Modular degradable dendrimers enable small RNAs to extend survival in an aggressive liver cancer model

Zhou, Kejin; Nguyen, Liem H.; Miller, Jason B.; Yan, Yunfeng; Kos, Petra; Xiong, Hu; Li, Lin; Hao, Jing; Minnig, Jonathan T.; Zhu, Min; Siegwart, Daniel J.

doi:10.1073/pnas.1520756113

Cited by 144 publications

(144 citation statements)

References 45 publications

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“…The EC 50 value was approximately 0.03 mg/kg, which is competitive with other potent nanoparticles that deliver siRNA to the liver. 14,19,21,29 Control LNPs delivering siGFP did not incur FVII knockdown, suggesting that the knockdown observed was not due to LNP toxicity-related effects. Furthermore, there was no significant effect on mouse body weight, suggesting low nanoparticle toxicity (Fig.…”

Section: O I10 Lnps Effectively Silenced Factor VII In Vivomentioning

confidence: 94%

“…2,14,15,20,21 Although our group and others have come to appreciate the importance of tertiary amines within intracellular delivery materials, structure function understanding generally has been limited to the alkyl-amines that are one of the two precursors to lipidoids. 5,21,28,29 The structural importance of the second precursor, the alkyl tail, has not yet been thoroughly investigated.…”

Section: Introductionmentioning

confidence: 99%

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Lipidoid Tail Structure Strongly Influences siRNA Delivery Activity

2016

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RNA interference therapeutics have been limited, in large part, by the lack of efficient, non-toxic, non-immunogenic delivery systems. Among previously established methods, lipidoid nanoparticles (LNPs) show particular promise in delivering siRNA to diverse cell and organ targets in vitro and in vivo. However, a better understanding of structure-function relationships is needed to facilitate broad translation to clinical applications. Here, we demonstrate the critical role of tail chemistry in conferring delivery efficacy to lipidoid molecules with three or four aliphatic tails. Tail length and structure significantly affected siRNA transfection in HeLa cells, with methacrylate (vs. acrylate) tails and tails containing ethers causing reductions in efficacy. Notably, we report a novel tail precursor, isodecyl acrylate, that conveyed marked siRNA delivery ability in vitro and in vivo. LNPs with isodecyl acrylate lipidoids uniformly induced greater than 90% gene silencing, both in vitro and in mice (hepatocytes), at 40 nM and 0.1 mg/ kg, respectively. Furthermore, we found that tail chemistry significantly influenced the surface pKa values of formulated LNPs, with tails that conferred higher pKa facilitating higher levels of gene knockdown. Together, these data underscore the importance of lipidoid tail structure and provide guidance for the development of next generation lipid nanoparticle siRNA delivery systems.

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Section: O I10 Lnps Effectively Silenced Factor VII In Vivomentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Lipidoid Tail Structure Strongly Influences siRNA Delivery Activity

2016

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“…Structure-activity analysis of a heat map showing luciferase silencing indicated that the area with lower MW (PE4K) and longer alkyl thiols (C12SH) and the area with higher MW (PE8K) and shorter alkyl thiols (C6SH and C10SH) were the most active. This suggests that, in addition to optimal cationic nature and pK a , effective siRNA delivery requires a balance between the polymer MW and hydrophobicity that relates to physical chain entanglement and intermolecular forces (23,35,39,44). The top-performing polymers show superior delivery activity over the commercial benchmark RNAiMax according to dose-response curves (SI Appendix, Fig.…”

Section: A Scalable Methods Enabled Synthesis Of Polyesters With Divermentioning

confidence: 99%

Functional polyesters enable selective siRNA delivery to lung cancer over matched normal cells

Yan

Liu

Xiong

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Conventional chemotherapeutics nonselectively kill all rapidly dividing cells, which produces numerous side effects. To address this challenge, we report the discovery of functional polyesters that are capable of delivering siRNA drugs selectively to lung cancer cells and not to normal lung cells. Selective polyplex nanoparticles (NPs) were identified by high-throughput library screening on a unique pair of matched cancer/normal cell lines obtained from a single patient. Selective NPs promoted rapid endocytosis into HCC4017 cancer cells, but were arrested at the membrane of HBEC30-KT normal cells during the initial transfection period. When injected into tumor xenografts in mice, cancer-selective NPs were retained in tumors for over 1 wk, whereas nonselective NPs were cleared within hours. This translated to improved siRNA-mediated cancer cell apoptosis and significant suppression of tumor growth. Selective NPs were also able to mediate gene silencing in xenograft and orthotopic tumors via i.v. injection or aerosol inhalation, respectively. Importantly, this work highlights that different cells respond differentially to the same drug carrier, an important factor that should be considered in the design and evaluation of all NP carriers. Because no targeting ligands are required, these functional polyester NPs provide an exciting alternative approach for selective drug delivery to tumor cells that may improve efficacy and reduce adverse side effects of cancer therapies.

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“…[9, 28–31] Recently, Siegwart and coworkers utilized combinatorial synthesis to build new chemical classes of biodegradable dendrimer and polymer constructs that were incorporated as the cationic component of lipid nanoparticles. [32, 33] This combinatorial approach allowed for the rapid screening and narrowing of a large chemical space which produced lead compounds highly effective for both siRNA and miRNA delivery in vivo .…”

Section: Introductionmentioning

confidence: 99%

Combinatorial optimization of PEG architecture and hydrophobic content improves ternary siRNA polyplex stability, pharmacokinetics, and potency in vivo

Werfel

Jackson

Kavanaugh

et al. 2017

Journal of Controlled Release

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A rationally-designed library of ternary siRNA polyplexes was developed and screened for gene silencing efficacy in vitro and in vivo with the goal of overcoming both cell-level and systemic delivery barriers. [2-(dimethylamino)ethyl methacrylate] (DMAEMA) was homopolymerized or colpolymerized (50 mol% each) with butyl methacrylate (BMA) from a reversible addition – fragmentation chain transfer (RAFT) chain transfer agent, with and without pre-conjugation to polyethylene glycol (PEG). Both single block polymers were tested as core-forming units, and both PEGylated, diblock polymers were screened as corona-forming units. Ternary siRNA polyplexes were assembled with varied amounts and ratios of core-forming polymers to PEGylated corona-forming polymers. The impact of polymer composition/ratio, hydrophobe (BMA) placement, and surface PEGylation density was correlated to important outcomes such as polyplex size, stability, pH-dependent membrane disruptive activity, biocompatibility, and gene silencing efficiency. The lead formulation, DB4-PDB12, was optimally PEGylated not only to ensure colloidal stability (no change in size by DLS between 0 and 24 hr) and neutral surface charge (0.139 mV) but also to maintain higher cell uptake (>90% positive cells) than the most densely PEGylated particles. The DB4-PDB12 polyplexes also incorporated BMA in both the polyplex core- and corona-forming polymers, resulting in robust endosomolysis and in vitro siRNA silencing (~85% protein level knockdown) of the model gene luciferase across multiple cell types. Further, the DB4-PDB12 polyplexes exhibited greater stability, increased blood circulation time, reduced renal clearance, increased tumor biodistribution, and greater silencing of luciferase compared to our previously-optimized, binary parent formulation following intravenous (i.v.) delivery. This polyplex library approach enabled concomitant optimization of the composition and ratio of core- and corona-forming polymers (indirectly tuning PEGylation density) and identification of a ternary nanomedicine optimized to overcome important siRNA delivery barriers in vitro and in vivo.

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Modular degradable dendrimers enable small RNAs to extend survival in an aggressive liver cancer model

Cited by 144 publications

References 45 publications

Lipidoid Tail Structure Strongly Influences siRNA Delivery Activity

Lipidoid Tail Structure Strongly Influences siRNA Delivery Activity

Functional polyesters enable selective siRNA delivery to lung cancer over matched normal cells

Combinatorial optimization of PEG architecture and hydrophobic content improves ternary siRNA polyplex stability, pharmacokinetics, and potency in vivo

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