Comparison of Adaptive Neuroprotective Mechanisms of Sulforaphane and its Interconversion Product Erucin in in Vitro and in Vivo Models of Parkinson's Disease.

Several studies suggest that an increase of glutathione (GSH) through activation of the transcriptional nuclear factor (erythroid-derived 2)-like 2 (Nrf2) in the dopaminergic neurons may be a promising neuroprotective strategy in Parkinson's disease (PD). Among Nrf2 activators, isothiocyanate sulforaphane (SFN), derived from precursor glucosinolate present in Brassica vegetables, has gained attention as a potential neuroprotective compound. Bioavailability studies also suggest the contribution of SFN metabolites, including erucin (ERN), to the neuroprotective effects of SFN. Therefore, we compared the in vitro neuroprotective effects of SFN and ERN at the same dose level (5 µM) and oxidative treatment with 6-hydroxydopamine (6-OHDA) in SH-SY5Y cells. The pretreatment of SH-SY5Y cells with SFN recorded a higher (p < 0.05) active nuclear Nrf2 protein (12.0 ± 0.4 vs 8.0 ± 0.2 fold increase), mRNA Nrf2 (2.0 ± 0.3 vs 1.4 ± 0.1 fold increase), total GSH (384.0 ± 9.0 vs 256.0 ± 8.0 µM) levels, and resistance to neuronal apoptosis elicited by 6-OHDA compared to ERN. By contrast, the simultaneous treatment of SH-SY5Y cells with either SFN or ERN and 6-OHDA recorded similar neuroprotective effects with both the isothiocyanates (Nrf2 protein 2.2 ± 0.2 vs 2.1 ± 0.1 and mRNA Nrf2 2.1 ± 0.3 vs 1.9 ± 0.2 fold increase; total GSH 384.0 ± 4.8 vs 352.0 ± 6.4 µM). Finally, in vitro finding was confirmed in a 6-OHDA-PD mouse model. The metabolic oxidation of ERN to SFN could account for their similar neuroprotective effects in vivo, raising the possibility of using vegetables containing a precursor of ERN for systemic antioxidant benefits in a similar manner to SFN.

ANMCO/ISS/AMD/ANCE/ARCA/FADOI/GICR-IACPR/SICI-GISE/SIBioC/SIC/SICOA/SID/SIF/SIMEU/SIMG/SIMI/SISA Joint Consensus Document on cholesterol and cardiovascular risk: diagnostic-therapeutic pathway in Italy.

Atherosclerotic cardiovascular disease still represents the leading cause of death in Western countries. A wealth of scientific evidence demonstrates that increased blood cholesterol levels have a major impact on the outbreak and progression of atherosclerotic plaques. Moreover, several cholesterol-lowering pharmacological agents, including statins and ezetimibe, have proved effective in improving clinical outcomes. This document focuses on the clinical management of hypercholesterolaemia and has been conceived by 16 Italian medical associations with the support of the Italian National Institute of Health. The authors discuss in detail the role of hypercholesterolaemia in the genesis of atherosclerotic cardiovascular disease. In addition, the implications for high cholesterol levels in the definition of the individual cardiovascular risk profile have been carefully analysed, while all available therapeutic options for blood cholesterol reduction and cardiovascular risk mitigation have been explored. Finally, this document outlines the diagnostic and therapeutic pathways for the clinical management of patients with hypercholesterolaemia.

Relationship between Lipid Phenotypes, Overweight, Lipid Lowering Drug Response and KIF6 and HMG-CoA Genotypes in a Subset of the Brisighella Heart Study Population.

The existence of genetic traits might explain the susceptibility to develop hypercholesterolemia and the inter-individual differences in statin response. This study was performed to evaluate whether individuals' polymorphisms in HMG-CoA and KIF6 genes are independently associated with hypercholesterolemia, other lipid-associated traits, and statin response in unselected individuals enrolled in the Brisighella heart study (Survey 2012). A total of 1622 individuals, of which 183 under statin medication, were genotyped for a total of five polymorphisms (KIF6 rs20455, rs9471077, rs9462535; HMG-CoA rs3761740, rs3846662). The relationships between the five loci and clinical characteristics were analyzed. The principal basic parameters calculated on 12 h fasting blood included total cholesterol (TC), High Density Lipoprotein Cholesterol (HDL-C), Low-Density Lipoprotein Cholesterol (LDL-C), and triglycerides (TG). Hypercholesterolemia was defined as a TC >200 mg/dL or use of lipid-lowering medication. 965 individuals were characterized by hypercholesterolemia; these subjects were significantly older (p < 0.001), with body mass index (BMI) and waist circumference significantly higher (p < 0.001) compared to the others. HMG-CoA rs3846662 GG genotype was significantly over-represented in the hypercholesterolemic group (p = 0.030). HMG-CoA rs3846662 genotype was associated with the level of TC and LDL-C. Furthermore, in the same subset of untreated subjects, we observed a significant correlation between the KIF6 rs20455 and HDL-C. KIF6 variants were associated with a significantly lower (rs20455) or higher (rs9471077 and rs9462535) risk of obesity, in males only. No association between responsiveness to statins and the polymorphisms under investigation were observed. Our results showed associations between HMG-CoA rs3846662 and KIF6 rs20455 and lipid phenotypes, which may have an influence on dyslipidemia-related events. Moreover, this represents the first study implicating KIF6 variants with obesity in men, and point to the possible involvement of this genetic locus in the known gender-related differences in coronary artery disease.

[ANMCO/ISS/AMD/ANCE/ARCA/FADOI/GICR-IACPR/SICI-GISE/SIBioC/SIC/SICOA/SID/SIF/SIMEU/SIMG/SIMI/SISA Consensus document. Hypercholesterolemia and cardiovascular risk: diagnostic and therapeutic pathways in Italy]. / Documento di consenso intersocietario ANMCO/ISS/AMD/ANCE/ARCA/FADOI/ GICR-IACPR/SICI-GISE/SIBioC/SIC/SICOA/ SID/SIF/SIMEU/SIMG/SIMI/SISA Colesterolo e rischio cardiovascolare: percorso diagnostico-terapeutico in Italia.

Atherosclerotic cardiovascular disease still represents the leading cause of death in western countries. A wealth of scientific evidence demonstrates that increased blood cholesterol levels have a major impact on the outbreak and progression of atherosclerotic plaques. Moreover, several cholesterol-lowering pharmacological agents, including statins and ezetimibe, have proven effective in improving clinical outcomes. This document is focused on the clinical management of hypercholesterolemia and has been conceived by 16 Italian medical associations with the support of the Italian National Institute of Health. The authors have considered with particular attention the role of hypercholesterolemia in the genesis of atherosclerotic cardiovascular disease. Besides, the implications of high cholesterol levels in the definition of the individual cardiovascular risk profile have been carefully analyzed, while all available therapeutic options for blood cholesterol reduction and cardiovascular risk mitigation have been considered. Finally, this document outlines the diagnostic and therapeutic pathways for the clinical management of patients with hypercholesterolemia.

The Water to Water Cycles in Microalgae.

In oxygenic photosynthesis, light produces ATP plus NADPH via linear electron transfer, i.e. the in-series activity of the two photosystems: PSI and PSII. This process, however, is thought not to be sufficient to provide enough ATP per NADPH for carbon assimilation in the Calvin-Benson-Bassham cycle. Thus, it is assumed that additional ATP can be generated by alternative electron pathways. These circuits produce an electrochemical proton gradient without NADPH synthesis, and, although they often represent a small proportion of the linear electron flow, they could have a huge importance in optimizing CO2 assimilation. In Viridiplantae, there is a consensus that alternative electron flow comprises cyclic electron flow around PSI and the water to water cycles. The latter processes include photosynthetic O2 reduction via the Mehler reaction at PSI, the plastoquinone terminal oxidase downstream of PSII, photorespiration (the oxygenase activity of Rubisco) and the export of reducing equivalents towards the mitochondrial oxidases, through the malate shuttle. In this review, we summarize current knowledge about the role of the water to water cycles in photosynthesis, with a special focus on their occurrence and physiological roles in microalgae.

Neuroprotection by 6-(methylsulfinyl)hexyl isothiocyanate in a 6-hydroxydopamine mouse model of Parkinson׳s disease.

A number of pathogenic factors have been implicated in the progression of Parkinson׳s disease (PD), including oxidative stress, mitochondrial dysfunction, inflammation, excitotoxicity, and signals mediating apoptosis cascade. 6-(methylsulfinyl)hexyl isothiocyanate (6-MSITC) is a major component in wasabi, a very popular spice in Japan and a member of the Brassica family of vegetables. This study was designed to investigate the neuroprotective effects of 6-MSITC in a PD mouse model. Mice were treated with 6-MSITC (5mg/kg twice a week) for four weeks after the unilateral intrastriatal injection of 6-hydroxydopamine (6-OHDA). On the 28th day, 6-OHDA-injected mice showed behavioral impairments, a significant decrease in tyrosine hydroxylase (TH) and an increase in apoptosis. In addition, lesioned mice showed reduced glutathione levels and glutathione-S-transferase and glutathione reductase activities. Notably, 6-MSITC demonstrated neuroprotective effects in our experimental model strongly related to the preservation of functional nigral dopaminergic neurons, which contributed to the reduction of motor dysfunction induced by 6-OHDA. Furthermore, this study provides evidence that the beneficial effects of 6-MSITC could be attributed to the decrease of apoptotic cell death and to the activation of glutathione-dependent antioxidant systems. These findings may render 6-MSITC as a promising molecule for further pharmacological studies on the investigation for disease-modifying treatment in PD.

Antileukemic activity of sulforaphane in primary blasts from patients affected by myelo- and lympho-proliferative disorders and in hypoxic conditions.

Sulforaphane is a dietary isothiocyanate found in cruciferous vegetables showing antileukemic activity. With the purpose of extending the potential clinical impact of sulforaphane in the oncological field, we investigated the antileukemic effect of sulforaphane on blasts from patients affected by different types of leukemia and, taking into account the intrinsically hypoxic nature of bone marrow, on a leukemia cell line (REH) maintained in hypoxic conditions. In particular, we tested sulforaphane on patients with chronic lymphocytic leukemia, acute myeloid leukemia, T-cell acute lymphoblastic leukemia, B-cell acute lymphoblastic leukemia, and blastic NK cell leukemia. Sulforaphane caused a dose-dependent induction of apoptosis in blasts from patients diagnosed with acute lymphoblastic or myeloid leukemia. Moreover, it was able to cause apoptosis and to inhibit proliferation in hypoxic conditions on REH cells. As to its cytotoxic mechanism, we found that sulforaphane creates an oxidative cellular environment that induces DNA damage and Bax and p53 gene activation, which in turn helps trigger apoptosis. On the whole, our results raise hopes that sulforaphane might set the stage for a novel therapeutic principle complementing our growing armature against malignancies and advocate the exploration of sulforaphane in a broader population of leukemic patients.

Sulforaphane induces apoptosis in rhabdomyosarcoma and restores TRAIL-sensitivity in the aggressive alveolar subtype leading to tumor elimination in mice.

Rhadbomyosarcoma (RMS) is the most common soft-tissue sarcoma in children and is subdivided in the embryonal (ERMS) and alveolar (ARMS) subtypes, the latter being associated with the worst prognosis. We report that sulforaphane (SFN), a broccoli-derived anticancer isothiocyanate, causes dose- and time-dependent growth inhibition and apoptosis in both ERMS and ARMS cells. In ARMS, SFN induced the modulation of expression of crucial genes and proteins: mRNA and protein levels of PAX3-FKHR, MYCN, and MET decreased, while those of p21 and TRAIL-receptor DR5 (but not DR4) increased. Since DR5 expression increased specifically in ARMS, we treated ARMS cells with TRAIL, SFN, or their combination. While ARMS cells (RH30 and RH4) proved to be TRAIL-resistant, SFN restored their sensitivity to TRAIL-induced cell-growth inhibition, leading to a stronger effect in combination with TRAIL. ARMS cells transfected with siDR5 showed that SFN-induced DR5 acts as a key regulator, being directly related to the TRAIL-induced cell-growth inhibition. The in vivo anti-tumor activity of SFN and TRAIL was evaluated in a xenograft murine model of ARMS through microPET. The results showed that the systemic treatment (3 wk) of mice with SFN or TRAIL as single agents only delayed tumor evolution, while the combined treatment of SFN and TRAIL led to tumor elimination. These findings indicate that SFN triggers the apoptotic pathway in both alveolar and embryonal rhabdomyosarcomas and that combined treatment with SFN and TRAIL might be a promising therapy for the aggressive alveolar subtype.

Micronucleus frequency in human peripheral blood lymphocytes as a biomarker for the early detection of colorectal cancer risk.

The early detection of colorectal cancer (CRC) can significantly improve the prognosis of affected patients. The loss of genomic stability and the resulting gene alteration play an important role in the molecular pathological steps that occur early in tumorigenesis of CRC. Thus, the identification of non-invasive biomarkers, whose function may provide useful insights into critical early events in the CRC process, is of great interest. In this regard, micronucleus (MN) frequency in peripheral blood lymphocytes (PBL) has become one of the most established biomarkers for studying DNA damage in the human population. This study investigated the MN frequency in the PBL of 82 subjects (30 females and 52 males; aged 50-70 years) who were participating in a screening programme for CRC prevention. All 82 patients were positive in fecal occult blood tests and they were subsequently classified, according to colonoscopy and histological findings, as patients with CRC, patients with colon polyps or subjects without intestinal lesion, referred to as study controls. This study also examined the relationship between the plasma clastogenic activity and the frequency of micronuclei of the study population. The MN frequency was significantly higher in CRC patients than in both colon polyp patients (16.82±6.56 versus 12.23±1.88; P = 0.002) and controls (16.82±6.56 versus 8.00±1.77; P < 0.001). An increased MN frequency was detected in the lymphocytes of the polyp group in comparison to the control group, although this was lower than that observed in CRC patients (12.23±1.88 versus 8.00±1.77; P < 0.001). In the overall study population, the increase of MN frequency, which was observed in the lymphocytes of the subjects involved, was significantly associated with the clastogenic activity detected in their plasma (r = 0.594, P < 0.001). Overall, the results suggest that the MN test can become a promising biomarker for the early detection of CRC.

Inflammation-induced alteration of astrocyte mitochondrial dynamics requires autophagy for mitochondrial network maintenance.

Accumulating evidence suggests that changes in the metabolic signature of astrocytes underlie their response to neuroinflammation, but how proinflammatory stimuli induce these changes is poorly understood. By monitoring astrocytes following acute cortical injury, we identified a differential and region-specific remodeling of their mitochondrial network: while astrocytes within the penumbra of the lesion undergo mitochondrial elongation, those located in the core-the area invaded by proinflammatory cells-experience transient mitochondrial fragmentation. In brain slices, proinflammatory stimuli reproduced localized changes in mitochondrial dynamics, favoring fission over fusion. This effect was triggered by Drp1 phosphorylation and ultimately resulted in reduced respiratory capacity. Furthermore, maintenance of the mitochondrial architecture critically depended on the induction of autophagy. Deletion of Atg7, required for autophagosome formation, prevented the reestablishment of tubular mitochondria, leading to marked reactive oxygen species accumulation and cell death. Thus, our data reveal autophagy to be essential for regenerating astrocyte mitochondrial networks during inflammation.

Red chicory (Cichorium intybus L. cultivar) as a potential source of antioxidant anthocyanins for intestinal health.

Fruit- and vegetable-derived foods have become a very significant source of nutraceutical phytochemicals. Among vegetables, red chicory (Cichorium Intybus L. cultivar) has gained attention for its content of phenolic compounds, such as the anthocyanins. In this study, we evaluated the nutraceutical effects, in terms of antioxidant, cytoprotective, and antiproliferative activities, of extracts of the whole leaf or only the red part of the leaf of Treviso red chicory (a typical Italian red leafy plant) in various intestinal models, such as Caco-2 cells, differentiated in normal intestinal epithelia and undifferentiated Caco-2 cells. The results show that the whole leaf of red chicory can represent a good source of phytochemicals in terms of total phenolics and anthocyanins as well as the ability of these phytochemicals to exert antioxidant and cytoprotective effects in differentiated Caco-2 cells and antiproliferative effects in undifferentiated Caco-2 cells. Interestingly, compared to red chicory whole leaf extracts, the red part of leaf extracts had a significantly higher content of both total phenolics and anthocyanins. The same extracts effectively corresponded to an increase of antioxidant, cytoprotective, and antiproliferative activities. Taken together, these findings suggest that the red part of the leaf of Treviso red chicory with a high content of antioxidant anthocyanins could be interesting for development of new food supplements to improve intestinal health.

Neuroprotective effect of sulforaphane in 6-hydroxydopamine-lesioned mouse model of Parkinson's disease.

Parkinson's disease (PD) is characterized by the selective loss of dopaminergic nigrostriatal neurons, which leads to disabling motor disturbances. Sulforaphane (SFN), found in cruciferous vegetables, is a potent indirect antioxidant and recent advances have shown its neuroprotective activity in various experimental models of neurodegeneration. This study was undertaken to examine the effects of SFN on behavioral changes and dopaminergic neurotoxicity in mice exposed to 6-hydroxydopamine (6-OHDA). For this purpose, mice were treated with SFN (5mg/kg twice a week) for four weeks after the unilateral intrastriatal injection of 6-OHDA. The increase in 6-OHDA-induced rotations and deficits in motor coordination were ameliorated significantly by SFN treatment. In addition, SFN protected 6-OHDA-induced apoptosis via blocking DNA fragmentation and caspase-3 activation. These results were further supported by immunohistochemical findings in the substantia nigra that showed that SFN protected neurons from neurotoxic effects of 6-OHDA. The neuroprotective effect of SFN may be attributed to its ability to enhance glutathione levels and its dependent enzymes (glutathione-S-transferase and glutathione reductase) and to modulate neuronal survival pathways, such as ERK1/2, in the brain of mice. These results suggest that SFN may potentially be effective in slowing down the progression of idiopathic PD by the modulation of oxidative stress and apoptotic machinery.

Polymorphisms in OCTN1 and OCTN2 transporters genes are associated with prolonged time to progression in unresectable gastrointestinal stromal tumours treated with imatinib therapy.

The two basic mainstays of gastrointestinal stromal tumours (GIST) treatment are surgery and imatinib, a selective tyrosine kinase inhibitor that allows achieving a stable or responding disease in about 80% of patients with unresectable/metastatic GIST. Response to imatinib mainly depends from KIT and PDGFRα mutational status. Nevertheless, some patients with a potentially responsive genotype do not respond, and others develop a pattern of resistance to imatinib which is not associated with secondary mutations. This emphasizes the presence of mechanisms of resistance other than the receptor-related genotype, and the need of biological predictors to select the optimal therapeutic strategy, particularly now that other potent inhibitors are available. We investigated a panel of 31 polymorphisms in 11 genes, potentially associated with the pharmacogenetics of imatinib, in a group of 54 unresectable/metastatic GISTs treated with imatinib 400mg daily as first line therapy. Included in this analysis were polymorphisms in the transporters' family SLC22, SLCO, ABC, and in the metabolizing genes CYP-3A4 and -3A5. Time to progression was significantly improved in presence of the C allele in SLC22A4 (OCTN1 rs1050152), and the two minor alleles (G) in SLC22A5 (OCTN2 rs2631367 and rs2631372). Importantly, multivariate analysis, adjusting for age, gender, KIT/PDGFRα mutational status, and tumour size, revealed that all the three genotypes maintained independent predictive significance. In conclusion, in this study we showed that SLC22A4 and SLC22A5 genotypes may be an important predictor of time to progression in GIST patients receiving imatinib therapy. Further investigations are required in an attempt to further personalize GIST therapy.

Association between imatinib transporters and metabolizing enzymes genotype and response in newly diagnosed chronic myeloid leukemia patients receiving imatinib therapy.

Imatinib has so far been the first-choice treatment in chronic myeloid leukemia with excellent results. However, only a proportion of patients achieve major molecular response - hence the need to find biological predictors of outcome to select the optimal therapeutic strategy now that more potent inhibitors are available. We investigated a panel of 20 polymorphisms in seven genes, potentially associated with the pharmacogenetics of imatinib, in a subset of 189 patients with newly diagnosed chronic myeloid leukemia enrolled in the TOPS trial. The analysis included polymorphisms in the transporters hOCT1, MDR1, ABCG2, OCTN1, and OATP1A2, and in the metabolizing genes CYP3A4 and CYP3A5. In the overall population, the OCTN1 C allele (rs1050152), a simple combination of polymorphisms in the hOCT1 gene and another combination in the genes involved in imatinib uptake were significantly associated with major molecular response. The combination of polymorphisms in imatinib uptake was also significantly associated with complete molecular response. Analyses restricted to Caucasians highlighted the significant association of MDR1 CC (rs60023214) genotype with complete molecular response. We demonstrate the usefulness of a pharmacogenetic approach for stratifying patients with chronic myeloid leukemia according to their likelihood of achieving a major or complete molecular response to imatinib. This represents an attractive opportunity for therapy optimization, worth testing in clinical trials.

Neuroprotective effects of erucin against 6-hydroxydopamine-induced oxidative damage in a dopaminergic-like neuroblastoma cell line.

Oxidative stress (OS) contributes to the cascade leading to the dysfunction or death of dopaminergic neurons during Parkinson's disease (PD). A strategy to prevent the OS of dopaminergic neurons may be the use of phytochemicals as inducers of endogenous antioxidants and phase 2 enzymes. In this study, we demonstrated that treatment of the dopaminergic-like neuroblastoma SH-SY5Y cell line with isothiocyanate erucin (ER), a compound of cruciferous vegetables, resulted in significant increases of both total glutathione (GSH) levels and total antioxidant capacity at the cytosolic level. The increase of GSH levels was associated with an increase in the resistance of SH-SY5Y cells to neuronal death, in terms of apoptosis, induced by 6-hydroxydopamine (6-OHDA). The pretreatment of SH-SY5Y cells with ER was also shown to prevent the redox status impairment, in terms of intracellular ROS and O(2) (•-) formation, and loss of mitochondrial membrane potential, early events that are initiators of the apoptotic process, induced by 6-OHDA. Last, the antiapoptotic and antioxidant effects of ER were abolished by buthionine sulfoximine, supporting the main role of GSH in the neuroprotective effects recorded by ER. These results suggest that ER may prevent the oxidative damage induced by 6-OHDA.

Metabolic and toxicological considerations of botanicals in anticancer therapy.

INTRODUCTION: Cancer is a complex disease, characterized by redundant aberrant signaling pathways as a result of genetic perturbations at different levels. Botanicals consist of a complex mixture of constituents and exhibit pharmacological effects by the interaction of many phytochemicals. The multitarget nature of botanicals could, therefore, be a relevant strategy to address the biological complexity that characterizes tumors. AREAS COVERED: This article reviews the current status of botanicals in the oncological field and the challenges associated with their complex nature. EXPERT OPINION: Botanicals are an important new pharmacological strategy, which are potentially exploitable in the oncological area but are characterized by a number of problems still unresolved. Content variation of products is one of the primary problems with botanicals and, consequently, there is a concern about the therapeutic consistency in marketed batches. Furthermore, metabolic interactions with antineoplastic drugs and the genotoxic potential of botanicals need to be properly addressed throughout the various phases of botanical drug development. These issues not only pose a serious problem to the approvability of those botanical products as new drugs but also present as a limitation to their post-approval clinical use.

Sulforaphane potentiates RNA damage induced by different xenobiotics.

BACKGROUND: The isothiocyanate sulforaphane (SFN) possesses interesting anticancer activities. However, recent studies reported that SFN promotes the formation of reactive oxygen species (ROS) as well as DNA breakage. METHODOLOGY/PRINCIPAL FINDINGS: We investigated whether SFN is able to damage RNA, whose loss of integrity was demonstrated in different chronic diseases. Considering the ability of SFN to protect from genotoxicity, we also examined whether SFN is able to protect from RNA damage induced by different chemicals (doxorubicin, spermine, S-nitroso-N-acetylpenicillamine, H(2)O(2)). We observed that SFN was devoid of either RNA damaging and RNA protective activity in human leukemic cells. It was able to potentiate the RNA damage by doxorubicin and spermine. In the first case, the effect was attributable to its ability of modulating the bioreductive activation of doxorubicin. For spermine, the effects were mainly due to its modulation of ROS levels produced by spermine metabolism. As to the cytotoxic relevance of the RNA damage, we found that the treatment of cells with a mixture of spermine or doxorubicin plus SFN increased their proapoptotic potential. Thus it is conceivable that the presence of RNA damage might concur to the overall toxic response induced by a chemical agent in targeted cells. CONCLUSIONS/SIGNIFICANCE: Since RNA is emerging as a potential target for anticancer drugs, its ability to enhance spermine- and doxorubicin-induced RNA damage and cytotoxicity could represent an additional mechanism for the potentiating effects of SFN associated with anticancer drugs.

Environmental exposure to benzene, micronucleus formation and polymorphisms in DNA-repair genes: a pilot study.

This report is part of a biomarker study conducted in an Italian population with exposure to environmental benzene ranging from 1.43 to 31.41 µg/m³ (values from personal sampling). DNA damage induced by benzene is the crucial mechanism of its genotoxicity, which leads to chronic benzene poisoning, haematotoxicity and leukaemia. Therefore, genetic variation in DNA-repair genes may modulate susceptibility to benzene-induced DNA damage. In light of this, the effects of polymorphisms in DNA-repair genes (APEX1, hOGG1, NBS1, XPD, XRCC1, and XRCC3) on micronucleus (MN) formation as a biomarker of early biological effects were evaluated. A significantly higher median MN frequency was recorded in traffic wardens than in controls. However, none of the analysed polymorphisms was significantly associated with the median MN frequency. A gene-gender interaction was observed for the APEX1 genotype. The APEX1 variant genotype was associated with significantly lower median MN frequency in men, not in women. Statistical analysis did not reveal any association between the score of the protective alleles - hypothetically pushing the pathway towards optimal DNA-damage repair - and MN. Even though there are some limitations in the study, our results indicate that the general population may be exposed to benzene concentrations higher than the threshold level for air-quality standards in the European Union of 10 µg/m³. Furthermore, urban traffic wardens are exposed to significantly higher levels of benzene than individuals spending most of the time indoors. This higher exposure may contribute to DNA damage, suggesting that benzene might be implicated both as an environmental and occupational risk factor in leukaemia and other haematological diseases. In conclusion, this study suggest the need for (i) regular monitoring of traffic wardens for possible exposure to benzene, as a precautionary step to reduce the associated health risks, and (ii) more comprehensive studies in order to better elucidate the involvement of APEX1 genotypes in benzene genotoxicity.

Antitumor activity of sustained N-myc reduction in rhabdomyosarcomas and transcriptional block by antigene therapy.

PURPOSE: Rhabdomyosarcomas are a major cause of cancer death in children, described with MYCN amplification and, in the alveolar subtype, transcription driven by the PAX3-FOXO1 fusion protein. Our aim was to determine the prevalence of N-Myc protein expression and the potential therapeutic effects of reducing expression in rhabdomyosarcomas, including use of an antigene strategy that inhibits transcription. EXPERIMENTAL DESIGN: Protein expression was assessed by immunohistochemistry. MYCN expression was reduced in representative cell lines by RNA interference and an antigene peptide nucleic acid (PNA) oligonucleotide conjugated to a nuclear localization signal peptide. Associated gene expression changes, cell viability, and apoptosis were analyzed in vitro. As a paradigm for antigene therapy, the effects of systemic treatment of mice with rhabdomyosarcoma cell line xenografts were determined. RESULTS: High N-Myc levels were significantly associated with genomic amplification, presence of the PAX3/7-FOXO1 fusion genes, and proliferative capacity. Sustained reduction of N-Myc levels in all rhabdomyosarcoma cell lines that express the protein decreased cell proliferation and increased apoptosis. Positive feedback was shown to regulate PAX3-FOXO1 and N-Myc levels in the alveolar subtype that critically decrease PAX3-FOXO1 levels on reducing N-Myc. Pharmacologic systemic administration of the antigene PNA can eliminate alveolar rhabdomyosarcoma xenografts in mice, without relapse or toxicity. CONCLUSION: N-Myc, with its restricted expression in non-fetal tissues, is a therapeutic target to treat rhabdomyosarcomas, and blocking gene transcription using antigene oligonucleotide strategies has therapeutic potential in the treatment of cancer and other diseases that has not been previously realized in vivo.

Mitochondrial pathway mediates the antileukemic effects of Hemidesmus indicus, a promising botanical drug.

BACKGROUND: Although cancers are characterized by the deregulation of multiple signalling pathways, most current anticancer therapies involve the modulation of a single target. Because of the enormous biological diversity of cancer, strategic combination of agents targeted against the most critical of those alterations is needed. Due to their complex nature, plant products interact with numerous targets and influence several biochemical and molecular cascades. The interest in further development of botanical drugs has been increasing steadily and the FDA recently approved the first new botanical prescription drug. The present study is designed to explore the potential antileukemic properties of Hemidesmus indicus with a view to contributing to further development of botanical drugs. Hemidesmus was submitted to an extensive in vitro preclinical evaluation. METHODOLOGY/PRINCIPAL FINDINGS: A variety of cellular assays and flow cytometry, as well as a phytochemical screening, were performed on different leukemic cell lines. We have demonstrated that Hemidesmus modulated many components of intracellular signaling pathways involved in cell viability and proliferation and altered the protein expression, eventually leading to tumor cell death, mediated by a loss of mitochondrial transmembrane potential and increased Bax/Bcl-2 ratio. ADP, adenine nucleotide translocator and mitochondrial permeability transition pore inhibitors did not reverse Hemidesmus-induced mitochondrial depolarization. Hemidesmus induced a significant [Ca(2+)](i) raise through the mobilization of intracellular Ca(2+) stores. Moreover, Hemidesmus significantly enhanced the antitumor activity of three commonly used chemotherapeutic drugs (methotrexate, 6-thioguanine, cytarabine). A clinically relevant observation is that its cytotoxic activity was also recorded in primary cells from acute myeloid leukemic patients. CONCLUSIONS/SIGNIFICANCE: These results indicate the molecular basis of the antileukemic effects of Hemidesmus and identify the mitochondrial pathways and [Ca(2+)](i) as crucial actors in its anticancer activity. On these bases, we conclude that Hemidesmus can represent a valuable tool in the anticancer pharmacology, and should be considered for further investigations.