Protein Tyrosine Phosphatase Non-receptor Type Research Articles

PTPN3 Could Βe a Therapeutic Target of Pancreatic Cancer.

Recently, protein tyrosine phosphatase non-receptor type 3 (PTPN3) has gained attention. However, the role of PTPN3 in cancer has not been fully elucidated. In the present study, we analyzed the role of PTPN3 in pancreatic cancer and investigated whether PTPN3 could be a new therapeutic target for pancreatic cancer. Two pancreatic ductal adenocarcinoma (PDAC) cell lines were used as target cells. Cell proliferation was investigated using cell counting and a xenograft mouse model. Migration and invasion were analyzed using Transwell inserts. Activation-related signaling molecules were examined by western blotting. PTPN3 contributes to the proliferation, migration, and invasion of PDAC cells in vitro. PTPN3 promotes tumor growth in a mouse xenograft model, an action mediated partially through the MAPK pathway. PTPN3 could be a new therapeutic target for pancreatic cancer.

Polymorphism of protein tyrosine phosphatase non-receptor type 22 and protein arginine deiminase 4 gene among Ghanaian rheumatoid arthritis patients: A case-control study.

Rheumatoid arthritis (RA) is an autoimmune disease which affects millions of lives globally characterized by chronic inflammation in the joints of the body. There is no known cause for RA; however, genetic predisposition has been associated with its occurrence. The association between genetic predisposition and RA has been reported largely among Caucasians and Asians. However, few studies with limited data have reported genome-wide association studies of RA in Africa, especially in Ghana. In addition, there is genetic heterogeneity that exists geographically among different populations. This study therefore investigated the association of protein arginine deiminase type 4 (PAD4) and protein tyrosine phosphatase non-receptor type 22 (PTPN22) single nucleotide polymorphisms with susceptibility of RA among Ghanaians. This case-control study included 75 RA patients and 75 healthy controls from the Komfo Anokye Teaching Hospital in Ghana. Validated questionnaires were used to obtain demographic data, and blood samples were collected and processed for DNA and polymerase chain reaction analysis. Statistical analysis was done using SPSS version 25.0. PTPN22 demonstrated a 100% minor allele frequency (GG) in both cases and healthy controls; however, an association could not be made for PTPN22 polymorphism with susceptibility of RA when comparing cases to controls. The homozygous minor allele (GG) of PAD4 was absent in the population. PAD4 polymorphism was absent, while PTPN22 was present in the Ghanaian population. The association between PTPN22 (rs2476601) and PAD4 (rs2240340) with RA susceptibility could not be established, thus may not contribute as risk factors for RA in the Ghanaian population.

Loss of PTPN2 Activity Alters Iron Handling Protein Expression in IBD Patients and Causes Iron Deficiency in Mice

BackgroundAnemia is the most common extraintestinal complication of inflammatory bowel disease (IBD) and is a risk factor for Crohn’s disease (CD) onset. Iron deficiency is the most common cause of anemia in IBD; however, the mechanisms involved are poorly understood. Here, we investigated the role of the IBD risk gene, protein tyrosine phosphatase non‐receptor type 2 (PTPN2), in regulating iron homeostasis.MethodsProteomic analyses were performed on serum from IBD patients genotyped for the IBD‐associated loss‐of‐function rs1893217 PTPN2variant (n=10/genotype). Constitutive Ptpn2 wild type (WT), heterozygous (Het), and knockout (KO) 3‐week‐old mice were analyzed for serum iron content, liver non‐heme iron and liver expression of the iron regulatory hormone, hepcidin (Hamp1). Protein and RNA from duodenal epithelial cells (DECs) were assayed by western blotting and qPCR. Localization of the brush border ferrous iron transporter, DMT1, in duodenal tissue was determined by immunohistochemistry (IHC).ResultsIron homeostasis genes, the iron carrier transferrin (TF) and the transferrin receptor (TFRC), were reduced (‐log p‐value = 10.7) in CD patients with the PTPN2 risk variant. Ptpn2‐KO mice had reduced i) serum iron (p<0.001; n=11); ii) serum TF saturation (p<0.01; n=9); and iii) liver non‐heme iron levels (p<0.01; n=10), vs. Ptpn2‐WT and Het mice. This indicated that PTPN2 loss decreased serum and liver iron storage. Moreover, Ptpn2‐KO mice had reduced liver expression of Hamp1 (p<0.01; n=7), likely suppressed by low serum iron. DEC gene expression of ferritin (Fth1), an intracellular iron storage molecule, was reduced (p=0.048; n=5) while Tfrc1, a mediator of basolateral cellular iron uptake, was significantly increased (p=0.0048; n=6) in Ptpn2‐KO mice. Reduced FTH1 expression (p=0.007; n=12) in DECs of Ptpn2‐KO mice was confirmed by western blot, indicating reduced intracellular iron storage. DMT1 expression was unchanged (n=6), whereas IHC showed reduced apical membrane DMT1 in duodenal epithelium of Ptpn2‐KO mice (n=6), suggesting a possible mechanism of impaired intestinal non‐heme iron uptake.ConclusionsCD patients with the PTPN2 loss‐of‐function rs1893217 SNP display alterations in serum iron handling proteins. Loss of PTPN2 activity in mice causes features of anemia including iron deficiency associated with mislocalization of the duodenal transporter DMT1. These findings identify a major role for PTPN2 in regulating iron homeostasis.

Transthyretin-induced increase in circ_0007411 represses neovascularization of human retinal microvascular endothelial cells in hyperglycemia via the miR-548m/PTPN12/SKP1/EGFR pathway.

BackgroundTo investigate the mechanism of transthyretin (TTR) induced high expression of circ_0007411 and its parent gene, protein tyrosine phosphatase nonreceptor type 12 (PTPN12) in human retinal microvascular endothelial cells (hRECs) cultivated under high glucose condition.MethodsThe levels of PTPN12, circ_0007411, miR-548m, S-phase kinase associated protein 1 (SKP1) and epidermal growth factor receptor (EGFR) were detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The direct interaction between circ_0007411/PTPN12 and miR-548m was investigated via Dual-luciferase reporter assay. The physiological characterization of hRECs was investigated through Cell Counting Kit-8 (CCK-8), 5-Ethynyl-2'-deoxyuridine (EdU) labelling, Transwell, flow cytometry (FCM), wound healing, and tube formation assays. Co-immunoprecipitation (Co-IP) was used to detect the interaction between PTPN12 and SKP1. The function of PTPN12 against diabetic retinopathy (DR) was studied in streptozotocin (STZ) induced DR C57BL/6 mice.ResultsThe levels of circ_0007411 was increased in hRECs in hyperglycemia with the induction of TTR. The overexpressed circ_0007411 could significantly enhance the level of PTPN12 and repress that of miR-548m, and it could enhance apoptosis and prohibit the proliferation, migration, and tube formation of hRECs. miR-548m mimics enhanced the proliferation, migration, and tube formation of hRECs by reducing the expression level of PTPN12 and promoting that of EGFR, whereas circ_0007411 rescued it. The direct binding of PTPN12 and SKP1 was confirmed by Co-IP. Additionally, the anti-neovascularization function of PTPN12 was confirmed in a STZ-induced mouse model of DR.ConclusionsIn hyperglycemia, the TTR-induced increase in circ_0007411 could repress retinal neovascularization via the miR-548m/PTPN12/SKP1/EGFR pathway.

Prolonged diet-induced obesity modifies DNA methylation and gene expression in the hippocampus

Obesity and age independently have negative effects on the brain, increasing the risk of neurodegenerative events. How these events synergize to increase disease susceptibility remains poorly understood. To better understand the epigenetic implications of poor diet with increased age, we sought to determine CpG methylation changes in the dorsal hippocampus attributable to age and/or diet-induced obesity. Male C57BL/6J mice were fed either normal chow or an obesogenic diet until six or 14 months of age. Hippocampus was analyzed by Reduced Representation Bisulfite Sequencing. In total, 107 differentially methylated regions (DMRs) were identified across all four conditions; older obese mice accounted for 63% of those DMRs. Gene ontology analysis showed two affected pathways, nervous system development and regulation of multicellular organismal process, in older obese mice only. From the RRBS results, five genes were selected for qPCR quantification: Bridging Integrator 1 (BIN1), Histone Deacetylase 5 (HDAC5), Folliculin Interacting Protein 2 (FNIP2), Proline, Glutamate and Leucine Rich Protein 1 (PELP1), and Protein Tyrosine Phosphatase Non-Receptor Type 1 (PTPN1). Generally, DMR changes aligned with mRNA expression changes in BIN1, HDAC5, FNIP2, PELP1, and PTPN1. Notably BIN1 decreased and HDAC5 increased due to obesity and age. In summary, obesity interacts with aging to significantly affect the hippocampal methylome, changing the expression of genes implicated in neurodegeneration and metabolism.

SHP2/SPI1axis promotes glycolysis and the inflammatory response of macrophages in Helicobacter pylori-induced pediatric gastritis.

Macrophages, as innate immune cells, were reported to participate in the pathogenesis of Helicobacter pylori (H. pylori)-induced gastritis. However, the role and mechanism of macrophage dysfunction in H.pylori-associated pediatric gastritis remain unclear. An RNA-sequencing assay was used to examine the differential gene expression in normal gastric antrum, non-H.pylori-infected tissue, and H.pylori-infected pediatric gastritis tissue. qPCR assays were applied to verify the expression of target genes. HE staining was performed to identify the occurrence of inflammation in the normal gastric antrum, non-H.pylori-infected tissue, and H.pylori-infected pediatric gastritis tissue. Western blotting was used to measure the expression of SHP2 in pediatric gastritis tissue. The metabolic profile of macrophages was determined via Seahorse metabolic analysis. Flow cytometry analysis was used to examine the level of reactive oxygen species (ROS). We found that H.pylori -infected gastritis tissue exhibited many differentially expressed genes (DEGs) compared to gastritis tissue without H.pylori infection. Moreover, H.pylori -infected gastritis tissue showed many DEGs annotated with an overactive immune response. We identified that tyrosine-protein phosphatase nonreceptor type 11 (PTPN11), which encodes SHP2, was significantly increased in macrophages of H.pylori -infected gastritis tissue. Furthermore, we revealed that SHP2 could activate the glycolytic function of macrophages to promote H.pylori -induced inflammation. The transcription factor SPI1 , as the downstream molecule of SHP2, could be responsible for the regulation of metabolism-associated gene expression and inflammation. Our study illustrated the molecular landscape of H.pylori-infected gastritis tissue in children and suggested that the SHP2/SPI1axis could be a novel therapeutic target in H.pylori-induced pediatric gastritis.

Proteomic Profiling and Functional Analysis of B Cell-Derived Exosomes upon Pneumocystis Infection.

Pneumocystis is a life-threatening fungal pathogen that frequently causes fatal pneumonia (PCP) in immunocompromised individuals. Recently, B cells have been reported to play a crucial role in the pathogenesis of PCP through producing antibodies and activating CD4+ T cell response. Exosomes are nanoscale small extracellular vesicles abundant with protein cargo and can mediate immune response during infectious disease. In this study, using tandem mass tag-based quantitative proteomics coupled with bioinformatic analysis, we attempted to characterize exosomes derived from B lymphocytes in response to PCP. Several proteins were verified by parallel reaction monitoring (PRM) analysis. Also, the effects of B cell exosomes on CD4+ T cell response and phagocytic function of macrophages were clarified. Briefly, 1701 proteins were identified from B cell exosomes, and the majority of them were reported in Vesiclepedia. A total of 51 differentially expressed proteins of B cell exosomes were found in response to PCP. They were mainly associated with immune response and transcription regulation. PRM analysis confirmed the significantly changed levels of histone H1.3, vimentin, and tyrosine-protein phosphatase nonreceptor type 6 (PTPN6). Moreover, a functional study revealed the proinflammatory profile of B cell exosomes on CD4+ T cell response in PCP. Taken together, our results suggest the involvement of exosomes derived from B cells in cell-to-cell communication, providing new information on the function of B cells in response to PCP.

PTPN18 Stimulates the Development of Ovarian Cancer by Activating the PI3K/AKT Signaling.

Objective To illustrate the functions of protein tyrosine phosphatase nonreceptor type 18 (PTPN18) in the progression of ovarian cancer and the potential molecular mechanism. Methods Differential PTPN18 expression in ovarian cancer samples was determined. Following PTPN18 knockdown, changes in proliferation and migration in ovarian cancer cells were detected. Nude mice with ovarian cancer were used to uncover the effects of PTPN18 on ovarian cancer growth in vivo. Results PTPN18 was significantly upregulated in ovarian cancer samples and linked to pathological staging and metastasis rate. PTPN18 displayed prognostic and diagnostic potentials in ovarian cancer. Knockdown of PTPN18 and treatment of the PI3K inhibitor could inhibit proliferative and migratory abilities in ovarian cancer cells. Moreover, PTPN18 was capable of inactivating PI3K/AKT signaling. In vivo knockdown of PTPN18 suppressed ovarian cancer growth in nude mice. Conclusions PTPN18 is upregulated in ovarian cancer, which stimulates the malignant development by activating PI3K/AKT signaling. The PTPN18 level is also associated with pathological staging and metastasis in ovarian cancer patients, which may be utilized as a hallmark predicting the malignant level.

Downregulation of secreted frizzled-related protein 4 inhibits hypoxia/reoxygenation injury in diabetic cardiomyocytes by protein tyrosine phosphatase nonreceptor type 12

ABSTRACT Myocardial ischemia-reperfusion injury in diabetic patients leads to an increased incidence of complications and mortality. Secreted frizzled-related protein 4 (SFRP4) plays a critical role in diabetic myocardial ischemia-reperfusion. This paper aims to uncover the underlying mechanisms of SFRP4 in hypoxia/reoxygenation (H/R) injury of diabetic myocardial cells. An in vitro ischemia/reperfusion (I/R) injury model was established using high glucose-induced H9c2 cardiomyocytes. Expression of SFRP4 was detected by real-time reverse transcriptase-polymerase chain reaction and Western blotting. After transfection of SFRP4, the binding of SFRP4 to protein tyrosine phosphatase nonreceptor type 12 (PTPN12) was predicted by database and verified by co-immunoprecipitation assay. P13 K/AKT protein levels were examined by Western blotting. PTPN12 levels were tested by RT-qPCR and Western blotting, cell viability by Cell Counting Kit-8, lactose dehydrogenase kit, terminal dUTP nick-end labeling assay, and cell inflammation and oxidative stress by Western blotting and enzyme linked immunosorbent assay. After overexpression of PTPN12, the experiments for cell viability, inflammation and oxidative stress were repeated once more. SFRP4 expression was upregulated in a high-glucose-stimulated H/R cardiomyocyte model. The interference of SFRP4 promoted cell viability, inhibited the inflammatory and oxidative stress response of H/R cardiomyocytes induced by high glucose. SFRP4 interacted with PTPN12 and inhibited the PI3K/AKT signaling pathway. PTPN12 overexpression reversed the inhibitory effect of sh-SFRP4 on H/R cardiomyocyte damage induced by high glucose. Downregulation of SFRP4 inhibited H/R cell damage in diabetic cardiomyocytes by binding to PTPN12.

The tyrosine phosphatase PTPN14 inhibits the activation of STAT3 in PEDV infected Vero cells

Protein tyrosine phosphatase non-receptor type 14 (PTPN14) is a member of the protein tyrosine phosphatase (PTP) family which is a potential tumor suppressor. PTPs modulate the cellular level of tyrosine phosphorylation under normal and pathological conditions. Porcine epidemic diarrhea virus (PEDV) is one of the most important pathogens in the swine industry. Our previous membrane proteomics results showed that PTPN14 was markedly upregulated in PEDV-infected Vero cells. However, its biological roles in PEDV infection have not yet been investigated. In this study, we reported PTPN14 functions as a novel regulator of signal transducer and activator of transcription 3 (STAT3) phosphorylation during PEDV infection. Firstly, PTPN14 was markedly upregulated in PEDV-infected Vero cells with the decrease of STAT3 phosphorylation. Knockdown of PTPN14 or phosphatase inhibitor treatment promoted PEDV proliferation and increased the phosphorylation of STAT3 in Vero cells. On the contrary, overexpression of PTPN14 inhibits viral infection in Vero cells. Moreover, dephosphorylation of STAT3 by PTPN14 might occur in the cytoplasm but not in nucleus. Collectively, our results indicate that PTPN14 plays a negative role in regulating STAT3 activation in PEDV infected Vero cells and demonstrate another layer of regulation in PEDV infection.

Inhibiting microRNA-142–5p improves learning and memory in Alzheimer’s disease rats via targeted regulation of the PTPN1-mediated Akt pathway

ObjectiveMicroRNAs (miRNAs) have been recognized as possible biomarkers for Alzheimer’s disease (AD). MiR-142–5p has been reported to be abnormally expressed in brain tissues. However, the role of miR-142–5p in AD pathogenesis keeps unclear. This study aimed to investigate the effect of miR-142–5p on the learning and memory of AD rats via regulation of protein tyrosine phosphatase nonreceptor type 1 (PTPN1)-mediated protein kinase B (Akt) pathway. MethodsThe AD model was established by injection of Aβ1–42 oligomer once into the lateral ventricle of rats, and the spatial learning and memory ability of rats was measured. AD rats were injected with miR-142–5p or PTPN1 vectors to explore their functions in inflammation, Aβ, p-tau protein, apoptosis in brain tissues, and the effects on Akt pathway. The targeting relationship between miR-142–5p and PTPN1 was detected. ResultsOverexpressed miR-142–5p, down-regulated PTPN1 and inactivated Akt pathway were exhibited in AD. MiR-142–5p targeted PTPN1 to mediate Akt pathway. Reduced miR-142–5p and elevated PTPN1 improved the behavior of AD rats. MiR-142–5p targeted PTPN1 to effectively inhibit Aβ formation and abnormal phosphorylation of p-tau protein, suppress the inflammation in the brain tissues of AD rat, and improve the survival rate of brain tissue cells. MiR-142–5p regulated PTPN1 to activate the Akt pathway, further inhibiting the apoptosis of brain neurons in AD rats. ConclusionDown-regulating miR-142–5p targets PTPN1 to activate Akt pathway, thus improving the learning and memory of AD rats and playing an anti-AD role.

Association of SNPs within PTPN3 gene with wool production and growth traits in a dual-purpose sheep population

Protein tyrosine phosphatase non-receptor type 3 (PTPN3), a member of the membrane-associated non-receptor protein tyrosine phosphatase (PTP) family, plays significant roles in the cytoplasm and affects the development and growth of skin and hair. A recent study identified the PTPN3 as the potential gene related to sheep wool quality. To detect single-nucleotide polymorphisms (SNPs) of PTPN3 and elucidate its association with wool production and growth traits in fine wool sheep a total of 644 healthy SG (South African mutton merino♂ × Gansu alpine fine-wool sheep♀, SG) and SSG (South African mutton merino♂ × SG♀, SSG) hybrid sheep were selected. Pooled-DNA sequencing and SNPscan methods were used to scan and genotype SNPs within PTPN3. Association analyses between SNPs and wool production and growth traits were implemented. Consequently, the results revealed that PTPN3 has six SNPs (two missense mutations, one synonymous mutation, and three intron mutations), of which four loci (SNP2, SNP3, SNP4, and SNP5) were significantly positively correlated with growth and wool traits (p < 0.05). SNP4 was significantly (p < 0.05) linked with thigh wool length, and SNP6 was significantly (p < 0.05) associated with abdomen wool length. Moreover, one strongly linked SNP block was identified to be correlated with wool production and growth traits (body weight and body size). The significant SNPs founded by this study could serve as useful genetic markers for breeding fine-wool sheep.®

YAP1 activation by human papillomavirus E7 promotes basal cell identity in squamous epithelia.

Persistent human papillomavirus (HPV) infection of stratified squamous epithelial cells causes nearly 5% of cancer cases worldwide. HPV-positive oropharyngeal cancers harbor few mutations in the Hippo signaling pathway compared to HPV-negative cancers at the same anatomical site, prompting the hypothesis that an HPV-encoded protein inactivates the Hippo pathway and activates the Hippo effector yes-associated protein (YAP1). The HPV E7 oncoprotein is required for HPV infection and for HPV-mediated oncogenic transformation. We investigated the effects of HPV oncoproteins on YAP1 and found that E7 activates YAP1, promoting YAP1 nuclear localization in basal epithelial cells. YAP1 activation by HPV E7 required that E7 binds and degrades the tumor suppressor protein tyrosine phosphatase non-receptor type 14 (PTPN14). E7 required YAP1 transcriptional activity to extend the lifespan of primary keratinocytes, indicating that YAP1 activation contributes to E7 carcinogenic activity. Maintaining infection in basal cells is critical for HPV persistence, and here we demonstrate that YAP1 activation causes HPV E7 expressing cells to be retained in the basal compartment of stratified epithelia. We propose that YAP1 activation resulting from PTPN14 inactivation is an essential, targetable activity of the HPV E7 oncoprotein relevant to HPV infection and carcinogenesis.

Abstract OT2-28-01: A phase 2 study of sitravatinib in metastatic, pre-treated, triple negative breast cancer, NCT # 04123704

Abstract Background:Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer, disproportionally affecting African American and Hispanic patients, and germline BRCA1/2 mutation carriers. Prognosis of relapsed, metastatic disease is extremely poor and effective well-tolerated therapies are urgently needed. Our collaborators have discovered that TNBCs often lose feedback control of receptor tyrosine kinases (RTKs) including PDGFR and MET, locking these receptors in a chronically active state. These receptors share a common negative regulator called Protein Tyrosine Phosphatase, Non-Receptor Type 12 (PTPN12). Baylor investigators have shown that PTPN12- deficient TNBCs may be responsive to combined RTK inhibition. Sitravatinib is a spectrum selective RTK inhibitor that has shown strong antitumor activity in patient derived xenografts (PDXs) of TNBC with low levels of PTPN12. We have therefore designed a phase II, multi-institution, two cohort trials to evaluate the efficacy of sitravatinib in patients with metastatic TNBC (mTNBC). Methods: Patients with diagnosis of mTNBC who have received at least one line of chemotherapy +/- atezolizumab for advanced disease would be considered for enrollment. Patients would need to have tissue from metastatic site available for evaluation or agree to undergo biopsy if banked tumor tissue is not available. Sitravatinib at 100 mg daily, the recommended phase 2 dose for sitravatinib monotherapy, will be started at the initiation of the study and continued until progression or unacceptable toxicity. The study will employ a modified optimal Simon’s two stage design. Patients will be recruited into two cohorts: PTPN12 low or PTPN12 high/normal cohorts simultaneously and independently. Seven patients will be enrolled to each arm during the first stage. After the first stage, depending on the observed number of responses, the study will proceed to the 2nd stage. The primary endpoint is progression-free survival status at 24 weeks (PFS24). Current Trial status: The trial is funded by Mirati Therapeutics and opened to enrollment at Dan L Duncan Comprehensive Cancer Center (DLDCCC) clinics as of 6/8/21. Trial is due to open at UT Southwestern Dallas by 11/2021. The correlative science is funded by an institutional SPORE grant. Conclusion: This trial aims to show that sitravatinib is safe and to investigate whether it could be a treatment option in mTNBC. Citation Format: Maryam Nemati Shafaee, Kristen Otte, Nicholas J Neill, Kent C Osborne, Thomas F Westbrook, Susan Hilseneck, Matthew J Ellis. A phase 2 study of sitravatinib in metastatic, pre-treated, triple negative breast cancer, NCT # 04123704 [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr OT2-28-01.

Circ_AKT3 knockdown suppresses cisplatin resistance in gastric cancer.

BackgroundCircular RNAs (circRNAs) are associated with cisplatin resistance in gastric cancer (GC). This study aims to explore the role of circRNA AKT serine/threonine kinase 3 (circ_AKT3) in the resistance of GC to cisplatin.Methods42 sensitive and 23 resistant GC patients were recruited for tissue collection. The cisplatin-resistant GC cells MKN-7/DDP and HGC-27/DDP were used for in vitro study. circ_AKT3, microRNA-206 (miR-206) and protein tyrosine phosphatase non-receptor type 14 (PTPN14) levels were detected via quantitative reverse transcription real-time PCR (qPCR) and Western blot. Cisplatin resistance was assessed by detecting P-glycoprotein (P-gp) level, half maximal inhibitory concentration (IC50) of cisplatin and cell apoptosis. The target relationship between miR-206 and circ_AKT3 or PTPN14 was analyzed via dual-luciferase reporter and RNA pull-down assays. The role of circ_AKT3 in vivo was assessed using xenograft model.Resultscirc_AKT3 level was increased, but miR-206 was declined in cisplatin-resistant GC tissues and cells. circ_AKT3 knockdown or miR-206 overexpression decreased the level of P-gp and IC50 of cisplatin and increased apoptosis of MKN-7/DDP and HGC-27/DDP cells. Additionally, circ_AKT3 targeted miR-206, and regulated cisplatin resistance by interacting with miR-206. PTPN14 was regulated by circ_AKT3 through miR-206 as a bridge. Also, circ_AKT3 knockdown decreased xenograft tumor growth.Conclusioncirc_AKT3 knockdown suppressed cisplatin resistance using miR-206/PTPN14 axis in cisplatin-resistant GC cells.

CircMMD_007 promotes oncogenic effects in the progression of lung adenocarcinoma through microRNA-197-3p/protein tyrosine phosphatase non-receptor type 9 axis

ABSTRACT Circular RNAs play important roles in cancer biology. In this research, we explored the underlying function and mechanism of cirMMD_007 in lung adenocarcinoma (LC). Clinical lung adenocarcinoma samples were obtained from surgery. Bioinformatic databases were used to predict miRNAs that can potentially target circRNAs and miRNA target genes. hsa_circMMD_007, miR-197-3p, and PTPN9 mRNA expressions were investigated by qRT-PCR. Protein expressions were examined using Western blot. The proliferation abilities were assessed by Cell Counting Kit-8 assays. Wound healing cell migration assay was applied to evaluate cell migration ability. Luciferase reporter assay and rescue experiments were then performed to elucidate the underlying mechanism. We found that the expression of circMMD_007 was abnormally increased in LC. The expression of circMMD_007 was higher in advanced stages. Knockout of circMMD_007 hindered the tumorigenesis of LC in vivo and in vitro. circMMD_007 could negatively regulate the expression of miR-197-3p. PTPN9 behaved to be a molecular target of miR-197-3p. In summary, this research demonstrated that circular RNA circMMD_007 could promote the oncogenic effects in the progression of LC through miR-197-3p/PTPN9 axis.

RMRP inhibition prevents NAFLD progression in rats via regulating miR-206/PTPN1 axis.

This study aimed to investigate the regulatory function of lncRNA RMRP in non-alcoholic fatty liver disease (NAFLD). In vitro and in vivo NAFLD models were constructed. Hematoxylin & Eosin (H&E) and Oil-Red O staining assays were conducted to observe the morphology and lipid accumulation in liver tissues. Triglycine (TG) secretion was detected by ELISA assay. The expression levels of RMRP, microRNA-206, PTPN1 (protein tyrosine phosphatase, non-receptor type 1), and their downstream genes were assessed by qRT-PCR and Western blot. The regulatory relationship among these molecules was determined by luciferase reporter and RNA pull-down assays. RMRP and PTPN1 were up-regulated, while miR-206 was down-regulated in the liver tissues of NAFLD patients and rat model. RMRP inhibition improved the pathological state and liver function-related indexes of liver lipid deposition in the liver tissues of NAFLD rats. RMRP inhibition alleviated steatosis and TG secretion in free fatty acids (FFA)-treated AML-12 cells. RMRP could bind to miR-206 and downregulate its expression. Meanwhile, RMRP inhibition attenuated lipid accumulation by downregulating the PTPN1-PP2ASP1-SREBP1C pathway. Furthermore, RMRP inhibited the miR-206/PTPN1-SREBP1C signaling pathway in NAFLD rats and FFA-treated AML-12 cells. RMRP inhibition prevented NAFLD progression in rats via targeting the miR-206/PTPN1 axis.

A role for the NPM1/PTPN14/YAP axis in mediating hypoxia-induced chemoresistance to sorafenib in hepatocellular carcinoma

BackgroundTumor microenvironments are characterized by resistance to chemotherapeutic agents and radiotherapy. Hypoxia plays an important role in the development of tumor resistance, as well as the generation of metastatic potential. YAP also participates in the regulation of hypoxia-mediated chemoresistance, and is negatively regulated by protein tyrosine phosphatase non-receptor type 14 (PTPN14).MethodsThe PTPN14 expression in hepatocellular carcinoma (HCC) tissues were evaluated by qRT-PCR, western blot and tissue microarrays. The effect of PTPN14 on HCC progression was investigated in vitro and in vivo.ResultsHere, we report that PTPN14 expression was downregulated in HCC tissues and cell lines. Silencing PTPN14 significantly enhanced proliferation, migration, invasion of HepG2 cells in vitro and tumor growth and metastasis in vivo, whereas overexpression of PTPN14 significantly inhibited these abilities in SK-Hep1 cells. We also found that hypoxia-induced nuclear translocation and accumulation of PTPN14 led to resistance to sorafenib in HCC cells. Further mechanistic studies suggested that NPM1 regulates PTPN14 localization, and that NPM1 regulates YAP by retaining PTPN14 in the nucleus under hypoxic conditions.ConclusionsThese data suggest that a therapeutic strategy against chemoresistant HCC may involve disruption of NPM1-mediated regulation of YAP by retaining PTPN14 in the nucleus under hypoxic conditions.

Syntenin-1-mediated small extracellular vesicles promotes cell growth, migration, and angiogenesis by increasing onco-miRNAs secretion in lung cancer cells

Small extracellular vesicles (sEVs) play a pivotal role in tumor progression by mediating intercellular communication in the tumor microenvironment (TME). Syntenin-1 induces malignant tumor progression in various types of human cancers, including human lung cancer and regulates biogenesis of sEVs. However, the function of syntenin-1-regulated sEVs and miRNAs in sEVs remains to be elucidated. In the present study, we aimed to demonstrate the role of oncogenic Ras/syntenin-1 axis in the release of sEVs and elucidate the function of syntenin-1-mediated miRNAs in sEVs in lung cancer progression. The results revealed that oncogenic Ras promoted the release of sEVs by inducing syntenin-1 expression; disruption of syntenin-1 expression impaired the release of sEVs as well as sEV-mediated cancer cell migration and angiogenesis. Moreover, we identified three miRNAs, namely miR-181a, miR-425-5p, and miR-494-3p, as onco-miRNAs loaded into syntenin-1-dependent sEVs. Remarkably, miR-494-3p was highly abundant in sEVs and its release was triggered by syntenin-1 expression and oncogenic Ras. Ectopic expression of the miR-494-3p mimic enhanced the migration and proliferation of lung cancer cells as well as tube formation in endothelial cells; however, the miR-494-3p inhibitor blocked sEV-mediated effects by targeting tyrosine-protein phosphatase nonreceptor type 12 (PTPN12), a tumor suppressor. sEVs promoted tumor growth and angiogenesis by downregulating PTPN12 expression; however, the miR-494-3p inhibitor significantly suppressed these effects in vivo, confirming that miR-494-3p acts as a major onco-miRNA loaded into lung cancer cell-derived sEVs. Eventually, the oncogenic Ras/syntenin-1 axis may induce cancer progression by increasing miR-494-3p loading into sEVs in lung cancer cells in the TME.

Structural and biochemical analysis of the PTPN4 PDZ domain bound to the C-terminal tail of the human papillomavirus E6 oncoprotein.

High-risk genotypes of human papillomaviruses (HPVs) are directly implicated in various abnormalities associated with cellular hyperproliferation, including cervical cancer. E6 is one of two oncoproteins encoded in the HPV genome, which recruits diverse PSD-95/Dlg/ZO-1 (PDZ) domain-containing human proteins through its C-terminal PDZ-binding motif (PBM) to be degraded by means of the proteasome pathway. Among the three PDZ domain-containing protein tyrosine phosphatases, protein tyrosine phosphatase non-receptor type 3 (PTPN3) and PTPN13 were identified to be recognized by HPV E6 in a PBM-dependent manner. However, whether HPV E6 associates with PTPN4, which also has a PDZ domain and functions as an apoptosis regulator, remains undetermined. Herein, we present structural and biochemical evidence demonstrating the direct interaction between the PBM of HPV16 E6 and the PDZ domain of human PTPN4 for the first time. X-ray crystallographic structure determination and binding measurements using isothermal titration calorimetry demonstrated that hydrophobic interactions in which Leu158 of HPV16 E6 plays a key role and a network of intermolecular hydrogen bonds sustain the complex formation between PTPN4 PDZ and the PBM of HPV16 E6. In addition, it was verified that the corresponding motifs from several other high-risk HPV genotypes, including HPV18, HPV31, HPV33, and HPV45, bind to PTPN4 PDZ with comparable affinities, suggesting that PTPN4 is a common target of various pathogenic HPV genotypes.