Bleomycin treatment of brain tumors: an evaluation

Advancing cancer therapy: Mechanisms, efficacy, and limitations of calcium electroporation

Calcium electroporation, an innovative technique, uses high-voltage pulses to introduce calcium ions into cells, leading to cell death and tumor growth inhibition. This review explores the potential of calcium electroporation as a promising therapeutic approach in cancer treatment. We provide an in-depth analysis of the underlying mechanisms by which calcium ions function within cells and how their introduction through electroporation can effectively induce cell death in cancer cells. Furthermore, we present a comprehensive overview of the current literature, covering both preclinical and clinical studies, to highlight the safety and efficacy of calcium electroporation in various cancer types, including melanoma, head and neck cancer, and breast cancer. We also discuss the distinct advantages of calcium electroporation over traditional cancer therapies, such as its specific targeting of cancer cells while sparing healthy cells. However, we also address the challenges and limitations associated with this technique, underscoring the need for further research. By providing a comprehensive examination of calcium electroporation, this review aims to contribute to understanding this emerging field and encourage further investigation into its potential as a novel cancer treatment strategy.

A bleomycin-mimicking manganese-porphyrin-conjugated mitochondria-targeting peptoid for cancer therapy

Bleomycin (BLM) is a natural product with established anticancer activity, attributed to its ability to cleave intracellular DNA. BLM complexes with iron (BLM-Fe3+) exhibit peroxidase-like activity, generate reactive oxygen species (ROS), and cause DNA cleavage. Inspired by the mechanism of BLM, we synthesized a novel conjugate of manganese tetraphenylporphyrin (MnTPP) with a biomimetic peptoid (i.e., oligo-N-substituted glycines); this conjugate harnesses the oxidative capabilities of manganese porphyrins combined with the cell-penetrating ability of a previously reported mitochondria-targeting peptoid (MTP). UV-vis spectroscopy showed the formation of Mn(V)-oxo porphyrin, a potent oxidative species, in the presence of hydrogen peroxide, simulating metallobleomycin reactivity. Biological assays demonstrated that MnTPP-MTP significantly boosted ROS production and induced cytotoxicity toward cancer cells, while sparing normal fibroblasts. Tetramethylrhodamine ethyl ester (TMRE) assay revealed reversible, dose-dependent impairment of the mitochondrial membrane potential by MnTPP-MTP treatment. DNA cleavage assays showed that MnTPP-MTP, specifically in the presence of hydrogen peroxide, could elicit substantial DNA damage, in a similar way to BLM. In vivo studies using liposome-encapsulated MnTPP-MTP (lipo-peptoid) indicated superior tumor suppression, without systemic toxicity, when administered locally. Immunofluorescence staining for Ki67 and TUNEL confirmed reduced cell proliferation and increased apoptosis, respectively, validating the anticancer efficacy of lipo-peptoid. These results suggest that MnTPP-MTP, particularly in a liposomal formulation, is a promising new chemotherapeutic agent with robust oxidative mechanisms, poised for further development and application against diverse cancers.

Approach to the Patient: New Era Emerges for Craniopharyngioma Management

Papillary craniopharyngioma (PCP) and adamantinomatous craniopharyngioma (ACP) are distinct, slow-growing tumors of the suprasellar region. Their location, composition, and biology have historically evaded successful surgical radiation and medical therapy. Meanwhile compromise of critical structures either by tumor or treatments increase morbidity, impacting patient and carer quality of life. There has been a paradigm shift in the management of PCP, stemming from the discovery of BRAFV600E mutation in its tumorigenesis. Such a treatment breakthrough may soon be the case for ACP, changing the landscape of craniopharyngioma management. We use a case of ACP partially responding to ERK inhibitor therapy to demonstrate chronicity of disease progression and discuss modern management strategies highlighting the importance of access to tumor agnostic clinical trials, and future directions.

ROS-mediated lysosomal membrane permeabilization and autophagy inhibition regulate bleomycin-induced cellular senescence

Bleomycin exhibits effective chemotherapeutic activity against multiple types of tumors, and also induces various side effects, such as pulmonary fibrosis and neuronal defects, which limit the clinical application of this drug. Macroautophagy/autophagy has been recently reported to be involved in the functions of bleomycin, and yet the mechanisms of their crosstalk remain insufficiently understood. Here, we demonstrated that reactive oxygen species (ROS) produced during bleomycin activation hampered autophagy flux by inducing lysosomal membrane permeabilization (LMP) and obstructing lysosomal degradation. Exhaustion of ROS with N-acetylcysteine relieved LMP and autophagy defects. Notably, we observed that LMP and autophagy blockage preceded the emergence of cellular senescence during bleomycin treatment. In addition, promoting or inhibiting autophagy-lysosome degradation alleviated or exacerbated the phenotypes of senescence, respectively. This suggests the alternation of autophagy activity is more a regulatory mechanism than a consequence of bleomycin-induced cellular senescence. Taken together, we reveal a specific role of bleomycin-induced ROS in mediating defects of autophagic degradation and further regulating cellular senescence in vitro and in vivo. Our findings, conversely, indicate the autophagy-lysosome degradation pathway as a target for modulating the functions of bleomycin. These provide a new perspective for optimizing bleomycin as a clinically applicable chemotherapeutics devoid of severe side-effects.Abbreviations: AT2 cells: type II alveolar epithelial cells; ATG7: autophagy related 7; bEnd.3: mouse brain microvascular endothelial cells; BNIP3L: BCL2/adenovirus E1B interacting protein 3-like; CCL2: C-C motif chemokine ligand 2; CDKN1A: cyclin dependent kinase inhibitor 1A; CDKN2A: cyclin dependent kinase inhibitor 2A; FTH1: ferritin heavy polypeptide 1; γ-H2AX: phosphorylated H2A.X variant histone; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; HUVEC: human umbilical vein endothelial cells; HT22: hippocampal neuronal cell lines; Il: interleukin; LAMP: lysosomal-associated membrane protein; LMP: lysosome membrane permeabilization; MTORC1: mechanistic target of rapamycin kinase complex 1; NAC: N-acetylcysteine; NCOA4: nuclear receptor coactivator 4; PI3K: phosphoinositide 3-kinase; ROS: reactive oxygen species; RPS6KB/S6K: ribosomal protein S6 kinase; SA-GLB1/β-gal: senescence-associated galactosidase, beta 1; SAHF: senescence-associated heterochromatic foci; SASP: senescence-associated secretory phenotype; SEC62: SEC62 homolog, preprotein translocation; SEP: superecliptic pHluorin; SQSTM1/p62: sequestosome 1; TFEB: transcription factor EB.

The Enhancement of Tumor Ablation Effect by the Combination of High-Frequency and Low-Voltage Bipolar Electroporation Pulses

The H-FIRE (high-frequency irreversible electroporation) protocol employs high-frequency bipolar pulses (HFBPs) with a width of ∼1 µs for tumor ablation with slight muscle contraction. However, H-FIRE pulses need a higher electric field to generate a sufficient ablation effect, which may cause undesirable thermal damage.

OBJECTIVE

Recently, combining short high-voltage IRE monopolar pulses with long low-voltage IRE monopolar pulses was shown to enlarge the ablation region. This finding indicates that combining HFBPs with low-voltage bipolar pulses (LVBPs), which are called composited bipolar pulses (CBPs), may enhance the ablation effect.

METHODS

This study designed a pulse generator by modifying a full-bridge inverter. The cell suspension and 3D tumor mimic experiments (U251 cells) were performed to examine the enhancement of the ablation effect.

RESULTS

The generator outputs HFBPs with 0-±2.5 kV and LVBPs with 0-±0.3 kV in one period. The pulse parameters are adjustable by programming on a human-computer interface. The cell suspension experiments showed that CBPs could enhance cytotoxicity, as compared to HFBPs with no cell-killing effect. Even at lower electric energy, the cell viability by CBPs was significantly lower than that of the HFBPs protocol. The ablation experiments on the 3D tumor mimic showed that the CBPs could create a larger connected ablation area. In contrast, the HFBPs protocol with a similar dose generated a nonconnected ablation area.

CONCLUSION

Results indicate that the CBPs protocol can enhance the ablation effect of HFBPs protocol.

SIGNIFICANCE

This proposed generator that uses the CBPs principle may be a useful tool for tumor ablation.

Beyond the Warburg Effect: Oxidative and Glycolytic Phenotypes Coexist within the Metabolic Heterogeneity of Glioblastoma

Glioblastoma (GBM) is the most aggressive primary brain tumor, with a median survival at diagnosis of 16-20 months. Metabolism represents a new attractive therapeutic target; however, due to high intratumoral heterogeneity, the application of metabolic drugs in GBM is challenging. We characterized the basal bioenergetic metabolism and antiproliferative potential of metformin (MF), dichloroacetate (DCA), sodium oxamate (SOD) and diazo-5-oxo-L-norleucine (DON) in three distinct glioma stem cells (GSCs) (GBM18, GBM27, GBM38), as well as U87MG. GBM27, a highly oxidative cell line, was the most resistant to all treatments, except DON. GBM18 and GBM38, Warburg-like GSCs, were sensitive to MF and DCA, respectively. Resistance to DON was not correlated with basal metabolic phenotypes. In combinatory experiments, radiomimetic bleomycin exhibited therapeutically relevant synergistic effects with MF, DCA and DON in GBM27 and DON in all other cell lines. MF and DCA shifted the metabolism of treated cells towards glycolysis or oxidation, respectively. DON consistently decreased total ATP production. Our study highlights the need for a better characterization of GBM from a metabolic perspective. Metabolic therapy should focus on both glycolytic and oxidative subpopulations of GSCs.

Genetic and epigenetic modifications induced by chemotherapeutic drugs: human amniotic fluid stem cells as an in-vitro model

BACKGROUND

Bleomycin, etoposide and cisplatin (BEP) are three chemotherapeutic agents widely used individually or in combination with each other or other chemotherapeutic agents in the treatment of various cancers. These chemotherapeutic agents are cytotoxic; hence, along with killing cancerous cells, they also damage stem cell pools in the body, which causes various negative effects on patients. The epigenetic changes due to the individual action of BEP on stem cells are largely unknown.

METHODS

Human amniotic fluid stem cells (hAFSCs) were treated with our in-vitro standardized dosages of BEP individually, for seven days. The cells were harvested after the treatment and extraction of DNA and RNA were performed. Real-time PCR and flow cytometry were conducted for cell markers analysis. The global DNA methylation was quantified using 5mC specific kit and promoter and CpG methylation % through bisulfite conversion and pyrosequencing. Micro- RNAs (miRNAs) were quantified with real-time qPCR.

RESULTS

The cytotoxic nature of BEP was observed even at low dosages throughout the experiment. We also investigated the change in the expression of various pluripotent and germline markers and found a significant change in the properties of the cells after the treatments. The methylation of DNA at global, promoter and individual CpG levels largely get fluctuated due to the BEP treatment. Several tested miRNAs showed differential expression. No positive correlation between mRNA and protein expression was observed for some markers.

CONCLUSION

Cytotoxic chemotherapeutic agents such as BEP were found to alter stem cell properties of hAFSCs. Different methylation profiles change dynamically, which may explain such changes in cellular properties. Data also suggests that the fate of hAFSCs after treatment may depend upon the interplay between the miRNAs. Finally, our results demonstrate that hAFSCs might prove to be a suitable in-vitro model of stem cells to predict genetic and epigenetic modification due to the action of various drugs.

A 2-D Cell Layer Study on Synergistic Combinations of High-Voltage and Low-Voltage Irreversible Electroporation Pulses

Irreversible electroporation (IRE) employs brief, high-electric field pulses to ablate tumors while preserving the extracellular matrix. Recently, we showed that combining short high-voltage (SHV) IRE pulses and long low-voltage (LLV) IRE pulses can enlarge the tissue ablation region, presumably through a synergistic effect.

OBJECTIVE

The goal of this study is to further investigate the effect of this combination on a 2-D cell layer tumor model.

METHODS

2-D layers of tumor cells are exposed to various SHV and LLV combinations, and the results of propidium iodide (PI) and fluorescein diacetate staining are examined to correlate treatment protocols with the ensuing irreversible and reversible electroporation areas.

RESULTS

The combination of SHV+LLV pulses produces a larger area of electroporation and ablation than LLV+SHV pulses, LLV pulses alone, and SHV pulses alone.

CONCLUSION

Judiciously combining SHV and LLV pulses can produce a synergistic effect that enlarges the electroporation-induced ablation area. A hypothetical explanation for this effect is that it involves a combination of pore expansion and electrolysis induced by LLV pulses in the area that had been reversibly permeabilized by the SHV pulses.

SIGNIFICANCE

This paper is valuable for the design of improved IRE protocols and provides a hypothesis for the mechanisms involved.

Electrochemotherapy - Emerging applications technical advances, new indications, combined approaches, and multi-institutional collaboration

The treatment of tumors with electrochemotherapy (ECT) has surged over the past decade. Thanks to the transient cell membrane permeabilization induced by the short electric pulses used by ECT, cancer cells are exposed to otherwise poorly permeant chemotherapy agents, with consequent increased cytotoxicity. The codification of the procedure in 2006 led to a broad diffusion of the procedure, mainly in Europe, and since then, the progressive clinical experience, together with the emerging technologies, have extended the range of its application. Herein, we review the key advances in the ECT field since the European Standard Operating Procedures on ECT (ESOPE) 2006 guidelines and discuss the emerging clinical data on the new ECT indications. First, technical developments have improved ECT equipment, with custom electrode probes and dedicated tools supporting individual treatment planning in anatomically challenging tumors. Second, the feasibility and short-term efficacy of ECT has been established in deep-seated tumors, including bone metastases, liver malignancies, and pancreatic and prostate cancers (long-needle variable electrode geometry ECT), and gastrointestinal tumors (endoscopic ECT). Moreover, pioneering studies indicate lung and brain tumors as suitable future targets. A further advance relates to new combination strategies with immunotherapy, gene electro transfer (GET), calcium EP, and radiotherapy. Finally and fourth, cross-institutional collaborative groups have been established to refine procedural guidelines, promote clinical research, and explore new indications.

Target-initiated synthesis of fluorescent copper nanoparticles for the sensitive and label-free detection of bleomycin

Fluorescent copper nanoparticles (CuNPs) have received great attention due to their distinct characteristics of facile synthesis, tunable fluorescence emission, high photostability, and biological compatibility, and they have been widely used for chemical and biological analyses. Bleomycins (BLMs) are widely used antitumor agents for the clinical treatment of various cancers. Here, we develop a sensitive and label-free fluorescence method for the quantitative detection of BLM on the basis of BLM-initiated enzymatic polymerization-mediated synthesis of fluorescent CuNPs. We design two hairpin DNAs: one (Hp1) for the recognition of BLM and the other (Hp2) for signal amplification. In the presence of BLM, it may recognize and cleave the 5'-GC-3' site of the Hp1 stem, releasing the 8-17 DNAzyme fragment. The resultant 8-17 DNAzyme fragments may bind with the loop of Hp2 to form a partial double-stranded DNA (dsDNA) duplex, initiating the cyclic cleavage of Hp2 in the presence of Zn2+-dependent DNAzymes and generating numerous new DNA fragments with the free 3'-OH terminal, which can induce the formation of a poly(thymine) (poly-T) sequence with the assistance of terminal deoxynucleotidyl transferase (TdTase). Subsequently, the ploy-T sequence may function as the template for the synthesis of CuNPs with strong fluorescence emission. This method shows good selectivity and high sensitivity with a detection limit as low as 8.1 × 10-16 M, and it exhibits good performance in serum samples. Moreover, this method has distinct advantages of simplicity and low cost, holding great potential in clinical diagnosis and biomedical research.

The Feasibility of Enhancing Susceptibility of Glioblastoma Cells to IRE Using a Calcium Adjuvant

Irreversible electroporation (IRE) is a cellular ablation method used to treat a variety of cancers. IRE works by exposing tissues to pulsed electric fields which cause cell membrane disruption. Cells exposed to lower energies become temporarily permeable while greater energy exposure results in cell death. For IRE to be used safely in the brain, methods are needed to extend the area of ablation without increasing applied voltage, and thus, thermal damage. We present evidence that IRE used with adjuvant calcium (5 mM CaCl₂) results in a nearly twofold increase in ablation area in vitro compared to IRE alone. Adjuvant 5 mM CaCl₂ induces death in cells reversibly electroporated by IRE, thereby lowering the electric field thresholds required for cell death to nearly half that of IRE alone. The calcium-induced death response of reversibly electroporated cells is confirmed by electrochemotherapy pulses which also induced cell death with calcium but not without. These findings, combined with our numerical modeling, suggest the ability to ablate up to 3.2× larger volumes of tissue in vivo when combining IRE and calcium. The ability to ablate a larger volume with lowered energies would improve the efficacy and safety of IRE therapy.

Electrosensitization Increases Antitumor Effectiveness of Nanosecond Pulsed Electric Fields In Vivo

Nanosecond pulsed electric fields are emerging as a new modality for tissue and tumor ablation. We previously reported that cells exposed to pulsed electric fields develop hypersensitivity to subsequent pulsed electric field applications. This phenomenon, named electrosensitization, is evoked by splitting the pulsed electric field treatment in fractions (split-dose treatments) and causes in vitro a 2- to 3-fold increase in cytotoxicity. The aim of this study was to show the benefit of split-dose treatments for in vivo tumor ablation by nanosecond pulsed electric field. KLN 205 squamous carcinoma cells were embedded in an agarose gel or grown subcutaneously as tumors in mice. Nanosecond pulsed electric field ablations were produced using a 2-needle probe with a 6.5-mm interelectrode distance. In agarose gel, splitting a pulsed electric field dose of 300, 300-ns pulses (20 Hz, 4.4-6.4 kV) in 2 equal fractions increased cell death up to 3-fold compared to single-train treatments. We then compared the antitumor effectiveness of these treatments in vivo. At 24 hours after treatment, sensitizing tumors by a split-dose pulsed electric field exposure (150 + 150, 300-ns pulses, 20 Hz, 6.4 kV) caused a 4- and 2-fold tumor volume reduction as compared to sham and single-train treatments, respectively. Tumor volume reduction that exceeds 75% was 43% for split-dose–treated animals compared to only 12% for single-dose treatments. The difference between the 2 experimental groups remained statistically significant for at least 1 week after the treatment. The results show that electrosensitization occurs in vivo and can be exploited to assist in vivo cancer ablation.

Electrosensitization assists cell ablation by nanosecond pulsed electric field in 3D cultures

Previous studies reported a delayed increase of sensitivity to electroporation (termed “electrosensitization”) in mammalian cells that had been subjected to electroporation. Electrosensitization facilitated membrane permeabilization and reduced survival in cell suspensions when the electric pulse treatments were split in fractions. The present study was aimed to visualize the effect of sensitization and establish its utility for cell ablation. We used KLN 205 squamous carcinoma cells embedded in an agarose gel and cell spheroids in Matrigel. A local ablation was created by a train of 200 to 600 of 300-ns pulses (50 Hz, 300–600 V) delivered by a two-needle probe with 1-mm inter-electrode distance. In order to facilitate ablation by engaging electrosensitization, the train was split in two identical fractions applied with a 2- to 480-s interval. At 400–600 V (2.9–4.3 kV/cm), the split-dose treatments increased the ablation volume and cell death up to 2–3-fold compared to single-train treatments. Under the conditions tested, the maximum enhancement of ablation was achieved when two fractions were separated by 100 s. The results suggest that engaging electrosensitization may assist in vivo cancer ablation by reducing the voltage or number of pulses required, or by enabling larger inter-electrode distances without losing the ablation efficiency.

Electroporation-enhanced delivery of nucleic acid vaccines

The naked delivery of nucleic acid vaccines is notoriously inefficient, and an enabling delivery technology is required to direct efficiently these constructs intracellularly. A delivery technology capable of enhancing nucleic acid uptake in both cells in tissues and in culture is electroporation (EP). EP is a physical delivery mechanism that increases the permeability of mammalian cell membranes and allows the trafficking of large macromolecules into the cell. EP has now been used extensively in the clinic and been shown to be an effective method to increase both the uptake of the construct and the breadth and magnitude of the resulting immune responses. Excitingly, 2014 saw the announcement of the first EP-enhanced DNA vaccine Phase II trial demonstrating clinical efficacy. This review seeks to introduce the reader to EP as a technology to enhance the delivery of DNA and RNA vaccines and highlight several published clinical trials using this delivery modality.

Craniopharyngioma

This report is a review of findings on the diagnosis, treatment, clinical course, and prognosis of craniopharyngioma patients. Craniopharyngiomas are rare, partly cystic and calcified embryonic malformations of the sellar/parasellar region with low histological grade (WHO I°). A bimodal age distribution has been shown, with peak incidence rates in childhood-onset at 5-14 years and adult-onset craniopharyngioma at 50-74 years. Clinical manifestations are related to hypothalamic/pituitary deficiencies, visual impairment, and increased intracranial pressure. If the tumor is favorably localized, the therapy of choice is complete resection, with care taken to preserve optical and hypothalamic functions. In patients with unfavorable tumor localization (i.e., hypothalamic involvement), recommended therapy is a limited hypothalamus-sparing surgical strategy followed by local irradiation. Although overall survival rates are high (92%), recurrences and progressions are frequent. Irradiation has proven effective in reducing recurrences and progression, and timing of postsurgical irradiation in childhood-onset cases is currently under investigation in a randomized multinational trial (KRANIOPHARYNGEOM 2007). Anatomical involvement and/or surgical lesions of posterior hypothalamic areas can result in serious quality of life-compromising sequelae such as hypothalamic obesity, psychopathological symptoms, and/or cognitive problems. It is crucial that craniopharyngioma be managed as a frequently chronic disease, providing ongoing care of pediatric and adult patients' clinical and quality of life consequences by experienced multidisciplinary teams.

The E3 ubiquitin protein ligase HERC2 modulates the activity of tumor protein p53 by regulating its oligomerization

The tumor suppressor p53 is a transcription factor that coordinates the cellular response to several kinds of stress. p53 inactivation is an important step in tumor progression. Oligomerization of p53 is critical for its posttranslational modification and its ability to regulate the transcription of target genes necessary to inhibit tumor growth. Here we report that the HECT E3 ubiquitin ligase HERC2 interacts with p53. This interaction involves the CPH domain of HERC2 (a conserved domain within Cul7, PARC, and HERC2 proteins) and the last 43 amino acid residues of p53. Through this interaction, HERC2 regulates p53 activity. RNA interference experiments showed how HERC2 depletion reduces the transcriptional activity of p53 without affecting its stability. This regulation of p53 activity by HERC2 is independent of proteasome or MDM2 activity. Under these conditions, up-regulation of cell growth and increased focus formation were observed, showing the functional relevance of the HERC2-p53 interaction. This interaction was maintained after DNA damage caused by the chemotherapeutic drug bleomycin. In these stressed cells, p53 phosphorylation was not impaired by HERC2 knockdown. Interestingly, p53 mutations that affect its tetramerization domain disrupted the HERC2-p53 interaction, suggesting a role for HERC2 in p53 oligomerization. This regulatory role was shown using cross-linking assays. Thus, the inhibition of p53 activity after HERC2 depletion can be attributed to a reduction in p53 oligomerization. Ectopic expression of HERC2 (residues 2292-2923) confirmed these observations. Together, these results identify HERC2 as a novel regulator of p53 signaling.

Dual time point imaging fluorine-18 flourodeoxyglucose positron emission tomography for evaluation of large loco-regional recurrences of breast cancer treated with electrochemotherapy

Background

Electrochemotherapy is a local anticancer treatment very efficient for treatment of small cutaneous metastases. The method is now being investigated for large cutaneous recurrences of breast cancer that are often confluent masses of malignant tumour with various degrees of inflammation. To this end 18-Flourine-Flourodeoxyglucose-Positron Emission Tomography/Computed Tomography (FDG-PET/CT) could be a method for response evaluation. However, a standard FDG-PET/CT scan cannot differentiate inflammatory tissue from malignant tissue. Dual point time imaging (DTPI) FDG-PET has the potential of doing so. The purpose of this study was to investigate if DTPI FDG-PET/CT could assess response to electrochemotherapy and to assess the optimal timing of imaging.

Patients and methods

Within a phase II clinical trial 11 patients with cutaneous recurrences had FDG-PET/CT scans at three time points: 60 min, 120 min and 180 min after FDG injection. The scans were performed before and 3 weeks after electrochemotherapy.

Results

A significant reduction in maximum standard uptake value at 60 min post injection was seen after treatment. Furthermore a change in the FDG uptake pattern was observed; from increasing uptake in up to 180 min post injection before treatment to stabilization of FDG uptake at 120 min post injection after treatment. The change in FDG uptake pattern over time lead to change of response in three target lesions; two lesions changed from stable metabolic disease to partial metabolic response and one lesion changed from partial metabolic response to stable metabolic disease. To ensure detection of the change in uptake pattern, scanning 60 and 180 min post injection seems optimal.

Conclusions

The present study shows that FDG-PET/CT 60 and 180 min after tracer injection is a promising tool for response evaluation of cutaneous recurrences of breast cancer treated with electrochemotherapy.

Single-cell microarray enables high-throughput evaluation of DNA double-strand breaks and DNA repair inhibitors

A key modality of non-surgical cancer management is DNA damaging therapy that causes DNA double-strand breaks that are preferentially toxic to rapidly dividing cancer cells. Double-strand break repair capacity is recognized as an important mechanism in drug resistance and is therefore a potential target for adjuvant chemotherapy. Additionally, spontaneous and environmentally induced DSBs are known to promote cancer, making DSB evaluation important as a tool in epidemiology, clinical evaluation and in the development of novel pharmaceuticals. Currently available assays to detect double-strand breaks are limited in throughput and specificity and offer minimal information concerning the kinetics of repair. Here, we present the CometChip, a 96-well platform that enables assessment of double-strand break levels and repair capacity of multiple cell types and conditions in parallel and integrates with standard high-throughput screening and analysis technologies. We demonstrate the ability to detect multiple genetic deficiencies in double-strand break repair and evaluate a set of clinically relevant chemical inhibitors of one of the major double-strand break repair pathways, non-homologous end-joining. While other high-throughput repair assays measure residual damage or indirect markers of damage, the CometChip detects physical double-strand breaks, providing direct measurement of damage induction and repair capacity, which may be useful in developing and implementing treatment strategies with reduced side effects.

Multiple brain metastases - current management and perspectives for treatment with electrochemotherapy

Background

Due to the advanced oncological treatments of cancer, an overall increase in cancer incidence, and better diagnostic tools, the incidence of brain metastases is on the rise. This review addresses the current treatment options for patients with multiple brain metastases, presenting electrochemotherapy (ECT) as one of the new experimental treatments for this group of patients.

Conclusions

Neurosurgery, stereotactic surgery, and whole-brain radiotherapy are the evidence-based treatments that can be applied for patients with multiple brain metastases. Treatment with chemotherapy and molecularly targeted agents may also be warranted. Several experimental treatments are emerging, one of which is ECT, an effective cancer treatment comprising electric pulses given by electrodes in the tumor tissue, causing electroporation of the cell membrane, and thereby augmenting uptake and the cytotoxicity of the chemotherapeutic drug bleomycin by 300 times. Preclinical data are promising and the first patient has been treated in an ongoing clinical trial for patients with brain metastases. Perspectives for ECT in the brain include treatment of primary and secondary brain tumors as well as soft tissue metastases elsewhere.

Vasculopathy after intracystic bleomycin administration for a recurrent cystic craniopharyngioma: case report

Intracystic bleomycin (ICB) administration is known to be effective in the treatment of cystic craniopharyngiomas (CRPs) and rarely causes serious complications. The authors report a case of vasculopathy after ICB injection for a recurrent cystic CRP. A 5-year-old boy presented with the cystic recurrence of a CRP. A catheter and Ommaya system were inserted into the cyst, followed by a leakage test 2 weeks later. Bleomycin was delivered at 3 mg per week for 14 weeks (total dose 42 mg). Four months later, the patient's activity decreased and right hemiparesis occurred. Magnetic resonance imaging and cerebral angiography demonstrated a recurrent multicystic mass and infarction at the left middle cerebral artery territory with stenosis/occlusion of the left distal internal carotid artery and posterior cerebral artery. During the operation to remove the recurrent cystic mass, fibrotic stenoocclusion of the left intracranial arteries was identified. The cyst was totally removed. However, additional multiple border zone infarctions occurred in the left hemisphere, and the patient became wheelchair bound. Leakage of ICB was considered as the most probable cause of the cerebral vasculopathy and corresponding infarction. A leakage test may not always guarantee a leakage-free status even if the test is negative. Direct bypass surgery should have been considered to prevent a high risk of postoperative infarction in this case of a recurrent CRP with confirmed vasculopathy.

Intracystic therapies for cystic craniopharyngioma in childhood

INTRODUCTION

Craniopharyngioma of childhood are commonly cystic in nature. An intracystic catheter insertion and subsequent instillation of substances inducing cyst shrinkage seems a beneficial strategy avoiding additional morbidity in a highly vulnerable brain location.

METHODS

A systematic review of the medical literature was performed to identify potentially relevant, all languages articles using Ovid MEDLINE and EMBASE from inception to July 2011 and Cochrane Central Register of Controlled Trials to third quarter 2011. All references were examined for relevancy.

RESULTS

Of 142 unique references, 71 referred to substances used for intracystic craniopharyngioma treatment. General aspects of intracystic catheter insertion as well as response rates, risks, and outcomes of children treated with intracystic radioisotopes, bleomycin, and interferon (IFN) are critically reviewed and an outline for potential future endeavors provided.

CONCLUSION

IFN seems currently the intracystic substance with the best benefit risk ratio. The authors advocate for consensus on prospective data collection and standardized intracystic treatment strategies to allow reliable comparisons and herewith optimize treatment and outcome.

Microsecond and nanosecond electric pulses in cancer treatments

New local treatments based on electromagnetic fields have been developed as non-surgical and minimally invasive treatments of tumors. In particular, short electric pulses can induce important non-thermal changes in cell physiology, especially the permeabilization of the cell membrane. The aim of this review is to summarize the present data on the electroporation-based techniques: electrochemotherapy (ECT), nanosecond pulsed electric fields (nsPEFs), and irreversible electroporation (IRE). ECT is a safe, easy, and efficient technique for the treatment of solid tumors that uses cell-permeabilizing electrical pulses to enhance the activity of a non-permeant (bleomycin) or low permeant (cisplatin) anticancer drug with a very high intrinsic cytotoxicity. The most interesting feature of ECT is its unique ability to selectively kill tumor cells without harming normal surrounding tissue. ECT is already used widely in the clinics in Europe. nsPEFs could represent a drug free, purely electrical cancer therapy. They allow the inhibition of tumor growth, and interestingly, nsPEF can target intracellular organelles. However, many questions remain on the mechanism of action of these pulses. Finally, IRE is a new ablation procedure using pulses that provoke the permanent permeabilization of the cells resulting in their death. This technique does not result in any thermal effect, which is its main advantage in current physical ablation technologies. For both the nsPEF and the IRE, the preservation of the normal tissue, which is characteristic of ECT, has not yet been shown and their safety and efficacy still have to be investigated thoroughly in vivo and in the clinics.

Preclinical validation of electrochemotherapy as an effective treatment for brain tumors

Electrochemotherapy represents a strategy to enhance chemotherapeutic drug uptake by delivering electrical pulses which exceed the dielectric strength of the cell membrane, causing transient formation of structures that enhance permeabilization. Here we show that brain tumors in a rat model can be eliminated by electrochemotherapy with a novel electrode device developed for use in the brain. By using this method, the cytotoxicity of bleomycin can be augmented more than 300-fold because of increased permeabilization and more direct passage of drug to the cytosol, enabling highly efficient local tumor treatment. Bleomycin was injected intracranially into male rats inoculated with rat glia-derived tumor cells 2 weeks before the application of the electrical field (32 pulses, 100 V, 0.1 ms, and 1 Hz). In this model, where presence of tumor was confirmed by magnetic resonance imaging (MRI) before treatment, we found that 9 of 13 rats (69%) receiving electrochemotherapy displayed a complete elimination of tumor, in contrast to control rats treated with bleomycin only, pulses only, or untreated where tumor progression occurred in each case. Necrosis induced by electrochemotherapy was restricted to the treated area, which MRI and histology showed to contain a fluid-filled cavity. In a long-range survival study, treatment side effects seemed to be minimal, with normal rat behavior observed after electrochemotherapy. Our findings suggest that electrochemotherapy may offer a safe and effective new tool to treat primary brain tumors and brain metastases.

Surgical strategies in childhood craniopharyngioma

Craniopharyngiomas are biologically benign lesions (WHO Grade 1) of the sellar and suprasellar region, associated with a serious morbidity. About 50% of these tumors become clinically apparent during childhood. Clinical symptoms include headaches, chiasm syndrome, hydrocephalus, pituitary insufficiencies, and obesity. Growth arrest is a typical symptom in children. The treatment of craniopharyngiomas includes surgery as well as radiotherapy. The goal of surgery varies according to the tumor location and extension and may range from complete resection to biopsy. Surgical complications are well known and cause constant evaluation of surgical strategies. Diencephalic obesity is related to surgical manipulation of hypothalamic tissue. Therefore, a classification system for craniopharyngiomas based on preoperative MRI is suggested by the authors. Recurrences are frequent in craniopharyngiomas, even after complete or gross-total resection. Radiotherapy is therefore recommended to patients with incomplete resections. However, the ideal time for radiotherapy after surgery is under discussion. The treatment of craniopharyngiomas requires an interdisciplinary and multimodal approach. Each patient should receive an individually tailored treatment. Surgically, different approaches as well as different degrees of resection can be considered, depending on tumor location and tumor extension.

Intracystic treatments for craniopharyngioma

Craniopharyngioma is a benign tumor histopathologically and in theory should be curable by radical resection. In practice, this tumor behaves like a chronic disease, with many issues related to the effect of the tumor itself and the various treatments on the adjacent structures, such as the pituitary stalk and gland, hypothalamus, visual apparatus, and suprasellar arteries. A multimodality approach to the management of these tumors may produce the optimal outcome, balancing disease control and quality of life. In this paper, the role of intracystic therapies is reviewed, with the major focus on intracystic bleomycin and interferon-α.