Upregulation of Src homology phosphotyrosyl phosphatase 2 (Shp2) expression in oral cancer and knockdown of Shp2 expression inhibit tumor cell viability and invasion in vitro

Effects of changes in SHP2 expression on liver fibrosis by influencing the apoptosis of hepatic stellate cells

Accumulating research has revealed that src-homology domain 2-containing protein tyrosine phosphatase-2 (SHP2), an oncogenic protein tyrosine phosphatase, is associated with liver fibrosis. Currently, it is still unclear whether SHP2 affects liver fibrosis by influencing the apoptosis of hepatic stellate cells (HSC). In present study, we investigate effects of SHP2 expression changes on liver fibrosis, with special emphasis on the apoptosis of HSC. Using adenovirus vector, wild-type SHP2 gene and short hairpin RNA targeting SHP2 were introduced into rats with liver fibrosis and LX-2 cells in vitro. The expressions of type I and III collagen, pathological and functional changes, collagen deposition in rat liver and apoptosis of LX-2 cells were detected by immunohistochemical and HE staining, automated biochemical analyzer, Masson trichrome staining, and TUNEL. This study showed that overexpression of SHP2 exacerbated dysfunction, inflammatory damage, collagen deposition and increased expression of type I and III collagen in rat liver reduced apoptosis of LX-2 cells. On the contrary, low expression of SHP2 alleviated the aforementioned detection indicators of rats and promoted apoptosis of LX-2 cells. In conclusion, the downregulation of SHP2 expression alleviates liver fibrosis by inducing the apoptosis of HSC, while overexpressed SHP2 exacerbates liver fibrosis by inhibiting the apoptosis of HSC.

TNO155 is a selective SHP2 inhibitor to target PTPN11-dependent oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is known to be driven by multiple intricated receptor tyrosine kinases (RTKs) including EGFR, PI3K/AKT and MAPK signaling pathways. However, whilst targeting EGFR with cetuximab has been approved for the treatment of OSCC, other single-agent inhibitors of the RTKs have shown modest effects in improving survival. From the genome-wide CRISPR/Cas9 screen on 21 OSCC cell lines, we have identified PTPN11 among the top essential genes in OSCC. PTPN11 encodes for SHP2, a phosphatase that acts as a master signal transducer, downstream of various RTKs. Although PTPN11 overexpression has been reported in OSCC, little is known about its role as an essential gene for OSCC survival and its potential as a therapeutic target. Herein, we confirmed that PTPN11 is an essential gene in OSCC where its deletion significantly impacted cell survival. We evaluated three SHP2 inhibitors on 21 OSCC cell lines and found TNO155 to be significantly associated with CRISPR dependency score. We showed that TNO155 caused dose-dependent suppression on p-ERK and p-MEK, and suppresses the JAK/STAT pathway via downregulating p-JAK1, p-STAT1, p-STAT3. Furthermore, we confirmed that the combination of the mTOR inhibitor, everolimus with TNO155 is synergistic in OSCC. In summary, PTPN11 is a promising therapeutic target in OSCC that can be selectively targeted by SHP2 inhibitor such as TNO155. Our findings on the use of mTOR inhibitor, everolimus to overcome resistance to TNO155 are essential to inform on next phases of clinical trials which is warranted for the treatment of OSCC.

Tyrosine phosphatase PTPN11/SHP2 in solid tumors - bull's eye for targeted therapy?

Encoded by PTPN11, the Src-homology 2 domain-containing phosphatase 2 (SHP2) integrates signals from various membrane-bound receptors such as receptor tyrosine kinases (RTKs), cytokine and integrin receptors and thereby promotes cell survival and proliferation. Activating mutations in the PTPN11 gene may trigger signaling pathways leading to the development of hematological malignancies, but are rarely found in solid tumors. Yet, aberrant SHP2 expression or activation has implications in the development, progression and metastasis of many solid tumor entities. SHP2 is involved in multiple signaling cascades, including the RAS-RAF-MEK-ERK-, PI3K-AKT-, JAK-STAT- and PD-L1/PD-1- pathways. Although not mutated, activation or functional requirement of SHP2 appears to play a relevant and context-dependent dichotomous role. This mostly tumor-promoting and infrequently tumor-suppressive role exists in many cancers such as gastrointestinal tumors, pancreatic, liver and lung cancer, gynecological entities, head and neck cancers, prostate cancer, glioblastoma and melanoma. Recent studies have identified SHP2 as a potential biomarker for the prognosis of some solid tumors. Based on promising preclinical work and the advent of orally available allosteric SHP2-inhibitors early clinical trials are currently investigating SHP2-directed approaches in various solid tumors, either as a single agent or in combination regimes. We here provide a brief overview of the molecular functions of SHP2 and collate current knowledge with regard to the significance of SHP2 expression and function in different solid tumor entities, including cells in their microenvironment, immune escape and therapy resistance. In the context of the present landscape of clinical trials with allosteric SHP2-inhibitors we discuss the multitude of opportunities but also limitations of a strategy targeting this non-receptor protein tyrosine phosphatase for treatment of solid tumors.

High expression of SHP2 predicts a promising prognosis in colorectal cancer

Background

Src homology 2 domain-containing phosphatase 2 (SHP2) is hyper-activated in some solid tumors. Previous findings suggest that the expression of SHP2 in colorectal cancer (CRC) may be associated with prognosis. However, validation with large sample data is lacking. Materials and Methods: Tissue microarrays containing 860 CRCs and 197 mucosal tissues adjacent to the tumors were constructed. Immunohistochemistry was used to evaluate the expression of SHP2. Differences between SHP2 expression and clinicopathological parameters were evaluated. Kaplan-Meier survival curves and log-rank tests were used to analyze the relationships between SHP2 expression and the overall survival of patients. A Cox proportional hazard regression model was used for univariate and multivariate analyses of prognostic factors.

Results

SHP2 expression in CRCs tissues was significantly higher than those in adjacent mucosal tissues (P < 0.001). SHP2 expression was related to tumor differentiation, depth of invasion, distant metastasis, vascular tumor thrombus, lymph node metastasis, and TNM classification (P < 0.05). The prognosis of the high-expression group of SHP2 was significantly better than that of the low-expression group (P = 0.008). Univariate analysis showed that the expression of SHP2 was a prognostic factor for CRC (P = 0.008). Multivariate analysis demonstrated that SHP2 remained an independent prognostic factor for CRC (P = 0.033).

Conclusion

The expression of SHP2 was significantly higher in CRC tissues than in adjacent normal tissues. High expression of SHP2 was associated with a promising outcome, suggesting that SHP2 may be a favorable prognostic indicator of CRC.

SHP2 potentiates anti-PD-1 effectiveness through intervening cell pyroptosis resistance in triple-negative breast cancer

Triple negative breast cancer (TNBC) presents a formidable challenge due to the lack of effective treatment modalities. Immunotherapy stands as a promising therapeutic approach; however, the emergence of drug resistance mechanisms within tumor cells, particularly those targeting apoptosis and pyroptosis, has hampered its clinical efficacy. SHP2 is intricately involved in diverse physiological processes, including immune cell proliferation, infiltration, and tumor progression. Nevertheless, the precise contribution of SHP2 to tumor cell pyroptosis resistance remains inadequately understood. Herein, we demonstrate that SHP2 inhibition hampers the proliferative, migratory, and invasive capabilities of TNBC, accompanied by noticeable alterations in cellular membrane architecture. Mechanistically, we provide evidence that SHP2 depletion triggers the activation of Caspase-1 and GSDMD, resulting in GSDMD-dependent release of LDH, IL-1β, and IL-18. Furthermore, computational analyses and co-localization investigations substantiate the hypothesis that SHP2 may hinder pyroptosis through direct binding to JNK, thereby impeding JNK phosphorylation. Our cellular experiments further corroborate these findings by demonstrating that JNK inhibition rescues pyroptosis induced by SHP2 knockdown. Strikingly, in vivo experiments validate the suppressive impact of SHP2 knockdown on tumor progression via enhanced JNK phosphorylation. Additionally, SHP2 knockdown augments tumor sensitivity to anti-PD-1 therapy, thus reinforcing the pro-pyroptotic effects and inhibiting tumor growth. In summary, our findings elucidate the mechanism by which SHP2 governs TNBC pyroptosis, underscoring the potential of SHP2 inhibition to suppress cell pyroptosis resistance and its utility as an adjunctive agent for tumor immunotherapy.

New insights into RAS in head and neck cancer

RAS genes are known to be dysregulated in cancer for several decades, and substantial effort has been dedicated to develop agents that reduce RAS expression or block RAS activation. The recent introduction of RAS inhibitors for cancer patients highlights the importance of comprehending RAS alterations in head and neck cancer (HNC). In this regard, we examine the published findings on RAS alterations and pathway activations in HNC, and summarize their role in HNC initiation, progression, and metastasis. Specifically, we focus on the intrinsic role of mutated-RAS on tumor cell signaling and its extrinsic role in determining tumor-microenvironment (TME) heterogeneity, including promoting angiogenesis and enhancing immune escape. Lastly, we summarize the intrinsic and extrinsic role of RAS alterations on therapy resistance to outline the potential of targeting RAS using a single agent or in combination with other therapeutic agents for HNC patients with RAS-activated tumors.

Mometasone Furoate Inhibits the Progression of Head and Neck Squamous Cell Carcinoma via Regulating Protein Tyrosine Phosphatase Non-Receptor Type 11

Mometasone furoate (MF) is a kind of glucocorticoid with extensive pharmacological actions, including inhibiting tumor progression; however, the role of MF in head and neck squamous cell carcinoma (HNSCC) is still unclear. This study aimed to evaluate the inhibitory effect of MF against HNSCC and investigate its underlying mechanisms. Cell viability, colony formation, cell cycle and cell apoptosis were analyzed to explore the effect of MF on HNSCC cells. A xenograft study model was used to investigate the effect of MF on HNSCC in vivo. The core targets of MF for HNSCC were identified using network pharmacology analysis, TCGA database analysis and real-time PCR. Molecular docking was performed to determine the binding energy. Protein tyrosine phosphatase non-receptor type 11 (PTPN11)-overexpressing cells were constructed, and then, the cell viability and the expression levels of proliferation- and apoptosis-related proteins were detected after treatment with MF to explore the role of PTPN11 in the inhibitory effect of MF against HNSCC. After cells were treated with MF, cell viability and the number of colonies were decreased, the cell cycle was arrested and cell apoptosis was increased. The xenograft study results showed that MF could inhibit cell proliferation via promoting cell apoptosis in vivo. PTPN11 was shown to be the core target of MF against HNSCC via network pharmacology analysis, TCGA database analysis and real-time PCR. The molecular docking results revealed that PTPN11 exhibited the strongest ability to bind to MF. Finally, MF could attenuate the effects of increased cell viability and decreased cell apoptosis caused by PTPN11 overexpression, suggesting that MF can inhibit the progression of HNSCC by regulating PTPN11. MF targeted PTPN11, promoting cell cycle arrest and cell apoptosis, and consequently exerting effective anti-tumor activity.

Deregulation of hsa_circ_0001971/miR-186 and hsa_circ_0001874/miR-296 signaling pathways promotes the proliferation of oral squamous carcinoma cells by synergistically activating SHP2/PLK1 signals

It has been demonstrated that circ_0001874 and circ_0001971 are potential biomarkers for the diagnosis of oral squamous carcinoma (OSCC). MiR-186 was reported to serve as a tumor suppressor in OSCC, and the down-regulation of miR-186 was reported to lead to higher expression of oncogenic factor SHP2 and the activation of growth promoting signaling. In this study, we aimed to explore the possible molecular role of circ_0001874 and circ_0001971 signaling in the pathogenesis of OSCC. RT-qPCR, Western blot, online bioinformatics tools and luciferase assay were utilized to study the molecular signaling pathways of circ_0001874 and circ_0001971. MTT assay and FCM assay were performed to investigate the synergistic effect of circ_0001971 and circ_0001874 on cell proliferation and apoptosis. By observing the effect of different miRNAs on the levels of circ_0001847 and circ_0001971, it was identified that circ_0001847 and circ_0001971 respectively sponged the expression of miR-296 and miR-186 via binding to these miRNAs. Also, SHP2 mRNA and PLK1 mRNA were respectively targeted by miR-186 and miR-296-5p. We also established two signaling pathways, i.e., circ_0001971/miR-186/SHP2 and circ_0001874/miR-296-5p/PLK1, and validated the synergistic effect of circ_0001971 and circ_0001874 via observing their positive effect on cell proliferation and negative effect on cell apoptosis. The expression of miR-186 and miR-296-5p was generally lower in saliva of OSCC patients compared with that in OLK patients, while the expression of miR-186 and miR-296-5p was specifically up-regulated in saliva of OSCC patients. In conclusion, the finding of this study demonstrated that the relative level of hsa_circ_0001971 and hsa_circ_0001874 were different in the saliva of OSCC patients and could be used as predictive biomarkers for the development of OSCC. Furthermore, oncogenic effects of hsa_circ_0001971 and hsa_circ_0001874 in the development of OSCC might be, at least partially, mediated by its downstream signaling pathways including hsa_circ_0001971/microRNA-186/SHP2 and hsa_circ_0001874/microRNA-297/PLK1.

Grass carp (Ctenopharyngodon idellus) SHP2 suppresses IFN I expression via decreasing the phosphorylation of GSK3β in a non-contact manner

As a tyrosine phosphatase, Src homology 2-containing protein tyrosine phosphatase 2 (SHP2) serves as an inhibitor in PI3K-Akt pathway. In mammals, SHP2 can phosphorylate GSK3β at Y216 site to control the expression of IFN. So far, the multiple functions of SHP2 have been reported in mammals. However, little is known about fish SHP2. In this study, we cloned and identified a grass carp (Ctenopharyngodon idellus) SHP2 gene (CiSHP2, MT373151). SHP2 is conserved among different vertebrates by amino acid sequences alignment and the phylogenetic tree analysis. CiSHP2 shared the closest homology with Danio rerio SHP2. Simultaneously, SHP2 was also tested in grass carp tissues and CIK (C. idellus kidney) cells. We found that it responded to poly I:C stimulation. CiSHP2 was located in the cytoplasm just as the same as those of mammals. Interestingly, it inhibited the phosphorylation level of GSK3β in a non-contact manner. Meanwhile CiGSK3β interacted with and directly phosphorylated CiTBK1. In addition, we found that CiSHP2 also reduced the phosphorylation level of CiTBK1 by CiGSK3β, and then it depressed the expression of IFN I via GSK3β-TBK1 axis. These results suggested that CiSHP2 was involved in CiGSK3β and CiTBK1 activity but not regulated their transcriptional level. At the same time, we also found that CiSHP2 also influenced the activity of CiIRF3. Therefore, fish SHP2 inhibited IFN I expression through blocking GSK3β-TBK1 signal axis.

Role of Protein Tyrosine Phosphatase in Regulation of Cell Signaling Cascades Affecting Tumor Cell Growth: A Future Perspective as Anti- Cancer Drug Target

Protein Tyrosine Phosphatase (PTP) superfamily is a key enzyme involved in the regulation of growth-related cell signaling cascades, such as the RAS/MAPK pathway, that directly affect cancer cell growth and metastasis. Several studies have indicated that the drug resistance observed in several late-stage tumors might also be affected by the levels of PTP in the cell. Hence, these phosphatases have been in the limelight for the past few decades as potential drug-targets and several promising drug candidates have been developed, even though none of these drugs have reached the market yet. In this review, we explore the potential of PTP as a viable anti-cancer drug target by studying PTPs, their regulation of several key cancer cell signaling pathways and how their levels affect various types of cancer. Furthermore, we present the current scenario of PTP as a molecular target and the various challenges faced in the development of PTP-targeting anti-cancer drugs.

The tyrosine phosphatase SHP-2 dephosphorylated by ALV-J via its Env efficiently promotes ALV-J replication

Avian leukosis virus subgroup J (ALV-J) generally induces hemangioma, myeloid leukosis, and immunosuppression in chickens, causing significant poultry industry economic losses worldwide. The unusual env gene of ALV-J, with low homology to other subgroups of ALVs, is associated with its unique pathogenesis. However, the exact molecular basis for the pathogenesis and oncogenesis of ALV-J is still not fully understood. In this study, ALV-J infection and the overexpression of Env could efficiently downregulate the phosphorylation of SHP-2 (pSHP-2) in vitro and in vivo. The membrane-spanning domain (MSD) in Env Gp37 was the functional domain responsible for pSHP-2 downregulation. Moreover, the overexpression of SHP-2 could effectively promote the replication of ALV-J, whereas knockout or allosteric inhibition of SHP-2 could inhibit ALV-J replication. In addition, the knockout of endogenous chicken SHP-2 could significantly increase the proliferation ability of DF-1 cells. All these data demonstrate that SHP-2 dephosphorylated by ALV-J Env could efficiently promote ALV-J replication, highlighting the important role of SHP-2 in the pathogenesis of ALV-J and providing a new target for developing antiviral drugs against ALV-J.

Targeting SHP2 as a therapeutic strategy for inflammatory diseases

With the change of lifestyle and the acceleration of aging process, inflammatory diseases have increasingly become one of the most vital threats to global human health. SHP2 protein is a non-receptor tyrosine phosphatase encoded by PTPN11 gene, and it is widely expressed in various tissues and cells. Numerous studies have shown that SHP2 plays important roles in the regulation of inflammatory diseases, including cancer-related inflammation, neurodegenerative diseases and metabolic diseases. In this paper, the roles of SHP2 in inflammatory diseases of various physiological systems were reviewed. At the same time, the latest SHP2 inhibitors were summarized, which will hold a promise for the therapeutic potential in future.

Inhibitor Binding Sites in the Protein Tyrosine Phosphatase SHP-2

Protein tyrosine phosphatase 2 (SHP-2) has long been proposed as a cancer drug target. Several small-molecule compounds with different mechanisms of SHP-2 inhibition have been reported, but none are commercially available. Pool selectivity over protein tyrosine phosphatase 1 (SHP-1) and a lack of cellular activity have hindered the development of selective SHP-2 inhibitors. In this review, we describe the binding modes of existing inhibitors and SHP-2 binding sites, summarize the characteristics of the sites involved in selectivity, and identify the suitable groups for interaction with the binding sites.

Oncogenic Tyrosine Phosphatases: Novel Therapeutic Targets for Melanoma Treatment

Despite a large number of therapeutic options available, malignant melanoma remains a highly fatal disease, especially in its metastatic forms. The oncogenic role of protein tyrosine phosphatases (PTPs) is becoming increasingly clear, paving the way for novel antitumor treatments based on their inhibition. In this review, we present the oncogenic PTPs contributing to melanoma progression and we provide, where available, a description of new inhibitory strategies designed against these enzymes and possibly useful in melanoma treatment. Considering the relevance of the immune infiltrate in supporting melanoma progression, we also focus on the role of PTPs in modulating immune cell activity, identifying interesting therapeutic options that may support the currently applied immunomodulating approaches. Collectively, this information highlights the value of going further in the development of new strategies targeting oncogenic PTPs to improve the efficacy of melanoma treatment.

A Ce(iii) complex potently inhibits the activity and expression of tyrosine phosphatase SHP-2

Four new Ce(iii) complexes 1-4 with tridentate NNO-donor Schiff base ligands have been designed and successfully synthesized. These complexes were characterized by elemental analysis, IR, and ESI-MS, with formulas of [Ce(HL1)2(NO3)3]·2CH3OH (1), [Ce(L2)2(NO3)]·3H2O (2), [Ce(HL3)(L3)(NO3)Br]·H2O (3) and [Ce(L4)2(NO3)]·3H2O (4), in which ligands HL1-HL4 are respectively N'-[(1E)-pyridin-2-ylmethylidene]pyrazine-2-carbohydrazide (HL1), 2-(1-(salicyloylhydrazono)ethyl)pyrazine (HL2), N'-[(1E)-pyridin-2-ylmethylidene]pyridine-2-carbohydrazide (HL3) and 2-(1-(salicyloylhydrazono)ethyl) pyridine (HL4). X-ray single crystal diffraction analysis indicates that complex 1 crystallizes in the monoclinic system with the space group C2/c and the structure of complex 1 consists of a monomeric Ce(iii) species with a Ce(iii) moiety bonded to two tridentate Schiff base ligands, three nitrates and solvents. These complexes effectively inhibit the enzyme activities of PTPs (SHP-1, SHP-2, TCPTP and PTP1B), among which complex 3 shows the most potent inhibition of SHP-2 with the lowest IC50 value of 0.61 μM and displays obvious selectivity towards SHP-2. Its inhibition potency against SHP-2 was approximately 17, 4, and 5 fold higher than that against SHP-1, TCPTP and PTP1B, respectively. Further study discloses that complex 3 inhibits SHP-2 in a competitive manner. Fluorescence measurements indicate that complex 3 tightly binds to SHP-2 with a molar ratio of 1 : 1 and a binding constant of 5.45 × 105 M-1. Western blot experiments show that complex 3 promotes the phosphorylation of the SHP-2 substrate by the combination of the inhibition of the activity and expression of SHP-2. Moreover, complex 3 decreases the survival rate of A549 cells to 35.12% at 100 μM and induces apoptosis with an apoptosis rate of 12.06% at 50 μM. All these results suggest that complex 3 is a potential bi-functional inhibitor of the activity and expression of tyrosine phosphatase SHP-2.

Shp2 expression is upregulated in cervical cancer, and Shp2 contributes to cell growth and migration and reduces sensitivity to cisplatin in cervical cancer cells

Src homology phosphotyrosine phosphatase 2 (Shp2) has been found to be overexpressed in cervical cancer tissues. However, the influence of Shp2 on the biological behavior and sensitivity to cisplatin of cervical cancer cells remains unclear. We aimed to assess Shp2 expression in cervical tissues and cell lines and to detect the influence of Shp2 knockdown and overexpression on the biological behavior and sensitivity to cisplatin in cervical cancer cells. We found that Shp2 expression was significantly upregulated in cervical cancer tissues and cell lines, and Shp2 overexpression was associated with lymph node metastasis and a high human papillomavirus (HPV) DNA load. Shp2 knockdown inhibited cell growth and migration and enhanced sensitivity to cisplatin in the HeLa and SiHa cervical cancer cell lines. In contrast, Shp2 overexpression had the opposite effects. These tumor-promoting effects of Shp2 may be partly related to Akt signaling. In conclusion, Shp2 is involved in the occurrence and development of cervical cancer and may confer cisplatin resistance in cervical cancer. Shp2 blockade may be a new strategy for cervical cancer treatment.

Upregulation of eukaryotic translation initiation factor 3 subunit a promotes cell survival in ameloblastoma

OBJECTIVES

This study aimed to detect the expression of eukaryotic translation initiation factor 3 subunit a (eIF3a) in ameloblastoma (AB) tissues compared with normal oral mucosa (NOM) tissues and investigate the roles of eIF3a in the immortalized ameloblastoma cell line (AM-1) cell proliferation and apoptosis.

STUDY DESIGN

We performed immunohistochemistry to determine the expression of eIF3a in AB tissues (n = 83) and NOM tissues (n = 20). Real time-quantitative polymerase chain reaction and Western blot analyses were conducted with AB tissues (n = 30) and NOM tissues (n = 6). The correlation between eIF3a expression and the clinical/pathologic features of patients with AB is also presented. The functional role of eIF3a in AM-1 cells was assessed with lentiviral vector-mediated shRNA (small hairpin RNA).

RESULTS

Our results indicated that eIF3a was significantly upregulated in AB. Additionally, eIF3a knockdown in AM-1 cells significantly inhibited cell proliferation and promoted apoptosis.

CONCLUSIONS

These data indicate that eIF3a facilitates the survival of AB cells and may serve as a promising therapeutic target in AB.

Association of nuclear localization of SHP2 and YAP1 with unfavorable prognosis in non-small cell lung cancer

Src homology region 2 (SH2)-containing protein tyrosine phosphatase 2 (SHP2) is ubiquitously expressed in cytoplasmic localization, which in turn confers tumor malignancy and poor prognosis in various human cancers. YAP1 interacts with SHP2 to promote translocation of SHP2 to nucleus, which consequently promotes Wnt target activation. However, the oncogenic role of the nuclear localization of SHP2 in human cancers remains unclear. We hypothesized that nuclear SHP2 localization, in combination with nuclear YAP1 expression, could be associated with poor overall survival (OS) and relapse free survival (RFS) due to an increase in cyclin D1 and c-Myc mRNA expression following activation of Wnt/ß-catenin signaling. Immunohistochemical analysis of SHP2 and YAP1 protein expression in 102 tumors resected from patients with NSCLC revealed that nuclear SHP2 expression was well correlated with nuclear YAP1 expression (P < 0.001). Evaluation of cyclin D1 and c-Myc mRNA levels by the real-time reverse-phase polymerase chain reaction (RT-PCR) revealed that patients with high cyclin D1 and high c-Myc mRNA expressing tumors more commonly showed high nuclear YAP1 and high nuclear SHP2 (high/high) rather than the high/low, low/high, or low/low combinations (P < 0.001 for cyclin D1 and c-Myc). Kaplan-Meier and Cox-regression models showed OS and RFS to be poorer in patients in the high/high subgroup than in the low/low subgroup (OS: HR = 2.85, 95% CI, 1.52-5.35, P = 0.001; RFS: HR = 2.55, 95% CI, 1.37-4.72, P = 0.003). No prognostic significance was observed for the other two subgroups (low/high and high/low) when compared to the low/low subgroup in this study population. Therefore, we suggest that the prognostic value of SHP2 could reflect the nuclear localization of SHP2 and its interaction with nuclear YAP1, which led to subsequent upregulation of cyclin D1 and c-Myc mRNA expression via activation of the Wnt/ß-catenin signaling pathway.

Mechanism of activating mutations and allosteric drug inhibition of the phosphatase SHP2

Protein tyrosine phosphatase SHP2 functions as a key regulator of cell cycle control, and activating mutations cause several cancers. Here, we dissect the energy landscape of wild-type SHP2 and the oncogenic mutation E76K. NMR spectroscopy and X-ray crystallography reveal that wild-type SHP2 exchanges between closed, inactive and open, active conformations. E76K mutation shifts this equilibrium toward the open state. The previously unknown open conformation is characterized, including the active-site WPD loop in the inward and outward conformations. Binding of the allosteric inhibitor SHP099 to E76K mutant, despite much weaker, results in an identical structure as the wild-type complex. A conformational selection to the closed state reduces drug affinity which, combined with E76K’s much higher activity, demands significantly greater SHP099 concentrations to restore wild-type  activity levels. The differences in structural ensembles and drug-binding kinetics of cancer-associated SHP2 forms may stimulate innovative ideas for developing more potent inhibitors for activated SHP2 mutants.

The protein tyrosine phosphatase SHP2 is a key regulator of cell cycle control. Here the authors combine NMR measurements and X-ray crystallography and show that wild-type SHP2 dynamically exchanges between a closed inactive conformation and an open activated form and that the oncogenic E76K mutation shifts the equilibrium to the open state, which is reversed by binding of the allosteric inhibitor SHP099.

Shp2 Plays a Critical Role in IL-6-Induced EMT in Breast Cancer Cells

Accumulative evidence demonstrates that the protein tyrosine phosphatase Shp2 functions as a powerful tumor promoter in many types of cancers. Abnormal expression of Shp2 has been implicated in many human malignancies. Overexpression of Shp2 in cancer tissues is correlated with cancer metastasis, resistance to targeted therapy, and poor prognosis. The well-known function of Shp2 is its positive role in regulating cellular signaling initiated by growth factors and cytokines, including interleukin-6 (IL-6). Several recent studies have shown that Shp2 is required for epithelial-mesenchymal transition (EMT), triggered by growth factors. However, whether Shp2 is involved in IL-6-signaling-promoted breast cancer EMT and progression, remains undefined. In this study, we showed that exogenous and endogenous IL-6 can enhance breast cancer invasion and migration, through the promotion of EMT. IL-6 also induces the activation of Erk1/2 and the phosphorylation of Shp2. Knockdown of Shp2 attenuated the IL-6-induced downregulation of E-cadherin, as well as IL-6-promoted cell migration and invasion. Moreover, by using Shp2 phosphatase mutants, phosphor-tyrosine mimicking, and deficiency mutants, we provided evidence that the phosphatase activity of Shp2 and its tyrosine phosphorylation, are necessary for the IL-6-induced downregulation of E-cadherin and the phosphorylation of Erk1/2. Our findings uncover an important function that links Shp2 to IL-6-promoted breast cancer progression.

Discovery of a Novel Inhibitor of the Protein Tyrosine Phosphatase Shp2

Shp2 is a ubiquitously expressed protein tyrosine phosphatase (PTP) related to adult acute myelogenous leukemia and human solid tumors. In this report, we describe identification of a potent Shp2 inhibitor, Fumosorinone (Fumos) from entomogenous fungi, which shows selective inhibition of Shp2 over other tested PTPs. Using a surface plasmon resonance analysis, we further confirmed the physical interaction between Shp2 and Fumos. Fumos inhibits Shp2-dependent activation of the Ras/ERK signal pathway downstream of EGFR, and interrupts EGF-induced Gab1-Shp2 association. As expected, Fumos shows little effects on the Shp2-independent ERK1/2 activation induced by PMA or oncogenic Ras. Furthermore, Fumos down-regulates Src activation, inhibits phosphorylation of Paxillin and prevents tumor cell invasion. These results suggest that Fumos can inhibit Shp2-dependent cell signaling in human cells and has a potential for treatment of Shp2-associated diseases.

Functions of Shp2 in cancer

Diagnostics and therapies have shown evident advances. Tumour surgery, chemotherapy and radiotherapy are the main techniques in treat cancers. Targeted therapy and drug resistance are the main focus in cancer research, but many molecular intracellular mechanisms remain unknown. Src homology region 2-containing protein tyrosine phosphatase 2 (Shp2) is associated with breast cancer, leukaemia, lung cancer, liver cancer, gastric cancer, laryngeal cancer, oral cancer and other cancer types. Signalling pathways involving Shp2 have also been discovered. Shp2 is related to many diseases. Mutations in the ptpn11 gene cause Noonan syndrome, LEOPARD syndrome and childhood leukaemia. Shp2 is also involved in several cancer-related processes, including cancer cell invasion and metastasis, apoptosis, DNA damage, cell proliferation, cell cycle and drug resistance. Based on the structure and function of Shp2, scientists have investigated specific mechanisms involved in cancer. Shp2 may be a potential therapeutic target because this phosphatase is implicated in many aspects. Furthermore, Shp2 inhibitors have been used in experiments to develop treatment strategies. However, conflicting results related to Shp2 functions have been presented in the literature, and such results should be resolved in future studies.