An advanced multifunctional, hollow metal-organic framework (MOF) drug delivery system with a high drug loading level and targeted delivery was designed and fabricated for the first time and applied to inhibit tumour cell growth. This hollow MOF targeting drug delivery system was prepared via a simple post-synthetic surface modification procedure, starting from hollow ZIF-8 successfully obtained for the first time via a mild phase transformation under solvothermal conditions. As a result, the hollow ZIF-8 exhibits a higher loading capacity for the model anticancer drug 5-fluorouracil (5-FU). Subsequently, 5-FU-loaded ZIF-8 was encapsulated into polymer layers (FA-CHI-5-FAM) with three components: a chitosan (CHI) backbone, the imaging agent 5-carboxyfluorescein (5-FAM), and the targeting reagent folic acid (FA). Thus, an advanced drug delivery system, ZIF-8/5-FU@FA-CHI-5-FAM, was fabricated. A cell imaging assay demonstrated that ZIF-8/5-FU@FA-CHI-5-FAM could target and be taken up by MGC-803 cells. Furthermore, the as-prepared ZIF-8/5-FU@FA-CHI-5-FAM exhibited stronger cell growth inhibitory effects on MGC-803 cells because of the release of 5-FU, as confirmed by a cell viability assay. In addition, a drug release experiment in vitro indicated that ZIF-8/5-FU@FA-CHI-5-FAM exhibited high loading capacity (51%) and a sustained drug release behaviour. Therefore, ZIF-8/5-FU@FA-CHI-5-FAM could provide targeted drug transportation, imaging tracking and localized sustained release.

RNA interference is an evolutionarily conserved gene-silencing phenomenon that shows great promise for developing new therapies. However, the development of small interfering RNA (siRNA)-based therapies needs to overcome two barriers and be able to (i) identify chemically stable and effective siRNA sequences and (ii) efficiently silence target genes with siRNA doses that will be clinically feasible in humans. Here, we report the design and creation of interfering nanoparticles (iNOPs) as new systemic gene-silencing agents. iNOPs have two subunits: (i) a well-defined functionalized lipid nanoparticle as a delivery agent and (ii) a chemically modified siRNA for sustained silencing in vivo. When we injected iNOPs containing only 1-5 mg kg(-1) siRNA into mice, an endogenous gene for apolipoprotein B (apoB) was silenced in liver, plasma levels of apoB decreased, and total plasma cholesterol was lowered. iNOP treatment was nontoxic and did not induce an immune response. Our results show that these iNOPs can silence disease-related endogenous genes in clinically acceptable and therapeutically affordable doses.

MicroRNAs (miRNAs) are small endogenous non-coding RNAs that regulate post-transcriptional gene expression and are important in many biological processes. Disease-associated miRNAs have been shown to become potential targets for therapeutic intervention. Functions of miRNAs can be inhibited by using antisense oligonucleotides, called anti-miRs, complimentary to the miRNA sequences. Here, we show that systemic delivery of a chemically stabilized anti-miR-122 complexed with interfering nanoparticles (iNOPs) effectively silences the liver-expressed miR-122 in mice. Intravenous administration of 2 mg kg−1 chemically modified anti-miR-122 complexed with iNOP-7 resulted in 83.2 ± 3.2% specific silencing of miR-122, which was accompanied by regulating gene expression in liver and lowering of plasma cholesterol. The specific silencing of miR-122 was long lasting and did not induce an immune response. Our results demonstrate that iNOPs can successfully deliver anti-miR to specifically target and silence miRNA in clinically acceptable and therapeutically affordable doses.

Inherited neurodegenerative diseases, such as Huntington disease and subset of Alzheimer disease, Parkinson disease, and amyotrophic lateral sclerosis, are caused by the mutant genes that have gained undefined properties that harm cells in the nervous system, causing neurodegeneration and clinical phenotypes. Lowering the mutant gene expression is predicted to slow the disease progression and produce clinical benefit. Administration of small interfering RNA (siRNA) can silence specific genes. However, long term delivery of siRNA to silence the mutant genes, a requirement for treatment of these chronic central nervous system (CNS) diseases, remains a critical unsolved issue. Here we designed and tested a chemically stabilized siRNA against human Cu,Zn-superoxide dismutase (SOD1) in a mouse model for amyotrophic lateral sclerosis. We show that the modified siRNA has enhanced stability and retains siRNA activity. Administration of this siRNA at the disease onset by long term infusion into the CNS resulted in widespread distribution of this siRNA, knocked down the mutant SOD1 expression, slowed the disease progression, and extended the survival. These results bring RNA interference therapy one step closer to its clinical application for treatment of chronic, devastating, and fatal CNS disorders.

microRNAs (miRNAs) are ~21 nucleotide non-coding small RNAs that are assembled into functional complexes containing Argonaute proteins (termed RNA-induced silencing complex (RISC)) which suppress target mRNA expression by directly inhibiting translation and/or enhancing mRNA destabilization. Here we report a straightforward, easy-to-use benchtop method to identify direct miRNA targets in vivo. We termed our strategy as miR-TRAP (miRNA Target RNA Affinity Purification). This method could be widely used to define miRNA targets in various disease models under physiological conditions.

Non-small cell lung cancer (NSCLC) remains the most common cause of cancer death worldwide due its resistance to chemotherapy and aggressive tumor growth. Polo-like kinase 1 (PLK1) is a serine-threonine protein kinase which is overexpressed in cancer cells, and plays a major role in regulating tumor growth. A number of PLK1 inhibitors are in clinical trial; however, poor tumor bioavailability and off-target effects limit their efficacy. Short-interfering-RNA (siRNA) holds promise as a class of therapeutics, which can selectively silence disease-causing genes. However, siRNA cannot enter cells without a delivery vehicle. Herein, we investigated whether RNAi-interfering nanoparticles could deliver siRNA to NSCLC cells and silence PLK1 expression in vitro and in vivo. iNOP-7 was non-toxic, and delivered siRNA with high efficiency to NSCLC cells. iNOP-7-PLK1 siRNA silenced PLK1 expression and reduced NSCLC growth in vitro. Notably, iNOP-7 delivered siRNA to orthotopic lung tumors in mice, and administration of iNOP-7-PLK1 siRNA reduced lung tumor burden. These novel data show that iNOP-7 can deliver siRNA against PLK1 to NSCLC cells, and decrease cell proliferation both in vitro and in vivo. iNOP-7-PLK1 siRNA may provide a novel therapeutic strategy for the treatment of NSCLC as well as other cancers which aberrantly express this gene.

A sphere-type fully substituted oligosaccharide-β-alanine-poly(lysine) dendrimer having a sharp molecular weight distribution was synthesized. Sphere-type poly(lysine) dendrimers were prepared using 1,4-diaminobutane as an initiator core and N,N′-bis(tert-butyloxycarbonyl)-L-lysine as a branching unit. β-Alanine was bound to the poly(lysine) dendrimer generation 3 to form β-alanine-poly(lysine) dendrimer generation 3, which has 16 terminal amino groups on its surface. A series of sphere-type oligosaccharide-β-alanine-poly(lysine) dendrimers were obtained by binding such an oligosaccharide as maltose, lactose, cellobiose, maltotriose, or a mixture of lactose and maltose to the surface of the β-alanine-poly(lysine) dendrimer scaffolding by reductive amination using the borane-pyridine complex. Oligosaccharide-β-alanine-poly(lysine) dendrimers having 32 oligosaccharide residues were obtained in high yields. NMR and MALDI-TOF mass measurements revealed that the oligosaccharide-polypeptide dendrimers have a monodispersed molecular weight distribution, the molecular weight of which was 13 418.36, 13 472.50, and 13 507.28 g/mol for cellobiose, maltose, and lactose, respectively, indicating that a complete substitution of the amino group by the oligosaccharide occurred.

Single-walled carbon nanotubes (SWNT) have unique electronic, mechanical, and structural properties as well as chemical stability that make them ideal nanomaterials for applications in materials science and medicine. Here we report the design and creation of a novel strategy for functionalizing SWNT to systemically silence a target gene in mice by delivering siRNA at doses <1 mg/Kg. SWNT were functionalized with lipids and natural amino acid-based dendrimers (TOT) and complexed to siRNA. Our model study of the silencing efficiency of the TOT-siRNA complex showed that in mice injected at 0.96 mg/kg, an endogenous gene for apoliproprotein B (ApoB) was silenced in liver, plasma levels of ApoB decreased, and total plasma cholesterol decreased. TOTsiRNA treatment was non-toxic and did not induce an immune response. Most (80%) of the RNA trigger molecules assembled with TOT were cleared from the body 48 h after injection, suggesting that the nanotubes did not cause siRNA aggregation or inhibit biodegradation and drug clearance in vivo. These results provide the first evidence that nanotubes can be functionalized with lipids and amino acids to systemically deliver siRNA. This new technology cannot only be used for systemic RNAi, but may also be used to deliver other drugs in vivo.