RESUMO
Provoked by sterile/nonsterile insults, prolonged monocyte mobilization and uncontrolled monocyte/macrophage activation can pose imminent or impending harm to the affected organs. Curiously, folate receptor beta (FRß), with subnanomolar affinity for the vitamin folic acid (FA), is upregulated during immune activation in hematopoietic cells of the myeloid lineage. This phenomenon has inspired a strong interest in exploring FRß-directed diagnostics/therapeutics. Previously, we have reported that FA-targeted aminopterin (AMT) therapy can modulate macrophage function and effectively treat animal models of inflammation. Our current investigation of a lead compound (EC2319) leads to discovery of a highly FR-specific mechanism of action independent of the root causes against inflammatory monocytes. We further show that EC2319 suppresses interleukin-6/interleukin-1ß release by FRß+ monocytes in a triple co-culture leukemic model of cytokine release syndrome with anti-CD19 chimeric antigen receptor T cells. Because of its chemical stability and metabolically activated linker, EC2319 demonstrates favorable pharmacokinetic characteristics and cross-species translatability to support future pre-clinical and clinical development.
Assuntos
Aminopterina/farmacologia , Síndrome da Liberação de Citocina/prevenção & controle , Receptor 2 de Folato/genética , Antagonistas do Ácido Fólico/farmacologia , Ácido Fólico/metabolismo , Macrófagos/efeitos dos fármacos , Animais , Antígenos CD19/genética , Antígenos CD19/imunologia , Células CHO , Cricetulus , Síndrome da Liberação de Citocina/genética , Síndrome da Liberação de Citocina/imunologia , Síndrome da Liberação de Citocina/patologia , Feminino , Receptor 1 de Folato/antagonistas & inibidores , Receptor 1 de Folato/genética , Receptor 1 de Folato/imunologia , Receptor 2 de Folato/antagonistas & inibidores , Receptor 2 de Folato/imunologia , Humanos , Interleucina-1beta/genética , Interleucina-1beta/imunologia , Interleucina-6/genética , Interleucina-6/imunologia , Ativação de Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/patologia , Camundongos , Modelos Biológicos , Monócitos/efeitos dos fármacos , Monócitos/imunologia , Monócitos/patologia , Células RAW 264.7 , Ratos , Ratos Endogâmicos Lew , Receptores de Antígenos Quiméricos/genética , Receptores de Antígenos Quiméricos/imunologia , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Linfócitos T/patologiaRESUMO
Folate receptor (FR)-targeted small molecule drug conjugates (SMDCs) have shown promising results in early stage clinical trials with microtubule destabilizing agents, such as vintafolide and EC1456. In our effort to develop FR-targeted SMDCs with varying mechanisms of action, we synthesized EC2629, a folate conjugate of a DNA crosslinking agent based on a novel DNA-alkylating moiety. This agent was found to be extremely potent with an in vitro IC50 ~ 100× lower than folate SMDCs constructed with various microtubule inhibitors. EC2629 treatment of nude mice bearing FR-positive KB human xenografts led to cures in 100% of the test animals with very low dose levels (300 nmol/kg) following a convenient once a week schedule. The observed activity was not accompanied by any noticeable weight loss (up to 20 weeks post end of dosing). Complete responses were also observed against FR-positive paclitaxel (KB-PR) and cisplatin (KB-CR) resistant models. When evaluated against FR-positive patient derived xenograft (PDX) models of ovarian (ST070), endometrial (ST040) and triple negative breast cancers (ST502, ST738), EC2629 showed significantly greater anti-tumor activity compared to their corresponding standard of care treatments. Taken together, these studies thus demonstrated that EC2629, with its distinct DNA reacting mechanism, may be useful in treating FR-positive tumors, including those that are classified as drug resistant.
Assuntos
Antineoplásicos/farmacologia , Reagentes de Ligações Cruzadas/farmacologia , DNA/química , Neoplasias do Endométrio/tratamento farmacológico , Receptores de Folato com Âncoras de GPI/química , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Alquilantes/química , Animais , Bovinos , Cisplatino/administração & dosagem , Cães , Sistemas de Liberação de Medicamentos , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos , Feminino , Ácido Fólico/análogos & derivados , Ácido Fólico/farmacologia , Humanos , Concentração Inibidora 50 , Células KB , Ligantes , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Nus , Paclitaxel/administração & dosagem , Ratos , Alcaloides de Vinca/farmacologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
EC1456 is a folate-tubulysin conjugate constructed with an all-D enantiomeric spacer/linker configuration. When tested against folate receptor (FR)-positive cells, EC1456 demonstrated dose-responsive activity with an approximate 1000-fold level of specificity. Treatment of nude mice bearing FR-positive human xenografts (as large as 800 mm3) with non-toxic doses of EC1456 led to cures in 100% of the mice. Combinations of low dose EC1456 with standard of care agents such as platins, taxanes, topotecan and bevacizumab, safely and significantly augmented the growth inhibitory effects of these commonly used agents. When tested against FR-positive human tumor xenograft models having confirmed resistance to a folate-vinca alkaloid (vintafolide), cisplatin or paclitaxel, EC1456 was found to generate partial to curative responses. Taken together, these studies demonstrate that EC1456 has significant anti-proliferative activity against FR-positive tumors, including models which were anticancer drug resistant, thereby justifying a Phase 1 trial of this agent for the treatment of advanced human cancers.
