The Phosphatase PTP-PEST/PTPN12 Regulates Endothelial Cell Migration and Adhesion, but Not Permeability, and Controls Vascular Development and Embryonic Viability

Newberg

Proc. Natl. Acad. Sci. U.S.A.

et al. 2016

Epithelial-mesenchymal transition (EMT) is thought to contribute to metastasis and chemoresistance in patients with hepatocellular carcinoma (HCC), leading to their poor prognosis. The genes driving EMT in HCC are not yet fully understood, however. Here, we show that mobilization of Sleeping Beauty (SB) transposons in immortalized mouse hepatoblasts induces mesenchymal liver tumors on transplantation to nude mice. These tumors show significant down-regulation of epithelial markers, along with up-regulation of mesenchymal markers and EMT-related transcription factors (EMTTFs). Sequencing of transposon insertion sites from tumors identified 233 candidate cancer genes (CCGs) that were enriched for genes and cellular processes driving EMT. Subsequent trunk driver analysis identified 23 CCGs that are predicted to function early in tumorigenesis and whose mutation or alteration in patients with HCC is correlated with poor patient survival. Validation of the top trunk drivers identified in the screen, including MET (MET proto-oncogene, receptor tyrosine kinase), GRB2-associated binding protein 1 (GAB1), HECT, UBA, and WWE domain containing 1 (HUWE1), lysine-specific demethylase 6A (KDM6A), and protein-tyrosine phosphatase, nonreceptor-type 12 (PTPN12), showed that deregulation of these genes activates an EMT program in human HCC cells that enhances tumor cell migration. Finally, deregulation of these genes in human HCC was found to confer sorafenib resistance through apoptotic tolerance and reduced proliferation, consistent with recent studies showing that EMT contributes to the chemoresistance of tumor cells. Our unique cell-based transposon mutagenesis screen appears to be an excellent resource for discovering genes involved in EMT in human HCC and potentially for identifying new drug targets.H CC is the sixth most common cancer and the third-leading cause of cancer-related deaths worldwide (1). In the United States, the incidence of HCC is increasing, and overall 5-y survival is now <12%, despite recent progress in diagnostic and therapeutic modalities (2). This high mortality rate is related mainly to a high recurrence rate and associated intrahepatic or extrahepatic metastases (1). Patients with HCC who develop metastasis are no longer eligible for liver transplantation therapy and have very limited therapeutic options. Currently, sorafenib is the sole systemic antineoplastic agent for HCC described in the National Comprehensive Cancer Network (NCCN) guideline (3); however, its clinical benefit is limited (4), and alternative effective treatments are needed for these patients.Epithelial-mesenchymal transition (EMT) is a complex differentiation process whereby epithelial cells lose their identity and acquire mesenchymal characteristics (5). EMT is observed routinely in developmental processes, but is also believed to play an important role in the migration, invasion, and metastasis of various cancers (6-9). It also promotes the generation of cancer stem cells, thereby contributing to tumor recurrence and metastasis...

Section: Discussionmentioning

confidence: 99%

Transposon mutagenesis identifies genes and cellular processes driving epithelial-mesenchymal transition in hepatocellular carcinoma

Newberg

Proc. Natl. Acad. Sci. U.S.A.

et al. 2016

Journal of Biological Chemistry

“…Two mechanisms regulate the activation of Pyk2; the first, direct one, that leads to its initial autophosphorylation, is Ca 2ϩ -dependent, and the second involves dephosphorylation by various phosphatases (49), the tyrosine phosphatase PTP-PEST being a prime example. Regu- lation of Pyk2 by PTP-PEST has been described in a number of non-neuronal cellular contexts (29,50), and PTP-PEST has been shown to control dendritic arborization (52) by dephosphorylating Pyk2 and other proteins of the focal adhesion complex. PTP-PEST affects the phosphorylation status of a large set of proteins (53), and therefore, it is conceivable that PTP-PEST contributes an additional and currently unknown layer of complexity to fast CORT-triggered signaling pathways.…”

Section: Discussionmentioning

confidence: 99%

Non-receptor-tyrosine Kinases Integrate Fast Glucocorticoid Signaling in Hippocampal Neurons

Yang

Roselli

Patchev

et al. 2013

Background: The intracellular signaling cascades through which corticosterone rapidly alters neuronal activity are poorly defined. Results: Corticosterone alters glutamatergic transmission by activating diverse GPCR-dependent signaling pathways. Conclusion: Corticosterone-induced changes in neuronal excitability are initiated at the plasma membrane. Significance: The sequential recruitment and integration of diverse signaling cascades by corticosterone adds to the understanding of how steroids rapidly alter neuronal function.

Molecular and Cellular Biology

“…It belongs to the PEST family, with PTPN22 and PTPN8 (3). PTPN12 can dephosphorylate several proteins, such as Cas, focal adhesion kinase (FAK), Pyk2, paxillin, Shc, and receptor protein tyrosine kinases (PTKs), and can regulate multiple cellular processes, including migration, adhesion, and receptortriggered proliferation (6)(7)(8)(9)(10)(11)(12).…”

mentioning

confidence: 99%

Control of Dendritic Cell Migration, T Cell-Dependent Immunity, and Autoimmunity by Protein Tyrosine Phosphatase PTPN12 Expressed in Dendritic Cells

Rhee

Zhong

Reizis

et al. 2014

Self Cite

f Dendritic cells (DCs) capture and process antigens in peripheral tissues, migrate to lymphoid tissues, and present the antigens to T cells. PTPN12, also known as PTP-PEST, is an intracellular protein tyrosine phosphatase (PTP) involved in cell-cell and cellsubstratum interactions. Herein, we examined the role of PTPN12 in DCs, using a genetically engineered mouse lacking PTPN12 in DCs. Our data indicated that PTPN12 was not necessary for DC differentiation, DC maturation, or cytokine production in response to inflammatory stimuli. However, it was needed for full induction of T cell-dependent immune responses in vivo. This function largely correlated with the need of PTPN12 for DC migration from peripheral sites to secondary lymphoid tissues. Loss of PTPN12 in DCs resulted in hyperphosphorylation of the protein tyrosine kinase Pyk2 and its substrate, the adaptor paxillin. Pharmacological inhibition of Pyk2 or downregulation of Pyk2 expression also compromised DC migration, suggesting that Pyk2 deregulation played a pivotal role in the migration defect caused by PTPN12 deficiency. Together, these findings identified PTPN12 as a key regulator in the ability of DCs to induce antigen-induced T cell responses. This is due primarily to the role of PTPN12 in DC migration from peripheral sites to secondary lymphoid organs through regulation of Pyk2.