Redox-sensitive signaling factors as a novel molecular targets for cancer therapy.

Tumor cells undergoing proliferation, de-differentiation and progression depend on a complex set of respiratory pathways to generate the necessary energy. The metabolites from these pathways produce significant oxidative stress and must be buffered to prevent permanent cell damage and cell death. It is now clear that, in order to cope with and defend against the detrimental effects of oxidative stress, a series of redox-sensitive, pro-survival signaling pathways and factors regulate a complex intracellular redox buffering network. This review develops the hypothesis that tumor cells use these redox-sensitive, pro-survival signaling pathways and factors - up-regulated due to increased tumor cell respiration - to evade the damaging and cytotoxic effects of specific anticancer agents. It further suggests that redox-sensitive, signaling factors may be potential novel targets for drug discovery.     

p14ARF protein expression is a predictor of both relapse and survival in squamous cell carcinoma of the anterior tongue.

PURPOSE: The INK4A-ARF locus at chromosome 9p21 is frequently altered in head and neck squamous cell carcinoma (SCC) and encodes two distinct tumor suppressors, p16(INK4A) and p14(ARF). This study addressed the role of p14(ARF) as a potential prognostic marker in this disease. EXPERIMENTAL DESIGN: p14(ARF) protein expression was assessed by immunohistochemistry in a cohort of 140 patients with SCC of the anterior tongue. Using univariate and multivariate Cox's proportional hazards models, the outcomes examined were time to disease recurrence or death, with or without clinicopathologic covariates, including nodal status, disease stage, treatment status, Ki-67 staining, and molecular markers with known functional or genetic relationships with p14(ARF) (p16(INK4A), p53, pRb, p21(WAF1/CIP1), E2F-1). RESULTS: On multivariate analysis, p14(ARF) positivity (nucleolar p14(ARF) staining and/or nuclear p14(ARF) staining in >/=30% of tumor cells) was an independent predictor of improved disease-free survival (DFS; P = 0.002) and overall survival (OS; P = 0.002). This was further enhanced when p14(ARF) positivity was cosegregated with positive (>/=1%) p16(INK4A) staining (DFS, P < 0.001; OS, P < 0.001). Patients whose cancers were p14(ARF) negative and p53 positive (>50%) had the poorest outcome (DFS, P < 0.001; OS, P < 0.001) of any patient subgroup analyzed. CONCLUSIONS: These data show that in patients with SCC of the tongue, combined nuclear and nucleolar expression of p14(ARF) protein predicts for improved DFS and OS independent of established prognostic markers.     

Detection of spontaneous CD4+ T-cell responses in melanoma patients against a tyrosinase-related protein-2-derived epitope identified in HLA-DRB1*0301 transgenic mice.

PURPOSE: The frequently expressed differentiation antigen tyrosinase-related protein-2 (TRP-2) has repeatedly been described as a target of spontaneous cytotoxic T-cell responses in melanoma patients, suggesting that it might be an ideal candidate antigen for T cell-based immunotherapy. As a prerequisite for immunization, T-cell epitopes have to be identified. Whereas a number of HLA class I-presented TRP-2-derived epitopes are known, information about HLA class II-presented antigenic ligands recognized by CD4+ T helper (Th) cells is limited. EXPERIMENTAL DESIGN: The search for TRP-2-derived Th epitopes was carried out by competitive in vitro peptide binding studies with predicted HLA-DRB1*0301 ligands in combination with peptide and protein immunizations of HLA-DRB1*0301 transgenic mice. In vivo selected candidate epitopes were subsequently verified for their immunogenicity in human T-cell cultures. RESULTS: This strategy led to the characterization of TRP-2(60-74) as an HLA-DRB1*0301-restricted Th epitope. Importantly, TRP-2(60-74)-reactive human CD4+ Th cell lines, specifically recognizing target cells loaded with recombinant TRP-2 protein, could be established by repeated peptide stimulation of peripheral blood lymphocytes from several HLA-DRB1*03+ melanoma patients. Even short-term peptide stimulation of patients' peripheral blood lymphocytes showed the presence of TRP-2(60-74)-reactive T cells, suggesting that these T cells were already activated in vivo. CONCLUSION: Peptide TRP-2(60-74) might be a useful tool for the improvement of immunotherapy and immune monitoring of melanoma patients.     

Les thérapies ciblées des cancers des VADS

Résumé: Nous abordons dans cette revue de la littérature les thérapies ciblées des carcinomes épidermoïdes des voies aérodigestives supérieures (CEVADS). Vu les modifications moléculaires engendrées par la carcinogenèse des CEVADS, de nouvelles stratégies thérapeutiques sont venues enrichir l’arsenal du traitement conventionnel. Ces nouvelles molécules visent les altérations moléculaires et bloquent des voies métaboliques jouant sur la progression tumorale. Le chef de file en est le récepteur à l’«epidermal growth factor».Les cancers des voies aéro-digestives supérieures     

High basal NF-κB activity in nonpigmented melanoma cells is associated with an enhanced sensitivity to vitamin D3 derivatives

Background:

Melanoma is highly resistant to current modalities of therapy, with the extent of pigmentation playing an important role in therapeutic resistance. Nuclear factor-κB (NF-κB) is constitutively activated in melanoma and can serve as a molecular target for cancer therapy and steroid/secosteroid action.

Methods:

Cultured melanoma cells were used for mechanistic studies on NF-κB activity, utilising immunofluorescence, western blotting, EMSA, ELISA, gene reporter, and estimated DNA synthesis assays. Formalin-fixed, paraffin-embedded specimens from melanoma patients were used for immunocytochemical analysis of NF-κB activity in situ.

Results:

Novel 20-hydroxyvitamin (20(OH)D₃) and classical 1α,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) secosteroids inhibited melanoma cell proliferation. Active forms of vitamin D were found to inhibit NF-κB activity in nonpigmented cells, while having no effect on pigmented cells. Treatment of nonpigmented cells with vitamin D3 derivatives inhibited NF-κB DNA binding and NF-κB-dependent reporter assays, as well as inhibited the nuclear translocation of the p65 NF-κB subunit and its accumulation in the cytoplasm. Moreover, analysis of biopsies of melanoma patients showed that nonpigmented and slightly pigmented melanomas displayed higher nuclear NF-κB p65 expression than highly pigmented melanomas.

Conclusion:

Classical 1,25(OH)₂D₃ and novel 20(OH)D₃ hydroxyderivatives of vitamin D3 can target NF-κB and regulate melanoma progression in nonpigmented melanoma cells. Melanin pigmentation is associated with the resistance of melanomas to 20(OH)D₃ and 1,25(OH)₂D₃ treatment.     

A ridge-to-reef ecosystem microbial census reveals environmental reservoirs for animal and plant microbiomes

Microbes are found in nearly every habitat and organism on the planet, where they are critical to host health, fitness, and metabolism. In most organisms, few microbes are inherited at birth; instead, acquiring microbiomes generally involves complicated interactions between the environment, hosts, and symbionts. Despite the criticality of microbiome acquisition, we know little about where hosts’ microbes reside when not in or on hosts of interest. Because microbes span a continuum ranging from generalists associating with multiple hosts and habitats to specialists with narrower host ranges, identifying potential sources of microbial diversity that can contribute to the microbiomes of unrelated hosts is a gap in our understanding of microbiome assembly. Microbial dispersal attenuates with distance, so identifying sources and sinks requires data from microbiomes that are contemporary and near enough for potential microbial transmission. Here, we characterize microbiomes across adjacent terrestrial and aquatic hosts and habitats throughout an entire watershed, showing that the most species-poor microbiomes are partial subsets of the most species-rich and that microbiomes of plants and animals are nested within those of their environments. Furthermore, we show that the host and habitat range of a microbe within a single ecosystem predicts its global distribution, a relationship with implications for global microbial assembly processes. Thus, the tendency for microbes to occupy multiple habitats and unrelated hosts enables persistent microbiomes, even when host populations are disjunct. Our whole-watershed census demonstrates how a nested distribution of microbes, following the trophic hierarchies of hosts, can shape microbial acquisition.

Microbial partners metabolize our food, fight off disease, and run the machinery that sustains the air we breathe, water we drink, and soil under our feet. Despite their importance, most host-associated microbes are generally not present at birth and are instead acquired (1). Because microbial symbionts can influence host health and fitness, the processes that determine how different microbiomes assemble within different hosts is a matter of active and urgent inquiry. Microbial ecologists have made great progress in determining how factors such as abiotic conditions (2–4), host evolution (5, 6), and microbial traits (7–9) shape environmental microbiomes, but considerably less is known about how surrounding environments or different guilds of host organisms contribute to host-associated microbiome composition. Longitudinal studies show that microbial richness accumulates and community composition changes over time across a wide diversity of hosts and habitats (1), but we know comparatively little about from where these microbes originate. To better understand microbial transmission and its role in community composition, we propose a framework that relies on theory from foodweb and landscape ecology.The concept of a foodweb has had a place in the ecological lexicon since at least the time of Elton (1927; (10)), and others such as Lindeman (11) and Odum (12) significantly expanded upon this notion to include how macroorganisms interact within their environments, in addition to their feeding relationships. The units of study for foodwebs are ecosystems, which are spatially explicit and include all organisms along with their abiotic environments and their interactions within its bounds (13). This definition was born from the efforts of the founders of the Hubbard Brook Ecosystem Study (HBES; 1963), who recognized that a watershed naturally delineates the boundaries of an ecosystem, an idea that parallels the Hawaiian ahupuaʻa concept. Since then, the HBES and its framework have led to numerous milestones in our understanding of processes such as the effects of long-term changes in acidification (14) and ecosystem impacts of global warming (15). Here, we adopt the notion of the watershed as an entire discrete ecosystem to better understand the landscape ecology of microbes. Landscape ecology is a means to understand how spatial processes affect biodiversity (16). In classic landscape ecology theory, the structure (heterogeneity) and fragmentation of habitats (or patches) within a matrix of otherwise inhospitable areas affect species’ dispersal ability and establishment. This ultimately shapes species’ abundance and distributions across the landscape (17). Contemporary landscape ecology theory extends this idea to include the concept of a landscape continuum, where continuous environmental variables, as opposed to discrete habitat patches surrounded by a matrix, better describe species’ distributions. Connecting these concepts, foodwebs are embedded in landscapes, and watersheds constitute a useful unit of measure to better understand their interactions.To expand concepts from foodweb and landscape ecology to be inclusive of microbes, we must first consider the following: a landscape for microbes can be both structural (e.g., different land covers or hydrology) and biotic (e.g., variation in the distribution of host populations). Also, microbes might better fit a continuous landscape model rather than a patch model if their distributions are not governed merely by the presence of a compatible host or habitat, but rather, if they exist among multiple hosts across a gradient of environmental conditions. This requires microbes to be generalists to some degree and/or a matrix that is at least partially hospitable (18). These considerations are important because while microbial transmission among related hosts is one obvious means of microbiome assembly, this model, in and of itself, is insufficient to sustain microbiomes (defined here as communities of bacteria and archaea) across a dynamic landscape. For example, many plants and animals are either sparse, seasonal, or ephemeral, requiring that their symbiotic microbes be capable of residing, at times, in alternate nearby hosts or environments. This potential for a microbe to persist in, and disperse among, hosts of different kingdoms and guilds, or even between liquid and land, is a trait with the potential to add an additional dimension to microbiome assembly theory (19). Where, then, might a host’s microbes reside when not inside that host? In addition, what factors might predict microbiome distributions among potentially interacting hosts and environments?Variability in matrix suitability and host specialization may result in differing microbial communities reflected in one of three nonmutually exclusive patterns, each of which leaves a diagnostic imprint on microbiome structure. If any host or environment has an equal likelihood of harboring microbes that are present in any other host or environment, we might expect host–microbe interaction networks that are randomly structured. Alternatively, if microbes are more likely to co-occur among related hosts or guilds, we might expect these to contain unique and specific consortia of microbes (modules) that are not found elsewhere in the interaction network. Finally, host–microbe interactions might be best characterized as stratified, resulting in a network topology in which microbial diversity is nested such that taxa-poor microbiomes are subsets of those that are taxa-rich. In this scenario, nonhost environmental matrices (e.g., soil, sediment, water) serve as reservoirs of broad microbial diversity that is subsequently, and hierarchically, partitioned into simpler microbiomes. While this concept is fairly intuitive, there are actually few, if any, studies that demonstrate transmission among environmental microbiomes and multiple hosts at ecosystem scales. Instead, many of the insights gleaned into assembly processes of microbiomes are owed to studies of single hosts, tractable model systems, or global syntheses (20). We address this gap by sampling microbiomes from aquatic, marine, and terrestrial foodwebs within a single watershed to examine the dynamics of sources and sinks of microbial diversity.Here, we present a microbial census of a model ecosystem metacommunity in which continental-scale environmental heterogeneity is recapitulated within a comparatively small watershed. Because of this, we can surmise the distribution limits of microbiomes across land, stream, and sea, a feat that would not be plausible in most other landscapes of similar size or environmental variability. From ridge to reef, our compact watershed spans a roughly 3.5 m rainfall differential, ∼27 times that encountered along the Mississippi, the largest watershed in continental North America. Also, our model ecosystem is located on the most isolated archipelago on the planet, making exogenous microbial inputs infrequent, if not unlikely. Furthermore, owing to parallels in environmental heterogeneity and foodweb structure across this compact watershed compared to others, our findings are potentially relevant for highly connected ecosystems that span substantially larger geographic areas.For example, a long-standing question in biogeography is the relationship between organisms’ local distributions and those at larger scales. Many factors influence the distributions of microbes, including their physiology, size, population density, and dispersal abilities (21–23). A common assumption is that niche breadth should also predict the range size of an organism, since the ability to survive in broader environments, and to use a greater array of resources, should indicate the ability to occupy more habitats that occur over greater distances (24, 25). This is an important component of source and sink dynamics, because it suggests that local occupancy should predict global distributions. This relationship is seldom tested empirically, however, because small areas rarely contain, or are sampled for, broad climatic variability and host diversity. In the absence of phenotypic, genomic, or even well-resolved taxonomic information about the majority of the earth’s microbial biodiversity, geographic range is one of the few traits that can be directly inferred from short environmental DNA sequence reads. By examining our ecosystem-wide microbiome census within the context of the global survey of the Earth Microbiome Project (26), we assess the relationship between global and local microbial distributions.     

Association of KCNJ11 and ABCC8 single-nucleotide polymorphisms with type 2 diabetes mellitus in a Kinh Vietnamese population

Type 2 diabetes mellitus (T2DM) is a genetically influenced disease, but few studies have been performed to investigate the genetic basis of T2DM in Vietnamese subjects. Thus, the potential associations of KCNJ11 and ABCC8 single nucleotide polymorphisms (SNPs) with T2DM were investigated in a Kinh Vietnamese population. A cross-sectional study consisting of 404 subjects including 202 T2DM cases and 202 non-T2DM controls was designed to examine the potential associations of 4 KCNJ11 and ABCC8 SNPs (rs5219, rs2285676, rs1799859, and rs757110) with T2DM. Genotypes were identified based on restriction fragment length polymorphism and tetra-primer amplification refractory mutation system polymerase chain reaction. After statistically adjusting for age, sex, and BMI, rs5219 was found to be associated with an increased risk of T2DM under 2 inheritance models: codominant (OR = 2.15, 95% confidence intervals [CI] = 1.09–4.22) and recessive (OR = 2.08, 95%CI = 1.09–3.94). On the other hand, rs2285676, rs1799859, and rs757110 were not associated with an increased risk of T2DM. Haplotype analysis elucidated a strong linkage disequilibrium between the 3 SNPs, rs5219, rs2285676, and rs757110. The haplotype rs5219(A)/rs2285676(T)/rs757110(G) was associated with an increased risk of T2DM (OR = 1.42, 95%CI = 1.01–1.99). The results show that rs5219 is a lead candidate SNP associated with an increased risk of developing T2DM in the Kinh Vietnamese population. Further functional characterization is needed to uncover the mechanism underlying the potential genotype-phenotype associations.