The Coiled-coil Domain Is the Structural Determinant for Mammalian Homologues of Drosophila Sina-mediated Degradation of Promyelocytic Leukemia Protein and Other Tripartite Motif Proteins by the Proteasome

Mammalian homologues of Drosophila Seven in Absentia (SIAHs) target for proteasome-mediated degradation several factors involved in cell growth and tumorigenesis. Here we show that SIAH-1/2 binds and targets for proteasome-mediated degradation the putative tumor suppressor and tripartite motif (TRIM) family member PML, leading to the loss of its transcriptional co-activating properties and a reduction in the number of endogenous PML nuclear bodies. Association with PML requires the substrate-binding domain (SBD) of SIAH-1/2 through an interacting surface apparently distinct from those predicted by the structural studies, or shown experimentally to mediate binding to SIAH-associated factors. Within PML, the coiled-coil domain is required for Siah- and proteasome-mediated degradation, and deletions of regions critical for the integrity of this region impair the ability of Siah to trigger PML-RAR degradation. Fusion of the coiled-coil domain to heterologous proteins resulted in the capacity of mSiah-2 to target their degradation. All of the TRIM proteins tested were degraded upon mSiah-2 overexpression. Finally, we show that the fusion protein PML-RAR (that retains the coiled-coil domain), which causes acute promyelocytic leukemias, is also a potential substrate of mSiah-2. As a result of mSiah-2 overexpression and subsequent degradation of the fusion protein, the arrest in hematopoietic differentiation because of expression of PML-RAR is partially rescued. These results identify PML and other TRIMs as new factors post-translationally regulated by SIAH and involve the coiled-coil region of PML and of other SIAH substrates as a novel structural determinant for targeted degradation

Antioncogenic Effects of Transient Receptor Potential Vanilloid 1 in the Progression of Transitional Urothelial Cancer of Human Bladder

The progression of normal cells to a tumorigenic and metastatic state involves the accumulation of mutations in multiple key signaling proteins, encoded by oncogenes and tumor suppressor genes. Recently, members of the TRP channel family have been included in the oncogenic and tumor suppressor protein family. TRPM1, TRPM8, and TRPV6 are considered to be tumor suppressors and oncogenes in localized melanoma and prostate cancer, respectively. Herein, we focus our attention on the antioncogenic properties of TRPV1. Changes in TRPV1 expression occur during the development of transitional cell carcinoma (TCC) of human bladder. A progressive decrease in TRPV1 expression as the TCC stage increases triggers the development of a more aggressive gene phenotype and invasiveness. Finally, downregulation of TRPV1 represents a negative prognostic factor in TCC patients. The knowledge of the mechanism controlling TRPV1 expression might improve the diagnosis and new therapeutic strategies in bladder cancer

Role of Capsaicin in Oxidative Stress and Cancer

Capsaicin has been shown to induces apoptosis in various trasformed cell types in vitro and in vivo

Capsaicin promotes a more aggressive gene expression phenotype and invasiveness in null-TRPV1 urothelial cancer cells

Capsaicin (CPS) has been found to exhibit either tumor promoting or suppressing effects, many of which are mediated by the specific transient receptor potential vanilloid type-1 (TRPV1). Herein, we provide evidence that CPS treatment induced a more aggressive gene phenotype and invasiveness in 5637 cells-lacking TRPV1 receptor. CPS treatment of 5637 cells induced upregulation of pro-angiogenetic (angiopoietin 1, angiopoietin 2 and vascular endothelial growth factor), pro-invasive and pro-metastatic genes (MMP1, MMP9, TIMP1, TIMP3, granzyme A (GZMA), NM23A and S100A) with a downregulation of apoptotic genes (Fas/CD95 and tumor necrosis factor receptor superfamily member 1A). CPS increased the invasiveness of 5637 cells by triggering IGF (insulin-like growth factor)-1 release, GZMA and MMP9 activation, alpha-tubulin disassembly and cytoskeleton degradation. Finally, in order to evaluate the relationship between the lack of TRPV1 expression and increased CPS-induced invasiveness, we transfected 5637 cells with the TRPV1 complementary DNA (cDNA) sequence. We found that TRPV1-expressing cells show CPS-mediated calcium level increase, growth inhibition and apoptosis. Moreover, CPS-induced migration and MMP9 activation were reverted, suggesting an inhibitory role played by TRPV1 in urothelial cancer cell invasion and metastasis

IL-22 mRNA in peripheral blood mononuclear cells from allergic rhinitic and asthmatic pediatric patients

T helper (T(H) )-17 lymphocytes are characterized by the expression of many regulatory cytokines, including IL-17A and IL-22, but at present no clinical data are available on the expression of these cytokines in peripheral blood mononuclear cells (PBMC) from allergic asthmatic and rhinitic (AR) children. The aim of this study was to investigate a possible relationship between IL-22 and IL-17A mRNAs and clinical parameters in seroatopic, AR, and asthmatic children. The study, conducted during the pollen season, included 18 healthy and 18 allergic (n=9 asthmatic and n=9 rhinitic) children. Serum total and specific IgE, eosinophil count, and skin prick test were performed; in addition, IL-22 and IL-17A mRNA levels were detected in PBMC from healthy and allergic subjects by quantitative real-time PCR. Despite the absence of the mRNA for the IL-17A cytokine, IL-22 expression was found in PBMC from asthmatic patients, with increased IL-22 mRNA levels in patients with chronic severe respect to those with moderate asthma. A positive correlation between IL-22 mRNA and serum total IgE levels was found in asthmatic children. In addition, higher IL-22 and IL-17A mRNA levels were detected in both AR and asymptomatic seroatopic children, compared to healthy individuals, and a correlation between IL-22 and IL17A mRNA and serum total IgE levels was demonstrated. Moreover, the mRNA level of retinoic acid-related orphan receptor C, the T(H) 17 transcription factor, was found to be increased in AR but not in asthmatic patients. This study provides the first evidence that IL-22 mRNA might be expressed in chronic severe asthmatic and AR children. The expression of IL-22 and IL-17A mRNAs in asymptomatic monosensitized seroatopic children suggests a role of these cytokines in the early events involved in the development of these allergic diseases

Expression of transient receptor potential vanilloid-1 (TRPV1) in urothelial cancers of human bladder: Relation to clinicopathological and molecular parameters

International audienceAims: The aim of this study was to evaluate the expression of transient receptor potential vanilloid type-1 chennel protein (TRPV1) in normal and tumor urothelial tissues; to correlate TRPV1 expression with clinico-pathological parameters and with disease-specific survival. Methods and Results: TRPV1 expression was analyzed in normal and tumor urothelial samples at both mRNA and protein levels by Real-Time PCR and immunohistochemistry, respectively. TRPV1 down-regulation was found in UC specimens, which correlates with tumor progression. Moreover, TRPV1 mRNA levels were associated to clinico-pathological parameters to asses the role of TRPV1 down-regulation as a negative prognostic factor for survival. Kaplan-Meier survival analysis demonstrated a significantly shorter survival in patients showing TRPV1 mRNA down-regulation. Multivariate Cox regression analysis further indicated that TRPV1 mRNA expression retained its significance as an independent risk factor. Conclusions: The progression of UC of human bladder is associated with a marked decrease of TRPV1 expression, with a progressive loss in high-grade muscle invasive UC. Down-regulation of TRPV1 mRNA expression may represent an independent negative prognostic factor for the survival probability of bladder cancer patients

Loss of pericentromeric DNA methylation pattern in human glioblastoma is associated with altered DNA methyltransferases expression and involves the stem cell compartment.

Cancer is generally characterized by loss of CG dinucleotides methylation resulting in a global hypomethylation and the consequent genomic instability. The major contribution to the general decreased methylation levels seems to be due to demethylation of heterochromatin repetitive DNA sequences. In human immunodeficiency, centromeric instability and facial anomalies syndrome, demethylation of pericentromeric satellite 2 DNA sequences has been correlated to functional mutations of the de novo DNA methyltransferase 3b (DNMT3b), but the mechanism responsible for the hypomethylated status in tumors is poorly known. Here, we report that human glioblastoma is affected by strong hypomethylation of satellite 2 pericentromeric sequences that involves the stem cell compartment. Concomitantly with the integrity of the DNMTs coding sequences, we report aberrations in DNA methyltrasferases expression showing upregulation of the DNA methyltransferase 1 (DNMT1) and downregulation of the de novo DNA methyltransferase 3a (DNMT3a). Moreover, we show that DNMT3a is the major de novo methyltransferase expressed in normal neural progenitor cells (NPCs) and its forced re-expression is sufficient to partially recover the methylation levels of satellite 2 repeats in glioblastoma cell lines. Thus, we speculate that DNMT3a decreased expression may be involved in the early post-natal inheritance of an epigenetically altered NPC population that could be responsible for glioblastoma development later in adult life