Renata Alleva

In vivo supplementation with coenzyme Q10 enhances the recovery of human lymphocytes from oxidative DNA damage

We investigated the effect of in vitro and in vivo CoQ10 supplementation on the recovery of lymphocytes from oxidative DNA damage. Furthermore, we investigated whether CoQ10 supplementation modulates the activity of DNA repair enzymes by using cellular extracts from lymphocytes. Exposure of lymphocytes to oxidizing agents leads to an increase of DNA strand breaks, oxidized purines, and pyrimidines. Enrichment of cells with CoQ10 prevents DNA strand‐break formation and affects the kinetics of repair, which occurs faster in enriched than in native lymphocytes. In contrast, CoQ10 supplementation neither prevents endogenous formation of oxidized bases nor affects their repair. DNA repair enzyme activity is enhanced by in vivo CoQ10 supplementation. Changes in the redox state of several transcriptional factors have been proposed as mechanisms regulating cell proliferation and apoptosis. Because CoQ10 is mainly present as ubiquinol‐10, both in plasma and lymphocytes, it can feasibly modulate the intracellular redox potential involved in the regulation of gene expression. The redox mechanism implicated in the enzyme transactivation could explain the property of CoQ10 to enhance the DNA repair activity and protect DNA from oxidative damage.

Vitamin E analogues: a new class of inducers of apoptosis with selective anti-cancer effects.

In spite of unrelenting effort, the net incidence of neoplastic diseases appears not to have been curbed. While some types of cancer have been suppressed significantly, others are either stagnating or on the increase. Therefore, the need for a cure is imperative, in particularly a drug or combination of drugs that would be selective for malignant cells, i.e. with as low secondary toxicity as possible. Recent data strongly suggest that analogues of vitamin E, epitomised by the most studied alpha-tocopheryl succinate (alpha-TOS), may meet the need for the coveted drugs with a selective anti-neoplastic effect. The reasons for this optimism are reviewed in this article.

Coenzyme Q blocks biochemical but not receptor-mediated apoptosis by increasing mitochondrial antioxidant protection

Generation of free radicals is often associated with the induction and progression of apoptosis. Therefore, antioxidants can prove anti‐apoptotic, and can help to elucidate specific apoptotic pathways. Here we studied whether coenzyme Q, present in membranes in reduced (ubiquinol) or oxidised (ubiquinone) forms, can affect apoptosis induced by various stimuli. Exposure of Jurkat cells to α‐tocopheryl succinate (α‐TOS), hydrogen peroxide, anti‐Fas IgM or TRAIL led to induction of apoptosis. Cell death due to the chemical agents was suppressed in cells enriched with the reduced form of coenzyme Q. However, coenzyme Q did not block cell death induced by the immunological agents. Ubiquinol‐10 inhibited reactive oxygen species (ROS) generation in cells exposed to α‐TOS, and a mitochondrially targeted coenzyme Q analogue also blocked apoptosis triggered by α‐TOS or hydrogen peroxide. Therefore, it is plausible that ubiquinol‐10 protects cells from chemically‐induced apoptosis by acting as an antioxidant in mitochondria. Our results also indicate that generation of free radicals may not be a critical step in induction of apoptosis by immunological agents.

α-Tocopheryl succinate induces DR4 and DR5 expression by a p53-dependent route: Implication for sensitisation of resistant cancer cells to TRAIL apoptosis

We evaluated the ability of α‐tocopheryl succinate (α‐TOS) to sensitise TRAIL‐resistant malignant mesothelioma (MM) cells to TRAIL‐induced apoptosis. We show that α‐TOS activates expression of DR4/DR5 in a p53‐dependent manner and re‐establishes sensitivity of resistant MM cells to TRAIL‐mediated apoptosis, as documented in p53wt MM cells but not in their p53null counterparts. MM cells selected for TRAIL resistance expressed low cell surface levels of DR4 and DR5. Treatment with sub‐lethal doses of α‐TOS restored expression of DR4 and DR5. The ability of α‐TOS to modulate expression of pro‐apoptotic genes may play a role in sensitisation of tumour cells to immunological stimuli.

α-Tocopheryl succinate and TRAIL selectively synergise in induction of apoptosis in human malignant mesothelioma cells

Malignant mesothelioma (MM) is a fatal type of neoplasia with poor therapeutic prognosis, largely due to resistance to apoptosis. We investigated the apoptotic effect of α-tocopheryl succinate (α-TOS), a strong proapoptotic agent, in combination with the immunological apoptogen TNF-related apoptosis-inducing ligand (TRAIL) on both MM and nonmalignant mesothelial cells, since MM cells show low susceptibility to the clinically intriguing TRAIL. All MM cell lines tested were sensitive to α-TOS-induced apoptosis, and exerted high sensitivity to TRAIL in the presence of subapoptotic doses of the vitamin E analogue. Neither TRAIL or α-TOS alone or in combination caused apoptosis in nonmalignant mesothelial cells. Isobologram analysis of the cytotoxicity assays revealed a synergistic interaction between the two agents in MM cells and their antagonistic effect in nonmalignant mesothelial cells. TRAIL-induced apoptosis and its augmentation by α-TOS were inhibited by the caspase-8 inhibitor Z-IETD-FMK and the pan-caspase inhibitor Z-VAD-FMK. Activation of caspase-8 was required to induce apoptosis, which was amplified by α-TOS via cytochrome c release following Bid cleavage, with ensuing activation of caspase-9. Enhancement of TRAIL-induced apoptosis in MM cells by α-TOS was also associated with upregulation of the TRAIL cognate death receptors DR4 and DR5. Our results show that α-TOS and TRAIL act in synergism to kill MM cells via mitochondrial pathway, and are nontoxic to nonmalignant mesothelial cells. These findings are indicative of a novel strategy for treatment of thus far fatal MM.

Profiling Tumor-Associated Markers for Early Detection of Malignant Mesothelioma: An Epidemiologic Study

Improved detection methods for diagnosis of asymptomatic malignant mesothelioma (MM) are essential for an early and reliable detection and treatment of this type of neoplastic disease. Thus, focus has been on finding tumor markers in the blood that can be used for noninvasive detection of MM. Ninety-four asbestos-exposed subjects defined at high risk, 22 patients with MM, and 54 healthy subjects were recruited for evaluation of the clinical significance of 8-hydroxy-2′-deoxyguanosine (8OHdG) in WBCs and plasma concentrations of soluble mesothelin-related peptides (SMRPs), angiogenic factors [platelet-derived growth factor β, hepatocyte growth factor, basic fibroblast growth factor, and vascular endothelial growth factor β (VEGFβ)], and matrix proteases [matrix metalloproteinase (MMP) 2, MMP9, tissue inhibitor of metalloproteinase (TIMP) 1, and TIMP2] for potential early detection of MM. The area under receiver operating characteristic (ROC) curves indicate that 8OHdG levels can discriminate asbestos-exposed subjects from healthy controls but not from MM patients. Significant area under ROC curve values were found for SMRPs, discriminating asbestos-exposed subjects from MM patients but not from healthy controls. Except for platelet-derived growth factor β, the hepatocyte growth factor, basic fibroblast growth factor, and VEGFβ can significantly differentiate high-risk individuals from healthy control and cancer groups. No diagnostic value was observed for MMP2, MMP9, TIMP1, and TIMP2. In addition to the diagnostic performance defined by the ROC analysis, the sensitivity and specificity results of markers with clinical significance were calculated at defined cutoffs. The combination of 8OHdG, VEGFβ, and SMRPs best distinguished the individual groups, suggesting a potential indicator of early and advanced MM cancers. The combination of blood biomarkers and radiographic findings could be used to stratify the risk of mesothelioma in asbestos-exposed populations. (Cancer Epidemiol Biomarkers Prev 2008;17(1):163–70)

Relationship of job satisfaction, psychological distress and stress-related biological parameters among healthy nurses: a longitudinal study.

Relationship of Job Satisfaction, Psychological Distress and Stress‐Related Biological Parameters among Healthy Nurses: A Longitudinal Study: Monica Amati, et al. Department of Molecular Pathology and Innovative Therapies, Clinic of Occupational Medicine, Polytechnic University of Marche, Italy

In vitro effect of aspartame in angiogenesis induction

Aspartame (APM) is the most widely used artificial sweetener and is added to a wide variety of foods, beverages, drugs, and hygiene products. In vitro and in vivo tests have reported contradictory data about APM genotoxicity. We evaluated the angiogenic effect of APM in an in vitro model using blood vessel development assay (Angio-Kit), cultured endothelial cells and fibroblasts. The release of IL-6, VEGF-A, and their soluble receptors sIL-R6 and sVEGFR-2 were determined over time in the conditioned medium of the Angio-Kit system, endothelial cells and cell lines with fibroblast properties after APM treatment. Reactive oxygen species (ROS) formation, cell viability, and stimulation of the extracellular signal-regulated kinases (erk1/2) and protein p38 were also evaluated. Exposure to APM induced blood vessel formation. ROS production was observed in endothelial cells after APM treatment, which was associated with a slight cell cytotoxicity. Neither intracellular ROS formation nor cell death was observed in fibroblasts. APM increases the levels of inflammatory mediator IL-6, VEGF and their soluble receptors released from endothelial cells into the medium. APM treatment induces VEGF-pathway activation by erk1/2 and p38 phosphorylation. APM at low doses is an angiogenic agent that induces regenerative cytokine production leading to the activation of MAPKs and resulting in the formation of new blood vessels.

Malignant Mesothelioma: Biology, Diagnosis and Therapeutic Approaches

Malignant mesothelioma (MM) is an aggressive neoplasm of serosal cavities, which is resistant to conventional therapy, with patient survival from presentation of <12 months. MM remains a universally fatal disease of increasing incidence worldwide. Although the main risk factor is asbestos exposure, other factors, Simian virus 40 infection and inheritance of susceptibility genes, likely play a role. Asbestos-related carcinogenic process is primarily based on the interaction between susceptibility (genetic and acquired) and exposure to carcinogenic environmental agents. Asbestos-induced carcinogenesis includes generation of reactive oxygen species, which induce DNA strand breaks and oxidant-induced base modifications to DNA. Persistent oxidative DNA damage can alter signaling cascades, gene expression, induce or arrest transcription, and increase replication errors and genomic instability. The long promotion phase observed in MM pathogenesis and the absence of early symptoms both contribute to late diagnosis of the disease. This results in delayed therapeutic intervention of patients, making the outcome of the disease very grim. There have been several developments in MM management, principally based on early detection, improved diagnosis, development of more effective therapies, and new insights into the pathobiology of the disease. Several programs have been used to screen asbestos-exposed individuals for lung and pleural disease. These programs involve annual pulmonary function tests, chest radiography and high resolution computer tomography. Blood tests make screening of target populations an attractive strategy. Many current gene and protein expression studies aim to identify clinically useful biomarkers and new therapeutic targets for improved management of MM.

Alpha-Tocopheryl Succinate Inhibits Autophagic Survival of Prostate Cancer Cells Induced by Vitamin K3 and Ascorbate to Trigger Cell Death

Background The redox-silent vitamin E analog α-tocopheryl succinate (α-TOS) was found to synergistically cooperate with vitamin K3 (VK3) plus ascorbic acid (AA) in the induction of cancer cell-selective apoptosis via a caspase-independent pathway. Here we investigated the molecular mechanism(s) underlying cell death induced in prostate cancer cells by α-TOS, VK3 and AA, and the potential use of targeted drug combination in the treatment of prostate cancer. Methodology/Principal Findings The generation of ROS, cellular response to oxidative stress, and autophagy were investigated in PC3 prostate cancer cells by using drugs at sub-toxic doses. We evaluated whether PARP1-mediated apoptosis-inducing factor (AIF) release plays a role in apoptosis induced by the combination of the agents. Next, the effect of the combination of α-TOS, VK3 and AA on tumor growth was examined in nude mice. VK3 plus AA induced early ROS formation associated with induction of autophagy in response to oxidative stress, which was reduced by α-TOS, preventing the formation of autophagosomes. α-TOS induced mitochondrial destabilization leading to the release of AIF. Translocation of AIF from mitochondria to the nucleus, a result of the combinatorial treatment, was mediated by PARP1 activation. The inhibition of AIF as well as of PARP1 efficiently attenuated apoptosis triggered by the drug combination. Using a mouse model of prostate cancer, the combination of α-TOS, VK3 and AA was more efficient in tumor suppression than when the drugs were given separately, without deleterious side effects. Conclusions/Significance α-TOS, a mitochondria-targeting apoptotic agent, switches at sub-apoptotic doses from autophagy-dependent survival of cancer cells to their demise by promoting the induction of apoptosis. Given the grim prognosis for cancer patients, this finding is of potential clinical relevance.