Myopodin-Mediated Suppression of Prostate Cancer Cell Migration Involves Interaction with Zyxin

Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
Cancer Research (Impact Factor: 9.33). 09/2006; 66(15):7414-9. DOI: 10.1158/0008-5472.CAN-06-0227
Source: PubMed


Myopodin was identified as a tumor suppressor gene that is frequently deleted in aggressive prostate cancer. Expression of myopodin protein suppresses both tumor growth and metastasis in vitro and in vivo. In the present study employing a yeast two-hybrid system, we found that zyxin, a molecule known to regulate cell motility and migration, binds with myopodin with high affinity. The binding between zyxin and myopodin seems to be direct. Screening of a series of myopodin deletion mutants and peptide competition analyses revealed that myopodin is bound by zyxin at a site located within the sequence of the 19 amino acids at the myopodin COOH terminus. Importantly, this is the same region where the tumor suppressor activity of myopodin is located. The motility and invasion suppression activity of myopodin were significantly weakened in myopodin mutants lacking this sequence. Thus, our studies suggest that zyxin may be a critical functional regulator of myopodin.

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    • "This will reduce the co-eluting peptides that would otherwise result in erroneous product ion MS-MS spectra negating the accurate relative quantification efficiency and protein identification accuracy (Fournier et al., 2007). The modulated proteins identified were implicated in the inflammation response (Albini et al., 2007; Albini, Tosetti, Benelli, & Noonan, 2005; DeSouza et al., 2005; Goldstraw, Fitzpatrick, & Kirby, 2007; Nelson, DeMarzo, DeWeese, & Isaacs, 2005), the modulation of the androgen (Cheung-Flynn et al., 2005; De Leon et al., 2011; Hildenbrand et al., 2011; McKeen et al., 2011; Milad et al., 1995; Miyoshi et al., 2003; Nelson et al., 2005; M. H. Yang & Sytkowski, 1998), and prostate cancer metastasis (Ablin, Kynaston, Mason, & Jiang, 2011; Dabbous, Jefferson, Haney, & Thomas, 2011; Di Cristofano et al., 2010; Grisendi, Mecucci, Falini, & Pandolfi, 2006; Hale, Price, Sanchez, Demark-Wahnefried, & Madden, 2001; Jiang & Ablin, 2011; Khanna et al., 2004; C. J. Kim, Sakamoto, Tambe, & Inoue, 2011; Krust, El Khoury, Nondier, Soundaramourty, & Hovanessian, 2011; Moretti et al., 2011; Okuda et al., 2000; Planche et al., 2011; Sun, Song, et al., 2011; Sun, Zhao, et al., 2011; Weng, Ahlen, Astrom, Lui, & Larsson, 2005; Yu & Luo, 2006), as essential hallmark features for these prostate cancer tissue specimens. Another interesting finding that also goes toward validating the accuracy of the proteomic method is the differential expression of several prostate specific cancer markers such as the prostatespecific transglutaminase, the prostate associated gene 4 protein, the prostatic acid phosphatase, and the prostate specific membrane antigen (see Figure 2). "
    Biomarker, 03/2012; , ISBN: 978-953-51-0577-0
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    • "PIP5K1C and PXN are necessary for cellular adhesion in a variety of cell types [37], [38]. ZYX is a phosphoprotein which is concentrated at focal adhesions and along the actin cytoskeleton and regulates cellular adhesion and migration [39], [40], [41], [42], [43], [44]. The effect of these and other genes in the two pathways identified which are targeted by miR-886-3p, are consistent with the dramatic effect on cellular proliferation and migration observed in our miR-886-3p functional studies. "
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    ABSTRACT: The molecular basis and characteristics of familial non-medullary thyroid cancer are poorly understood. In this study, we performed microRNA (miRNA) profiling of familial and sporadic papillary thyroid cancer tumor samples. Genome wide miRNA profiling of sporadic and familial papillary thyroid cancer was performed. Differentially expressed miRNAs were validated by quantitative RT-PCR. Ectopic expression of miR-886-3p in thyroid cancer lines was performed to identify pathways targeted by the miRNA, as well as, to determine its effect on tumor cell biology. We found four differentially expressed miRNAs between familial and sporadic papillary thyroid cancer tumor samples. MiR-886-3p and miR-20a were validated to be differentially expressed by 3- and 4-fold, respectively. Pathway analysis of genome-wide expression data on cells overexpressing miR-886-3p and target prediction analysis showed genes involved in DNA replication and focal adhesion pathways were regulated by miR-886-3p. Overexpression of miR-886-3p in thyroid cancer cell lines significantly inhibited cellular proliferation, the number and size of spheroids and cellular migration. Additionally, overexpression of miR-886-3p increased the number of cells in S phase. Our findings for the first time suggest that miR-886-3p plays an important role in thyroid cancer tumor cell biology and regulates genes involved in DNA replication and focal adhesion. Thus, miR-886-3p may play a role in the initiation and or progression of papillary thyroid cancer.
    PLoS ONE 10/2011; 6(10):e24717. DOI:10.1371/journal.pone.0024717 · 3.23 Impact Factor
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    • "Wound Healing assays—For the wound healing assay (Yu and Luo, 2006), tetracycline induced or uninduced cells were cultured in 6-well culture plates in the medium described above, and transfected with siRNA for 72 hours. At the surface of confluenced culture plate, a plastic pipette tip was drawn across the center of the well to produce a clean crevice that was 1 mm wide. "
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    ABSTRACT: Myopodin is a tumor-suppressor gene that suppresses growth of prostate and urothelial carcinomas. However, the mechanism of myopodin tumor-suppressor activity or signaling that leads to activation of myopodin remains unclear. In this report, we showed that the N-terminus of myopodin binds integrin-linked kinase (ILK) both in vivo and in vitro. An ILK interaction motif of 78 amino acids (amino acids 82-157) was identified in the N-terminus region of myopodin. Induction of ILK-dependent kinase activity by integrin α7 led to phosphorylation of myopodin both in vivo and in vitro. Knocking down ILK dramatically reduced the inhibition of cell growth and motility mediated by myopodin. A mutant of myopodin lacking the ILK interaction motif is inactive in suppressing the growth and motility of PC3 cells. As a result, this study showed a novel and critical signaling pathway that leads to activation of myopodin.
    Oncogene 06/2011; 30(49):4855-63. DOI:10.1038/onc.2011.200 · 8.46 Impact Factor
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