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Nitric oxide (NO) has been suggested to be a pathophysiological modulator of cell proliferation, cell cycle arrest, and apoptosis. In this context, NO can exert opposite effects under diverse conditions. Indeed, several studies have indicated that low relative concentrations of NO seem to favor cell proliferation and antiapoptotic responses and higher levels of NO favor pathways inducing cell cycle arrest, mitochondria respiration, senescence, or apoptosis. Here we report the effects of NO on both promotion and inhibition of cell proliferation, in particular in regard to cardiovascular disease, diabetes, and stem cells. Moreover, we focus on molecular mechanisms of action involved in the control of cell cycle progression, which include both cyclic guanosine monophosphate-dependent and -independent pathways. This growing field may lead to broad and novel targeted therapies against cardiovascular diseases, especially concomitant type 2 diabetes, as well as novel bioimaging NO-based diagnostic tools.

In the last decades, transcriptome profiling has been one of the most utilized approaches to investigate human diseases at the molecular level. Through expression studies, many molecular biomarkers and therapeutic targets have been found for several human pathologies. This number is continuously increasing thanks to total RNA sequencing. Indeed, this new technology has completely revolutionized transcriptome analysis allowing the quantification of gene expression levels and allele-specific expression in a single experiment, as well as to identify novel genes, splice isoforms, fusion transcripts, and to investigate the world of non-coding RNA at an unprecedented level. RNA sequencing has also been employed in important projects, like ENCODE (Encyclopedia of the regulatory elements) and TCGA (The Cancer Genome Atlas), to provide a snapshot of the transcriptome of dozens of cell lines and thousands of primary tumor specimens. Moreover, these studies have also paved the way to the development of data integration approaches in order to facilitate management and analysis of data and to identify novel disease markers and molecular targets to use in the clinics. In this scenario, several ongoing clinical trials utilize transcriptome profiling through RNA sequencing strategies as an important instrument in the diagnosis of numerous human pathologies.

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Tumor growth requires neoangiogenesis. VEGF is the most potent proangiogenic factor. Dysregulation of hypoxia-inducible factor (HIF) or cytokine stimuli such as those involving the chemokine receptor 4/stromal-derived cell factor 1 (CXCR4/SDF-1) axis are the major cause of ectopic overexpression of VEGF in tumors. Although the CXCR4/SDF-1 pathway is well characterized, the transcription factors executing the effector function of this signaling are poorly understood. The multifunctional Yin Yang 1 (YY1) protein is highly expressed in different types of cancers and may regulate some cancer-related genes. The network involving CXCR4/ YY1 and neoangiogenesis could play a major role in cancer progression. In this study we have shown that YY1 forms an active complex with HIF-1α at VEGF gene promoters and increases VEGF transcription and expression observed by RT-PCR, ELISA, and Western blot using two different antibodies against VEGFB. Long-term treatment with T22 peptide (a CXCR4/SDF-1 inhibitor) and YY1 silencing can reduce in vivo systemic neoangiogenesis (P < 0.01 and P < 0.05 vs. control, respectively) during metastasis. Moreover, using an in vitro angiogenesis assay, we observed that YY1 silencing led to a 60% reduction in branches (P < 0.01) and tube length (P < 0.02) and a 75% reduction in tube area (P < 0.001) compared with control cells. A similar reduction was observed using T22 peptide. We demonstrated that T22 peptide determines YY1 cytoplasmic accumulation by reducing its phosphorylation via downregulation of AKT, identifying a crosstalk mechanism involving CXCR4/YY1. Thus, YY1 may represent a crucial molecular target for antiangiogenic therapy during cancer progression.cancer | metastasis | oncogene A ngiogenesis is critical to the growth, invasion, and metastasis of human tumors (1, 2). Because targeting angiogenesis has emerged as a promising strategy for the therapeutic treatment of cancer, understanding the transcriptional regulation that determines the tumor angiogenic phenotype has become of cardinal importance (3).Yin Yang 1 (YY1) protein has diverse roles in cancer development (4) including drug resistance (5, 6) and transcriptional regulation of many genes (7). YY1 also is involved in the regulation of angiogenesis during malignancy (8). Certainly, YY1 silencing reduced intrametastatic and systemic neoangiogenesis interacting with the chemokine receptor 4 (CXCR4) pathway in osteosarcoma (SaOS) cells (8). Interestingly, CXCR4 is required for cancer progression and blood supply via neoangiogenesis (9-11). Accordingly, some of CXCR4 inhibitors are being evaluated in clinical trials as adjunct therapy (12) (http://clinicaltrials.gov). The network that involves CXCR4/YY1 and neoangiogenesis could play a major role in cancer pathobiology. In this study, we demonstrate that YY1 has a crucial role during neoangiogenesis and elucidate the mechanism by which CXCR4/YY1 inhibition reduces VEGF-dependent neoangiogenesis. ResultsEffects of YY1 Silencing and CXCR4 Inhibition on Angiogenesis. To monitor angiog...

We examined the peroxisome proliferator-activated receptor ␥ (PPARG) locus in an attempt to identify expressed sequence tags and/or conserved non-coding sequences in the intron sequences containing open reading frames and potentially able to encode new proteins. We identified a new PPARG transcript, defined ␥ORF4, which harbors a readthrough in intron 4. The expected translated protein lacks the ligand-binding domain encoded by exons 5 and 6. We identified the transcript in human tumor cell lines and tissues, synthesized the cDNA, and cloned it in expression vectors. Using transient transfections, we found that ␥ORF4 cDNA is translated into a predominantly nuclear protein that does not transactivate a reporter gene. Moreover, the isoform is dominant negative versus PPAR␥. Interestingly, ␥ORF4 was expressed in vivo in a series of sporadic colorectal cancers. In some cases, it was expressed, albeit at lower levels, also in the mucosa adjacent to the tumors, suggesting that it may be related to tumorigenesis. A tumorigenic effect of ␥ORF4 is in line with our finding that ␥ORF4 has not only lost the capacity to restrain cell growth but has acquired the potential to stimulate it. In conclusion, this study demonstrates that ␥ORF4 is expressed in vivo, that it has lost some PPAR␥ properties, and that it affects PPAR␥ functioning. The ability to counteract PPAR␥ suggests that ␥ORF4 plays a role in the pathogenesis of colorectal cancers.