Correlative links between natural radiation and life expectancy in the US population.

The linear no-threshold (LNT) hypothesis is still the ruling concept which dictates the radiation protection health policy and regulations. However, more and more studies show that not only that low dose radiation pose no danger to our health, but also exhibits clear beneficial health effects. Here, we evaluated the correlative links of the natural sources of radiation-terrestrial radiation (TR), cosmic radiation (CR), and Radon-222, with life expectancy, the most integrative index of population health. The results of this study show that the different sources of natural radiation display positive correlative links to life expectancy, which is in line with the hypothesis of radiation hormesis.

Small molecules for cell reprogramming: a systems biology analysis.

If somatic stem cells would be able to maintain their regenerative capacity over time, this might, to a great extent, resolve rejuvenation issues. Unfortunately, the pool of somatic stem cells is limited, and they undergo cell aging with a consequent loss of functionality. During the last decade, low molecular weight compounds that are able to induce or enhance cell reprogramming have been reported. They were named "Small Molecules" (SMs) and might present definite advantages compared to the exogenous introduction of stemness-related transcription factors (e.g. Yamanaka's factors). Here, we undertook a systemic analysis of SMs and their potential gene targets. Data mining and curation lead to the identification of 92 SMs. The SM targets fall into three major functional categories: epigenetics, cell signaling, and metabolic "switchers". All these categories appear to be required in each SM cocktail to induce cell reprogramming. Remarkably, many enriched pathways of SM targets are related to aging, longevity, and age-related diseases, thus connecting them with cell reprogramming. The network analysis indicates that SM targets are highly interconnected and form protein-protein networks of a scale-free topology. The extremely high contribution of hubs to network connectivity suggests that (i) cell reprogramming may require SM targets to act cooperatively, and (ii) their network organization might ensure robustness by resistance to random failures. All in all, further investigation of SMs and their relationship with longevity regulators will be helpful for developing optimal SM cocktails for cell reprogramming with a perspective for rejuvenation and life span extension.

Background radiation impacts human longevity and cancer mortality: reconsidering the linear no-threshold paradigm.

The current linear no-threshold paradigm assumes that any exposure to ionizing radiation carries some risk, thus every effort should be made to maintain the exposures as low as possible. We examined whether background radiation impacts human longevity and cancer mortality. Our data covered the entire US population of the 3139 US counties, encompassing over 320 million people. This is the first large-scale study which takes into account the two major sources of background radiation (terrestrial radiation and cosmic radiation), covering the entire US population. Here, we show that life expectancy, the most integrative index of population health, was approximately 2.5 years longer in people living in areas with a relatively high vs. low background radiation. (≥ 180 mrem/year and ≤ 100 mrem/year, respectively; p < 0.005; 95% confidence interval [CI]). This radiation-induced lifespan extension could to a great extent be associated with the decrease in cancer mortality rate observed for several common cancers (lung, pancreas and colon cancers for both genders, and brain and bladder cancers for males only; p < 0.05; 95% CI). Exposure to a high background radiation displays clear beneficial health effects in humans. These hormetic effects provide clear indications for re-considering the linear no-threshold paradigm, at least within the natural range of low-dose radiation.

c-Met as a new marker of cellular senescence.

Here, we reported for the first time an increased expression of c-Met protein in primary cultures of human dermal and pulmonary fibroblasts of late passages. This suggests that c-Met could serve as an early marker of cellular senescence (CS). The levels of c-Met-related signaling proteins phospho-Akt and Stat3 were also increased in (pre)senescent fibroblasts. Considering the anti-apoptotic activity of Akt and the involvement of Stat3 in mediating the effects of proinflammatory cytokines, the findings of this study indicate that c-Met could contribute through its downstream targets or partners to at least two major phenotypical features of CS - resistance to apoptosis and senescence-associated secretory phenotype.

Transplantation of mesenchymal stem cells reverses behavioural deficits and impaired neurogenesis caused by prenatal exposure to valproic acid.

Neurodevelopmental impairment can affect lifelong brain functions such as cognitive and social behaviour, and may contribute to aging-related changes of these functions. In the present study, we hypothesized that bone marrow-derived mesenchymal stem cells (MSC) administration may repair neurodevelopmental behavioural deficits by modulating adult hippocampal neurogenesis. Indeed, postnatal intracerebral transplantation of MSC has restored cognitive and social behaviour in mice prenatally exposed to valproic acid (VPA). MSC transplantation also restored post-developmental hippocampal neurogenesis, which was impaired in VPA-exposed mice displaying delayed differentiation and maturation of newly formed neurons in the granular cell layer of the dentate gyrus. Importantly, a statistically significant correlation was found between neuronal differentiation scores and behavioural scores, suggesting a mechanistic relation between the two. We thus conclude that post-developmental MSC administration can overcome prenatal neurodevelopmental deficits and restore cognitive and social behaviours via modulation of hippocampal adult neurogenesis.

Cellular Senescence Markers p16INK4a and p21CIP1/WAF Are Predictors of Hodgkin Lymphoma Outcome.

PURPOSE: There is evidence that Hodgkin Reed-Sternberg (HRS) cells in classical Hodgkin lymphoma (cHL) could display some molecular and morphologic markers of cellular senescence (CS). We hypothesized that CS mechanisms may have potential prognostic relevance in cHL and investigated whether the expression of the well-established CS biomarkers p21(CIP1/WAF1) and p16(INK4a) by HRS cells might be predictive of the probability of event-free survival (EFS). EXPERIMENTAL DESIGN: The study analyzed a retrospective cohort of 147 patients and the results were validated on a cohort of 91 patients independently diagnosed and treated in a different institution. p16(INK4a) and p21(CIP1/WAF1) were categorized as dichotomous variables (< or ≥ 30% of HRS cells at diagnosis) and evaluated in univariate and multivariate analysis. RESULTS: Both molecules were independent prognostic factors. A positive staining of one of the two molecules in more than 30% HRS cells predicted a better EFS (P < 0.01). p16(INK4a)/p21(CIP1/WAF1) together as a unique categorical variable (both <30%, either <30%, both ≥ 30%) sorted out three prognostic groups with better, intermediate, or worse outcome either overall or within I-II, bulky and advanced stages. The presence or the lack of the robust expression of p21(CIP1/WAF1) and/or p16(INK4a) defined the prognosis in our series. CONCLUSIONS: These findings point to (i) the relevance of CS-related mechanisms in cHL, and to (ii) the prognostic value of a simple, reproducible, and low-cost immunohistochemical evaluation of p16(INK4a) and p21(CIP1/WAF1) expression.

ShcC proteins: brain aging and beyond.

To date, most studies of Shc family of signaling adaptor proteins have been focused on the near-ubiquitously expressed ShcA, indicating its relevance to age-related diseases and longevity. Although the role of the neuronal ShcC protein is much less investigated, accumulated evidence suggests its importance for neuroprotection against such aging-associated conditions as brain ischemia and oxidative stress. Here, we summarize more than decade of studies on the ShcC expression and function in normal brain, age-related brain pathologies and immune disorders with a focus on the interactions of ShcC with signaling proteins/pathways, and the possible implications of these interactions for changes associated with aging.

Uncovering the geroprotective potential of medicinal plants from the Judea region of Israel.

Plants growing in the Judea region are widely used in traditional medicine. This phytogeographic zone stands out in its climatic conditions and biodiversity. Consequently, both endemic and widely distributed Mediterranean plants growing in the area have unique chemotypes characterized by accumulation of relatively high levels of phytosteroids. Our comprehensive analysis revealed that many of the plants growing in the Judea region may hold a geroprotective potential. With this in mind, we undertook a wide screen of dozens of candidate herbal extracts for their cell protective, wound-healing, anti-inflammatory, and anti-cancer activities. The results obtained thus far have clearly shown that the extracts tested (1) protect normal human fibroblasts from genotoxic stress (prevent DNA double-strand beaks, increase cell survival and reduce the number of cells undergoing cellular senescence), (2) decrease secretion of pro-inflammatory cytokines, (3) promote wound healing, and (4) exert more pronounced cytotoxicity toward cancer cells.

Chronic treatment with anti-bipolar drugs causes intracellular alkalinization in astrocytes, altering their functions.

Bipolar disorder I and II are affective disorders with mood changes between depressive and manic (bipolar I) or hypomanic (bipolar II) periods. Current therapy of these conditions is chronic treatment with one or more of the anti-bipolar drugs, Li(+) ('lithium'), carbamazepine and valproic acid. The pathophysiology of bipolar disorder is multifactorial and far from clear. Recent data on the dependence of normal brain function on neuronal-astrocytic interactions raise the possibility of astrocytic involvement. We will discuss our previously published and new results on effects of chronic treatment of primary cultures of normal mouse astrocytes with any of three conventional anti-bipolar drugs. The focus will be on several drug-induced events in relation to therapeutic effects of the drugs, such as myo-inositol uptake, intracellular pH and alkalinization, drug-induced modulation of glutamatergic activity in astrocytes and release of astrocytic 'gliotransmitters'. Finally, we will discuss the importance of phospholipase A2 (PLA(2)) and arachidonic acid cascade in drug-treated astrocytes, partly based on Dr. Barneda Cuirana's published thesis. All three drugs cause gradual intracellular alkalinization through different mechanisms. Alkalinization inhibit myo-inositol uptake, resulting in reduced inositolphosphate/phospholipid signaling. Accordingly, transmitter-induced increase in free intracellular Ca(2+) ([Ca(2+)](i)) becomes inhibited, aborting release of astrocytic 'gliotransmitters'. The reduction of "gliotransmitter" effects on neurons may have therapeutic effects in mania. Alkalinization also up-regulates expression of cPLA(2), an enzyme releasing arachidonic acid, and triggered arachidonic acid cascade and production, but perhaps not release, of prostaglandins. Whenever tested, identical effects were observed in freshly isolated astrocytes, but not neurons, from carbamazepine-treated healthy animals.

Enhanced genetic instability and dasatinib sensitivity in mammary tumor cells lacking NEDD9.

Elevated expression of the NEDD9/HEF1/Cas-L scaffolding protein promotes tumor cell invasion and metastasis in multiple cancer cell types. Conversely, generation of mammary tumors in the mouse mammary tumor virus (MMTV)-polyoma virus middle T (PyVT) genetic model is delayed by a Nedd9(-/-) genotype. These activities arise from the role of NEDD9 in assembling complexes and supporting activity of cancer signaling proteins, including FAK, Src, Shc, and AKT, and would support evaluation of NEDD9 expression as an unambiguous biomarker for tumor aggressiveness. However, we here show that despite the initial delay in tumor growth, cells derived from MMTV-PyVT;Nedd9(-/-) tumors are characteristically hyperaggressive versus MMTV-PyVT;Nedd9(+/+) cells in anchorage-independent growth, in growth on three-dimensional matrix produced by tumor-associated fibroblasts, and in formation of tumors after mammary orthotopic reinjection and of lung metastases after tail vein injection. This reversal suggests the specific selection of MMTV-PyVT;Nedd9(-/-) cells for growth in an in vivo microenvironment. Indeed, MMTV-PyVT;Nedd9(-/-) cells have increased cell cycle, centrosomal, and mitotic defects, phenotypes compatible with the increased selection of these cells for aggressive growth. Intriguingly, in spite of their aggressive phenotype, MMTV-PyVT;Nedd9(-/-) cells persistently have low levels of Src activation and are hypersensitive to the Src kinase inhibitor dasatinib. These studies identify NEDD9 as a complex modulator of different aspects of mammary tumor growth.

MicroRNA-regulated protein-protein interaction networks: how could they help in searching for pro-longevity targets?

In spite of enormous efforts and accumulated knowledge, our capabilities for tackling aging and age-related diseases (ARDs), and ultimately to promote longevity, are still very modest. What is lacking--essential data on key players, efficient analytic tools, or both? Here we discuss how the existing data may be integrated and analyzed in the context of microRNA (miRNA)-regulated protein-protein interaction networks. The proposed model highlighted: (1) The strong molecular links between aging, longevity, and ARDs; (2) the possibility and even the preferability of initiating longevity-promoting interventions in adult life; (3) the potentially important role for miRNA- (or small interfering RNA [siRNA]) mediated targeting of certain genes with features of antagonistic pleiotropy; (4) the superiority of systemic interventions to the common single-target approach in curing ARDs and promoting longevity.

NEDD9 promotes oncogenic signaling in mammary tumor development.

In the past 3 years, altered expression of the HEF1/CAS-L/NEDD9 scaffolding protein has emerged as contributing to cancer metastasis in multiple cancer types. However, whereas some studies have identified elevated NEDD9 expression as prometastatic, other work has suggested a negative role in tumor progression. We here show that the Nedd9-null genetic background significantly limits mammary tumor initiation in the MMTV-polyoma virus middle T genetic model. Action of NEDD9 is tumor cell intrinsic, with immune cell infiltration, stroma, and angiogenesis unaffected. The majority of the late-appearing mammary tumors of MMTV-polyoma virus middle T;Nedd9(-/-) mice are characterized by depressed activation of proteins including AKT, Src, FAK, and extracellular signal-regulated kinase, emphasizing an important role of NEDD9 as a scaffolding protein for these prooncogenic proteins. Analysis of cells derived from primary Nedd9(+/+) and Nedd9(-/-) tumors showed persistently reduced FAK activation, attachment, and migration, consistent with a role for NEDD9 activation of FAK in promoting tumor aggressiveness. This study provides the first in vivo evidence of a role for NEDD9 in breast cancer progression and suggests that NEDD9 expression may provide a biomarker for tumor aggressiveness.

The signaling hubs at the crossroad of longevity and age-related disease networks.

The established human age-related disease proteins (ARDPs) and longevity-associated proteins (LAPs) together with their first-order interacting partners form scale-free networks which significantly overlap. About half of the common proteins are involved in signal transduction. These proteins are strongly interconnected and in turn form a common signaling network which comprises over 40% of all hubs (proteins with multiple interactions) in the human interactome. Along with the insulin pathway, the common signaling network is remarkably enriched with the focal adhesion and adherens junction proteins whose relation to the control of lifespan is yet to be fully addressed. The examples of such candidate proteins include several hubs, focal adhesion kinase PTK2 and the extracellular proteins fibronectin FN1, paxillin PXN, and vinculin VCL. The results of the network-based analysis highlight the potential importance of these pathways, especially hubs, in linking the human longevity and age-related diseases.

Common gene signature of cancer and longevity.

An association between aging/longevity and cancer has long been suggested, yet the evolutionary and molecular links between these complicated traits remain elusive. Here, we analyze the relationship between longevity- and cancer-associated genes/proteins (LAGs/LAPs and CAGs/CAPs, respectively). Specifically, we address the following questions: (1) to what extent the CAGs and LAGs are evolutionary conserved and how they (or their orthologs) are related to each other in diverse species? (2) Could they act in cooperative manner at a protein level via protein-protein interactions (PPIs) and, if so, by forming a PPI network? We found that (i) the common genes (both LAGs and CAGs) show the same remarkable trend from yeast to humans: tumor suppressors are associated with lifespan extension, whereas the oncogenes are associated with reduced lifespan; (ii) LAPs and CAPs have a significantly higher average connectivity than other proteins in the human interactome; and (iii) LAPs and CAPs may act in cooperative manner via numerous direct and indirect PPIs between themselves and eventually by forming a PPI network. Altogether, the results of this study provide strong evidence for the existence of evolutionary and molecular links between longevity and cancer.

Senescing cells share common features with dedifferentiating cells.

Dedifferentiation signifies the capacity of somatic cells to acquire stem cell-like properties. This process can be induced during normal development and as a response to various stimuli, such as pathogen infection and wounding. Dedifferentiation also characterizes the transition of differentiated leaf cells into protoplasts (plant cells devoid of cell walls), a transition accompanied by widespread chromatin decondensation. Transcriptome profiling of dedifferentiating protoplast cells revealed striking similarities with senescing cells; both display a large increase in the expression of genes of specific transcription factor (TF) families, including ANAC, WRKY, bZIP, and C2H2. Further analysis showed that leaves induced to senesce by exposure to dark display characteristic features of dedifferentiating cells, including chromatin decondensation, disruption of the nucleolus, and condensation of rRNA genes. Considering that premature senescence can be induced by various stress conditions both in plant and animal cells, our results suggest that the response of plant and also animal cells to certain stresses converges on cellular dedifferentiation whereby cells first acquire stem cell-like state prior to acquisition of a new cell fate (e.g., reentry into the cell cycle or death).

Modified pectin-based carrier for gene delivery: cellular barriers in gene delivery course.

The use of polysaccharides as DNA carriers has high potential for gene therapy applications. Pectin is a structural plant polysaccharide heterogeneous with respect to its chemical structure. It contains branches rich in galactose residues which serve as potential ligands for membrane receptors interaction. In order to make the anionic pectin applicable for DNA complexation, it was modified with three different amine groups (cationic). Pectin-NH2 was prepared by modifying the galacturonic acids carboxyl groups with primary amine groups and further modified to generate pectin-T (T=N+H(CH3)(2)) and pectin-NH2-Q (Q=N+(CH3)(3)). All three modified pectins formed complexes with plasmid DNA as indicated by gel electrophoresis analysis. The size and morphology of pectin-NH2/DNA complexes were examined by transmission electron microscopy (TEM). Transfection experiments were carried out with human embryonic kidney cell lines (HEK293), using plasmid DNA encoding for green fluorescence protein (GFP). Transfection efficiency was analyzed by flow cytometry analysis, using FACS. Pectin-NH2-Q was the most efficient carrier. Addition of chloroquine ("lysosomotropic" agent) to transfection medium substantially enhanced the HEK293 transfection, indicating that endocytosis is the preferable internalization pathway and implies on the complex inability to escape the endosome. Pectin's galactose residues contribution to transfection was examined by inhibiting pectin binding to membrane receptors (galectins), using galactose and lactose as competitive inhibitors to this interaction. Resulting reduction of transfection efficiency demonstrated the importance of pectin's galactose residues to HEK293 transfection. Suggesting the modified pectin is a promising non-viral carrier for targeted gene delivery to cancer cells with galactose-binding lectins on their surface.

[Cadherins in malignancies of the female genital tract].

Cadherins are a superfamily of adhesion molecules that mediate Ca++ -dependent cell-cell adhesion necessary for normal morphogenesis and maintenance of tissue integrity. A classical cadherin molecule, such as E-cadherin, is a glycoprotein made up of three parts: an extracellular portion composed of five identical domains, a transmembrane portion composed of a single domain and a cytoplasmic portion composed of two domains. The cytoplasmic portion is anchored by means of cytoplasmic catenins to the cytoskeleton. The three amino acids sequence, histidine, alanine and valine (HAV motif) located at the most external domain of the extracellular portion, plays a key role in homophilic recognition between two cadherin molecules and cell-cell adhesion. Loss of cell-cell adhesion may be a prerequisite for malignant transformation and the invasive behavior of malignant tumors. Research of cadherin in malignancies has attracted much attention since cadherins may be proven to be reliable markers of biological behavior and prognosis The studies on cadherin in malignancies of the female genital tract have shown the following results: 1) in malignant transformation of the ovarian surface epithelium (OSE) and in epithelial ovarian carcinoma confined to the ovary (Stage I) there is a switch from N-cadherin expression to E-cadherin expression; 2) In advanced-stage epithelial ovarian carcinoma (Stages II-IV) the results are at odds: some investigators have shown a loss of E-cadherin expression most often because of hypermethylation of the promoter region of the gene, while others have demonstrated an increase in E-cadherin expression; 3) In endometrial carcinoma, E-cadherin expression is decreasing and P-cadherin expression is increasing with worsening of histologic type and differentiation, increased penetration into the myometrium, spread beyond the uterus and involvement of pelvic lymph nodes; 4) In squamous cell carcinoma of the uterine cervix E-cadherin expression is decreasing with tumor progression and in adenocarcinoma of the uterine cervix P-cadherin expression is increasing with tumor progression. It is hoped that the development of drugs that amend cell-cell adhesion will improve the prognosis of patients in whom tumor progression is associated with decrease or loss of cadherin expression.

p66ShcA and ageing: modulation by longevity-promoting agent aurintricarboxylic acid.

Many mutations that extend the lifespan of the lower organisms such as C. elegans and Drosophila, are associated with signaling or apoptotic pathways. Recently, such a possibility was shown in mammals: p66ShcA-deficient mice were more resistant to oxidative stress and lived longer than the wild-type animals [Migliaccio, E., Giorgio, M., Mele, S., Pelicci, G., Reboldi, P., Randolfi, P.P., Lanfrancone, L., Pelicci, P.G., 1999. The p66Shc adaptor protein controls oxidative stress response and life span in mammals. Nature 402, 309-313]. There is evidence to implicate p66ShcA in age-related degenerative pathology, including atherosclerosis, sarcopenia, and Alzheimer's disease. We hypothesized that a low level expression of p66ShcA could be associated with longevity. Also, we suggested that the level of p66ShcA could be modulated by a putative longevity-promoting agent aurintricarboxylic acid [aurintricarboxylic acid (ATA); Fraifeld, V., Wolfson, M., Sagi, O., Seidman, R., Asraf, H., Utko, N., Muradian, K., 2002. Effects of anti-apoptotic agent aurintricarboxylic acid on longevity and longevity-associated processes. Biogerontology 3, 48]. We have found that: (i) the level of p66ShcA decreases with advanced age. Thirty-six-month-old mice have the lowest, whereas newborns have the highest p66ShcA levels; (ii) ATA significantly decreases the p66ShcA level in mouse lungs. In addition, the lifespan-prolongation effect of ATA in a Drosophila model was further validated. The results support the suggested role for the p66ShcA as one of the lifespan determinants in mammals; p66ShcA therefore represents a potential target for pharmacological longevity-promoting intervention.