Tyrosine Phosphatase Activity Research Articles

Cancer-associated point mutations within the extracellular domain of PTPRD affect protein stability and HSPG interaction.

PTPRD, a well-established tumor suppressor gene, encodes the protein tyrosine phosphatase-type D. This protein consists of three immunoglobulin-like (Ig) domains, four to eight fibronectin type 3 (FN) domains, a single transmembrane segment, and two cytoplasmic tandem tyrosine phosphatase domains. PTPRD is known to harbor various cancer-associated point mutations. While it is assumed that PTPRD regulates cellular functions as a tumor suppressor through the tyrosine phosphatase activity in the intracellular region, the function of its extracellular domain (ECD) in cancer is not well understood. In this study, we systematically examined the impact of 92 cancer-associated point mutations within the ECD. We found that 69.6% (64 out of 92) of these mutations suppressed total protein expression and/or plasma membrane localization. Notably, almost all mutations (20 out of 21) within the region between the last FN domain and transmembrane segment affected protein expression and/or localization, highlighting the importance of this region for protein stability. We further found that some mutations within the Ig domains adjacent to the glycosaminoglycan-binding pocket enhanced PTPRD's binding ability to heparan sulfate proteoglycans (HSPGs). This interaction is proposed to suppress phosphatase activity. Our findings therefore suggest that HSPG-mediated attenuation of phosphatase activity may be involved in tumorigenic processes through PTPRD dysregulation.

Citric Acid Controls the Activity of YopH Bacterial Tyrosine Phosphatase.

Citric acid (CA) is a tricarboxylic acid with antioxidant and antimicrobial properties. Based on previous studies, the small compound with its three carboxylic groups can be considered a protein tyrosine phosphatase inhibitor. YopH, a protein tyrosine phosphatase, is an essential virulence factor in Yersinia bacteria. We performed enzymatic activity assays of YopH phosphatase after treatment with citric acid in comparison with the inhibitory compound trimesic acid, which has a similar structure. We also measured the cytotoxicity of these compounds in Jurkat T E6.1 and macrophage J774.2 cell lines. We performed molecular docking analysis of the binding of citric acid molecules to YopH phosphatase. Citric acid and trimesic acid reversibly reduced the activity of YopH enzyme and decreased the viability of Jurkat and macrophage cell lines. Importantly, these two compounds showed greater inhibitory properties against bacterial YopH activity than against human CD45 phosphatase activity. Molecular docking simulations confirmed that citric acid could bind to YopH phosphatase. Citric acid, a known antioxidant, can be considered an inhibitor of bacterial phosphatases.

Current Understanding of Androgen Signaling in Prostatitis and its Treatment: A Review.

Chronic prostatitis is a highly prevalent condition that significantly impacts the quality of life and fertility of men. Because of its heterogeneous nature, there is no definitive treatment, which requires ongoing research into its etiology. Additionally, the association between prostatitis and an elevated risk of prostate cancer highlights the importance of comprehending androgen involvement in prostatitis. This paper examines the current understanding of androgen signaling in prostatitis and explores contemporary therapeutic approaches. We reviewed Medline articles comprehensively, using keywords such as nonbacterial prostatitis, prostatitis infertility, androgen role in prostatitis, and chronic pelvic pain. Several cellular targets are linked to androgen signaling. Notably, the major tyrosine phosphatase activity (cPAcP) in normal human prostate is influenced by androgen signaling, and its serum levels inversely correlate with prostate cancer progression. Androgens also regulate membrane-associated zinc and pyruvate transporters transduction in prostate cells, suggesting promising avenues for novel drug development aimed at inhibiting these molecules to reduce cancer tumor growth. Various therapies for prostatitis have been evaluated, including antibiotics, anti-inflammatory medications (including bioflavonoids), neuromodulators, alpha-blockers, 5α-reductase inhibitors, and androgen receptor antagonists. These therapies have demonstrated varying degrees of success in ameliorating symptoms. In conclusion, aging decreases circulating T and intraprostatic DHT, altering the proper functioning of the prostate, reducing the ability of androgens to maintain normal Zn2+ levels, and diminishing the secretion of citrate, PAcP, and other proteins into the prostatic fluid. The Zn2+-transporter decreases or is absent in prostate cancer, so the pyruvate transporter activates. Consequently, the cell ATP increases, inducing tumor growth.

Preparation of Oxidized and Reduced PTP4A1 for Structural and Functional Studies.

The formation of a reversible disulfide bond between the catalytic cysteine and a spatially neighboring cysteine (backdoor) in protein tyrosine phosphatases (PTPs) serves as a critical regulatory mechanism for maintaining the activity of protein tyrosine phosphatases. The failure of such protection results in the formation of irreversibly oxidized cysteines into sulfonic acid in a highly oxidative cellular environment in the presence of free radicals. Hence, it is important to develop methods to interconvert PTPs into reduced and oxidized forms to understand their catalytic function in vitro. Protein tyrosine phosphatase 4A type 1 (PTP4A1), a dual-specificity phosphatase, is catalytically active in the reduced form. Unexpectedly, also its oxidized form performs a key biological function in systemic sclerosis (SSc) by forming a kinase-phosphatase complex with Src kinases. Thus, we developed simple and efficient protocols for producing oxidized and reduced PTP4A1 to elucidate their biological function, which can be extended to study other protein tyrosine phosphatases and other recombinantly produced proteins.

The Tyrosine Phosphatase Activity of PTPN22 Is Involved in T Cell Development via the Regulation of TCR Expression.

The protein tyrosine phosphatase PTPN22 inhibits T cell activation by dephosphorylating some essential proteins in the T cell receptor (TCR)-mediated signaling pathway, such as the lymphocyte-specific protein tyrosine kinase (Lck), Src family tyrosine kinases Fyn, and the phosphorylation levels of Zeta-chain-associated protein kinase-70 (ZAP70). For the first time, we have successfully produced PTPN22 CS transgenic mice in which the tyrosine phosphatase activity of PTPN22 is suppressed. Notably, the number of thymocytes in the PTPN22 CS mice was significantly reduced, and the expression of cytokines in the spleen and lymph nodes was changed significantly. Furthermore, PTPN22 CS facilitated the positive and negative selection of developing thymocytes, increased the expression of the TCRαβ-CD3 complex on the thymus cell surface, and regulated their internalization and recycling. ZAP70, Lck, Phospholipase C gamma1(PLCγ1), and other proteins were observed to be reduced in PTPN22 CS mouse thymocytes. In summary, PTPN22 regulates TCR internalization and recycling via the modulation of the TCR signaling pathway and affects TCR expression on the T cell surface to regulate negative and positive selection. PTPN22 affected the development of the thymus, spleen, lymph nodes, and other peripheral immune organs in mice. Our study demonstrated that PTPN22 plays a crucial role in T cell development and provides a theoretical basis for immune system construction.

Network pharmacology and experiment indicated that medicinal food homologous components play important roles in insomnia

AbstractInsomnia refers to a subjective experience where insufficient sleep duration and quality affect daytime social functioning. This study aims to screen bioactive components with medicinal food homologous (MFH), such as quercetin, beta‐sitosterol, kaempferol, stigmasterol, and capsaicin, which can treat insomnia and demonstrate that quercetin acts as a direct inhibitor of insomnia‐related glucosylceramidase and as an insulin receptor tyrosine phosphatase inhibitor in the upstream insulin signaling pathway, affecting insomnia targets in the downstream pathway for the treatment of insomnia, using network pharmacology and cell experiment approaches. The results showed that 703 components in 44 MFH were enriched in 139 metabolic pathways and acted on 210 potential targets of insomnia. The protein–protein interaction network is analyzed by cytoNCA, according to the topological analysis results, quercetin, beta‐sitosterol, kaempferol, stigmasterol, and capsaicin of betweenness ranked in the top 10. Quercetin and glucosylceramidase were shown to directly inhibit insomnia proteins through reverse molecular docking. Quercetin was used to culture and stimulate HepG2 cells to detect tyrosine phosphorylation of key cellular proteins in the insulin signaling pathway, concluding that quercetin inhibits the activity of tyrosine phosphatase in a dose‐dependent manner, activating the insulin signaling pathway, triggering a cascade reaction, and affecting the expression of insomnia targets in the downstream pathway. The molecular docking of tyrosine phosphatase and quercetin revealed that quercetin interacted with it near the catalytic site, thereby inhibiting its interaction with the substrate. Overall, this study facilitates the development of medicinal food homologous, which exerts good pharmacological effects in the treatment of insomnia.

Promoting the activity of a receptor tyrosine phosphatase with a novel pH-responsive transmembrane agonist inhibits cancer-associated phenotypes.

Cell signaling by receptor protein tyrosine kinases (RTKs) is tightly controlled by the counterbalancing actions of receptor protein tyrosine phosphatases (RPTPs). Due to their role in attenuating the signal-initiating potency of RTKs, RPTPs have long been viewed as therapeutic targets. However, the development of activators of RPTPs has remained limited. We previously reported that the homodimerization of a representative member of the RPTP family (protein tyrosine phosphatase receptor J or PTPRJ) is regulated by specific transmembrane (TM) residues. Disrupting this interaction by single point mutations promotes PTPRJ access to its RTK substrates (e.g., EGFR and FLT3), reduces RTK's phosphorylation and downstream signaling, and ultimately antagonizes RTK-driven cell phenotypes. Here, we designed and tested a series of first-in-class pH-responsive TM peptide agonists of PTPRJ that are soluble in aqueous solution but insert as a helical TM domain in lipid membranes when the pH is lowered to match that of the acidic microenvironment of tumors. The most promising peptide reduced EGFR's phosphorylation and inhibited cancer cell EGFR-driven migration and proliferation, similar to the PTPRJ's TM point mutations. Developing tumor-selective and TM-targeting peptide binders of critical RPTPs could afford a potentially transformative approach to studying RPTP's selectivity mechanism without requiring less specific inhibitors and represent a novel class of therapeutics against RTK-driven cancers.

EYA2 tyrosine phosphatase inhibition reduces MYC and prevents medulloblastoma progression.

Medulloblastoma is the most common pediatric brain malignancy. Patients with the Group 3 subtype of medulloblastoma (MB) often exhibit MYC amplification and/or overexpression and have the poorest prognosis. While Group 3 MB is known to be highly dependent on MYC, direct targeting of MYC remains elusive. Patient gene expression data were used to identify highly expressed EYA2 in Group 3 MB samples, assess the correlation between EYA2 and MYC, and examine patient survival. Genetic and pharmacological studies were performed on EYA2 in Group 3 derived MB cell models to assess MYC regulation and viability in vitro and in vivo. EYA2 is more highly expressed in Group 3 MB than other MB subgroups and is essential for Group 3 MB growth in vitro and in vivo. EYA2 regulates MYC expression and protein stability in Group 3 MB, resulting in global alterations of MYC transcription. Inhibition of EYA2 tyrosine phosphatase activity, using a novel small molecule inhibitor (NCGC00249987, or 9987), significantly decreases Group 3 MB MYC expression in both flank and intracranial growth in vivo. Human MB RNA-seq data show that EYA2 and MYC are significantly positively correlated, high EYA2 expression is significantly associated with a MYC transcriptional signature, and patients with high EYA2 and MYC expression have worse prognoses than those that do not express both genes at high levels. Our data demonstrate that EYA2 is a critical regulator of MYC in Group 3 MB and suggest a novel therapeutic avenue to target this highly lethal disease.

Neonatal malnutrition impacts fibroblast growth factor 21-induced neuron neurite outgrowth and growth hormone-releasing hormone secretion in neonatal mouse brain

Neonatal malnutrition is one of the most common causes of neurological disorders. However, the mechanism of action of the factors associated with neonatal nutrition in the brain remains unclear. In this study, we focused on fibroblast growth factor (FGF) 21 to elucidate the effects of malnutrition on the neonatal brain. FGF21 is an endocrine factor produced by the liver during lactation which is the main source of nutrition during the neonatal period. In this study, malnourishment during nursing mice induced decreased levels of Fgf21 mRNA in the liver and decreased levels of FGF21 in the serum. RNA-seq analysis of neonatal mouse brain tissue revealed that FGF21 controlled the expression of Kalrn-201 in the neonatal mouse brain. Kalrn-201 is a transcript of Kalirin, a Ras homologous guanine nucleotide exchange factor at the synapse. In mouse neurons, FGF21 induced the expression of Kalirin-7 (a Kalirin isoform) by down-regulating Kalrn-201. FGF21-induced Kalirin-7 stimulated neurite outgrowth in Neuro-2a cells. FGF21 also induced Growth hormone-releasing hormone (GHRH) expression in Neuro-2a cells. Kalirin-7 and GHRH expression induced by FGF21 was altered by inhibiting the activity of SH2-containing tyrosine phosphatase (SHP2) which is located downstream of the FGF receptor (FGFR). Additionally, malnourished nursing induced intron retention of the SHP2 gene (Ptpn11), resulting in the alteration of Kalirin-7 and GHRH expression by FGF21 signaling. Ptpn11 intron retention is suggested to be involved in regulating SHP2 activity. Taken together, these results suggest that FGF21 plays a critical role in the induction of neuronal neurite outgrowth and GHRH secretion in the neonatal brain, and this mechanism is regulated by SHP2. Thus, Ptpn11 intron retention induced by malnourished nursing may be involved in SHP2 activity.

Alteration of circulating ACE2-network related miRNAs in patients with COVID-19

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Medical University of Warsaw and São Paulo Research Foundation (FAPESP). Introduction Coronavirus disease 2019 (COVID-19) is associated with an increased risk of mortality and adverse cardiovascular (CV) occurrences, especially in a group of patients with CV diseases (CVD). SARS-CoV-2 virus enters cells through angiotensin converting enzyme 2 (ACE2) cell membrane enzymes, leading to the downregulation in the ACE2-related pathways. Based on our previous in silico [1] results we hypothesized that alteration in the ACE2 interaction network caused by virus infection can affect the expression of miRNAs and influence severity of the disease. Purpose In this study we aimed to analyse the diagnostic and predictive utility of ACE2-related miRNAs, which were identified in our previous in silico analysis (miR-10b-5p, miR-124-3p, miR-200b-3p, miR-26b-5p, miR-302c-5p) in patients with COVID-19. We also aimed to unravel the functions of analyzed miRNAs, by using machine learning based tools, including SHAP for clinical data analysis, and bioinformatic tools for data mining, target predictions and enrichment analyses. Methods Blood samples and clinical data of 79 COVID-19 patients were collected at three different time points, including the day of admission, 7-days and 21-days after admission, as well as one time-point of 32 healthy volunteers. The composite endpoint was hospitalisation length of stay (>21 days) and/or death in follow-up. Results Delta low miR-200b-3p expression (after 7-days of admission) presents predictive utility in assessment of the hospital length of stay and/or death in ROC curve analysis (AUC:0.730, p=0.002) (Fig. 1). Delta low miR-200b-3p expression, together with diabetes mellitus (DM) are independent predictors of increased hospital length of stay and/or death (OR= 5.775; CI= 1.572- 21.214; p= 0.008, OR= 4.888; CI= 1.001- 23.858; p= 0.050, respectively). The expression levels of miR-26b-5p and miR-10b-5p in COVID-19 patients were found lower at the baseline, 7 and 21-days after admission compared to the healthy controls (p<0.0001 for all time points). SHAP analysis indicated levels of miR 200b-3p (day 7th), miR-302c-5p (day 7th), CRP (day 7th), neutrophils (day 0), and D-Dimer (day 0) as the most promising predictors of long hospitalisation for the COVID-19 patients. Pathway enrichment analysis showed that among top shared pathways between targets of analyzed miRNAs were IL-2 signaling pathway, and Pathways in cancer. miR-200b-3p showed regulation of COVID-19-related targets associated with T cell protein tyrosine phosphatase and HIF-1 transcriptional activity in hypoxia, key pathways in COVID-19. Bioinformatics analysis pointed out the role of those miRNAs in multiple CVD phenotypes associated with COVID-19 (Fig. 2). Conclusions In this study we validated and characterized miRNAs which could serve as novel, predictive biomarkers of the COVID-19 long term hospitalisation and can be used for early stratification of patients and prediction of severity of infection development in an individual.

TULA Proteins in Men, Mice, Hens, and Lice: Welcome to the Family.

The two members of the UBASH3/STS/TULA protein family have been shown to critically regulate key biological functions, including immunity and hemostasis, in mammalian biological systems. Negative regulation of signaling through immune receptor tyrosine-based activation motif (ITAM)- and hemITAM-bearing receptors mediated by Syk-family protein tyrosine kinases appears to be a major molecular mechanism of the down-regulatory effect of TULA-family proteins, which possess protein tyrosine phosphatase (PTP) activity. However, these proteins are likely to carry out some PTP-independent functions as well. Whereas the effects of TULA-family proteins overlap, their characteristics and their individual contributions to cellular regulation also demonstrate clearly distinct features. Protein structure, enzymatic activity, molecular mechanisms of regulation, and biological functions of TULA-family proteins are discussed in this review. In particular, the usefulness of the comparative analysis of TULA proteins in various metazoan taxa, for identifying potential roles of TULA-family proteins outside of their functions already established in mammalian systems, is examined.

The Sts Proteins: Modulators of Host Immunity.

The suppressor of TCR signaling (Sts) proteins, Sts-1 and Sts-2, are a pair of closely related signaling molecules that belong to the histidine phosphatase (HP) family of enzymes by virtue of an evolutionarily conserved C-terminal phosphatase domain. HPs derive their name from a conserved histidine that is important for catalytic activity and the current evidence indicates that the Sts HP domain plays a critical functional role. Sts-1HP has been shown to possess a readily measurable protein tyrosine phosphatase activity that regulates a number of important tyrosine-kinase-mediated signaling pathways. The in vitro catalytic activity of Sts-2HP is significantly lower than that of Sts-1HP, and its signaling role is less characterized. The highly conserved unique structure of the Sts proteins, in which additional domains, including one that exhibits a novel phosphodiesterase activity, are juxtaposed together with the phosphatase domain, suggesting that Sts-1 and -2 occupy a specialized intracellular signaling niche. To date, the analysis of Sts function has centered predominately around the role of Sts-1 and -2 in regulating host immunity and other responses associated with cells of hematopoietic origin. This includes their negative regulatory role in T cells, platelets, mast cells and other cell types, as well as their less defined roles in regulating host responses to microbial infection. Regarding the latter, the use of a mouse model lacking Sts expression has been used to demonstrate that Sts contributes non-redundantly to the regulation of host immunity toward a fungal pathogen (C. albicans) and a Gram-negative bacterial pathogen (F. tularensis). In particular, Sts-/- animals demonstrate significant resistance to lethal infections of both pathogens, a phenotype that is correlated with some heightened anti-microbial responses of phagocytes derived from mutant mice. Altogether, the past several years have seen steady progress in our understanding of Sts biology.

Abstract 625: Alteration Of Circulating Ace2-network Related Micrornas In Patients With Covid-19

ACE2 interaction network caused by virus infection can affect the expression levels of miRNAs and influence severity of COVID19. This study aimed to analyse the diagnostic/predictive utility of ACE2-related miRNAs, identified by in silico analysis: miR10b, miR124, miR200b-3p, miR26b, miR302c-5p in patients with COVID-19, and aimed to unravel the functions of miRNAs, by using machine learning-SHAP analysis for clinical data and bioinformatic tools. Blood samples and clinical data of 79 patients and 32 healthy were collected at; day of admission, 7days and 21days after admission. Endpoint was hospitalisation length of stay (>21days) and/or death in follow-up. Delta low miR200b-3p expression (7days-admission) presents predictive utility in assessment of the hospital length of stay and/or death (AUC:0.73,p=0.002). Logistic regression analysis showed that delta low miR-200b-3p, diabetes are independent predictors of increased hospital length of stay and/or death (OR=5.8;CI=0.57-21.21;p= 0.008, OR= 4.9;CI=1-23.9;p=0.04). MiR-26b-5p and miR10b in patients were found lower at the baseline, 7 and 21days after admission compared to healthy controls (p<0.0001 for all time points). SHAP analysis showed miR200b-3p (day7), miR302c-5p (day7), CRP (day7), neutrophils (day0), and DDimer (day0) as most promising predictors of long hospitalisation. Pathway-enrichment showed the following top pathways of the interleukin-2 signaling pathway, and cancer pathways. MiR200b-3p showed regulation of COVID19-related targets associated with Tcell protein tyrosine phosphatase and HIF-1 transcriptional activity in hypoxia, key pathways in COVID19. Bioinformatics analysis showed miRNAs roles in multiple CVDs phenotypes associated with COVID19. We validated/characterized miRNAs which can serve as novel, predictive biomarkers of the long term COVID19 hospitalisation and can be used for early stratification of patients and prediction of severity of infection.

Protein Tyrosine Phosphatase Receptor Zeta 1 as a Potential Target in Cancer Therapy and Diagnosis.

Protein tyrosine phosphatase receptor zeta 1 (PTPRZ1) is a type V transmembrane tyrosine phosphatase that is highly expressed during embryonic development, while its expression during adulthood is limited. PTPRZ1 is highly detected in the central nervous system, affecting oligodendrocytes' survival and maturation. In gliomas, PTPRZ1 expression is significantly upregulated and is being studied as a potential cancer driver and as a target for therapy. PTPRZ1 expression is also increased in other cancer types, but there are no data on the potential functional significance of this finding. On the other hand, low PTPRZ1 expression seems to be related to a worse prognosis in some cancer types, suggesting that in some cases, it may act as a tumor-suppressor gene. These discrepancies may be due to our limited understanding of PTPRZ1 signaling and tumor microenvironments. In this review, we present evidence on the role of PTPRZ1 in angiogenesis and cancer and discuss the phenomenal differences among the different types of cancer, depending on the regulation of its tyrosine phosphatase activity or ligand binding. Clarifying the involved signaling pathways will lead to its efficient exploitation as a novel therapeutic target or as a biomarker, and the development of proper therapeutic approaches.

Application of hybrid biophysical-biochemical methods to unravel the molecular basis for auto-inhibition and activation of protein tyrosine phosphatase TCPTP/PTPN2.

Since the discovery of protein tyrosine phosphorylation as one of the critical post-translational modifications, it has been well known that the activity of protein tyrosine kinases (PTKs) is tightly regulated. On the other hand, protein tyrosine phosphatases (PTPs) are often regarded to act constitutively active, but recently we and others have shown that many PTPs are expressed in an inactive form due to allosteric inhibition by their unique structural features. Furthermore, their cellular activity is highly regulated in a spatiotemporal manner. In general, PTPs share a conserved catalytic domain comprising about 280 residues that is flanked by either an N-terminal or a C-terminal non-catalytic segment, which differs significantly in size and structure from each other and is known to regulate specific PTP's catalytic activity. The well-characterized non-catalytic segments can be globular or intrinsically disordered. In this work, we have focused on the T-Cell Protein Tyrosine Phosphatase (TCPTP/PTPN2) and demonstrated how the hybrid biophysical-biochemical methods can be applied to unravel the underlying mechanism through which TCPTP's catalytic activity is regulated by the non-catalytic C-terminal segment. Our analysis showed that TCPTP is auto-inhibited by its intrinsically disordered tail and trans-activated by Integrin alpha-1's cytosolic region.

Lead suppresses perlecan expression via EGFR-ERK1/2-COX-2-PGI2 pathway in cultured bovine vascular endothelial cells.

Vascular endothelial cell growth is essential for the repair of intimal injury. Perlecan, a large heparan sulfate proteoglycan, intensifies fibroblast growth factor-2 (FGF-2) signaling as a co-receptor for FGF-2 and its receptor, and promotes the proliferation of vascular endothelial cells. Previously, we reported that 2 µM of lead, a toxic heavy metal, downregulated perlecan core protein expression and then suppressed the growth of vascular endothelial cells. However, since the mechanisms involved in the repression of perlecan by lead remains unclear, we analyzed its detailed signaling pathway using cultured bovine aortic endothelial cells. Our findings indicate that 2 µM of lead inhibited protein tyrosine phosphatase (PTP) activity and induced cyclooxygenase-2 (COX-2) via phosphorylation of the epidermal growth factor receptor (EGFR) and its downstream extracellular signal-regulated kinases (ERK1/2). In addition, among the prostanoids regulated by COX-2, prostaglandin I2 (PGI2) specifically contributes to the downregulation of perlecan expression by lead. This study revealed an intracellular pathway-the EGFR-ERK1/2-COX-2-PGI2 pathway activated by inhibition of PTP by lead-as a pathway that downregulates endothelial perlecan synthesis. The pathway is suggested to serve as a mechanism for the repression of perlecan expression, which leads to a delay in cell proliferation by lead.

Site-Selective Tyrosine Phosphorylation in the Activation of the p50 Subunit of NF-κB for DNA Binding and Transcription.

The family of NF-κB transcriptional activators controls the expression of many genes, including those involved in cell survival and development. The family consists of homo- and heterodimers constituted by combinations of five subunits. Subunit p50 includes 13 tyrosine residues, but the relationship between specific tyrosine phosphorylations and p50 function is not well understood. Subunits of p50 and p65 prepared in vitro formed a heterodimer, but this NF-κB would not bind to the interleukin-2 (IL-2) promoter DNA. Treatment of p50 with guanosine triphosphate (GTP) and a lysate from activated Jurkat cells, effected rapid p50 phosphorylation, and, in the presence of wild-type subunit p65, was accompanied on the same time scale by IL-2 promoter DNA binding. Modified p50s containing one of seven stoichiometrically phosphorylated tyrosines in NF-κB p50/p65 heterodimers, included three that facilitated binding to the IL-2 DNA promoter region to a greater extent than the wild type. One of these three stoichiometrically phosphorylated p50/p65 heterodimers of NF-κB, containing pTyr60 in the p50 subunit, was treated with a lysate from activated Jurkat cells + GTP and shown to be phosphorylated on the same time scale as wild-type p50. This modified NF-κB also developed IL-2 promoter DNA binding activity on the same time scale as the wild type but exhibited greater binding to the IL-2 DNA promoters than the wild type. The nature of this enhanced binding was studied in greater detail using a metabolically stable pTyr derivative at position 60 of p50 and cellular phosphatases. We suggest that enhanced DNA binding of modified NF-κB containing pTyr60 in the p50 subunit may reflect stoichiometric NF-κB phosphorylation at a site that is not normally fully phosphorylated, or not phosphorylated at all, and is relatively resistant to the effects of Jurkat cell tyrosine phosphatase activity. This conclusion was reinforced by demonstrating that modification of Tyr60 of p50 with a metabolically stable methylenephosphonate moiety further increased the stability of the formed NF-κB p50/p65 heterodimer against the action of activated Jurkat cell phosphatases.

Targeted OUM1/PTPRZ1 silencing and synergetic CDT/enhanced chemical therapy toward uveal melanoma based on a dual-modal imaging-guided manganese metal–organic framework nanoparticles

Metastasis and chemical resistance are the most serious problems in the treatment of highly aggressive uveal melanoma (UM). The newly identified lncRNA OUM1 is overexpressed in UM, functions as a catalyst and regulates protein tyrosine phosphatase (PTP) activity by binding to PTP receptor type Z1 (PTPRZ1), which plays an important role in cell proliferation, metastasis and chemotherapy resistance in the UM microenvironment. Hence, siRNAs that selectively knocking down the lncRNA OUM1 (siOUM1) and its target gene PTPRZ1 (siPTPRZ1) were designed to inhibit the OUM1/PTPRZ1 pathway to reduce PTP activity, and this reduction in activity interrupts protein tyrosine phosphorylation, suppresses UM proliferation and metastasis and improves cisplatin sensitivity in UM cells. Then, to overcome the limitations of the difficulty of drug administration and traditional therapeutics, the indocyanine green (ICG)-labeled manganese metal–organic framework (MOF) nanoparticles (NPs) were fabricated and linked with arginine-glycine-aspartate (RGD) peptide to carry siOUM1/siPTPRZ1 and cisplatin to achieve targeted siRNA interference-mediated therapy, enhanced cisplatin therapy and chemodynamic therapy. This NP system also has a dual-modal imaging ability because ICG is a near-infrared region fluorescent dye and manganese has the potential to be used in magnetic resonance imaging. This study verifies the significance of the newly discovered lncRNA OUM1 as a new therapeutic target for aggressive UM and provides a drug delivery NP system for precise treatment of UM accompanied with a dual-modal imaging ability.Graphical

Enhanced IFN Sensing by Aggressive Chronic Lymphocytic Leukemia Cells.

Type I IFN is made by cells in response to stress. Cancer cells exist in a state of stress, but their IFN response is complex and not completely understood. This study investigated the role of autocrine IFN in human chronic lymphocytic leukemia (CLL) cells. CLL cells were found to make low amounts of IFN via TANK-binding kinase 1 pathways, but p-STAT1 and -STAT2 proteins along with IFN-stimulated genes that reflect IFN activation were variably downregulated in cultured CLL cells by the neutralizing IFNAR1 Ab anifrolumab. Patients with CLL were segregated into two groups based on the response of their leukemia cells to anifrolumab. Samples associated with more aggressive clinical behavior indicated by unmutated IGHV genes along with high CD38 and p-Bruton's tyrosine kinase expression exhibited responses to low amounts of IFN that were blocked by anifrolumab. Samples with more indolent behavior were unaffected by anifrolumab. Hypersensitivity to IFN was associated with higher expression of IFNAR1, MX1, STAT1, and STAT2 proteins and lower activity of negative regulatory tyrosine phosphatases. Autocrine IFN protected responsive CLL cells from stressful tissue culture environments and therapeutic drugs such as ibrutinib and venetoclax in vitro, in part by upregulating Mcl-1 expression. These findings suggest hypersensitivity to IFN may promote aggressive clinical behavior. Specific blockade of IFN signaling may improve outcomes for patients with CLL with higher-risk disease.

Activation of SH2 domain-containing protein tyrosine phosphatase and inflammatory expression in psoriasis

Psoriasis is a chronic autoimmune disease characterized by abnormal proliferation and differentiation of keratinocytes and infiltration of inflammatory cells into the site of inflammation. Plaque psoriasis is the most common type of psoriasis, affecting up to 80–90% of psoriasis cases. Among inflammatory cells, myeloid dendritic cells or Langerhans cells are mainly activated cells during the pathogenesis of psoriasis to induce activation and differentiation of naive T cells into T helper cells (Th)1 and Th17 cells. SH2 domain-containing protein tyrosine phosphatase (SHP) is a negative regulator of the phosphorylation of several proteins involved in cellular differentiation, growth and activation. Chronic inflammation promotes tumor progression, which is characterized by the release of carcinogenic antigens, including alpha-fetoprotein (AFP) and cancer antigen 125 (CA125) into blood and urine. They are common tumor markers to serve as predictors of cancer development and survival of cancer patients. To this end, blood samples of 103 psoriasis patients and 46 healthy subjects were collected. The mRNA expressions of SHP1 and SHP2 were examined by using quantitative RT-PCR and the serum levels of IL-6, TNF-α, IFN-γ, IL-17A, AFP and CA125 by ELISA. As a result, the mRNA level of SHP1 was higher expressed, whereas the level of SHP2 was unaltered in the patient group compared to the control individuals. Importantly, psoriasis patients had CA125 level higher than the clinical cutoff 35U/mL was 15.6%, while healthy individuals had CA125 level lower than 35U/mL. In addition, the serum TNF-α and IL-17A concentrations were significantly increased in the patient group. In conclusion, the results indicated the significant differences in expression of SHP1 gene and inflammatory response in psoriasis patients. This study further hint for investigations on the functional role of SHP1 in regulating activation of immune cells present in psoriasis patients.