Endothelin-receptor antagonists are proapoptotic and antiproliferative in human colon cancer cells

Endothelin (ET)-1 can act as an autocrine/paracrine growth factor or an antiapoptotic factor in human cancers. To study the role of ET-1 in human colon cancer, proliferation and apoptosis of colon carcinoma cells was investigated using human HT-29 and SW480 colon carcinoma cells. ET-1 was secreted by these cells. Treatment of cells with bosentan, a dual ET(A/B)-receptor antagonist, decreased cell number. Inhibition of DNA synthesis by bosentan was observed only in the presence of serum. Exogenously added ET-1 did not increase DNA synthesis in serum-deprived cells. SW480 cells were sensitive and HT-29 cells were resistant to FasL-induced apoptosis. Bosentan sensitised resistant HT-29 cells to FasL-induced, caspase-mediated apoptosis, but not to TNF-alpha-induced apoptosis. Bosentan and/or FasLigand (FasL) did not modulate the expression of caspase-8 or FLIP. Bosentan sensitisation to apoptosis was reversed by low concentrations (10(-13)-10(-10) M), but not by high concentrations (10(-9)-10(-7) M) of ET-1. These results suggest that the binding of ET-1 to high-affinity sites inhibits FasL-induced apoptosis, while the binding of either ET-1 or receptor antagonists to low-affinity sites promotes FasL-induced apoptosis. In conclusion, endothelin signalling pathways do not induce human colon cancer cell proliferation, but are survival signals controling resistance to apoptosis

Increased endothelin-1 in colorectal cancer and reduction of tumour growth by ET A receptor antagonism

Endothelin-1 (ET-1) is a vasoconstrictor peptide which stimulates proliferation in vitro in different cell types, including colorectal cancer cells. Raised ET-1 levels have been detected both on tissue specimens and in the plasma of patients with cancers. To investigate the role of ET-1 in colorectal cancer: (i) ET-1 plasma levels in patients with colorectal cancer were measured by radioimmunoassay: group 1 = controls (n = 22), group 2 = primary colorectal cancer only (n = 39), group 3 = liver metastases only (n = 26); (ii) ET-1 expression in primary colorectal cancer specimens (n =10) was determined immunohistochemically and (iii) the effect of intraportally infused antagonists to the two ET-1 receptors, ET A and ET B, on the growth of liver metastases in a rat model was assessed. ET-1 plasma levels were significantly increased in both patients with primary tumour and patients with metastases, compared to controls (P < 0.01, 3.9 ± 1.4, 4.5 ± 1.5, vs. 2.75 ± 1.37 pg/ml, respectively). Immunohistochemically, strong expression of ET-1 was found in the cytoplasm, stroma and blood vessels of cancers, unlike the normal colon where only the apical layer of the epithelium, vascular endothelial cells and surrounding stroma were positively stained. In the rat model, there was significant reduction in liver tumour weights compared to controls, following treatment with the ET A antagonist (BQ123) 30 min after the intraportal inoculation of tumour cells (P < 0.05). These results suggest ET-1 is produced by colorectal cancers and may play a role in the growth of colorectal cancer acting through ET A receptors. ET A antagonists are indicated as potential anti-cancer agents. © 2001 Cancer Research Campaign http://www.bjcancer.co

Endothelin-1 enhances fibrogenic gene expression, but does not promote DNA synthesis or apoptosis in hepatic stellate cells

BACKGROUND: In liver injury, the pool of hepatic stellate cell (HSC) increases and produces extracellular matrix proteins, decreasing during the resolution of fibrosis. The profibrogenic role of endothelin-1 (ET-1) in liver fibrosis remains disputed. We therefore studied the effect of ET-1 on proliferation, apoptosis and profibrogenic gene expression of HSCs. RESULTS: First passage HSC predominantly expressed endothelin A receptor (ETAR) mRNA and 4th passage HSC predominantly expressed the endothelin B receptor (ETBR) mRNA. ET-1 had no effect on DNA synthesis in 1st passage HSC, but reduced DNA synthesis in 4th passage HSC by more than 50%. Inhibition of proliferation by endothelin-1 was abrogated by ETBR specific antagonist BQ788, indicating a prominent role of ETBR in growth inhibition. ET-1 did not prevent apoptosis induced by serum deprivation or Fas ligand in 1st or 4th passage HSC. However, ET-1 increased procollagen α1(I), transforming growth factor β-1 and matrix metalloproteinase (MMP)-2 mRNA transcripts in a concentration-dependent manner in 1st, but not in 4th passage HSC. Profibrogenic gene expression was abrogated by ETAR antagonist BQ123. Both BQ123 and BQ788 attenuated the increase of MMP-2 expression by ET-1. CONCLUSION: We show that ET-1 stimulates fibrogenic gene expression for 1st passage HSC and it inhibits HSC proliferation for 4th passage HSC. These data indicate the profibrogenic and antifibrogenic action of ET-1 for HSC are involved in the process of liver fibrosis

Symptomatic cerebral oedema during treatment of diabetic ketoacidosis: effect of adjuvant octreotide infusion

<p>Abstract</p> <p>Introduction</p> <p>A potentially lethal complication of diabetic ketoacidosis (DKA) in children is brain oedema, whether caused by DKA itself or by the therapeutic infusion of insulin and fluids.</p> <p>Case presentation</p> <p>A 10-year old previously healthy boy with DKA became unconscious and apnoeic due to cerebral oedema (confirmed by abnormal EEG and CT-scan) during treatment with intravenous fluids (36 ml/h) and insulin (0.1 units/kg/h). He was intubated and artificially ventilated, without impact on EEG and CT-scan. Subsequently, adjuvant infusion of octreotide was applied (3.5 μg/kg/h), suppressing growth hormone (GH) and IGF-1 production and necessitating the insulin dose to be reduced to 0.05 - 0.025 units/kg/h. The brain oedema improved and the boy made a full recovery.</p> <p>Conclusion</p> <p>Co-therapy with octreotide was associated with a favourable outcome in the present patient with DKA and cerebral oedema. Whether this could be ascribed to the effects of octreotide on the insulin requirement or on the GH/IGF-axis remains to be elucidated.</p

Clinical characteristics of patients with type 2 diabetes mellitus at the time of insulin initiation: INSTIGATE observational study in Spain

Little information is available on the management of patients with type 2 diabetes mellitus (DM2) in regular clinical practice, prior to and at the point of initiating treatment with insulin. The INSTIGATE study provides a description of the clinical profile of the patient with DM2 who begins treatment with insulin in both primary and secondary care. A total of 224 patients who had been diagnosed with DM2, were not responding to oral treatment, and began receiving insulin were included in the INSTIGATE study in Spain. Demographic data were collected, as well as data on macro- and microvascular complications of diabetes and comorbidities, past medical history of diabetes and oral treatment administered, the clinical severity of diabetes (HbA1c concentration) and insulin treatment initiated. Mean age of the sample was 65.4 years and 56.7% were men. There were 87% of patients who had a diagnosis of at least one significant comorbidity, notably hypertension and hyperlipidemia. The patient profile for metabolic syndrome was met by 75.1% of the patients. There was a higher incidence of macrovascular complications (38.4%) than microvascular complications (16.1%). Prior to insulin initiation, the most recent mean HbA1c was 9.2%. The majority of patients had been treated in the last 12 months with sulfonylureas and/or metformin (69.6 and 57.6%). The most common treatment prior to insulinization was the co-administration of two oral antidiabetics (OADs) (37.5%). Patients with DM2 observed in the study presented with elevated mean HbA1c and body mass index levels, comorbidities and complications related to diabetes at the time of insulin initiation. Changes and adjustments in treatment from diagnosis of diabetes occur when HbA1c levels are far above those recommended by the IDF (International Diabetes Federation), a factor which could be contributing to the development of both macrovascular and microvascular complications in the patient profile described in the study

Basal plus basal-bolus approach in type 2 diabetes

This is a copy of an article published in the Diabetes Technology and Therapeutics © 2011 [copyright Mary Ann Liebert, Inc.]; Diabetes Technology and Therapeutics is available online at: http://online.liebertpub.com.[EN] Type 2 diabetes is characterized by insulin resistance and progressive b-cell deterioration. As b-cell function declines, most patients with type 2 diabetes treated with oral agents, in monotherapy or combination, will require insulin therapy. Addition of basal insulin (glargine, detemir, or NPH/neutral protamine lispro insulin) to previous treatment is accepted as the simplest way to start insulin therapy in those patients. But even when basal insulin is adequately titrated, some patients will also need prandial insulin to achieve or maintain individual glycemic targets over time. Starting with premixed insulin is an effective option, but it is frequently associated with increased hypoglycemia risk, ¿xed meal schedules, and weight gain. As an alternative, a novel approached known as ``basal plus strategy¿¿ has been developed. This approach considers the addition of increasing injections of prandial insulin, beginning with the meal that has the major impact on postprandial glucose values. Finally, if this is not enough intensi¿cation to basal¿bolus will be necessary. In reducing hyperglycemia, this modality still remains the most effective option, even in people with type 2 diabetes. This article will review the currently evidence on the basal plus strategy and also its progression to basal¿bolus therapy. In addition, practical recommendations to start and adjust basal plus therapy will be provided.F.J.A.-B. has received honoraria as speaker and/or consultant from Abbott, AstraZeneca, Bristol-Myers Squibb, Glaxo-SmithKline, LifeScan, Lilly, Madaus, MannKind Corp., Medtronic, Menarini, Merch Farma y Quimica, SA, MSD, Novartis, Novo Nordisk, Pfizer, Roche, sanofi-aventis, Schering-Plough, and Solvay. In addition, F.J.A.-B. has participated in clinical trials supported totally or partially by AstraZeneca, Glaxo-SmithKline, LifeScan, Lilly, MSD, Novo Nordisk, Pfizer, sanofi-aventis, and Servier. P. R. has no potential conflicts of interest to declare. J.F.A. has received honoraria as speaker and/or consultant form AstraZeneca, Ferrer, Glaxo-SmithKline, Laboratorios Dr. Esteve, Lilly, MSD, and Solvay.Ampudia-Blasco, J.; Rossetti ., P.; Ascaso, JF. (2011). Basal plus basal-bolus approach in type 2 diabetes. Diabetes Technology & Therapeutics. 13:75-83. doi:10.1089/dia.2011.0001S75831