Dissecting the pathogenesis of classical Hodgkin lymphoma (cHL), a common cancer in young adults, remains challenging because of the rarity of tumor cells in involved tissues (usually <5%). Here, we analyzed the coding genome of cHL by microdissecting tumor and normal cells from 34 patient biopsies for a total of ∼50 000 singly isolated lymphoma cells. We uncovered several recurrently mutated genes, namely,

The goal of this study was to investigate the anti-cancer effects of Trans10,cis12 conjugated linoleic acid (t10,c12 CLA). MTT assays and QCM™ chemotaxis 96-wells were used to test the effect of t10,c12 CLA on the proliferation and migration and invasion of cancer cells. qPCR and Western Blotting were used to determine the expression of specific factors. RNA sequencing was conducted using the Illumina platform and apoptosis was measured using a flow cytometry assay. t10,c12 CLA (IC50, 7 μM) inhibited proliferation of ovarian cancer cell lines SKOV-3 and A2780. c9,t11 CLA did not attenuate the proliferation of these cells. Transcription of 165 genes was significantly repressed and 28 genes were elevated. Genes related to ER stress, ATF4, CHOP, and GADD34 were overexpressed whereas EDEM2 and Hsp90, genes required for proteasomal degradation of misfolded proteins, were downregulated upon treatment. While apoptosis was not detected, t10,c12 CLA treatment led to 9-fold increase in autophagolysosomes and higher levels of LC3-II. G1 cell cycle arrest in treated cells was correlated with phosphorylation of GSK3β and loss of β-catenin. microRNA miR184 and miR215 were upregulated. miR184 likely contributed to G1 arrest by downregulating E2F1. miR215 upregulation was correlated with increased expression of p27/Kip-1. t10,c12 CLA-mediated inhibition of invasion and migration correlated with decreased expression of PTP1b and decreased Src activation by inhibiting phosphorylation at Tyr416. Due to its ability to inhibit proliferation and migration, t10,c12 CLA should be considered for treatment of ovarian cancer.

Histone deacetylase 6 (HDAC6) plays an important role in oncogenic transformation and cancer metastasis. Our previous study has demonstrated that HDAC6 was highly expressed in melanoma cells, and contributed to the proliferation and metastasis of melanoma cells. However, the underlying mechanism of HDAC6 in melanoma metastasis and progression remains largely unclear. In this study, we reported that HDAC6 directly interacted with Tyrosine-protein phosphatase non-receptor type 1 (PTPN1) by performing co-immunoprecipitation (Co-IP) combined with liquid chromatography tandem mass spectrometry (LC-MS/MS). HDAC6 increased the protein level of PTPN1 independent of histone modifying activity. In addition, PTPN1 promoted proliferation, colony formation and migration while decreased apoptosis of melanoma cells through activating extracellular signal-regulated kinase 1/2 (ERK1/2). Furthermore, we found that matrix metallopeptidase 9 (MMP9) was increased by HDAC6/PTPN1/ERK1/2 axis, which might serve as a mechanism for melanoma invasion and metastasis. In conclusion, HDAC6 might enhance aggressive melanoma cells progression via interacting with PTPN1, which was independent of its histone modifying activity.

The strength and duration of STAT3 signaling are tightly controlled by multiple negative feedback mechanisms under physical conditions. However, how these serial feedback loops are simultaneously disrupted in cancers, leading to constitutive activation of STAT3 signaling in hepatocellular carcinoma (HCC), remains obscure. Here we report that miR-589-5p is elevated in HCC tissues, which is caused by recurrent gains. Overexpression of miR-589-5p correlates with poor overall and relapse-free survival in HCC patients. Upregulating miR-589-5p enhances spheroid formation ability, fraction of CD133 positive and side population cells, expression of cancer stem cell factors and the mitochondrial potential, and represses the apoptosis induced by doxorubicin in vitro and tumorigenicity in vivo in HCC cells; conversely, silencing miR-589-5p yields an opposite effect. Our findings further demonstrate miR-589-5p promotes the cancer stem cell characteristics and chemoresistance via targeting multiple negative regulators of STAT3 signaling pathway, including SOCS2, SOCS5, PTPN1 and PTPN11, leading to constitutive activation of STAT3 signaling. Collectively, our results unravel a novel mechanism by which miR-589-5p promotes the maintenance of stemness and chemoresistance in HCC, providing a potential rational registry of anti-miR-589-5p combining with conventional chemotherapy against HCC.

Triple-negative breast cancer is an aggressive form of breast cancer with few therapeutic options if it recurs after adjuvant chemotherapy. RNA interference could be an alternative therapy for metastatic breast cancer, where small interfering RNA (siRNA) can silence the expression of aberrant genes critical for growth and migration of malignant cells. Here, we formulated a siRNA delivery system using lipid-substituted polyethylenimine (PEI) and hyaluronic acid (HA), and characterized the size, ζ-potential and cellular uptake of the nanoparticulate delivery system. Higher cellular uptake of siRNA by the tailored PEI/HA formulation suggested better interaction of complexes with breast cancer cells due to improved physicochemical characteristics of carrier and HA-binding CD44 receptors. The siRNAs against specific phosphatases that inhibited migration of MDA-MB-231 cells were then identified using library screen against 267 protein-tyrosine phosphatases, and siRNAs to inhibit cell migration were further validated. We then assessed the combinational delivery of a siRNA against CDC20 to decrease cell growth and a siRNA against several phosphatases shown to decrease migration of breast cancer cells. Combinational siRNA therapy against CDC20 and identified phosphatases PPP1R7, PTPN1, PTPN22, LHPP, PPP1R12A and DUPD1 successfully inhibited cell growth and migration, respectively, without interfering the functional effect of the co-delivered siRNA. The identified phosphatases could serve as potential targets to inhibit migration of highly aggressive metastatic breast cancer cells. Combinational siRNA delivery against cell cycle and phosphatases could be a promising strategy to inhibit both growth and migration of metastatic breast cancer cells, and potentially other types of metastatic cancer.
STATEMENT OF SIGNIFICANCE: The manuscript investigated the efficacy of a tailored polymeric siRNA delivery system formulation as well as combinational siRNA therapy in metastatic breast cancer cells to inhibit malignant cell growth and migration. The siRNA delivery was undertaken by non-viral means with PEI/HA. We identified six phosphatases that could be critical targets to inhibit migration of highly aggressive metastatic breast cancer cells. We further report on specifically targeting cell cycle and phosphatase proteins to decrease both malignant cell growth and migration simultaneously. Clinical gene therapy against metastatic breast cancer with effective and safe delivery systems is urgently needed to realize the potential of molecular medicine in this deadly disease and our studies in this manuscript is intended to facilitate this endeavor.

Cellular senescence prevents the proliferation of cells at risk for neoplastic transformation. However, the altered secretome of senescent cells can promote the growth of the surrounding cancer cells. Although extracellular vesicles (EVs) have emerged as new players in intercellular communication, their role in the function of senescent cell secretome has been largely unexplored. Here, we show that exosome-like small EVs (sEVs) are important mediators of the pro-tumorigenic function of senescent cells. sEV-associated EphA2 secreted from senescent cells binds to ephrin-A1, that is, highly expressed in several types of cancer cells and promotes cell proliferation through EphA2/ephrin-A1 reverse signalling. sEV sorting of EphA2 is increased in senescent cells because of its enhanced phosphorylation resulting from oxidative inactivation of PTP1B phosphatase. Our results demonstrate a novel mechanism of reactive oxygen species (ROS)-regulated cargo sorting into sEVs, which is critical for the potentially deleterious growth-promoting effect of the senescent cell secretome.

The protein tyrosine phosphatase 1B (PTP1B) is an important regulator of metabolism. The relationship between PTP1B and tumors is quite complex. The purpose of this study is to explore the expression pattern and role of PTP1B in breast cancer. The expression of PTP1B was detected in 67 samples of breast cancer tissue by Western blot. Cell growth assay, Transwell migration assay, and Scratch motility assay were used to examine the proliferation and migration of MCF-7 with and without PTP1B. The total levels and phosphorylated levels of signal transduction and activator of transcription 3 (STAT3) and the expression of C-C motif chemokine ligand 5 (CCL5) were also examined by Western blot. PTP1B was overexpressed in over 70% of breast cancer tissues, correlating with patients with estrogen receptor (ER)-negative, progesterone receptor (PR)-negative, and human epidermal growth factor receptor 2 (HER2)-positive tumors. The data also showed that both tumor size and lymph node metastasis were significantly higher in patients with a higher level of PTP1B. The proliferation and migration of MCF-7 cells were found to be inhibited after knocking down the gene of PTP1B. Our data also showed that PTP1B could up-regulate the dephosphorylated level of STAT3, which could increase the expression of CCL5. These phenomena indicated that PTP1B may play a crucial role in the development of breast cancer.

OBJECTIVE: This case-control study investigated the association of single nucleotide polymorphisms in the PTPN1 gene with susceptibility to esophageal squamous cell carcinoma (ESCC) in Inner Mongolia, China.
METHODS: A total of 302 patients living in Inner Mongolia China who were pathologically diagnosed with ESCC between April 2012 and 2016 were selected for the ESCC group; 373 healthy individuals were selected for the control group. The rs2904268 C>G, rs2230605 A>G, and rs16995309 C>T polymorphisms in the PTPN1 gene were detected by bidirectional polymerase chain reaction amplification of specific alleles. The haplotype frequencies were analyzed by SHEsis software. Binary logistic regression analysis was conducted to analyze risk factors associated with ESCC.
RESULTS: Statistical differences between the ESCC and control groups were observed for history of smoking, drinking, and poor eating habits (all p < 0.05). Both the rs2904268 C>G CG and GG genotype frequencies were markedly higher in the ESCC group relative to the control group (both p < 0.05). However, the genotype frequencies of rs2230605 A>G and rs16995309 C>T were similar between the ESCC and control groups (all p > 0.05). Compared with the control group, the ESCC group had notably elevated frequencies of the GGC and GAT haplotypes and significantly reduced frequencies of CGC and GGT haplotypes (all p < 0.05). A history of smoking, drinking, poor eating habits, the rs2904268 C>G CG+GG genotypes, and the GAT haplotype were all identified as risk factors for ESCC (all p < 0.05).
CONCLUSION: These results indicated that the PTPN1 gene polymorphism rs2904268 is associated with susceptibility to ESCC in Inner Mongolia.

Target-specific next-generation sequencing technology was used to analyze 112 genes in adult patients with acute lymphoblastic leukemia (ALL). This sequencing mainly focused on the specific mutational hotspots. Among the 121 patients, 93 patients were B-ALL (76.9%), and 28 patients (23.1%) were T-ALL. Of the 121 patients, 110 (90.9%) harbored at least one mutation. The five most frequently mutated genes in T-ALL are NOTCH1, JAK3, FBXW7, FAT1, and NRAS. In B-ALL, FAT1, SF1, CRLF2, TET2, and PTPN1 have higher incidence of mutations. Gene mutations are different between Ph

Protein tyrosine phosphatase 1B (PTP1B) is known to promote the pathogenesis of diabetes and obesity by negatively regulating insulin and leptin pathways, but its role associated with colon carcinogenesis is still under debate. In this study, we demonstrated the oncogenic role of PTP1B in promoting colon carcinogenesis and predicting worse clinical outcomes in CRC patients. By co-immunoprecipitation, we showed that PITX1 was a novel substrate of PTP1B. Through direct dephosphorylation at Y160, Y175 and Y179, PTP1B destabilized PITX1, which resulted in downregulation of the PITX1/p120RasGAP axis. Interestingly, we found that regorafenib, the approved target agent for advanced CRC patients, exerted a novel property against PTP1B. By inhibiting PTP1B activity, regorafenib treatment augmented the stability of PITX1 protein and upregulated the expression of p120RasGAP in CRC. Importantly, we found that this PTP1B-dependant PITX1/p120RasGAP axis determines the in vitro anti-CRC effects of regorafenib. The above-mentioned effects of regorafenib were confirmed by the HT-29 xenograft tumor model. In conclusion, we demonstrated a novel oncogenic mechanism of PTP1B on affecting PITX1/p120RasGAP in CRC. Regorafenib inhibited CRC survival through reserving PTP1B-dependant PITX1/p120RasGAP downregulation. PTP1B may be a potential biomarker predicting regorafenib effectiveness, and a potential solution for CRC.

Metastasis is a complicated, multistep process and remains the major cause of cancer-related mortality. Exploring the molecular mechanisms underlying tumor metastasis is crucial for development of new strategies for cancer prevention and treatment. In this study, we found that protein tyrosine phosphatase 1B (PTP1B) promoted breast cancer metastasis by regulating phosphatase and tensin homolog (PTEN) but not epithelial-mesenchymal transition (EMT). By detecting PTP1B expression of the specimens from 128 breast cancer cases, we found that the level of PTP1B was higher in breast cancer tissues than the corresponding adjacent normal tissues. Notably, PTP1B was positively associated with lymph node metastasis (LNM) and estrogen receptor (ER) status. In vitro, disturbing PTP1B expression obviously attenuated cell migration and invasion. On the contrary, PTP1B overexpression significantly increased migration and invasion of breast cancer cells. Mechanistically, PTP1B knockdown upregulated PTEN, accompanied with an abatement of AKT phosphorylation and the expression of matrix metalloproteinase 2 (MMP2) and MMP7. Conversely, forced expression of PTP1B reduced PTEN and increased AKT phosphorylation as well as the expression of MMP2 and MMP7. Notably, neither EMT nor stemness of breast cancer cells was regulated by PTP1B. We also found that PTP1B acted as an independent prognostic factor and predicted poor prognosis in ER-positive breast cancer patients. Taken together, our findings provide advantageous evidence for the development of PTP1B as a potential therapeutic target for breast cancer, especially for ER-positive breast cancer patients.

BACKGROUND: Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer and frequently progresses from an actinic keratosis (AK), a sun-induced keratinocyte intraepithelial neoplasia (KIN). Epigenetic mechanisms involved in the phenomenon of progression from AK to cSCC remain to be elicited.
METHODS: Expression of microRNAs in sun-exposed skin, AK and cSCC was analysed by Agilent microarrays. DNA methylation of miR-204 promoter was determined by bisulphite treatment and pyrosequencing. Identification of miR-204 targets and pathways was accomplished in HaCat cells. Immunofluorescence and immunohistochemistry were used to analyze STAT3 activation and PTPN11 expression in human biopsies.
RESULTS: cSCCs display a marked downregulation of miR-204 expression when compared to AK. DNA methylation of miR-204 promoter was identified as one of the repressive mechanisms that accounts for miR-204 silencing in cSCC. In HaCaT cells miR-204 inhibits STAT3 and favours the MAPK signaling pathway, likely acting through PTPN11, a nuclear tyrosine phosphatase that is a direct miR-204 target. In non-peritumoral AK lesions, activated STAT3, as detected by pY705-STAT3 immunofluorescence, is retained in the membrane and cytoplasm compartments, whereas AK lesions adjacent to cSCCs display activated STAT3 in the nuclei.
CONCLUSIONS: Our data suggest that miR-204 may act as a "rheostat" that controls the signalling towards the MAPK pathway or the STAT3 pathway in the progression from AK to cSCC.

Tumours exist in a hypoxic microenvironment and must limit excessive oxygen consumption. Hypoxia-inducible factor (HIF) controls mitochondrial oxygen consumption, but how/if tumours regulate non-mitochondrial oxygen consumption (NMOC) is unknown. Protein-tyrosine phosphatase-1B (PTP1B) is required for Her2/Neu-driven breast cancer (BC) in mice, although the underlying mechanism and human relevance remain unclear. We found that PTP1B-deficient HER2(+) xenografts have increased hypoxia, necrosis and impaired growth. In vitro, PTP1B deficiency sensitizes HER2(+) BC lines to hypoxia by increasing NMOC by α-KG-dependent dioxygenases (α-KGDDs). The moyamoya disease gene product RNF213, an E3 ligase, is negatively regulated by PTP1B in HER2(+) BC cells. RNF213 knockdown reverses the effects of PTP1B deficiency on α-KGDDs, NMOC and hypoxia-induced death of HER2(+) BC cells, and partially restores tumorigenicity. We conclude that PTP1B acts via RNF213 to suppress α-KGDD activity and NMOC. This PTP1B/RNF213/α-KGDD pathway is critical for survival of HER2(+) BC, and possibly other malignancies, in the hypoxic tumour microenvironment.

Phosphatases are key regulators of cellular signaling and as such play an important role in nearly all cellular processes governing diseases, including cancer. However, due to their highly conserved structure and highly charged and reactive catalytic site, they have been regarded as "undruggable." Fortunately, during the recent Europhosphatase meeting (Turku, Finland), it became clear that phosphatases can no longer be ignored as potential targets in cancer therapy. As reactivation of tumor-suppressor phosphatases or direct inhibition of phosphatases acting as oncogenes is becoming available, this class of enzymes can now be considered as feasible drug targets. Cancer Res; 76(2); 193-6. ©2016 AACR.

UNLABELLED: The effective therapeutic targets for hepatocellular carcinoma remain limited. Pituitary homeobox 1 (PITX1) functions as a tumor suppressor in hepatocarcinogenesis by regulating the expression level of Ras guanosine triphosphatase-activating protein. Here, we report that protein tyrosine phosphatases 1B (PTP1B) directly dephosphorylated PITX1 at Y160, Y175, and Y179 to further weaken the protein stability of PITX. The PTP1B-dependent decline of PITX1 reduced its transcriptional activity for p120RasGAP (RASA1), a Ras guanosine triphosphatase-activating protein. Both silencing of PTP1B and PTP1B inhibitor up-regulated the PITX1-p120RasGAP axis through hyperphosphorylation of PITX1. Sorafenib, the first and only targeted drug approved for hepatocellular carcinoma, directly decreased PTP1B activity and promoted the expression of PITX1 and p120RasGAP by PITX1 hyperphosphorylation. Molecular docking also supported the potential interaction between PTP1B and sorafenib. PTP1B overexpression impaired the sensitivity of sorafenib in vitro and in vivo, implying that PTP1B has a significant effect on sorafenib-induced apoptosis. In sorafenib-treated tumor samples, we further found inhibition of PTP1B activity and up-regulation of the PITX1-p120RasGAP axis, suggesting that PTP1B inhibitor may be effective for the treatment of hepatocellular carcinoma. By immunohistochemical staining of hepatic tumor tissue from 155 patients, the expression of PTP1B was significantly in tumor parts higher than nontumor parts (P = 0.02). Furthermore, high expression of PTP1B was significantly associated with poor tumor differentiation (P = 0.031).
CONCLUSION: PTP1B dephosphorylates PITX1 to weaken its protein stability and the transcriptional activity for p120RasGAP gene expression and acts as a determinant of the sorafenib-mediated drug effect; targeting the PITX1-p120RasGAP axis with a PTP1B inhibitor may provide a new therapy for patients with hepatocellular carcinoma.

Lymphoid malignancies are characterized by an accumulation of genetic lesions that act co-operatively to perturb signaling pathways and alter gene expression programs. The Janus kinases (JAK)-signal transducers and activators of transcription (STATs) pathway is one such pathway that is frequently mutated in leukemia and lymphoma. In response to cytokines and growth factors, a cascade of reversible tyrosine phosphorylation events propagates the JAK-STAT pathway from the cell surface to the nucleus. Activated STAT family members then play a fundamental role in establishing the transcriptional landscape of the cell. In leukemia and lymphoma, somatic mutations have been identified in JAK and STAT family members, as well as, negative regulators of the pathway. Most recently, inactivating mutations in the protein tyrosine phosphatase (PTP) genes PTPN1 (PTP1B) and PTPN2 (TC-PTP) were sequenced in B cell lymphoma and T cell acute lymphoblastic leukemia (T-ALL) respectively. The loss of PTP1B and TC-PTP phosphatase activity is associated with an increase in cytokine sensitivity, elevated JAK-STAT signaling, and changes in gene expression. As inactivation mutations in PTPN1 and PTPN2 are restricted to distinct subsets of leukemia and lymphoma, a future challenge will be to identify in which cellular contexts do they contributing to the initiation or maintenance of leukemogenesis or lymphomagenesis. As well, the molecular mechanisms by which PTP1B and TC-PTP loss co-operates with other genetic aberrations will need to be elucidated to design more effective therapeutic strategies.

Though patient sex influences response to cancer treatments, little is known of the molecular causes, and cancer therapies are generally given irrespective of patient sex. We assessed transcriptomic differences in tumors from men and women spanning 17 cancer types, and we assessed differential expression between tumor and normal samples stratified by sex across 7 cancers. We used the LincsCloud platform to perform Connectivity Map analyses to link transcriptomic signatures identified in male and female tumors with chemical and genetic perturbagens, and we performed permutation testing to identify perturbagens that showed significantly differential connectivity with male and female tumors. Our analyses predicted that females are sensitive and males are resistant to tamoxifen treatment of lung adenocarcinoma, a finding which is consistent with known male-female differences in lung cancer. We made several novel predictions, including that CDK1 and PTPN1 knockdown would be more effective in males with hepatocellular carcinoma, and SMAD3 and HSPA4 knockdown would be more effective in females with head and neck squamous cell carcinoma. Our results provide a new resource for researchers studying male-female biological and treatment response differences in human cancer. The complete results of our analyses are provided at the website accompanying this manuscript (http://becklab.github.io/SexLinked).

Primary mediastinal B-Cell lymphoma (PMBL) is a recently defined entity comprising ~2-10% non-Hodgkin lymphomas (NHL). Unlike most NHL subtypes, PMBL lacks recurrent gene rearrangements to serve as biomarkers or betray target genes. While druggable, late chemotherapeutic complications warrant the search for new targets and models. Well characterized tumor cell lines provide unlimited material to serve as preclinical resources for verifiable analyses directed at the discovery of new biomarkers and pathological targets using high throughput microarray technologies. The same cells may then be used to seek intelligent therapies directed at clinically validated targets. Four cell lines have emerged as potential PMBL models: FARAGE, KARPAS-1106P, MEDB-1 and U-2940. Transcriptionally, PMBL cell lines cluster near c(lassical)-HL and B-NHL examples showing they are related but separate entities. Here we document genomic alterations therein, by cytogenetics and high density oligonucleotide/SNP microarrays and parse their impact by integrated global expression profiling. PMBL cell lines were distinguished by moderate chromosome rearrangement levels undercutting cHL, while lacking oncogene translocations seen in B-NHL. In total 61 deletions were shared by two or more cell lines, together with 12 amplifications (≥4x) and 72 homozygous regions. Integrated genomic and transcriptional profiling showed deletions to be the most important class of chromosome rearrangement. Lesions were mapped to several loci associated with PMBL, e.g. 2p15 (REL/COMMD1), 9p24 (JAK2, CD274), 16p13 (SOCS1, LITAF, CIITA); plus new or tenuously associated loci: 2p16 (MSH6), 6q23 (TNFAIP3), 9p22 (CDKN2A/B), 20p12 (PTPN1). Discrete homozygous regions sometimes substituted focal deletions accompanied by gene silencing implying a role for epigenetic or mutational inactivation. Genomic amplifications increasing gene expression or gene-activating rearrangements were respectively rare or absent. Our findings highlight biallelic deletions as a major class of chromosomal lesion in PMBL cell lines, while endorsing the latter as preclinical models for hunting and testing new biomarkers and actionable targets.

After allogeneic stem-cell transplantation, nonhematopoietic tissues contain donor-derived cells; however, whether cells from malignant hematological disease can also be found in nonhematopoietic tissues is unclear. This report describes a juvenile myelomonocytic leukemia (JMML) case with a typical PTPN11 mutation (p.E76K) at different allele frequencies in the bone marrow mononuclear cells, buccal smear cells, and fingernails at diagnosis, which was suggestive of PTPN11 somatic mosaicism; however, the PTPN11 mutation in the buccal smear cells and fingernails was lost after unrelated cord blood transplantation. These results suggest that JMML-derived cells may migrate into and reside in nonhematopoietic tissues and furthermore that these cells can be eradicated by cord blood transplantation.

In order to study molecular similarities and differences of intrahepatic (IH-CCA) and extrahepatic (EH-CCA) cholangiocarcinoma, 24 FFPE tumor samples (13 IH-CCA, 11 EH-CCA) were analyzed for whole genome copy number variations (CNVs) using a new high-density Molecular Inversion Probe Single Nucleotide Polymorphism (MIP SNP) assay. Common in both tumor subtypes the most frequent losses were detected on chromosome 1p, 3p, 6q and 9 while gains were mostly seen in 1q, 8q as well as complete chromosome 17 and 20. Applying the statistical GISTIC (Genomic Identification of Significant Targets in Cancer) tool we identified potential novel candidate tumor suppressor- (DBC1, FHIT, PPP2R2A) and oncogenes (LYN, FGF19, GRB7, PTPN1) within these regions of chromosomal instability. Next to common aberrations in IH-CCA and EH-CCA, we additionally found significant differences in copy number variations on chromosome 3 and 14. Moreover, due to the fact that mutations in the Isocitrate dehydrogenase (IDH-1 and IDH-2) genes are more frequent in our IH-CCA than in our EH-CCA samples, we suggest that the tumor subtypes have a different molecular profile. In conclusion, new possible target genes within regions of high significant copy number aberrations were detected using a high-density Molecular Inversion Probe Single Nucleotide Polymorphism (MIP SNP) assay, which opens a future perspective of fast routine copy number and marker gene identification for gene targeted therapy.

Phosphoprotein enriched in astrocytes of 15 kDa (PEA-15) is known to sequester extracellular signal-regulated kinase (ERK) in the cytoplasm, inhibiting tumorigenesis of human breast cancer cells. Here, we describe how PEA-15 expression affects the dephosphorylation of epidermal growth factor receptor (EGFR) through endoplasmic reticulum (ER)-plasma membrane (PM) contacts in MDA-MB-468, triple-negative breast cancer (TNBC) cells. The increased intracellular calcium concentration resulting from increased cytoplasmic phosphorylated ERK facilitates movement of ER-anchored calcium sensors to the PM. The driving force of trans-localization of calcium-dependent proteins enhances the contact between the activated EGFR and ER-localized phosphatase, PTP1B. Consequently, our findings suggest a mechanism underneath the facilitation of EGFR dephosphorylation by cytoplasmic PEA-15 expression inside TNBC cells, which may be one of the dynamic mechanisms for down-regulation of activated EGFR in cancer cells.

The protein tyrosine phosphatase 1B (PTP1B), a non-transmembrane protein tyrosine phosphatase, has been implicated in gastric pathogenesis. Several lines of recent evidences have shown that PTP1B is highly amplified in breast and prostate cancers. The aim of this study was to investigate PTP1B amplification in gastric cancer and its association with poor prognosis of gastric cancer patients, and further determine the role of PTP1B in gastric tumorigenesis. Our data demonstrated that PTP1B was significantly up-regulated in gastric cancer tissues as compared with matched normal gastric tissues by using quantitative RT-PCR (qRT-PCR) assay. In addition, copy number analysis showed that PTP1B was amplified in 68/131 (51.9%) gastric cancer cases, whereas no amplification was found in the control subjects. Notably, PTP1B amplification was positively associated with its protein expression, and was significantly related to poor survival of gastric cancer patients. Knocking down PTP1B expression in gastric cancer cells significantly inhibited cell proliferation, colony formation, migration and invasion, and induced cell cycle arrested and apoptosis. Mechanically, PTP1B promotes gastric cancer cell proliferation, survival and invasiveness through modulating Src-related signaling pathways, such as Src/Ras/MAPK and Src/phosphatidylinositol-3-kinase (PI3K)/Akt pathways. Collectively, our data demonstrated frequent overexpression and amplification PTP1B in gastric cancer, and further determined the oncogenic role of PTP1B in gastric carcinogenesis. Importantly, PTP1B amplification predicts poor survival of gastric cancer patients.

PURPOSE: There is growing evidence for a role of proteinase-activated receptors (PARs), a subfamily of G protein-coupled receptors, in cancer. We have previously shown that PAR1 and PAR4 are able to promote the migration of hepatocellular carcinoma (HCC) cells suggesting a function in HCC progression. In this study, we assessed the underlying signalling mechanisms.
METHODS: Using Hep3B liver carcinoma cells, RTK activation was assessed by Western blot employing phospho-RTK specific antibodies, ROS level were estimated by H2DCF-DA using confocal laser scanning microscopy, and measurement of PTP activity was performed in cell lysates using 6,8-difluoro-4-methylumbelliferyl phosphate (DiFMUP) as a substrate.
RESULTS: Thrombin, the PAR1 selective agonist peptide TFLLRN-NH2 (PAR1-AP), and the PAR4 selective agonist peptide, AYPGKF-NH2 (PAR4-AP), induced a significant increase in Hep3B cell migration that could be blocked by inhibitors targeting formation of reactive oxygen species (ROS), or activation of hepatocyte-growth factor receptor (Met), or platelet-derived growth factor receptor (PDGFR), respectively. The involvement of these intracellular effectors in PAR1/4-initiated migratory signalling was further supported by the findings that individual stimulation of Hep3B cells with the PAR1-AP and the PAR4-AP induced an increase in ROS production and the transactivation of Met and PDGFR. In addition, PAR1- and PAR4-mediated inhibition of total PTP activity and specifically PTP1B. ROS inhibition by N-acetyl-L-cysteine prevented the inhibition of PTP1B phosphatase activity induced by PAR1-AP and the PAR4-AP, but had no effect on PAR1/4-mediated activation of Met and PDGFR in Hep3B cells.
CONCLUSIONS: Collectively, our data indicate that PAR1 and PAR4 activate common promigratory signalling pathways in Hep3B liver carcinoma cells including activation of the receptor tyrosine kinases Met and PDGFR, the formation of ROS and the inactivation of PTP1B. However, PAR1/4-triggered Met and PDGFR transactivation seem to be mediated independently from the ROS-PTP1B signalling module.

Aberrant expression and activation of FGFR3 is associated with disease states including bone dysplasia and malignancies of bladder, cervix, and bone marrow. MS analysis of protein-phosphotyrosine in multiple myeloma cells revealed a prevalent phosphorylated motif, D/EYYR/K, derived from the kinase domain activation loops of tyrosine kinases including FGFR3 corresponding to a recognition sequence of protein-tyrosine phosphatase PTPN1. Knockdown of PTPN1 or the related enzyme PTPN2 by RNAi resulted in ligand-independent activation of FGFR3. Modulation of FGFR3 activation loop phosphorylation by both PTPN1 and PTPN2 was a function of receptor trafficking and phosphotyrosine phosphatase (PTP) compartmentalization. The FGFR3 activation loop motif DYYKK(650) is altered to DYYKE(650) in the oncogenic variant FGFR3(K650E) , and consequently it is constitutively fully activated and unaffected by activation loop phosphorylation. FGFR3(K650E) was nevertheless remarkably sensitive to negative regulation by PTPN1 and PTPN2. This suggests that in addition to modulating FGFR3 phosphorylation, PTPN1 and PTPN2 constrain the kinase domain by fostering an inactive-state. Loss of this constraint in response to ligand or impaired PTPN1/N2 may initiate FGFR3 activation. These results suggest a model wherein PTP expression levels may define conditions that select for ectopic FGFR3 expression and activation during tumorigenesis.

PTP1B, a validated therapeutic target for diabetes and obesity, has a critical positive role in HER2 signaling in breast tumorigenesis. Efforts to develop therapeutic inhibitors of PTP1B have been frustrated by the chemical properties of the active site. We define a new mechanism of allosteric inhibition that targets the C-terminal, noncatalytic segment of PTP1B. We present what is to our knowledge the first ensemble structure of PTP1B containing this intrinsically disordered segment, within which we identified a binding site for the small-molecule inhibitor MSI-1436. We demonstrate binding to a second site close to the catalytic domain, with cooperative effects between the two sites locking PTP1B in an inactive state. MSI-1436 antagonized HER2 signaling, inhibited tumorigenesis in xenografts and abrogated metastasis in the NDL2 mouse model of breast cancer, validating inhibition of PTP1B as a therapeutic strategy in breast cancer. This new approach to inhibition of PTP1B emphasizes the potential of disordered segments of proteins as specific binding sites for therapeutic small molecules.

miR-210 is upregulated in a HIF-1α-dependent way in several types of cancers. In addition, upregulated miR-210 promotes cancer proliferation, via its anti-apoptotic effects. It is blind to the regulation of miR-210 under hypoxia conditions for ovarian cancer cells and to the effect of miR-210 on ovarian cancer growth. In the present study, we determined the expression of miR-210 in epithelial ovarian cancer specimens, and in ovarian cancer cell lines under hypoxia conditions, and determined in detail the effect of miR-210 overexpression on tumor cell proliferation, and the possible mechanisms of tumor growth by miR-210 regulation. It was shown that miR-210 expression is upregulated, in response to hypoxia conditions in epithelial ovarian cancer specimens as well as epithelial ovarian cancer cell lines, with an association to HIF-1α overexpression. Furthermore, upregulated miR-210 promoted tumor growth in vitro via targeting PTPN1 and inhibiting apoptosis. Therefore, our findings shed light on the mechanism of ovarian cancer adaptation to hypoxia.

Classical Hodgkin lymphoma and primary mediastinal B cell lymphoma (PMBCL) are related lymphomas sharing pathological, molecular and clinical characteristics. Here we discovered by whole-genome and whole-transcriptome sequencing recurrent somatic coding-sequence mutations in the PTPN1 gene. Mutations were found in 6 of 30 (20%) Hodgkin lymphoma cases, in 6 of 9 (67%) Hodgkin lymphoma-derived cell lines, in 17 of 77 (22%) PMBCL cases and in 1 of 3 (33%) PMBCL-derived cell lines, consisting of nonsense, missense and frameshift mutations. We demonstrate that PTPN1 mutations lead to reduced phosphatase activity and increased phosphorylation of JAK-STAT pathway members. Moreover, silencing of PTPN1 by RNA interference in Hodgkin lymphoma cell line KM-H2 resulted in hyperphosphorylation and overexpression of downstream oncogenic targets. Our data establish PTPN1 mutations as new drivers in lymphomagenesis.

Cortactin (CTTN), first identified as a major substrate of the Src tyrosine kinase, actively participates in branching F-actin assembly and in cell motility and invasion. CTTN gene is amplified and its protein is overexpressed in several types of cancer. The phosphorylated form of cortactin (pTyr(421)) is required for cancer cell motility and invasion. In this study, we demonstrate that a majority of the tested primary colorectal tumor specimens show greatly enhanced expression of pTyr(421)-CTTN, but no change at the mRNA level as compared to healthy subjects, thus suggesting post-translational activation rather than gene amplification in these tumors. Curcumin (diferulolylmethane), a natural compound with promising chemopreventive and chemosensitizing effects, reduced the indirect association of cortactin with the plasma membrane protein fraction in colon adenocarcinoma cells as measured by surface biotinylation, mass spectrometry, and Western blotting. Curcumin significantly decreased the pTyr(421)-CTTN in HCT116 cells and SW480 cells, but was ineffective in HT-29 cells. Curcumin physically interacted with PTPN1 tyrosine phosphatases to increase its activity and lead to dephosphorylation of pTyr(421)-CTTN. PTPN1 inhibition eliminated the effects of curcumin on pTyr(421)-CTTN. Transduction with adenovirally-encoded CTTN increased migration of HCT116, SW480, and HT-29. Curcumin decreased migration of HCT116 and SW480 cells which highly express PTPN1, but not of HT-29 cells with significantly reduced endogenous expression of PTPN1. Curcumin significantly reduced the physical interaction of CTTN and pTyr(421)-CTTN with p120 catenin (CTNND1). Collectively, these data suggest that curcumin is an activator of PTPN1 and can reduce cell motility in colon cancer via dephosphorylation of pTyr(421)-CTTN which could be exploited for novel therapeutic approaches in colon cancer therapy based on tumor pTyr(421)-CTTN expression.

Several genomic regions are frequently altered and associated with the type, stage and progression of urinary bladder cancer (UBC). We present the characterization of 5637, T24 and HT1376 UBC cell lines by karyotyping, fluorescence in situ hybridization (FISH), array comparative genomic hybridization (aCGH) and multiplex ligation-dependent probe amplification (MLPA) analysis. Some cytogenetic anomalies present in UBC were found in the three cell lines, such as chromosome 20 aneuploidy and the loss of 9p21. Some gene loci losses (e.g. CDKN2A) and gains (e.g. HRAS, BCL2L1 and PTPN1) were coincident across all cell lines. Although some significant heterogeneity and complexity were detected between them, their genomic profiles exhibited a similar pattern to UBC. We suggest that 5637 and HT1376 represent the E2F3/RB1 pathway due to amplification of 6p22.3, concomitant with loss of one copy of RB1 and mutation of the remaining copy. The HT1376 presented a 10q deletion involving PTEN region and no alteration of PIK3CA region which, in combination with the inactivation of TP53, bears more invasive and metastatic properties than 5637. The T24 belongs to the alternative pathway of FGFR3/CCND1 by presenting mutated HRAS and over-represented CCND1. These cell lines cover the more frequent subtypes of UBC and are reliable models that can be used, as a group, in preclinical studies.

UNLABELLED: Transforming growth factor (TGF)-β induces epithelial-mesenchymal transition (EMT) in pancreatic adenocarcinoma. In this study, we investigated how NADPH oxidase (Nox) 4-generated reactive oxygen species (ROS) regulate TGF-β-induced EMT in pancreatic cancer cells.
MATERIALS AND METHODS: Pancreatic cancer cells were transfected with Nox4 siRNAs or PTP1B mutants and subjected to TGF-β-induced EMT assay. Expression of Nox4, TGF-β, and N-cadherin was immunohistochemically-examined with patient tumor samples.
RESULTS: Treatment of pancreatic cancer cells with TGF-β induced Nox4 expression, indicating that Nox4 represents a major source for ROS production. The Nox4 inhibitor diphenylene iodonium and Nox4 siRNAs blocked TGF-β-induced EMT phenotype including morphological changes, augmented migration, and altered expression of E-cadherin and Snail. Furthermore, PTP1B as a redox-sensor for Nox4-derived ROS participated in TGF-β-promoted EMT. Nox4, TGF-β, and N-cadherin were up-regulated in tumors from pancreatic cancer patients.
CONCLUSIONS: These findings suggest that Nox4-derived ROS, at least in part, transmit TGF-β-triggered EMT signals through PTP1B in pancreatic cancer.