Efficacy and Safety of Acoramidis in Transthyretin Amyloid Cardiomyopathy.

BACKGROUND: Transthyretin amyloid cardiomyopathy is characterized by the deposition of misfolded monomeric transthyretin (TTR) in the heart. Acoramidis is a high-affinity TTR stabilizer that acts to inhibit dissociation of tetrameric TTR and leads to more than 90% stabilization across the dosing interval as measured ex vivo. METHODS: In this phase 3, double-blind trial, we randomly assigned patients with transthyretin amyloid cardiomyopathy in a 2:1 ratio to receive acoramidis hydrochloride at a dose of 800 mg twice daily or matching placebo for 30 months. Efficacy was assessed in the patients who had an estimated glomerular filtration rate of at least 30 ml per minute per 1.73 m2 of body-surface area. The four-step primary hierarchical analysis included death from any cause, cardiovascular-related hospitalization, the change from baseline in the N-terminal pro-B-type natriuretic peptide (NT-proBNP) level, and the change from baseline in the 6-minute walk distance. We used the Finkelstein-Schoenfeld method to compare all potential pairs of patients within strata to generate a P value. Key secondary outcomes were death from any cause, the 6-minute walk distance, the score on the Kansas City Cardiomyopathy Questionnaire-Overall Summary, and the serum TTR level. RESULTS: A total of 632 patients underwent randomization. The primary analysis favored acoramidis over placebo (P<0.001); the corresponding win ratio was 1.8 (95% confidence interval [CI], 1.4 to 2.2), with 63.7% of pairwise comparisons favoring acoramidis and 35.9% favoring placebo. Together, death from any cause and cardiovascular-related hospitalization contributed more than half the wins and losses to the win ratio (58% of all pairwise comparisons); NT-proBNP pairwise comparisons yielded the highest ratio of wins to losses (23.3% vs. 7.0%). The overall incidence of adverse events was similar in the acoramidis group and the placebo group (98.1% and 97.6%, respectively); serious adverse events were reported in 54.6% and 64.9% of the patients. CONCLUSIONS: In patients with transthyretin amyloid cardiomyopathy, the receipt of acoramidis resulted in a significantly better four-step primary hierarchical outcome containing components of mortality, morbidity, and function than placebo. Adverse events were similar in the two groups. (Funded by BridgeBio Pharma; ATTRibute-CM ClinicalTrials.gov number, NCT03860935.).

Autosomal Dominant Hypocalcemia Type 1: A Systematic Review.

Autosomal dominant hypocalcemia type 1 (ADH1) is a rare form of hypoparathyroidism due to activating variants of the calcium-sensing receptor gene (CASR). Inherited or de novo activating variants of the CASR alter the set point for extracellular calcium, resulting in inadequate parathyroid hormone (PTH) secretion and inappropriate renal calcium excretion leading to hypocalcemia and hypercalciuria. Conventional therapy includes calcium and activated vitamin D, which can worsen hypercalciuria, resulting in renal complications. A systematic literature review, using published reports from 1994 to 2021, was conducted to catalog CASR variants, to define the ADH1 clinical spectrum, and to determine the effect of treatment on patients with ADH1. There were 113 unique CASR variants reported, with a general lack of genotype/phenotype correlation. Clinical data were available in 191 patients; 27% lacked symptoms, 32% had mild/moderate symptoms, and 41% had severe symptoms. Seizures, the most frequent clinical presentation, occurred in 39% of patients. In patients with blood and urine chemistries available at the time of diagnosis (n = 91), hypocalcemia (99%), hyperphosphatemia (59%), low PTH levels (57%), and hypercalciuria (34%) were observed. Blood calcium levels were significantly lower in patients with severe symptoms compared with asymptomatic patients (6.8 ± 0.7 versus 7.6 ± 0.7 mg/dL [mean ± SD]; p < 0.0001), and the age of presentation was significantly lower in severely symptomatic patients (9.1 ± 15.0 versus 19.3 ± 19.4 years; p < 0.01). Assessments for complications including nephrocalcinosis, nephrolithiasis, renal impairment, and brain calcifications in 57 patients on conventional therapy showed that 75% had at least one complication. Hypercalciuria was associated with nephrocalcinosis, nephrolithiasis, renal impairment, or brain calcifications (odds ratio [OR] = 9.3; 95% confidence interval [CI] 2.4-37.2; p < 0.01). In 27 patients with urine calcium measures before and after starting conventional therapy, the incidence of hypercalciuria increased by 91% (p < 0.05) after therapy initiation. ADH1 is a condition often associated with severe symptomatology at presentation with an increase in the risk of renal complications after initiation of conventional therapy. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

First-in-Human Study of AG10, a Novel, Oral, Specific, Selective, and Potent Transthyretin Stabilizer for the Treatment of Transthyretin Amyloidosis: A Phase 1 Safety, Tolerability, Pharmacokinetic, and Pharmacodynamic Study in Healthy Adult Volunteers.

AG10 is a novel, potent, and selective oral transthyretin (TTR) stabilizer being developed to treat TTR amyloidosis (ATTR). This randomized, double-blind, placebo-controlled study evaluated safety, tolerability, pharmacokinetics, and pharmacodynamics (ex vivo stabilization) of orally administered AG10 in healthy adult volunteers. Both mutant and wild-type ATTR are underdiagnosed diseases with limited therapeutic options. As TTR amyloidogenesis is initiated by dissociation of TTR tetramers destabilized due to inherited mutations or aging, AG10 is designed to treat the disease at its source. Four single and three multiple ascending dose levels of AG10 or matching placebo were orally administered. Safety and tolerability were assessed by vital signs, electrocardiogram, adverse events, and clinical laboratory tests. Pharmacokinetics were measured using a validated bioanalytical assay. Pharmacodynamics were assessed via three pharmacodynamic assays of TTR stabilization. AG10 was uniformly well tolerated, and no safety signals of clinical concern were observed. Pharmacokinetic observations included time to maximum concentration <1 hour, dose-dependent maximum concentration and area under the plasma concentration-time curve, low intersubject variability, and half-life ∼25 hr. Complete (>90%) stabilization of TTR was observed across the entire dosing interval at steady state on the highest dose tested. Serum TTR levels, an in vivo reflection of TTR stabilization by AG10, increased from baseline following 12 days of dosing. AG10 appears to be safe and well tolerated in healthy adult volunteers and can completely stabilize TTR across the dosing interval, establishing clinical proof of concept. Based on these data, AG10 has the potential to be a safe and effective treatment for patients with either mutant or wild-type ATTR.

Transthyretin Stabilization by AG10 in Symptomatic Transthyretin Amyloid Cardiomyopathy.

BACKGROUND: Transthyretin (TTR) amyloidosis is an underdiagnosed disease caused by destabilization of TTR due to pathogenic mutations or aging. Both pathogenic and protective mutations illuminate mechanisms of disease and potential interventions. AG10 is a selective, oral TTR stabilizer under development for transthyretin amyloidosis cardiomyopathy (ATTR-CM) that mimics a protective TTR mutation. OBJECTIVES: This randomized, double-blind, placebo-controlled study evaluated safety, tolerability, pharmacokinetics, and pharmacodynamics of AG10 in ATTR-CM patients with symptomatic, chronic heart failure. METHODS: ATTR-CM, New York Heart Association functional class II to III subjects (n = 49, mutant or wild-type) were randomized 1:1:1 to AG10 400 mg, AG10 800 mg, or placebo twice daily for 28 days. Safety and tolerability were assessed by clinical and laboratory criteria. AG10 plasma levels were measured. TTR stability was assessed by changes in serum TTR, and 2 established ex vivo assays (fluorescent probe exclusion and Western blot). RESULTS: AG10 treatment was well-tolerated, achieved target plasma concentrations and demonstrated near-complete stabilization of TTR. TTR stabilization was more complete and less variable at the higher dose with stabilization by fluorescent probe exclusion of 92 ± 10% (mean ± SD) at trough and 96 ± 9% at peak (both p < 10-12 vs. placebo). Average serum TTR increased by 36 ± 21% and 51 ± 38% at 400 and 800 mg, respectively (both p < 0.0001 vs. placebo). Baseline serum TTR in treated subjects was below normal in 80% of mutant and 33% of wild-type subjects. AG10 treatment restored serum TTR to the normal range in all subjects. CONCLUSIONS: AG10 has the potential to be a safe and effective treatment for patients with ATTR-CM. A phase 3 trial is ongoing. (Study of AG10 in Amyloid Cardiomyopathy; NCT03458130).

Genotype and Lifetime Burden of Disease in Hypertrophic Cardiomyopathy: Insights from the Sarcomeric Human Cardiomyopathy Registry (SHaRe).

Background: A better understanding of the factors that contribute to heterogeneous outcomes and lifetime disease burden in hypertrophic cardiomyopathy (HCM) is critically needed to improve patient management and outcomes. The Sarcomeric Human Cardiomyopathy Registry (SHaRe) was established to provide the scale of data required to address these issues, aggregating longitudinal datasets curated by eight international HCM specialty centers. Methods: Data on 4591 HCM patients (2763 genotyped), followed for a mean of 5.4±6.9 years (24,791 patient-years; median [interquartile range] 2.9 [0.3-7.9] years) were analyzed regarding cardiac arrest, cardiac transplantation, appropriate implantable cardioverter-defibrillator (ICD) therapy, all-cause death, atrial fibrillation, stroke, New York Heart Association Functional Class III/IV symptoms (all comprising the overall composite endpoint), and left ventricular ejection fraction (LVEF)<35%. Outcomes were analyzed individually and as composite endpoints. Results: Median age of diagnosis was 45.8 [30.9-58.1] years and 37% of patients were female. Age of diagnosis and sarcomere mutation status were predictive of outcomes. Patients <40 years old at diagnosis had a 77% [95% confidence interval: 72%, 80%] cumulative incidence of the overall composite outcome by age 60, compared to 32% [29%, 36%] by age 70 for patients diagnosed >60 years. Young HCM patients (20-29 years) had 4-fold higher mortality than the general United States population at a similar age. Patients with pathogenic/likely pathogenic sarcomere mutations had two-fold greater risk for adverse outcomes compared to patients without mutations; sarcomere variants of uncertain significance were associated with intermediate risk. Heart failure and atrial fibrillation were the most prevalent adverse events, although typically not emerging for several years after diagnosis. Ventricular arrhythmias occurred in 32% [23%, 40%] of patients <40 years at diagnosis, but in 1% [1%, 2%] >60 years. Conclusions: The cumulative burden of HCM is substantial and dominated by heart failure and atrial fibrillation occurring many years following diagnosis. Young age of diagnosis and the presence of a sarcomere mutation are powerful predictors of adverse outcomes. These findings highlight the need for close surveillance throughout life, and the need to develop disease-modifying therapies.

Navigating the Future of Cardiovascular Drug Development-Leveraging Novel Approaches to Drive Innovation and Drug Discovery: Summary of Findings from the Novel Cardiovascular Therapeutics Conference.

PURPOSE: The need for novel approaches to cardiovascular drug development served as the impetus to convene an open meeting of experts from the pharmaceutical industry and academia to assess the challenges and develop solutions for drug discovery in cardiovascular disease. METHODS: The Novel Cardiovascular Therapeutics Summit first reviewed recent examples of ongoing or recently completed programs translating basic science observations to targeted drug development, highlighting successes (protein convertase sutilisin/kexin type 9 [PCSK9] and neprilysin inhibition) and targets still under evaluation (cholesteryl ester transfer protein [CETP] inhibition), with the hope of gleaning key lessons to successful drug development in the current era. Participants then reviewed the use of innovative approaches being explored to facilitate rapid and more cost-efficient evaluations of drug candidates in a short timeframe. RESULTS: We summarize observations gleaned from this summit and offer insight into future cardiovascular drug development. CONCLUSIONS: The rapid development in genetic and high-throughput drug evaluation technologies, coupled with new approaches to rapidly evaluate potential cardiovascular therapies with in vitro techniques, offer opportunities to identify new drug targets for cardiovascular disease, study new therapies with better efficiency and higher throughput in the preclinical setting, and more rapidly bring the most promising therapies to human testing. However, there must be a critical interface between industry and academia to guide the future of cardiovascular drug development. The shared interest among academic institutions and pharmaceutical companies in developing promising therapies to address unmet clinical needs for patients with cardiovascular disease underlies and guides innovation and discovery platforms that are significantly altering the landscape of cardiovascular drug development.

SHaRe: advancing the goal of effective treatment for cardiomyopathy.

The new Sarcomeric Human Cardiomyopathy Registry (SHaRe) is discussed by Dr Jonathon C. Fox.

Restoration of cytoskeleton homeostasis after gigaxonin gene transfer for giant axonal neuropathy.

Giant axonal neuropathy (GAN) is caused by loss of function of the gigaxonin protein. On a cellular level GAN is characterized by intermediate filament (IF) aggregation, leading to a progressive and fatal peripheral neuropathy in humans. This study sought to determine if re-introduction of the GAN gene into GAN-deficient cells and mice would restore proper cytoskeleton IF homeostasis. Treatment of primary skin fibroblast cultures from three different GAN patients with an adeno-associated virus type 2 (AAV2) vector containing a normal human GAN transgene significantly reduced the number of cells displaying vimentin IF aggregates. A proteomic analysis of these treated cells was also performed, wherein the abundance of 32 of 780 identified proteins significantly changed in response to gigaxonin gene transfer. While 29 of these responding proteins have not been directly described in association with gigaxonin, three were previously identified as being disregulated in GAN and were now shifted toward normal levels. To assess the potential application of this approach in vivo and eventually in humans, GAN mice received an intracisternal injection of an AAV9/GAN vector to globally deliver the GAN gene to the brainstem and spinal cord. The treated mice showed a nearly complete clearance of peripherin IF accumulations at 3 weeks post-injection. These studies demonstrate that gigaxonin gene transfer can reverse the cellular IF aggregate pathology associated with GAN.

AMP-activated protein kinase inhibits vascular smooth muscle cell proliferation and migration and vascular remodeling following injury.

Vascular smooth muscle cell (VSMC) activation promotes a synthetic phenotype that underlies many vessel growth disorders. In this regard it has been suggested that the metabolic sensor adenosine 5'-monophosphate-activated protein kinase (AMPK) has significant antigrowth and antimetastatic properties and may serve as a viable therapeutic target. In the current study we hypothesized that AMPK reduces neointima formation following balloon injury and that this occurs through reduction in VSMC proliferation and migration. Data reveal that local or systemic dosing with the AMPK agonist 5-aminoimidazole-4-carboxamide-1-ß-d-ribofuranoside (AICAR) significantly increased AMPK activity in vivo and inhibited neointima formation in rat carotid arteries 2 wk after injury. In primary VSMCs, AICAR inhibited migration and induced cytostatic growth arrest through increased protein phosphatase 2A-mediated inhibition of mitosis-promoting cyclin B. AICAR also significantly enhanced AMPK-specific T278 phosphorylation of the actin anticapping vasodilator-activated serum phosphoprotein, increased G- to F-actin ratios and stress fiber formation, and abrogated PDGF-stimulated S397 autophosphorylation of focal adhesion kinase, promigratory cytoplasmic accumulation of paxillin, and extracellular matrix proteolysis by matrix metalloproteinase-9. Together, these results provide compelling evidence that AMPK serves to inhibit vascular smooth muscle migration and proliferation through regulation of cytoskeletal/focal adhesion/ECM stability, increasing our knowledge of this important metabolic regulator and providing support for its continued investigation in the treatment of vascular growth disorders.

The soluble guanylate cyclase stimulator BAY 41-2272 inhibits vascular smooth muscle growth through the cAMP-dependent protein kinase and cGMP-dependent protein kinase pathways.

Vascular smooth muscle (VSM) proliferation and migration are key components in vessel remodeling. Cyclic nucleotide signaling is protective and has long-served as a therapeutic target against undesired VSM growth. The present work analyzed the effects of the soluble guanylate cyclase (sGC) stimulator 3-(4-amino-5-cyclopropylpyrimidine-2-yl)-1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine [BAY 41-2272 (BAY)] on VSM growth, and we hypothesize that BAY has the capacity to reduce proliferation and migration via cyclic nucleotide-driven kinase signaling. Perivascular BAY postballoon injury reduced neointimal growth by ∼ 40% compared with vehicle controls after 2 weeks. In VSM cells, BAY (10 µM) reduced proliferation by ∼ 40% after 72 h and migration by ∼ 40% after 6 h and ∼ 60% after 18 h without deleterious effects on cell viability. cGMP content peaked (248 ×) 20 min after BAY treatment and remained elevated (140 ×) through 60 min; however, BAY did not affect cAMP levels compared with controls. Conventional and In-Cell Western analyses showed increases in vasodilator-stimulated phosphoprotein (VASP) phosphorylation (pVASP) at serines 239 (3 ×) and 157 (2 ×), respective markers of cGMP- and cAMP-directed protein kinases (PKG and PKA, respectively). The PKG inhibitor YGRKKRRQRRRPPLRKKKKKH peptide (DT-2) completely reversed BAY-mediated increases in pVASPSer(239) and BAY-mediated inhibition of migration. In comparison, the PKA inhibitor peptide PKI further potentiated BAY-stimulated pVASPSer(157) and pVASPSer(239) and partially reversed the antiproliferative effects of BAY. This is the first report demonstrating the effectiveness of BAY in reducing neointimal growth with direct evidence for PKG-specific antimigratory and PKA-specific antiproliferative mechanisms. Conclusively, the sGC stimulator BAY reduces VSM growth through cGMP-dependent PKG and PKA processes, providing support for continued evaluation of its clinical utility.

Effect of rosuvastatin 5-20mg on triglycerides and other lipid parameters in Japanese patients with hypertriglyceridemia.

To evaluate the potential dose effect of rosuvastatin on triglyceride (TG) levels in Japanese hypertriglyceridemic patients, we randomized 154 patients with TG levels of >or=200 and <800 mg/dL to 8 weeks of treatment with rosuvastatin 5, 10 or 20mg once daily; bezafibrate 200mg twice daily; or placebo. Compared with placebo, TG was reduced by 30.1% with rosuvastatin 5mg, 30.1% with 10mg and 32.3% with 20mg (all p

The comparative safety of rosuvastatin: a retrospective matched cohort study in over 48,000 initiators of statin therapy.

PURPOSE: The purpose of this study was to compare incidence rates of hospitalization associated with rhabdomyolysis, myopathy, renal, or hepatic dysfunction, and of in-hospital death, between initiators of rosuvastatin and other statins. METHODS: This was a matched cohort study of statin initiators from the administrative database of a large health insurer in the US, during the first 6 months of rosuvastatin availability with up to 18 months of follow-up. All outcome events were verified by medical record review. Incidence rates, risk ratios, and associated 95% confidence intervals were estimated. RESULTS: From an initial pool of 12,217, 11,249 eligible rosuvastatin initiators were matched to 37,282 initiators of other statins. The incidence rate (IR) per 1000 person-years for rhabdomyolysis was 0.10 [0.00, 0.55] for rosuvastatin initiators (n = 1) and 0.06 [0.01, 0.22] for other statin initiators (n = 2), for a hazard ratio (HR) of 1.98 [0.18, 21.90]. The IR for myopathy was 0.20 [0.02, 0.71] for rosuvastatin initiators (n = 2) and 0.00 [0.00, 0.09] for other statin initiators (n = 0). The IR for renal dysfunction was 1.18 [0.61, 2.06] for rosuvastatin initiators (n = 12) and 1.26 [0.91, 1.71] for other statin initiators (n = 42), for a HR of 0.90 [0.47, 1.73]. The IR for hepatic dysfunction was 0.20 (0.02, 0.71) for rosuvastatin initiators (n = 2) and 0.24 (0.10, 0.47) for other statin initiators (n = 8), for a HR of 0.87 (0.18, 4.14). CONCLUSIONS: This study found no difference between rosuvastatin and the other statins in the incidence of hospitalizations associated with renal or hepatic events, or death. The absolute incidence rates of rhabdomyolysis and myopathy were reassuringly low among all statin initiators but remain too small for firm conclusions to be drawn on any difference between the statins.

The JNC 7 approach compared to conventional treatment in diabetic patients with hypertension: a double-blind trial of initial monotherapy vs. combination therapy.

The JNC 7 states that persons with blood pressure (BP) more than 20/10 mm Hg above goal should be started on combination drug therapy. This criterion includes patients with BP >160/100 mm Hg and diabetics with hypertension. The goal BP for persons with diabetes mellitus is <130/80 mm Hg. A randomized, double-blind trial force titrated initial combination therapy utilizing an angiotensin receptor blocker (ARB) combination (losartan/hydrochlorothiazide [LOS/HCTZ]) compared with an angiotensin-converting enzyme (ACE) inhibitor (ramipril), for 8 weeks, and tested the hypothesis that combination therapy is more likely to achieve goal BP vs. monotherapy. At 4 weeks, 30.5% of LOS/HCTZ and 14.4% of ramipril recipients achieved goal diastolic BP (p<0.001). More participants achieved goal systolic BP in the ARB/HCTZ group at 4 weeks (29.8% vs. 14.4%; p<0.001). At 4 weeks, mean diastolic BP had decreased 10.2+/-7.4 mm Hg in the LOS/HCTZ group compared with 6.4+/-6.8 mm Hg in the ramipril group (p<0.001), and systolic BP had fallen 15.4+/-13.1 mm Hg in the ARB/HCTZ compared with 9.2+/-10.2 mm Hg in the ACE-inhibitor group (p<0.001). Significant differences favoring the combination were also noted at 8 weeks. Drug-related adverse experiences were 10.3% for the combination compared with 12.7% for the monotherapy group. Initial combination therapy with an ARB/HCTZ was more effective than ACE-inhibitor monotherapy in achieving BP goals in participants with diabetes with no significant differences in the incidence of adverse experiences. These observations confirm other studies of combination therapies, such as b blocker/diuretic, ACE inhibitor/diuretic, or ACE inhibitor/calcium channel blocker. The use of two medications will achieve goal BP in more patients than monotherapy. This observation is important in treatment of high-risk patients with diabetes.

Investigating cardiovascular risk reduction--the Rosuvastatin GALAXY Programme.

The GALAXY Programme is a comprehensive global research initiative that will address several important unanswered questions in statin research and investigate the impact of rosuvastatin on cardiovascular risk reduction and patient outcomes. Studies already completed demonstrate that rosuvastatin provides greater reductions in low-density lipoprotein cholesterol (LDL-C) than other statins, enabling more patients to achieve LDL-C treatment goals. Additionally, rosuvastatin provides beneficial effects on other components of the atherogenic lipid profile. Ongoing studies will evaluate whether these effects translate into beneficial effects on atherosclerosis and significant reductions in cardiovascular events. Important information will also be provided on the role of statins in less well studied groups, including patients with heart failure, end stage renal disease, and individuals without elevated LDL-C but at heightened vascular risk as a result of increased systemic inflammation. Ultimately, the GALAXY Programme will provide clinical data that will enable physicians to make more effective statin treatment decisions, which will lead to improved patient care and cardiovascular outcomes.

Autocrine signaling through Ras regulates cell survival activity in human glioma cells: potential cross-talk between Ras and the phosphatidylinositol 3-kinase-Akt pathway.

Autocrine fibroblast growth factor (FGF) signaling mediates an uncontrollable growth of human gliomas. We investigated the intracellular signaling of FGF on cell survival activity. U251MG human glioma cells were infected with adenovirus vectors expressing dominant negative type I FGF receptor (DNFR), constitutive active Ras (RasL61), or dominant negative Ras (RasN17). DNFR reduced glioma cell accumulation with apoptosis and this reduction was alleviated with exogenous epidermal growth factor (EGF), which can activate Ras independent of FGFR but not with bFGF. RasL61 prevented but RasN17-enhanced DNFR-induced apoptosis. Reportedly, cell survival signaling through Akt was constitutively active in U251MG cells and this effect may be dependent on autocrine signaling and dysfunction of PTEN, a tumor suppressor gene limiting phosphatidylinositol 3-kinase (PI3K) activity. DNFR dose-dependently inhibited Akt activity and this inhibition was recovered by RasL61, whereas RasN17 inhibited Akt activity. Wortmannin (a PI3K inhibitor) inhibited Akt activity and mildly promoted apoptosis. RasL61 prevented the down-regulation of Akt activity and apoptosis induced by wortmannin, but RasN17 plus wortmannin strongly inhibited Akt activity and promoted marked apoptosis. Our data suggested that the cell survival activity of human gliomas is largely dependent on cross-talk between Ras and the PI3K-Akt pathway, and this cross-talk could be a potential target for molecular-based therapeutics.

Inhibition of autocrine fibroblast growth factor signaling by the adenovirus-mediated expression of an antisense transgene or a dominant negative receptor in human glioma cells in vitro.

Autocrine fibroblast growth factor (FGF) signaling was genetically manipulated in human gliomas by an adenovirus-mediated strategy. Antisense inhibition of endogenous basic FGF (bFGF) expression showed inhibition of the proliferation of human glioma cells (U251MG, NMC-G1) without promoting apoptosis. The reduction in proliferation in response to antisense inhibition was reversed with an additional supplement of exogenous bFGF. On the other hand, the overexpression of a kinase defective mutant of the type I FGF receptor (dominant negative FGF receptor) resulted in not only growth inhibition but also marked apoptosis in U251MG cells. In the cells expressing a dominant negative FGF receptor, the reduction in cell number was not reversed by the exogenous bFGF supplement. Our data further implicated the significance of an autocrine FGF signaling loop in human gliomas. Cell survival activity may largely depend on the receptor-mediated pathway, which should be considered in the development of the molecular based therapeutics.