Protein Tyrosine Phosphatase Receptor Delta Research Articles

Loss of protein tyrosine phosphatase receptor delta PTPRD increases the number of cortical neurons, impairs synaptic function and induces autistic-like behaviors in adult mice

BackgroundThe brain cortex is responsible for many higher-level cognitive functions. Disruptions during cortical development have long-lasting consequences on brain function and are associated with the etiology of brain disorders. We previously found that the protein tyrosine phosphatase receptor delta Ptprd, which is genetically associated with several human neurodevelopmental disorders, is essential to cortical brain development. Loss of Ptprd expression induced an aberrant increase of excitatory neurons in embryonic and neonatal mice by hyper-activating the pro-neurogenic receptors TrkB and PDGFRβ in neural precursor cells. However, whether these alterations have long-lasting consequences in adulthood remains unknown.ResultsHere, we found that in Ptprd+/- or Ptprd-/- mice, the developmental increase of excitatory neurons persists through adulthood, affecting excitatory synaptic function in the medial prefrontal cortex. Likewise, heterozygosity or homozygosity for Ptprd also induced an increase of inhibitory cortical GABAergic neurons and impaired inhibitory synaptic transmission. Lastly, Ptprd+/- or Ptprd-/- mice displayed autistic-like behaviors and no learning and memory impairments or anxiety.ConclusionsThese results indicate that loss of Ptprd has long-lasting effects on cortical neuron number and synaptic function that may aberrantly impact ASD-like behaviors.

Neural conditional ablation of the protein tyrosine phosphatase receptor Delta PTPRD impairs gliogenesis in the developing mouse brain cortex.

Neurodevelopmental disorders are characterized by alterations in the development of the cerebral cortex, including aberrant changes in the number and function of neural cells. Although neurogenesis is one of the most studied cellular processes in these pathologies, little evidence is known about glial development. Genetic association studies have identified several genes associated with neurodevelopmental disorders. Indeed, variations in the PTPRD gene have been associated with numerous brain disorders, including autism spectrum disorder, restless leg syndrome, and schizophrenia. We previously demonstrated that constitutive loss of PTPRD expression induces significant alterations in cortical neurogenesis, promoting an increase in intermediate progenitors and neurons in mice. However, its role in gliogenesis has not been evaluated. To assess this, we developed a conditional knockout mouse model lacking PTPRD expression in telencephalon cells. Here, we found that the lack of PTPRD in the mouse cortex reduces glial precursors, astrocytes, and oligodendrocytes. According to our results, this decrease in gliogenesis resulted from a reduced number of radial glia cells at gliogenesis onset and a lower gliogenic potential in cortical neural precursors due to less activation of the JAK/STAT pathway and reduced expression of gliogenic genes. Our study shows PTPRD as a regulator of the glial/neuronal balance during cortical neurodevelopment and highlights the importance of studying glial development to understand the etiology of neurodevelopmental diseases.

MiR-324-5p/PTPRD/CEBPD axis promotes papillary thyroid carcinoma progression via microenvironment alteration

ABSTRACTMiR-324-5p is overexpressed in papillary thyroid carcinoma (PTC) with lymph node metastasis and promotes malignant phenotypes of KTC-1 cell line. However, the detailed regulatory mechanism remains unknown. Tumor microenvironment plays a key role in tumor progression. CCAAT enhancer-binding protein delta (CEBPD) is important in immune and inflammatory responses. In this study, we investigated the interaction between miR-324-5p/PTPRD/CEBPD axis and tumor microenvironment in PTC progression. K1 and KTC-1 were transfected by lenti-CEBPD or CEBPD-sh vectors. Supernatant from different groups was harvested and added into culture media of human macrophages and HUVEC. Cell viability, colony formation, invasive and migrated cell number, and gap closure rate were elevated in lenti-CEBPD group. Compared with the control, supernatant from lenti-CEBPD group contained more abundant levels of VEGF and IL-4/IL-13, which, respectively, induced higher HUVEC invasion/migration rates and more obvious M2 marker (CD206) and genes (PPAR-γ and MRC-1) expression in macrophages. By means of luciferase reporter assay and gene manipulation, we identified that CEBPD was negatively regulated in PTC by protein tyrosine phosphatase receptor delta (PTPRD) which was the target of miR-324-5p. CEBPD-shRNA was also proved to reverse the effect of PTPRD-sh1 or miR-324-5p mimic on IL-4/IL-13 expression and HUVEC invasion. These results suggested that miR-324-5p/PTPRD/CEBPD axis was involved in the progression of PTC by inducing HUVEC invasion/migration and macrophage M2 polarization via VEGF and IL4/IL13, respectively.

MiR-135a-5p-mediated downregulation of protein tyrosine phosphatase receptor delta is a candidate driver of HCV-associated hepatocarcinogenesis

Background and aimsHCV 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,...

The Coding Genome of Nodal Marginal Zone Lymphoma Reveals Recurrent Molecular Alterations of PTPRD and Other Jak/Stat Signaling Genes

Background. Nodal marginal zone lymphoma (NMZL) is one of the few B-cell tumors still remaining orphan of cancer gene lesions. By combining whole exome sequencing (WES), deep sequencing of tumor-related genes, high resolution SNP array and RNAseq, here we aim at characterizing the coding genome of NMZL and at disclosing the pathways that are molecularly deregulated in this lymphoma.Methods. The study was based on 35 NMZL (tumor representation >70%) with a diagnosis confirmed by: i) pathological revision of lymph node histology; and ii) lack of clinico-radiological evidence of extranodal or splenic disease either at diagnosis or during follow-up. Consistent with NMZL, the cases investigated: i) lacked CD5, CD10 and cyclin D1 expression, 7q deletion, t(11;14), t(14;18), t(11;18) and t(1;14) translocations; and ii) recurrently harbored +3 (14%), +12 (14%) and preferential usage of the IGHV4-34 gene (17%). WES (HiSeq 2500, Illumina; mean coverage per sample: 38x-114x) and high density SNP array (Cytoscan HD, Affymetrix) of tumor/normal DNA pairs from 18 discovery NMZL identified 557 non-synonymous somatic mutations (average: 30.9/case) affecting 504 genes and 61 copy number abnormalities (CNA) (average 3.4/case). To further characterize mutation recurrence, the 504 discovered genes were investigated in an independent validation panel of 17 NMZL by targeted sequencing of tumor/normal DNA pairs (MiSeq; target region: 1.6 Mb; mean coverage per sample: 171x-386x). The 17 validation NMZL were also assessed for CNA by high density SNP arrays. RNAseq of 11 discovery NMZL did not identify any recurrent gene fusion. Results. By compiling the results of WES and high resolution SNP array, 39 genes were recurrently affected in >3/35 (9%) NMZL by mutations (n=30 genes) or focal CNA (n=9 genes). Among these, MLL2 (34%), PTPRD (20%) and NOTCH2 (20%) were most frequently mutated. Overall, recurrently mutated genes pointed to the molecular deregulation of specific programs in NMZL, namely JAK/STAT, NOTCH, NF-κB and toll-like receptor (TLR) signaling, cell cycle, chromatin remodeling/transcriptional regulation and immune escape (Fig. 1A). JAK/STAT signaling was targeted by mutually exclusive lesions in 43% of NMZL, and the protein tyrosine phosphatase receptor delta (PTPRD) tumor suppressor was the most frequently affected gene of this system in 20% of NMZL (Fig. 1B-E). PTPRD inhibits JAK/STAT signaling through the dephosphorylation of active p-STAT3. PTPRD lesions in NMZL were represented by somatic mutations that truncated or modified the tyrosine phosphatase domain, as well as deletions of the entire gene locus, including focal and biallelic losses (Fig. 1B-C). Interrogation of institutional and public genomic datasets revealed that PTPRD mutations are specific for NMZL, being rare or absent in other mature B-cell tumors, including splenic marginal zone lymphoma (Fig. 1D). Other JAK/STAT signaling genes affected in NMZL were JAK2, CXCR4 (6%), PTPN2, JAK3, STAT2, SH2B3 and CUL3 (3%) (Fig. 1E). NF-kB signaling was altered in 54% of NMZL by lesions of TNFAIP3 (14%), BCL10, REL (11%), CARD11 (9%), TRAF3 and BIRC3 (6%). NOTCH signaling was targeted in 40% of NMZL by mutations that alternatively involved NOTCH2 (20%), SPEN (11%), RBPJL (6%), FBXW7, DTX1, ITCH and MAML2 (3%). TLR signaling was targeted in 17% of NMZL, including mutations of MYD88 (9%), IRAK1BP1, PELI2 and SEMP6 (3%). Several cell cycle genes were molecularly deregulated in 43% of NMZL, including CDKN2A, PARK2, PARKG (9%), CDC16, CDCA2 (6%), CCNA1, CCNT2, CDK5, CDK13, CDK20, BTG2, HECA and PLK2 (3%). Most (71%) NMZL harbored genetic lesions affecting epigenetic modifiers (MLL2: 34%; CREBBP: 9%; EP300: 6%; TRRAP: 6%), histones (20%) or transcriptional co-repressors (TBL1XR1: 14%; ARID1A: 14%; RCOR1: 11%; NCOR2: 9%, ARID1B: 9%). Finally, the TNFRSF14 and FAS genes, involved in T cell-mediated tumor surveillance, were disrupted by mutations and/or deletions in 17% and 14% NMZL, respectively.Conclusions. A number of actionable cellular programs are molecularly deregulated in NMZL, including JAK/STAT, NOTCH, NF-κB and TLR signaling, cell cycle and chromatin remodeling. PTPRD lesions are among the most recurrent alterations in NMZL and appear to be specific for this lymphoma type across mature B-cell tumors. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Anti-EGFR therapeutic efficacy correlates directly with inhibition of STAT3 activity

Several agents targeting the epidermal growth factor receptor (EGFR) have been FDA-approved to treat cancer patients with varying tumor types including metastatic colorectal cancer. Many patients treated with anti-EGFR therapy however do not respond and those that do initially respond often acquire resistance. Here we show a clear correlation between the efficacy of anti-EGFR inhibitors with their ability to inhibit STAT3 activity in A431 epidermoid carcinoma cells and in a series of wt K-RAS expressing human colon cancer cell lines. Furthermore, the ability of cetuximab to inhibit growth also correlated with its ability to inhibit STAT3 activity in tumor xenograft animal studies. In addition, stable knockdown of the STAT3 phosphatase, protein tyrosine phosphatase receptor delta (PTPRD) resulted in enhanced STAT3 activity and subsequent resistance to cetuximab in DIFI colon carcinoma cells. This resistance could be reversed by STAT3 inhibition. Finally, HN5 cells with acquired resistance to the EGFR tyrosine kinase inhibitor, AG1478 displayed greater STAT3 activity than the HN5 control cell line. These AG1478-refractory HN5 cells were re-sensitized to AG1478, cetuximab and erlotinib when co-treated with a STAT3 inhibitor. Taken together, our current data indicates a key role of STAT3 activity in promoting resistance to anti-EGFR therapy and suggests that anti-EGFR therapy in combination with inhibitors that block STAT3 may provide therapeutic benefit for patients with mCRC and other EGFR driven tumor types.

Polymorphism in protein tyrosine phosphatase receptor delta is associated with the risk of clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is a common urological malignancy. Our previous study has indicated that the protein tyrosine phosphatase receptor type delta (PTPRD) gene may play a role. To determine the effect of PTPRD genetic polymorphisms on ccRCC occurrence and progression, a total of 377 ccRCC cases and 754 matched controls were enrolled in the study. DNA sequencing and genotyping, and immunohistochemistry were conducted to test the associations of genotypes with ccRCC risk and PTPRD expression level in somatic tissues. The C allele of PTPRD rs2279776 was associated with a higher risk of ccRCC (per allele OR=1.23, P=0.03). Patients without distant metastasis at the time of surgery were followed for a median of 33.1months. Overall survival was not different between different rs2279776 genotype groups (P=0.30). The C allele was associated with a higher percentage of negative immunostaining in adjacent normal renal tissues (P=0.02). PTPRD rs2279776 SNP may be a novel genetic risk factor of ccRCC.

Protein tyrosine phosphatase receptor delta acts as a neuroblastoma tumor suppressor by destabilizing the aurora kinase a oncogene

BackgroundProtein tyrosine phosphatase receptor delta (PTPRD) is a member of a large family of protein tyrosine phosphatases which negatively regulate tyrosine phosphorylation. Neuroblastoma is a major childhood cancer arising from precursor cells of the sympathetic nervous system which is known to acquire deletions and alterations in the expression patterns of PTPRD, indicating a potential tumor suppressor function for this gene. The molecular mechanism, however, by which PTPRD renders a tumor suppressor effect in neuroblastoma is unknown.ResultsAs a molecular mechanism, we demonstrate that PTPRD interacts with aurora kinase A (AURKA), an oncogenic protein that is over-expressed in multiple forms of cancer, including neuroblastoma. Ectopic up-regulation of PTPRD in neuroblastoma dephosphorylates tyrosine residues in AURKA resulting in a destabilization of this protein culminating in interfering with one of AURKA's primary functions in neuroblastoma, the stabilization of MYCN protein, the gene of which is amplified in approximately 25 to 30% of high risk neuroblastoma.ConclusionsPTPRD has a tumor suppressor function in neuroblastoma through AURKA dephosphorylation and destabilization and a downstream destabilization of MYCN protein, representing a novel mechanism for the function of PTPRD in neuroblastoma.

Clinical features of renal cell carcinoma (RCC) found in 110 nephrectomized Japanese, of which 24 (22%) RCC cases showed 31 double or triple cancers

The causes of renal cell carcinoma (RCC) were investigated in 115 nephrectomized Japanese. Among them, 110 nephrectomized Japanese had RCC as follows: 86 clear cell RCC, 8 papillary RCC, 8 chromophobe RCC, 7 dialytic–multicystic RCC, and 1 liposarcoma, while 5 nephrectomized Japanese had benign renal tumors of oncocytoma (1), angiomyolipoma (2), and hemangioma (2). In the eight chromophobe RCC, three cases that resulted in death involved medullary RCC showing extensive oncogenic features. Double or triple cancers were found in 17 clear cell RCC, 5 papillary RCC, 1 chromophobe RCC, and 1 dialytic–multicystic RCC. Among 31 non-RCC found in 24 RCC cases, 23(74%) non-RCC were removed prenephrectomy. Prenephrectomy adenocarcinoma and postnephrectomy squamous cell carcinoma were their characteristic findings. Compared with those of clear cell RCC, double (triple) cancers of papillary RCC showed more aggressive malignancy. One clear cell RCC had triple cancer of thymoma and rectum cancer. One chromophobe RCC developed thymoma, while one oncocytoma had insulinoma >10 years before. A patient in his sixties with clear cell RCC, who had a past history of pneumothorax, had developed adenocarcinoma of colon polyps and liver adenocarcinoma almost at the same time as triple cancer. His lactate dehydrogenase (LDH) levels were under 300 IU/l. He was suspected of having Birt–Hogg–Dube syndrome. One patient with papillary RCC of Paget’s disease of the bone developed colon polyp adenocarcinoma, osteosarcoma, and additionally exhibited p97/valosin-containing protein downregulation in his sixties. His LHD was increased to 4,289 IU/l with cell lysis reactions. His radical nephrectomy accompanied by adrenalectomy reinforced clinical manifestations of p97 downregulation. For p97 functions, the kidney and adrenal gland had important roles. It was concluded that oxygen stress was stronger in RCC, especially in papillary RCC. Nonsense mutations of protein tyrosine phosphatase receptor delta might be one cause of double (triple) cancers in RCC.

D9S168 microsatellite alteration predicts a poor prognosis in patients with clear cell renal cell carcinoma and correlates with the down‐regulation of protein tyrosine phosphatase receptor delta

The role of microsatellite alterations in surgically excised tumors in predicting the prognosis of patients with clear cell renal cell carcinoma (ccRCC) remains largely unknown. Specimens from 93 patients with sporadic ccRCC were used to screen microsatellite alterations using 12 markers on chromosomes 3p, 9p, and 14q according to disease stage. Survival was evaluated by using the Kaplan-Meier method and Cox regression analysis. The expression of targeted genes was examined using quantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry, respectively. Of the markers that were screened, D9S168 (9p23-22) had the highest frequency (36.9%) of microsatellite alteration in the specimens. D9S168 alterations were frequent in high-stage tumors. Seventy-eight patients who had ccRCC without distant metastasis at the time of surgery were followed for a median of 31.7 months. Overall survival and disease-free survival were poorer for patients with D9S168 alteration than for those without alteration (P < .001 for each; log-rank test). Cox regression analysis indicated that D9S168 alteration was associated independently with cancer-related death (P = .010). The D9S168 alteration, which was located at the 5'-untranslated region of a gene that encodes protein tyrosine phosphatase (PTP) receptor delta (PTPRD), was associated significantly with low expression of PTPRD at the messenger RNA level (P = .001). Immunohistochemistry revealed that the expression of PTPRD was strong in normal kidney proximal tubular epithelial cells, from which ccRCC originated, and was greatly down-regulated in ccRCC (P < .001; Wilcoxon rank-sum test). D9S168 microsatellite alteration in tumors predicted a poor prognosis for patients with ccRCC after curative nephrectomy. The authors concluded that PTPRD is a putative tumor suppressor in ccRCC and has therapeutic potential.