The function of the protein tyrosine phosphatase SHP-1 in cancer

Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worchester, MA 01605, USA.
Gene (Impact Factor: 2.14). 04/2003; 306(1):1-12. DOI: 10.1016/S0378-1119(03)00400-1
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ABSTRACT SHP-1, an SH2 domain-containing protein tyrosine phosphatase, is primarily expressed in hematopoietic cells and behaves as a key regulator controlling intracellular phosphotyrosine levels in lymphocytes. SHP-1 has been proposed as a candidate tumor suppressor gene in lymphoma, leukemia and other cancers, as it functions as an antagonist to the growth-promoting and oncogenic potentials of tyrosine kinase. The decreased levels of SHP-1 protein and SHP-1 mRNA observed in various leukemia and lymphoma cell lines have been attributed to either the methylation of the promoter region of the SHP-1 gene or the post-transcriptional block of SHP-1 protein synthesis. In contrast, SHP-1 protein is normally or over-expressed in some non-lymphocytic cell lines, such as prostate cancer, ovarian cancer and breast cancer cell lines. SHP-1 expression also is decreased in some breast cancer cell lines with negative expression of estrogen receptor as well as some prostate and colorectal cancer cell lines. These data suggest that SHP-1 can play either negative or positive roles in regulating signal transduction pathways. Dysfunction in SHP-1 regulation can cause abnormal cell growth and induce different kinds of cancers. In this paper, we summarize recent studies on the expression and regulation of SHP-1 protein and its pathological function in the development of lymphoma, leukemia and other cancers.

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Available from: Lijun Liu, Oct 02, 2014
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    • "SHP-1 is a non-transmembrane PTPase and predominantly expressed in hematopoietic cells [24]. It has been shown to be involved in the negative regulation of JAK/STAT signaling in leukemia and lymphoma [25]. "
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    ABSTRACT: Persistent activation of signal transducers and activator of transcription 3 (STAT3) has been closely related to growth, survival, proliferation, metastasis, and angiogenesis of various cancer cells, and thus its inhibition can be considered a potential therapeutic strategy. In this study, we investigated the role of bergamottin (BGM) obtained from grapefruit juice in abrogating the constitutive STAT3 activation in multiple myeloma (MM) cells. This suppression was mediated through the inhibition of phosphorylation of Janus-activated kinase (JAK) 1/2 and c-Src. Pervanadate reversed the BGM induced down-regulation of STAT3 activation, suggesting the involvement of a protein tyrosine phosphatase (PTP). Furthermore, BGM induced the expression of the tyrosine phosphatase SHP-1, and gene silencing of the SHP-1 by small interfering RNA abolished the ability of BGM to inhibit STAT3 activation, suggesting a critical role for SHP-1 in the action of BGM. BGM also downregulated the expression of STAT3-regulated gene products such as COX-2, VEGF, Cyclin D1, Survivin, IAP-1, Bcl-2, and Bcl-xl in MM cells. This correlated with induction of substantial apoptosis as indicated by an increase in the sub-G1 cell population and caspase-3 induced PARP cleavage. Also, this agent significantly potentiated the apoptotic effects of bortezomib and thalidomide in MM cells. Overall, these results suggest that BGM is a novel blocker of STAT3 activation pathway thus may have a potential in therapy of MM and other cancers.
    Cancer Letters 08/2014; 354(1). DOI:10.1016/j.canlet.2014.08.002 · 5.62 Impact Factor
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    • "Notably, in addition to phosphorylation of c-terminal tail, SHP-1 also forms an auto-inhibited structure between inhibitory N-SH2 domain and catalytic PTP domain to regulate the phosphatase activity. This intramolecular variability of SHP-1 structure determines the exposure of WPD loop containing active residue, Asp421, in catalytic PTP domain [16] [17] [18]. Importantly, the Asp residue at 61 (D61) in the N-SH2 domain is a major blockade of the WPD loop. "
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    ABSTRACT: Background & Aims Nintedanib, a triple angiokinase inhibitor, is currently being evaluated against advanced HCC in phase I/II clinical trials. Here, we report the underlying molecular mechanism by which nintedanib (BIBF-1120) induces an anti-HCC effect. Methods To further elucidate whether the effect of nintedanib on SHP-1 is dependent on its angiokinase inhibition activity, we developed a novel kinase-independent derivative of nintedanib, △N. HCC cell lines were treated with nintedanib or its derivative (△N) and apoptosis, signal transduction, and phosphatase activity were analyzed. Purified SHP-1 proteins or HCC cells expressing deletion N-SH2 domain or D61A point mutants were used to investigate the potential effect of nintedanib on SHP-1. In vivo efficacy was determined in nude mice with HCC subcutaneous xenografts (n ⩾ 8 mice). Results Nintedanib induced anti-proliferation in HCC cell lines by targeting STAT3. Ectopic STAT3 abolished nintedanib-mediated apoptosis in HCC cells. Nintedanib further activated SHP-1 in purified SHP-1 proteins suggesting that nintedanib directly affects SHP-1 for STAT3 inhibition. HCC cells or recombinant SHP-1 proteins expressing deletion of N-SH2 domain or D61A mutants restored the activity of nintedanib suggesting that the auto-inhibition structure of SHP-1 was relieved by nintedanib. Although △N only retained the backbone of nintedanib without kinase activity, △N still induced substantial anti-HCC activity in vitro and in vivo by targeting STAT3. Conclusions Nintedanib induced significant anti-HCC activity independent of angiokinase inhibition activity in a preclinical HCC model by relieving autoinhibition of SHP-1. Our findings provide new mechanistic insight into the inhibition of HCC growth by nintedanib.
    Journal of Hepatology 07/2014; 74(19 Supplement). DOI:10.1016/j.jhep.2014.03.017 · 11.34 Impact Factor
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    • "SHP-1, a members of the Src homology 2 (SH2)-domain containing tyrosine phosphatase family, is one of the protein tyrosine phosphatases that can deactivate STAT3 signaling through direct dephosphorylation of p-STAT3 (Tyr 705) [20] [21] [22]. In addition, SHP-1 is a negative regulator of several signaling pathways involved in cancers [23] [24], and it can be regulated by several transcription factors [25] [26]. RFX-1 is a transcription factor that has been reported to positively modulate SHP-1 expression in breast cancer [27]. "
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    ABSTRACT: Hepatocellular carcinoma is the fifth most common solid cancer worldwide. Sorafenib, a small multikinase inhibitor, is the only approved therapy for advanced HCC. The clinical benefit of sorafenib is offset by the acquisition of sorafenib resistance. Understanding of the molecular mechanism of STAT3 overexpression in sorafenib resistance is critical if the clinical benefits of this drug are to be improved. In this study, we explored our hypothesis that loss of RFX-1/SHP-1 and further increase of p-STAT3 as a result of sorafenib treatment induces sorafenib resistance as a cytoprotective response effect, thereby, limiting sorafenib sensitivity and efficiency. We found that knockdown of RFX-1 protected HCC cells against sorafenib-induced cell apoptosis and SHP-1 activity was required for the process. SC-2001, a molecule with similar structure to obatoclax, synergistically suppressed tumor growth when used in combination with sorafenib in vitro and overcame sorafenib resistance through up-regulating RFX-1 and SHP-1 resulting in tumor suppression and mediation of dephosphorylation of STAT3. In addition, sustained sorafenib treatment in HCC led to increased p-STAT3 which was a key mediator of sorafenib sensitivity. The combination of SC-2001 and sorafenib strongly inhibited tumor growth in both wild-type and sorafenib-resistant HCC cell bearing xenograft models. These results demonstrate that inactivation of RFX/SHP-1 induced by sustained sorafenib treatment confers sorafenib resistance to HCC through p-STAT3 up-regulation. These effects can be overcome by SC-2001 through RFX-1/SHP-1 dependent p-STAT3 suppression. In conclusion, the use of SC-2001 in combination with sorafenib may constitute a new strategy for HCC therapy.
    Neoplasia (New York, N.Y.) 07/2014; 16(7). DOI:10.1016/j.neo.2014.06.005 · 4.25 Impact Factor
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