Phosphorylation of NuMA by Aurora‐A kinase in PC‐3 prostate cancer cells affects proliferation,survival, and interphase NuMA localization

Aurora‐A is a serine/threonine kinase that has oncogenic properties in vivo. The expression and kinase activity of Aurora‐A are up‐regulated in multiple malignancies. Aurora‐A is a key regulator of mitosis that localizes to the centrosome from the G2 phase through mitotic exit and regulates mitotic spindle formation as well as centrosome separation. Overexpression of Aurora‐A in multiple malignancies has been linked to higher tumor grade and poor prognosis through mechanisms that remain to be defined. Using an unbiased proteomics approach, we identified the protein nuclear mitotic apparatus (NuMA) as a robust substrate of Aurora‐A kinase. Using a small molecule Aurora‐A inhibitor in conjunction with a reverse in‐gel kinase assay (RIKA), we demonstrate that NuMA becomes hypo‐phosphorylated in vivo upon Aurora‐A inhibition. Using an alanine substitution strategy, we identified multiple Aurora‐A phospho‐acceptor sites in the C‐terminal tail of NuMA. Functional analyses demonstrate that mutation of three of these phospho‐acceptor sites significantly diminished cell proliferation. In addition, alanine mutation at these sites significantly increased the rate of apoptosis. Using confocal immunofluorescence microscopy, we show that the NuMA T1804A mutant mis‐localizes to the cytoplasm in interphase nuclei in a punctate pattern. The identification of Aurora‐A phosphorylation sites in NuMA that are important for cell cycle progression and apoptosis provides new insights into Aurora‐A function. J. Cell. Biochem. 114: 823–830, 2013. © 2012 Wiley Periodicals, Inc.     

Aptamers: A promising tool for cancer imaging,diagnosis, and therapy

Aptamers are a group of molecules, which can specifically bind, track, and inhibit target molecules, comprising DNA aptamers, RNA aptamers, and peptide aptamers. So far, there are much progress about developing novel aptamers and their expansile applications. This prospect systematically introduces the composition and technological evolution of aptamers, and then focuses on the application of aptamers in cancer diagnosis, imaging, and therapy. Following this, we discuss the potential to harness aptamers in discovering the biomarker of stem cells, which is favorable for us to study the normal developmental or abnormal pathological process of tissue and to deliver drugs into target cells or tissues in the future. J. Cell. Biochem. 114: 250–255, 2013. © 2012 Wiley Periodicals, Inc.     

Upregulation of recepteur d'origine nantais tyrosine kinase and cell invasiveness via early growth response-1 in gastric cancer cells

Abnormal accumulation and activation of the recepteur d'origine nantais (RON) has been implicated in carcinogenesis of epithelial tumors. RON expression was induced by the tumor promoter, phorbol 12-myristate 13-acetate (PMA), in gastric adenocarcinoma AGS cells. Studies with deleted and site-directed mutagenesis of Egr-1 promoter and with expression vectors encoding Egr-1 confirmed that Egr-1 is essential for RON expression. In addition, AGS cells pretreated with PMA showed remarkably enhanced invasiveness, which was partially abrogated by siRNA-targeted RON and Egr-1. These results suggest that tumor promoter induces RON expression via Egr-1, which, in turn, stimulates cell invasiveness in AGS cells.     

Clinical significance of circulating interleukin-23 as a prognostic factor in breast cancer patients

Little is known about specific IL‐23 alterations associated with breast cancer and the data available are still controversial. Therefore, the evaluation of changes in serum IL‐23 levels may add further information on the role of this cytokine in breast cancer patients. The aim of this study was to evaluate prospectively the prognostic importance of circulating IL‐23 in patients with untreated breast cancer, respect to healthy controls, and the association with clinico‐pathological variables. The study involved 50 women diagnosed with stages I–IV breast cancer and 38 healthy controls. Of the 50 breast cancer patients, 37 women were recruited prior to their initial adjuvant chemotherapy and 13 prior to receive first line chemotherapy for metastatic disease. Adjuvant chemotherapy patients were at least in their 4th week post‐surgery. IL‐23 serum concentrations were measured by a quantitative enzyme immunoassay technique. We found a statistically significant higher systemic cytokine value in women with cancer in comparison with the control group (14.52 ± 11.39 pg/ml vs. 6.35 ± 4.63 pg/ml, P < 0.0001). Patients with shorter overall survival presented higher IL‐23 values, suggesting a negative prognostic correlation. There was no significant differences in IL‐23 levels among patients according to the biomolecular characteristics, the different subtypes and the presence of metastatic disease. This work investigated, for the first time, the role of IL‐23 in breast cancer patients showing a significant increase respect the control group. However, further validations are needed in larger studies to better investigate the implications of IL‐23 increase in these patients. J. Cell. Biochem. 113: 2122–2125, 2012. © 2012 Wiley Periodicals, Inc.     

HIFs,angiogenesis, and cancer

Tumor hypoxia was first described in the 1950s by radiation oncologists as a frequent cause of failure to radiotherapy in solid tumors. Today, it is evident that tumor hypoxia is a common feature of many cancers and the master regulator of hypoxia, hypoxia‐inducible factor‐1 (HIF‐1), regulates multiple aspects of tumorigenesis, including angiogenesis, proliferation, metabolism, metastasis, differentiation, and response to radiation therapy. Although the tumor hypoxia response mechanism leads to a multitude of downstream effects, it is angiogenesis that is most crucial and also most susceptible to molecular manipulation. The delineation of molecular mechanisms of angiogenesis has revealed a critical role for HIF‐1 in the regulation of angiogenic growth factors. In this article, we review what has been described about HIF‐1: its structure, its regulation, and its implication for cancer therapy and we focus on its role in angiogenesis and cancer. J. Cell. Biochem. 114: 967–974, 2013. © 2012 Wiley Periodicals, Inc.     

N-glycan biosynthesis inhibitors induce in vitro anticancer activity in colorectal cancer cells

During malignant transformation, changes in the expression profile of glycans may be involved in a variety of events, including the loss of cell-cell and cell-matrix adhesion, migration, invasion, and evasion of apoptosis. Therefore, modulation of glycan expression with drugs has promising therapeutic potential for various cancer types. In this study, we investigated the in vitro anticancer activity of the N-glycan biosynthesis inhibitors (swainsonine and tunicamycin) in cells derived from colorectal cancer (CRC). We also examined whether these inhibitors are able to induce radiosensitization and toxicity when used in combination with cisplatin or irinotecan, two current anticancer drugs. Our results show that treatment with tunicamycin inhibits cellular mechanisms related to the malignant phenotype, such as anchorage-dependent and anchorage-independent colony formation, migration and invasion, in undifferentiated HCT-116 colon cancer cells, whereas swainsonine only inhibits cell migration. We also observed that tunicamycin, but not swainsonine, caused radiosensitivity in HCT-116 cells. Moreover, the combination of swainsonine with cisplatin or irinotecan enhanced their toxicity in HCT-116 cells, while the combination of tunicamycin with these drugs had no effect. Given these results, we suggest that the modulation of N-glycan biosynthesis appears to be a potential therapeutic tool for CRC treatment because inhibition of this process induced anticancer activity in vitro. Additionally, the inhibition of the N-glycan biosynthesis in combination with chemotherapic drugs is a promising therapeutic strategy for enhancing radiation therapy.