Gene Summary

Gene:PTPRK; protein tyrosine phosphatase receptor type K
Aliases: R-PTP-kappa
Summary:The protein encoded by this gene is a member of the protein tyrosine phosphatase (PTP) family. PTPs are known to be signaling molecules that regulate a variety of cellular processes including cell growth, differentiation, mitotic cycle, and oncogenic transformation. This PTP possesses an extracellular region, a single transmembrane region, and two tandem catalytic domains, and thus represents a receptor-type PTP. The extracellular region contains a meprin-A5 antigen-PTP mu (MAM) domain, an Ig-like domain and four fibronectin type III-like repeats. This PTP was shown to mediate homophilic intercellular interaction, possibly through the interaction with beta- and gamma-catenin at adherens junctions. Expression of this gene was found to be stimulated by TGF-beta 1, which may be important for the inhibition of keratinocyte proliferation. [provided by RefSeq, Jul 2008]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:receptor-type tyrosine-protein phosphatase kappa
Source:NCBIAccessed: 31 August, 2019


What does this gene/protein do?
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Cancer Overview

Research Indicators

Publications Per Year (1994-2019)
Graph generated 01 September 2019 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 31 August, 2019 using data from PubMed, MeSH and CancerIndex

Specific Cancers (5)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: PTPRK (cancer-related)

Świerczewska M, Sterzyńska K, Wojtowicz K, et al.
PTPRK Expression Is Downregulated in Drug Resistant Ovarian Cancer Cell Lines, and Especially in ALDH1A1 Positive CSCs-Like Populations.
Int J Mol Sci. 2019; 20(8) [PubMed] Free Access to Full Article Related Publications

Xu X, Li D, Liu J, et al.
Downregulation of PTPRK Promotes Cell Proliferation and Metastasis of NSCLC by Enhancing STAT3 Activation.
Anal Cell Pathol (Amst). 2019; 2019:4265040 [PubMed] Free Access to Full Article Related Publications
Objective: The receptor-type tyrosine-protein phosphatase
Methods: PTPRK expression in NSCLC tissues and cell lines was examined using real-time PCR and western blotting. In addition, the effects of PTPRK on cell migration, invasion, and proliferation were evaluated
Results: The results showed that PTPRK expression was frequently reduced in NSCLC tissues with lymph node metastasis and cell lines. The inhibition of PTPRK expression resulted in increased proliferation, invasion, and migration of NSCLC cells
Conclusions: These results suggested that PTPRK functions as a novel tumor suppressor in NSCLC, and its suppressive ability may be involved in STAT3 activation.

Wang Y, Yang Z, Wang L, et al.
miR-532-3p promotes hepatocellular carcinoma progression by targeting PTPRT.
Biomed Pharmacother. 2019; 109:991-999 [PubMed] Related Publications
BACKGROUND: Aberrant expression of miR-532-3p was involved in progression and development of multiple cancers, whereas miR-532-3p has not been reported in hepatocellular carcinoma (HCC). The aim of this study was to elucidate the functions of miR-532-3p in progression of HCC.
METHODS: Real-time PCR in HCC tissues and cell lines and database analysis were conducted for detection of the expression of miR-532-3p in HCC. Then, the association of miR-532-3p with clinicopathological features and prognosis of HCC patients were statistically measured. Subsequently, we attempted to observe the effects of miR-532-3p on migration, invasion and proliferation of HCC cells by Wound healing assay, Transwell assays, MTT assay and EdU assay. Furthermore, bioinformatics tools, database analysis, luciferase reporter gene assay and rescue experiments were conducted to explore the target of miR-532-3p in HCC, and to explore whether the target mediated the effects of miR-532-3p on HCC cells.
RESULTS: Our findings and data from databases consistently indicated that the miR-532-3p expression level was higher in HCC. In addition, high miR-532-3p expression was found to be closely related to larger tumor size (P =  0.0027), presence of vascular invasion (P =  0.015), and advanced TNM stage (P =  0.015). In addition, experiments in vitro revealed that miR-532-3p promotes migration, invasion and proliferation of HCC cells. Furthermore, receptor protein tyrosine phosphatase T (PTPRT) was identified as the target and mediator of miR-532-3p in HCC cells.
CONCLUSION: Our results demonstrate that miR-532-3p, which is frequently up-regulated in HCC, contributes to HCC cells mobility and proliferation through targeting PTPRT.

Gao Y, Yang F, Su Z, et al.
β1,6 GlcNAc branches-modified protein tyrosine phosphatase Mu attenuates its tyrosine phosphatase activity and promotes glioma cell migration through PLCγ-PKC pathways.
Biochem Biophys Res Commun. 2018; 505(2):569-577 [PubMed] Related Publications
The metastatic potential of malignant tumor has been shown to be correlated with the increased expression of tri- and tetra-antennary β1,6-N-acetylglucosamine (β1,6-GlcNAc) N-glycans. In this study, We found that GnT-V expression was negatively correlated with receptor protein tyrosine phosphatase type μ(RPTPμ) in human glioma tissues. To study whether RPTPμ is a novel substance of GnT-V which further affect RPTPμ's downstream dephosphorylation function, we preform lentiviral infection with GnT-V gene to construct stably transfected GnT-V glial cell lines. We found RPTPμ undergone severer cleavage in GnT-V transfected glioma cells compare to Mock cells. RPTPμ intracellular domain fragments increased while β1,6-GlcNAc-branched N-glycans increased, in consistent with the decrease of RPTPμ's catalytic activity. The results showed that abnormal glycosylation could decrease the phosphorylation activity of PTP μ, and affect PLCγ-PKC pathways. Both protease inhibitor Furin and N-glycan biosynthesis inhibitor swainsonine could decrease cell mobility in GnT-V-U87 transfectants and other glioma cell lines. All results above suggest increased post-translational modification of RPTPμ N-glycans by GnT-V attenuates its tyrosine phosphatase activity and promotes glioma cell migration through PLCγ-PKC pathways, and that the β1,6-GlcNAc-branched N-glycans of RPTPμ play a crucial role in glioma invasivity.

Casar B, Badrock AP, Jiménez I, et al.
RAS at the Golgi antagonizes malignant transformation through PTPRκ-mediated inhibition of ERK activation.
Nat Commun. 2018; 9(1):3595 [PubMed] Free Access to Full Article Related Publications
RAS GTPases are frequently mutated in human cancer. H- and NRAS isoforms are distributed over both plasma-membrane and endomembranes, including the Golgi complex, but how this organizational context contributes to cellular transformation is unknown. Here we show that RAS at the Golgi is selectively activated by apoptogenic stimuli and antagonizes cell survival by suppressing ERK activity through the induction of PTPRκ, which targets CRAF for dephosphorylation. Consistently, in contrast to what occurs at the plasma-membrane, RAS at the Golgi cannot induce melanoma in zebrafish. Inactivation of PTPRκ, which occurs frequently in human melanoma, often coincident with TP53 inactivation, accelerates RAS-ERK pathway-driven melanomagenesis in zebrafish. Likewise, tp53 disruption in zebrafish facilitates oncogenesis driven by RAS from the Golgi complex. Thus, RAS oncogenic potential is strictly dependent on its sublocalization, with Golgi complex-located RAS antagonizing tumor development.

de Mel S, Soon GS, Mok Y, et al.
The Genomics and Molecular Biology of Natural Killer/T-Cell Lymphoma: Opportunities for Translation.
Int J Mol Sci. 2018; 19(7) [PubMed] Free Access to Full Article Related Publications
Extranodal NK/T-cell lymphoma, nasal type (ENKTL), is an aggressive malignancy with a poor prognosis. While the introduction of L-asparaginase in the treatment of this disease has significantly improved the prognosis, the outcome of patients relapsing after asparaginase-based chemotherapy, which occurs in up to 50% of patients with disseminated disease, remains dismal. There is hence an urgent need for effective targeted therapy especially in the relapsed/refractory setting. Gene expression profiling studies have provided new perspectives on the molecular biology, ontogeny and classification of ENKTL and further identified dysregulated signaling pathways such as Janus associated kinase (/Signal Transducer and activation of transcription (JAK/STAT), Platelet derived growth factor (PDGF), Aurora Kinase and NF-κB, which are under evaluation as therapeutic targets. Copy number analyses have highlighted potential tumor suppressor genes such as PR Domain Zinc Finger Protein 1 (PRDM1) and protein tyrosine phosphatase kappa (PTPRK) while next generation sequencing studies have identified recurrently mutated genes in pro-survival and anti-apoptotic pathways. The discovery of epigenetic dysregulation and aberrant microRNA activity has broadened our understanding of the biology of ENKTL. Importantly, immunotherapy via Programmed Cell Death -1 (PD-1) and Programmed Cell Death Ligand1 (PD-L1) checkpoint signaling inhibition is emerging as an attractive therapeutic strategy in ENKTL. Herein, we present an overview of the molecular biology and genomic landscape of ENKTL with a focus on the most promising translational opportunities.

Zhang G, Liu X, Wu J, et al.
Expression and clinical relations of protein tyrosine phosphatase receptor type S in esophageal squamous cell carcinoma.
Histol Histopathol. 2018; 33(11):1181-1188 [PubMed] Related Publications
Protein tyrosine phosphatase receptor type S is a tumor suppressor gene, located at chromosome 19p13.3, frequently inactivated through deletions or epigenetic mechanisms in many types of cancers. In this study, we investigate protein tyrosine phosphatase receptor S (PTPRS) expression level, clinicopathological and prognostic significance in 205 cases of esophageal squamous cell carcinoma (ESCC). Paraffin embedded tissue with immunohistochemistry methods was adopted to exam PTPRS expression in ESCC and paired normal esophageal mucosa tissues on Tissue Microarrays (TMAs). The protein tyrosine phosphatase receptor S was significantly down-regulated in ESCC (58.0%) relative to normal tissues (43.9%) (P=0.006). Statistical analysis revealed that reduced PTPRS expression was significantly associated with TNM stage (P=0.013), invasion depth (P<0.001), local lymph node metastasis (P=0.042) and tumor differentiation (P=0.001). Furthermore, Kaplan-Meier survival analysis revealed that low expression of PTPRS significantly correlated with poor survival of ESCC patients (P=0.002). Cox regression analysis confirmed PTPRS expression as an independent predictor of the overall survival of ESCC patients (HR=1.573, P=0.049). The 5-year overall survival rates in patients with high and low PTPRS expression were 50.6% and 37.2%, respectively. PTPRS deficiency is independently associated with shorter survival and increased recurrence in patients. Our data offer convincing evidence that loss of PTPRS expression may predict an aggressive clinical course in ESCC patients. PTPRS may function as a tumor suppressor and play an important role in ESCC growth and metastasis.

Xu L, Xu X, Huang H, et al.
MiR-1260b promotes the migration and invasion in non-small cell lung cancer via targeting PTPRK.
Pathol Res Pract. 2018; 214(5):776-783 [PubMed] Related Publications
OBJECTIVE: Non-small cell lung cancer (NSCLC) accounts for 80-85% of lung cancer cases which cause most of cancer-related deaths globally. As our previous study discovered miR-1260b can be regarded as a specific signature for metastasis in NSCLC patients. However, the molecular mechanisms of miR-1260b underlying NSCLC progression and metastasis remain dismal.
METHODS: The expression of miR-1260b in NSCLC tissues and cell lines were examined by real-time PCR, the effects of miR-1260b on cell migration, invasion and proliferation were evaluated in vitro. Furthermore, luciferase reporter assay was performed to identify the targets of miR-1260b, and the association between miR-1260b and its target gene was determined by real-time PCR and western blot assay.
RESULTS: The results showed that miR-1260b was significantly upregulated in NSCLC cell lines. The inhibition of miR-1260b expression decreased the migratory and invasive rates in A549 cells while miR-1260b overexpression had the opposite effect. Furthermore, PTPRK was identified as a direct target of miR-1260b, and PTPRK expression was inversely correlated with miR-1260b in NSCLC cell lines and clinical tissues.
CONCLUSIONS: These results suggested that miR-1260b may play an important role in NSCLC metastasis progression and could serve as a putative target for diagnosis and treatment of NSCLC.

Chen Y, Xu C, Harirforoosh S, et al.
Analysis of PTPRK polymorphisms in association with risk and age at onset of Alzheimer's disease, cancer risk, and cholesterol.
J Psychiatr Res. 2018; 96:65-72 [PubMed] Free Access to Full Article Related Publications
The human receptor-type protein-tyrosine phosphatase kappa (PTPRK) gene is highly expressed in human brain and was previously associated with an increased risk of neuropsychiatric disorders and cancer. This study investigated the association of 52 single nucleotide polymorphisms (SNPs) in PTPRK with the risk and age at onset (AAO) of Alzheimer's disease (AD) in 791 AD patients and 782 controls. Our data analysis showed that five SNPs (top SNP rs4895829 with p = 0.0125) were associated with the risk of AD based on a multiple logistic regression (p < 0.05); while six SNPs (top SNP rs1891150 with p = 8.02 × 10

Visser E, Franken IA, Brosens LAA, et al.
Targeted next-generation sequencing of commonly mutated genes in esophageal adenocarcinoma patients with long-term survival.
Dis Esophagus. 2017; 30(9):1-8 [PubMed] Related Publications
Survival of patients with esophageal adenocarcinoma remains poor and individual differences in prognosis remain unexplained. This study investigated whether gene mutations can explain why patients with high-risk (pT3-4, pN+) esophageal adenocarcinoma survive past 5 years after esophagectomy. Six long-term survivors (LTS) (≥5 years survival without recurrence) and six short-term survivors (STS) (<2 years survival due to recurrence) who underwent resection without neoadjuvant therapy for high-risk esophageal adenocarcinoma were included. Targeted next-generation sequencing of 16 genes related to esophageal adenocarcinoma was performed. Mutations were compared between the LTS and STS and described in comparison with literature. A total of 48 mutations in 10 genes were identified. In the LTS, the median number of mutated genes per sample was 5 (range: 0-5) and the samples together harbored 22 mutations in 8 genes: APC (n = 1), CDH11 (n = 2), CDKN2A (n = 2), FAT4 (n = 5), KRAS (n = 1), PTPRD (n = 1), TLR4 (n = 8), and TP53 (n = 2). The median number of mutated genes per sample in the STS was 4 (range: 1-8) and in total 26 mutations were found in six genes: CDH11 (n = 5), FAT4 (n = 7), SMAD4 (n = 1), SMARCA4 (n = 1), TLR4 (n = 7), and TP53 (n = 5). CDH11, CDKN2A, FAT4, TLR4, and TP53 were mutated in at least 2 LTS or STS, exceeding mutation rates in literature. Mutations across the LTS and STS were found in 10 of the 16 genes. The results warrant future studies to investigate a larger range of genes in a larger sample size. This may result in a panel with prognostic genes, to predict individual prognosis and to select effective individualized therapy for patients with esophageal adenocarcinoma.

Han T, Schatoff EM, Murphy C, et al.
R-Spondin chromosome rearrangements drive Wnt-dependent tumour initiation and maintenance in the intestine.
Nat Commun. 2017; 8:15945 [PubMed] Free Access to Full Article Related Publications
Defining the genetic drivers of cancer progression is a key in understanding disease biology and developing effective targeted therapies. Chromosome rearrangements are a common feature of human malignancies, but whether they represent bona fide cancer drivers and therapeutically actionable targets, requires functional testing. Here, we describe the generation of transgenic, inducible CRISPR-based mouse systems to engineer and study recurrent colon cancer-associated EIF3E-RSPO2 and PTPRK-RSPO3 chromosome rearrangements in vivo. We show that both Rspo2 and Rspo3 fusion events are sufficient to initiate hyperplasia and tumour development in vivo, without additional cooperating genetic events. Rspo-fusion tumours are entirely Wnt-dependent, as treatment with an inhibitor of Wnt secretion, LGK974, drives rapid tumour clearance from the intestinal mucosa without effects on normal intestinal crypts. Altogether, our study provides direct evidence that endogenous Rspo2 and Rspo3 chromosome rearrangements can initiate and maintain tumour development, and indicate a viable therapeutic window for LGK974 treatment of RSPO-fusion cancers.

Januchowski R, Sterzyńska K, Zawierucha P, et al.
Microarray-based detection and expression analysis of new genes associated with drug resistance in ovarian cancer cell lines.
Oncotarget. 2017; 8(30):49944-49958 [PubMed] Free Access to Full Article Related Publications
PURPOSE: The present study is to discover a new genes associated with drug resistance development in ovarian cancer.
METHODS: We used microarray analysis to determine alterations in the level of expression of genes in cisplatin- (CisPt), doxorubicin- (Dox), topotecan- (Top), and paclitaxel- (Pac) resistant variants of W1 and A2780 ovarian cancer cell lines. Immunohistochemistry assay was used to determine protein expression in ovarian cancer patients.
RESULTS: We observed alterations in the expression of 22 genes that were common to all three cell lines that were resistant to the same cytostatic drug. The level of expression of 13 genes was upregulated and that of nine genes was downregulated. In the CisPt-resistant cell line, we observed downregulated expression of ABCC6, BST2, ERAP2 and MCTP1; in the Pac-resistant cell line, we observe upregulated expression of ABCB1, EPHA7 and RUNDC3B and downregulated expression of LIPG, MCTP1, NSBP1, PCDH9, PTPRK and SEMA3A. The expression levels of three genes, ABCB1, ABCB4 and IFI16, were upregulated in the Dox-resistant cell lines. In the Top-resistant cell lines, we observed increased expression levels of ABCG2, HERC5, IFIH1, MYOT, S100A3, SAMD4A, SPP1 and TGFBI and decreased expression levels of MCTP1 and PTPRK. The expression of EPHA7, IFI16, SPP1 and TGFBI was confirmed at protein level in analyzed ovarian cancer patients..
CONCLUSIONS: The expression profiles of the investigated cell lines indicated that new candidate genes are related to the development of resistance to the cytostatic drugs that are used in first- and second-line chemotherapy of ovarian cancer.

Sekine S, Ogawa R, Hashimoto T, et al.
Comprehensive characterization of RSPO fusions in colorectal traditional serrated adenomas.
Histopathology. 2017; 71(4):601-609 [PubMed] Related Publications
AIMS: Traditional serrated adenoma (TSA) is a rare but distinct type of colorectal polyp. Our previous study showed that PTPRK-RSPO3 fusions are frequent and characteristic genetic alterations in TSAs. This study aimed to characterize comprehensively the prevalence and variability of RSPO fusions in colorectal TSAs.
METHODS AND RESULTS: We examined RSPO expression and explored novel RSPO fusions in 129 TSAs, including 66 lesions analysed previously for WNT pathway gene mutations. Quantitative polymerase chain reaction (qPCR) analyses identified three and 43 TSAs overexpressing RSPO2 and RSPO3, respectively, whereas the expression of RSPO1 and RSPO4 was marginal or undetectable in all cases. RSPO overexpression was always mutually exclusive with other WNT pathway gene mutations. Known PTPRK-RSPO3 fusions were detected in 37 TSAs, all but one of which overexpressed RSPO3. In addition, rapid amplification of cDNA ends revealed three novel RSPO fusion transcripts, an NRIP1-RSPO2 fusion and two PTPRK-RSPO3 fusion isoforms, in six TSAs. Overall, 43 TSAs had RSPO fusions (33%), whereas four TSAs (3%) overexpressed RSPO in the absence of RSPO fusions. TSAs with RSPO fusions showed several clinicopathological features, including distal localization (P = 0.0063), larger size (P = 0.0055), prominent ectopic crypt foci (P = 8.4 × 10
CONCLUSIONS: The present study identified RSPO fusion transcripts, including three novel transcripts, in one-third of colorectal TSAs and showed that PTPRK-RSPO3 fusions were the predominant cause of RSPO overexpression in colorectal TSA.

Szaumkessel M, Wojciechowska S, Janiszewska J, et al.
Recurrent epigenetic silencing of the PTPRD tumor suppressor in laryngeal squamous cell carcinoma.
Tumour Biol. 2017; 39(3):1010428317691427 [PubMed] Related Publications
Cellular processes like differentiation, mitotic cycle, and cell growth are regulated by tyrosine kinases with known oncogenic potential and tyrosine phosphatases that downmodulate the first. Therefore, tyrosine phosphatases are recurrent targets of gene alterations in human carcinomas. We and others suggested recently a tumor suppressor function of the PTPRD tyrosine phosphatase and reported homozygous deletions of the PTPRD locus in laryngeal squamous cell carcinoma. In this study, we investigated other gene-inactivating mechanisms potentially targeting PTPRD, including loss-of-function mutations and also epigenetic alterations like promoter DNA hypermethylation. We sequenced the PTPRD gene in eight laryngeal squamous cell carcinoma cell lines but did not identify any inactivating mutations. In contrast, by bisulfite pyrosequencing of the gene promoter region, we identified significantly higher levels of methylation (p = 0.001 and p = 0.0002, respectively) in 9/14 (64%) laryngeal squamous cell carcinoma cell lines and 37/79 (47%) of primary laryngeal squamous cell carcinoma tumors as compared to normal epithelium of the upper aerodigestive tract. There was also a strong correlation (p = 0.0001) between methylation and transcriptional silencing for the PTPRD gene observed in a cohort of 497 head and neck tumors from The Cancer Genome Atlas dataset suggesting that DNA methylation is the main mechanism of PTPRD silencing in these tumors. In summary, our data provide further evidence of the high incidence of PTPRD inactivation in laryngeal squamous cell carcinoma. We suggest that deletions and loss-of-function mutations are responsible for PTPRD loss only in a fraction of cases, whereas DNA methylation is the dominating mechanism of PTPRD inactivation.

Van Renne N, Roca Suarez AA, Duong FHT, et al.
miR-135a-5p-mediated downregulation of protein tyrosine phosphatase receptor delta is a candidate driver of HCV-associated hepatocarcinogenesis.
Gut. 2018; 67(5):953-962 [PubMed] Free Access to Full Article Related Publications
BACKGROUND AND AIMS: HCV infection is a leading risk factor of hepatocellular carcinoma (HCC). However, even after viral clearance, HCC risk remains elevated. HCV perturbs host cell signalling to maintain infection, and derailed signalling circuitry is a key driver of carcinogenesis. Since protein phosphatases are regulators of signalling events, we aimed to identify phosphatases that respond to HCV infection with relevance for hepatocarcinogenesis.
METHODS: We assessed mRNA and microRNA (miRNA) expression profiles in primary human hepatocytes, liver biopsies and resections of patients with HCC, and analysed microarray and RNA-seq data from paired liver biopsies of patients with HCC. We revealed changes in transcriptional networks through gene set enrichment analysis and correlated phosphatase expression levels to patient survival and tumour recurrence.
RESULTS: We demonstrate that tumour suppressor protein tyrosine phosphatase receptor delta (PTPRD) is impaired by HCV infection in vivo and in HCC lesions of paired liver biopsies independent from tissue inflammation or fibrosis. In liver tissue adjacent to tumour, high PTPRD levels are associated with a dampened transcriptional activity of STAT3, an increase of patient survival from HCC and reduced tumour recurrence after surgical resection. We identified miR-135a-5p as a mechanistic regulator of hepatic PTPRD expression in patients with HCV.
CONCLUSIONS: We previously demonstrated that STAT3 is required for HCV infection. We conclude that HCV promotes a STAT3 transcriptional programme in the liver of patients by suppressing its regulator PTPRD via upregulation of miR-135a-5p. Our results show the existence of a perturbed PTPRD-STAT3 axis potentially driving malignant progression of HCV-associated liver disease.

Picco G, Petti C, Centonze A, et al.
Loss of AXIN1 drives acquired resistance to WNT pathway blockade in colorectal cancer cells carrying RSPO3 fusions.
EMBO Mol Med. 2017; 9(3):293-303 [PubMed] Free Access to Full Article Related Publications
In colorectal cancer (CRC), WNT pathway activation by genetic rearrangements of RSPO3 is emerging as a promising target. However, its low prevalence severely limits availability of preclinical models for in-depth characterization. Using a pipeline designed to suppress stroma-derived signal, we find that RSPO3 "outlier" expression in CRC samples highlights translocation and fusion transcript expression. Outlier search in 151 CRC cell lines identified VACO6 and SNU1411 cells as carriers of, respectively, a canonical PTPRK(e1)-RSPO3(e2) fusion and a novel PTPRK(e13)-RSPO3(e2) fusion. Both lines displayed marked

Zhao Y, Scott A, Zhang P, et al.
Regulation of paxillin-p130-PI3K-AKT signaling axis by Src and PTPRT impacts colon tumorigenesis.
Oncotarget. 2017; 8(30):48782-48793 [PubMed] Free Access to Full Article Related Publications
Protein tyrosine phosphatase receptor T (PTPRT) is frequently mutated in a variety of human cancers including colorectal cancer. Here we report that PTPRT knockout increases the size of mouse colon tumors in the Apcmin+/- genetic background, suggesting that inactivation of PTPRT promotes tumor progression. We previously demonstrated that PTPRT dephosphorylates paxillin at tyrosine-Y88 residue. Consistently, phosphorylation of Y88 paxillin (pY88) is up-regulated in colon tumors derived from Apcmin+/- Ptprt-/- mice. An important downstream effector of pY88 paxillin is the oncogene Akt. Here, we show that pY88 paxillin impacts the Akt pathway by regulating the interaction between p130cas and the p85 regulatory subunit of PI3-Kinase. Additionally, while pY88 paxillin is a substrate of the tumor suppressor phosphatase PTPRT, the corresponding kinase has not been previously identified. In this study, we demonstrate that the oncogenic kinase Src directly phosphorylates paxillin at Y88. Moreover, colorectal cancer cells that express high levels of pY88 paxillin are sensitive to dasatinib treatment, suggesting that pY88 paxillin may serve as a predictive biomarker for Src family kinase inhibitors.

Spina V, Khiabanian H, Messina M, et al.
The genetics of nodal marginal zone lymphoma.
Blood. 2016; 128(10):1362-73 [PubMed] Free Access to Full Article Related Publications
Nodal marginal zone lymphoma (NMZL) is a rare, indolent B-cell tumor that is distinguished from splenic marginal zone lymphoma (SMZL) by the different pattern of dissemination. NMZL still lacks distinct markers and remains orphan of specific cancer gene lesions. By combining whole-exome sequencing, targeted sequencing of tumor-related genes, whole-transcriptome sequencing, and high-resolution single nucleotide polymorphism array analysis, we aimed at disclosing the pathways that are molecularly deregulated in NMZL and we compare the molecular profile of NMZL with that of SMZL. These analyses identified a distinctive pattern of nonsilent somatic lesions in NMZL. In 35 NMZL patients, 41 genes were found recurrently affected in ≥3 (9%) cases, including highly prevalent molecular lesions of MLL2 (also known as KMT2D; 34%), PTPRD (20%), NOTCH2 (20%), and KLF2 (17%). Mutations of PTPRD, a receptor-type protein tyrosine phosphatase regulating cell growth, were enriched in NMZL across mature B-cell tumors, functionally caused the loss of the phosphatase activity of PTPRD, and were associated with cell-cycle transcriptional program deregulation and increased proliferation index in NMZL. Although NMZL shared with SMZL a common mutation profile, NMZL harbored PTPRD lesions that were otherwise absent in SMZL. Collectively, these findings provide new insights into the genetics of NMZL, identify PTPRD lesions as a novel marker for this lymphoma across mature B-cell tumors, and support the distinction of NMZL as an independent clinicopathologic entity within the current lymphoma classification.

Li J, Sordella R, Powers S
Effectors and potential targets selectively upregulated in human KRAS-mutant lung adenocarcinomas.
Sci Rep. 2016; 6:27891 [PubMed] Free Access to Full Article Related Publications
Genetic and proteomic analysis of human tumor samples can provide an important compliment to information obtained from model systems. Here we examined protein and gene expression from the Cancer Genome and Proteome Atlases (TCGA and TCPA) to characterize proteins and protein-coding genes that are selectively upregulated in KRAS-mutant lung adenocarcinomas. Phosphoprotein activation of several MAPK signaling components was considerably stronger in KRAS-mutants than any other group of tumors, even those with activating mutations in receptor tyrosine kinases (RTKs) and BRAF. Co-occurring mutations in KRAS-mutants were associated with differential activation of PDK1 and PKC-alpha. Genes showing strong activation in RNA-seq data included negative regulators of RTK/RAF/MAPK signaling along with potential oncogenic effectors including activators of Rac and Rho proteins and the receptor protein-tyrosine phosphatase genes PTPRM and PTPRE. These results corroborate RAF/MAPK signaling as an important therapeutic target in KRAS-mutant lung adenocarcinomas and pinpoint new potential targets.

Storm EE, Durinck S, de Sousa e Melo F, et al.
Targeting PTPRK-RSPO3 colon tumours promotes differentiation and loss of stem-cell function.
Nature. 2016; 529(7584):97-100 [PubMed] Related Publications
Colorectal cancer remains a major unmet medical need, prompting large-scale genomics efforts in the field to identify molecular drivers for which targeted therapies might be developed. We previously reported the identification of recurrent translocations in R-spondin genes present in a subset of colorectal tumours. Here we show that targeting RSPO3 in PTPRK-RSPO3-fusion-positive human tumour xenografts inhibits tumour growth and promotes differentiation. Notably, genes expressed in the stem-cell compartment of the intestine were among those most sensitive to anti-RSPO3 treatment. This observation, combined with functional assays, suggests that a stem-cell compartment drives PTPRK-RSPO3 colorectal tumour growth and indicates that the therapeutic targeting of stem-cell properties within tumours may be a clinically relevant approach for the treatment of colorectal tumours.

Song L, Jiang W, Liu W, et al.
Protein tyrosine phosphatases receptor type D is a potential tumour suppressor gene inactivated by deoxyribonucleic acid methylation in paediatric acute myeloid leukaemia.
Acta Paediatr. 2016; 105(3):e132-41 [PubMed] Related Publications
AIM: Protein tyrosine phosphatases receptor type D (PTPRD) is a tumour suppressor gene, and its epigenetic silencing is frequently found in glioblastoma. As aberrant deoxyribonucleic acid (DNA) methylation patterning has been shown to play a role in leukaemogenesis, we studied the promoter methylation, expression profiles and molecular functions of PTPRD in paediatric patients with acute myeloid leukaemia (AML).
METHODS: Bone marrow specimens were obtained from 32 Chinese patients with a mean age of 7.2 years (range 1.1-16.5). PTPRD and methylation status were evaluated by real-time polymerase chain reaction (PCR) and methylation-specific PCR. Western blot and flow cytometry techniques were also used.
RESULTS: PTPRD expression was decreased by promoter region methylation in six AML cells and methylated in 21 (65.6%) of the 32 samples. In addition, PTPRD expression could be induced by the DNA demethylating agent 5-aza-2'-deoxycytidine. Furthermore, functional studies showed that overexpression of PTPRD in AML cells inhibited cell proliferation and clonogenicity as well as inducing apoptosis. However, PTPRD knockdown increased cell proliferation. These effects were associated with downregulation of cyclin D1, c-myc and upregulation of Bax.
CONCLUSION: The results of this study demonstrated that PTPRD was a potential tumour suppressor gene inactivated by DNA methylation in paediatric AML.

Zhou R, Zhou X, Yin Z, et al.
Tumor invasion and metastasis regulated by microRNA-184 and microRNA-574-5p in small-cell lung cancer.
Oncotarget. 2015; 6(42):44609-22 [PubMed] Free Access to Full Article Related Publications
Small-cell lung cancer (SCLC) is a highly aggressive neuroendocrine tumor that has an extremely poor clinical prognosis. Metastasis is the key event in SCLC progression, but its mechanism has not been fully elucidated. MicroRNAs (miRNAs) have been proven to participate in cancer processes, but their function in SCLC has not been thoroughly studied either. Here, we performed microarray and quantitative real-time PCR (qRT-PCR) analyses to identify the miRNAs associated with metastasis and prognosis in SCLC as well as the correlation between serum and tissue. We also explored these miRNAs' promising molecular mechanisms by 3'UTR reporter assay and immunoblotting. We showed that miR-184 significantly attenuated the metastasis of SCLC, whereas miR-574-5p enhanced it. Both miRNAs were found to participate in β-catenin signaling by suppressing protein tyrosine phosphatase receptor type U (PTPRU) or endothelial PAS domain protein 1 (EPAS1). Furthermore, miR-574-5p was verified as an independent prognostic risk factor for SCLC. Taken together, our findings provide a comprehensive analysis of the miRNA expression pattern in SCLC and indicate that miRNAs may serve as potential therapeutic and prognostic predictors in SCLC.

Yuwanita I, Barnes D, Monterey MD, et al.
Increased metastasis with loss of E2F2 in Myc-driven tumors.
Oncotarget. 2015; 6(35):38210-24 [PubMed] Free Access to Full Article Related Publications
In human breast cancer, mortality is associated with metastasis to distant sites. Therefore, it is critical to elucidate the biological mechanisms that underlie tumor progression and metastasis. Using signaling pathway signatures we previously predicted a role for E2F transcription factors in Myc induced tumors. To test this role we interbred MMTV-Myc transgenic mice with E2F knockouts. Surprisingly, we observed that the loss of E2F2 sharply increased the percentage of lung metastasis in MMTV-Myc transgenic mice. Examining the gene expression profile from these tumors, we identified genetic components that were potentially involved in mediating metastasis. These genes were filtered to uncover the genes involved in metastasis that also impacted distant metastasis free survival in human breast cancer. In order to elucidate the mechanism by which E2F2 loss enhanced metastasis we generated knockdowns of E2F2 in MDA-MB-231 cells and observed increased migration in vitro and increased lung colonization in vivo. We then examined genes that were differentially regulated between tumors from MMTV-Myc, MMTV-Myc E2F2-/-, and lung metastases samples and identified PTPRD. To test the role of PTPRD in E2F2-mediated breast cancer metastasis, we generated a knockdown of PTPRD in MDA-MB-231 cells. We noted that decreased levels of PTPRD resulted in decreased migration in vitro and decreased lung colonization in vivo. Taken together, these data indicate that E2F2 loss results in increased metastasis in breast cancer, potentially functioning through a PTPRD dependent mechanism.

McPherson JR, Ong CK, Ng CC, et al.
Whole-exome sequencing of breast cancer, malignant peripheral nerve sheath tumor and neurofibroma from a patient with neurofibromatosis type 1.
Cancer Med. 2015; 4(12):1871-8 [PubMed] Free Access to Full Article Related Publications
Neurofibromatosis type 1 (NF1) is a genetic disorder characterized by the development of multiple neurofibromas, cafe-au-lait spots, and Lisch nodules. Individuals with NF1 are at increased risk of developing various tumors, such as malignant peripheral nerve sheath tumor (MPNST), pheochromocytoma, leukemia, glioma, rhabdomyosarcoma, and breast cancer. Here, we describe the exome sequencing of breast cancer, MPNST, and neurofibroma from a patient with NF1. We identified a germline mutation in the NF1 gene which resulted in conversion of leucine to proline at amino acid position 847. In addition, we showed independent somatic NF1 mutations in all the three tumors (frameshift insertion in breast cancer (p.A985fs), missense mutation in MPNST (p.G23R), and inframe deletion in dermal neurofibroma (p.L1876del-Inf)), indicating that a second hit in NF1 resulting in the loss of function could be important for tumor formation. Each tumor had a distinct genomic profile with mutually exclusive mutations in different genes. Copy number analysis revealed multiple copy number alterations in the breast cancer and the MPNST, but not the benign neurofibroma. Germline loss of chromosome 6q22.33, which harbors two potential tumor suppressor genes, PTPRK and LAMA2, was also identified; this may increase tumor predisposition further. In the background of NF1 syndrome, although second-hit NF1 mutation is critical in tumorigenesis, different additional mutations are required to drive the formation of different tumors.

Soulières D, Hirsch FR, Shepherd FA, et al.
PTPRF Expression as a Potential Prognostic/Predictive Marker for Treatment with Erlotinib in Non-Small-Cell Lung Cancer.
J Thorac Oncol. 2015; 10(9):1364-1369 [PubMed] Related Publications
INTRODUCTION: EGFR mutations and anaplastic lymphoma kinase rearrangements are, to date, the only approved biomarkers to select treatment for non-small-cell lung cancer (NSCLC). However, there is considerable interest in identifying other predictive markers. The PTPRF gene has been suggested as a marker of interest in NSCLC and other tumor types.
METHODS: This hypothesis-generating retrospective analysis examined data from two studies of erlotinib in NSCLC, Marker Identification Trial (MERIT; n = 102) and Sequential Tarceva in Unresectable NSCLC (SATURN; n = 262), to determine whether PTPRF expression was prognostic and/or predictive of patient outcomes. Exploratory analyses were conducted using quantitative reverse transcription polymerase chain reaction on existing formalin-fixed paraffin-embedded samples, to assess gene expression levels, including PTPRF. High versus low levels of expression were dichotomized using the median with B2M as a control comparator. Progression-free survival and overall survival were then compared for patients with high versus low levels of PTPRF in the two studies.
RESULTS: PTPRF expression was found to be prognostic for shorter overall survival but was also significantly predictive of improved survival with erlotinib versus placebo in SATURN (hazard ratio, 0.45 [95% confidence interval, CI, 0.30-0.69] in PTPRF high versus 0.96 [95% CI, 0.62-1.48] in PTPRF low; interaction p = 0.02), even in the EGFR wild-type subpopulation (adjusted hazard ratio, 0.44 [95% CI, 0.29-0.68] versus 0.96 [95% CI, 0.62-1.48]; interaction p = 0.01).
CONCLUSIONS: PTPRF may have value as a predictive marker to identify which patients can obtain the greatest benefit from erlotinib in the post-first-line setting. Further research is warranted to determine the potential value of this marker in clinical decision-making.

Peyser ND, Du Y, Li H, et al.
Loss-of-Function PTPRD Mutations Lead to Increased STAT3 Activation and Sensitivity to STAT3 Inhibition in Head and Neck Cancer.
PLoS One. 2015; 10(8):e0135750 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Protein tyrosine phosphatase receptor type D (PTPRD) is a putative tumor suppressor in several cancers including head and neck squamous cell carcinoma (HNSCC). STAT3 is a frequently hyperactivated oncogene in HNSCC. As STAT3 is a direct substrate of PTPRD, we sought to determine the genetic or epigenetic alterations of PTPRD that contribute to overactive STAT3 in HNSCC.
METHODS: We analyzed data from The Cancer Genome Atlas (TCGA) and our previous whole-exome sequencing study and summarized the mutation, methylation, and copy number status of PTPRD in HNSCC and other cancers. In vitro studies involved standard transfection and MTT protocols, as well as methylation-specific PCR.
RESULTS: Our findings indicate that PTPRD mutation, rather than methylation or copy number alteration, is the primary mechanism by which PTPRD function is lost in HNSCC. We demonstrate that overexpression of wild-type PTPRD in HNSCC cells significantly inhibits growth and STAT3 activation while PTPRD mutants do not, suggesting that mutation may lead to loss of function and subsequent hyper-phosphorylation of PTPRD substrates, especially STAT3. Importantly, we determined that HNSCC cells harboring an endogenous PTPRD mutation are more sensitive to STAT3 blockade than PTPRD wild-type cells. We additionally found that PTPRD mRNA expression does not correlate with pSTAT3 expression, suggesting that alterations that manifest through altered mRNA expression, including hypermethylation and gene copy number alterations, do not significantly contribute to STAT3 overactivation in HNSCC.
CONCLUSION: PTPRD mutation, but not methylation or copy number loss, may serve as a predictive biomarker of sensitivity to STAT3 inhibitors in HNSCC.

Beothe T, Zubakov D, Kovacs G
Homozygous losses detected by array comparative genomic hybridization in multiplex urothelial carcinomas of the bladder.
Cancer Genet. 2015; 208(9):434-40 [PubMed] Related Publications
Urothelial carcinomas (UCs) may present at first as a solitary or multifocal neoplasm. We applied high resolution array comparative genomic hybridization to 24 solitary and 32 multiplex UCs and used the hidden Markov model algorithm to identify the copy number changes at the probe level. Copy number losses and homozygous deletions at the chromosome 9p region affecting the CDKN2A and MTAP genes were the most frequent alterations in both groups of tumors. We have delineated two new tumor suppressor gene regions at chromosome 9p that harbor the PTPRD and BNC2 genes. Copy number losses at chromosomal regions 2q, 8p, and 18p occurred preferentially in solitary UCs, whereas multiplex UCs displayed loss of large chromosomal regions at 9q, 10q, 11q, 18q, and 21q. Homozygous deletions harboring loci of cell adhesion genes such as claudins, desmocollins, and desmogleins were seen exclusively in multiplex UCs. Amplifications occurred only in invasive G3 UCs irrespective of staging. Our study suggests that solitary and multiplex UCs may have divergent genetic pathways. The biallelic inactivation of cellular adhesion genes by homozygous deletions in multiplex UCs may explain the frequent intravesical spreading of tumor cells. .

Peyser ND, Freilino M, Wang L, et al.
Frequent promoter hypermethylation of PTPRT increases STAT3 activation and sensitivity to STAT3 inhibition in head and neck cancer.
Oncogene. 2016; 35(9):1163-9 [PubMed] Free Access to Full Article Related Publications
Signal transducer and activator of transcription 3 (STAT3) overactivation is a common event in many cancers, including head and neck squamous cell carcinoma (HNSCC), where STAT3 represents a promising therapeutic target. HNSCC is not characterized by frequent kinase mutations, in contrast to some malignancies where mutational activation of kinases upstream of STAT3 is common. Instead, STAT3 may be activated by loss-of-function of negative regulators of STAT3, including by promoter hypermethylation of PTPRT. Here we first analyzed The Cancer Genome Atlas data and determined that the PTPRT promoter is frequently hypermethylated in several cancers, including HNSCC (60.1% of tumors analyzed) in association with downregulation of PTPRT mRNA expression and upregulation of pSTAT3 expression. These findings were confirmed in an independent cohort of HNSCC tumors by methylation-specific PCR and immunohistochemistry. We demonstrate that PTPRT promoter methylation and gene silencing is reversible in HNSCC cells, leading to PTPRT-specific downregulation of pSTAT3 expression. We further show that PTPRT promoter methylation is significantly associated with sensitivity to STAT3 inhibition in HNSCC cells, suggesting that PTPRT promoter methylation may serve as a predictive biomarker for responsiveness to STAT3 inhibitors in clinical development.

Yao Y, Shao J, Wu J, et al.
The Functional Variant in the 3'UTR of PTPRT with the Risk of Esophageal Squamous Cell Carcinoma in a Chinese Population.
Cell Physiol Biochem. 2015; 36(1):306-14 [PubMed] Related Publications
BACKGROUND/AIMS: PTPRT is an essential tumor suppressor that plays crucial roles in regulating the mechanisms of tumorigenesis. Polymorphisms in PTPRT have been reported associated with human longevity, but their association with the risk of esophageal squamous cell carcinoma (ESCC) has not been found so far. In this study, we focused on the miRNAs associated SNPs in the 3'-UTR of PTPRT to investigate the further relationship of the SNPs with miRNAs among Chinese ESCC patients.
METHODS: We performed case-control study including 790 ESCC patients and 749 cancer-free controls. Genotyping, real time PCR assay, cell transfection and the dual luciferase reporter assay were used in our study.
RESULTS: We found that patients suffering from smoking exposure, drinking exposure and the history of cancer indicated to be the susceptible population by comparing with controls. Besides, SNP rs2866943 in PTPRT 3'-UTR was involved in the occurrence of ESCC by acting as a protective factor while rs6029959 acting a risk factor. SNP rs2866943 was also could be regulated by miR-218 which caused a down-regulation of PTPRT in patients with CT and TT genotype. Furthermore, the carriers of CT and TT genotype presented a small tumor size as well as the low probability of metastasis.
CONCLUSION: Our findings have shown that the SNP rs2866943 in PTPRT 3'-UTR, through disrupting the regulatory role of miR-218 in PTPRT expression, rs2866943 in PTPRT might act as a protective factor in the pathogenesis of ESCC.

Wang D, Tan J, Xu Y, et al.
Identification of MicroRNAs and target genes involvement in hepatocellular carcinoma with microarray data.
Hepatogastroenterology. 2015 Mar-Apr; 62(138):378-82 [PubMed] Related Publications
The aim of the study is to identify the differentially expressed microRNAs (miRNAs) between hepatocellular carcinoma (HCC) samples and controls and provide new diagnostic potential miRNAs for HCC. The miRNAs expression profile data GSE20077 included 7 HCC samples, 1 HeLa sample and 3 controls. Differentially expressed miRNAs (DE-miRNAs) were identified by t-test and wilcox test. The miRNA with significantly differential expression was chosen for further analysis. Target genes for this miRNA were selected using TargetScan and miRbase database. STRING software was applied to construct the target genes interaction network and topology analysis was carried out to identify the hub gene in the network. And we identified the mechanism for affecting miRNA function. A total of 54 differentially expressed miRNAs were identified, in which there were 13 miRNAs published to be related to HCC. The differentially expressed hsa-miR-106b was chosen for further analysis and PTPRT (Receptor-type tyrosine-protein phosphatase T) was its potential target gene. The target genes interaction network was constructed among 33 genes, in which PTPRT was the hub gene. We got the conclusion that the differentially expressed hsa-miR-106b may play an important role in the development of HCC by regulating the expression of its potential target gene PT-PRT.

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