51741

WWOX

WW domain containing oxidoreductase;WWOX;WW domain containing oxidoreductase

WW domain-containing oxidoreductase|WW domain-containing protein WWOX|fragile site FRA16D oxidoreductase|short chain dehydrogenase/reductase family 41C member 1|short chain dehydrogenase/reductase family 41C, member 1

16q23

protein-coding

The hypoxic microenvironment of bone marrow favours the bone metastasis process. Hypoxia inducible factor (HIF)-1alpha is hallmark for hypoxia, correlating with poor prognosis and radio/chemotherapy resistance of primary-breast carcinoma. For bone metastasis, the molecular mechanisms involved in HIF-1alpha expression and HIF-1 (alpha/beta heterodimer)-transcription factor activity are scarcely known. We studied the role played by HIF-1 in the cross-talk between neoplastic and supportive-microenvironmental cells. Also, WWdomain-containing oxidoreductase (Wwox) and transcriptional co-activator with PDZ-binding motif (TAZ) were taken into consideration evaluating whether these Hippo-pathway effectors affect bone-metastatic phenotype through HIF-1 activity. Considering bone-metastasis specimens, nuclear HIF-1alpha-TAZ co-localisation occurred in neoplastic and supportive cells, such as fibroblasts and endotheliocytes. Based on these data, the functional importance was verified using 1833-bone metastatic clone under hypoxia: nuclear HIF-1alpha and TAZ expression increased and co-immunoprecipitated, activating HIF-1-DNA binding and transactivation. In contrast, Wwox localised at perinuclear level in neoplastic cells of bone metastasis, being almost absent in supportive cells, and Wwox-protein expression diminished in hypoxic-1833 cells. Thus, TAZ regulation of HIF-1 activity might be important for bone-secondary growth, participating in metastasis-stroma cross-talk. Further, TAZ and HIF-1alpha-protein levels seemed correlated. In fact, blocking cyclooxygenase-2 with NS398 in hypoxic-1833 cells, not only HIF-1alpha decreased but also molecular-mechanism(s) upstream of the Hippo pathway were triggered: LATS-dependent TAZ phosphorylation seemed responsible for TAZ nucleus/cytoplasm translocation and degradation. In the 1833-xenograft model, NS398 largely prevented the outgrowth of bone-metastatic cells, probably related to remarkable-extracellular matrix assembly. We gained clinical insight into HIF-1alpha and TAZ as candidate biomarkers for bone avidity, relevant for early-therapeutic intervention against bone metastasis.

Using the PCR-based subtractive messenger RNA hybridization assay described in this paper, we isolated a hitherto uncharacterized gene, transmembrane protein 207 (TMEM207), which was selectively expressed in collagen gel-invading cultured signet-ring cell carcinoma KATO-III cells. TMEM207 has a C-terminal proline-rich PPxY motif, which binds to the WW domain-containing oxidoreductase, WWOX. Enforced expression of TMEM207 significantly increased Matrigel invasion activity of KATO-III cells in vitro without affecting cell growth. In contrast, expression of TMEM207 with mutations in the PPxY motif did not significantly increase Matrigel invasion activity of KATO-III cells. Immunohistochemical staining showed that TMEM207 was strongly expressed in 7 of 30 gastric signet-ring cell carcinoma tissue specimens. Notably, TMEM207 expression was associated with the depth of cancer invasion and the presence of lymph node metastasis. The results of co-immunoprecipitation followed by western immunoblotting showed that TMEM207 is bound to WWOX in a PPxY motif-dependent manner. Small interfering RNA-mediated downregulation of WWOX also significantly increased Matrigel invasion activity of KATO-III cells. Notably, exogenous expression of TMEM207 impaired the WWOX-mediated repression of Matrigel invasion activity of another cultured signet-ring cell carcinoma cell line, NUGC-4 cells. Recent studies have highlighted the fact that WWOX acts as a tumor suppressor factor in various malignant tumors, including gastric cancer. On the basis of these findings and the results of the present study, we think that overexpression of TMEM207 may facilitate invasive activity and metastasis of gastric signet-ring cell carcinoma, which possibly occur through binding to WWOX and attenuation of its function.

Head and neck squamous cell carcinoma (HNSCC) is a prevalent disease worldwide, and the survival of HNSCC has not improved significantly over the last few decades. MicroRNAs (miRNAs) have an important regulatory role during carcinogenesis. Our study investigated the pathogenic implications of miR-134 in head and neck carcinogenesis. The clinicopathologic implications of miR-134 in HNSCC were investigated using expression assays and the functional role of miR-134 in HNSCC pathogenesis was determined using ectopic expression, knockdown and reporter assay experiments. Xenographic tumorigenesis and orthotopic nodal metastasis were assayed in mouse models. In situ hybridization and immunohistochemistry were used to detect the expression of miR-134 and the WWOX gene in human HNSCC. The results indicated that miR-134 was upregulated in HNSCC tissues relative to control mucosa. High expression of miR-134 was associated with nodal metastasis and mortality of patients. Decreased plasma miR-134 levels after tumor ablation indicated a better prognosis for patients. Multivariate analysis showed that high miR-134 expression in HNSCC was an independent predictor of poor survival. Ectopic miR-134 expression significantly enhanced in vitro oncogenic phenotypes and the orthotopic growth and metastasis of HNSCC cells. miR-134 targeted WW domain-containing oxidoreductase (WWOX) gene and cell invasion enhanced by miR-134 expression was abrogated by ectopic WWOX expression in HNSCC cells. miR-134 expression was reversely associated with the WWOX expression in HNSCC tissues. Evidences from our study substantiated that miR-134 expression contributes to head and neck carcinogenesis by targeting the WWOX.

BACKGROUND AND OBJECTIVES: We aimed to evaluate the expression levels of the tumor suppressor WOX1 in nervous system tumors and its co-expression with p53 and neurofibromatosis type 2/merlin (NF2) tumor suppressor gene products. METHODS: Immunohistochemistry, western blotting and in situ hybridization were used for WOX1 protein and WWOX mRNA expression. Immunofluorescence and electron microscopical immunohistochemistry were performed for colocalization of gene products. RESULTS: WOX1 expression is low in normal cortical neurons, mainly on the axon fibers, whereas there is moderate to high immunoreactivity in the cytosol and nuclei of certain tumor cells. In the microcystic (WHO grade I) and malignant (WHO grade III) meningiomas, WOX1 expression is intense, but various in transitional (WHO grade I) and atypical (WHO grade II) subtypes. WOX1 levels are moderate to high in the menigiotheliomatous area, but relatively low in the fibroblastic area. WOX1 and NF2/merlin, but not p53, colocalized in certain tumor cells, primarily at the borders of nuclei. Schwannoma and astrocytoma specimens stained moderately to strongly positive for the WOX1 protein. Interestingly, the expression of WOX1, NF2/merlin and mutant p53 is intense in high grade glioblastoma, but WOX1 expression is low in metastatic carcinoma or adenocarcinoma. CONCLUSIONS: The expression of WOX1 on different types of nervous system tumors, including primary and metastatic tumors, is differential.