scholarly journals Verbascoside down‐regulates some pro‐inflammatory signal transduction pathways by increasing the activity of tyrosine phosphatase SHP ‐1 in the U937 cell line

2015 ◽  
Vol 19 (7) ◽  
pp. 1548-1556 ◽  
Author(s):  
Mirko Pesce ◽  
Sara Franceschelli ◽  
Alessio Ferrone ◽  
Maria Anna De Lutiis ◽  
Antonia Patruno ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Cell Line ◽  
U937 Cell ◽  
Tyrosine Phosphatase ◽  
Signal Transduction Pathways

Mutations of Oncogenes Involved in Signal Transduction Pathways Are Common in AML.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2575-2575
Author(s):  
Michael C. Heinrich ◽  
Andrea Haley ◽  
Patina Harell ◽  
Ajia Town ◽  
Troy Bainbridge ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Intracellular Signaling ◽  
Somatic Mutations ◽  
Mapk Pathway ◽  
Direct Sequencing ◽  
Tyrosine Phosphatase ◽  
Signal Transduction Pathways ◽  
Gain Of Function ◽  
Kras Mutations ◽  
Pediatric Leukemia

Abstract AML is the most common type of acute leukemia in adults. Patients typically respond to initial treatment with anthracycline and cytosine arabanoside-based induction chemotherapy, but most patients ultimately relapse and die of refractory disease. Despite advances in supportive care and stem cell transplantation, the overall cure rate in adult AML has not improved significantly in the last decade. The recent success of imatinib mesylate in treating CML has fueled enthusiasm for the further development of AML therapeutic approaches that selectively target aberrant intracellular signaling. To date, inhibition of signaling pathways that are dysregulated by tumor associated somatic mutations have produced the best clinical results. The goal of our study was to more precisely define the frequency and spectrum of mutations affecting receptor tyrosine kinases (FLT3, KIT, PDGFRA, PDGFRB), MAPK pathway (NRAS, KRAS, BRAF), PI3K pathway (PIK3CA), or multiple pathways (PTPN11 tyrosine phosphatase) in adult AML. We analyzed 109 cases of adult AML for genomic DNA abnormalities involving these pathways using a combination of D-HPLC and direct sequencing. In the case of PDGFRA, we performed RT-PCR and FISH to detect FIP1L1-PDGFRA translocations. At least one gain-of-function mutation was found in 53/109 cases (48.6%) (see table) We found mutations of FLT3, KIT, NRAS, KRAS, PTPN11 or BRAF in one or more cases in our series. In contrast, none of the 109 cases had identifiable mutations of PIK3CA, PDGFRA, or PDGFRB. While mutations of NRAS or KRAS were relatively common (19 cases), mutation of BRAF was rare (1/109). In general, mutations of KIT, FLT3, NRAS and KRAS appeared to be mutually exclusive with only 1 AML case having more than one mutation of these genes (1 case with NRAS and KRAS mutations). However, mutations of PTPN11 did not appear to follow this general rule as 5 of the 9 cases with PTPN11 mutations had additional gain-of-function mutation of either FLT3 (3 cases), NRAS (1 case), or both NRAS and KRAS (1 case). We are currently in the process of correlating these mutations with other clinical parameters. We conclude that mutations involving genes directly involved in signal transduction pathways can be found in approximately 50% of cases of adult AML. These mutations represent potential therapeutic targets for treatment with an appropriate small molecular inhibitor. We hypothesize that a more comprehensive kinome wide screen of AML cases would identify an even larger percentage of cases with somatic mutations involving signal transduction pathways. Mutations of PTPN11 have been reported in non-syndromic JMML and rarely in pediatric leukemia. However, the association of PTPN11 mutations in adult AML with mutations of FLT3 or NRAS has not previously been noted. Further studies are required to fully understand the cellular consequences of dysregulated PTPN11 in myeloid leukemogenesis. Our results may also be relevant to ongoing trials of FLT3 or farnesyl transferase inhibitors in AML, as patients with a co-existent PTPN11 mutation may not respond as well to monotherapy with these agents. Mutations of Signal Transduction Pathways in 109 Cases of Adult AML Mutations Number (%) None (wild-type for all genes) 56 (51.4%) FLT3 only 18 (16.5%) FLT3+PTPN11 3 (2.8%) NRAS only 11 (10.1%) NRAS+PTPN11 2 (1.8%) NRAS+KRAS 1 (0.9%) NRAS+KRAS+PTPN11 1 (0.9%) KRAS only 5 (4.6%) KIT only 6 (5.5%) PTPN11 only 4 (3.7%) BRAF only 1 (0.9%)

scholarly journals Receptor-mediated increases in cytosolic Ca2+ in the human erythroleukaemia cell line involve pertussis toxin-sensitive and -insensitive pathways

1992 ◽  
Vol 281 (2) ◽  
pp. 301-307 ◽  
Author(s):  
I Schwaner ◽  
R Seifert ◽  
G Schultz
Keyword(s):  
Signal Transduction ◽  
Cell Line ◽  
Pertussis Toxin ◽  
Platelet Activating Factor ◽  
Model System ◽  
Cation Channels ◽  
Signal Transduction Pathways ◽  
Nucleotide Receptors ◽  
Hel Cells ◽  
Prostaglandins E1 And E2

The pluripotent human erythroleukaemia cell line, HEL, possesses erythrocytic, megakaryocytic and macrophage-like properties. With respect to signal transduction, HEL cells have been used as a model system for platelets, but little attention has been paid to their phagocytic properties. We studied the effects of various receptor agonists on the intracellular free Ca2+ concentration ([Ca2+]i) in HEL cells. Thrombin, platelet-activating factor (PAF), ATP, UTP, prostaglandins E1 and E2 (PGE1 and PGE2), the PGE2 analogue sulprostone and the stable PGI2 analogues iloprost and cicaprost increased [Ca2+]i. ADP was less effective than ATP, and UDP was unable to increase [Ca2+]i. The increases in [Ca2+]i induced by thrombin, PAF, ATP, UTP, iloprost and cicaprost were pertussis toxin-insensitive, whereas the increases induced by PGE2 and sulprostone were completely inhibited by the toxin. The increase in [Ca2+]i induced by PGE1 was partially inhibited by pertussis toxin. PGE2 did not desensitize the increase in [Ca2+]i induced by iloprost, and vice versa. PGE1 desensitized the response to PGE2 and iloprost but not vice versa. Adrenaline potentiated the iloprost- but not the PGE2-induced rise in [Ca2+]i. The phorbol ester phorbol 12-myristate 13-acetate completely blocked the rise in [Ca2+]i induced by ATP and PGE1, whereas the increases induced by thrombin and PAF were only partially inhibited. Agonists increased [Ca2+]i through release from internal stores and sustained Ca2+ influx. Thrombin stimulated Mn2+ influx, which was blocked by Ni2+. Diltiazem, isradipine, gramicidin and 1-(beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl)-1H-imidazole hydrochloride (SK&F 96365) did not affect agonist-induced rises in [Ca2+]i. HEL cells contained substantial amounts of beta-glucuronidase which, however, could not be released, and they did not aggregate or generate superoxide. Our data suggest that: (1) HEL cells possess nucleotide receptors with properties similar to those of phagocytes; (2) they possess receptors for PGE2 and PGI2, and PGE1 is an agonist at both receptors; (3) agonist-induced increases in [Ca2+]i are mediated through pertussis toxin-sensitive as well as -insensitive signal transduction pathways; and (4) agonists increase [Ca2+]i by mobilization from internal stores and influx from the extracellular space through cation channels with properties similar to those of phagocytes and platelets.

The mTOR Inhibitor Rapamycin Demonstrates Activity Against AML in Combination with Imatinib Mesylate and with 5-Azacytidine.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4318-4318 ◽  
Author(s):  
Jane L. Liesveld ◽  
Karen Rosell ◽  
Chaohui Lu ◽  
Deborah Mulford ◽  
Alison Walker
Keyword(s):  
Signal Transduction ◽  
Cell Line ◽  
Imatinib Mesylate ◽  
Cell Lines ◽  
U937 Cell ◽  
Combination Index ◽  
Mammalian Target Of Rapamycin ◽  
Serine Threonine Kinase ◽  
Signal Transduction Inhibitors ◽  
Cycle Regulation

Abstract The serine/threonine kinase mTOR (mammalian target of rapamycin) integrates pathways involved in cell cycle regulation and apoptosis and has been shown to be aberrantly activated in AML. mTOR (mammalian target of rapamycin) serine threonine kinase is involved in cell cycle regulation and apoptosis. mTOR inhibitors are a class of signal transduction inhibitors, originally developed as immunosuppressive agents, with antineoplastic activity in solid tumor models. Acute myelogenous leukemia blasts and stem cells have been reported previously to be inhibited by rapamycin, an mTOR inhibitor. As a single agent, rapamycin has minimal activity, however, suggesting that for meaningful clinical efficacy, it would require combination with other agents. We have therefore begun to examine its effects in combination with other signal transduction inhibitors and demethylating agents. Rapamycin by itself had minimal inhibitory effect on AML cell lines or primary AML samples. However, in combination with the c-kit inhibitor, imatinib mesylate, 2.5–25 uM, rapamycin demonstrated synergistic inhibition of AML cell lines such as MV411 as measured in a standard MTT assay (combination index 0.32 to 0.576 as determined with the Calcusyn program),, indicating strong synergism. In this cell line, rapamycin by itself demonstrated no significant inhibitory activity. Synergism with imatinib mesylate was also noted in the U937 and HL60 cell lines but not in the KG1a cell line. The combination of rapamycin and imatinib inhibited AKT phosphorylation to a greater extent than either agent alone in both the MV411 and U937 cell lines, but the combination did not effectively inhibit ERK phosphorylation. Inhibition of phosphorylation of p70S6 kinase by the combination of 20 uM imatinib mesylate and 80uM rapamycin did not occur to a greater extent than that seen with rapamycin alone, although phosphorylation of 4EBP1 was inhibited to a greater extent when both agents were added concurrently. When AML cell lines were exposed to 5-azacytidine alone, 1 to 16 uM, the IC50 was 4–8uM. 5-azacytidine increased apoptosis above control whereas rapamycin by itself had minimal effect on apoptosis as assessed in an Annexin V flow cytometric assay. In the U937 cell line, the combination index for the U937 cell line was 0.465 (10 uM 5-azacytidine and 100 nM rapamycin), indicating synergism. For MV411, the combination index was 0.736, for KG1a, 0.118, and for HL60, no synergism was noted. Exposure to the combination of 5-azacytidine and rapamycin resulted in greater suppression of AKT and 4EBP1 phosphorylation than did either agent singly. These data suggest that simultaneous targeting of more than one signaling pathway may improve inhibition of leukemic cell growth. Furthermore, combining signal transduction inhibitors with hypomethylating agents may also result in effective suppression of AML proliferation.

scholarly journals Surface expression of a heterologous phosphatase complements CD45 deficiency in a T cell clone.

1994 ◽  
Vol 180 (4) ◽  
pp. 1359-1366 ◽  
Author(s):  
D G Motto ◽  
M A Musci ◽  
G A Koretzky
Keyword(s):  
Signal Transduction ◽  
T Cell ◽  
Cell Line ◽  
Inositol Phosphate ◽  
Tyrosine Phosphatase ◽  
Surface Expression ◽  
Transmembrane Domains ◽  
Lymphoid Cells ◽  
Protein Tyrosine ◽  
T Cell Clone

Expression of CD45, the major transmembrane protein tyrosine phosphatase expressed on lymphoid cells, is required for optimal T cell receptor (TCR) signal transduction. We and others recently have demonstrated that surface expression of the cytoplasmic domain of CD45 in the absence of its extracellular and transmembrane domains is sufficient to restore TCR-mediated signaling events in CD45-deficient cell lines. Here we demonstrate that a single domain nonreceptor tyrosine phosphatase from yeast expressed as a chimeric protein with the extracellular and transmembrane domains of a major histocompatibility complex class I molecule also is able to restore proximal and distal TCR-mediated signal transduction events in the CD45-deficient T cell line J45.01. Ligation of the TCR on the cell line expressing the yeast phosphatase chimera results in the induction of protein tyrosine kinase activity, soluble inositol phosphate generation, and expression of the CD69 activation antigen. Furthermore, a phosphatase-inactive version of this molecule is unable to restore signal transduction, providing the first formal evidence that plasma membrane associated tyrosine phosphatase activity is required for TCR-mediated signaling.

scholarly journals Breast cancer cell line toxicity of a flavonoid isolated from Baccharis densiflora

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Wendy Soria Sotillo ◽  
Santiago Tarqui ◽  
Xiaoli Huang ◽  
Giovanna Almanza ◽  
Stina Oredsson
Keyword(s):  
Breast Cancer ◽  
Signal Transduction ◽  
Cell Line ◽  
Cell Lines ◽  
Dose Response ◽  
Transforming Growth Factor ◽  
Cell Movement ◽  
Digital Holographic Microscopy ◽  
Signal Transduction Pathways ◽  
Anti Cancer

Abstract Background Flavonoids are compounds of interest in the search for new anti-cancer therapies. We have previously isolated the methoxyflavones 5,4′-dihydroxy-6,7,8,3′-tetramethoxyflavone (8-methoxycirsilineol), 5,4′-dihydroxy-6,7,8-trimethoxyflavone (xanthomicrol), and 5,4,'3′-trihydroxy-6,7,8-trimethoxyflavone (sideritoflavone) from Baccharis densiflora. Herein, we investigate the toxicity of these methoxyflavones in human breast-derived cell line. Our main aim was to focus on the cancer stem cell (CSC) sub-population of JIMT-1 breast cancer cells. Methods Initially, dose response experiments yielding inhibitory concentration 50 (IC50) values were performed using MCF-7, HCC1937, and JIMT-1 breast cancer, and the MCF-10A normal-like breast cell lines to get an understanding of toxic ranges. Due to a clear difference in the toxicity of the flavones, only sideritoflavone was selected for further studies using the JIMT-1 cell line. Effects on the CSC sub-population was investigated using flow cytometry-based methods. A wound healing assay and digital holographic microscopy were used to investigate effects on cell movement. A reporter assay was used to study effects on signal transduction pathways and Western blot for protein expression. Results The dose response data showed that 8-methoxycirsilineol was non-toxic at concentrations below 100 μM, that the IC50 of xanthomicrol was between 50 and 100 μM, while sideritoflavone was highly toxic with a single digit μM IC50 in all cell lines. Treatment of the JIMT-1 cells with 2 μM sideritoflavone did not selectively effect the CSC sub-population. Instead, sideritoflavone treatment inhibited the proliferation of both the non-CSC and the CSC sub-populations to the same extent. The inhibition of cell proliferation resulted in an accumulation of cells in the G2 phase of the cell cycle and the treated cells showed an increased level of γ-H2A histone family member X indicating DNA double strand breaks. Analysis of the effect of sideritoflavone treatment on signal transduction pathways showed activation of the Wnt, Myc/Max, and transforming growth factor-β pathways. The level of p65/nuclear factor kappa-light-chain-enhancer of activated Β cells was increased in sideritoflavone-treated cells. Cell movement was decreased by sideritoflavone treatment. Conclusions Altogether our data show that the methoxyflavone sideritoflavone has favourable anti-cancer effects that may be exploited for development to be used in combination with CSC specific compounds.

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