51
|
Park AR, Oh D, Lim SH, Choi J, Moon J, Yu DY, Park SG, Heisterkamp N, Kim E, Myung PK, Lee JR. Regulation of dendritic arborization by BCR Rac1 GTPase-activating protein, a substrate of PTPRT. J Cell Sci 2012; 125:4518-31. [PMID: 22767509 DOI: 10.1242/jcs.105502] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Dendritic arborization is important for neuronal development as well as the formation of neural circuits. Rac1 is a member of the Rho GTPase family that serve as regulators of neuronal development. Breakpoint cluster region protein (BCR) is a Rac1 GTPase-activating protein that is abundantly expressed in the central nervous system. Here, we show that BCR plays a key role in neuronal development. Dendritic arborization and actin polymerization were attenuated by overexpression of BCR in hippocampal neurons. Knockdown of BCR using specific shRNAs increased the dendritic arborization as well as actin polymerization. The number of dendrites in null mutant BCR(-/-) mice was considerably increased compared with that in wild-type mice. We found that the function of the BCR GTPase-activating domain could be modulated by protein tyrosine phosphatase receptor T (PTPRT), which is expressed principally in the brain. We demonstrate that tyrosine 177 of BCR was the main target of PTPRT and the BCR mutant mimicking dephosphorylation of tyrosine 177 alleviated the attenuation of dendritic arborization. Additionally the attenuated dendritic arborization found upon BCR overexpression was relieved upon co-expression of PTPRT. When PTPRT was knocked down by a specific shRNA, the dendritic arborization was significantly reduced. The activity of the BCR GTPase-activating domain was modulated by means of conversions between the intra- and inter-molecular interactions, which are finely regulated through the dephosphorylation of a specific tyrosine residue by PTPRT. We thus show conclusively that BCR is a novel substrate of PTPRT and that BCR is involved in the regulation of neuronal development via control of the BCR GTPase-activating domain function by PTPRT.
Collapse
Affiliation(s)
- A-Reum Park
- Biomedical Proteomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Korea
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
52
|
Sen A, De Castro I, Defranco DB, Deng FM, Melamed J, Kapur P, Raj GV, Rossi R, Hammes SR. Paxillin mediates extranuclear and intranuclear signaling in prostate cancer proliferation. J Clin Invest 2012; 122:2469-81. [PMID: 22684108 DOI: 10.1172/jci62044] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Accepted: 05/02/2012] [Indexed: 01/26/2023] Open
Abstract
In prostate cancer, the signals that drive cell proliferation change as tumors progress from castration-sensitive (androgen-dominant) to castration-resistant states. While the mechanisms underlying this change remain uncertain, characterization of common signaling components that regulate both stages of prostate cancer proliferation is important for developing effective treatment strategies. Here, we demonstrate that paxillin, a known cytoplasmic adaptor protein, regulates both androgen- and EGF-induced nuclear signaling. We show that androgen and EGF promoted MAPK-dependent phosphorylation of paxillin, resulting in nuclear translocation of paxillin. We found nuclear paxillin could then associate with androgen-stimulated androgen receptor (AR). This complex bound AR-sensitive promoters, retaining AR within the nucleus and regulating AR-mediated transcription. Nuclear paxillin also complexed with ERK and ELK1, mediating c-FOS and cyclin D1 expression; this was followed by proliferation. Thus, paxillin is a liaison between extranuclear MAPK signaling and nuclear transcription in response to androgens and growth factors, making it a potential regulator of both castration-sensitive and castration-resistant prostate cancer. Accordingly, paxillin was required for normal growth of human prostate cancer cell xenografts, and its expression was elevated in human prostate cancer tissue microarrays. Paxillin is therefore a potential biomarker for prostate cancer proliferation and a possible therapeutic target for prostate cancer treatment.
Collapse
Affiliation(s)
- Aritro Sen
- Division of Endocrinology and Metabolism, University of Rochester Medical Center, Rochester, NY, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
53
|
Hoekstra E, Peppelenbosch MP, Fuhler GM. The role of protein tyrosine phosphatases in colorectal cancer. Biochim Biophys Acta Rev Cancer 2012; 1826:179-88. [PMID: 22521639 DOI: 10.1016/j.bbcan.2012.04.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 04/03/2012] [Accepted: 04/04/2012] [Indexed: 01/17/2023]
Abstract
Colorectal cancer is one of the most common oncogenic diseases in the Western world. Several cancer associated cellular pathways have been identified, in which protein phosphorylation and dephosphorylation, especially on tyrosine residues, are one of most abundant regulatory mechanisms. The balance between these processes is under tight control by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). Aberrant activity of oncogenic PTKs is present in a large portion of human cancers. Because of the counteracting role of PTPs on phosphorylation-based activation of signal pathways, it has long been thought that PTPs must act as tumor suppressors. This dogma is now being challenged, with recent evidence showing that dephosphorylation events induced by some PTPs may actually stimulate tumor formation. As such, PTPs might form a novel attractive target for anticancer therapy. In this review, we summarize the action of different PTPs, the consequences of their altered expression in colorectal cancer, and their potential as target for the treatment of this deadly disease.
Collapse
Affiliation(s)
- Elmer Hoekstra
- Department of Gastroenterology and Hepatology, Erasmus MC, University Medical Center Rotterdam, The Netherlands
| | | | | |
Collapse
|
54
|
Abstract
It has long been thought that PTPs (protein tyrosine phosphatases) normally function as tumour suppressors. Recent high-throughput mutational analysis identified loss-of-function mutations in six PTPs in human colon cancers, providing critical cancer genetics evidence that PTPs can act as tumour suppressor genes. PTPRT (protein tyrosine phosphatase receptor-T), a member of the family of type IIB receptor-like PTPs, is the most frequently mutated PTP among them. Consistent with the notion that PTPRT is a tumour suppressor, PTPRT knockout mice are hypersensitive to AOM (azoxymethane)-induced colon cancer. The present review focuses on the physiological and pathological functions of PTPRT as well as the cellular pathways regulated by this phosphatase.
Collapse
|
55
|
Abstract
Melanoma, the most aggressive form of skin cancer, has increased in incidence more rapidly than any other cancer. The completion of the human genome project and advancements in genomics technologies has allowed us to investigate genetic alterations of melanoma at a scale and depth that is unprecedented. Here, we survey the history of the different approaches taken to understand the genomics of melanoma - from early candidate genes, to gene families, to genome-wide studies. The new era of whole-exome and whole-genome sequencing has paved the way for an in-depth understanding of melanoma biology, identification of new therapeutic targets, and development of novel personalized therapies for melanoma.
Collapse
Affiliation(s)
- Vijay Walia
- The Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Euphemia W. Mu
- Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jimmy C. Lin
- Division of Laboratory and Genomic Medicine, Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA
| | - Yardena Samuels
- The Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
56
|
Pasquo A, Consalvi V, Knapp S, Alfano I, Ardini M, Stefanini S, Chiaraluce R. Structural stability of human protein tyrosine phosphatase ρ catalytic domain: effect of point mutations. PLoS One 2012; 7:e32555. [PMID: 22389709 PMCID: PMC3289658 DOI: 10.1371/journal.pone.0032555] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 02/01/2012] [Indexed: 01/25/2023] Open
Abstract
Protein tyrosine phosphatase ρ (PTPρ) belongs to the classical receptor type IIB family of protein tyrosine phosphatase, the most frequently mutated tyrosine phosphatase in human cancer. There are evidences to suggest that PTPρ may act as a tumor suppressor gene and dysregulation of Tyr phosphorylation can be observed in diverse diseases, such as diabetes, immune deficiencies and cancer. PTPρ variants in the catalytic domain have been identified in cancer tissues. These natural variants are nonsynonymous single nucleotide polymorphisms, variations of a single nucleotide occurring in the coding region and leading to amino acid substitutions. In this study we investigated the effect of amino acid substitution on the structural stability and on the activity of the membrane-proximal catalytic domain of PTPρ. We expressed and purified as soluble recombinant proteins some of the mutants of the membrane-proximal catalytic domain of PTPρ identified in colorectal cancer and in the single nucleotide polymorphisms database. The mutants show a decreased thermal and thermodynamic stability and decreased activation energy relative to phosphatase activity, when compared to wild- type. All the variants show three-state equilibrium unfolding transitions similar to that of the wild- type, with the accumulation of a folding intermediate populated at ~4.0 M urea.
Collapse
Affiliation(s)
| | - Valerio Consalvi
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, Rome, Italy
| | - Stefan Knapp
- Structural Genomics Consortium, Oxford University, Oxford, England, United Kingdom
| | - Ivan Alfano
- Structural Genomics Consortium, Oxford University, Oxford, England, United Kingdom
| | - Matteo Ardini
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, Rome, Italy
| | - Simonetta Stefanini
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, Rome, Italy
| | - Roberta Chiaraluce
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, Rome, Italy
| |
Collapse
|
57
|
Zhang P, Zhao Y, Zhu X, Sedwick D, Zhang X, Wang Z. Cross-talk between phospho-STAT3 and PLCγ1 plays a critical role in colorectal tumorigenesis. Mol Cancer Res 2011; 9:1418-28. [PMID: 21840932 DOI: 10.1158/1541-7786.mcr-11-0147] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Hyperphosphorylation at the Y705 residue of signal transducer and activator of transcription 3 (STAT3) is implicated in tumorigenesis of leukemia and some solid tumors. However, its role in the development of colorectal cancer is not well defined. To rigorously test the impact of this phosphorylation on colorectal tumorigenesis, we engineered a STAT3 Y705F knock-in to interrupt STAT3 activity in HCT116 and RKO colorectal cancer cells. These STAT3 Y705F mutant cells fail to respond to cytokine stimulation and grow slower than parental cells. These mutant cells are also greatly diminished in their abilities to form colonies in culture, to exhibit anchorage-independent growth in soft agar, and to grow as xenografts in nude mice. These observations strongly support the premise that STAT3 Y705 phosphorylation is crucial in colorectal tumorigenesis. Although it is generally believed that STAT3 functions as a transcription factor, recent studies indicate that transcription-independent functions of STAT3 also play an important role in tumorigenesis. We show here that wild-type STAT3, but not STAT3 Y705F mutant protein, associates with phospholipase Cγ1 (PLCγ1). PLCγ1 is a central signal transducer of growth factor and cytokine signaling pathways that are involved in tumorigenesis. In STAT3 Y705F mutant colorectal cancer cells, PLCγ1 activity is reduced. Moreover, overexpression of a constitutively active form of PLCγ1 rescues the transformation defect of STAT3 Y705F mutant cells. In aggregate, our study identifies previously unknown cross-talk between STAT3 and the PLCγ signaling pathways that may play a critical role in colorectal tumorigenesis.
Collapse
Affiliation(s)
- Peng Zhang
- Department of Genetics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-7285, USA
| | | | | | | | | | | |
Collapse
|
58
|
Winter N, Nimzyk R, Bösche C, Meyer A, Bullerdiek J. Chromatin immunoprecipitation to analyze DNA binding sites of HMGA2. PLoS One 2011; 6:e18837. [PMID: 21533145 PMCID: PMC3077414 DOI: 10.1371/journal.pone.0018837] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 03/21/2011] [Indexed: 12/17/2022] Open
Abstract
Background HMGA2 is an architectonic transcription factor abundantly expressed during embryonic and fetal development and it is associated with the progression of malignant tumors. The protein harbours three basically charged DNA binding domains and an acidic protein binding C-terminal domain. DNA binding induces changes of DNA conformation and hence results in global overall change of gene expression patterns. Recently, using a PCR-based SELEX (Systematic Evolution of Ligands by Exponential Enrichment) procedure two consensus sequences for HMGA2 binding have been identified. Methodology/Principal Findings In this investigation chromatin immunoprecipitation (ChIP) experiments and bioinformatic methods were used to analyze if these binding sequences can be verified on chromatin of living cells as well. Conclusion After quantification of HMGA2 protein in different cell lines the colon cancer derived cell line HCT116 was chosen for further ChIP experiments because of its 3.4-fold higher HMGA2 protein level. 49 DNA fragments were obtained by ChIP. These fragments containing HMGA2 binding sites have been analyzed for their AT-content, location in the human genome and similarities to sequences generated by a SELEX study. The sequences show a significantly higher AT-content than the average of the human genome. The artificially generated SELEX sequences and short BLAST alignments (11 and 12 bp) of the ChIP fragments from living cells show similarities in their organization. The flanking regions are AT-rich, whereas a lower conservation is present in the center of the sequences.
Collapse
Affiliation(s)
- Nina Winter
- Centre for Human Genetics, University of Bremen, Bremen, Germany
| | - Rolf Nimzyk
- Centre for Human Genetics, University of Bremen, Bremen, Germany
| | - Carolin Bösche
- Centre for Human Genetics, University of Bremen, Bremen, Germany
| | - Anke Meyer
- Centre for Human Genetics, University of Bremen, Bremen, Germany
| | - Jörn Bullerdiek
- Centre for Human Genetics, University of Bremen, Bremen, Germany
- Clinic for Small Animals and Research Cluster REBIRTH, University of Veterinary Medicine, Hannover, Germany
- * E-mail:
| |
Collapse
|
59
|
Yu HG, Nam JO, Miller NLG, Tanjoni I, Walsh C, Shi L, Kim L, Chen XL, Tomar A, Lim ST, Schlaepfer DD. p190RhoGEF (Rgnef) promotes colon carcinoma tumor progression via interaction with focal adhesion kinase. Cancer Res 2011; 71:360-70. [PMID: 21224360 DOI: 10.1158/0008-5472.can-10-2894] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Focal adhesion kinase (FAK) functions downstream of integrins and growth factor receptors to promote tumor cell motility and invasion. In colorectal cancer, FAK is activated by amidated gastrin, a protumorigenic hormone. However, it is unclear how FAK receives signals from the gastrin receptor or other G-protein-coupled receptors that can promote cell motility and invasion. The Rho guanine-nucleotide exchange factor p190RhoGEF (Rgnef) binds FAK and facilitates fibroblast focal adhesion formation on fibronectin. Here we report that Rgnef mRNA and protein expression are significantly increased during colorectal tumor progression. In human colon carcinoma cells, Rgnef forms a complex with FAK and upon gastrin stimulation, FAK translocates to newly-forming focal adhesions where it facilitates tyrosine phosphorylation of paxillin. short hairpin (shRNA)-mediated knockdown of Rgnef or FAK, or pharmacological inhibition of FAK activity, is sufficient to block gastrin-stimulated paxillin phosphorylation, cell motility, and invadopodia formation in a manner dependent upon upstream cholecystokinin-2 receptor expression. Overexpression of the C-terminal region of Rgnef (Rgnef-C, amino acid 1,279-1,582) but not Rgnef-CΔFAK (amino acid 1,302-1,582 lacking the FAK binding site) disrupted endogenous Rgnef-FAK interaction and prevented paxillin phosphorylation and cell motility stimulated by gastrin. Rgnef-C-expressing cells formed smaller, less invasive tumors with reduced tyrosine phosphorylation of paxillin upon orthotopic implantation, compared with Rgnef-CΔFAK-expressing cells. Our studies identify Rgnef as a novel regulator of colon carcinoma motility and invasion, and they show that a Rgnef-FAK linkage promotes colon carcinoma progression in vivo.
Collapse
Affiliation(s)
- Hong-Gang Yu
- Department of Reproductive Medicine, Moores Cancer Center, UCSD, La Jolla, California 92093, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
60
|
Abstract
Members of the protein tyrosine phosphatase (Ptp) family dephosphorylate target proteins and counter the activities of protein tyrosine kinases that are involved in cellular phosphorylation and signalling. As such, certain PTPs might be tumour suppressors. Indeed, PTPs play an important part in the inhibition or control of growth, but accumulating evidence indicates that some PTPs may exert oncogenic functions. Recent large-scale genetic analyses of various human tumours have highlighted the relevance of PTPs either as putative tumour suppressors or as candidate oncoproteins. Progress in understanding the regulation and function of PTPs has provided insights into which PTPs might be potential therapeutic targets in human cancer.
Collapse
Affiliation(s)
- Sofi G Julien
- Goodman Cancer Research Centre, Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | | | | | | |
Collapse
|
61
|
Du Z, Song J, Wang Y, Zhao Y, Guda K, Yang S, Kao HY, Xu Y, Willis J, Markowitz SD, Sedwick D, Ewing RM, Wang Z. DNMT1 stability is regulated by proteins coordinating deubiquitination and acetylation-driven ubiquitination. Sci Signal 2010; 3:ra80. [PMID: 21045206 DOI: 10.1126/scisignal.2001462] [Citation(s) in RCA: 250] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
DNA methyltransferase 1 (DNMT1) is the primary enzyme that maintains DNA methylation. We describe a previously unknown mode of regulation of DNMT1 protein stability through the coordinated action of an array of DNMT1-associated proteins. DNMT1 was destabilized by acetylation by the acetyltransferase Tip60, which triggered ubiquitination by the E3 ligase UHRF1, thereby targeting DNMT1 for proteasomal degradation. In contrast, DNMT1 was stabilized by histone deacetylase 1 (HDAC1) and the deubiquitinase HAUSP (herpes virus-associated ubiquitin-specific protease). Analysis of the abundance of DNMT1 and Tip60, as well as the association between HAUSP and DNMT1, suggested that during the cell cycle the initiation of DNMT1 degradation was coordinated with the end of DNA replication and the need for DNMT activity. In human colon cancers, the abundance of DNMT1 correlated with that of HAUSP. HAUSP knockdown rendered colon cancer cells more sensitive to killing by HDAC inhibitors both in tissue culture and in tumor xenograft models. Thus, these studies provide a mechanism-based rationale for the development of HDAC and HAUSP inhibitors for combined use in cancer therapy.
Collapse
Affiliation(s)
- Zhanwen Du
- Department of Genetics, Case Western Reserve University, Cleveland, OH 44106, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
62
|
Dudley JT, Chen R, Butte AJ. Matching cancer genomes to established cell lines for personalized oncology. PACIFIC SYMPOSIUM ON BIOCOMPUTING. PACIFIC SYMPOSIUM ON BIOCOMPUTING 2010:243-52. [PMID: 21121052 DOI: 10.1142/9789814335058_0026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The diagnosis and treatment of cancers, which rank among the leading causes of mortality in developed nations, presents substantial clinical challenges. The genetic and epigenetic heterogeneity of tumors can lead to differential response to therapy and gross disparities in patient outcomes, even for tumors originating from similar tissues. High-throughput DNA sequencing technologies hold promise to improve the diagnosis and treatment of cancers through efficient and economical profiling of complete tumor genomes, paving the way for approaches to personalized oncology that consider the unique genetic composition of the patient's tumor. Here we present a novel method to leverage the information provided by cancer genome sequencing to match an individual tumor genome with commercial cell lines, which might be leveraged as clinical surrogates to inform prognosis or therapeutic strategy. We evaluate the method using a published lung cancer genome and genetic profiles of commercial cancer cell lines. The results support the general plausibility of this matching approach, thereby offering a first step in translational bioinformatics approaches to personalized oncology using established cancer cell lines.
Collapse
Affiliation(s)
- Joel T Dudley
- Training Program in Biomedical Informatics, Stanford, CA 94305, USA
| | | | | |
Collapse
|
63
|
Zhang P, Becka S, Craig SEL, Lodowski DT, Brady-Kalnay SM, Wang Z. Cancer-derived mutations in the fibronectin III repeats of PTPRT/PTPrho inhibit cell-cell aggregation. ACTA ACUST UNITED AC 2010; 16:146-53. [PMID: 20230342 DOI: 10.3109/15419061003653771] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract The receptor protein tyrosine phosphatase T PTPrho is the most frequently mutated tyrosine phosphatase in human cancer. PTPrho mediates homophilic cell-cell aggregation. In its extracellular region, PTPrho has cell adhesion molecule-like motifs, including a MAM domain, an immunoglobulin domain, and four fibronectin type III (FNIII) repeats. Tumor-derived mutations have been identified in all of these extracellular domains. Previously, the authors determined that tumor-derived mutations in the MAM and immunoglobulin domains of PTPrho reduce homophilic cell-cell aggregation. In this paper, the authors describe experiments in which the contribution of the FNIII repeats to PTPrho-mediated cell-cell adhesion was evaluated. The results demonstrate that deletion of the FNIII repeats of PTPrho result in defective cell-cell aggregation. Furthermore, all of the tumor-derived mutations in the FNIII repeats of PTPrho also disrupt cell-cell aggregation. These results further support the hypothesis that mutational inactivation of PTPrho may lead to cancer progression by disrupting cell-cell adhesion.
Collapse
Affiliation(s)
- Peng Zhang
- Department of Genetics, Case Western Reserve University, Cleveland, Ohio 44106, USA
| | | | | | | | | | | |
Collapse
|