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1.
Dis Esophagus ; 32(8)2019 Aug 01.
Article in English | MEDLINE | ID: mdl-30597022

ABSTRACT

The standard of care trimodality therapy for resectable locally advanced esophageal adenocarcinoma is complex and necessitates multidisciplinary care and expertise. In this work, it is hypothesized that facility clinical volume and utilization of intensity-modulated radiotherapy (IMRT) may influence outcomes. The National Cancer Data Base was queried for patients with cT1-4-N0-3 M0 esophageal adenocarcinoma undergoing trimodality therapy from 2004 to 2013 (n = 2445). All patients received chemoradiation followed by esophagectomy at a Commission on Cancer facility. The facility volume was categorized into tertiles: high-volume centers (HVCs) in the highest 25th percentile of cases per year, intermediate-volume centers (IVCs) with the next highest 25th percentile of cases, and low- and very low-volume centers (LVCs) in the lowest 50th percentile. Overall survival (OS) was estimated using Kaplan-Meier methods and Cox proportional hazard regression. Propensity score matching to balance patient characteristics between volume centers was performed. Subgroup analysis was done comparing IMRT versus 3D conformal radiotherapy. The median follow-up was 26 months. Treatment at an HVC (hazard ratio 0.63, 95% CI 0.49-0.81, P < 0.001) was found to be independently associated with improved overall survival in multivariable analysis. Three-year OS was 58.4%, 46.2%, and 47.5% for HVCs, IVCs, and LVCs, respectively (P < 0.001). Patients at HVCs were more likely to receive IMRT over 3D chemoradiation (CRT; OR 3.45, 95% CI 2.4-5.0, P < 0.001). Patients treated using IMRT at HVCs had improved OS compared to those treated at IVCs or LVCs (HR 0.68, 95% CI 0.52-0.90, P < 0.01), while patients treated with 3D CRT at HVCs had no survival advantage over those at IVCs or LVCs (P = 0.28). Patients with locally advanced esophageal adenocarcinoma treated with IMRT and at HVCs appear to have improved survival.


Subject(s)
Adenocarcinoma/mortality , Chemoradiotherapy/mortality , Esophageal Neoplasms/mortality , Esophagectomy/mortality , Hospitals, High-Volume/statistics & numerical data , Radiotherapy, Intensity-Modulated/mortality , Adenocarcinoma/therapy , Aged , Antineoplastic Protocols , Chemoradiotherapy/methods , Combined Modality Therapy , Esophageal Neoplasms/therapy , Esophagectomy/methods , Female , Humans , Male , Middle Aged , Propensity Score , Proportional Hazards Models , Radiotherapy, Conformal/methods , Radiotherapy, Conformal/mortality , Radiotherapy, Intensity-Modulated/methods , Treatment Outcome
2.
Dis Esophagus ; 30(7): 1-9, 2017 Jul 01.
Article in English | MEDLINE | ID: mdl-30052899

ABSTRACT

We compared pathologic complete response (pCR) rate, toxicity, and postoperative complications between patients treated preoperatively with 50.4 Gy versus dose escalation with dose-painting intensity-modulated radiation therapy (dp-IMRT) to 56 Gy in locally advanced esophageal cancer. We evaluated esophageal cancer patients treated between 2006 and 2014 with preoperative IMRT chemoradiation to a dose of 50.4 Gy versus 56 Gy. The endpoints were pCR and toxicity. We identified 113 patients (50.4 Gy: n = 40; 56 Gy: n = 73). There were no significant differences in tumor or patient characteristics. Patients treated with 56 Gy demonstrated a higher pCR rate (56.2% vs. 30.0%) and lower pathologic nonresponse rate (4.1% vs. 20.0%) compared to patients treated to 50.4 Gy (P = 0.008). This remained significant on multivariate analysis (OR 3.375 95%CI 1.3-8.8, P = 0.013). Patients treated to 56 Gy also had an improved 3-year locoregional control rate compared to those treated to 50.4 Gy (93.8% vs. 78.5%; P = 0.022). The estimated 3-year freedom from failure was also superior in the 56 Gy arm (73.7% vs. 52.2%; P = 0.051), approaching significance. There were no differences in treatment related grade ≥3 toxicities, hospital admissions, feeding tube, esophageal stent placement, or dilation. There was, however, a statistically significant increase in postoperative atrial fibrillation in patients treated with 56 Gy (30.1% vs. 12.5%; P = 0.036). There was no difference in postoperative 30 or 60 day mortality. Dose escalation to 56 Gy with dp-IMRT is safe and results in significantly higher complete pathologic response rates in esophageal cancer without an increase in treatment-related toxicity. Prospective trials using dp-IMRT are needed to address the role of dose escalation on pCR rate and survival in esophageal cancer.


Subject(s)
Esophageal Neoplasms/therapy , Radiotherapy, Intensity-Modulated/methods , Adult , Aged , Aged, 80 and over , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Atrial Fibrillation/etiology , Chemoradiotherapy, Adjuvant/adverse effects , Chemoradiotherapy, Adjuvant/methods , Cisplatin/administration & dosage , Disease-Free Survival , Esophageal Neoplasms/diagnostic imaging , Esophageal Neoplasms/pathology , Esophagectomy , Female , Fluorouracil/administration & dosage , Humans , Male , Middle Aged , Neoadjuvant Therapy/adverse effects , Neoadjuvant Therapy/methods , Positron Emission Tomography Computed Tomography , Radiotherapy Dosage , Radiotherapy, Intensity-Modulated/adverse effects , Retrospective Studies , Survival Rate , Treatment Outcome
3.
Dis Esophagus ; 28(8): 782-7, 2015.
Article in English | MEDLINE | ID: mdl-25155802

ABSTRACT

Survival in patients with metastatic esophageal and gastric cancer is dismal. No standard treatment has been established. Carboplatin/paclitaxel is active in both advanced gastric and esophageal cancer. Here we retrospectively present our single center experience. Between 1998 and 2013, a total of 134 patients with metastatic esophageal and gastric adenocarcinoma treated with carboplatin/paclitaxel (carboplatin predominantly area under the curve 5 and paclitaxel predominantly 175 mg/m(2)) every 3 weeks as first-line therapy were identified. Baseline characteristics, response to therapy, toxicities, and survival in this patient population were evaluated. Overall survival was defined as date from diagnosis to death or last follow up, and progression-free survival was defined at time from cycle 1 to, progression or last follow up. Kaplan-Meier curves were fit to estimate overall and progression-free survival. Of the 134 patients evaluated, the median age at diagnosis was 65 years. Disease control rate was 62.6% (complete response: 11%, partial response: 28%, stable disease: 33%). Median overall survival from date of initial diagnosis was 15.5 months (95% confidence interval [CI] 1.06-1.5). Median progression-free survival from date of initiation of carboplatin and paclitaxel was 5.3 months (95% CI 0.34-0.5). Grade III or greater toxicity occurred in 26.1% of patients. The most common grade III toxicities were neutropenia and neuropathy, present in 14.2% and 3.7% of the total study population, respectively. In patients with metastatic or unresectable esophageal or gastric cancer, the combination of carboplatin and paclitaxel is well tolerated with comparable overall survival and progression-free survival to existing regimens in this population.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Carboplatin/administration & dosage , Esophageal Neoplasms/drug therapy , Paclitaxel/administration & dosage , Stomach Neoplasms/drug therapy , Aged , Disease-Free Survival , Esophageal Neoplasms/pathology , Female , Humans , Kaplan-Meier Estimate , Lymphatic Metastasis , Male , Middle Aged , Neutropenia/chemically induced , Retrospective Studies , Stomach Neoplasms/pathology
4.
Dis Esophagus ; 28(4): 352-7, 2015.
Article in English | MEDLINE | ID: mdl-24635657

ABSTRACT

Emerging data suggests a benefit for using intensity modulated radiation therapy (IMRT) for the management of esophageal cancer. We retrospectively reviewed patients treated at our institution who received definitive or preoperative chemoradiation with either IMRT or 3D conformal radiation therapy (3DCRT) between October 2000 and January 2012. Kaplan Meier analysis and the Cox proportional hazard model were used to evaluate survival outcomes. We evaluated a total of 232 patients (138 IMRT, 94 3DCRT) who received a median dose of 50.4 Gy (range, 44-64.8) to gross disease. Median follow up for all patients, IMRT patients alone, and 3DCRT patients alone was 18.5 (range, 2.5-124.2), 16.5 (range, 3-59), and 25.9 months (range, 2.5-124.2), respectively. We observed no significant difference based on radiation technique (3DCRT vs. IMRT) with respect to median overall survival (OS) (median 29 vs. 32 months; P = 0.74) or median relapse free survival (median 20 vs. 25 months; P = 0.66). On multivariable analysis (MVA), surgical resection resulted in improved OS (HR 0.444; P < 0.0001). Superior OS was also associated on MVA with stage I/II disease (HR 0.523; P = 0.010) and tumor length ≤5 cm (HR 0.567; P = 0.006). IMRT was also associated on univariate analysis with a significant decrease in acute weight loss (mean 6% + 4.3% vs 9% + 7.4%, P = 0.012) and on MVA with a decrease in objective grade ≥3 toxicity, defined as any hospitalization, feeding tube, or >20% weight loss (OR 0.51; P = 0.050). Our data suggest that while IMRT-based chemoradiation for esophageal cancer does not impact survival there was significantly less toxicity. In the IMRT group there was significant decrease in weight loss and grade ≥3 toxicity compared to 3DCRT.


Subject(s)
Esophageal Neoplasms/therapy , Imaging, Three-Dimensional , Radiotherapy, Conformal/mortality , Radiotherapy, Conformal/methods , Aged , Analysis of Variance , Antineoplastic Agents/therapeutic use , Chemoradiotherapy/methods , Esophageal Neoplasms/mortality , Female , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Neoplasm Recurrence, Local , Neoplasm Staging , Proportional Hazards Models , Radiation Effects , Radiotherapy, Intensity-Modulated , Retrospective Studies , Survival Analysis , Treatment Outcome , Weight Loss
5.
Br J Cancer ; 111(10): 1932-44, 2014 Nov 11.
Article in English | MEDLINE | ID: mdl-25290091

ABSTRACT

BACKGROUND: Two strategies to interrogate the insulin growth factor 1 receptor (IGF-1R) pathway were investigated: vertical inhibition with dalotuzumab and MK-2206 or ridaforolimus to potentiate PI3K pathway targeting and horizontal cross-talk inhibition with dalotuzumab and MK-0752 to exert effects against cellular proliferation, angiogenesis, and stem cell propagation. METHODS: A phase I, multi-cohort dose escalation study was conducted in patients with advanced solid tumours. Patients received dalotuzumab (10 mg kg(-1)) and escalating doses of MK-2206 (90-200 mg) or escalating doses of dalotuzumab (7.5-10 mg kg(-1)) and MK-0752 (1800 mg) weekly. Upon maximum tolerated dose determination, patients with low-RAS signature, high-IGF1 expression ovarian cancer were randomised to dalotuzumab/MK-2206 versus dalotuzumab/ridaforolimus, whereas patients with high IGF1/low IGF2 expression colorectal cancer received dalotuzumab/MK-0752. RESULTS: A total of 47 patients were enrolled: 29 in part A (18 in the dalotuzumab/MK-2206 arm and 11 in the dalotuzumab/MK-0752 arm) and 18 in part B (6 in each arm). Dose-limiting toxicities (DLTs) for dalotuzumab/MK-2206 included grade 4 neutropenia and grade 3 serum sickness-like reaction, maculopapular rash, and gastrointestinal inflammation. For dalotuzumab/MK-0752, DLTs included grade 3 dehydration, rash, and diarrhoea. Seven patients remained on study for >4 cycles. CONCLUSIONS: Dalotuzumab/MK-2206 and dalotuzumab/MK-0752 combinations were tolerable. Further developments of prospectively validated predictive biomarkers to aid in patient selection for anti-IGF-1R therapies are needed.


Subject(s)
Antibodies, Monoclonal/therapeutic use , Benzene Derivatives/therapeutic use , Heterocyclic Compounds, 3-Ring/therapeutic use , Neoplasms/drug therapy , Propionates/therapeutic use , Sirolimus/analogs & derivatives , Sulfones/therapeutic use , Adult , Aged , Aged, 80 and over , Antibodies, Monoclonal/pharmacokinetics , Antibodies, Monoclonal, Humanized , Antineoplastic Combined Chemotherapy Protocols , Benzene Derivatives/pharmacokinetics , Biomarkers, Tumor/metabolism , Clinical Trials, Phase II as Topic , Clinical Trials, Phase III as Topic , Cohort Studies , Female , Follow-Up Studies , Heterocyclic Compounds, 3-Ring/pharmacokinetics , Humans , Male , Middle Aged , Neoplasm Staging , Neoplasms/metabolism , Neoplasms/pathology , Prognosis , Propionates/pharmacokinetics , Proto-Oncogene Proteins c-akt/antagonists & inhibitors , Randomized Controlled Trials as Topic , Receptor, IGF Type 1/antagonists & inhibitors , Receptors, Notch/antagonists & inhibitors , Sirolimus/pharmacokinetics , Sirolimus/therapeutic use , Sulfones/pharmacokinetics , TOR Serine-Threonine Kinases/antagonists & inhibitors , Tissue Distribution
6.
Eur J Surg Oncol ; 37(9): 791-7, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21741199

ABSTRACT

BACKGROUND: In the absence of prospective data, the use of adjuvant therapy in ampullary adenocarcinoma is contingent upon the clinicopathological features which can correlate to 5-year post-operative survival and disease relapse. METHODS: We investigated the factors associated with clinical outcomes among 72 patients who underwent pancreatoduodenectomy at the Cleveland Clinic from 1995 to 2007 for histologically confirmed adenocarcinoma of the ampulla of Vater. RESULTS: R0 resection was achieved in 96% of patients (median age, 72 years; 58% males, 89% Caucasians). Nineteen patients experienced disease relapse after surgery and 61% were alive within 5 years of follow up. Thirty five percent of patients received some form of adjuvant therapy. Perineural tumor invasion (p < 0.01) and presence of ulcerated tumor on histopathology (p < 0.01) were associated with higher rates of tumor relapse and poor 5-year overall survival in multivariable analysis. Lymph node involvement (p = 0.02) also portended poor overall survival after adjustment for other covariates. Although adjuvant therapy was associated with poor clinical outcomes in univariate analysis, it demonstrated a favorable albeit non-significant trend in multivariable analysis. CONCLUSIONS: Factors associated with poor clinical outcomes in this contemporary single-institution study, included perineural invasion, tumor ulceration, and lymph node involvement. No definite conclusion could be made in regards to adjuvant treatment.


Subject(s)
Adenocarcinoma/surgery , Ampulla of Vater , Common Bile Duct Neoplasms/surgery , Adenocarcinoma/mortality , Adenocarcinoma/pathology , Adenocarcinoma/secondary , Adult , Aged , Aged, 80 and over , Common Bile Duct Neoplasms/mortality , Common Bile Duct Neoplasms/pathology , Female , Humans , Lymphatic Metastasis , Male , Middle Aged , Pancreaticoduodenectomy , Survival Analysis , Survival Rate
7.
Curr Cancer Drug Targets ; 10(3): 319-31, 2010 May.
Article in English | MEDLINE | ID: mdl-20370686

ABSTRACT

The present study is the first to show in pancreatic cancer (PC) the growth inhibition and apoptosis by novel MDM2 inhibitors (MI-319 & 219) through reactivation of p53 pathway. Our results highlight two new secondary targets of MDM2 inhibitor 'SIRT1' and Ku70. SIRT1 which has a role in ageing and cancer and is known to regulate p53 signaling through acetylation. Ku70 is a key component of non-homologous end joining machinery in the DNA damage pathway and is known to regulate apoptosis by blocking Bax entry into mitochondria. Growth inhibition and apoptosis by MI-219, MI-319 was accompanied by increase in levels of p53 along with p21(WAF1) and the proapoptotic Puma. SiRNA against p21(WAF1) abrogated the growth inhibition of PC cells confirming p21(WAF1) as a key player downstream of activated p53. Immunoprecipitation-western blot analysis revealed reduced association of MDM2-p53 interaction in drug exposed PC cells. In combination studies, the inhibitors synergistically augmented anti-tumor effects of therapeutic drug gemcitabine both in terms of cell growth inhibition as well as apoptosis. Surface plasmon resonance studies confirmed strong binding between MI-319 and Ku70 (K(D) 170 nM). Western blot revealed suppression of SIRT1 and Ku70 with simultaneous upregulation of acetyl-p53 (Lys379) and Bax. Co-Immunoprecipitation studies confirmed that MI-319 could disrupt Ku70-Bax and SIRT1-Bax interaction. Further, using wt-p53 xenograft of Capan-2, we found that oral administration of MI-319 at 300 mg/kg for 14 days resulted in significant tumor growth inhibition without any observed toxicity to the animals. No tumor inhibition was found in mut-p53 BxPC-3 xenografts. In light of our results, the inhibitors of MDM2 warrant clinical investigation as new agents for PC treatment.


Subject(s)
Antineoplastic Agents/pharmacology , Enzyme Inhibitors/pharmacology , Indoles/pharmacology , Pancreatic Neoplasms/drug therapy , Proto-Oncogene Proteins c-mdm2/antagonists & inhibitors , Spiro Compounds/pharmacology , Tumor Suppressor Protein p53/metabolism , Animals , Antigens, Nuclear/metabolism , Apoptosis/drug effects , Blotting, Western , Cell Cycle/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Cyclin-Dependent Kinase Inhibitor p21/metabolism , DNA-Binding Proteins/metabolism , Deoxycytidine/analogs & derivatives , Deoxycytidine/pharmacology , Dose-Response Relationship, Drug , Female , Humans , Immunoprecipitation , Ku Autoantigen , Mice , Mice, Inbred ICR , Mice, SCID , Pancreatic Neoplasms/enzymology , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/pathology , Protein Binding , Proto-Oncogene Proteins c-mdm2/metabolism , RNA Interference , Sirtuin 1/metabolism , Surface Plasmon Resonance , Time Factors , Transfection , Tumor Burden , Tumor Suppressor Protein p53/genetics , Xenograft Model Antitumor Assays , bcl-2-Associated X Protein/metabolism , Gemcitabine
8.
Ann Oncol ; 21(10): 1999-2004, 2010 Oct.
Article in English | MEDLINE | ID: mdl-20332133

ABSTRACT

BACKGROUND: Bevacizumab has demonstrated antitumor activity in multiple diseases. This phase II study was undertaken to determine the effects of adding bevacizumab to a regimen of docetaxel and oxaliplatin in patients with advanced adenocarcinoma of the stomach or gastroesophageal junction. PATIENTS AND METHODS: Previously untreated patients with locally advanced or metastatic disease and a performance status (PS) of 0-1 were eligible for this study. Patients received bevacizumab at 7.5 mg/kg, docetaxel at 70 mg/m(2), and oxaliplatin at 75 mg/m(2) administered on day 1 of a 21-day cycle. The primary end point of the study was progression-free survival (PFS). RESULTS: A total of 38 eligible patients (median age 57 years, 45% gastric, 55% PS 0) were enrolled on to the study. Median PFS was 6.6 months [95% confidence interval (CI) 4.4-10.5] and median survival 11.1 months (95% CI 8.2-15.3). Complete responses were documented in 2 (5%) patients, partial responses in 14 (37%), and stable disease in 14 (37%). No treatment-related deaths were observed. The most commonly reported grade 3-4 toxicity was neutropenia (34%), and gastrointestinal perforation occurred in three patients (8%). CONCLUSION: The combination of bevacizumab, docetaxel, and oxaliplatin has promising activity for further evaluation in randomized trials.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Bone Neoplasms/drug therapy , Esophagogastric Junction/drug effects , Liver Neoplasms/drug therapy , Lung Neoplasms/drug therapy , Peritoneal Neoplasms/drug therapy , Stomach Neoplasms/drug therapy , Adenocarcinoma/drug therapy , Adenocarcinoma/secondary , Adult , Aged , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal, Humanized , Bevacizumab , Bone Neoplasms/secondary , Docetaxel , Esophagogastric Junction/pathology , Female , Humans , Liver Neoplasms/secondary , Lung Neoplasms/secondary , Male , Middle Aged , Neoplasm Staging , Organoplatinum Compounds/administration & dosage , Oxaliplatin , Peritoneal Neoplasms/secondary , Stomach Neoplasms/pathology , Survival Rate , Taxoids/administration & dosage , Treatment Outcome
9.
J Neurochem ; 79(6): 1136-48, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11752055

ABSTRACT

The regulation of Schwann cell (SC) proliferation and morphology is critical to nerve homeostasis. We have previously reported that endothelins (ETs) regulate the activity of different effectors in SC including adenylyl cyclase, phospholipases C and A2 and mitogen-activated protein kinases (MAPKs). These effects imply a possible participation of ETs in the regulation of SC phenotype. We have now investigated the effects of endothelins on the proliferation and morphology of SC, and compared them with the responses to platelet-derived growth factor (PDGF), a known mitogen in these cells. Both endothelin-1 (ET-1) and PDGF increased the incorporation of [3H]thymidine and the proportion of SC in S and G2/M, with a concomitant decrease in the G0/G1 stage cells. Treatment with ET-1 produced rapid changes in the morphology of the SC, characterized by the appearance of cell spreading with shorter processes. The response to ET-1 was considered to represent a proliferative phenotype, in contrast to the effects of forskolin, which decreased [3H]thymidine incorporation in immortalized SC (iSC) and lead to a differentiated morphology with longer extensions. While both ET-1 and PDGF displayed a proliferative effect on SC, treatment with PDGF did not affect the morphology of these cells to a significant extent. A role for p38 MAPK and Ca(2+)-independent phospholipase A2 in the changes in morphology and proliferation of iSC driven by ET-1 was suggested by the effects of selective inhibitors of these pathways [SB202190 and HELSS, respectively]. The unique pattern of signaling pathways recruited by ET-1 and its combined effects on regulation of phenotype and proliferation of SC suggest an important role for this peptide during nerve degeneration/regeneration.


Subject(s)
Endothelin-1/pharmacology , Mitogen-Activated Protein Kinases/physiology , Nerve Tissue Proteins/physiology , Phospholipases A/physiology , Protein Serine-Threonine Kinases , Schwann Cells/drug effects , Signal Transduction/drug effects , Actins/analysis , Animals , Bucladesine/pharmacology , Cell Division/drug effects , Cell Line, Transformed/drug effects , Cell Size/drug effects , Cell Surface Extensions/drug effects , Cells, Cultured/drug effects , Colforsin/pharmacology , Culture Media, Serum-Free , Enzyme Inhibitors/pharmacology , Focal Adhesions/drug effects , Group VI Phospholipases A2 , Imidazoles/pharmacology , MAP Kinase Signaling System/drug effects , Microscopy, Fluorescence , Mitogen-Activated Protein Kinases/antagonists & inhibitors , Naphthalenes/pharmacology , Nerve Tissue Proteins/antagonists & inhibitors , Phosphatidylinositol 3-Kinases/physiology , Phosphoinositide-3 Kinase Inhibitors , Phospholipases A/antagonists & inhibitors , Phospholipases A2 , Phosphorylation/drug effects , Platelet-Derived Growth Factor/pharmacology , Protein Processing, Post-Translational/drug effects , Proto-Oncogene Proteins/metabolism , Proto-Oncogene Proteins c-akt , Pyridines/pharmacology , Pyrones/pharmacology , Rats , Schwann Cells/metabolism , Schwann Cells/ultrastructure , Stress Fibers/drug effects , Vinculin/analysis , p38 Mitogen-Activated Protein Kinases
10.
J Neurochem ; 75(6): 2316-26, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11080183

ABSTRACT

Immortalized rat Schwann cells (iSC) express endothelin (ET) receptors coupled to inhibition of adenylyl cyclase and stimulation of phospholipase C (PLC). These effects precede phenotypic changes and increased DNA synthesis. We have investigated the role of ETs in the regulation of arachidonic acid (AA) release and mitogen-activated protein kinases (MAPKs). Both ET-1 and ET-3 increased AA release in iSC. This effect was sensitive to the phospholipase A(2) (PLA(2)) inhibitors E:-6-(bromomethylene)tetrahydro-3-(1-naphthalenyl)-2H:-pyran-2-one and arachidonyl-trifluoromethyl ketone but was insensitive to inhibitors of PLC or phospholipase D-dependent diacylglycerol generation. ET-1-dependent AA release was also unaffected by removal of extracellular Ca(2+) and blocking the concomitant elevation in [Ca(2+)](i), consistent with participation of a Ca(2+)-independent PLA(2). Treatment of iSC with ETs also resulted in activation of extracellular signal-regulated kinase, c-Jun-NH(2)-terminal kinase (JNK), and p38 MAPK. A cause-effect relationship between agonist-dependent AA release and stimulation of MAPKs, but not the opposite, was suggested by activation of JNK by exogenous AA and by the observation that inhibition of MAPK kinase or p38 MAPK was inconsequential to ET-1-induced AA release. Similar effects of ETs on AA release and MAPK activity were observed in cultures expanded from primary SC and in iSC. Regulation of these effectors may mediate the control of proliferation and differentiation of SC by ETs during peripheral nerve development and regeneration.


Subject(s)
Arachidonic Acid/metabolism , Endothelin-1/metabolism , Endothelin-3/metabolism , Mitogen-Activated Protein Kinases/metabolism , Schwann Cells/metabolism , Adenylate Cyclase Toxin , Animals , Arachidonic Acid/pharmacology , Calcium/metabolism , Cells, Cultured , Chelating Agents/pharmacology , Colforsin/pharmacology , Endothelin-1/pharmacology , Endothelin-3/pharmacology , Enzyme Inhibitors/pharmacology , Intracellular Fluid/metabolism , Ionophores/pharmacology , Mitogen-Activated Protein Kinase 1/metabolism , Mitogen-Activated Protein Kinase 3 , Phospholipases/antagonists & inhibitors , Protein Kinase C/antagonists & inhibitors , Rats , Schwann Cells/cytology , Schwann Cells/drug effects , Signal Transduction/drug effects , Virulence Factors, Bordetella/pharmacology
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