Combination Chemotherapy of L1210 Tumors in Mice with Pretubulysin and Methotrexate Lipo-Oligomer Nanoparticles

Binary Nanodrug-Delivery System Designed for Leukemia Therapy: Aptamer- and Transferrin-Codecorated Daunorubicin- and Luteolin-Coloaded Nanoparticles

Objective

This study aimed to develop a binary nanodrug-delivery system decorated with aptamers (APs) and transferrin (Tf) and loaded with daunorubicin (Drn) and luteolin (Lut) for the treatment of leukemia.

Methods

Oligonucleotide AP- and Tf-contaiing ligands were designed and synthesized separately. AP-decorated Drn-loaded nanoparticles (AP-Drn NPs) and Tf-Lut NPs were prepared by self-assembly. An AP- and Tf-codecorated Drn- and Lut-coloaded nanodrug-delivery system (AP/Tf-Drn/Lut NPs) was prepared by self-assembly of AP-Drn NPs and Tf-Lut NPs. In vitro and in vivo efficiency of the system was evaluated on leukemia cell line and cell-bearing mouse model in comparison with single ligand-decorated, single drug-loaded and free-drug formulations.

Results

AP/Tf-Drn/Lut NPs were spherical and nanosized (187.3±5.3 nm) and loaded with about 85% of drugs. In vitro cytotoxicity of AP/Tf-Drn/Lut NPs was remarkably higher than single ligand-decorated ones. Double drug-loaded AP/Tf-Drn/Lut NPs exhibited higher tumor-cell inhibition than single drug-loaded ones, which showed a synergic effect of the two drugs. AP/Tf-Drn/Lut NPs achieved the most efficient antileukemic activity and absence of toxicity in vivo.

Conclusion

The present study showed that AP/Tf-Drn/Lut NPs are a promising drug-delivery system for targeted treatment of leukemia, due to the synergic effect of the two drugs in this system. The limitations of this system include stability during large-scale production and application from bench to bedside.

Molecular recognition-driven supramolecular nanoassembly of a hydrophobic uracil prodrug and hydrophilic cytarabine for precise combination treatment of solid and non-solid tumors

Combination chemotherapy has shown distinct therapeutic advantages over monotherapy in clinical cancer treatment, especially for two chemotherapeutic drugs with different mechanisms of action. However, how to achieve efficient co-delivery of two or more drugs with different physicochemical and pharmacokinetic properties for synergistic therapy is still a huge challenge. In particular, it is even more difficult to efficiently co-deliver a hydrophilic drug and a hydrophobic drug into one nanosystem. Herein, inspired by the natural Watson-Crick base pair molecular recognition in nucleic acids, a reduction-sensitive uracil prodrug of doxorubicin (U-SS-DOX) is synthesized and performs supramolecular co-assembly with cytarabine (Ara-C). Interestingly, the hydrophilic Ara-C molecules could readily co-assemble with U-SS-DOX, and multiple hydrogen bonds are found in the nanoassembly with an ultra-high drug loading rate. Moreover, 1,1'-dioctadecyl-3,3,3',3'-tetramethylindotricarbocyanine iodide (DiR) is used as a fluorescent probe to investigate the pharmacokinetics of U : C NPs. It turns out that the DiR-labeled U : C NPs significantly prolong the systemic circulation and promote the tumor-specific accumulation of DiR when compared with DiR solution. Furthermore, the supramolecular nanoassembly demonstrates potent satisfactory therapeutic effects in treating both solid and non-solid tumors in vivo. This study provides a novel molecular co-assembly nanoplatform for efficient co-delivery of hydrophilic and hydrophobic drugs.

Artificial peptides for antitumoral siRNA delivery

Intracellular delivery has been critical for the success of siRNA and related therapeutic nucleic acids. Improvement of delivery carriers will positively influence the efficacy of future nanomedicines. Our strategy for optimizing siRNA nanocarriers focuses on a bioinspired sequence-defined process including (i) identification of artificial amino acids active in specific delivery steps, (ii) assembly into defined sequences by solid phase-assisted synthesis (SPS), and (iii) screening for siRNA delivery, selection of top candidates and understanding structure-activity relations, followed by (iv) sequence variation for the next round of carrier selection. In the current review, our experience with this artificial peptide evolution in tumor-directed siRNA delivery is addressed. The medium-sized oligoaminoamides show better biological compatibility and can be functionalized to meet the requirements of siRNA delivery, such as formation of stable nanoparticles, shielding against proteins in the bloodstream, targeting into tumor tissue, and intracellular siRNA release in bioactive form.

Optimizing synthetic nucleic acid and protein nanocarriers: The chemical evolution approach

Optimizing synthetic nanocarriers is like searching for a needle in a haystack. How to find the most suitable carrier for intracellular delivery of a specified macromolecular nanoagent for a given disease target location? Here, we review different synthetic 'chemical evolution' strategies that have been pursued. Libraries of nanocarriers have been generated either by unbiased combinatorial chemistry or by variation and novel combination of known functional delivery elements. As in natural evolution, definition of nanocarriers as sequences, as barcode or design principle, may fuel chemical evolution. Screening in appropriate test system may not only provide delivery candidates, but also a refined understanding of cellular delivery including novel, unpredictable mechanisms. Combined with rational design and computational algorithms, candidates can be further optimized in subsequent evolution cycles into nanocarriers with improved safety and efficacy. Optimization of nanocarriers differs for various cargos, as illustrated for plasmid DNA, siRNA, mRNA, proteins, or genome-editing nucleases.

Delivery of Cas9/sgRNA Ribonucleoprotein Complexes via Hydroxystearyl Oligoamino Amides

The programmable endonuclease activity and simple usage of CRISPR/Cas9 have revolutionized the field of genome editing. The binding of single guide RNA (sgRNA) by the Cas9 protein results in the formation of negatively charged ribonucleoprotein (RNP) complexes. The presence of this functional complex inside cells is imperative for the intended specific genome modifications. The direct intracellular delivery of Cas9/sgRNA RNP complexes is of great advantage. In this work, a compound library of sequence-defined oligo(ethylenamino) amides containing structural motifs for stable nanoparticle formation, cellular uptake, and endosomal release was used for the screening and development of suitable Cas9 RNP delivery vehicles. Lipid-containing oligoaminoamides (lipo-OAAs) were identified as the most efficient carriers for intracellular Cas9/sgRNA delivery and gene disruption. Fluorescence correlation spectroscopy measurements indicated that the lipo-OAAs only interact with sgRNA-loaded Cas9 protein, which suggests exclusive ionic interaction with the negatively charged RNPs. The type of contained fatty acid turned out to have a critical impact on the knock out efficiency: the presence of one hydroxy group in the fatty acid dramatically changes the properties and performance of the resulting Cas9/sgRNA lipo-OAA complexes. The lipo-OAA-containing hydroxy-stearic acid (OHSteA) was superior to the analogues with saturated or unsaturated fatty acids without hydroxylation; it formed smaller and more defined nanoparticles with Cas9/sgRNA and improved the cellular uptake and endosomal release, which altogether resulted in an increased nuclear association and the highest gene knock out levels. The efficient and adaptable delivery platform has high potential for the future development of therapeutics based on precise genome modifications.