Epigenetic changes and nuclear factor-\u3baB activation, but not microRNA-224, downregulate Raf-1 kinase inhibitor protein in triple\u2011negative breast cancer SUM 159 cells

Raf-1 kinase inhibitor protein (RKIP) is a tumor suppressor and metastasis inhibitor, which enhances drug\u2011induced apoptosis of cancer cells. Downregulation of RKIP may be significant in the biology of highly aggressive and drug\u2011resistant tumors, for example triple\u2011negative breast cancers (TNBCs). Potential causes for the low levels of RKIP expressed by SUM 159 TNBC cells were investigated in the present study. Bisulphite modification, methylation specific\u2011polymerase chain reaction (PCR) and a TransAM NF-\u3baB assay were performed and the results suggested that various mechanisms, including methylation of the gene promoter, histone deacetylation and nuclear factor\u2011\u3baB (NF\u2011\u3baB) activation, but not targeting by microRNA\u2011224 (miR/miRNA\u2011224), as determined by transfection of pre\u2011miR\u2011224 miRNA precursor or anti\u2011miR\u2011224 miRNA inhibitor, may downregulate RKIP in these cells. Furthermore, reverse transcription\u2011quantitative PCR, western blotting,3\u2011(4,5\u2011dimethylthiazol\u20112\u2011yl)\u20115\u2011(3\u2011carboxymethoxyphenyl)\u20112\u2011(4\u2011sulphophenyl)\u20112H\u2011tetrazolium cell growth assay and flow cytometry revealed that in SUM 159 cells, the demethylating agent 5\u2011aza\u20112'\u2011deoxycytidine (5\u2011AZA), the histone deacetylase inhibitor trichostatin A (TSA) and the NF\u2011\u3baB inhibitor dehydroxymethylepoxyquinomicin (DHMEQ) enhanced RKIP expression and resulted in significant cell growth inhibition and induction of apoptosis. 5\u2011AZA and TSA mainly produced additive antitumor effects, while the combination of DHMEQ and TSA exhibited significant synergy in cell growth inhibition and induction of apoptosis assays. Increasing evidence that aberrant activation of NF\u2011\u3baB signaling is a frequent characteristic of TNBC highlights the fact that this transcription factor may be a useful target for treatment of such tumors. In addition to DHMEQ, proteasome inhibitors may also represent valuable therapeutic resources in this context. Notably, proteasome inhibitors, in addition to the inhibition of NF\u2011\u3baB activation, may also restore RKIP levels by inhibiting proteasome degradation of the ubiquitinated protein. The current results contribute to the understanding of the molecular mechanisms of RKIP downregulation in TNBC and suggest possible novel therapeutic approaches for the treatment of these types of cancer

Preclinical models in oncological pharmacology: limits and advantages

A wide range of experimental tumor models, each with distinct advantages and disadvantages, is nowadays available. Due to the inherent differences in their complexity and functionality, the choice of the model is usually dependent on the application. Thus, to advance specific knowledge, one has to choose and use appropriate models, which complexity is largely dependent on the hypotheses to test, that is on the objectives. Whatever the model chosen, the complexity of cancer is such that none of them will be able to fully represent it. In vitro tumor models have provided important tools for cancer research and still serve as low-cost screening platforms for drugs. The improved understanding of cancer as "organ system" has pushed for increased accuracy and physiological relevance of in vitro tumor models that have in parallel increased in complexity, diversifying their output parameters as they progressed in view to recapitulate the most critical aspects such as the dimensionality of cell cultures (2D versus 3D), the mechanical stimuli, the multicellular interactions, the immune interactions and the soluble signaling. Animal models represent the in vivo counterpart to cell lines and are commonly used for studies during the preclinical investigation of cancer therapy to determine the efficacy and safety of novel drugs. They are super to in vitro models in terms of physiological relevance offering imitation of parental tumors and a heterogeneous microenvironment as part of an interacting complex biochemical system. In the present review we describe advantages and limits of major preclinical models used in Oncological Pharmacology

NF-kB Is a Potential Molecular Drug Target in Triple-Negative Breast Cancers

Breast cancer continues to cause significant burden in global health morbidity and mortality. Triple-negative breast cancers (TNBCs) are highly aggressive with poor prognosis and are characterized by lack of expression of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor (Her-2). TNBCs are often resistant to cytotoxic chemotherapy and pose major difficulty in achieving personalized medicine due to their molecular heterogeneity. There is increasing evidence that the aberrant activation of nuclear factor (NF)-kB signaling is a frequent characteristic of TNBCs. We evaluated the effects of different potential NF-kB inhibitors, such as bisindolylmaleimide I (BIS, a selective protein kinase C [PKC] inhibitor),MG132 (a proteasome inhibitor), curcumin (endowed with pleiotropic activities), and dehydroxymethylepoxyquinomicin (an inhibitor of NF-kB translocation into the nucleus) on the constitutive activation of NF-kB present in three TNBC cell lines (SUM149, SUM159, and MDA-MB-231). Wealso evaluated whether MDA-9/Syntenin plays a role in NF-kB activation, as observed in other cancer types. Indeed, silencing experiments with a siRNA anti-MDA-9/Syntenin produced a very strong reduction of NF-kB activation in all the three TNBC cell lines. We conclude that different approaches targeting NF-kB activation might potentially prove useful for innovation in anticancer drug development for TNBCs. Further research that bridge preclinical and clinical investigations with NF-kB inhibitors would be timely and warranted

Recovery of Bioactive Compounds from Marine Organisms: Focus on the Future Perspectives for Pharmacological, Biomedical and Regenerative Medicine Applications of Marine Collagen

Marine environments cover more than 70% of the Earth's surface and are among the richest and most complex ecosystems. In terms of biodiversity, the ocean represents an important source, still not widely exploited, of bioactive products derived from species of bacteria, plants, and animals. However, global warming, in combination with multiple anthropogenic practices, represents a serious environmental problem that has led to an increase in gelatinous zooplankton, a phenomenon referred to as jellyfish bloom. In recent years, the idea of "sustainable development" has emerged as one of the essential elements of green-economy initiatives; therefore, the marine environment has been re-evaluated and considered an important biological resource. Several bioactive compounds of marine origin are being studied, and among these, marine collagen represents one of the most attractive bio-resources, given its use in various disciplines, such as clinical applications, cosmetics, the food sector, and many other industrial applications. This review aims to provide a current overview of marine collagen applications in the pharmacological and biomedical fields, regenerative medicine, and cell therapy

NF-\u3baB is a potential pharmacological target in triple negative breast cancers.

Triple negative breast cancers (TNBCs), characterized by lack of estrogen, progesterone and HER2 receptors, are a highly heterogenous group of tumors which account for about 20% to 25% of all breast cancers. TNBCs are often associated with epithelial-mesenchymal transition and a high propensity for early metastasis. Since no molecularly-targeted therapeutic agents are clinically available for TNBCs, these tumors, which are frequently resistant to cytotoxic chemotherapy, remain difficult to treat. Nevertheless, progress is being made in the finding of molecular alterations typical of TNBCs toward which to focus therapeutic efforts

Expression of the IAPs in multidrug resistant tumor cells

We have investigated the expression of the IAPs (inhibitory of apoptosis proteins) in the human HL-60 leukemia and in its multidrug resistant, P-glycoprotein (P-gp) over-expressing variant, HL-60R. HL-60R exhibits resistance to apoptosis induced from P-gp substrate drugs and also from other triggers (cisplatin, TNF-alpha, Fas ligation, TRAIL, IFN-gamma and serum starvation) not related to the multidrug transporter. Except for c-IAP-1 mRNA, HL-60R significantly over-expressed both the mRNAs and the proteins of all the IAPs studied, i.e. c-IAP-1, c-IAP-2, XIAP, NAIP and survivin. Determination of the DNA-binding capacity of NF-kappaB (p50 or p65 subunits) indicated that, while HL-60 cells show constitutive activation of p50 only, HL-60R cells contain the activated forms of both p50 and p65. Since p65 is necessary to form the NF-kappaB heterodimers able to increase transcription, its presence in HL-60R cells might well correlate to their increased levels of IAPs and, possibly of P-gp, which, reportedly, are NF-kappaB target genes. These results underline the possible role that the coordinated over-expression of the different IAPs may play in tumor cell resistance to drug induced apoptosis. Inhibition of NF-kappaB might be a useful strategy to block their up-regulation