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Clinical Cancer Research : An Official... Mar 2018Chemoresistance in triple-negative breast cancer (TNBC) is associated with the activation of a survival mechanism orchestrated by the endoplasmic reticulum (EnR) stress...
Chemoresistance in triple-negative breast cancer (TNBC) is associated with the activation of a survival mechanism orchestrated by the endoplasmic reticulum (EnR) stress response and by inducible nitric oxide synthase (iNOS). Our aim was to determine the effects of pharmacologic NOS inhibition on TNBC. TNBC cell lines, SUM-159PT, MDA-MB-436, and MDA-MB-468, were treated with docetaxel and NOS inhibitor (L-NMMA) for 24, 48, and 72 hours. Apoptosis was assessed by flow cytometry using Annexin-V and propidium iodide. Western blot was used to assess ER stress and apoptosis, and rtPCR was used to evaluate s-XBP1. TNBC patient-derived xenografts (PDX) were treated either with vehicle, docetaxel, or combination therapy (NOS inhibition + docetaxel). Mouse weight and tumor volumes were recorded twice weekly. Docetaxel concentration was determined using mass spectrometry. To quantify proliferation and apoptosis, PDX tumor samples were stained using Ki67 and TUNEL assay. L-NMMA ameliorated the iNOS upregulation associated with docetaxel. Apoptosis increased when TNBC cells were treated with combination therapy. In TNBC PDXs, combination therapy significantly reduced tumor volume growth and increased survival proportions. In the BCM-5998 PDX model, intratumoral docetaxel concentration was higher in mice receiving combination therapy. Coupling docetaxel with NOS inhibition increased EnR-stress response via coactivation of ATF4 and CHOP, which triggered the pASK1/JNK proapoptotic pathway, promoting cleavage of caspases 3 and 9. iNOS is a critical target for docetaxel resistance in TNBC. Pharmacologic inhibition of NOS enhanced chemotherapy response in TNBC PDX models. Combination therapy may improve prognosis and prevent relapse in TNBC patients who have failed conventional chemotherapy. .
Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Line, Tumor; Docetaxel; Drug Synergism; Female; Humans; JNK Mitogen-Activated Protein Kinases; MAP Kinase Kinase Kinase 5; MAP Kinase Signaling System; Mice; Mice, SCID; Nitric Oxide Synthase Type II; Triple Negative Breast Neoplasms; Xenograft Model Antitumor Assays; omega-N-Methylarginine
PubMed: 29301832
DOI: 10.1158/1078-0432.CCR-17-1437 -
American Journal of Physiology. Heart... Jan 2006Earlier we reported that dietary folate depletion causes hyperhomocysteinemia (HHcy) and arterial dysfunction in rats (Symons JD, Mullick AE, Ensunsa JL, Ma AA, and...
Earlier we reported that dietary folate depletion causes hyperhomocysteinemia (HHcy) and arterial dysfunction in rats (Symons JD, Mullick AE, Ensunsa JL, Ma AA, and Rutledge JC. Arterioscler Thromb Vasc Biol 22: 772-780, 2002). Both HHcy and low folate (LF) are risk factors for cardiovascular disease. Therefore, the dysfunction we observed could have resulted from HHcy, LF, and/or their combination (HHcy + LF). We tested the hypothesis that HHcy-induced vascular dysfunction is more severe in the presence of LF. Four groups of rats consumed diets for approximately 10 wk that produced plasma homocysteine (microM) and liver folate (microg folate/g liver) concentrations, respectively, of 7 +/- 1 and 15 +/- 1 (Control; Con; n = 16), 17 +/- 2 and 15 +/- 2 (HHcy; n = 17), 10 +/- 1 and 8 +/- 1 (LF; n = 14), and 21 +/- 2 and 8 +/- 1 (HHcy + LF; n = 18). We observed that maximal ACh-evoked vasorelaxation was greatest in aortas and mesenteric arteries from Con rats vs. all groups. While the extent of dysfunction was similar between LF and HHcy animals, it was less severe compared with arteries from HHcy + LF rats. Maximal ACh-evoked vasorelaxation in coronary arteries was not different between Con and LF rats, but both were greater than HHcy + LF animals. In segments of aortas, 1) ACh-evoked vasorelaxation was similar among groups after incubation with the nonenzymatic intracellular O2(-) scavenger Tiron, 2) vascular O2(-) estimated using dihydroethidium staining was greatest in HHcy + LF vs. all groups, and 3) tension development in response to nitric oxide (NO) synthase inhibition was greatest in Con vs. all other groups. We conclude that HHcy + LF evokes greater dysfunction than either HHcy alone (aortas, mesentery) or LF alone (aortas, mesentery, coronary), likely by producing more O2(-) within the vasculature and thereby reducing NO bioavailability.
Topics: Acetylcholine; Animals; Diet; Endothelium, Vascular; Folic Acid Deficiency; Hyperhomocysteinemia; Male; Methionine; Nitric Oxide; Nitroprusside; Oxygen; Rats; Vasodilation; omega-N-Methylarginine
PubMed: 16143648
DOI: 10.1152/ajpheart.00765.2005 -
Redox Biology Sep 2019L-N-Nitro arginine methyl ester (L-NAME) has been widely applied for several decades in both basic and clinical research as an antagonist of nitric oxide synthase (NOS)....
L-N-Nitro arginine methyl ester (L-NAME) has been widely applied for several decades in both basic and clinical research as an antagonist of nitric oxide synthase (NOS). Herein, we show that L-NAME slowly releases NO from its guanidino nitro group. Daily pretreatment of rats with L-NAME potentiated mesenteric vasodilation induced by nitrodilators such as nitroglycerin, but not by NO. Release of NO also occurred with the NOS-inactive enantiomer D-NAME, but not with L-arginine or another NOS inhibitor L-NMMA, consistent with the presence or absence of a nitro group in their structure and their nitrodilator-potentiating effects. Metabolic conversion of the nitro group to NO-related breakdown products was confirmed using isotopically-labeled L-NAME. Consistent with Fenton chemistry, transition metals and reactive oxygen species accelerated the release of NO from L-NAME. Both NO production from L-NAME and its nitrodilator-potentiating effects were augmented under inflammation. NO release by L-NAME can confound its intended NOS-inhibiting effects, possibly by contributing to a putative intracellular NO store in the vasculature.
Topics: Animals; Arginine; Enzyme Inhibitors; Female; Mesenteric Arteries; Mice; Myography; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Synthase; Nitroglycerin; RAW 264.7 Cells; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Sheep; Stereoisomerism; Vasodilation; Vasodilator Agents; omega-N-Methylarginine
PubMed: 31200239
DOI: 10.1016/j.redox.2019.101238 -
Tissue & Cell Dec 2021Puerarin regulates the osteoblast differentiation of umbilical cord mesenchymal stem cells. This study, hereby, explored the effects of puerarin on the osteogenic...
Puerarin regulates the osteoblast differentiation of umbilical cord mesenchymal stem cells. This study, hereby, explored the effects of puerarin on the osteogenic differentiation of dental follicle cells (DFCs) for the first time. Rat DFCs (rDFCs) were isolated and identified. After the rDFCs were treated by Puerarin and cultured in osteogenic induction medium, the viability, osteogenic differentiation, and the activities of alkaline phosphatase (ALP) and nitric oxide (NO) were detected. Besides, the secretion of cyclic guanosine monophosphate (cGMP) and expressions of collagen I, osteocalcin (OC), osteopontin (OPN), runt-related transcription factor 2 (RUNX2), soluble guanylate cyclase (SGC), and protein kinase G 1 (PKG-1) were further determined or quantified. Puerarin enhanced the viability and osteogenic differentiation, and increased the activities of ALP, NO, and cGMP and the expressions of Collagen I, OC, OPN, RUNX2, SGC, and PKG-1 in rDFCs. After the co-treatment with puerarin and L-NMMA (NO synthase inhibitor), the promotive effects of Puerarin on cell viability, osteogenic differentiation, and the expressions of collagen I, OC, OPN, RUNX2, SGC, and PKG-1 in rDFCs were reversed by L-NMMA. Puerarin boosted the osteogenic differentiation of rDFCs by activating the NO pathway.
Topics: Alkaline Phosphatase; Animals; Animals, Newborn; Cell Differentiation; Cell Survival; Cells, Cultured; Collagen Type I; Core Binding Factor Alpha 1 Subunit; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Dental Sac; Guanylate Cyclase; Isoflavones; Nitric Oxide; Osteocalcin; Osteogenesis; Osteopontin; Rats, Sprague-Dawley; Solubility; omega-N-Methylarginine; Rats
PubMed: 34371290
DOI: 10.1016/j.tice.2021.101601 -
American Journal of Physiology. Heart... Apr 2012The purpose of this study was to determine if tonic restrain of blood pressure by nitric oxide (NO) is impaired early in the development of hypertension. Impaired NO...
The purpose of this study was to determine if tonic restrain of blood pressure by nitric oxide (NO) is impaired early in the development of hypertension. Impaired NO function is thought to contribute to hypertension, but it is not clear if this is explained by direct effects of NO on vascular tone or indirect modulation of sympathetic activity. We determined the blood pressure effect of NO synthase inhibition with N(ω)-monomethyl-l-arginine (L-NMMA) during autonomic blockade with trimethaphan to eliminate baroreflex buffering and NO modulation of autonomic tone. In this setting, impaired NO modulation of vascular tone would be reflected as a blunted pressor response to L-NMMA. We enrolled a total of 66 subjects (39 ± 1.3 yr old, 30 females), 20 normotensives, 20 prehypertensives (blood pressure between 120/80 and 140/90 mmHg), 17 hypertensives, and 9 smokers (included as "positive" controls of impaired NO function). Trimethaphan normalized blood pressure in hypertensives, suggesting increased sympathetic tone contributing to hypertension. In contrast, L-NMMA produced similar increases in systolic blood pressure in normal, prehypertensive, and hypertensive subjects (31 ± 2, 32 ± 2, and 30 ± 3 mmHg, respectively), whereas the response of smokers was blunted (16 ± 5 mmHg, P = 0.012). Our results suggest that sympathetic activity plays a role in hypertension. NO tonically restrains blood pressure by ∼30 mmHg, but we found no evidence of impaired modulation by NO of vascular tone contributing to the early development of hypertension. If NO deficiency contributes to hypertension, it is likely to be through its modulation of the autonomic nervous system, which was excluded in this study.
Topics: Adolescent; Adult; Aging; Baroreflex; Blood Pressure; Enzyme Inhibitors; Female; Heart Rate; Humans; Hypertension; Male; Middle Aged; Muscle Tonus; Muscle, Smooth, Vascular; Nicotinic Antagonists; Nitric Oxide; Nitric Oxide Synthase Type III; Receptors, Nicotinic; Smoking; Sympathetic Nervous System; Trimethaphan; Young Adult; omega-N-Methylarginine
PubMed: 22287587
DOI: 10.1152/ajpheart.01020.2011 -
Journal of Vascular Research 2014Bradykinin (BK) stimulates tissue plasminogen activator (t-PA) release from human endothelium. Although BK stimulates both nitric oxide and endothelium-derived... (Clinical Trial)
Clinical Trial
AIMS
Bradykinin (BK) stimulates tissue plasminogen activator (t-PA) release from human endothelium. Although BK stimulates both nitric oxide and endothelium-derived hyperpolarizing factor (EDHF) release, the role of EDHF in t-PA release remains unexplored. This study sought to determine the mechanisms of BK-stimulated t-PA release in the forearm vasculature of healthy human subjects.
METHODS
In 33 healthy subjects (age 40.3 ± 1.9 years), forearm blood flow (FBF) and t-PA release were measured at rest and after intra-arterial infusions of BK (400 ng/min) and sodium nitroprusside (3.2 mg/min). Measurements were repeated after intra-arterial infusion of tetraethylammonium chloride (TEA; 1 µmol/min), fluconazole (0.4 µmol·min(-1)·l(-1)), and N(G)-monomethyl-L-arginine (L-NMMA, 8 µmol/min) to block nitric oxide, and their combination in separate studies.
RESULTS
BK significantly increased net t-PA release across the forearm (p < 0.0001). Fluconazole attenuated both BK-mediated vasodilation (-23.3 ± 2.7% FBF, p < 0.0001) and t-PA release (from 50.9 ± 9.0 to 21.3 ± 8.9 ng/min/100 ml, p = 0.02). TEA attenuated FBF (-14.7 ± 3.2%, p = 0.002) and abolished BK-stimulated t-PA release (from 22.9 ± 5.7 to -0.8 ± 3.6 ng/min/100 ml, p = 0.0002). L-NMMA attenuated FBF (p < 0.0001), but did not inhibit BK-induced t-PA release (nonsignificant).
CONCLUSION
BK-stimulated t-PA release is partly due to cytochrome P450-derived epoxides and is inhibited by K(+)Ca channel blockade. Thus, BK stimulates both EDHF-dependent vasodilation and t-PA release.
Topics: Adult; Biological Factors; Bradykinin; Cytochrome P-450 Enzyme System; Female; Fluconazole; Forearm; Humans; Male; Middle Aged; Nitroprusside; Potassium Channels, Calcium-Activated; Regional Blood Flow; Tetraethylammonium; Tissue Plasminogen Activator; Vasodilation; omega-N-Methylarginine
PubMed: 24925526
DOI: 10.1159/000362666 -
Journal of Basic and Clinical... 2013Nerve growth factor (NGF) is a neurotrophin that supports the survival and differentiation of sympathetic neurons, and its increased expression after myocardial infarct...
BACKGROUND
Nerve growth factor (NGF) is a neurotrophin that supports the survival and differentiation of sympathetic neurons, and its increased expression after myocardial infarct was correlated with cardiac sympathetic hyperinnervation and arrhythmias. However, it is unclear whether NGF protects the heart during infarct. In this study, we sought to address this issue in rat heart exposed to ischemia/reperfusion injury (IRI).
METHODS
NGF was administered intravenously (IV), 15 min before ischemia, at different concentrations in the absence or presence of inhibitors of phosphatidylinositol-3 kinase (PI3K) or nitric oxide synthase (NOS) in different groups of rats (n=6) with left coronary occlusion for 30 min followed by 120-min reperfusion. The area at risk and infarct to risk ratios were determined from sections stained with 1% 2,3,5-triphenylterazolium chloride.
RESULTS
NGF treatment at doses of 0.015-15 μg/kg, with an optimal dose of 0.15 μg/kg given IV before ischemia, reduced the infarct size from about 60% at the area of risk to about 25%, indicating cardioprotection by about 60%. The infarct-sparing effects of NGF were partially abolished by the inhibition of PI3K and NOS using wortmannin and N(G)-monomethyl-l-arginine, respectively.
CONCLUSIONS
We have demonstrated for the first time that NGF attenuates myocardial infarct damage in an in vivo rat model of myocardial regional IRI. This cardioprotective effect is proposed to be related to the activities of PI3K and NOS. This suggests that NGF has a potential therapeutic role in the treatment of IRI.
Topics: Androstadienes; Animals; Disease Models, Animal; Dose-Response Relationship, Drug; Male; Myocardial Reperfusion Injury; Nerve Growth Factor; Nitric Oxide Synthase; Phosphatidylinositol 3-Kinase; Phosphoinositide-3 Kinase Inhibitors; Rats; Rats, Sprague-Dawley; Wortmannin; omega-N-Methylarginine
PubMed: 23314533
DOI: 10.1515/jbcpp-2012-0045 -
Biological Research Sep 2014Nitric oxide (NO) has been shown to be important in sperm function, and the concentration of NO appears to determine these effects. Studies have demonstrated both...
BACKGROUND
Nitric oxide (NO) has been shown to be important in sperm function, and the concentration of NO appears to determine these effects. Studies have demonstrated both positive and negative effects of NO on sperm function, but have not been able to provide a clear link between NO concentration and the extent of exposure to NO. To study the relationship between nitric oxide and sperm capacitation in vitro, and to provide a theoretical basis for the use of NO-related preparations in improving sperm motility for in vitro fertilization, we investigated the effects of NO concentration and time duration at these concentrations on in vitro sperm capacitation in both normal and abnormal sperm groups. We manipulated NO concentrations and the time duration of these concentrations using sodium nitroprusside (an NO donor) and NG-monomethyl-L-argenine (an NO synthase inhibitor).
RESULTS
Compared to the normal sperm group, the abnormal sperm group had a longer basal time to reach the appropriate concentration of NO (p < 0.001), and the duration of time at this concentration was longer for the abnormal sperm group (p < 0.001). Both the basal time and the duration of time were significantly correlated with sperm viability and percentage of progressive sperm (p < 0.001). The experimental group had a significantly higher percentage of progressive sperm than the control group (p < 0.001).
CONCLUSIONS
We hypothesize that there is a certain regularity to both NO concentration and its duration of time in regards to sperm capacitation, and that an adequate duration of time at the appropriate NO concentration is beneficial to sperm motility.
Topics: Adult; Cell Survival; Fertilization in Vitro; Humans; In Vitro Techniques; Male; Nitric Oxide; Nitric Oxide Synthase; Nitroprusside; Sperm Capacitation; Sperm Motility; Time Factors; omega-N-Methylarginine
PubMed: 25299622
DOI: 10.1186/0717-6287-47-44 -
Blood Oct 1999
Review
Topics: Anemia; Animals; Arginine; Bleeding Time; Blood Platelets; Endothelium, Vascular; Enzyme Inhibitors; Erythropoietin; Guanidines; Hemorrhage; History, 18th Century; History, 20th Century; Humans; Isoenzymes; Kidney Failure, Chronic; Nitric Oxide; Nitric Oxide Synthase; Nitroarginine; Rats; Succinates; Uremia; omega-N-Methylarginine
PubMed: 10515859
DOI: No ID Found -
Gut Sep 2001Luminal nitric oxide (NO) is greatly increased in the colon of patients with collagenous and ulcerative colitis. To define the source and consequence of enhanced NO...
BACKGROUND AND AIMS
Luminal nitric oxide (NO) is greatly increased in the colon of patients with collagenous and ulcerative colitis. To define the source and consequence of enhanced NO production we have studied expression of NO synthase (NOS) isoforms and nitrotyrosine in mucosal biopsies from these patients. In addition, effects on colonic fluid transfer caused by manipulating the substrate of NOS were studied in patients with collagenous colitis.
PATIENTS
Eight patients with collagenous colitis, nine with active ulcerative colitis, and 10 with uninflamed bowel were included.
METHODS
Expression of NOS isoforms was quantified by western blotting. Inducible NOS (iNOS) and nitrotyrosine were localised by immunohistochemistry. Modulation of NOS activity by topical N(G)-monomethyl-L-arginine (L-NMMA) or L-arginine was assessed during perfusion of whole colon. Plasma and perfusate nitrite/nitrate (NOx) was measured by Griess' reaction.
RESULTS
Both in collagenous and ulcerative colitis, expression of iNOS was 10(2)-10(3) higher (p<0.001) than in uninflamed bowel and localised primarily to the epithelium. Endothelial NOS was evenly expressed in all groups while neuronal NOS was undetectable. Nitrotyrosine was markedly expressed in active ulcerative colitis but rarely detected in collagenous colitis and never in uninflamed bowel. In collagenous colitis, the output of NOx was markedly increased compared with uninflamed bowel (283 (58) v <37 nmol/min; p<0.01) and fluid was net secreted. L-NMMA reduced the output of NOx by 13-66% (95% confidence intervals) and secretion of fluid by 25-109% whereas L-arginine increased the output of NOx by 3-39% and secretion of fluid by 15-93%.
CONCLUSIONS
In collagenous colitis, as opposed to ulcerative colitis, upregulation of iNOS occurs in the absence of nitrotyrosine formation and mucosal damage. Excess generation of NO may be the primary cause of diarrhoea in this condition.
Topics: Adult; Aged; Arginine; Blotting, Western; Body Fluids; Case-Control Studies; Colitis, Ulcerative; Confidence Intervals; Female; Humans; Intestinal Absorption; Male; Middle Aged; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type I; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Statistics, Nonparametric; Tyrosine; Up-Regulation; omega-N-Methylarginine
PubMed: 11511561
DOI: 10.1136/gut.49.3.387