Development of Novel Phosphonodifluoromethyl-Containing Phosphotyrosine Mimetics and a First-In-Class, Potent, Selective, and Bioavailable Inhibitor of Human CDC14 Phosphatases.

Together with protein tyrosine kinases, protein tyrosine phosphatases (PTPs) control protein tyrosine phosphorylation and regulate numerous cellular functions. Dysregulated PTP activity is associated with the onset of multiple human diseases. Nevertheless, understanding of the physiological function and disease biology of most PTPs remains limited, largely due to the lack of PTP-specific chemical probes. In this study, starting from a well-known nonhydrolyzable phosphotyrosine (pTyr) mimetic, phosphonodifluoromethyl phenylalanine (F2Pmp), we synthesized 7 novel phosphonodifluoromethyl-containing bicyclic/tricyclic aryl derivatives with improved cell permeability and potency toward various PTPs. Furthermore, with fragment- and structure-based design strategies, we advanced compound 9 to compound 15, a first-in-class, potent, selective, and bioavailable inhibitor of human CDC14A and B phosphatases. This study demonstrates the applicability of the fragment-based design strategy in creating potent, selective, and bioavailable PTP inhibitors and provides a valuable probe for interrogating the biological roles of hCDC14 phosphatases and assessing their potential for therapeutic interventions.

Semaglutide ameliorates pressure overload-induced cardiac hypertrophy by improving cardiac mitophagy to suppress the activation of NLRP3 inflammasome.

Pathological cardiac hypertrophy is an important cause of heart failure(HF). Recent studies reveal that glucagon-like peptide-1 receptor (GLP1R) agonists can improve mortality and left ventricular ejection fraction in the patients with type 2 diabetes and HF. The present study aims to investigate whether semaglutide, a long-acting GLP1R agonist, can ameliorate cardiac hypertrophy induced by pressure overload, and explore the potential mechanism. The rats were performed transverse aortic constriction (TAC) to mimic pressure overload model. The rats were divided into four groups including Sham, TAC, TAC + semaglutide, and TAC + semaglutide + HCQ (hydroxychloroquine, an inhibitor of mitophagy). The rats in each experimental group received their respective interventions for 4 weeks. The parameters of left ventricular hypertrophy(LVH) were measured by echocardiography, Hematoxylin-eosin (HE) staining, western-blot and immunohistochemistry (IHC), respectively. The changes of mitophagy were reflected by detecting cytochrome c oxidase subunit II (COXII), LC3II/LC3I, mitochondria, and autophagosomes. Meanwhile, NLRP3, Caspase-1, and interleukin-18 were detected to evaluate the activation of NLRP3 inflammasome in each group. The results suggest that LVH, impaired mitophagy, and activation of NLRP3 inflammasome were present in TAC rats. Semaglutide significantly reduced LVH, improve mitophagy, and down-regulated NLRP3 inflammatory signal pathway in TAC rats. However, the reversed effect of semaglutide on cardiac hypertrophy was abolished by HCQ, which restored the activation of NLRP3 inflammasome suppressed by improved mitophagy. In conclusion, semaglutide ameliorates the cardiac hypertrophy by improving cardiac mitophagy to suppress the activation of NLRP3 inflammasome. Semaglutide may be a novel potential option for intervention of cardiac hypertrophy induced by pressure overload.

Natural Product-Inspired Molecules for Covalent Inhibition of SHP2 Tyrosine Phosphatase.

Natural products have been playing indispensable roles in the development of lifesaving drug molecules. They are also valuable sources for covalent protein modifiers. However, they often are scarce in nature and have complex chemical structures, which are limiting their further biomedical development. Thus, natural product-inspired small molecules which still contain the essence of the parent natural products but are readily available and amenable for structural modification, are important and desirable in searching for lead compounds for various disease treatment. Inspired by the complex and diverse ent-kaurene diterpenoids with significant biological activities, we have created a synthetically accessible and focused covalent library by incorporating the bicyclo[3.2.1]octane α-methylene ketone, which is considered as the pharmacophore of ent-kaurene diterpenoids, as half of the structure, and replacing the other half with much less complex but more druglike scaffolds. From this library, we have identified and characterized selective covalent inhibitors of protein tyrosine phosphatase SHP2, an important anti-cancer therapeutic target. The success of this study demonstrated the importance of creating and evaluating natural product-inspired library as well as their application in targeting challenging disease targets.

Efficacy of catheter ablation for atrial fibrillation in heart failure: a meta-analysis of randomized controlled trials.

The study aims to evaluate whether rhythm control by catheter ablation is superior to medical therapy for the patients with atrial fibrillation (AF) and heart failure (HF). The literatures were searched by using PubMed, Cochrane Library, Embase, and Web of Science databases up to 12 October 2023. The randomized controlled trials (RCTs) comparing rhythm control using catheter ablation vs. medical therapy in AF patients with HF were pooled. The primary outcomes included all-cause mortality, HF re-hospitalization, and stroke, and the secondary outcomes included left ventricular ejection fraction (LVEF), atrial tachyarrythmia recurrence, quality of life (Minnesota Living with Heart Failure Questionnaire score, MLHFQ score), 6 min walking distance (6MWD), the level of N-terminal B-type natriuretic peptide precursor (NT-proBNP), and adverse events. Nine RCTs involving in 2293 patients met the inclusion criteria. Compared with medical therapy, catheter ablation reduced all-cause mortality [10.07% (121/1201) vs. 15.26% (175/1147), risk ratio (RR):0.60, 95% confidence interval (CI): 0.48-0.74, P < 0.00001, I2 = 0%] and the rate of HF re-hospitalization (RR: 0.65, P = 0.02, 95% CI: 0.45 to 0.94, I2 = 74%), but had no obvious difference in incidence of stroke (RR: 0.67, P = 0.27, 95% CI: 0.32 to 1.38, I2 = 0%). Catheter ablation enhanced LVEF [mean difference (MD), 6.26%, P < 0.00001, I2 = 89%], reduced AT recurrence (RR: 0.37, P < 0.00001, 95% CI: 0.26 to 0.52, I2 = 89%), improved the quality of life (MLHFQ score) (MD: -6.83, P = 0.003, I2 = 67%), elevated 6MWD (MD: 15.92, P = 0.006, I2 = 76%), and diminished the level NT-proBNP (MD: -44.19, P < 0.00001, I2 = 75%), but had no significant difference in adverse events [25.81% (310/1201) vs. 30.25% (347/1147), RR: 0.81, 95% CI: 0.65-1.01, P = 0.06, I2 = 55%]. Catheter ablation as rhythm control strategy substantially enhances the survival rate, reduces HF re-hospitalization, increases the rate of sinus rhythm maintenance, improves the left ventricular function and the quality of life for AF patients with HF, and has similar safety, compared with medical therapy. The rhythm control by catheter ablation may be a better strategy for the AF patients with HF.

Targeting PRL phosphatases in hematological malignancies.

INTRODUCTION: Phosphatase of regenerating liver (PRL) family proteins, also known as protein tyrosine phosphatase 4A (PTP4A), have been implicated in many types of cancers. The PRL family of phosphatases consists of three members, PRL1, PRL2, and PRL3. PRLs have been shown to harbor oncogenic potentials and are highly expressed in a variety of cancers. Given their roles in cancer progression and metastasis, PRLs are potential targets for anticancer therapies. However, additional studies are needed to be performed to fully understand the roles of PRLs in blood cancers. AREAS COVERED: In this review, we will summarize recent studies of PRLs in normal and malignant hematopoiesis, the role of PRLs in regulating various signaling pathways, and the therapeutic potentials of targeting PRLs in hematological malignancies. We will also discuss how to improve current PRL inhibitors for cancer treatment. EXPERT OPINION: Although PRL inhibitors show promising therapeutic effects in preclinical studies of different types of cancers, moving PRL inhibitors from bench to bedside is still challenging. More potent and selective PRL inhibitors are needed to target PRLs in hematological malignancies and improve treatment outcomes.

A novel micellular fluorogenic substrate for quantitating the activity of 1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase gamma (PLCγ) enzymes.

The activities of the phospholipase C gamma (PLCγ) 1 and 2 enzymes are essential for numerous cellular processes. Unsurprisingly, dysregulation of PLCγ1 or PLCγ2 activity is associated with multiple maladies including immune disorders, cancers, and neurodegenerative diseases. Therefore, the modulation of either of these two enzymes has been suggested as a therapeutic strategy to combat these diseases. To aid in the discovery of PLCγ family enzyme modulators that could be developed into therapeutic agents, we have synthesized a high-throughput screening-amenable micellular fluorogenic substrate called C16CF3-coumarin. Herein, the ability of PLCγ1 and PLCγ2 to enzymatically process C16CF3-coumarin was confirmed, the micellular assay conditions were optimized, and the kinetics of the reaction were determined. A proof-of-principle pilot screen of the Library of Pharmacologically Active Compounds 1280 (LOPAC1280) was performed. This new substrate allows for an additional screening methodology to identify modulators of the PLCγ family of enzymes.

Lattice dynamics and heat transport in zeolitic imidazolate framework glasses.

The glassy state of zeolitic imidazolate frameworks (ZIFs) has shown great potential for energy-related applications, including solid electrolytes. However, their thermal conductivity (κ), an essential parameter influencing thermal dissipation, remains largely unexplored. In this work, using a combination of experiments, atomistic simulations, and lattice dynamics calculations, we investigate κ and the underlying heat conduction mechanism in ZIF glasses with varying ratios of imidazolate (Im) to benzimidazolate (bIm) linkers. The substitution of bIm for Im tunes the node-linker couplings but exhibits only a minor impact on the average diffusivity of low-frequency lattice modes. On the other hand, the linker substitution induces significant volume expansion, which, in turn, suppresses the contributions from lattice vibrations to κ, leading to decreased total heat conduction. Furthermore, spatial localization of internal high-frequency linker vibrations is promoted upon substitution, reducing their mode diffusivities. This is ascribed to structural deformations of the bIm units in the glasses. Our work unveils the detailed influences of linker substitution on the dual heat conduction characteristics of ZIF glasses and guides the κ regulation of related hybrid materials in practical applications.

Drugging Protein Tyrosine Phosphatases through Targeted Protein Degradation.

Protein tyrosine phosphatases (PTPs) are an important class of enzymes that regulate protein tyrosine phosphorylation levels of a large variety of proteins in cells. Anomalies in protein tyrosine phosphorylation have been associated with the development of numerous human diseases, leading to a heightened interest in PTPs as promising targets for drug development. However, therapeutic targeting of PTPs has faced skepticism about their druggability. Besides the conventional small molecule inhibitors, proteolysis-targeting chimera (PROTAC) technology offers an alternative approach to target PTPs. PROTAC molecules utilize the ubiquitin-proteasome system to degrade specific proteins and have unique advantages compared with inhibitors: 1) PROTACs are highly efficient and can work at much lower concentrations than that expected based on their biophysical binding affinity; 2) PROTACs may achieve higher selectivity for the targeted protein than that dictated by their binding affinity alone; and 3) PROTACs may engage any region of the target protein in addition to the functional site. This review focuses on the latest advancement in the development of targeted PTP degraders and deliberates on the obstacles and prospective paths of harnessing this technology for therapeutic targeting of the PTPs.

Tolerability and effectiveness of beta-blockers in patients with cardiac amyloidosis: A systematic review and meta-analysis.

OBJECTIVE: This systematic review aimed to assess the tolerability of patients with cardiac amyloidosis (CA) to beta-blockers (BBs) and evaluate its association with adverse outcomes. METHODS: We performed a comprehensive search from January 1, 2000 to October 20, 2023. Studies examining BB use and tolerance or the relationship between BB use and outcomes in patients with CA were included. Pooled adjusted hazard ratios (aHRs) for all-cause mortality were calculated using random- and fixed-effects models. RESULTS: Eight observational studies involving 4002 patients with CA (87.5% with transthyretin CA [ATTR-CA] and 12.5% with immunoglobulin light chain CA [AL-CA]) were assessed. BBs were used by 52.5% of the patients. However, 26.3% of the patients discontinued BBs because of hypotension, bradycardia, or fatigue. Regarding the association between BB use and all-cause death, four studies were identified that included 2874 patients with ATTR-CA and 16 patients with AL-CA. The meta-analysis revealed no apparent relationship between BB use and all-cause mortality (pooled aHR = 0.78, 95% confidence interval (CI) = 0.40-1.51). Two studies on patients with ATTR-CA found no impact of BB use on all-cause mortality in the subgroup with left ventricular ejection fraction (LVEF) > 40%, but conflicting results exist for those with LVEF ≤40% (pooled aHR = 0.78, 95% CI = 0.40-1.54). CONCLUSION: The limited number of observational studies that predominantly enrolled patients with ATTR-CA showed that BBs were used in almost half of the patients with CA, with varying tolerability. However, no significant association was observed between BB use and all-cause mortality.

Discovery of flavone-derivatives as the new skeleton of transient receptor potential vanilloid 3 channel antagonists.

Transient receptor potential vanilloid 3 (TRPV3) channel is a temperature-sensitive and Ca2+-permeable nonselective cation channel, which is abundantly expressed in skin keratinocyte and plays an important role in skin homeostasis and repair. However, only a few TRPV3 inhibitors were reported. Few selective and potent modulators of the TRPV3 channel have hindered the progress of the investigation and clinical application. TRPV3 channel research still faces challenges and requires the new inhibitors. Flavonoids are a kind of natural compounds with various biological and pharmacological activities including anti-inflammatory and anti allergic effects, which is associated with some physiological effects mediated by TRPV3 channel. Herein, our group designed and synthesized a range of flavone derivatives, and investigated their inhibitory properties on the human TRPV3 channel by electrophysiology technique. Then, we identified a new potent TRPV3 antagonist 2d with IC50 of 0.62 µM. It also showed good selectivity on TRPV1, TRPV4, TRPA1 and TRPM8.

PTPN9 dephosphorylates FGFR2 pY656/657 through interaction with ACAP1 and ameliorates pemigatinib effect in cholangiocarcinoma.

ABSTRACT AND AIM: Cholangiocarcinoma (CCA) is a highly aggressive and lethal cancer that originates from the biliary epithelium. Systemic treatment options for CCA are currently limited, and the first targeted drug of CCA, pemigatinib, emerged in 2020 for CCA treatment by inhibiting FGFR2 phosphorylation. However, the regulatory mechanism of FGFR2 phosphorylation is not fully elucidated. APPROACH AND RESULTS: Here we screened the FGFR2-interacting proteins and showed that protein tyrosine phosphatase (PTP) N9 interacts with FGFR2 and negatively regulates FGFR2 pY656/657 . Using phosphatase activity assays and modeling the FGFR2-PTPN9 complex structure, we identified FGFR2 pY656/657 as a substrate of PTPN9, and found that sec. 14p domain of PTPN9 interacts with FGFR2 through ACAP1 mediation. Coexpression of PTPN9 and ACAP1 indicates a favorable prognosis for CCA. In addition, we identified key amino acids and motifs involved in the sec. 14p-APCP1-FGFR2 interaction, including the "YRETRRKE" motif of sec. 14p, Y471 of PTPN9, as well as the PH and Arf-GAP domain of ACAP1. Moreover, we discovered that the FGFR2 I654V substitution can decrease PTPN9-FGFR2 interaction and thereby reduce the effectiveness of pemigatinib treatment. Using a series of in vitro and in vivo experiments including patient-derived xenografts (PDX), we showed that PTPN9 synergistically enhances pemigatinib effectiveness and suppresses CCA proliferation, migration, and invasion by inhibiting FGFR2 pY656/657 . CONCLUSIONS: Our study identifies PTPN9 as a negative regulator of FGFR2 phosphorylation and a synergistic factor for pemigatinib treatment. The molecular mechanism, oncogenic function, and clinical significance of the PTPN9-ACAP1-FGFR2 complex are revealed, providing more evidence for CCA precision treatment.

PRL2 Phosphatase Promotes Oncogenic KIT Signaling in Leukemia Cells through Modulating CBL Phosphorylation.

Receptor tyrosine kinase KIT is frequently activated in acute myeloid leukemia (AML). While high PRL2 (PTP4A2) expression is correlated with activation of SCF/KIT signaling in AML, the underlying mechanisms are not fully understood. We discovered that inhibition of PRL2 significantly reduces the burden of oncogenic KIT-driven leukemia and extends leukemic mice survival. PRL2 enhances oncogenic KIT signaling in leukemia cells, promoting their proliferation and survival. We found that PRL2 dephosphorylates CBL at tyrosine 371 and inhibits its activity toward KIT, leading to decreased KIT ubiquitination and enhanced AKT and ERK signaling in leukemia cells. IMPLICATIONS: Our studies uncover a novel mechanism that fine-tunes oncogenic KIT signaling in leukemia cells and will likely identify PRL2 as a novel therapeutic target in AML with KIT mutations.

Inhibition of PRL2 Upregulates PTEN and Attenuates Tumor Growth in Tp53-deficient Sarcoma and Lymphoma Mouse Models.

The phosphatases of regenerating liver (PRL) are oncogenic when overexpressed. We previously found that PRL2 deletion increases PTEN, decreases Akt activity, and suppresses tumor development in a partial Pten-deficient mouse model. The current study aims to further establish the mechanism of PTEN regulation by PRL2 and expand the therapeutic potential for PTEN augmentation mediated by PRL2 inhibition in cancers initiated without PTEN alteration. The TP53 gene is the most mutated tumor suppressor in human cancers, and heterozygous or complete deletion of Tp53 in mice leads to the development of sarcomas and thymic lymphomas, respectively. There remains a lack of adequate therapies for the treatment of cancers driven by Tp53 deficiency or mutations. We show that Prl2 deletion leads to PTEN elevation and attenuation of Akt signaling in sarcomas and lymphomas developed in Tp53 deficiency mouse models. This results in increased survival and reduced tumor incidence because of impaired tumor cell proliferation. In addition, inhibition of PRL2 with a small-molecule inhibitor phenocopies the effect of genetic deletion of Prl2 and reduces Tp53 deficiency-induced tumor growth. Taken together, the results further establish PRL2 as a negative regulator of PTEN and highlight the potential of PRL2 inhibition for PTEN augmentation therapy in cancers with wild-type PTEN expression. SIGNIFICANCE: Prl2 deletion attenuates Tp53 deficiency-induced tumor growth by increasing PTEN and reducing Akt activity. Targeting Tp53-null lymphoma with PRL inhibitors lead to reduced tumor burden, providing a therapeutic approach via PTEN augmentation.

High-Throughput Discovery and Characterization of Covalent Inhibitors for Protein Tyrosine Phosphatases.

Covalent inhibition has gained increasing interest in targeting the undruggable protein tyrosine phosphatases (PTPs). However, a systematic method for discovering and characterizing covalent PTP inhibitors has yet to be established. Here, we describe a workflow involving high-throughput screening of covalent fragment libraries and a novel biochemical assay that enables the acquisition of kinetics parameters of PTP inhibition by covalent inhibitors with higher throughput.

High-temperature and high-pressure thermal property measurements of SiO2 crystals.

The investigation of materials' behavior under high-temperature and high-pressure conditions, such as the correlation with structural characteristics and thermal properties, holds significant importance. However, the challenges associated with the experimental implementation have, to a certain extent, constrained such research endeavors. We utilized the ultrafast laser based non-contact thermal measurement method combined with an externally heated moissanite-anvil-cell to characterize the thermal conductivity of [10-10] oriented SiO2 crystals under high temperature (300-830 K) and high pressure (0-15 GPa) conditions. We investigated the impact of extreme conditions on the microstructure from both Raman spectroscopy and thermal perspectives. The presence of kinetic hindrances associated with the transformation of α-quartz to coesite and stishovite was identified and confirmed. It expands the comprehension and application of the SiO2 pressure-temperature phase diagram in this range and provides insights into the intricate relationship between extreme environments and material structure formation through the analysis of thermal characteristics.

Protein tyrosine phosphatases as emerging targets for cancer immunotherapy.

Contemporary strategies in cancer immunotherapy, despite remarkable success, remain constrained by inherent limitations such as suboptimal patient responses, the emergence of drug resistance, and the manifestation of pronounced adverse effects. Consequently, the need for alternative strategies for immunotherapy becomes clear. Protein tyrosine phosphatases (PTPs) wield a pivotal regulatory influence over an array of essential cellular processes. Substantial research has underscored the potential in targeting PTPs to modulate the immune responses and/or regulate antigen presentation, thereby presenting a novel paradigm for cancer immunotherapy. In this review, we focus on recent advances in genetic and biological validation of several PTPs as emerging targets for immunotherapy. We also highlight recent development of small molecule inhibitors and degraders targeting these PTPs as novel cancer immunotherapeutic agents.

Laminarin Reduces Cholesterol Uptake and NPC1L1 Protein Expression in High-Fat Diet (HFD)-Fed Mice.

Aberrantly high dietary cholesterol intake and intestinal cholesterol uptake lead to dyslipidemia, one of the risk factors for cardiovascular diseases (CVDs). Based on previous studies, laminarin, a polysaccharide found in brown algae, has hypolipidemic activity, but its underlying mechanism has not been elucidated. In this study, we investigated the effect of laminarin on intestinal cholesterol uptake in vitro, as well as the lipid and morphological parameters in an in vivo model of high-fat diet (HFD)-fed mice, and addressed the question of whether Niemann-Pick C1-like 1 protein (NPC1L1), a key transporter mediating dietary cholesterol uptake, is involved in the mechanistic action of laminarin. In in vitro studies, BODIPY-cholesterol-labeled Caco-2 cells were examined using confocal microscopy and a fluorescence reader. The results demonstrated that laminarin inhibited cholesterol uptake into Caco-2 cells in a concentration-dependent manner (EC50 = 20.69 µM). In HFD-fed C57BL/6J mice, laminarin significantly reduced the serum levels of total cholesterol (TC), total triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C). It also decreased hepatic levels of TC, TG, and total bile acids (TBA) while promoting the excretion of fecal cholesterol. Furthermore, laminarin significantly reduced local villous damage in the jejunum of HFD mice. Mechanistic studies revealed that laminarin significantly downregulated NPC1L1 protein expression in the jejunum of HFD-fed mice. The siRNA-mediated knockdown of NPC1L1 attenuated the laminarin-mediated inhibition of cholesterol uptake in Caco-2 cells. This study suggests that laminarin significantly improves dyslipidemia in HFD-fed mice, likely by reducing cholesterol uptake through a mechanism that involves the downregulation of NPC1L1 expression.

SHIP1 therapeutic target enablement: Identification and evaluation of inhibitors for the treatment of late-onset Alzheimer's disease.

INTRODUCTION: The risk of developing Alzheimer's disease is associated with genes involved in microglial function. Inositol polyphosphate-5-phosphatase (INPP5D), which encodes Src homology 2 (SH2) domain-containing inositol polyphosphate 5-phosphatase 1 (SHIP1), is a risk gene expressed in microglia. Because SHIP1 binds receptor immunoreceptor tyrosine-based inhibitory motifs (ITIMs), competes with kinases, and converts PI(3,4,5)P3 to PI(3,4)P2, it is a negative regulator of microglia function. Validated inhibitors are needed to evaluate SHIP1 as a potential therapeutic target. METHODS: We identified inhibitors and screened the enzymatic domain of SHIP1. A protein construct containing two domains was used to evaluate enzyme inhibitor potency and selectivity versus SHIP2. Inhibitors were tested against a construct containing all ordered domains of the human and mouse proteins. A cellular thermal shift assay (CETSA) provided evidence of target engagement in cells. Phospho-AKT levels provided further evidence of on-target pharmacology. A high-content imaging assay was used to study the pharmacology of SHIP1 inhibition while monitoring cell health. Physicochemical and absorption, distribution, metabolism, and excretion (ADME) properties were evaluated to select a compound suitable for in vivo studies. RESULTS: SHIP1 inhibitors displayed a remarkable array of activities and cellular pharmacology. Inhibitory potency was dependent on the protein construct used to assess enzymatic activity. Some inhibitors failed to engage the target in cells. Inhibitors that were active in the CETSA consistently destabilized the protein and reduced pAKT levels. Many SHIP1 inhibitors were cytotoxic either at high concentration due to cell stress or they potently induced cell death depending on the compound and cell type. One compound activated microglia, inducing phagocytosis at concentrations that did not result in significant cell death. A pharmacokinetic study demonstrated brain exposures in mice upon oral administration. DISCUSSION: 3-((2,4-Dichlorobenzyl)oxy)-5-(1-(piperidin-4-yl)-1H-pyrazol-4-yl) pyridine activated primary mouse microglia and demonstrated exposures in mouse brain upon oral dosing. Although this compound is our recommended chemical probe for investigating the pharmacology of SHIP1 inhibition at this time, further optimization is required for clinical studies. Highlights: Cellular thermal shift assay (CETSA) and signaling (pAKT) assays were developed to provide evidence of src homology 2 (SH2) domain-contaning inositol phosphatase 1 (SHIP1) target engagement and on-target activity in cellular assays.A phenotypic high-content imaging assay with simultaneous measures of phagocytosis, cell number, and nuclear intensity was developed to explore cellular pharmacology and monitor cell health.SHIP1 inhibitors demonstrate a wide range of activity and cellular pharmacology, and many reported inhibitors are cytotoxic.The chemical probe 3-((2,4-dichlorobenzyl)oxy)-5-(1-(piperidin-4-yl)-1H-pyrazol-4-yl) pyridine is recommended to explore SHIP1 pharmacology.

Discovery of a selective TC-PTP degrader for cancer immunotherapy.

T-cell protein tyrosine phosphatase (TC-PTP), encoded by PTPN2, has emerged as a promising target for cancer immunotherapy. TC-PTP deletion in B16 melanoma cells promotes tumor cell antigen presentation, while loss of TC-PTP in T-cells enhances T-cell receptor (TCR) signaling and stimulates cell proliferation and activation. Therefore, there is keen interest in developing TC-PTP inhibitors as novel immunotherapeutic agents. Through rational design and systematic screening, we discovered the first highly potent and selective TC-PTP PROTAC degrader, TP1L, which induces degradation of TC-PTP in multiple cell lines with low nanomolar DC50s and >110-fold selectivity over the closely related PTP1B. TP1L elevates the phosphorylation level of TC-PTP substrates including pSTAT1 and pJAK1, while pJAK2, the substrate of PTP1B, is unaffected by the TC-PTP degrader. TP1L also intensifies interferon gamma (IFN-γ) signaling and increases MHC-I expression. In Jurkat cells, TP1L activates TCR signaling through increased phosphorylation of LCK. Furthermore, in a CAR-T cell and KB tumor cell co-culture model, TP1L enhances CAR-T cell mediated tumor killing efficacy through activation of the CAR-T cells. Thus, we surmise that TP1L not only provides a unique opportunity for in-depth interrogation of TC-PTP biology but also serves as an excellent starting point for the development of novel immunotherapeutic agents targeting TC-PTP.