ABSTRACT
Purpose: Methotrexate (MTX) is a first-line drug for rheumatoid arthritis (RA)therapy. However, MTX monotherapy often results in irreversible joint damage due to its slow onset of action and long duration. microRNA-124 (miR-124) has shown direct bone protection activity against RA. A co-delivery system for MTX and microRNA combination may provide therapeutic synergy. Methods: Methotrexate-conjugated polymer hybrid micelles (M-PHMs) were prepared by self-assembly of two functional amphiphilic polymers (MTX-PEI-LA and mPEG-LA) at an optimized weight ratio. Incorporation of microRNA was achieved through electrostatic interactions between microRNA and cationic polymer MTX-PEI-LA. Cellular uptake, endosome escape, biodistribution, and therapeutic efficacy of M-PHMs/miR-124 complexes were investigated and evaluated in RAW264.7 cells and a rat adjuvant-induced arthritis (AIA) model. Results: M-PHMs/miR-124 complexes exhibited folate receptor-mediated uptake in activated RAW264.7 cells. miR-124 was able to escape from the endosome and down-regulate nuclear factor of activated T cells cytoplasmic1 (NFATc1). M-PHMs/miR-124 complexes accumulated in inflamed joints of AIA rats and showed superior therapeutic efficacy through both anti-inflammatory effect and direct bone protective effect. Combination of miR-124 and MTX in these micelles induced disease remission. Conclusions: M-PHMs/miR-124 was highly effective against RA through therapeutic synergy. Additional studies are warranted to further investigate its therapeutic potential and delineate its mechanisms of action.
Subject(s)
Arthritis, Rheumatoid/drug therapy , Methotrexate/therapeutic use , Micelles , MicroRNAs/metabolism , Polymers/chemistry , Animals , Arthritis, Rheumatoid/blood , Cell Death/drug effects , Cytokines/blood , Disease Models, Animal , Endocytosis/drug effects , Endosomes/metabolism , Folate Receptor 1/metabolism , Hemolysis/drug effects , Inflammation Mediators/blood , Joints/pathology , Linoleic Acid/chemical synthesis , Lipopolysaccharides , Methotrexate/pharmacology , Mice , MicroRNAs/genetics , NFATC Transcription Factors/metabolism , Polyethylene Glycols/chemical synthesis , Polyethyleneimine/chemical synthesis , Proton Magnetic Resonance Spectroscopy , RAW 264.7 Cells , Rats , Tissue Distribution/drug effectsABSTRACT
BACKGROUND/AIM: Effective and targeted delivery of siRNA to tumor cells is a prerequisite to achieving their therapeutic effects. Survivin is up-regulated in tumor cells and is associated with resistance to therapy. Therefore, siRNA-mediated silencing of survivin is a potential therapeutic strategy for cancer. The aim of the study was to examine whether polymeric hybrid micelles can be used to effectively deliver siRNAs into cells. MATERIALS AND METHODS: First, linoleic acid (LA) was conjugated to polyethylenimine (PEI) and methoxy-polyethyleneglycol (mPEG) and two amphiphilic polymers (PEI-LA and mPEG-LA) were obtained. Polymeric hybrid micelle (PHM) was then prepared and characterized by self-assembly of PEI-LA and mPEG-LA at different percentages of the two amphiphilic polymers. A PHM/siRNA complex with optimized composition and good biocompatibility was then prepared and its cellular uptake, biodistribution, and antitumor effects were investigated. RESULTS: Survivin siRNA was efficiently delivered to the cells. It reduced survivin protein expression and greatly suppressed tumor growth. Moreover, siRNA loaded in PHM gathered in a solid tumor in mice and achieved an improved anticancer effect compared to naked siRNA. CONCLUSION: PHM is a promising and safe vehicle for siRNA delivery and may find utility in cancer therapy.
Subject(s)
Micelles , Neoplasms/therapy , RNA, Small Interfering/administration & dosage , A549 Cells , Animals , Cell Survival/drug effects , Female , Humans , Linoleic Acid/administration & dosage , Linoleic Acid/chemistry , Mice, Inbred BALB C , Mice, Nude , Neoplasms/genetics , Neoplasms/metabolism , Neoplasms/pathology , Polyethylene Glycols/administration & dosage , Polyethylene Glycols/chemistry , Polyethyleneimine/administration & dosage , Polyethyleneimine/chemistry , RNA, Small Interfering/pharmacokinetics , Survivin/genetics , Survivin/metabolism , Tumor BurdenABSTRACT
A combination of chemotherapeutic drugs and siRNA is emerging as a new modality for cancer therapy. A safe and effective carrier platform is needed for combination drug delivery. Here, a functionalized mixed micelle-based delivery system was developed for targeted co-delivery of methotrexate (MTX) and survivin siRNA. Linolenic acid (LA) was separately conjugated to branched polyethlenimine (b-PEI) and methoxy-polyethyleneglycol (mPEG). MTX was then conjugated to LA-modified b-PEI (MTX-bPEI-LA) to form a functionalized polymer-drug conjugate. Functionalized mixed micelles (M-MTX) were obtained by the self-assembly of MTX-bPEI-LA and LA-modified mPEG (mPEG-LA). M-MTX had a narrow particle size distribution and could successfully condense siRNA at an N/P ratio of 16/1. M-MTX/siRNA was selectively taken up by HeLa cells overexpressing the folate receptor (FR) and facilitated the release of the siRNA into the cytoplasm. In vitro, M-MTX/siRNA produced a synergy between MTX and survivin siRNA and markedly suppressed survivin protein expression. In tumor-bearing mice, M-MTX/Cy5-siRNA showed an elevated tumor uptake. In addition, M-MTX/siRNA inhibited tumor growth. Immunohistochemistry and a western blot analysis showed a significant target gene downregulation. In conclusion, M-MTX/siRNA was highly effective as a delivery system and may serve as a model for the targeted co-delivery of therapeutic agents.
