2-Hydroxy-oleic acid does not activate sphingomyelin synthase activity

2-Hydroxy-oleic acid (2OHOA) is a potent anticancer drug that induces cancer cell cycle arrest and apoptosis. Previous studies have suggested that 2OHOA's anticancer effect is mediated by SMS activation in cancer cells, including A549 and U118 cells. To confirm this phenomenon, in this study, we treated both A549 and U118 cells with 2OHOA and measured SMS activity. To our surprise, we found neither 2OHOA-mediated SMS activation nor sphingomyelin accumulation in the cells. However, we noted that 2OHOA significantly reduces phosphatidylcholine in these cells. We also did not observe 2OHOA-mediated SMS activation in mouse tissue homogenates. Importantly, 2OHOA inhibited rather than activated recombinant SMS1 (rSMS1) and rSMS2 in a dose-dependent fashion. Intra-gastric treatment of C57BL/6J mice with 2OHOA for 10 days had no effects on liver and small intestine SMS activities and plasma sphingomyelin levels. The treatment inhibited lysophosphatidylcholine acyltransferase (LPCAT) activity, consistent with the aforementioned reduction in plasma phosphatidylcholine. Because total cellular phosphatidylcholine is used as a predictive biomarker for monitoring tumor responses, the previously reported 2OHOA-mediated cancer suppression could be related to this phosphatidylcholine reduction, which may influence cell membrane structure and properties. We conclude that 2OHOA is not a SMS activator and that its anticancer property may be related to an effect on phosphatidylcholine metabolism.

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Early changes in phosphatidylcholine metabolism in human acute promyelocytic leukemia cells stimulated to differentiate by phorbol ester

Blood ◽

10.1182/blood.v58.2.237.bloodjournal582237 ◽

1981 ◽

Vol 58 (2) ◽

pp. 237-243

Author(s):

PA Cassileth ◽

D Suholet ◽

RA Cooper

Keyword(s):

Acute Promyelocytic Leukemia ◽

Phorbol Ester ◽

Leukemia Cell ◽

Promyelocytic Leukemia ◽

Leukemia Cell Line ◽

Dose Dependent Fashion ◽

Dose Dependent ◽

Human Acute Promyelocytic Leukemia ◽

Phosphatidylcholine Synthesis ◽

Phosphatidylcholine Metabolism

The HL-60 leukemia cell line derived from a human acute promyelocytic leukemia is stimulated to differentiate into macrophages within 24–28 hr after exposure to the phorbol ester, 12-O-tetradecanoylphorbol-13- acetate (TPA). We studied early alterations (within 90 min of exposure to TPA) in phosphatidylcholine metabolism in HL-60 cells and found that phosphatidylcholine synthesis by methylation is phosphatidylethanolamine was inhibited in a dose-dependent fashion. In contrast, synthesis of phosphatidylcholine from endogenous choline was enhanced and correlated inversely with the degree of inhibition of the methylation pathway. Phorbol ester congeners of TPA caused similar alterations in phosphatidylcholine metabolism in direct relationship to their capacity to induce differentiation in HL-60 cells. Perturbation of phosphatidylcholine metabolism is an early membrane even in TPA- induced HL-60 cell differentiation.

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Early changes in phosphatidylcholine metabolism in human acute promyelocytic leukemia cells stimulated to differentiate by phorbol ester

Blood ◽

10.1182/blood.v58.2.237.237 ◽

1981 ◽

Vol 58 (2) ◽

pp. 237-243 ◽

Cited By ~ 24

Author(s):

PA Cassileth ◽

D Suholet ◽

RA Cooper

Keyword(s):

Acute Promyelocytic Leukemia ◽

Phorbol Ester ◽

Leukemia Cell ◽

Promyelocytic Leukemia ◽

Leukemia Cell Line ◽

Dose Dependent Fashion ◽

Dose Dependent ◽

Human Acute Promyelocytic Leukemia ◽

Phosphatidylcholine Synthesis ◽

Phosphatidylcholine Metabolism

Abstract The HL-60 leukemia cell line derived from a human acute promyelocytic leukemia is stimulated to differentiate into macrophages within 24–28 hr after exposure to the phorbol ester, 12-O-tetradecanoylphorbol-13- acetate (TPA). We studied early alterations (within 90 min of exposure to TPA) in phosphatidylcholine metabolism in HL-60 cells and found that phosphatidylcholine synthesis by methylation is phosphatidylethanolamine was inhibited in a dose-dependent fashion. In contrast, synthesis of phosphatidylcholine from endogenous choline was enhanced and correlated inversely with the degree of inhibition of the methylation pathway. Phorbol ester congeners of TPA caused similar alterations in phosphatidylcholine metabolism in direct relationship to their capacity to induce differentiation in HL-60 cells. Perturbation of phosphatidylcholine metabolism is an early membrane even in TPA- induced HL-60 cell differentiation.

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Induction of Cell Cycle Arrest and Apoptosis by Dephosphorylation of ERK, Akt, and Bcl-2 and Phosphorylation of JNK by LY293111 in Human Anaplastic Large Cell Lymphoma (ALCL).

Blood ◽

10.1182/blood.v104.11.3396.3396 ◽

2004 ◽

Vol 104 (11) ◽

pp. 3396-3396

Author(s):

Weiguo Zhang ◽

Marina Konopleva ◽

Teresa McQueen ◽

Wendy Schober ◽

Michael Andreeff

Keyword(s):

Cell Cycle ◽

Anaplastic Large Cell Lymphoma ◽

Cell Lymphoma ◽

Large Cell ◽

Leukotriene B4 ◽

Caspase 9 ◽

Cycle Arrest ◽

Dose Dependent Fashion ◽

Large Cell Lymphoma ◽

Dose Dependent

Abstract The prognosis of patients with anaplastic large cell lymphoma (ALCL) treated with standard chemotherapy remains poor. Leukotriene B4 (LTB4) receptor has been reported to exhibit a growth-promoting activity in lymphoma, since it augments DNA synthesis and increases cell proliferation of lymphocytes. LY293111 (2-[2-propyl-3-[3-[2-ethyl-4-(4-fluorophenyl)-5-hydroxyphenoxy]-propoxy]-phenoxy] benzoic acid sodium salt) is a Leukotriene B4 receptor antagonist, which was found to be safe and tolerable in Phase I clinical trials. LY293111 inhibits pancreatic cancer cell growth, induces apoptosis, and reduces growth of colon cancer in vivo. In the present study, we investigated the potential therapeutic effects and mechanisms of action of LY293111 in an ALCL cell line. We utilized the Sup/M2 cell line derived from human anaplastic large cell lymphoma as a model. Dose-response studies demonstrated that the IC50 of LY293111 was 4μM after 5 days of treatment. LY293111 caused retardation of Sup/M2 cell entry into S phase in a dose-dependent fashion as measured by BrdU/propidium iodide flow cytometry. LY293111 at 2.5μM induced complete G1-S cell cycle arrest in cells synchronized by serum starvation. LY293111 upregulated p21 and p27 protein expression and reduced cyclin E mRNA and protein. Pre-treatment with LY293111 for 4 hours resulted in profound inhibition of serum-induced phosphorylation of ERK1/2, Akt, and Bcl-2. Concomitantly, phosphorylation of stress-activated kinase JNK dramatically increased following LY293111 treatment. LY293111 induced pronounced apoptosis of Sup/M2 cells and caspase inhibition by Benzyloxycarbonyl -Val-Ala-Asp (OMe) fluoromethylketone (Z-VAD.FMK) abrogated this effect. LY293111 induced cleavage of the caspase-9, -3, PARP and XIAP, but had no effect on caspase-8, suggesting activation of the intrinsic apoptotic pathway. Accordingly, early loss of mitochondrial membrane potential was observed in a dose-dependent fashion. At 72 hrs, LY293111 decreased Bcl-2 expression levels. These findings provide the first evidence that LY293111 inhibits ALCL proliferation by arresting cells in G1 phase of the cell cycle, as a result of cyclin E downregulation and induction of cell-cycle inhibitory proteins p21 and p27. LY293111 induces apoptosis in Sup/M2 lymphoma cells, with activation of the mitochondrial apoptosis pathway, including cleavage of caspase 9, caspase 3, PARP, XIAP, and Bcl-2. Furthermore, LY293111 treatment markedly shifts signaling toward the JNK stress-related pathway and away from cytoprotective MEK/ERK and AKT signaling. These results suggest that LY293111 may have a utility in the management of aggressive non-Hodgkin’s lymphomas.

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Plasminogen Interactions with Immobilized Fibrinogen

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647121 ◽

1989 ◽

Vol 62 (04) ◽

pp. 1078-1082 ◽

Cited By ~ 5

Author(s):

Burt Adelman ◽

Patricia Ouynn

Keyword(s):

Immunosorbent Assay ◽

Aminocaproic Acid ◽

Enzyme Linked Immunosorbent Assay ◽

Binding Regions ◽

Dose Dependent Fashion ◽

Epsilon Aminocaproic Acid ◽

Dose Dependent

SummaryThis report describes the binding of plasminogen to fibrinogen adsorbed onto polystyrene wells. Binding was determined by enzyme linked immunosorbent assay. Both glu- and lys-plasminogen bound to immobilized fibrinogen in a dose-dependent fashion. However, more lys- than glu-plasminogen bound when equal concentrations of either were added to immobilized fibrinogen. Plasminogen binding was inhibited by epsilon aminocaproic acid indicating that binding was mediated via lysine-binding regions of plasminogen. Soluble fibrinogen added in excess of immobilized fibrinogen did not compete for plasminogen binding but fibrinogen fragments produced by plasmin digestion of fibrinogen did. Treatment of immobilized fibrinogen with thrombin caused a small but significant (p <0.01) increase in plasminogen binding. These studies demonstrate that immobilized fibrinogen binds both glu- and lys-plasminogen and that binding is mediated via lysine-binding regions. These interactions may facilitate plasminogen binding to fibrinogen adsorbed on to surfaces and to cells such as platelets which bind fibrinogen.

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Soluble Thrombomodulin Purified from Human Urine Exhibits a Potent Anticoagulant Effect In Vitro and In Vivo

Thrombosis and Haemostasis ◽

10.1055/s-0038-1653872 ◽

1995 ◽

Vol 73 (05) ◽

pp. 805-811 ◽

Cited By ~ 12

Author(s):

Yasuo Takahashi ◽

Yoshitaka Hosaka ◽

Hiromi Niina ◽

Katsuaki Nagasawa ◽

Masaaki Naotsuka ◽

...

Keyword(s):

Human Urine ◽

Specific Activity ◽

Anticoagulant Activity ◽

Rabbit Lung ◽

Soluble Thrombomodulin ◽

Molecular Weights ◽

Dose Dependent Fashion ◽

Dose Dependent

SummaryWe examined the anticoagulant activity of two major molecules of soluble thrombomodulin purified from human urine. The apparent molecular weights of these urinary thrombomodulins (UTMs) were 72,000 and 79,000, respectively. Both UTMs showed more potent cofactor activity for protein C activation [specific activity >5,000 thrombomodulin units (TMU)/mg] than human placental thrombomodulin (2,180 TMU/mg) and rabbit lung thrombomodulin (1,980 TMU/mg). The UTMs prolonged thrombin-induced fibrinogen clotting time (>1 TMU/ml), APTT (>5 TMU/ml), TT (>5 TMU/ml) and PT (>40 TMU/ml) in a dose-dependent fashion. These effects appeared in the concentration range of soluble thrombomodulins present in human plasma and urine. In the rat DIC model induced by thromboplastin, administration of UTMs by infusion (300-3,000 TMU/kg) restored the hematological abnormalities derived from DIC in a dose-dependent fashion. These results demonstrate that UTMs exhibit potent anticoagulant and antithrombotic activities, and could play a physiologically important role in microcirculation.

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Faculty Opinions recommendation of CTLA4 blockade expands FoxP3+ regulatory and activated effector CD4+ T cells in a dose-dependent fashion.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1120832.577093 ◽

2008 ◽

Author(s):

Andrew Weinberg

Keyword(s):

T Cells ◽

Cd4 T Cells ◽

Ctla4 Blockade ◽

Dose Dependent Fashion ◽

Dose Dependent

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IMMU-09. CONCURRENT DEXAMETHASONE LIMITS THE CLINICAL BENEFIT OF IMMUNE CHECKPOINT BLOCKADE IN GLIOBLASTOMA

Neuro-Oncology ◽

10.1093/neuonc/noaa215.440 ◽

2020 ◽

Vol 22 (Supplement_2) ◽

pp. ii106-ii106

Author(s):

Bryan Iorgulescu ◽

Prafulla Gokhale ◽

Maria Speranza ◽

Benjamin Eschle ◽

Michael Poitras ◽

...

Keyword(s):

Prognostic Factors ◽

Immune Checkpoint ◽

Nk Cell ◽

Immune Checkpoint Blockade ◽

Checkpoint Blockade ◽

Innate Immune Responses ◽

Dose Dependent Fashion ◽

Dexamethasone Therapy ◽

Clinical Correlate ◽

Dose Dependent

Abstract BACKGROUND Dexamethasone, a uniquely potent corticosteroid, is frequently administered to brain tumor patients to decrease tumor-associated edema, but limited data exist describing how dexamethasone affects the immune system systemically and intratumorally in glioblastoma patients – particularly in the context of immunotherapy. METHODS We evaluated the dose-dependent effects of dexamethasone when administered with anti-PD-1 and/or radiotherapy in immunocompetent C57BL/6 mice with syngeneic GL261 or CT-2A glioblastoma tumors, including analyses of intracranial tumors, draining lymph nodes, and spleen. Clinically, the effect of dexamethasone on survival was additionally evaluated in 181 consecutive IDH-wildtype glioblastoma patients treated with anti-PD-(L)1, with adjustment for relevant prognostic factors. RESULTS Despite the inherent responsiveness of GL261 to immune checkpoint blockade, concurrent dexamethasone administration with anti-PD-1 therapy decreased survival in a dose-dependent fashion and decreased survival following anti-PD-1 plus radiotherapy in both GL261 and immunoresistant CT-2A models. Dexamethasone quantitatively decreased T lymphocytes by reducing the proliferation while increasing apoptosis. Dexamethasone also decreased lymphocyte functional capacity. Myeloid and NK cell populations were also generally reduced. Thus, dexamethasone negatively affects both the adaptive and innate immune responses. As a clinical correlate, a retrospective analysis of 181 consecutive IDH-wildtype glioblastoma patients treated with PD-(L)1 blockade revealed worse survival among those on baseline dexamethasone. Upon multivariable adjustment with relevant prognostic factors, baseline dexamethasone use – regardless of dose – was the strongest predictor of poor survival (reference no dexamethasone; < 2mg HR 2.28, 95%CI=1.41–3.68, p=0.001; ≥2mg HR 1.97, 95%CI=1.27–3.07, p=0.003). CONCLUSIONS Our preclinical and clinical data indicate that concurrent dexamethasone therapy may be detrimental to immunotherapeutic approaches for glioblastoma patients. Our preclinical analyses also suggest that dexamethasone’s detrimental effects are dose-dependent, suggesting that the lowest possible dose should be used for patients when dexamethasone use is unavoidable. Careful evaluation of dexamethasone use is warranted for neuro-oncology patients undergoing immunotherapy clinical trials.

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Linkage of [Ca2+]i in single isolated D cells to somatostatin secretion induced by cholecystokinin

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1996.270.6.g897 ◽

1996 ◽

Vol 270 (6) ◽

pp. G897-G901 ◽

Cited By ~ 3

Author(s):

J. DelValle ◽

J. Wakasugi ◽

H. Takeda ◽

T. Yamada

Keyword(s):

Channel Blocker ◽

Gastric Fundus ◽

Initial Transient ◽

Somatostatin Secretion ◽

Phospholipid Signaling ◽

Dose Dependent Fashion ◽

Direct Linkage ◽

D Cells ◽

Transient Elevation ◽

Dose Dependent

The Ca2+/inositol phospholipid signaling cascade has been implicated in the mechanism by which cholecystokinin (CCK) stimulates gastric somatostatin release, but a direct linkage between intracellular events in gastric D cells and somatostatin secretion has not been established. To address this problem we developed a method for correlating somatostatin release with the measurement of intracellular Ca2+ concentration ([Ca2+]i) in isolated D cells. Resting [Ca2+]i in single D cells was 100 +/- 5.7 nM (means +/- SE, n = 41), and CCK induced a rise in [Ca2+]i in a dose-dependent fashion, producing a maximal stimulatory effect (243 +/- 15% of control, n = 12) at a peptide concentration of 2 x 10(-8) M. The CCK-mediated increase in [Ca2+]i was biphasic, with a rapid, initial transient elevation followed by a sustained plateau. The rise in [Ca2+]i was accompanied by a concomitant increase in release of somatostatin-like immunoreactivity (SLI). Removal of extracellular Ca2+ had no effect on the initial transient elevation in [Ca2+]i induced by CCK but abolished both the sustained plateau in [Ca2+]i and the release of SLI. The selective CCK antagonist L-364, 718 (10(-7) M) inhibited the effects of CCK on both [Ca2+]i and SLI release. The nonspecific Ca2+ channel blocker NiCl2 (10(-3) M) and the L-type Ca2+ channel blocker nifedipine inhibited the sustained rise in [Ca2+]i and the release of SLI but left the initial transient increase in [Ca2+]i unaltered. These results indicate that CCK-stimulated release of SLI from D cells in the gastric fundus is linked to influx of extracellular Ca2+ via L-type Ca2+ channels.

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Extract of Pogostemon cablin Possesses Potent Anticancer Activity against Colorectal Cancer Cells In Vitro and In Vivo

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2020/9758156 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

Ju-Huei Chien ◽

Shan-Chih Lee ◽

Kai-Fu Chang ◽

Xiao-Fan Huang ◽

Yi-Ting Chen ◽

...

Keyword(s):

Colorectal Cancer ◽

Cell Apoptosis ◽

Cycle Arrest ◽

Anticancer Effects ◽

Pogostemon Cablin ◽

Colorectal Cancer Cells ◽

Potential Applicability ◽

Cancer Suppression

Pogostemon cablin (PCa), an herb used in traditional Chinese medicine, is routinely used in the amelioration of different types of gastrointestinal discomfort. However, the mechanisms underlying the cancer suppression activity of PCa in colorectal cancer (CRC) cells have yet to be clarified. The aim of this study was to investigate the anticancer effects of PCa, specifically the induction of apoptosis in CRC cells. The growth inhibition curve of CRC cells following exposure to PCa was detected by an MTT assay. Moreover, PCa combined with 5-FU revealed a synergic effect of decreased cell viability. PCa inhibited cell proliferation and induced cell cycle arrest at the G0/G1 phase and cell apoptosis through regulation of associated protein expression. An in vivo study showed that PCa suppressed the growth of CRC via induction of cell apoptosis with no significant change in body weight or organ histology. Our results demonstrated that PCa inhibits the growth of CRC cells and induces apoptosis in vitro and in vivo, which suggests the potential applicability of PCa as an anticancer agent.

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11-Dehydrocorticosterone, a glucocorticoid metabolite, inhibits aldosterone action in toad bladder

AJP Renal Physiology ◽

10.1152/ajprenal.1991.261.5.f873 ◽

1991 ◽

Vol 261 (5) ◽

pp. F873-F879 ◽

Cited By ~ 3

Author(s):

A. S. Brem ◽

K. L. Matheson ◽

J. L. Barnes ◽

D. J. Morris

Keyword(s):

Sodium Transport ◽

Cell Layer ◽

Short Circuit ◽

Short Circuit Current ◽

Hydroxysteroid Dehydrogenase ◽

Toad Bladder ◽

Compound A ◽

Dose Dependent Fashion ◽

Epithelial Cell Layer ◽

Dose Dependent

The enzyme 11 beta-hydroxysteroid dehydrogenase (11 beta-OHSD) metabolizes glucocorticoid hormones and diminishes their ability to induce sodium transport. In these studies, we determined the location of this enzyme in toad bladder and assessed the biological role for its 11-dehydro end product. Employing a polyclonal antibody directed toward 11 beta-OHSD and immunofluorescence techniques, we located the enzyme in the epithelial cell layer of the toad bladder. Although corticosterone (10(-7) M) can partially suppress aldosterone (10(-7) M)-stimulated short-circuit current (SCC), a clear excess of corticosterone (10(-6) M) did not inhibit the aldosterone-induced induced (10(-8) M) rise in SCC (n = 6). The 11-dehydro product of corticosterone, 11-dehydrocorticosterone (compound A) added to the serosal bath suppressed aldosterone (10(-8) M) peak SCC (360 min) in a dose-dependent fashion reaching 46 +/- 5% of control values at 10(-5) M (n = 6; P less than 0.001). Compound A (10(-5) M) in the mucosal bath also was capable of partially inhibiting the peak aldosterone rise in SCC to 63 +/- 7% of control values with aldosterone at 10(-8) M (n = 6; P less than 0.01) and to 64 +/- 10% of control values with aldosterone at 10(-7) M (n = 9; P less than 0.01). Compound A alone at 10(-5) M did not have any effect on SCC. Isolated toad bladders were not able to transform compound A (at 10(-8) and 10(-5) M) back to corticosterone. Thus the 11-dehydro end product of 11 beta-OHSD (compound A) may play a biologic role by regulating a component of mineralocorticoid-induced sodium transport.

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