Blockade Of Signaling Pathway Research Articles

The Role of HSP70 in Cancer and its Exploitation as a Therapeutic Target.

Sustained proliferation and genetic instability of cancer cells are associated with enhanced production of mutated and conformationally unstable proteins. Excessive proteosynthesis along with increased metabolic turnover generates stress conditions that cancer cells must permanently compensate for. Tumor cells thus become dependent on the maintenance of protein homeostasis, which involves protein quality control, folding, transport and stabilization. These tasks are provided by molecular chaperones, predominantly the stress proteins HSP70 and HSP90. Their expression and activity is increased in all malignant tumors, where they associate with their cochaperones to form large multiprotein complexes. HSP70 and HSP90 maintain the malignant phenotype because they facilitate the folding of numerous oncogenic proteins, maintain proliferative potential, and inhibit apoptosis. In this regard, heat-shock proteins represent an important target for cancer therapy because their inactivation results in the simultaneous blockade of multiple signaling pathways. Although several specific HSP90 inhibitors have been developed in the past decade, their antitumor activity as single agents is limited due to the induction of HSP70, which enables cell survival. Inhibitors of HSP70 thus present new possibilities for targeting proteostatic mechanisms in cancer cells. The aim of this article is to summarize information on the structure of HSP70 and its role in maintaining protein homeostasis in normal and cancer cells. The mechanisms of HSP70 inhibition by low-molecular weight compounds and their application in targeted antitumor therapy are also described. Key words: HSP70 - stress proteins - molecular chaperons - cellular stress - tumours - protein folding This work was supported by the project MEYS - NPS I - LO1413. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Accepted: 16. 08. 2018.

Dual TGF-β and PD-1 blockade synergistically enhances MAGE-A3-specific CD8+ T cell response in esophageal squamous cell carcinoma.

PD-1 is highly expressed on tumor-infiltrated antigen-specific T cells and limit the antitumor function. Blocking of PD-1/PD-L1 signaling has shown unprecedented curative efficacies in patients with advanced cancer. However, only a limited population of patients benefited from such therapies. Our study aimed to explore biological properties, functional regulation and reversal of MAGE-A3-specific CD8+ T cells in patients with esophageal squamous cell carcinoma (ESCC). The underlying principle of deficiency and restoring MAGE-A3-specific CD8+ T cells function in tumor microenvironment (TME) was evaluated. MAGE-A3-specific CD8+ T cells could lyse HLA-A2+ /MAGE-A3+ tumor cells. Tetramer+ T cell frequency was higher in elder patients, but lower in patients with lymph node metastasis and late tumor stage (p < 0.05). CD107ahigh expression on functional T cells was an independent prognostic factor in Cox regression analysis. PD-1 was highly expressed on dysfunctional antigen-specific CD8+ T cells and tumor infiltrating T lymphocytes (p < 0.05). Myeloid-derived suppressor cells (MDSCs) derived-TGF-β mediated PD-1high expression on CD8+ T cells, which led to be resistance to PD-1/PD-L1 blockade in TME. Dual PD-1/PD-L1 and TGF-β signaling pathway blockades synergistically restored the function and antitumor ability of antigen-specific CD8+ T cells in vitro/vivo assay. The presence of functional MAGE-A3-specific CD8+ T cells had an independent prognostic impact on survival of patients with ESCC. Furthermore, MDSCs-derived TGF-β increased PD-1 expression on T cells and decreased the sensitivity to PD-1/PD-L1 blockade. Combining T cell-based therapy with dual PD-1/PD-L1 and TGF-β signaling pathway blockade could be considered a promising strategy for cancer treatment.

Treatment of chronic pruritus-what is new?

Chronic pruritus is one of the most common and stressful symptoms in medicine. Therapy remains agreat challenge because of the lack of approved therapies. In the recent past agreater understanding of the pathogenesis has enabled the results to be translated into new forms of therapy. The various therapies target awide range of points in the pruritic cascade-from blockade of intracellular and intercellular signaling pathways in the skin to the modulation of neurotransmission. This article provides asummary of current therapeutic options based on the current S2K guideline and gives an overview about recent developments in antipruritic treatments.

Astilbin ameliorates pulmonary fibrosis via blockade of Hedgehog signaling pathway

Background and objectiveThe nature of pulmonary fibrosis involves inadequate repair of the epithelial cell barrier accompanied by impaired regulation of the fibroblast. Moreover, pulmonary fibrosis currently lacks an effective therapeutic drug. This study targets the protection of the epithelial cell and fibroblast to identify a novel, potentially therapeutic drug (i.e., astilbin). MethodsIn this study, the cytotoxicity of astilbin was firstly detected using CCK-8. A real-time proliferation/migration analysis system was used to test the inhibitory proliferation and migration of astilbin in vitro. The expression of mesenchymal markers and the loss of epithelial cell markers were analyzed to evaluate the antifibrotic activity of astilbin on TGF-β1-treated AEC-II and L929 cells and bleomycin-treated mice. Then, in fibrosis-associated signaling pathways, the regulation of astilbin was tested using RNA sequencing and Cignal Finder 45-Pathway system. Rescue and other experiments were used to confirm this pathway regulation further. ResultsThe data showed that astilbin inhibited proliferation and migration of cell samples. Its treatment resulted in the reduction of pathological score and collagen deposition, with a decrease in α-SMA and Snail and an increase in E-cadherin and SP-C in vivo and in vitro. The fibrosis-associated aberrant genes are some of the most notable components of the Hedgehog signaling pathway. ConclusionsAstilbin ameliorates pulmonary fibrosis via blockade of Hedgehog signaling pathway and has potential therapeutic value for lung fibrosis treatment.

Elucidation on Predominant Pathways Involved in the Differentiation and Mineralization of Odontoblast-Like Cells by Selective Blockade of Mitogen-Activated Protein Kinases.

Aim To analyze the effect of three mitogen-activated protein kinase (MAPK) inhibitors, namely, SB202190 (p38 inhibitor), SP600125 (JNK inhibitor), and PD98059 (ERK inhibitor) in Dex-stimulated MDPC-23 cell differentiation and mineralization. Methods Experiment was divided into five groups, control (cells without Dex and inhibitors treatment), Dex (cells with Dex treatment but without inhibitors), Dex + SB202190, Dex + SP600125, and Dex + PD98059. Cell differentiation was assessed by alkaline phosphatase (ALP) activity assay and real time RT-PCR. Cell mineralization was investigated by alizarin red staining. Results Exposure to SB202190 (20 μM) significantly decreased the mineral deposition in Dex-treated cells as demonstrated by alizarin red staining. Treatment of SP600125 (20 μM) attenuated the mineralization as well, albeit at a lower degree as compared to SB202190 (20 μM). Similarly, SB202190 (20 μM) completely abrogated the ALP activity stimulated by Dex at six days in culture, while no changes were observed with regard to ALP activity in SP600125 (20 μM) and PD98059 (20 μM) treated cells. The upregulation of bone sialoprotein (BSP), ALP, and osteopontin (OPN) in Dex challenged cells was completely inhibited by SB202190. Conclusion Blockade of p38-MAPK signaling pathway resulted in significant inhibition of ALP activity, mineralization, and downregulation of osteogenic markers. The data implicated that p38 signaling pathway plays a critical role in the regulation of MDPC-23 cells differentiation and mineralization.

The Role of Grb2 in Cancer and Peptides as Grb2 Antagonists.

Growth factor receptor-bound protein 2 (Grb2) is a 25 kDa adaptor protein, which was originally discovered to accomplish basic cellular events such as cell growth, cell proliferation, and metabolism. However, recent studies evidenced that Grb2 was largely involved in multiple tumor malignancies. The mature Grb2 is a 217 amino acid sequence, which consists of one Src homology 2 (SH2) domain flanked by two Src homology 3 (SH3) domains. Using these binding motives, the ubiquitously expressed Grb2 acts as an intermediate between cell-surface activated receptors and downstream targets. Consequently, the Grb2 becomes the key element of this oncogenesis and launched a number of defected signaling cascades. Therefore, vast concern of the Grb2 in multiple cancer patterns makes it an attractive therapeutic target. In this review, we have compiled the maximum tumor conformations caused by the involvement of the Grb2, the central role of Grb2 in numerous oncogenic pathways and particular approaches that can be useful to downregulate the Grb2 overexpression. We will discuss in details the activity of different types of novel peptides, their high affinity for the Grb2 protein and blockade of Grb2 mediated signaling pathways by targeting the SH2/SH3 binding sites. There is a three-fold aspect to this review: Grb2 protein introduction, Grb2 protein involvement in cancer, and the role of peptides as Grb2 antagonists. First, Grb2 and compiled maximum tumor conformations induced by Grb2 involvement were introduced. Secondly, several oncogenic pathways of Grb2 involvement and particular approaches potentially useful to downregulate Grb2 overexpression were outlined. The activity of different types of novel peptides for the Grb2 protein was also detailed. Last but not least, the blockade of Grb2-mediated signaling pathways by targeting SH2/SH3 binding sites were summarized. We have epitomized the utmost cancer malignancies caused by abnormal signaling of the Grb2 adaptor molecule. Indeed, Grb2's enormous involvement in the progression and development of different cancers broaden our tactics to build anticancer drug candidates. Depending on the high affinity and increased specificity we have described the major potent peptides which may efficiently target and block the SH2 or SH3 arms of the Grb2. It may be of benefit for developing novel anticancer peptides. However, further work is needed to pinpoint more binding motives of Grb2 to generate efficacious anticancer agents for diverse human cancers in the near future.

Galectin-9 Promotes Human Trophoblast Cell Invasion through Matrix Metalloproteinase-2 and p38 Signaling Pathway

Objective: Adequate extravillous trophoblast (EVT) invasion plays a crucial role in the establishment of successful pregnancy. Insufficient trophoblast migration and invasion can result in defective placentation, which is associated with a number of clinical pathological conditions of pregnancy including spontaneous abortion and preeclampsia. Galectin-9 (Gal-9) has a wide variety of regulatory functions in innate and adaptive immunity during infection, tumor growth, and organ transplantation. Methods: We utilized immortalized human first-trimester EVT cells (HTR8/SVneo) for our functional study. We examined the effects of Gal-9 on viability, proliferation, and invasion of HTR8/SVneo cells, as well as on matrix metalloproteinase-2 (MMP-2) production in HTR8/SVneo cells. Furthermore, we observed the effects of different MAPK-signaling pathway inhibitors on the stimulatory functions of Gal-9 on HTR8/SVneo cells' invasion. Results: We verified the secretion of Gal-9 by trophoblasts and detected a correlation between low levels of Gal-9 and spontaneous abortion. Gal-9 promoted the invasion of HTR8/SVneo cells through its interaction with Tim-3, not CD44, and subsequently increased MMP-2 production. Blockade of p38 signaling pathway inhibited Gal-9 activities in HTR8/SVneo cells. Conclusion: Gal-9 promotes human trophoblast cell invasion through MMP-2 and p38 signaling pathway in a Tim-3-dependent manner.

MiR-143 suppresses the osteogenic differentiation of dental pulp stem cells by inactivation of NF-κB signaling pathway via targeting TNF-α

BackgroundDental pulp stem cells (DPSCs) are multipotent and play an important role in repairing damaged and/or defective dentinogenesis/osteogenesis. Recent studies have documented the implication of miR-143 in osteogenic differentiation of DPSCs. Nevertheless, the detailed mechanisms of miR-143 involved in the osteogenic differentiation of DPSCs remain to be further elaborated. MethodsIsolated DPSCs were incubated with osteogenic differentiation medium to induce osteogenic differentiation. qRT-PCR and western blot were performed to determine the expressions of miR-143 and tumor necrosis factor α (TNF-α). Luciferase reporter assay was used to confirm whether TNF-α was a target of miR-143. Osteogenic differentiation of DPSCs was evaluated by alkaline phosphatase (ALP) activity assay, ALP staining, and western blot analyses of osteogenic-markers including bone morphogenetic protein 2 (BMP2), ALP, runt-related transcription factor 2 (RUNX2) and collagen type I (COLI). ResultsmiR-143 was downregulated and TNF-α was upregulated during osteogenic differentiation of DPSCs. miR-143 posttranscriptionally regulated TNF-α expression in DPSCs by binding to its 3′UTR. miR-143 overexpression suppressed osteogenic differentiation of DPSCs, as demonstrated by the decrease of ALP activity, ALP positive cell ratio, as well as BMP2, ALP, RUNX2, and COLI expressions. Moreover, miR-143 reversed TNF-α-induced osteogenic differentiation of DPSCs. Finally, the osteogenic differentiation of DPSCs induced by miR-143 inhibitor was attenuated following inactivation of nuclear factor kappa B (NF-κB) signaling pathway. ConclusionmiR-143 suppressed the osteogenic differentiation of DPSCs by blockade of NF-κB signaling pathway via targeting TNF-α.

Ergosta-7,22-diene-2β,3α,9α-triol (EGDT) from Ganoderma lucidum inhibits nasopharyngeal carcinoma cells by blocking EGFR signaling pathway

ObjectiveTo investigate the efficacy and mechanism of EGDT against NPC cell lines. MethodsMTT assay was used to assess cell proliferation inhibition of EGDT. The apoptotic induction and cell cycle arrest were detected by flow cytometry. Western blot was adopted to detect the protein levels. Quantitative Real-time PCR was used to determine the mRNA expressions. The NPC xenografts were established to evaluate the tumor growth inhibition of EGDT. Immunohistochemistry was applied to analyze the EGFR expression in the tumor tissues. ResultsEGDT showed proliferation inhibition on the NPC cell, induced G0/G1 phase arrest and cell apoptosis in vitro. EGDT decreased the protein and mRNA levels of EGFR and its downstream RAF/MEK/ERK and PI3K/AKT pathways in time- and dose-dependent manner. Furthermore, EGDT also showed a sound antitumor activity in NPC xenograft in vivo. ConclusionThe treatment of EGDT displays EGFR and its mediated downstream signaling pathway blockade through decreasing the protein and mRNA levels, suggesting a promising strategy in treating human NPC.

CNB-001, a synthetic pyrazole derivative of curcumin, suppresses lipopolysaccharide-induced nitric oxide production through the inhibition of NF-κB and p38 MAPK pathways in microglia

CNB-001, a pyrazole derivative of curcumin, has been found to exert neuroprotective and memory-enhancing effects that may be effective for the treatment of Alzheimer's disease. Since aberrant activation of microglia is involved in the pathogenesis of Alzheimer's disease, the present study was undertaken to investigate the effect of CNB-001 on microglia-mediated inflammatory responses. In primary cultured rat microglia, CNB-001 (1–10µM) suppressed the lipopolysaccharide (LPS)-induced nitric oxide (NO) production and expression of inducible NO synthase (iNOS), and the potency of CNB-001 was stronger than curcumin. CNB-001 also suppressed the LPS-induced nuclear translocation of nuclear factor κB (NF-κB), which is essential for the expression of iNOS. LPS treatment promoted phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK). CNB-001 significantly suppressed the LPS-induced phosphorylation of p38 MAPK, but not ERK and JNK. The suppressive effect of CNB-001 on NO production was mimicked by blockade of the p38 MAPK signaling pathway with SB203580. These results suggest that CNB-001 exerts anti-inflammatory effects through inhibition of NF-κB and p38 MAPK pathways in microglia.

P2X7R Blockade Prevents NLRP3 Inflammasome Activation and Pancreatic Fibrosis in a Mouse Model of Chronic Pancreatitis.

The aim of this study was to investigate the role of P2X7R (purinergic 2X7 receptor) and NLRP3 (NACHT, LRR, and PYD domains-containing protein 3) inflammasome activation in the process of pancreatic fibrosis in a mouse model of chronic pancreatitis (CP). Chronic pancreatitis was induced by repeated intraperitoneal injections of 50 μg/kg cerulein for 6 weeks in mice. P2X7R antagonist oxidized ATP (OxATP) or brilliant blue G (BBG) was administered after the last cerulein injection for 2 weeks. Pancreatic chronic inflammation and fibrosis were evaluated by histological score, Sirius red staining, and alpha-smooth muscle actin immunohistochemical staining. We further determined pancreatic P2X7R, NLRP3, and caspase-1 expressions in gene and protein levels and the pancreatic concentrations of caspase-1, interleukin 1β (IL-1β), and IL-18. The pancreatic P2X7R, NLRP3, and caspase-1 expressions in gene and protein levels and the pancreatic concentrations of caspase-1, IL-1β, and IL-18 were all reduced significantly in both the OxATP and BBG groups (P < 0.05). The pancreatic chronic inflammation and the fibrosis indices were all remarkably attenuated (P < 0.05). P2X7R antagonist OxATP and BBG significantly decreased pancreatic chronic inflammation and fibrosis in a mouse CP model and suggested that blockade of P2X7R-NLRP3 inflammasome signaling pathway may represent a novel therapeutic strategy for CP and its fibrotic process.

Targeting MAPK Signaling Pathway with Cobimetinib (GDC-0973) Enhances Anti-Leukemia Efficacy of Venetoclax (ABT-199/GDC-0199) in Acute Myeloid Leukemia Models

Abstract Despite advances in understanding of the biology of acute myeloid leukemia (AML), cure remains elusive for the majority of patients. Pro-survival molecules of BCL-2 family play critical roles in leukemia transformation and chemoresistance. The anti-leukemia potency of selective BCL-2 inhibitor venetoclax (ABT-199/GDC-0199) has been demonstrated in AML models (Pan et al. Cancer Discovery 2014). However, venetoclax is often associated with resistance due to its poor inhibition of MCL-1. RAF/MEK/ERK (MAPK) pathway is commonly activated in AML, and can stabilize anti-apoptotic MCL-1 and inactivate the pro-apoptotic BIM. In this study, we evaluated the anti-leukemia effects of concomitant BCL-2 and MAPK blockade by venetoclax in combination with MEK1/2 inhibitor GDC-0973 (cobimetinib). First, anti-leukemia activity of cobimetinib and venetoclax was examined in 18 primary AML samples with diverse genetic alterations. The combination significantly enhanced cell death, as compared to the single agent treatment (Fig 1A). Cobimetinib inhibited cell proliferation in the majority of AML cases (34.2 ± 23.7%) and the cell growth suppression was more profound in the combination group (60.2 ± 28.8%, p We next investigated signaling patterns and BCL-2 family protein expression in AML stem/progenitor cells using a 34-antibody panel for CyTOF. In AML 4400240, we identified 10 distinct subpopulations based on cell surface marker expression that were used to build the SPADE tree. BCL-2 and MCL-1 were both enriched in progenitor populations phenotypically positive for CD34, CD38, CD123 and HLA-DR (A2-5 and A9-10, Fig 1B and 1C). G-CSF-induced p-ERK and SCF-induced p-S6 signaling pathways were efficiently suppressed by cobimetinib (Fig 1D). The inhibition of p-S6 may reflect the sensitivity to cobimetinib of this sample (IC50=1.68 nM); consistent with previous study that suppression of TORC1 predicted response to MEK inhibitor (Corcoran et al. Sci Transl Med 2013). We have previously reported activity of venetoclax/cobimetinib combination in a panel of myeloid leukemia cell lines and revealed distinct response patterns to single agents and combination (Han et al. ASH 2015). Functional proteomics RPPA data indicated that p-ERK, p-S6 and p-RSK pathways were significantly down-regulated in response to the combination in cells showing synergy. Western blotting was performed to validate the RPPA data in 4 cell lines representing different response patterns. Cobimetinib inhibited p-ERK when used at high dose (1 _M) in all cell lines. In turn, inhibition of p-S6 at both ser235/236 and ser240/244 sites occurred at low dose of cobimetinib in sensitive cell lines (OCI-AML3 and MV4-11) and required high dose in resistant lines. In OCI-AML3 cells that showed synergy to combination, elevated levels of cleaved PARP was observed in the combination group, which was likely due to suppression of both BCL2:BIM and MCL-1:BIM complex, followed by release of free BIM to induce cell death. To test the efficacy in vivo, we injected NSGS mice with genetically engineered MOLM3/Luc/GFP cells. Bioluminescent imaging demonstrated significantly reduced leukemia burden in treated groups compared to controls, more prominently in the venetoclax (100 mg/kg/d) group and in venetoclax plus cobimetinib (10 mg/kg/d) co-treated mice (Fig 1E and 1F). Human CD45 engraftment and cell counts in both bone marrow and spleen demonstrated a trend towards decreased tumor burden when venetoclax was combined with cobimetinib in vivo (Fig 1G and 1H). In summary, combinatorial blockade of MAPK and BCL-2 pathways promotes cell death and suppresses proliferation in the majority of primary AML cells. The anti-leukemia efficacy of combined blockade of signaling and pro-survival pathways is associated with downregulation of MCL-1, release of pro-death BIM and suppression of p-S6. Additional novel transcriptional biomarkers of response are now being analyzed and will be presented. Combined efficacy of these agents is under clinical investigation in a Phase I trial in elderly relapsed/refractory AML (NCT02670044). Download : Download high-res image (346KB) Download : Download full-size image Disclosures Leverson: AbbVie: Employment, Other: Shareholder in AbbVie. Monique: Genentech: Employment. Phillips: AbbVie Inc.: Employment. Chen: AbbVie: Employment. Jin: AbbVie Inc.: Employment. Daver: Ariad: Research Funding; Sunesis: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Kiromic: Research Funding; BMS: Research Funding; Otsuka: Consultancy, Honoraria; Karyopharm: Honoraria, Research Funding. Jabbour: ARIAD: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Novartis: Research Funding; BMS: Consultancy. Kantarjian: Bristol-Myers Squibb: Research Funding; ARIAD: Research Funding; Amgen: Research Funding; Pfizer Inc: Research Funding; Delta-Fly Pharma: Research Funding; Novartis: Research Funding. Sampath: Genentech: Employment. Konopleva: AbbVie: Research Funding; Genentech: Research Funding.

Targeting B Cell Signaling in Chronic Lymphocytic Leukemia.

In recent years, a revolution in the management of chronic lymphocytic leukemia (CLL) has centered on the targeting of the B cell receptor (BCR) signaling pathway. Our improved understanding of the biology of cell signaling in CLL and the development of oral kinase inhibitors directed at the BCR pathway has led to the approval of two new agents and has the potential to radically change the treatment of CLL in both the relapsed/refractory and upfront settings. In this review, we will describe the underlying biology of the BCR signaling pathway. We will discuss the landmark clinical trials resulting in the approval of the Bruton tyrosine kinase (BTK) inhibitor ibrutinib and the PI3Kδ inhibitor idelalisib. We will highlight ongoing trials that are evaluating the use of combinations of these agents with standard chemotherapy. We will evaluate some of the emerging data regarding toxicity, potential off-target effects, and mechanisms of resistance to BCR signaling pathway blockade. Finally, we will highlight some of the next-generation BCR pathway inhibitors currently in development.

Cannabinoid 1 receptor blockade in the dorsal hippocampus prevents the reinstatement but not acquisition of morphine-induced conditioned place preference in rats.

The cannabinoid 1 receptors (CB1Rs) signaling is strongly linked to conditioned rewarding effects of opiates. Learned associations between environmental contexts and discrete cues and drug use play an important role in the maintenance and/or relapse of morphine addiction. Although previous studies suggest that context-dependent morphine treatment alters endocannabinoid signaling and synaptic plasticity in the hippocampus, the role of endocannabinoid in morphine conditioned place preference (CPP) and reinstatement remains unknown. In the present study, we found daily escalating doses of morphine induce significant CPP in rats. After the extinction of CPP, a priming dose of morphine was sufficient to reinstate morphine CPP and was associated with the elevated CB1R levels compared with saline control groups, suggesting upregulation of CB1R pathway in the hippocampus contribute to the reinstatement of morphine CPP. By using a pharmacological inhibitor of CB1R administered into the dorsal hippocampus, we showed that blockade of CB1R signaling did not alter the morphine CPP acquisition but inhibited the reinstatement of morphine CPP. In addition, no effects were induced upon CB1R blockade in the prefrontal cortex on reinstatement of morphine CPP. These studies reveal region-specific effects of hippocampal blockade of CB1R signaling pathway on the reinstatement of morphine CPP.

Antileukemia Efficacy and Mechanisms of Action of SL-101, a Novel Anti-CD123 Antibody Conjugate, in Acute Myeloid Leukemia.

Purpose: The persistence of leukemia stem cells (LSC)-containing cells after induction therapy may contribute to minimal residual disease (MRD) and relapse in acute myeloid leukemia (AML). We investigated the clinical relevance of CD34+CD123+ LSC-containing cells and antileukemia potency of a novel antibody conjugate SL-101 in targeting CD123+ LSCs.Experimental Methods and Results: In a retrospective study on 86 newly diagnosed AML patients, we demonstrated that a higher proportion of CD34+CD123+ LSC-containing cells in remission was associated with persistent MRD and predicted shorter relapse-free survival in patients with poor-risk cytogenetics. Using flow cytometry, we explored the potential benefit of therapeutic targeting of CD34+CD38-CD123+ cells by SL-101, a novel antibody conjugate comprising an anti-CD123 single-chain Fv fused to Pseudomonas exotoxin A The antileukemia potency of SL-101 was determined by the expression levels of CD123 antigen in a panel of AML cell lines. Colony-forming assay established that SL-101 strongly and selectively suppressed the function of leukemic progenitors while sparing normal counterparts. The internalization, protein synthesis inhibition, and flow cytometry assays revealed the mechanisms underlying the cytotoxic activities of SL-101 involved rapid and efficient internalization of antibody, sustained inhibition of protein synthesis, induction of apoptosis, and blockade of IL3-induced p-STAT5 and p-AKT signaling pathways. In a patient-derived xenograft model using NSG mice, the repopulating capacity of LSCs pretreated with SL-101 in vitro was significantly impaired.Conclusions: Our data define the mechanisms by which SL-101 targets AML and warrant further investigation of the clinical application of SL-101 and other CD123-targeting strategies in AML. Clin Cancer Res; 23(13); 3385-95. ©2017 AACR.

Sterile type 2 inflammation triggered by microparticles is abrogated by inhibition of IL33 through blockade of Bruton’s tyrosine kinase

Abstract Wear debris microparticle release associated with total joint arthroplasty may contribute to harmful inflammation, osteolysis and implant failure. We examined the role of different molecular signaling pathways in microparticle-mediated inflammation. Intraperitoneal inoculation of cobalt chrome (CoCr) in mice induced a robust innate type 2 response with increases in IL4, IL5, IL13, IL33, M2 macrophages, eosinophils and neutrophils compared to controls given vehicle only. Blockade of the SYK signaling pathway with the inhibitor BAY 61-3606 or the down stream BTK signaling pathway with Ibrutinib abrogated the CoCr-mediated innate type 2 inflammation. Further studies in CBA/Nxid mice, a genetic BTK loss of function mutant also showed decreases in type 2 inflammation, confirming a critical role for BTK in CoCr mediated sterile type 2 inflammation. Inoculation of JH−/−, B cell deficient mice, or depletion of T cells by anti-CD4 (GK1.5) antibody, had no impact on CoCr mediated type 2 inflammation. We further demonstrated that the major source of IL33 was macrophages and intra-peritoneal administration of recombinant IL33 rescued the CoCr mediated type 2 response after BTK blockade. These studies indicate that the type 2 immune response caused by solid particles is abrogated by blockade of BTK signaling pathways and that exogenous IL33 is sufficient to rescue this response. These studies elucidate the nature of wear debris-mediated type 2 sterile inflammation and provide potential targets for future therapy.

YAP1 stimulates angiogenesis and lung regeneration through the Angiopoietin‐Tie2 pathway

Angiogenesis, the formation of new blood capillaries, plays key roles in organ development and regeneration. Inhibition of angiogenesis through the blockade of angiogenic signaling pathways impairs adult lung regeneration. Previously we have reported that Wnt co‐receptor, low‐density lipoprotein receptor‐related protein 5 controls lung vascular and alveolar regeneration. The Hippo signaling transducer, Yes‐associated protein (YAP1), cooperates with Wnt‐b‐catenin signaling and controls organ size and regeneration. Here, we have demonstrated that YAP1 knockdown decreases angiogenic factor receptor Tie2 expression and inhibits endothelial cell sprouting and lung epithelial morphogenesis in vitro. YAP1 knockdown also attenuates angiogenesis and alveolar epithelial cell recruitment into the hydrogels implanted on the mouse lungs and inhibits compensatory lung growth after unilateral pneumonectomy in adult mice. These findings suggest that YAP1 plays an important role in lung vascular and alveolar regeneration and modulation of YAP1 expression in alveolar capillary endothelial cells may be a novel strategy for lung regeneration.Support or Funding InformationBoston Children's Hospital Career Development Awards

Inhibition activity of a disulfide-stabilized diabody against basic fibroblast growth factor in lung cancer.

The over-expression of basic fibroblast growth factor (bFGF) plays a crucial role in the development, invasion and metastasis of lung cancer. Therefore, neutralizing antibodies against bFGF may inhibit the growth of lung cancer. In this study, a Disulfide-stabilized diabody (ds-Diabody) against bFGF was constructed by site-directed mutation and overlap extension PCR (SOE-PCR) at the position of VH44 and VL100 in the scFv. The ds-Diabody was constructed and expressed in Pichia pastoris. We found that the ds-Diabody against bFGF could efficiently suppress the proliferation, migration and invasion of human lung cancer A549 cells in vitro. Moreover, in A549 cells, the ds-Diabody against bFGF could inhibit bFGF-induced activation of downstream signaling regulators, such as phospho-Akt and phospho-MAPK. In the nude mouse xenograft model of lung cancer, the ds-Diabody against bFGF could significantly inhibit tumor growth and decrease the densities of micro-vessels and lymphatic vessels in tumor tissue. Our data indicate that the ds-Diabody against bFGF could effectively suppress the lung cancer growth through blockade of bFGF signaling pathway and inhibition of tumor angiogenesis, which may make it a potential therapeutic candidate antibody drug for human lung cancer therapy.

Agrimonolide and Desmethylagrimonolide Induced HO-1 Expression in HepG2 Cells through Nrf2-Transduction and p38 Inactivation.

Agrimonolide and desmethylagrimonolide are the main bioactive polyphenols in agrimony with well-documented antioxidant, anti-diabetic, and anti-inflammatory potential. We report here for the first time that agrimonolide and desmethylagrimonolide stimulate the expression of phase II detoxifying enzymes through the Nrf2-dependent signaling pathway. Agrimonolide and desmethylagrimonolide also possess considerable protective activity from oxidative DNA damage. In order to explore the cytoprotective potential of agrimonolide and desmethylagrimonolide on oxidative stress in liver, we developed an oxidative stress model in HepG2 cells, and check the hypothesis whether Nrf2 pathway is involved. Western blotting and luciferase assay revealed that exposure of HepG2 cells to agrimonolide or desmethylagrimonolide leads to increased heme oxygenase-1 (HO-1) expression by activating ARE through induction of Nrf2 and suppression of Kelch-like ECH-associated protein 1 (Keap1). Moreover, agrimonolide and desmethylagrimonolide also activated ERK signaling pathways and significantly attenuated individual p38 MAPK expression, subsequently leading to Nrf2 nuclear translocation. In conclusion, our results indicated that transcriptional activation of Nrf2/ARE is critical in agrimonolide and desmethylagrimonolide-mediated HO-1 induction, which can be regulated partially by the blockade of p38 MAPK signaling pathway and inhibiting nuclear translocation of Nrf2.

CHIR99021 combined with retinoic acid promotes the differentiation of primordial germ cells from human embryonic stem cells.

Primordial germ cells (PGCs) derived from human embryonic stem cells (hESCs) represent as a desirable experimental model as well as a potential strategy for treating male infertility. Here, we developed a simple and feasible method for differentiation of PGCs from hESCs by using CHIR99021 (an inhibitor of glycogen synthase kinase 3) and retinoic acid (RA). We firstly found that the deleted in azoospermia-like (DAZL) protein can be detected in 3 d CHIR99021 plus 9 d retinoic acid treated cultures and 12 d CHIR99021 plus retinoic acid co-treated cultures, but not expressed in single CHIR99021 treated cultures, single retinoic acid treated cultures, as well as 3 d retinoic acid plus 9 d CHIR99021 treated cultures. Next, we showed that several PGCs’ markers were expressed in the 12 d CHIR99021 and retinoic acid co-treated cultures or 3 d CHIR99021 plus 9 d retinoic acid treated cultures. Moreover, meiosis was initiated in CHIR99021 and retinoic acid co-treated cultures as evidenced by a significant expression of the punctate synaptonemal complex protein 3 (SCP3). Fluorescent in situ hybridization (FISH) analysis indicated that a small percentage of putative 1N populations were formed. Mechanically, we found that β-catenin relocated into nucleus after the treatment of 3 d CHIR99021 suggesting that Wnt signaling pathway was activated. Furthermore, blockade of Wnt signaling pathway by IWR-1 can reverse CHIR99021 and retinoic acid mediated-effects. Taken together, our results indicate that CHIR99021 combined with retinoic acid can effectively differentiate hESCs into PGCs via activating Wnt signaling pathway.