24-Hour ambulatory blood pressure control with triple-therapy amlodipine, valsartan and hydrochlorothiazide in patients with moderate to severe hypertension.

To determine the effectiveness and safety of once-daily combination therapy with amlodipine, valsartan and hydrochlorothiazide for reducing ambulatory blood pressure (ABP) in patients with moderate to severe hypertension, a multicenter, double-blind study was performed (N=2271) that included ABP monitoring in a 283-patient subset. After a single-blind, placebo run-in period, patients were randomized to receive amlodipine/valsartan/hydrochlorothiazide (10/320/25 mg), valsartan/hydrochlorothiazide (320/25 mg), amlodipine/valsartan (10/320 mg) or amlodipine/hydrochlorothiazide (10/25 mg) each morning for 8 weeks. Efficacy assessments included change from baseline in 24-h, daytime and night time mean ambulatory systolic BP (SBP) and diastolic BP (DBP). Statistically significant and clinically relevant reductions from baseline in all these parameters occurred in all treatment groups (P<0.0001, all comparisons versus baseline). At week 8, least squares mean reductions from baseline in 24-h, daytime and night time mean ambulatory SBP/DBP were 30.3/19.7, 31.2/20.5 and 28.0/17.8 mm Hg, respectively, with amlodipine/valsartan/hydrochlorothiazide; corresponding reductions with dual therapies ranged from 18.8-24.1/11.7-15.5, 19.0-25.1/12.0-16.0 and 18.3-22.6/11.1-14.3 mm Hg (P≤0.01, all comparisons of triple versus dual therapy). Treatment with amlodipine/valsartan/hydrochlorothiazide maintained full 24-h effectiveness, including during the morning hours; all hourly mean ambulatory SBP and mean ambulatory DBP measurements were ≤130/85 mm Hg at end point. Amlodipine/valsartan/hydrochlorothiazide combination therapy was well tolerated. Once-daily treatment with amlodipine/valsartan/hydrochlorothiazide (10/320/25 mg) reduces ABP to a significantly greater extent than component-based dual therapy and maintains its effectiveness over the entire 24-h dosing period.

Combination therapy with amlodipine/valsartan in essential hypertension: a 52-week, randomised, open-label, extension study.

BACKGROUND: A majority of hypertensive patients require > or = 2 agents to achieve target blood pressure (BP). METHODS: This 52-week, multicentre, open-label, randomised extension trial to a previously reported double-blind, placebo-controlled study evaluated the safety and efficacy of amlodipine/valsartan (Aml/Val) combination. Patients who successfully completed the core study without serious drug-related adverse events (AEs) and mean sitting systolic BP (MSSBP)/mean sitting diastolic BP (MSDBP) < or = 150/95 mmHg were eligible to enter the extension and be treated with Aml/Val 2.5/80 or 5/80 mg. After 4 weeks of treatment, patients underwent force-titration to receive 5/160 mg (low dose) or 10/160 mg (high dose) for 48 weeks. Addition of hydrochlorothiazide (HCTZ) 12.5 mg was permitted if BP was > or = 140/90 mmHg at Week 8 or later. Patients could be down-titrated to the prior lower combination dose with or without HCTZ if an intolerable AE occurred. Safety evaluations included monitoring of AEs. Efficacy variables were change from baseline in MSDBP (primary) and MSSBP (secondary). RESULTS: Of 1246 patients randomised, 1075 (86.3%) completed the extension study. At week 52 end-point, change in MSSBP/MSDBP from core study baseline was -22.1/-17.2 mmHg for low-dose regimen and -22.8/-18.1 mmHg for high-dose regimen. For both regimens, reductions in BP were sustained over 52 weeks and mean BP maintained below approximately 135/85 mmHg at all visits. Frequent AEs in the low- and high-dose regimens were peripheral oedema (9.7% and 17.1% respectively), nasopharyngitis (8.1% and 7.2%), and dizziness (5.2% and 7.0%). Incidence of serious AEs was 3.7% with low dose and 4.1% with high dose. CONCLUSION: The combination of Aml/Val with the optional addition of HCTZ produced clinically significant and persistent reductions in BP over 52 weeks with a favourable tolerability profile.

Achieving blood pressure goal: initial therapy with valsartan/hydrochlorothiazide combination compared with monotherapy.

The benefits of valsartan (Val)/hydrochlorothiazide (HCTZ) combination as initial treatment for hypertension were evaluated in a post hoc analysis of an 8-week, double-blind, placebo-controlled, parallel-group trial. The highest dose of Val/HCTZ combination (320/25 mg), component monotherapies (Val 320 mg, HCTZ 25 mg) and placebo were selected for this analysis (N=675, 52.1% men, 68.6% Caucasians, mean age 52.9 years, baseline blood pressure (BP) 150.6/99.1 mm Hg). As soon as 2 weeks after initiation of active therapy, greater BP control rates were observed with Val/HCTZ (320/25 mg) compared with Val (320 mg), HCTZ (25 mg) and placebo. Similar results were observed in subgroups of patients with stage 1 and stage 2 hypertension, as well as in diabetic patients. As baseline BP increased, the probability of achieving mean sitting systolic BP (<140 and <130 mm Hg) and mean sitting diastolic BP control (<90 and <80 mm Hg), determined using a logistic regression model, decreased with all treatments. However, at all levels of baseline BP, the probability of achieving BP control was greater with Val/HCTZ combination. The Val/HCTZ combination was well tolerated with overall incidence of adverse events similar to that observed with monotherapy and placebo. These results support the use of Val/HCTZ combination as initial therapy in hypertensive patients unlikely to achieve BP control with a single agent.

Efficacy and tolerability of amlodipine/valsartan combination therapy in hypertensive patients not adequately controlled on amlodipine monotherapy.

UNLABELLED: ABSTRACT (ARB), in essential hypertensive patients not adequately controlled by amlodipine monotherapy. METHODS: This was a multi-centre, randomised, double-blind, active-controlled study in patients with essential hypertension. After a washout period followed by a single-blind amlodipine 10 mg run-in period, patients with mean sitting diastolic blood pressure (msDBP) > or =90 mmHg and <110 mmHg were randomised to receive amlodipine/valsartan (10/160 mg o.d.) or amlodipine (10 mg o.d.) for 8 weeks. TRIAL REGISTRATION NUMBER: NCT00171002. MAIN OUTCOME MEASURES: The primary efficacy variable was change from baseline in msDBP at study endpoint. Secondary efficacy variables were change from baseline in mean sitting systolic blood pressure (msSBP), responder rate (msDBP <90 mmHg or > or =10 mmHg reduction from baseline) and DBP control rate (msDBP <90 mmHg). RESULTS: Of the 1283 patients enrolled in single-blind period, 944 were randomised to receive amlodipine/valsartan 10/160 mg (n = 473) and amlodipine 10 mg (n = 471). Statistically significant greater reductions (p < 0.0001) from baseline in msSBP/msDBP were observed with combination therapy (12.9/11.4 mmHg) compared to monotherapy (10.0/9.3 mmHg). Responder rate was significantly greater (p = 0.0011) with combination therapy (79.0%) compared to monotherapy (70.1%). The percentage of patients with controlled DBP was also significantly (p < 0.0001) higher with combination therapy (77.8%) compared to monotherapy (66.5%). Incidence of peripheral oedema was slightly higher with amlodipine monotherapy (9.4%) compared to combination therapy (7.6%). CONCLUSION: The combination of amlodipine/valsartan in this 8-week double-blind study provided additional BP control and was well tolerated in patients inadequately controlled with amlodipine monotherapy. Results should be interpreted with the knowledge that study entry criteria may limit application to a wider population.

Efficacy and tolerability of amlodipine/valsartan combination therapy in hypertensive patients not adequately controlled on valsartan monotherapy.

OBJECTIVE: To demonstrate additional BP-lowering effects of amlodipine/valsartan combination in patients whose BP was not adequately controlled on valsartan alone. METHODS: This was a multi-centre, randomised, double-blind, active-controlled study in patients with essential hypertension. After a washout period followed by a single-blind valsartan 160 mg run-in period, patients with mean sitting diastolic blood pressure (DBP) >or= 90 mmHg and < 110 mmHg were randomised to receive amlodipine/valsartan (10/160 mg or 5/160 mg o.d.) or valsartan (160 mg o.d.) for 8 weeks. TRIAL REGISTRATION: NCT00170963 MAIN OUTCOME MEASURES: Primary efficacy variable was change from baseline in mean DBP at study end. Secondary efficacy variables included change from baseline in mean sitting systolic blood pressure (SBP), responder rate (mean DBP < 90 mmHg or >or= 10 mmHg reduction from baseline), and DBP control rate (mean DBP < 90 mmHg). Safety was also assessed. RESULTS: Of 1136 patients enrolled in single-blind phase, 947 (mean age: 54.6 years) were randomised. Statistically significantly greater reductions in mean SBP/DBP were observed in both amlodipine/valsartan combinations (10/160 mg: 14.3/11.5 mmHg, 5/160 mg: 12.2/9.6 mmHg; both p < 0.0001) compared to valsartan 160 mg (8.3/6.7 mmHg). The 10/160 mg combination (p < 0.05) showed statistically significantly greater reductions in mean SBP/DBP compared to 5/160 mg (p < 0.001). Responder rates were higher in both combination therapy groups (10/160 mg: 81% [p < 0.0001]; 5/160 mg: 68% [p = 0.0018], respectively) compared to monotherapy (57%). Peripheral oedema was the most frequent adverse event, reported in amlodipine/valsartan 10/160 mg (9.1%), 5/160 mg (0.9%), and valsartan 160 mg (1.3%). CONCLUSIONS: The combination of amlodipine/valsartan in this 8-week double-blind study provided additional BP control and was well-tolerated in patients inadequately controlled with valsartan monotherapy.

Assessing crystallization droplets using birefringence.

In this paper, the detection of crystalline elements in protein crystallization droplets containing precipitate is illustrated using the rotating-polarizer microscope technique. The sensitivity of this automated birefringence technique enables the detection of microcrystals in a precipitate that appears to be amorphous using traditional methods of inspection. The technique is illustrated with lysozyme and glucose isomerase. Glucose isomerase microcrystals were used successfully for seeding experiments and the conditions of both of the systems were refined to produce crystals suitable for X-ray analysis. The results are relevant to the field of high-throughput crystallography as an automated crystal-detection method as well as being a useful tool for detailed precipitate analysis.

Akt1 induces extracellular matrix invasion and matrix metalloproteinase-2 activity in mouse mammary epithelial cells.

The roles of the protein-serine/threonine kinase, Akt1, in signaling pathways associated with cell motility and extracellular matrix invasion were examined in the immortalized mouse mammary epithelial cell line, COMMA-1D. COMMA-1D cells were engineered to express the avian leukosis subtype A receptor, tv-a, to permit infection by recombinant avian leukosis virus produced by the replication-competent avian splice vector, RCAS. COMMA-1D/tv-a cells transduced with RCAS/v-akt, but not RCAS/Akt1, formed anchorage-independent colonies in soft agar; however, cells overexpressing either v-akt or Akt1 became highly invasive when grown on the ECM, Matrigel. Zymography of extracellular protease activity shed into the medium by COMMA-1D/Akt1 or COMMA-1D/v-akt cells revealed elevated gelatinase activity that was confirmed to be matrix metalloproteinase-2 (MMP-2; gelatinase A) by Western blotting and immunoprecipitation-zymography. The MMP inhibitor, BB-94, blocked MMP-2 activity and invasion associated with Akt1- and v-akt-expressing cells. The proteasome inhibitor, lactacystin, markedly increased MMP-2 levels and invasion in control cells but not in Akt1- and v-akt-expressing cells. These results suggest that the invasive behavior of mammary epithelial cells induced by Akt1 is associated with increased MMP-2 expression that may result from inhibition of MMP-2 degradation by the proteasome pathway.

Once-daily treatment of patients with hypertension: a placebo-controlled study of amlodipine and benazepril vs amlodipine or benazepril alone.

OBJECTIVE: To compare the efficacy, tolerability, and safety of once-daily therapy with amlodipine 5 mg/benazepril 10 mg vs amlodipine 5 mg, benazepril 10 mg, and placebo. DESIGN: Randomised, double-blind, placebo-controlled, parallel-group, multicentre trial. SETTING: Twenty-two clinical centres, including private practice groups and academic research clinics. PATIENTS: A total of 530 patients between 21 and 80 years of age with essential hypertension were screened for the study, and 454 were randomised to treatment with amlodipine 5 mg/benazepril 10 mg, amlodipine 5 mg, benazepril 10 mg, or placebo for 8 weeks. RESULTS: Amlodipine 5 mg/benazepril 10 mg produced greater reductions from baseline in sitting diastolic blood pressure than amlodipine 5 mg (P < 0.03), benazepril 10 mg (P < 0.001), and placebo (P < 0.001). The response rate in the amlodipine 5-mg/benazepril 10-mg treatment group (66.4%) was better than that observed in the amlodipine 5-mg (50.0% P < 0.02), benazepril 10-mg (38.3% P < 0.001), and placebo (24.4% P < 0.001) groups. There was no significant difference in heart rate among the four groups. The incidence of oedema in the amlodipine 5-mg/benazepril 10-mg (1.7%) group was somewhat less than that in the amlodipine 5-mg (4.5%) group. CONCLUSIONS: Therapy with amlodipine 5 mg/benazepril 10 mg was well tolerated and was superior to amlodipine 5 mg, benazepril 10 mg, and placebo in reducing sitting diastolic blood pressure in patients with essential hypertension.

Detection of a mixed-backbone oligonucleotide (GEM 231) in liver and tumor tissues by capillary electrophoresis.

A simple, rapid and sensitive method has been developed and validated for the analysis of a mixed-backbone oligonucleotide (GEM 231) in tumor tissues. The analysis was performed using a capillary electrophoresis (CE) system with UV detection. An extended light path (bubble cell) capillary column of 64.5 cm (effective length 56 cm) x 50 microm I.D. is used as the separation column. The optimized chromatographic conditions were background electrolyte: sodium borate buffer (60 mM, pH 9.1), electrokinetic injection: 10 s, applied voltage: 30 kV, detection at lambda = 210 nm. A linear relationship was observed between the peak area and the amount of GEM 231 in the range of 1.0-1000 microg/ml. The lower detection limit of the drug was 100 pg with an average recovery of about 75 +/- 5%. The inter-day and intra-day relative standard deviations were <10%. Assay validation studies revealed that CE method is reproducible and specific for the determination of GEM 231 in tissue homogenates with a run time of less than 5 min.

Baseline demographics of the Valsartan Heart Failure Trial. Val-HeFT Investigators.

BACKGROUND: The Valsartan Heart Failure Trial (Val-HeFT) is the first large-scale randomized, multinational clinical study to assess the efficacy and safety of valsartan, an angiotensin II receptor blocker, added to conventional therapy, including angiotensin-converting enzyme inhibitors, in heart failure patients. A total of 5010 patients with an ejection fraction <40% have been randomized to either valsartan titrated to 160 mg b.i.d. or to placebo. AIMS: Baseline characteristics of patients in Val-HeFT are presented and compared with other major clinical trials in heart failure. METHODS: Baseline data were collected and summary statistics calculated. RESULTS: The study population has a mean age of 62.7 years and is 80% male, 90.3% white, 6.9% black, and 2.8% Asian. Antecedent coronary heart disease is reported in 57.2% of patients. Angiotensin-converting enzyme inhibitors are prescribed for 92.7% of patients, diuretics for 85.8%, digoxin for 67.3%, and beta-blockers for 35.6%. Subgroup comparisons by age, sex, race and ejection fraction quartile show small differences in baseline characteristics. CONCLUSION: Overall the Val-HeFT population is generally representative of the population of patients with mild to moderate heart failure in industrialized countries.

An invasion-related complex of cortactin, paxillin and PKCmu associates with invadopodia at sites of extracellular matrix degradation.

Invasive breast cancer cells have the ability to extend membrane protrusions, invadopodia, into the extracellular matrix (ECM). These structures are associated with sites of active matrix degradation. The amount of matrix degradation associated with the activity of these membrane protrusions has been shown to directly correlate with invasive potential. We demonstrate here that microinjection of polyclonal anti-cortactin antibodies blocks matrix degradation at invadopodia supporting the hypothesis that cortactin has a direct role in invasive behavior. MDA-MB-231, invasive breast cancer cells were sheared from the surface of a gelatin matrix to isolate invadopodia. Cortactin, paxillin and protein kinase C (PKC) mu, a serine kinase, were co-immunoprecipitated as a complex from invadopodia-enriched membranes. We confirmed the subcellular distribution of these proteins by immunolocalization and Western blotting. We also determined that, in contrast to its presence in invasive cells, this complex of proteins was not detected in lysates from non-invasive cells that do not form invadopodia. Taken together, these data suggest that the formation of this cortactin-containing complex correlates with cellular invasiveness. We hypothesize that this complex of molecules has a role in the formation and function of invadopodia during cellular invasion.

Role of AKT1 in 17beta-estradiol- and insulin-like growth factor I (IGF-I)-dependent proliferation and prevention of apoptosis in MCF-7 breast carcinoma cells.

AKT1 (c-AKT, PKBalpha) is the cellular homolog of the protein-serine/threonine kinase oncogene, v-akt. AKT1 is activated through the insulin and platelet-derived growth factor signaling pathways in transfected fibroblasts, but little is known about the regulation of endogenous AKT1 in tumor cells. AKT1 levels were higher in a panel of human breast carcinoma cell lines than in breast epithelial cells, particularly those with higher HER2 expression. AKT1 activity was increased by either estradiol or IGF-I in estrogen-dependent MCF-7 cells, and both factors acted synergistically to increase AKT1 activity and promote cell proliferation. Stimulation of AKT1 activity by estradiol and IGF-I was blocked by the antiestrogen ICI 182780 and by the phosphatidylinositol-3-kinase inhibitor wortmannin. MCF-7 cells transfected with AKT1 exhibited partial estrogen- and IGF-I-independent growth and were more responsive to the combination of IGF-I and estradiol. AKT1-overexpressing MCF-7 cells were less sensitive to apoptosis induced by wortmannin. These findings suggest that AKT1 is a downstream effector of estrogen- and IGF-I-dependent proliferation and survival in hormone-responsive MCF-7 breast carcinoma cells.

Rationale and design of the Valsartan Heart Failure Trial: a large multinational trial to assess the effects of valsartan, an angiotensin-receptor blocker, on morbidity and mortality in chronic congestive heart failure.

BACKGROUND: To investigate the role of persistent angiotensin activity despite angiotensin-converting enzyme inhibitor therapy in the progression of heart failure, the Valsartan Heart Failure Trial has been designed to investigate the effect of the angiotensin-receptor blocker, valsartan, on morbidity and mortality. METHODS AND RESULTS: Nearly 5,000 patients with New York Heart Association classes II to IV heart failure, while receiving all standard therapy, are being randomized to treatment with valsartan, 160 mg twice daily, or placebo in a worldwide study. Follow-up will be continued until 906 deaths have been recorded. Additional end points will include the need for hospitalization, other major morbid events, quality--of life measurement, changes in neurohormone levels, and changes in left ventricular size and function. Substudies will explore exercise tolerance, arrhythmias, and magnetic resonance imaging. CONCLUSION: This study should help establish the role of angiotensin-receptor blockade in the treatment of heart failure.

Dose-response efficacy of valsartan, a new angiotensin II receptor blocker.

OBJECTIVE: To study the efficacy and tolerability of a range of valsartan doses in patients with mild-to-moderate hypertension. DESIGN: 122 adult out-patients were randomised in equal numbers to receive valsartan 10 mg, 40 mg, 80 mg, 160 mg or placebo once daily (OD) for 4 weeks in this multicentre, double-blind, fixed-dose, parallel trial. Patients were assessed at 0, 2 and 4 weeks. MAIN OUTCOME MEASURES: The primary efficacy variable was change from baseline in trough mean supine diastolic blood pressure (MSuDBP). Other variables included change from baseline in trough mean supine systolic blood pressure (MSuSBP), responder rates and trough/peak ratio. RESULTS: All treatments significantly reduced MSuDBP and MSuSBP at 4-week end-point compared to baseline (P < 0.001). The magnitude of blood pressure lowering was greater with increasing doses of valsartan (least square mean change from baseline for placebo, valsartan 10 mg, 40 mg, 80 mg, 160 mg respectively: MSuDBP -4.4 mm Hg, -4.9 mm Hg, -6.5 mm Hg, -8.2 mm Hg, -9.1 mm Hg; MSuSBP -1.3 mm Hg, -3.6 mm Hg, -7.0 mm Hg, -11.1 mm Hg, -11.9 mm Hg). A fitted quadratic curve, to predict relationship between dose and change from baseline in trough MSuDBP, indicated a positive dose response. Responder rates were 16%, 24%, 33%, 46%, 54% for placebo, valsartan 10 mg, 40 mg, 80 mg, 160 mg respectively, which also indicated a positive dose response in the dose range of 10 mg to 160 mg. Greater than 50% of the antihypertensive effect measured at peak persisted at trough for each of the four active treatment groups, confirming efficacy over a 24-h period. No dose-related adverse experiences were observed, with overall incidence (regardless of relationship to trial medication) of 44% with placebo and 44%, 36%, 22%, 21% for valsartan 10 mg, 40 mg, 80 mg, 160 mg respectively. The most common adverse experience reported was headache which occurred most frequently with placebo (12%). No trial drug-related cough was observed. Treatment with valsartan did not produce clinically significant orthostatic changes in diastolic or systolic blood pressure. One case of symptomatic orthostatic hypotension was observed on placebo. CONCLUSIONS: The results of this trial show valsartan to effectively lower blood pressure in patients with mild-to-moderate hypertension, and demonstrate that the reduction in blood pressure increases with increasing dose levels.

Induction of p53-dependent, insulin-like growth factor-binding protein-3-mediated apoptosis in glioblastoma multiforme cells by a protein kinase Calpha antisense oligonucleotide.

Protein kinase Calpha (PKCalpha) expression is related to tumor progression in glioblastoma multiforme (GBM), the most common malignant brain tumor in adults. To determine whether PKCalpha regulates an anti-apoptotic survival pathway in GBM, A172 GBM cells were treated with a PKCalpha-selective antisense oligonucleotide. PKCalpha antisense oligonucleotide treatment was accompanied by reduction in PKCalpha levels and the induction of wild-type p53 and insulin-like growth factor-binding protein-3 (IGFBP3) 24-72 h after treatment, a period that coincided with the appearance of apoptotic cell death as detected by DNA fragmentation. There were no significant changes in the levels of Bcl-XL, Bax, and p21(WAF1). Induction of p53 after PKCalpha down-regulation was not associated with increased mRNA expression, but increased IGFBP3 levels were accompanied by increased mRNA levels. Recombinant human IGFBP3 induced an apoptotic effect that was similar to the PKCalpha antisense oligonucleotide, and its effect was blocked by IGF-I. These results suggest that one mechanism by which PKCalpha produces its antiapoptotic activity in GBM cells is by suppressing the p53-mediated activation of IGFBP3.

Induction of apoptosis in glioblastoma cells by inhibition of protein kinase C and its association with the rapid accumulation of p53 and induction of the insulin-like growth factor-1-binding protein-3.

Increased protein kinase C(alpha) (PKC(alpha)) expression in glioblastoma cells is associated with proliferation and resistance to drug-induced apoptosis by an undefined anti-apoptotic pathway. To clarify the role of PKC in apoptosis, we have investigated the effect of the selective PKC inhibitor Ro 31-8220 (3-[1-[3-(amidinothio)propyl]-3-indolyl]-4-(1-methyl-3-indolyl)-1H -pyrrole-2,5-dione methanesulfonate) in two glioblastoma cell lines whose proliferation is dependent on high levels of PKC(alpha). U-87 and A172 cells treated with an IC50 of Ro 31-8220 exhibited nucleosomal DNA fragmentation that coincided with an increase in the number of apoptotic cells. This effect was preceded by the rapid nuclear accumulation of wild-type p53 within 2 hr, and an increased level of the pro-apoptotic protein, insulin-like growth factor-1-binding protein-3, (IGFBP3) but not other p53-regulated proteins such as p21WAF1 or Bax. Accumulation of p53 was also associated with the hypophosphorylated and activated form of the retinoblastoma tumor suppressor protein (RB) at later times after treatment. These results suggest that PKC(alpha) suppresses apoptosis in glioblastoma cells primarily by restricting the accumulation of p53 and the expression of insulin-like growth factor-1-binding protein, as well as by maintaining RB in an inactive hyperphosphorylated state.

Regulation of the MDR1 promoter by cyclic AMP-dependent protein kinase and transcription factor Sp1.

The expression of multidrug-resistance (MDR) in breast carcinoma cell line MCF-7/ADR50 is primarily dependent on the transcriptional activation of the MDR1 gene. We now report that MDR in this cell line is partially reversed by the type I cAMP-dependent protein kinase (PKA) inhibitor, 8-Cl-cAMP. MDR1 promoter activity was also regulated through a PKA-dependent pathway and was inhibited by 8-Cl-cAMP, and stimulated by the enantiomeric agonist, SpcAMP[S]. MDR1 promoter activity through an Sp1 response element was stimulated by exogenous Sp1, a factor that we have shown to be activated by PKA. These results indicate that MDR1 promoter activity is linked to the cAMP/PKA signaling pathway, and that PKA antagonists may be useful for reversing the multidrug-resistant phenotype.

Dose-responsive antihypertensive efficacy of valsartan, a new angiotensin II-receptor blocker.

Predictable dose-related efficacy is considered to be an important attribute of any antihypertensive agent. To determine the magnitude of dose-responsive efficacy for valsartan, a highly selective angiotensin II-receptor blocker, we conducted an integrated analysis of efficacy data from nine double-masked, randomized, placebo-controlled, parallel studies of similar design and of at least 4 weeks' duration. The intent-to-treat analysis included 4067 patients with mild-to-moderate hypertension who had received valsartan (n = 2901) 10, 20, 40, 80, 160, or 320 mg once daily or placebo (n = 1166). Blood pressure was assessed at trough (24 hours after the last dose). In all nine studies, valsartan doses > or = 80 mg produced statistically significant reductions in supine or seated diastolic blood pressure (SDBP) and systolic blood pressure (SSBP) compared with placebo (P < 0.05). The integrated analysis demonstrated a clear increase in blood-pressure-lowering efficacy with increasing dose across the range 10 to 320 mg (placebo-subtracted mean changes from baseline to end point for valsartan 10, 20, 40, 80, 160, and 320 mg, respectively: SDBP, -0.8, -2.8, -2.6, -3.9, -5.1, and -6.4 mm Hg; SSBP, -1.3, -5.7, -5.3, -6.8, -8.6, and -9.0 mm Hg). The data demonstrate that valsartan provides dose-responsive antihypertensive efficacy across the therapeutic dose range, with clinically relevant blood-pressure lowering at doses > or = 80 mg once daily.

The protein kinase ABC's of signal transduction as targets for drug development.

Signal transduction plays a key regulatory role in the growth and metastatic potential of tumor cells. These signaling pathways form an interconnecting grid that serves to regulate the homeostatic, survival and invasive functions of the cell. Among the key regulatory molecules in these pathways are the serine/threonine-protein kinases A, B, and C, also known respectively as cyclic AMP-dependent protein kinase (PKA), Akt (PKB) and protein kinase C (PKC). These protein kinases modulate pathways associated with tumor proliferation, cell survival and multidrug resistance, and at a molecule level are likely to serve as effective targets for drug design. The unique structural features of each protein kinase have been deduced from their crystallographic structures and form unique opportunities for structure-based drug design. In addition, these protein kinases are potentially important targets for antisense oligonucleotide therapy, and therefore may provide a means of selectively inhibiting tumor proliferation and inducing apoptosis with minimal nonspecific cytotoxicity.