Endothelial cell intracellular Ca concentration is increased upon breast tumor cell contact and mediates tumor cell transendothelial migration

Tumor cell extravasation is a determinant step in the process of hematogenous metastasis. The signal transduction pathways involved in the interactions between tumor cells and the vascular endothelium during transendothelial migration are still undefined. In the present study, we have investigated the influence of human breast adenocarcinoma cells (MCF7) on human umbilical vein endothelial cell (HUVEC) intracellular Ca²⁺ concentration ([Ca²⁺]i). We show that the contact between MCF7 cells and a confluent HUVEC monolayer induces an immediate and transient increase in HUVEC [Ca²⁺]i. This [Ca²⁺]i rise could not be elicited by tumor cell-conditioned medium, isolated tumor cell membranes, inert beads or normal breast epithelial cells, demonstrating the involvement of specific recognition mechanisms between MCF7 cells and HUVEC. Depletion of HUVEC intracellular Ca²⁺ stores by the endoplasmic reticulum Ca²⁺-ATPase inhibitor thapsigargin as well as the selective depletion of inositol 1,4,5-tri phosphate (IP3)-sensitive Ca²⁺ stores by prior activation of HUVEC using histamine resulted in a complete inhibition of tumor cell-induced [Ca²⁺]_i elevation. Similar results were obtained when HUVEC monolayers were treated with the tyrosine kinase inhibitor herbimycin A, suggesting a role for tyrosine kinase-associated cell surface receptors in tumor cell-endothelial cell interactions. The depletion of HUVEC intracellular Ca²⁺ stores by thapsigargin was also shown to delay MCF7-induced endothelial cell disjunction, to prevent their spreading on the subendothelial extracellular matrix and transendothelial migration in vitro. These results suggest that transient changes in endothelial [Ca²⁺]_i may govern multiple steps of tumor cell extravasation. © Rapid Science 1998     

Quasispecies heterogeneity and constraints on the evolution of the 5' noncoding region of hepatitis C virus (HCV): relationship with HCV resistance to interferon-alpha therapy

Hepatitis C virus (HCV) polyprotein translation depends on direct internal entry of the 40S ribosomal subunit mediated by an internal ribosome entry segment (IRES) located in the 5' noncoding (5'NC) region of the viral genome. HCV is genetically heterogeneous and is characterized by the existence of a quasispecies distribution of the virus population within a single infected individual. Cloning and sequencing strategies were used to characterize 5'NC quasispecies genetically. Similar to coding regions, the HCV 5'NC region was distributed as a quasispecies, but it appeared to be subjected to stronger conservatory constraints than other regions of the HCV genome, probably due to the need for structural (and functional) conservation of the IRES. Indeed, most of the quasispecies substitutions were in unpaired regions of the IRES or clustered such that base-pairing was maintained, whereas only 21% were expected to result in a loss of base-pairing. Quasispecies-related structural changes could be predicted in the core cruciform of IRES domain III composed of the RNA helices which extend from the four-way junction JIIIabc, mostly in minor variants, but sometimes in major ones. The results presented here suggest the simultaneous presence in infected patients of a mixture of genetically distinct but closely related IRES sequences that may have different structures. No significant genetic changes of 5'NC quasispecies were observed after interferon-alpha treatment, except in patients with mixed genotype infection who cleared one of the infecting strains during therapy, suggesting that the quasispecies distribution of IRES sequences does not play a role in HCV resistance to interferon-alpha therapy. In contrast, the overall quasispecies distribution of HCV genomes (including IRES sequences) might participate in regulation of hepatic and extrahepatic HCV replication.     

Sequential positron emission tomography using [18F]fluorodeoxyglucose for monitoring response to chemotherapy in metastatic breast cancer.

PURPOSE: To evaluate the clinical value of positron emission tomography (PET) for monitoring chemotherapy in metastatic breast cancer. EXPERIMENTAL DESIGN: Twenty patients with hormonorefractory or hormonoreceptor-negative multimetastatic breast cancer were prospectively included. PET studies were done at baseline, at day 21 after the first cycle and at day 21 after the third cycle of chemotherapy. Metabolic response was defined based on visual and various modes of standardized uptake value (SUV) analysis of sequential PET studies. RESULTS: After one cycle, PET indicated a partial response in 12 patients, stable disease in 7 patients, and progressive disease in 1 patient, according to the visual analysis. After three cycles, PET showed a complete response in 5 patients, partial response in 11 patients, stable disease in 3 patients, and progressive disease in 1 patient. Seventy-five percent of the patients showing a metabolic response on visual analysis effectively responded to the treatment. The average SUV decreased on both the second and the third PET study, but only changes measured after three cycles of chemotherapy predicted the clinical response to chemotherapy and the overall survival. All methods for calculating the SUV (normalized for body weight, body surface area, or lean body mass) provided similar results. CONCLUSION: Semiquantitative analysis of [18F]fluorodeoxyglucose-PET studies done after three cycles of chemotherapy is useful for monitoring the response to chemotherapy in metastatic breast cancer.     

Histologic grade, but not SYT-SSX fusion type, is an important prognostic factor in patients with synovial sarcoma: a multicenter, retrospective analysis.

PURPOSE: To assess the prognostic value of SYT-SSX fusion type, in comparison with other factors, in a population of 165 patients with synovial sarcoma (SS). PATIENTS AND METHODS: Data on 165 patients with SS (141 with localized disease at diagnosis) were studied retrospectively. The following parameters were examined for their potential prognostic value: age at diagnosis, sex, tumor site (extremities v proximal/truncal), size, histology, mitotic count, necrosis, histologic grade (Federation Nationale des Centres de Lutte Contre le Cancer system), stage (1997 tumor-node-metastasis system classification), surgical margin status (assessed histologically), and fusion type (SYT-SSX1 v SYT-SSX2). Median follow-up time was 37 months (range, 2 to 302 months). RESULTS: Among those patients with localized disease at diagnosis, median and 5-year disease-specific survivals (DSS) for the SYT-SSX1 and SYT-SSX2 subgroups were 126 months and 67.4% versus 82 months and 63.2%, respectively (P = .12). Median and 5-year metastasis-free survivals (MFS) were 84 months and 54.2% for SYT-SSX1 versus 50 months and 47.6% for SYT-SSX2 (P = .76). Univariate analyses showed that high histologic grade (grade 3), high mitotic count (>/= 10 mitoses/10 high-power fields), stage III disease, size greater than 7 cm, tumor necrosis, and presence of areas of poorly differentiated morphology were significant adverse prognostic factors for DSS and MFS, whereas SYT-SSX fusion type, tumor histology (biphasic v monophasic), and patient sex were not. Age greater than 35 years adversely affected DSS but not MFS. In multivariate analyses, histologic grade was the most significant prognostic factor for both DSS and MFS. CONCLUSION: For patients with localized SS, histologic grade but not SYT-SSX fusion type is a strong predictor of survival.     

Chronic renal failure and portal hypertension – is portosystemic shunt indicated?

We report two girls with histories of recessive polycystic kidney disease. Both were on maintenance hemodialysis. They had undergone surgical distal portocaval shunt because of portal hypertension. Later, bilateral nephrectomy was performed, and they presented with hepatic encephalopathy (HE) and evolution towards irreversible hepatic coma and death. Portosystemic shunt is the treatment of choice of portal hypertension. The kidney plays a pivotal role in ammonia disposal during portosystemic shunt. Thus, we stress the risk of HE after portosystemic shunt followed by bilateral nephrectomy in patients with end-stage renal failure and suggest that combined liver-kidney transplantation should be considered. Received: 18 May 1999 / Revised: 8 November 1999 / Accepted: 9 November 1999     

Endovascular Treatment of Iliac Aneurysms with Covered Stents

n = 26) or two overlapping (n= 7) covered stents. Mean procedure duration was 45 min (range, 25 to 75 min). The internal iliac artery was patent in 28 cases, but patency was preserved in only 4 cases. In the remaining 24 cases the internal iliac artery was excluded either preoperatively by embolization using Gianturco coils (n= 15) or intraoperatively by placement of the stent (n= 9). Endovascular treatment of iliac aneurysm with covered stents achieves good short- and middle-term results but usually requires exclusion of the internal iliac artery.     

Early versus late coronary stenting following acute myocardial infarction: Results of the STENTIM I Study (French Registry of Stenting in Acute Myocardial Infarction)

This study was undertaken to determine the feasibility and safety of coronary stenting in acute myocardial infarction (AMI). In AMI, primary percutaneous transluminal coronary angioplasty (PTCA) is accepted as the preferred method of reperfusion for patients presenting at highly experienced centres. Until recently, however, stenting has been avoided during AMI because of a potential high risk of thrombosis. This prospective observational study carried out in 20 centres and included 648 consecutive patients who underwent PTCA with stent implantation for AMI. Of these 648 patients, 269 (41.5%, Group 1) were dilated early (<24 hr) after the onset of the symptoms (75% treated by direct PTCA) and 379 (58.5%, Group 2) were dilated between 24 hr and 14 days after AMI. Combined therapy with ticlopidin and aspirin was used after the procedure. Bailout stenting occurred more often in Group 1 than in Group 2 (17% vs. 9.5%)(P < 0.05). Angiographic successful stenting was similar in both groups of patients (96% vs. 97%). During the hospital follow-up period, stent thrombosis occurred in eight patients (3%) in Group 1 and in six patients (1.6%) in Group 2 (NS). There was 14 deaths (5.2%) in Group 1 and 11 deaths (3.9%) in Group 2 (NS). After multivariate analysis bailout stenting was identified as the sole predictor of stent thrombosis (P < 0.0001). Vascular access-site complications occurred in six patients (1%) with no difference between the two groups. This study indicates that patients who receive a coronary stent in AMI can be managed safely with antiplatelet therapy. Randomized studies are needed to determine the precise indication for coronary stenting as an adjunct to primary PTCA. Cathet. Cardiovasc. Diagn. 42:243–248, 1997. © 1997 Wiley-Liss, Inc.     

Hospital outcome after bailout coronary stenting in patients with acute myocardial infarction

We evaluated the outcome of bailout coronary stenting in acute myocardial infarction. Fifty patients (35 men, mean age 60 plusmn; 12) with acute myocardial infarction consecutively underwent bailout stenting after primary and rescue coronary angioplasty (n=41 and 9, respectively). Cardiogenic shock was present in six patients, and 17 others had contraindications to thrombolysis. Stent implantation was successful in 49/50 patients. The antithrombotic regimen combined heparin, aspirin, and ticlopidine. One patient had symptomatic stent closure. Predischarge angiography in 41/44 survivors showed widely patent stents in 40/41 patients. Six patients (4 of whom had been admitted with cardiogenic shock) died in the hospital. During acute myocardial infarction, bailout stenting can achieve high TIMI grade 3 coronary patency (here, 92%), and low acute stent closure rates (here, 2%). However, in-hospital mortality remained high, at nearly 10%, mainly due to the severe risk profile in this patient subset. Cathet. Cardiovasc. Diagn. 44:371–377, 1998. © 1998 Wiley-Liss, Inc.     

Inhibition of stromal matrix metalloproteases: Effects on breast-tumor promotion by fibroblasts

Co-injection of fibroblasts with human epithelial breast-tumor MCF7 cells in the presence of Matrigel enhances tumor growth in nude mice. While most of the matrix metalloproteinases (MMPs) have been shown to be produced by stromal cells, tumor cells such as MCF7 cells are unable to produce MMPs. We therefore, hypothesized that the tumor-promoting effect of fibroblasts could be related to their production of MMPs. In order to inhibit stromal proteases, over-production of TIMP-2 was induced in MCF7 cells by in vitro retroviral-mediated gene transfer. TIMP-2-producing MCF7 cells were then co-injected with fibroblasts into nude mice. Alternatively, we evaluated the effect of Batimastat, a synthetic inhibitor of MMPs, on the tumorigenicity of MCF7 cells co-inoculated with fibroblasts into nude mice. Both physiological (TIMP-2) and synthetic (Batimastat) inhibitors of MMPs were able to abolish the tumor-promoting effect of fibroblasts. On the contrary, they failed to modulate the tumorigenicity of MCF7 cells injected alone. Interestingly, Matrigel from which low-molecular-weight proteins or growth factors had been removed failed to favor the tumorigenicity of MCF7 cells inoculated with fibroblasts. These findings emphasize the importance of fibroblasts in cancer progression, and suggest that their role could be related at least in part to production of proteases which can induce the release of factors from the extracellular matrix. Int. J. Cancer 76:267–273, 1998.© 1998 Wiley-Liss, Inc.