RESUMO
Phosphoinositide 3-kinase (PI3K) pathway mediates key signaling events downstream to B-cell receptor (BCR) for survival of mature B-cells, and overexpression or overactivation of PI3Kδ is crucial for B-cell malignancies such as diffuse large B-cell lymphoma (DLBCL). Small molecule PI3Kδγ inhibitors, with a known potential to reduce activated B-cell (ABC)-DLBCL transformation, form an important class of therapeutics approved for follicular lymphoma (FL), chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma (SLL). In this study, we describe discovery of a potent, selective and efficacious dual PI3Kδγ inhibitor, LL-00084282, having a differentiated efficacy profile in human ABC- and germinal center B-cell (GCB)-DLBCL cell lines. LL-00084282 displayed high potency and superior PI3Kδγ engagement with excellent selectivity over other PI3K isoforms at both IC50/90 concentrations in biochemical and cell-based assays. In contrast to selective PI3Kδ inhibitors, LL-00084282 showed superior and potent anticancer activity in both ABC- and GCB-DLBCL cell lines. LL-00084282 demonstrated in-vivo efficacy in OCI-Ly10 and SU-DHL-6 xenografts with good tolerability. Furthermore, LL-00084282 inhibited pro-inflammatory cytokine secretion and reduced basophil activation in human PBMCs, showing potential implications in immunoinflammatory conditions. Good pharmacokinetic properties in higher species and desirable efficacy profile highlights potential of this novel PI3Kδγ inhibitor for further clinical evaluation in DLBCL patients.
Assuntos
Leucemia Linfocítica Crônica de Células B , Linfoma Difuso de Grandes Células B , Inibidores de Fosfoinositídeo-3 Quinase , Humanos , Linfócitos B , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Fosfatidilinositol 3-Quinases , Inibidores de Fosfoinositídeo-3 Quinase/farmacologia , Linhagem Celular TumoralRESUMO
α7 nicotinic acetylcholine receptor (α7 nAChR) is an extensively validated target for several neurological and psychiatric conditions namely, dementia and schizophrenia, owing to its vital roles in cognition and sensorimotor gating. Positive allosteric modulation (PAM) of α7 nAChR represents an innovative approach to amplify endogenous cholinergic signaling in a temporally restricted manner in learning and memory centers of brain. α7 nAChR PAMs are anticipated to side-step burgeoning issues observed with several clinical-stage orthosteric α7 nAChR agonists, related to selectivity, tolerance/tachyphylaxis, thus providing a novel dimension in therapeutic strategy and pharmacology of α7 nAChR ion-channel. Here we describe a novel α7 nAChR PAM, LL-00066471, which potently amplified agonist-induced Ca2+ fluxes in neuronal IMR-32 neuroblastoma cells in a α-bungarotoxin (α-BTX) sensitive manner. LL-00066471 showed excellent oral bioavailability across species (mouse, rat and dog), low clearance and good brain penetration (B/P ratio > 1). In vivo, LL-00066471 robustly attenuated cognitive deficits in both procognitive and antiamnesic paradigms of short-term episodic and recognition memory in novel object recognition task (NORT) and social recognition task (SRT), respectively. Additionally, LL-00066471 mitigated apomorphine-induced sensorimotor gating deficits in acoustic startle reflex (ASR) and enhanced antipsychotic efficacy of olanzapine in conditioned avoidance response (CAR) task. Further, LL-00066471 corrected redox-imbalances and reduced cortico-striatal infarcts in stroke model. These finding together suggest that LL-00066471 has potential to symptomatically alleviate cognitive deficits associated with dementias, attenuate sensorimotor gating deficits in schizophrenia and correct redox-imbalances in cerebrovascular disorders. Therefore, LL-00066471 presents potential for management of cognitive impairments associated with neurological and psychiatric conditions.
Assuntos
Comportamento Animal/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Colinérgicos/farmacologia , Cognição/efeitos dos fármacos , Disfunção Cognitiva/prevenção & controle , Transtornos Neurológicos da Marcha/prevenção & controle , Filtro Sensorial/efeitos dos fármacos , Receptor Nicotínico de Acetilcolina alfa7/efeitos dos fármacos , Animais , Encéfalo/metabolismo , Encéfalo/fisiopatologia , Linhagem Celular Tumoral , Colinérgicos/farmacocinética , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/fisiopatologia , Disfunção Cognitiva/psicologia , Modelos Animais de Doenças , Cães , Comportamento Exploratório/efeitos dos fármacos , Transtornos Neurológicos da Marcha/metabolismo , Transtornos Neurológicos da Marcha/fisiopatologia , Transtornos Neurológicos da Marcha/psicologia , AVC Isquêmico/tratamento farmacológico , AVC Isquêmico/metabolismo , AVC Isquêmico/fisiopatologia , Masculino , Camundongos Endogâmicos BALB C , Teste de Campo Aberto/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ratos Sprague-Dawley , Ratos Wistar , Reflexo de Sobressalto/efeitos dos fármacos , Transdução de Sinais , Comportamento Social , Receptor Nicotínico de Acetilcolina alfa7/metabolismoRESUMO
Beta-amyloid peptide (Aß) induced neurotoxicity is considered as a hallmark of the pathogenesis of Alzheimer's disease (AD). The present study demonstrated the neuroprotective role of 5-HT6 receptors against Aß-induced neurotoxicity in PC-12 cells. The 5-HT6 receptor agonist EMD-386088 and antagonist SB-399885 were used as pharmacological tools. The NMDA receptor antagonist, memantine, was used as reference standard. The Aß25-35 (50 µM) induced apoptosis, increased reactive oxygen species (ROS) generation and impaired neurite outgrowth in PC-12 cells. Pre-treatment with 10 µM EMD-386088 and SB-399885 had significantly protected neuronal cell death by maintaining higher cell viability through attenuation of intracellular ROS. Further, both compounds significantly prevented Aß25-35-induced impairment in neurite outgrowth in PC-12 cells. Similarly, memantine prevented Aß25-35-induced neurotoxicity in PC-12 cells. These findings suggest that 5-HT6 receptor ligands have protected neurons from Aß25-35 induced toxicity by reducing ROS and through prevention of impairment in neurite outgrowth. Therefore, 5-HT6 receptor could be an important disease-modifying therapeutic target for AD.