From Oxidative Stress Damage to Pathways, Networks, and Autophagy via MicroRNAs.

Oxidative stress can alter the expression level of many microRNAs (miRNAs), but how these changes are integrated and related to oxidative stress responses is poorly understood. In this article, we addressed this question by using in silico tools. We reviewed the literature for miRNAs whose expression is altered upon oxidative stress damage and used them in combination with various databases and software to predict common gene targets of oxidative stress-modulated miRNAs and affected pathways. Furthermore, we identified miRNAs that simultaneously target the predicted oxidative stress-modulated miRNA gene targets. This generated a list of novel candidate miRNAs potentially involved in oxidative stress responses. By literature search and grouping of pathways and cellular responses, we could classify these candidate miRNAs and their targets into a larger scheme related to oxidative stress responses. To further exemplify the potential of our approach in free radical research, we used our explorative tools in combination with ingenuity pathway analysis to successfully identify new candidate miRNAs involved in the ubiquitination process, a master regulator of cellular responses to oxidative stress and proteostasis. Lastly, we demonstrate that our approach may also be useful to identify novel candidate connections between oxidative stress-related miRNAs and autophagy. In summary, our results indicate novel and important aspects with regard to the integrated biological roles of oxidative stress-modulated miRNAs and demonstrate how this type of in silico approach can be useful as a starting point to generate hypotheses and guide further research on the interrelation between miRNA-based gene regulation, oxidative stress signaling pathways, and autophagy

FUS MUTATIONS IN SPORADIC AMYOTROPHIC LATERAL SCLEROSIS: CLINICAL AND GENETIC ANALYSIS

Fused in sarcoma (FUS) or translocation in liposarcoma (TLS), a DNA/RNA-binding protein, causes a dominant autosomal inherited form of amyotrophic lateral sclerosis (ALS), ALS 6. Its main role in neurodegeneration is highlighted by the presence of cytoplasmic accumulation of its mutant protein form in ALS patients. To further define the frequency and spectrum of FUS gene mutations, we have performed a molecular screening of a cohort of 327 Italian patients from Southern Italy with sporadic ALS (SALS). We identified 4 patients carrying 3 different missense mutations and several polymorphisms. Two different substitutions occurring in the same amino acidic position have been observed in 2 patients: R521G and R521C respectively; P525L mutation has been found in 2 additional cases. Most of the patients with FUS mutations showed early symptom onset and had short disease survival. We also detected 4 different polymorphic variants (3=-untranslated region [UTR] variant, c.*41G.A; c.52313ins[GAGGTG]; c.335-15del[TTTT]; and rs13331793) in 9 patients from within our cohort. This study underlines the importance of population-based mutation screening of newly identified genes. \ua9 2011 Elsevier Inc. All rights reserved

Gene profiling for the prediction of Tumor Response to treatment:The case of Immunotherapy\u201d

Cancer is a heterogeneous disease in most respects, including its cellularity, different genetic alterations and diverse clinical behaviors. The combinatorial origin, the heterogeneity of malignant cells, and the variable host background produce multiple tumor subclasses. Many analytical methods have been used to study human tumors and to classify them into homogeneous groups that can predict clinical behavior. Currently, cancer classifications are principally based on clinical and histomorphologic features that only partially reflect this heterogeneity, reducing the probability of the most appropriate diagnostic, prognostic and therapeutic strategy for each patient. Furthermore, virtually all current anticancer agents do not differentiate between cancerous and normal cells, resulting in sometimes disastrous toxicity and an inconstant efficacy. The development of innovative drugs that selectively target cancer cells while sparing normal tissues is very promising and underscores the importance of dissecting the cascade of molecular events that underlie cancer development, progression and sensitivity to antineoplastic agents. Since these phenomena are sustained by the derangement of multiple genes, biotechnological tools allowing the simultaneous study of hundreds or thousands of molecular targets are greatly welcome and provide investigators with a unique opportunity to decipher the many enigmas that surround cell physiology and disease. Over the last decade\u2013 prompted also by the sequencing of the human genome\u2013investigators have devised several gene expression profiling methods, such as comparative genomic hybridization (CGH), differential display, serial analysis of gene expression (SAGE), and DNA arrays. The availability of such large amounts of information has shifted the attention of scientists towards a non-reductionist approach to biological phenomena. High throughput technologies can be used to follow changing patterns of gene expression over time. Among them, DNA arrays have become prominent because they are easier to use, do not require large-scale DNA sequencing, and allow the parallel quantification of thousands of genes from multiple samples. Hopefully, by integrating this powerful analytic tool with other high throughput techniques, such as tissue microarray and proteomics, investigators will be able to comprehensively describe the molecular portrait of the biological phenomena underlying tumor pathogenesis, aggressiveness and response to therapy. DNA array technology is rapidly spreading worldwide and has the potential to drastically change the therapeutic approach to patients affected with tumor: accordingly, it is of paramount importance for both researchers and clinicians to know the principles underlying this laboratory tool in order to critically appreciate the results originating from this biotechnology. In the present book, we describe the main features of microarray technology\u2013 from DNA array construction to data analysis\u2013and discuss its key applications by reviewing some of the most interesting results already achieved in the field of oncology

Functional heterogeneity of vaccine-induced CD8+ T cell subset

The functional status of circulating vaccine-induced, tumor-specific T cells has been questioned to explain their paradoxical inability to inhibit tumor growth. We enumerated with HLA-A*0201/peptide tetramers (tHLA) vaccine-elicited CD8(+) T cell precursor frequency among PBMC in 13 patients with melanoma undergoing vaccination with the HLA-A*0201-associated gp100:209-217(210 M) epitope. T cell precursor frequency increased from undetectable to 12,400 +/- 3,600 x 10(6) CD8(+) T cells after vaccination and appeared heterogeneous according to previously described functional subtypes: CD45RA(+)CD27(+) (14 +/- 2.6% of tHLA-staining T cells), naive; CD45RA(-)CD27(+) (14 +/- 3.2%), memory; CD45RA(+)CD27(-) (43 +/- 6%), effector; and CD45RA(-)CD27(-) (30 +/- 4.1%), memory/effector. The majority of tHLA(+)CD8(+) T cells displayed an effector, CD27(-) phenotype (73%). However, few expressed perforin (17%). Epitope-specific in vitro stimulation (IVS) followed by 10-day expansion in IL-2 reversed this phenotype by increasing the number of perforin(+) (84 +/- 3.6%; by paired t test, p < 0.001) and CD27(+) (from 28 to 67%; by paired t test, p = 0.01) tHLA(+) T cells. This conversion probably represented a change in the functional status of tHLA(+) T cells rather than a preferential expansion of a CD27(+) (naive and/or memory) PBMC, because it was reproduced after IVS of a T cell clone bearing a classic effector phenotype (CD45RA(+)CD27(-)). These findings suggest that circulating vaccine-elicited T cells are not as functionally active as inferred by characterization of IVS-induced CTL. In addition, CD45RA/CD27 expression may be more informative about the status of activation of circulating T cells than their status of differentiation

Gene profiling for the prediction of tumor response to treatment: the case of immunotherapy

Although anticancer immune responses can occur, the biological mechanisms responsible for them remain largely unexplained. Immunologists have extensively studied specific interactions between immune and cancer cells and have identified cofactors that may modulate the effectiveness of such interactions. In particular, as a result of the increasing molecular understanding of the basis for tumor/host interactions, their complexity has become manifest, leading to the conclusion that no single mechanism can model in humans the phenomenon of tumor rejection. It is likely that, due to human and disease heterogeneity, distinct trails lead to a final common pathway responsible for immune-mediated tumor regression. The synergy of the innate and adaptive immune response is likely to be required for successful tumor rejection. These two systems may act by enhancing and remodeling each of the functions by being recruited and activated at the tumor site by molecules with immune modulatory properties produced in the tumor micro-environment by cancer or tumor-associated normal cells. Such complexity could only be recently appreciated in its extent by high-throughput tools capable of providing a global view of biological processes as they occur. In this chapter, we will present selected examples of high-throughput gene expression profiling that may contribute to the understanding of anticancer immune responses

Adenovirus as a new agent for multiple myeloma therapies: Opportunities and restrictions.

Multiple myeloma is a malignancy of B-cells that is characterized by the clonal expansion and accumulation of malignant plasma cells in the bone marrow. This disease remains incurable, and a median survival of 3-5 years has been reported with the use of current treatments. Viral-based therapies offer promising alternatives or possible integration with current therapeutic regimens. Among several gene therapy vectors and oncolytic agents, adenovirus has emerged as a promising agent, and it is already being used for the treatment of solid tumors in humans. The main concern with the clinical use of this vector has been its high immunogenicity; adenovirus is often able to induce a strong immune response in the host. Furthermore, new limitations in the efficacy of this therapy, intrinsic to the nature of tumor cells, have been recently observed. For example, our group showed a strong antiviral phenotype in vitro and in vivo in a subset of tumors, shedding new insights that may explain the partial failure of clinical trials based on this promising new therapy. In this review, we describe novel therapeutic approaches that implement viral-based treatments in hematological malignancies and address the novelty as well as the possible limitations of these new therapies, especially in the context of the use of adenoviral vectors for treating multiple myeloma