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San Fedele Superiore, Italy

Testa U.,Oncology and Molecular Medicine
Journal of Cellular Biochemistry

Defects in apoptosis are observed in many cancer cell types and contribute in a relevant way to tumorigenesis. Apoptosis is a complex and well-regulated cell death program that plays a key role in the control of cell homeostasis, particularly at the level of the hematopoietic system. Apoptosis can be initiated through two different mechanisms involving either activation of the death receptors (extrinsic pathway) or activation of a mitochondrial apoptotic process (intrinsic pathway). Among the various death receptors a peculiar role is played by TNF-related apoptosis-inducing ligand (TRAIL)-receptors (TRAIL-Rs) and their ligand TRAIL. TRAIL recently received considerable interest for its potent anti-tumor killing activity, sparing normal cells. Here, we will review the expression and the abnormalities of TRAIL/TRAIL-R system in hematologic malignancies. The large majority of primary hematologic tumors are resistant to TRAIL-mediated apoptosis, basically due to the activation of anti-apoptotic signaling pathway (such as NF-kB), overexpression of anti-apoptotic proteins (such as FLIP, Bcl-2, XIAP) or expression of TRAIL decoy receptors or reduced TRAIL-R1/-R2 expression. Strategies have been developed to bypass this TRAIL resistance and are based on the combination of TRAIL with chemotherapy or radiotherapy, or with proteasome or histone deacetylase or NF-κB inhibitors. The agents used in combination with TRAIL either enhance TRAIL-R1/-R2 expression or decrease expression of anti-apoptotic proteins (c-FLIP, XIAP, Bcl-2). Many of these combinatorial therapies hold promise for future developments in treatment of hematologic malignancies. © 2010 Wiley-Liss, Inc. Source

Zeuner A.,Oncology and Molecular Medicine
Cell Death and Differentiation

Lung cancer is the most common cause of cancer-related mortality worldwide, urging the discovery of novel molecular targets and therapeutic strategies. Stem cells have been recently isolated from non-small cell lung cancer (NSCLC), thus allowing the investigation of molecular pathways specifically active in the tumorigenic population. We have found that Bcl-XL is constantly expressed by lung cancer stem cells (LCSCs) and has a prominent role in regulating LCSC survival. Whereas chemotherapeutic agents were scarcely effective against LCSC, the small molecule Bcl-2/Bcl-XL inhibitor ABT-737, but not the selective Bcl-2 inhibitor ABT-199, induced LCSC death at nanomolar concentrations. Differently from gemcitabine, which preferentially eliminated proliferating LCSC, ABT-737 had an increased cytotoxic activity in vitro towards quiescent/slow-proliferating LCSC, which expressed high levels of Bcl-XL. In vivo, ABT-737 as a single agent was able to inhibit the growth of LCSC-derived xenografts and to reduce cancer stem cell content in treated tumors. Altogether, these results indicate that quiescent/slow-proliferating LCSC strongly depend on Bcl-XL for their survival and indicate Bcl-XL inhibition as a potential therapeutic avenue in NSCLC.Cell Death and Differentiation advance online publication, 18 July 2014; doi:10.1038/cdd.2014.105. Source

Bonci D.,Oncology and Molecular Medicine
Recent Patents on Cardiovascular Drug Discovery

MicroRNAs (miRNAs) are a broad class of small non-coding RNAs that control expression of complementary target messenger RNAs. Dysregulation of miRNAs has been described in various disease states including cancer and cardiac disease. A particular miRNA that was consistently reported to be upregulated in both cancer and various forms of cardiovascular diseases is miR-21. MiR-21 exerts oncogenic activity and therefore is considered as an oncomir. In the cardiovascular system miR-21 is enriched in fibroblasts and contributes to the development of fibrosis and heart failure. MiR-21 therefore emerges as an interesting candidate for the development of therapeutic strategies against many forms of cancer as well as heart diseases. Indeed, treatment with anti-miR-21 oligonucleotides reduced breast cancer growth. Inhibition of miR-21 by synthetic miRNA antagonists (antagomirs) improved heart function in a cardiac disease model. The same beneficial effects were observed in miR-21 knockout mice subjected to pressure-overload of the left ventricle underlining the key role of miR-21 as a therapeutic target. We here overview the current patent situation about the therapeutic use of miR-21 modulation in cancer and cardiovascular disease. © 2010 Bentham Science Publishers Ltd. Source

Among strategies aimed at developing new nanoparticle-based vaccines, exosomes hold much promise. They are nanovesicles released by basically all eukaryotic cell types originating from intraluminal vesicles which accumulate in multivesicular bodies. Exosomes have immunogenic properties whose strength correlates with the amounts of associated antigens. Engineering antigens to target them in exosomes represents the last frontier in terms of nanoparticle-based vaccines. Here we report a new method to incorporate protein antigens in exosomes relying on the unique properties of a mutant of the HIV-1 Nef protein, Nefmut. This is a biologically inactive mutant we found incorporating into exosomes at high levels also when fused at its C-terminus with foreign proteins. We compared both biochemical and antigenic properties of Nefmut exosomes with those of previously characterized Nefmut -based lentiviral virus-like particles (VLPs). We found that exosomes incorporate Nefmut and fusion protein derivatives with similar efficiency of VLPs. When an envelope fusion protein was associated with both exosomes and VLPs to favor cross-presentation of associated antigens, Nefmut and its derivatives incorporated in exosomes were cross-presented at levels at least similar to what observed when the antigens were delivered by engineered VLPs. This occurred despite exosomes entered target cells with an apparent lower efficiency than VLPs. The unique properties of HIV-1 Nefmut in terms of exosome incorporation efficiency, carrier of foreign antigens, and lack of anti-cellular effects open the way toward the development of a flexible, safe, cost-effective exosome-based CD8+ T cell vaccine platform. © 2012 Elsevier Ltd. Source

Testa U.,Oncology and Molecular Medicine
Annals of Hematology

Leukemia-initiating cells (LICs) or leukemia stem cells (LSCs) are defined by their ability to form tumors after xenotransplantation in immunodeficient mice and appear to be rare in most human leukemias. In various leukemias, only small subpopulations of cells can transfer disease upon transplantation into immunocompromised NOD/SCID mice, and markers that distinguish the leukemogenic cancer cells from the bulk populations of non-leukemogenic cells have been identified. However, the phenotype of LICs is heterogeneous: it is variable for the different types of acute myeloid leukemias; cells with different membrane phenotype can act as LICs in each B-acute lymphoid leukemia; LICs change during the evolution of chronic myeloid leukemia from the chronic to the acute phase. There is a general consensus that the identification and characterization of leukemic stem cells might lead to the identification of new therapeutic targets and, through this way, to more effective treatments by focusing therapy on the most malignant cells. © Springer-Verlag 2010. Source

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