参考文献

Currently approved immune checkpoint inhibitor therapies targeting the PD-1 and CTLA-4 receptor pathways are powerful treatment options for certain cancers; however,most patients across cancer types still fail to respond. Consequently,there is interest in discovering and blocking alternative pathways that mediate immune suppression. One such mechanism is an upregulation of sialoglycans in malignancy,which has been recently shown to inhibit immune cell activation through multiple mechanisms and therefore represents a targetable glycoimmune checkpoint. Since these glycans are not canonically druggable,we designed an $\alpha$HER2 antibody-sialidase conjugate that potently and selectively strips diverse sialoglycans from breast cancer cells. In syngeneic breast cancer models,desialylation enhanced immune cell infiltration and activation and prolonged the survival of mice,an effect that was dependent on expression of the Siglec-E checkpoint receptor found on tumor-infiltrating myeloid cells. Thus,antibody-sialidase conjugates represent a promising modality for glycoimmune checkpoint therapy. View Publication

Tumor-associated macrophages (TAM) in the tumor microenvironment (TME) cooperate with cancer stem cells (CSC) to maintain stemness. We recently identified cluster of differentiation 44 (CD44) as a surface marker defining head and neck squamous cell carcinoma (HNSCC) CSC. PI3K-4EBP1-SOX2 activation and signaling regulate CSC properties,yet the upstream molecular control of this pathway and the mechanisms underlying cross-talk between TAM and CSC in HNSCC remain largely unknown. Because CD44 is a molecular mediator in the TME,we propose here that TAM-influenced CD44 signaling could mediate stemness via the PI3K-4EBP1-SOX2 pathway,possibly by modulating availability of hyaluronic acid (HA),the main CD44 ligand. HNSCC IHC was used to identify TAM/CSC relationships,and in vitro coculture spheroid models and in vivo mouse models were used to identify the influence of TAMs on CSC function via CD44. Patient HNSCC-derived TAMs were positively and negatively associated with CSC marker expression at noninvasive and invasive edge regions,respectively. TAMs increased availability of HA and increased cancer cell invasion. HA binding to CD44 increased PI3K-4EBP1-SOX2 signaling and the CSC fraction,whereas CD44-VCAM-1 binding promoted invasive signaling by ezrin/PI3K. In vivo,targeting CD44 decreased PI3K-4EBP1-SOX2 signaling,tumor growth,and CSC. TAM depletion in syngeneic and humanized mouse models also diminished growth and CSC numbers. Finally,a CD44 isoform switch regulated epithelial-to-mesenchymal plasticity as standard form of CD44 and CD44v8-10 determined invasive and tumorigenic phenotypes,respectively. We have established a mechanistic link between TAMs and CSCs in HNSCC that is mediated by CD44 intracellular signaling in response to extracellular signals. SIGNIFICANCE: These findings establish a mechanistic link between tumor cell CD44,TAM,and CSC properties at the tumor-stroma interface that can serve as a vital area of focus for target and drug discovery. View Publication

Camostat mesilate (CM),an oral protease inhibitor,has been used clinically for the treatment of chronic pancreatitis in Japan. However,the mechanism by which it operates has not been fully understood. Our aim was to evaluate the therapeutic efficacy of CM in the experimental pancreatic fibrosis model induced by dibutyltin dichloride (DBTC),and we also determined the effect of CM on isolated monocytes and panceatic stellate cells (PSCs). In vivo,chronic pancreatitis was induced in male Lewis rats by single administration of 7 mg/kg DBTC and a special diet containing 1 mg/g CM was fed to the DBTC+CM-treated group from day 7,while the DBTC-treated group rats were fed a standard diet. At days 0,7,14 and 28,the severity of pancreatitis and fibrosis was examined histologically and enzymologically in both groups. In vitro,monocytes were isolated from the spleen of a Lewis rat,and activated with lipopolysaccharide stimulation. Thereafter,the effect of CM on monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-alpha (TNF-alpha) production from monocytes was examined. Subsequently,cultured rat PSCs were exposed to CM and tested to see whether their proliferation,MCP-1 production and procollagen alpha1 messenger RNA expression was influenced by CM. In vivo,the oral administration of CM inhibited inflammation,cytokines expression and fibrosis in the pancreas. The in vitro study revealed that CM inhibited both MCP-1 and TNF-alpha production from monocytes,and proliferation and MCP-1 production from PSCs. However,procollagen alpha1 expression in PSCs was not influenced by CM. These results suggest that CM attenuated DBTC-induced rat pancreatic fibrosis via inhibition of monocytes and PSCs activity. View Publication

BACKGROUND Taking into consideration a recent surge of a lung injury condition associated with electronic cigarette use,we devised an in vitro model of sub-chronic exposure of human bronchial epithelial cells (HBECs) in air-liquid interface,to determine deterioration of epithelial cell barrier from sub-chronic exposure to cigarette smoke (CS),e-cigarette aerosol (EC),and tobacco waterpipe exposures (TW). METHODS Products analyzed include commercially available e-liquid,with 0{\%} or 1.2{\%} concentration of nicotine,tobacco blend (shisha),and reference-grade cigarette (3R4F). In one set of experiments,HBECs were exposed to EC (0 and 1.2{\%}),CS or control air for 10 days using 1 cigarette/day. In the second set of experiments,exposure of pseudostratified primary epithelial tissue to TW or control air exposure was performed 1-h/day,every other day,until 3 exposures were performed. After 16-18 h of last exposure,we investigated barrier function/structural integrity of the epithelial monolayer with fluorescein isothiocyanate-dextran flux assay (FITC-Dextran),measurements of trans-electrical epithelial resistance (TEER),assessment of the percentage of moving cilia,cilia beat frequency (CBF),cell motion,and quantification of E-cadherin gene expression by reverse-transcription quantitative polymerase chain reaction (RT-qPCR). RESULTS When compared to air control,CS increased fluorescence (FITC-Dextran assay) by 5.6 times,whereby CS and EC (1.2{\%}) reduced TEER to 49 and 60{\%} respectively. CS and EC (1.2{\%}) exposure reduced CBF to 62 and 59{\%},and cilia moving to 47 and 52{\%},respectively,when compared to control air. CS and EC (1.2{\%}) increased cell velocity compared to air control by 2.5 and 2.6 times,respectively. The expression of E-cadherin reduced to 39{\%} of control air levels by CS exposure shows an insight into a plausible molecular mechanism. Altogether,EC (0{\%}) and TW exposures resulted in more moderate decreases in epithelial integrity,while EC (1.2{\%}) substantially decreased airway epithelial barrier function comparable with CS exposure. CONCLUSIONS The results support a toxic effect of sub-chronic exposure to EC (1.2{\%}) as evident by disruption of the bronchial epithelial cell barrier integrity,whereas further research is needed to address the molecular mechanism of this observation as well as TW and EC (0{\%}) toxicity in chronic exposures. View Publication

Studies with peptide-based and macromolecular inhibitors of the caspase family of cysteine proteases have helped to define a central role for these enzymes in inflammation and mammalian apoptosis. A clear interpretation of these studies has been compromised by an incomplete understanding of the selectivity of these molecules. Here we describe the selectivity of several peptide-based inhibitors and the coxpox serpin CrmA against 10 human caspases. The peptide aldehydes that were examined (Ac-WEHD-CHO,Ac-DEVD-CHO,Ac-YVAD-CHO,t-butoxycarbonyl-IETD-CHO,and t-butoxycarbonyl-AEVD-CHO) included several that contain the optimal tetrapeptide recognition motif for various caspases. These aldehydes display a wide range of selectivities and potencies against these enzymes,with dissociation constants ranging from 75 pM to {\textgreater}10 microM. The halomethyl ketone benzyloxycarbonyl-VAD fluoromethyl ketone is a broad specificity irreversible caspase inhibitor,with second-order inactivation rates that range from 2.9 x 10(2) M-1 s-1 for caspase-2 to 2.8 x 10(5) M-1 s-1 for caspase-1. The results obtained with peptide-based inhibitors are in accord with those predicted from the substrate specificity studies described earlier. The cowpox serpin CrmA is a potent (Ki {\textless} 20 nM) and selective inhibitor of Group I caspases (caspase-1,-4,and -5) and most Group III caspases (caspase-8,-9,and -10),suggesting that this virus facilitates infection through inhibition of both apoptosis and the host inflammatory response. View Publication

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PURPOSE A major clinical problem in the treatment of breast cancer is the inherent and acquired resistance to antiestrogen therapy. In this study,we sought to determine whether antiprogestin treatment,used as a monotherapy or in combination with antiestrogen therapy,induced growth arrest and active cell death in antiestrogen-resistant breast cancer cells. EXPERIMENTAL DESIGN MCF-7 sublines were established from independent clonal isolations performed in the absence of drug selection and tested for their response to the antiestrogens 4-hydroxytamoxifen (4-OHT) and ICI 182,780 (fulvestrant),and the antiprogestin mifepristone (MIF). The cytostatic (growth arrest) effects of the hormones were assessed with proliferation assays,cell counting,flow cytometry,and a determination of the phosphorylation status of the retinoblastoma protein. The cytotoxic (apoptotic) effects were analyzed by assessing increases in caspase activity and cleavage of poly(ADP-ribose) polymerase. RESULTS All of the clonally derived MCF-7 sublines expressed estrogen receptor and progesterone receptor but showed a wide range of antiestrogen sensitivity,including resistance to physiological levels of 4-OHT. Importantly,all of the clones were sensitive to the antiprogestin MIF,whether used as a monotherapy or in combination with 4-OHT. MIF induced retinoblastoma activation,G(1) arrest,and apoptosis preceded by caspase activation. CONCLUSIONS We demonstrate that: (a) estrogen receptor(+)progesterone receptor(+),4-OHT-resistant clonal variants can be isolated from an MCF-7 cell line in the absence of antiestrogen selection; and (b) MIF and MIF plus 4-OHT combination therapy induces growth arrest and active cell death of the antiestrogen-resistant breast cancer cells. These preclinical findings show potential for a combined hormonal regimen of an antiestrogen and an antiprogestin to combat the emergence of antiestrogen-resistant breast cancer cells and,ultimately,improve the therapeutic index of antiestrogen therapy. View Publication

Targeting proteins within the N-type voltage-gated calcium channel (CaV2.2) complex has proven to be an effective strategy for developing novel pain therapeutics. We describe a novel peptide aptamer derived from the collapsin response mediator protein 2 (CRMP2),a CaV2.2-regulatory protein. Addition of a 14-carbon myristate group to the peptide (myr-tat-CBD3) tethered it to the membrane of primary sensory neurons near surface CaV2.2. Pull-down studies demonstrated that myr-tat-CBD3 peptide interfered with the CRMP2-CaV2.2 interaction. Quantitative confocal immunofluorescence revealed a pronounced reduction of CaV2.2 trafficking after myr-tat-CBD3 treatment and increased efficiency in disrupting CRMP2-CaV2.2 colocalization compared with peptide tat-CBD3. Consequently,myr-tat-CBD3 inhibited depolarization-induced calcium influx in sensory neurons. Voltage clamp electrophysiology experiments revealed a reduction of Ca,but not Na,currents in sensory neurons after myr-tat-CBD3 exposure. Current clamp electrophysiology experiments demonstrated a reduction in excitability of small-diameter dorsal root ganglion neurons after exposure to myr-tat-CBD3. Myr-tat-CBD3 was effective in significantly attenuating carrageenan-induced thermal hypersensitivity and reversing thermal hypersensitivity induced by a surgical incision of the plantar surface of the rat hind paw,a model of postoperative pain. These effects are compared with those of tat-CBD3-the nonmyristoylated tat-conjugated CRMP2 peptide as well as scrambled versions of CBD3 and CBD3-lacking control peptides. Our results demonstrate that the myristoyl tag enhances intracellular delivery and local concentration of the CRMP2 peptide aptamer near membrane-delimited calcium channels resulting in pronounced interference with the calcium channel complex,superior suppression of calcium influx,and better antinociceptive potential. View Publication

Increased extracellular sodium activates Th17 cells,which provide protection from bacterial and fungal infections. Whilst high salt diets have been shown to worsen autoimmune disease,the immunological consequences of clinical salt depletion are unknown. Here,we investigate immunity in patients with inherited salt-losing tubulopathies (SLT). Forty-seven genotyped SLT patients (with Bartter,Gitelman or EAST Syndromes) are recruited. Clinical features of dysregulated immunity are recorded with a standardised questionnaire and immunological investigations of IL-17 responsiveness undertaken. The effects of altering extracellular ionic concentrations on immune responses are then assessed. Patients are hypokalaemic and hypomagnesaemic,with reduced interstitial sodium stores determined by 23Na-magnetic resonance imaging. SLT patients report increased mucosal infections and allergic disease compared to age-matched controls. Aligned with their clinical phenotype,SLT patients have an increased ratio of Th2:Th17 cells. SLT Th17 and Tc17 polarisation is reduced in vitro,yet STAT1 and STAT3 phosphorylation and calcium flux following T cell activation are unaffected. In control cells,the addition of extracellular sodium (+40 mM),potassium (+2 mM),or magnesium (+1 mM) reduces Th2:Th17 ratio and augments Th17 polarisation. Our results thus show that the ionic environment typical in SLT impairs IL-17 immunity,but the intracellular pathways that mediate salt-driven Th17 polarisation are intact and in vitro IL-17 responses can be reinvigorated by increasing extracellular sodium concentration. Whether better correction of extracellular ions can rescue the immunophenotype in vivo in SLT patients remains unknown. View Publication

Eltrombopag is a first-in-class,orally bioavailable,small-molecule,nonpeptide agonist of the thrombopoietin receptor (TpoR),which is being developed as a treatment for thrombocytopenia of various etiologies. In vitro studies have demonstrated that the activity of eltrombopag is dependent on expression of TpoR,which activates the signaling transducers and activators of transcription (STAT) and mitogen-activated protein kinase signal transduction pathways. The objective of this preclinical study is to determine if eltrombopag interacts selectively with the TpoR to facilitate megakaryocyte differentiation in platelets. Functional thrombopoietic activity was demonstrated by the proliferation and differentiation of primary human CD34(+) bone marrow cells into CD41(+) megakaryocytes. Measurements in platelets in several species indicated that eltrombopag specifically activates only the human and chimpanzee STAT pathways. The in vivo activity of eltrombopag was demonstrated by an increase of up to 100{\%} in platelet numbers when administered orally (10 mg/kg per day for 5 days) to chimpanzees. In conclusion,eltrombopag interacts selectively with the TpoR without competing with Tpo,leading to the increased proliferation and differentiation of human bone marrow progenitor cells into megakaryocytes and increased platelet production. These results suggest that eltrombopag and Tpo may be able to act additively to increase platelet production. View Publication

BACKGROUND AND AIM An oral trypsin inhibitor,camostat (CM),has a beneficial effect on chronic pancreatitis,but its mechanism is not yet fully understood. Recently,pancreatic stellate cells (PSC) have been reported to play an essential role in pancreatic fibrosis. An experimental model of pancreatic fibrosis induced by a superoxide dismutase (SOD) inhibitor (diethyldithiocarbamate [DDC]) was developed in rats. Thus,the effect of an oral trypsin inhibitor on pancreatic fibrosis and PSC was investigated. METHODS Pancreatic fibrosis was induced in rats using DDC (DDC rats). DDC + CM rats were administered DDC,and subsequently were fed a diet containing CM. Immunohistochemistry of the pancreas was performed with monoclonal anti-alpha-smooth muscle actin (alpha-SMA) antibody and anti-desmin antibody. RESULTS The DDC rats showed a significant increase in alpha-SMA-positive cells or desmin-positive cells compared with control rats. These significant increases in the fibrotic area improved after treatment with CM. The level of prolyl hydroxylase in the pancreas,which significantly increased as a result of DDC,decreased after treatment with CM. CONCLUSION Camostat has a beneficial effect on pancreatic fibrosis induced by the administration of a SOD inhibitor,which inhibits the proliferation and activation of PSC. View Publication

Many tumors become addicted to autophagy for survival,suggesting inhibition of autophagy as a potential broadly applicable cancer therapy. ULK1/Atg1 is the only serine/threonine kinase in the core autophagy pathway and thus represents an excellent drug target. Despite recent advances in the understanding of ULK1 activation by nutrient deprivation,how ULK1 promotes autophagy remains poorly understood. Here,we screened degenerate peptide libraries to deduce the optimal ULK1 substrate motif and discovered 15 phosphorylation sites in core autophagy proteins that were verified as in vivo ULK1 targets. We utilized these ULK1 substrates to perform a cell-based screen to identify and characterize a potent ULK1 small molecule inhibitor. The compound SBI-0206965 is a highly selective ULK1 kinase inhibitor in vitro and suppressed ULK1-mediated phosphorylation events in cells,regulating autophagy and cell survival. SBI-0206965 greatly synergized with mechanistic target of rapamycin (mTOR) inhibitors to kill tumor cells,providing a strong rationale for their combined use in the clinic. View Publication