alleviate a variety of malignant tumors effectively when it is used on its own or in combination with other anticancer drugs. Although liposomal doxorubicin has been extensively used in the adjuvant chemotherapy of breast cancer, its exact therapeutic efficacy and side effects have not been definitely proven. Various clinical studies have adopted different combined regimes, dosages, and staging, so their findings differ to certain extent. This paper reviews the clinical application of liposomal doxorubicin in the adjuvant chemotherapy of breast cancer and illustrates therapeutic effects and side effects of pegylated liposomal doxorubicin (PLD) and non-PLD (NPLD) in clinical research, in order to discuss the strategies for applying these drugs in such adjuvant chemotherapy, looking forward to providing references for related research and clinical treatment in terms of dosage, staging, combined regimes, and analysis methods and so on.

Early transcriptional alteration of histone deacetylases in a murine model of doxorubicin-induced cardiomyopathy

Doxorubicin is a potent chemotherapeutic agent that is widely-used to treat a variety of cancers but causes acute and chronic cardiac injury, severely limiting its use. Clinically, the acute side effects of doxorubicin are mostly manageable, whereas the delayed consequences can lead to life-threatening heart failure, even decades after cancer treatment. The cardiotoxicity of doxorubicin is subject to a critical cumulative dose and so dosage limitation is considered to be the best way to reduce these effects. Hence, a number of studies have defined a "safe dose" of the drug, both in animal models and clinical settings, with the aim of avoiding long-term cardiac effects. Here we show that a dose generally considered as safe in a mouse model can induce harmful changes in the myocardium, as early as 2 weeks after infusion. The adverse changes include the development of fibrotic lesions, disarray of cardiomyocytes and a major transcription dysregulation. Importantly, low-dose doxorubicin caused specific changes in the transcriptional profile of several histone deacetylases (HDACs) which are epigenetic regulators of cardiac remodelling. This suggests that cardioprotective therapies, aimed at modulating HDACs during doxorubicin treatment, deserve further exploration.

The Impact of Melatonin on Colon Cancer Cells' Resistance to Doxorubicin in an in Vitro Study

Multi-drug resistance (MDR) is the main cause of low effectiveness of cancer chemotherapy. P-glycoprotein (P-gp) is one of the main factors determining MDR. Some studies indicate the potential role of melatonin (MLT) in MDR. In this study, we examined the effect of MLT on colon cancer cell’s resistance to doxorubicin (DOX). Using the sulforhodamine B (SRB), method the effect of tested substances on the survival of LoVo (colon cancer cells sensitive to DOX) and LoVo_DX (colon cancer cells resistant to DOX) was rated. Using immunocytochemistry (ICC), the expression of P-gp in the LoVo and LoVo_DX was determined. With the real-time PCR (RT-PCR) technique, the ABCB1 expression in LoVo_DX was evaluated. Based on the results, it was found that MLT in some concentrations intensified the cytotoxicity effect of DOX in the LoVo_DX cells. In the ICC studies, it was demonstrated that certain concentrations of MLT and DOX cause an increase in the percentage of cells expressing P-gp, which correlates positively with ABCB1 expression (RT-PCR). The mechanism of overcoming resistance by MLT is probably not only associated with the expression of P-gp. It seems appropriate to carry out further research on the use of MLT as the substance supporting cancer chemotherapy.

Genetically encoded calcium indicators for studying long-term calcium dynamics during apoptosis

Intracellular calcium release is essential for regulating almost all cellular functions. Specific spatio-temporal patterns of cytosolic calcium elevations are critical determinants of cell fate in response to pro-apoptotic cellular stressors. As the apoptotic program can take hours or days, measurement of long-term calcium dynamics are essential for understanding the mechanistic role of calcium in apoptotic cell death. Due to the technical limitations of using calcium-sensitive dyes to measure cytosolic calcium little is known about long-term calcium dynamics in living cells after treatment with apoptosis-inducing drugs. Genetically encoded calcium indicators could potentially overcome some of the limitations of calcium-sensitive dyes. Here, we compared the performance of the genetically encoded calcium indicators GCaMP6s and GCaMP6f with the ratiometric dye Fura-2. GCaMP6s performed as well or better than Fura-2 in detecting agonist-induced calcium transients. We then examined the utility of GCaMP6s for continuously measuring apoptotic calcium release over the course of ten hours after treatment with staurosporine. We found that GCaMP6s was suitable for measuring apoptotic calcium release over long time courses and revealed significant heterogeneity in calcium release dynamics in individual cells challenged with staurosporine. Our results suggest GCaMP6s is an excellent indicator for monitoring long-term changes cytosolic calcium during apoptosis.

Chemophototherapy: An Emerging Treatment Option for Solid Tumors

Near infrared (NIR) light penetrates human tissues with limited depth, thereby providing a method to safely deliver non-ionizing radiation to well-defined target tissue volumes. Light-based therapies including photodynamic therapy (PDT) and laser-induced thermal therapy have been validated clinically for curative and palliative treatment of solid tumors. However, these monotherapies can suffer from incomplete tumor killing and have not displaced existing ablative modalities. The combination of phototherapy and chemotherapy (chemophototherapy, CPT), when carefully planned, has been shown to be an effective tumor treatment option preclinically and clinically. Chemotherapy can enhance the efficacy of PDT by targeting surviving cancer cells or by inhibiting regrowth of damaged tumor blood vessels. Alternatively, PDT-mediated vascular permeabilization has been shown to enhance the deposition of nanoparticulate drugs into tumors for enhanced accumulation and efficacy. Integrated nanoparticles have been reported that combine photosensitizers and drugs into a single agent. More recently, light-activated nanoparticles have been developed that release their payload in response to light irradiation to achieve improved drug bioavailability with superior efficacy. CPT can potently eradicate tumors with precise spatial control, and further clinical testing is warranted.

The dual-hit metabolic modulator LDCA synergistically potentiates doxorubicin to selectively combat cancer-associated hallmarks

Dual-hit metabolic modulator LDCA synergistically potentiates doxorubicin to counter melanoma progression.

Mitoxantrone and Analogues Bind and Stabilize i-Motif Forming DNA Sequences

There are hundreds of ligands which can interact with G-quadruplex DNA, yet very few which target i-motif. To appreciate an understanding between the dynamics between these structures and how they can be affected by intervention with small molecule ligands, more i-motif binding compounds are required. Herein we describe how the drug mitoxantrone can bind, induce folding of and stabilise i-motif forming DNA sequences, even at physiological pH. Additionally, mitoxantrone was found to bind i-motif forming sequences preferentially over double helical DNA. We also describe the stabilisation properties of analogues of mitoxantrone. This offers a new family of ligands with potential for use in experiments into the structure and function of i-motif forming DNA sequences.

Development of novel self-assembled ES-PLGA hybrid nanoparticles for improving oral absorption of doxorubicin hydrochloride by P-gp inhibition: In vitro and in vivo evaluation

To increase the encapsulation efficiency and oral absorption of doxorubicin hydrochloride (DOX), a novel drug delivery system of enoxaparin sodium-PLGA hybrid nanoparticles (EPNs) was successfully designed. By introducing the negative polymer of enoxaparin sodium (ES) to form an electrostatic complex with the cationic drug, DOX, the encapsulation efficiency (93.78%) of DOX was significantly improved. The X-ray diffraction (XRD) results revealed that the DOX-ES complex was in an amorphous form. An in vitro release (pH6.8 PBS) study showed the excellent sustained-release characteristics of DOX-loaded EPNs (DOX-EPNs). In addition, in situ intestinal perfusion and intestinal biodistribution experiments demonstrated the improved membrane permeability and intestinal wall bioadhesion of DOX-EPNs, and caveolin- and clathrin-mediated endocytosis pathways were the main mechanisms responsible. The cytotoxicity of DOX was significantly increased by EPNs in Caco-2 cells, compared with DOX-Sol. Confocal laser scanning microscope (CLSM) images confirmed that the amount of DOX-EPNs internalized by Caco-2 cells was higher than that of DOX-Sol showing that P-glycoprotein-mediated drug efflux was reduced by the introduction of EPNs. The qualitative detection of transcytosis demonstrated the ability of the nanoparticles (NPs) to cross Caco-2 cell monolayers. An in vivo toxicity experiment demonstrated that DOX-EPNs reduced cardiac and renal toxic effects and were biocompatible. An in vivo pharmacokinetics study showed that the AUC_(0-t) and t_1/2 of DOX-EPNs were increased to 3.63-fold and 2.47-fold in comparison with DOX solution (DOX-Sol), respectively. All these results indicated that the novel EPNs were an excellent platform to improve the encapsulation efficiency of an aqueous solution of this antitumor drug and its oral bioavailability.

Brain-derived neurotrophic factor attenuates doxorubicin-induced cardiac dysfunction through activating Akt signalling in rats

The clinical application of doxorubicin (Dox) is limited by its adverse effect of cardiotoxicity. Previous studies have suggested the cardioprotective effect of brain‐derived neurotrophic factor (BDNF). We hypothesize that BDNF could protect against Dox‐induced cardiotoxicity. Sprague Dawley rats were injected with Dox (2.5 mg/kg, 3 times/week, i.p.), in the presence or absence of recombinant BDNF (0.4 μg/kg, i.v.) for 2 weeks. H9c2 cells were treated with Dox (1 μM) and/or BDNF (400 ng/ml) for 24 hrs. Functional roles of BDNF against Dox‐induced cardiac injury were examined both in vivo and in vitro. Protein level of BDNF was reduced in Dox‐treated rat ventricles, whereas BDNF and its receptor tropomyosin‐related kinase B (TrkB) were markedly up‐regulated after BDNF administration. Brain‐derived neurotrophic factor significantly inhibited Dox‐induced cardiomyocyte apoptosis, oxidative stress and cardiac dysfunction in rats. Meanwhile, BDNF increased cell viability, inhibited apoptosis and DNA damage of Dox‐treated H9c2 cells. Investigations of the underlying mechanisms revealed that BDNF activated Akt and preserved phosphorylation of mammalian target of rapamycin and Bad without affecting p38 mitogen‐activated protein kinase and extracellular regulated protein kinase pathways. Furthermore, the beneficial effect of BDNF was abolished by BDNF scavenger TrkB‐Fc or Akt inhibitor. In conclusion, our findings reveal a potent protective role of BDNF against Dox‐induced cardiotoxicity by activating Akt signalling, which may facilitate the safe use of Dox in cancer treatment.

Valproic Acid as a Promising Co-Treatment With Paclitaxel and Doxorubicin in Different Ovarian Carcinoma Cell Lines

OBJECTIVE

The current preferred treatment of ovarian cancer is combination chemotherapy, usually a platinum-based drug coupled with paclitaxel (PTX). Here, we investigated whether co-treatment with valproic acid (VPA) could increase the efficiency of various ovarian cancer drugs-PTX, doxorubicin (DOX), carboplatin (CBP), and cyclophosphamide (CP)-in different ovarian cancer cell lines.

METHODS

Three different ovarian cancer cell lines (OVCAR-3, TOV-21G, and TOV-112D) were treated with chemotherapeutic drugs, alone or in combination with VPA. Cell viability (XTT assay), caspase-3 activity, and the expression of cell cycle- and apoptosis-related genes and proteins were assessed. Furthermore, the effects of these drugs on α-tubulin acetylation and DNA fragmentation were investigated.

RESULTS

Paclitaxel and DOX decreased cell viability and increased caspase-3 activity, and co-treatment with VPA enhanced this effect. Carboplatin and CP had no effect. Responses to treatment with PAX and DOX together with VPA on gene expression profile were highly variable and depended on the cell line investigated. However, a common feature in all cell lines was an increased expression of CDKN1A, CCNE1, PARP1, and PARP3. Co-treatment with VPA enhanced the effect of DOX and PAX on most protein expressions investigated in TOV-21G and TOV-112D cell lines, whereas in OVCAR-3, the most effect was seen with DOX with VPA. Valproic acid did not increase PTX-induced α-tubulin acetylation. An additive effect of DOX with VPA on DNA fragmentation was observed in TOV-21G and TOV-112D cell lines but not in the OVCAR-3.

CONCLUSIONS

Our results indicate that VPA could be a promising agent in combined anticancer therapy for ovarian cancer, with the combination of VPA and DOX being the most effective. Certainly, additional in vivo and ex vivo experiments are necessary to investigate the molecular mechanisms of action underlying the cellular effects reported here and to study possible clinically relevant effects in ovarian cancer explants.

Utility of Dexrazoxane for the Attenuation of Epirubicin-Induced Genetic Alterations in Mouse Germ Cells

Dexrazoxane has been approved to treat anthracycline-induced cardiomyopathy and extravasation. However, the effect of dexrazoxane on epirubicin-induced genetic alterations in germ cells has not yet been reported. Thus, the aim of this study was to determine whether dexrazoxane modulates epirubicin-induced genetic damage in the germ cells of male mice. Our results show that dexrazoxane was not genotoxic at the tested doses. Furthermore, it protected mouse germ cells against epirubicin-induced genetic alterations as detected by the reduction in disomic and diploid sperm, spermatogonial chromosomal aberrations, and abnormal sperm heads. The attenuating effect of dexrazoxane was greater at higher dose, indicating a dose-dependent effect. Moreover, sperm motility and count were ameliorated by dexrazoxane pretreatment. Epirubicin induced marked biochemical changes characteristic of oxidative DNA damage including elevated 8-hydroxy-2'-deoxyguanosine levels and reduction in reduced glutathione. Pretreatment of mice with dexrazoxane before epirubicin challenge restored these altered endpoints. We conclude that dexrazoxane may efficiently mitigate the epirubicin insult in male germ cells, and prevent the enhanced risk of abnormal reproductive outcomes and associated health risks. Thus, pretreating patients with dexrazoxane prior to epirubicin may efficiently preserve not only sperm quality but also prevent the transmission of genetic damage to future generations.

Modeling and Analysis of Intercalant Effects on Circular DNA Conformation

The large-scale conformation of DNA molecules plays a critical role in many basic elements of cellular functionality and viability. By targeting the structural properties of DNA, many cancer drugs, such as anthracyclines, effectively inhibit tumor growth but can also produce dangerous side effects. To enhance the development of innovative medications, rapid screening of structural changes to DNA can provide important insight into their mechanism of interaction. In this study, we report changes to circular DNA conformation from intercalation with ethidium bromide using all-atom molecular dynamics simulations and characterized experimentally by translocation through a silicon nitride solid-state nanopore. Our measurements reveal three distinct current blockade levels and a 6-fold increase in translocation times for ethidium bromide-treated circular DNA as compared to untreated circular DNA. We attribute these increases to changes in the supercoiled configuration hypothesized to be branched or looped structures formed in the circular DNA molecule. Further evidence of the conformational changes is demonstrated by qualitative atomic force microscopy analysis. These results expand the current methodology for predicting and characterizing DNA tertiary structure and advance nanopore technology as a platform for deciphering structural changes of other important biomolecules.

Population pharmacokinetics of doxorubicin and doxorubicinol in patients diagnosed with non-Hodgkin's lymphoma

AIMS

The aims of the study were: (i) to characterize the pharmacokinetics (PK) of doxorubicin (DOX) and doxorubicinol (DOXol) in patients diagnosed with non-Hodgkin's lymphoma (NHL) using a population approach; (ii) to evaluate the influence of various covariates on the PK of DOX; and (iii) to evaluate the role of DOX and DOXol exposure in haematological toxicity.

METHODS

Population PK modelling (using NONMEM) was performed using DOX and DOXol plasma concentration-time data from 45 NHL patients treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone). The influence of drug exposure on haematological toxicity was analysed using the Mann-Whitney-Wilcoxon test.

RESULTS

A five-compartment model, three for DOX and two for DOXol, with first-order distribution and elimination for both entities best described the data. Population estimates for parent drug (CL) and metabolite (CL_m ) clearance were 62 l h^-1 and 27 l h^-1 , respectively. The fraction metabolized to DOXol (F_m ) was estimated at 0.22. While bilirubin and aspartate aminotransferase showed an influence on the CL and CL_m , the objective function value decrease was not statistically significant. A trend towards an association between the total area under the concentration-time curve (AUC_total ), the area under the concentration-time curve for DOX (AUC) plus the area under the concentration-time curve for DOXol (AUC_m ), and the neutropenia grade (P = 0.068) and the neutrophil counts (P = 0.089) was observed, according to an exponential relationship.

CONCLUSIONS

The PK of DOX and DOXol were well characterized by the model developed, which could be used as a helpful tool to optimize the dosage of this drug. The results suggest that the main active metabolite of DOX, DOXol, is involved in the haematological toxicity of the parent drug.

Histopathologic Features Seen with Radiation Recall or Enhancement Eruptions

Background:

Although a radiation recall or enhancement eruption has been associated with a number of chemotherapeutic drugs, the histologic features have rarely been described.

Objective:

Our goal was to define the histologic features of radiation recall and enhancement eruptions in order to better understand their pathogenesis.

Methods:

We present ten patients on chemotherapeutic agents who developed erythematous maculopapular to psoriasiform eruptions often with associated follicular pustules. These eruptions occurred at the sites of prior or concurrent radiation therapy.

Results:

The most common class of drugs inducing these reactions were antibiotic chemotherapeutic agents alone or in combination with other chemotherapeutic drugs. In addition to routine histology, in four patients immunohistochemical staining for p53 was performed at the sites of the eruptions after resolution and at noninvolved sites matched for ultraviolet radiation (UVR) exposure. Histologic features in patients receiving concurrent radiation therapy included epidermal dysplasia, keratinocytes showing features of necrosis, increased mitotic figures, and a mixed inflammatory infiltrate. At sites of prior radiation therapy, the biopsy specimens showed a similar spectrum of epidermal changes and, in some cases, psoriasiform dermatitis with clearing within cells in the upper layers of the epidermis. Additional dermal changes included dermal fibrosis, vasodilatation, and atypical fibroblasts. Moderate to marked solar elastosis was seen in the majority of biopsy specimens. Immunohistochemical studies after resolution showed only a modest increase in p53 staining in epidermal keratinocytes in 3 of 4 sites of recall and enhancement eruptions after resolution of the reactions compared to skin that was matched for similar UVR exposure.

Conclusion:

Cumulative direct DNA damage and oxidative stress are probably important in radiation recall and enhancement eruptions, and these changes may be modulated by underlying nutritional deficits. Cumulative p53 mutations may play some role but are probably not a major factor in these eruptions. Mitochondrial dysfunction, which is known to occur with prior and concurrent radiation and chemotherapy, may be important in these eruptions. In addition to improvements in general nutrition, topical or oral antioxidant therapy may be a potential therapy to avoid radiation enhancement and recall reactions.

Azoreductases in drug metabolism

Azoreductases are flavoenzymes that have been characterized in a range of prokaryotes and eukaryotes. Bacterial azoreductases are associated with the activation of two classes of drug, azo drugs for the treatment of inflammatory bowel disease and nitrofuran antibiotics. The mechanism of reduction of azo compounds is presented; it requires tautomerisation of the azo compound to a quinoneimine and provides a unifying mechanism for the reduction of azo and quinone substrates by azoreductases. The importance of further work in the characterization of azoreductases from enteric bacteria is highlighted to aid in the development of novel drugs for the treatment of colon related disorders. Human azoreductases are known to play a crucial role in the metabolism of a number of quinone-containing cancer chemotherapeutic drugs. The mechanism of hydride transfer to quinones, which is shared not only between eukaryotic and prokaryotic azoreductases but also the wider family of NAD(P)H quinone oxidoreductases, is outlined. The importance of common single nucleotide polymorphisms (SNPs) in human azoreductases is described not only in cancer prognosis but also with regard to their effects on the efficacy of quinone drug-based cancer chemotherapeutic regimens. This highlights the need to screen patients for azoreductase SNPs ahead of treatment with these regimens.

LINKED ARTICLES

This article is part of a themed section on Drug Metabolism and Antibiotic Resistance in Micro-organisms. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.14/issuetoc.

Increased proapoptotic activity of electron beam irradiated doxorubicin and epirubicin in multidrug-resistant human leukemic cells

This study evaluated the effect of electron beam irradiation on the cytotoxic activity of anthracycline antibiotics such as doxorubicin (DOX), epirubicin (EPI), and dunorubicin (DAU) in human acute lymphoblastic leukemia cell line CCRF-CEM and its multidrug-resistant variant CCRF-VCR1000 cell line characterized by the overexpression of ABCB1 gene. Drugs were irradiated at doses of 10 and 25 kGy. Data from EPR studies proved that the highest concentration of free radicals was found in DOX and that the number of stable free radicals is always greater after irradiation. In in vitro studies, a higher cytotoxic activity of irradiated DOX and EPI in multidrug-resistant CCRF-VCR1000 cells was observed. This tendency was maintained during the storage at 4 °C for 90 days. Changes in CCRF-CEM cells' viability were not dependent on the irradiation status and its dose and were only drug-concentration dependent in all measurement time points. It was proved that increased potency of 25 kGy e-beam irradiated drugs results from their enhanced proapoptotic activity. Apoptotic cell death observed in CCRF-VCR1000 cells treated with irradiated drugs was caspase-8, -9, and -3 dependent and related to the increased Bax/Bcl-2 ratio. No significant differences in the effects of irradiated and non-irradiated drugs on p53 and NFκB transcription factor level and their translocation to the nucleus were noted. Increased activity of the irradiated drugs was not dependent on ABCB1 level.

Rhodomycin A, a novel Src-targeted compound, can suppress lung cancer cell progression via modulating Src-related pathways

Src activation is involved in cancer progression and the interplay with EGFR. Inhibition of Src activity also represses the signalling pathways regulated by EGFR. Therefore, Src has been considered a target molecule for drug development. This study aimed to identify the compounds that target Src to suppress lung cancer tumourigenesis and metastasis and investigate their underlying molecular mechanisms. Using a molecular docking approach and the National Cancer Institute (NCI) compound dataset, eight candidate compounds were selected, and we evaluated their efficacy. Among them, rhodomycin A was the most efficient at reducing the activity and expression of Src in a dose-dependent manner, which was also the case for Src-associated proteins, including EGFR, STAT3, and FAK. Furthermore, rhodomycin A significantly suppressed cancer cell proliferation, migration, invasion, and clonogenicity in vitro and tumour growth in vivo. In addition, rhodomycin A rendered gefitinib-resistant lung adenocarcinoma cells more sensitive to gefitinib treatment, implying a synergistic effect of the combination therapy. Our data also reveal that the inhibitory effect of rhodomycin A on lung cancer progression may act through suppressing the Src-related multiple signalling pathways, including PI3K, JNK, Paxillin, and p130cas. These findings will assist the development of anti-tumour drugs to treat lung cancer.

Dual-Cross-Linked Methacrylated Alginate Sub-Microspheres for Intracellular Chemotherapeutic Delivery

Intracellular delivery vehicles comprised of methacrylated alginate (Alg-MA) were developed for the internalization and release of doxorubicin hydrochloride (DOX). Alg-MA was synthesized via an anhydrous reaction, and a mixture of Alg-MA and DOX was formed into sub-microspheres using a water/oil emulsion. Covalently cross-linked sub-microspheres were formed via exposure to green light, in order to investigate effects of cross-linking on drug release and cell internalization, compared to traditional techniques, such as ultraviolet (UV) light irradiation. Cross-linking was performed using light exposure alone or in combination with ionic cross-linking using calcium chloride (CaCl2). Alg-MA sub-microsphere diameters were between 88 and 617 nm, and ζ-potentials were between -20 and -37 mV. Using human lung epithelial carcinoma cells (A549) as a model, cellular internalization was confirmed using flow cytometry; different sub-microsphere formulations varied the efficiency of internalization, with UV-cross-linked sub-microspheres achieving the highest internalization percentages. While blank (nonloaded) Alg-MA submicrospheres were noncytotoxic to A549 cells, DOX-loaded sub-microspheres significantly reduced mitochondrial activity after 5 days of culture. Photo-cross-linked Alg-MA sub-microspheres may be a potential chemotherapeutic delivery system for cancer treatment.

Lipid-Based Drug Delivery Systems in Cancer Therapy: What Is Available and What Is Yet to Come

Cancer is a leading cause of death in many countries around the world. However, the efficacy of current standard treatments for a variety of cancers is suboptimal. First, most cancer treatments lack specificity, meaning that these treatments affect both cancer cells and their normal counterparts. Second, many anticancer agents are highly toxic, and thus, limit their use in treatment. Third, a number of cytotoxic chemotherapeutics are highly hydrophobic, which limits their utility in cancer therapy. Finally, many chemotherapeutic agents exhibit short half-lives that curtail their efficacy. As a result of these deficiencies, many current treatments lead to side effects, noncompliance, and patient inconvenience due to difficulties in administration. However, the application of nanotechnology has led to the development of effective nanosized drug delivery systems known commonly as nanoparticles. Among these delivery systems, lipid-based nanoparticles, particularly liposomes, have shown to be quite effective at exhibiting the ability to: 1) improve the selectivity of cancer chemotherapeutic agents; 2) lower the cytotoxicity of anticancer drugs to normal tissues, and thus, reduce their toxic side effects; 3) increase the solubility of hydrophobic drugs; and 4) offer a prolonged and controlled release of agents. This review will discuss the current state of lipid-based nanoparticle research, including the development of liposomes for cancer therapy, different strategies for tumor targeting, liposomal formulation of various anticancer drugs that are commercially available, recent progress in liposome technology for the treatment of cancer, and the next generation of lipid-based nanoparticles.

Neurotoxic Effects of Anthracycline- vs Nonanthracycline-Based Chemotherapy on Cognition in Breast Cancer Survivors

IMPORTANCE

Chemotherapy exposure is a known risk factor for cancer-related cognitive impairments. Anthracycline-based regimens are commonly used chemotherapies that have been shown to be associated with cognitive impairment and brain changes in clinical studies.

OBJECTIVE

To directly compare the effects of anthracycline and nonanthracycline regimens on cognitive status and functional brain connectivity.

DESIGN, SETTING, AND PARTICIPANTS

In this observational study, we retrospectively examined cognitive and resting state functional magnetic resonance imaging data acquired from 62 primary breast cancer survivors (mean [SD] age, 54.7 [8.5] years) who were more than 2 years off-therapy, on average. Twenty of these women received anthracycline-based chemotherapy as part of their primary treatment, 19 received nonanthracycline regimens, and 23 did not receive any chemotherapy. Participants were enrolled at a single academic institution (Stanford University) from 2008 to 2014, and the study analyses were performed at this time.

MAIN OUTCOMES AND MEASURES

Cognitive status was measured using standardized neuropsychological tests, and functional brain connectivity was evaluated using resting state functional magnetic resonance imaging with a focus on the brain's default mode network.

RESULTS

The anthracycline group demonstrated significantly lower verbal memory performance including immediate recall (F = 3.73; P = .03) and delayed recall (F = 11.11; P < .001) as well as lower left precuneus connectivity (F = 7.48; P = .001) compared with the other 2 groups. Patient-reported outcomes related to cognitive dysfunction (F = 7.27; P = .002) and psychological distress (F = 5.64; P = .006) were similarly elevated in both chemotherapy groups compared with the non-chemotherapy-treated controls.

CONCLUSIONS AND RELEVANCE

These results suggest that anthracyclines may have greater negative effects than nonanthracycline regimens on particular cognitive domains and brain network connections. Both anthracycline and nonanthracycline regimens may have nonspecific effects on other cognitive domains as well as certain patient reported outcomes. Further research is needed to identify potential methods for protecting the brain against the effects of various chemotherapeutic agents.

Anticancer Drug Delivery: An Update on Clinically Applied Nanotherapeutics

The development of chemotherapy using conventional anticancer drugs has been hindered due to several drawbacks related to their poor water solubility and poor pharmacokinetics, leading to severe adverse side effects and multidrug resistance in patients. Nanocarriers were developed to palliate these problems by improving drug delivery, opening the era of nanomedicine in oncology. Liposomes have been by far the most used nanovectors for drug delivery, with liposomal doxorubicin receiving US FDA approval as early as 1995. Antibody drug conjugates and promising drug delivery systems based on a natural polymer, such as albumin, or a synthetic polymer, are currently undergoing advanced clinical trials or have received approval for clinical applications. However, despite attractive results being obtained in preclinical studies, many well-designed nanodrugs fell short of expectations when tested in patients, evidencing the gap between nanoparticle design and their clinical translation. The aim of this review is to evaluate the extent of nanotherapeutics used in oncology by providing an insight into the most successful concepts. The reasons that prevent nanodrugs from expanding to clinic are discussed, and the efforts that must be taken to take full advantage of the great potential of nanomedicine are highlighted.

Characterization of Cell-Type-Specific Drug Transport and Resistance of Breast Cancers Using Tumor-Microenvironment-on-Chip

Heterogeneous response and resistance of cancer cells to chemotherapeutic drugs pose a significant challenge for successful cancer treatments. In this study, an integrated experimental and theoretical analysis of cellular drug transport was developed. The experimental platform, called tumor-microenvironment-on-chip (T-MOC), is a microfluidic platform where cancer cells were cultured within a three-dimensional extracellular matrix perfused with interstitial fluid. Three types of human breast cancer cell lines (MCF-7, MDA-MB-231, and SUM-159PT) were cultured on this T-MOC platform, and their drug response and resistance to doxorubicin were characterized by time-lapse quantitative fluorescence microscopy. To study the effects of nanoparticle-mediated drug delivery, the transport and action of doxorubicin encapsulated nanoparticles were also examined. Based on the experimental data obtained, a theoretical model was developed to quantify and ultimately predict the cellular transport processes of drugs cell-type specifically. The results demonstrate that the cellular drug transport can be cell-type-specifically quantified by rate constants representing the uptake and efflux of doxorubicin across the cellular membrane.

Green Tea Catechin-Based Complex Micelles Combined with Doxorubicin to Overcome Cardiotoxicity and Multidrug Resistance

Chemotherapy for cancer treatment has been demonstrated to cause some side effects on healthy tissues and multidrug resistance of the tumor cells, which greatly limits therapeutic efficacy. To address these limitations and achieve better therapeutic efficacy, combination therapy based on nanoparticle platforms provides a promising approach through delivering different agents simultaneously to the same destination with synergistic effect. In this study, a novel green tea catechin-based polyion complex (PIC) micelle loaded with doxorubicin (DOX) and (-)-Epigallocatechin-3-O-gallate (EGCG) was constructed through electrostatic interaction and phenylboronic acid-catechol interaction between poly(ethylene glycol)-block-poly(lysine-co-lysine-phenylboronic acid) (PEG-PLys/PBA) and EGCG. DOX was co-loaded in the PIC micelles through π-π stacking interaction with EGCG. The phenylboronic acid-catechol interaction endowed the PIC micelles with high stability under physiological condition. Moreover, acid cleavability of phenylboronic acid-catechol interaction in the micelle core has significant benefits for delivering EGCG and DOX to same destination with synergistic effects. In addition, benefiting from the oxygen free radicals scavenging activity of EGCG, combination therapy with EGCG and DOX in the micelle core could protect the cardiomyocytes from DOX-mediated cardiotoxicity according to the histopathologic analysis of hearts. Attributed to modulation of EGCG on P-glycoprotein (P-gp) activity, this kind of PIC micelles could effectively reverse multidrug resistance of cancer cells. These results suggested that EGCG based PIC micelles could effectively overcome DOX induced cardiotoxicity and multidrug resistance.

A combined ligand- and structure-based approach for the identification of rilmenidine-derived compounds which synergize the antitumor effects of doxorubicin

The clonidine-like central antihypertensive agent rilmenidine, which has high affinity for I1-type imidazoline receptors (I1-IR) was recently found to have cytotoxic effects on cultured cancer cell lines. However, due to its pharmacological effects resulting also from α2-adrenoceptor activation, rilmenidine cannot be considered a suitable anticancer drug candidate. Here, we report the identification of novel rilmenidine-derived compounds with anticancer potential and devoid of α2-adrenoceptor effects by means of ligand- and structure-based drug design approaches. Starting from a large virtual library, eleven compounds were selected, synthesized and submitted to biological evaluation. The most active compound 5 exhibited a cytotoxic profile similar to that of rilmenidine, but without appreciable affinity to α2-adrenoceptors. In addition, compound 5 significantly enhanced the apoptotic response to doxorubicin, and may thus represent an important tool for the development of better adjuvant chemotherapeutic strategies for doxorubicin-insensitive cancers.

Glucosamine-anchored doxorubicin-loaded targeted nano-niosomes: pharmacokinetic, toxicity and pharmacodynamic evaluation

BACKGROUND

Efficacy of anticancer drug is limited due to non-selectivity and toxicities allied with the drug; therefore the heart of the present work is to formulate drug delivery systems targeted selectively towards cancer cells with minimal toxicity to normal cells.

PURPOSE

Targeted drug delivery system of doxorubicin (DOX)-loaded niosomes using synthesized N-lauryl glucosamine (NLG) as a targeting ligand.

METHODS

NLG-anchored DOX niosomes were developed using ethanol injection method.

RESULTS

Developed niosomes had particle size <150 nm and high entrapment efficiency ∼90%. In vivo pharmacokinetics exhibited long circulating nature of targeted niosomes with improved bioavailability, which significantly reduced CL and Vd than DOX solution and non-targeted niosomes (35 fold and 2.5 fold, respectively). Tissue-distribution study and enzymatic assays revealed higher concentration of DOX solution in heart while no toxicity to major organs with developed targeted niosomes was observed. Solid skin melanoma tumor model in mice manifested the commendable targeting potential of targeted niosomes with significant reduction in tumor volume and high % survival rate without drop in body weight in comparison with DOX solution and non-targeted niosomes of DOX.

CONCLUSION

The glucosamine-anchored DOX-loaded targeted niosomes showed its potential in cancer targeted drug therapy with reduced toxicity. Abbreviations ALT alanine transaminase CL clearance CPK creatinine phosphokinase DOX doxorubicin EDC.HCL ethyl carbidimide hydrochloride GLUT glucose transporter GSH glutathione S-transferase LDH lactate dehydrogenase LHRH luteinizing hormone-releasing hormone MDA malonaldehyde NHS N-hydroxy succinimide NLG N-lauryl glucosamine NTAR DoxNio non-targeted doxorubicin niosomes PBS phosphate buffer saline RGD argynyl glycyl aspartic acid SGOT serum glutamate oxaloacetate transaminase SGPT serum glutamate pyruvate transaminase SOD superoxide dismutase TAR DoxNio targeted doxorubicin niosomes Vd volume of distribution.

Concepts in cardio-oncology: definitions, mechanisms, diagnosis and treatment strategies of cancer therapy-induced cardiotoxicity

There has been considerable improvement in cancer survival rates, primarily through improved preventive strategies and novel anticancer drugs. Cancer is now becoming a chronic illness and as such both short and long-term cardiotoxic effects of cancer therapy are becoming more apparent. This has led to the emergence of a new multidisciplinary specialty known as cardio-oncology, with the purpose of identifying patients who are at a higher risk for developing cardiotoxicity so that appropriate surveillance, treatment and follow-up strategies may be instituted early. The mechanisms of cardiotoxicity caused by commonly used anticancer agents are reviewed, along with the latest advances in diagnostic and preventative strategies, with the overall objective of allowing cancer patients to continue both lifesaving and palliative treatments for their malignancy.

Inhibition of human anthracycline reductases by emodin - A possible remedy for anthracycline resistance

The clinical application of anthracyclines, like daunorubicin and doxorubicin, is limited by two factors: dose-related cardiotoxicity and drug resistance. Both have been linked to reductive metabolism of the parent drug to their metabolites daunorubicinol and doxorubicinol, respectively. These metabolites show significantly less anti-neoplastic properties as their parent drugs and accumulate in cardiac tissue leading to chronic cardiotoxicity. Therefore, we aimed to identify novel and potent natural inhibitors for anthracycline reductases, which enhance the anticancer effect of anthracyclines by preventing the development of anthracycline resistance. Human enzymes responsible for the reductive metabolism of daunorubicin were tested for their sensitivity towards anthrachinones, in particular emodin and anthraflavic acid. Intense inhibition kinetic data for the most effective daunorubicin reductases, including IC50- and Ki-values, the mode of inhibition, as well as molecular docking, were compiled. Subsequently, a cytotoxicity profile and the ability of emodin to reverse daunorubicin resistance were determined using multiresistant A549 lung cancer and HepG2 liver cancer cells. Emodin potently inhibited the four main human daunorubicin reductases in vitro. Further, we could demonstrate that emodin is able to synergistically sensitize human cancer cells towards daunorubicin at clinically relevant concentrations. Therefore, emodin may yield the potential to enhance the therapeutic effectiveness of anthracyclines by preventing anthracycline resistance via inhibition of the anthracycline reductases. In symphony with its known pharmacological properties, emodin might be a compound of particular interest in the management of anthracycline chemotherapy efficacy and their adverse effects.

Cellular processing and destinies of artificial DNA nanostructures

This review gives a panoramic view of the many DNA nanotechnology applications in cells, mechanistic understanding of how and where their interactions occur and their subsequent outcomes.

Reversible and formaldehyde-mediated covalent binding of a bis-amino mitoxantrone analogue to DNA

The ability of the anthracenedione anticancer drug WEHI-150 to form covalent adducts with DNA, after activation by formaldehyde, has been studied by mass spectrometry, HPLC and NMR spectroscopy.

Impact of dexrazoxane on doxorubicin-induced aneuploidy in somatic and germinal cells of male mice

PURPOSE

Despite dexrazoxane's increasing use in mitigating doxorubicin-induced cardiotoxicity, no data are available in the literature on the potential aneugenicity of drug combination. Therefore, detailed evaluation of aneugenic potential of this combination is essential to provide more insights into aneuploidy induction that may play a role in the development of secondary malignancies and reproductive toxicity after treatment with doxorubicin. Thus, our aim was to determine whether dexrazoxane has influence on the aneuploidy induced by doxorubicin in germinal and somatic cells of male mice.

METHODS

Sperm BrdU-incorporation assay, sperm FISH assay and the bone marrow micronucleus test complemented by FISH assay were used to determine aneuoploidy. Moreover, the formation of 8-OHdG, one of the oxidative DNA damage by-products, has been evaluated.

RESULTS

Dexrazoxane was not aneugenic at the doses tested. Pre-treatment of mice with dexrazoxane significantly reduced doxorubicin-induced aneuploidy in a dose-dependent manner. Doxorubicin induced marked biochemical alterations characteristic of oxidative DNA damage, and prior administration of dexrazoxane before doxorubicin challenge ameliorated this biochemical marker.

CONCLUSION

This study provides evidence that dexrazoxane has a protective role in the abatement of doxorubicin-induced aneuploidy. This activity resides, at least in part, in its radical scavenger activity. Thus, dexrazoxane can avert secondary malignancies and abnormal reproductive outcomes in cured cancer patients exposed to doxorubicin.

Drug-induced mitochondrial dysfunction and cardiotoxicity

Mitochondria has an essential role in myocardial tissue homeostasis; thus deterioration in mitochondrial function eventually leads to cardiomyocyte and endothelial cell death and consequent cardiovascular dysfunction. Several chemical compounds and drugs have been known to directly or indirectly modulate cardiac mitochondrial function, which can account both for the toxicological and pharmacological properties of these substances. In many cases, toxicity problems appear only in the presence of additional cardiovascular disease conditions or develop months/years following the exposure, making the diagnosis difficult. Cardiotoxic agents affecting mitochondria include several widely used anticancer drugs [anthracyclines (Doxorubicin/Adriamycin), cisplatin, trastuzumab (Herceptin), arsenic trioxide (Trisenox), mitoxantrone (Novantrone), imatinib (Gleevec), bevacizumab (Avastin), sunitinib (Sutent), and sorafenib (Nevaxar)], antiviral compound azidothymidine (AZT, Zidovudine) and several oral antidiabetics [e.g., rosiglitazone (Avandia)]. Illicit drugs such as alcohol, cocaine, methamphetamine, ecstasy, and synthetic cannabinoids (spice, K2) may also induce mitochondria-related cardiotoxicity. Mitochondrial toxicity develops due to various mechanisms involving interference with the mitochondrial respiratory chain (e.g., uncoupling) or inhibition of the important mitochondrial enzymes (oxidative phosphorylation, Szent-Györgyi-Krebs cycle, mitochondrial DNA replication, ADP/ATP translocator). The final phase of mitochondrial dysfunction induces loss of mitochondrial membrane potential and an increase in mitochondrial oxidative/nitrative stress, eventually culminating into cell death. This review aims to discuss the mechanisms of mitochondrion-mediated cardiotoxicity of commonly used drugs and some potential cardioprotective strategies to prevent these toxicities.

Polylactide-based Magnetic Spheres as Efficient Carriers for Anticancer Drug Delivery

To improve traditional cancer therapies, we synthesized polylactide (PLA) spheres coencapsulating magnetic nanoparticles (MNPs, Fe3O4) and an anticancer drug (doxorubicin, DOX). The synthesis process involves the preparation of Fe3O4 NPs by a coprecipitation method and then PLA/DOX/Fe3O4 spheres using the solvent evaporation (oil-in-water) technique. The Fe3O4 NPs were coated with oleic acid to improve their hydrophobicity and biocompatibility for medical applications. The structure, morphology and properties of the MNPs and PLA/DOX/Fe3O4 spheres were studied using various techniques, such as FTIR, SEM, TEM, TGA, VSM, UV-vis spectroscopy, and zeta potential measurements. The in vitro DOX release from the spheres was prolonged, sustained, and pH-dependent and fit a zero-order kinetics model and an anomalous mechanism. Interestingly, the spheres did not show a DOX burst effect, ensuring the minimal exposure of the healthy cells and an increased drug payload at the tumor site. The pronounced biocompatibility of the PLA/DOX/Fe3O4 spheres with HeLa cells was proven by a WST assay. In summary, the synthesized PLA/DOX/Fe3O4 spheres have the potential for magnetic targeting of tumor cells to transform conventional methods.

Extracorporeal Elimination of Circulating Pegylated Liposomal Doxorubicin (PLD) to Enhance the Benefit of Cytostatic Therapy in Platinum-Resistant Ovarian Cancer Patients

Ovarian cancer is the fifth most common malignancy in the world's female population and with the highest lethality index among gynecological tumors. The prognosis of metastatic disease is usually poor, especially in platinum-resistant cases. There are several options for the treatment of metastatic disease resistant to platinum derivates (e.g. paclitaxel, topotecan and pegylated liposomal doxorubicin), all of which are considered equipotent. Pegylated liposomal doxorubicin (PLD) is a liposomal form of the anthracycline antibiotic doxorubicin. It is characterized by more convenient pharmacokinetics and a different toxicity profile. Cardiotoxicity, the major adverse effect of conventional doxorubicin, is reduced in PLD as well as hematotoxicity, alopecia, nausea and vomiting. Skin toxicity and mucositis, however, emerge as serious issues since they represent dose and schedule-limiting toxicities. The pharmacokinetics of PLD (prolonged biological half-life and preferential distribution into tumor tissue) provide new possibilities to address these toxicity issues. The extracorporeal elimination of circulating liposomes after PLD saturation in the tumor tissue represents a novel and potent strategy to diminish drug toxicity. This article intends to review PLD characteristics and the importance of extracorporeal elimination to enhance treatment tolerance and benefits.