ABSTRACT
Endothelial cell injury/dysfunction is considered to play a critical role in the pathogenesis of severe sepsis and septic shock. Although it is considered that endothelial cell apoptosis is involved in endothelial injury/dysfunction, physiological involvement remains ambiguous since the induction of apoptosis requires the inhibition of endogenous apoptosis inhibitors. Here we show that caspase-3 activation, a biological indicator of apoptosis, is observed in response to lipopolysaccharide (LPS) stimulation even under the influence of endogenous apoptosis inhibitors, and that activated caspase-3 is rapidly released from human umbilical vein endothelial cells (HUVEC). In the presence of cycloheximide (CHX), an increase in intracellular caspase-3/7 activity in response to LPS was not detected in HUVEC up to 24 h following stimulation even in the presence of LPS-binding protein (LBP), soluble CD14 and soluble MD-2, whereas the decrease in cell viability and increase in release of the cellular enzyme lactate dehydrogenase (LDH) were observed in a soluble CD14/LBP-dependent manner. On the other hand, even in the absence of CHX, a significant increase in caspase-3/7 activity and a cleaved caspase-3 fragment with a slight increase in LDH release was observed in culture supernatants in response to LPS. This increase in caspase-3/7 activity was observed even when LDH release was undetected. These results indicate that caspase-3 is activated by LPS under physiological conditions and suggest that HUVEC escape from cell death by rapidly releasing activated caspase-3 into extracellular space. Failure of this escape mechanism may result in endothelial injury/dysfunction.
Subject(s)
Caspase 3/metabolism , Endothelial Cells/drug effects , Endothelial Cells/metabolism , Lipopolysaccharides/pharmacology , Umbilical Veins/cytology , Animals , Caspase 7/metabolism , Cell Survival/drug effects , Cells, Cultured , Endothelial Cells/cytology , Endothelial Cells/enzymology , Enzyme Activation/drug effects , Humans , Intracellular Space/drug effects , Intracellular Space/enzymology , L-Lactate Dehydrogenase/metabolism , Mice , Subcellular Fractions/drug effects , Subcellular Fractions/enzymology , Time FactorsABSTRACT
The patient was a 61-year-old man who was referred to our hospital with a complaint of epigastric pain. Upper gastrointestinal endoscopy and X-ray examination of the stomach revealed type 3 cancer in the gastric antrum, extending to the middle body. It was about 9 cm in diameter, and the biopsy specimen revealed moderately differentiated tubular adenocarcinoma. Abdominal CT scan showed marked enlargement of No. 3 lymph nodes along the lesser curvature of the stomach. Examination of the blood showed a hemoglobin of 10.2 g/dl, CEA 5.8 ng/ml, CA19-9 330.5 U/ml. For this gastric cancer, clinical Stage IIIA (cT3N1HOPOMO), neoadjuvant chemotherapy with TS-1/CDDP was planned. TS-1 (120 mg/day) was orally administered for 3 weeks followed by a drug-free-2-week period as the first course, and 93 mg (60 mg/m2) of CDDP administered by intravenous drip on day 8. There were grade 2 nausea and grade 3 appetite loss by intravenous administration of CDDP in the second course. An upper GI series revealed 33% reduction of gastric cancer, and laboratory studies CEA and CA 19-9 showed normal values. One month after the second course of chemotherapy, total gastrectomy, splenectomy and lymph node dissection D2 were performed. The pathological specimens showed no cancer cells in the surgically obtained stomach and lymph nodes, so the histological effect was Grade 3. The postoperative course was satisfactory, and he now attends outpatient department without any findings of recurrence 12 months after the operation. TS-1/CDDP chemotherapy produced a high response in this case, and it may be useful as neoadjuvant chemotherapy for advanced gastric cancer.
