EGF and β1 Integrin Convergently Regulate Migration of A431 Carcinoma

金沢大学大学院医学系研究科We found that the convergently epidermal growth factor (EGF)-induced signal and the collagen-induced signal activate mitogen-activated protein kinase (MAPK), which induces migration. We examined the signaling mechanisms of EGF-induced cell migration on collagen using the A431 carcinoma cell. EGF (10 ng/ml) induced migration on collagen, but inhibited proliferation. Using a MAPK cascade inhibitor, PD98059, it was shown that EGF-induced migration on collagen was mediated by MAPK whereas EGF-induced migration on fibronectin and vitronectin was not. PD98059 also showed that activation of MAPK induced by EGF enhanced the adhesiveness of A431 cells to collagen. By Western blotting analysis, the kinetics of MAPK phosphorylation induced by EGF and collagen was examined separately, and convergently. First of all, EGF without collagen caused transient MAPK phosphorylation. Collagen without EGF caused MAPK to be immediately and transiently dephosphorylated, and rephosphorylated followed by sustained hyperphosphorylation. EGF together with collagen caused an immediate, and sustained, hyperphosphorylation. These facts suggest that the transient MAPK dephosphorylation induced by collagen is required for migration in order to maintain an appropriate level of sustained phosphorylation. Furthermore, we found that adhesion of A431 cells to collagen was blocked by the anti-β1 integrin antibody or by the mixed antibodies composed of anti-α1, -α2, and -α3 antibodies, indicating that collagen-induced MAPK phosphorylation was mediated through α1β1, α2β1, and α3β1 integrins. © 2002 Elsevier Science

Cardioprotective effects of low-dose combination therapy with a statin and an angiotensin receptor blocker in a rat myocardial infarction model

SummaryPurposeStatins attenuate angiotensin II-induced myocyte hypertrophy and this might increase the cardioprotective effects of renin–angiotensin system inhibition in the ischemic heart. In this study, we investigated the cardioprotective effects of combination therapy with low-dose simvastatin and low-dose losartan using a rat myocardial infarction model.MethodsMyocardial infarction was created in rats by left anterior descending artery ligation, and the animals were randomly allocated to one of four groups: control (n=8), losartan 3mg/kg/day (n=8), simvastatin 2mg/kg/day (n=8), and losartan 3mg/kg/day plus simvastatin 2mg/kg/day (n=8). Each treatment was started on the day of coronary ligation, and hemodynamics, myocardial blood flow, and infarct size were measured after 28 days.ResultsBlood pressure, heart rate, and left ventricular systolic and end-diastolic pressures were not significantly different comparing the control group with the 3 other treatment groups. The peak positive first derivative of left ventricular pressure (peak LV dP/dt) was equivalent comparing the control group with the losartan and simvastatin groups. However, the peak LV dP/dt was greater in the losartan plus simvastatin group than in the control group (p<0.05). Myocardial blood flow, left ventricular weight, and infarct size were not significantly altered by the 3 treatments.ConclusionsTreatment with 3mg/kg/day losartan plus 2mg/kg/day simvastatin but not losartan or simvastatin alone improved left ventricular systolic function in a rat myocardial infarction model. The result suggests that statins given in combination with angiotensin receptor blockers might have beneficial cardioprotective effects, even at low-doses for each agent

A prospective multicenter study on genome wide associations to ranibizumab treatment outcome for age-related macular degeneration

We conducted a genome-wide association study (GWAS) on the outcome of anti-VEGF treatment for exudative age-related macular degeneration (AMD) in a prospective cohort. Four hundred and sixty-one treatment-naïve AMD patients were recruited at 13 clinical centers and all patients were treated with 3 monthly injections of ranibizumab followed by pro re nata regimen treatment for one year. Genomic DNA was collected from all patients for a 2-stage GWAS on achieving dry macula after the initial treatment, the requirement for an additional treatment, and visual acuity changes during the 12-month observation period. In addition, we evaluated 9 single-nucleotide polymorphisms (SNPs) in 8 previously reported AMD-related genes for their associations with treatment outcome. The discovery stage with 256 patients evaluated 8, 480, 849 SNPs, but no SNPs showed genome-wide level significance in association with treatment outcomes. Although SNPs with P-values of <5 × 10[−6] were evaluated in replication samples of 205 patients, no SNP was significantly associated with treatment outcomes. Among AMD-susceptibility genes, rs10490924 in ARMS2/HTRA1 was significantly associated with additional treatment requirement in the discovery stage (P = 0.0023), and pooled analysis with the replication stage further confirmed this association (P = 0.0013). ARMS2/HTRA1 polymorphism might be able to predict the frequency of injection after initial ranibizumab treatment