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LAKE OSWEGO, OR, United States

Ngamcherdtrakul W.,Oregon Health And Science University | Morry J.,Oregon Health And Science University | Gu S.,Oregon Health And Science University | Castro D.J.,Oregon Health And Science University | And 11 more authors.
Advanced Functional Materials

In vivo delivery of siRNAs designed to inhibit genes important in cancer and other diseases continues to be an important biomedical goal. A new nanoparticle construct that is engineered for efficient delivery of siRNA to tumors is now described. The construct comprises a 47-nm mesoporous silica nanoparticle core coated with a crosslinked polyethyleneimine-polyethyleneglycol copolymer, carrying siRNA against the human epidermal growth factor receptor type 2 (HER2) oncogene, and coupled to the anti-HER2 monoclonal antibody (trastuzumab). The construct is engineered to increase siRNA blood half-life, enhance tumor-specific cellular uptake, and maximize siRNA knockdown efficacy. The optimized anti-HER2 nanoparticles produce apoptotic death in HER2 positive (HER2+) breast cancer cells grown in vitro, but not in HER2 negative (HER2-) cells. One dose of the siHER2-nanoparticles reduces HER2 protein levels by 60% in trastuzumab-resistant HCC1954 xenografts. Administration of multiple intravenous doses over 3 weeks significantly inhibits tumor growth (p < 0.004). The siHER2-nanoparticles have an excellent safety profile in terms of blood compatibility and low cytokine induction, when exposed to human peripheral blood mononuclear cells. The construct can be produced with high batch-to-batch reproducibility and the production methods are suitable for large-scale production. These results suggest that this siHER2-nanoparticle is ready for clinical evaluation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Morry J.,Oregon Health And Science University | Ngamcherdtrakul W.,Oregon Health And Science University | Gu S.,Oregon Health And Science University | Goodyear S.M.,Oregon Health And Science University | And 6 more authors.

Fibrotic diseases such as scleroderma have been linked to increased oxidative stress and upregulation of pro-fibrotic genes. Recent work suggests a role of NADPH oxidase 4 (NOX4) and heat shock protein 47 (HSP47) in inducing excessive collagen synthesis, leading to fibrotic diseases. Herein, we elucidate the relationship between NOX4 and HSP47 in fibrogenesis and propose to modulate them altogether as a new strategy to treat fibrosis. We developed a nanoparticle platform consisting of polyethylenimine (PEI) and polyethylene glycol (PEG) coating on a 50-nm mesoporous silica nanoparticle (MSNP) core. The nanoparticles effectively delivered small interfering RNA (siRNA) targeting HSP47 (siHSP47) in an invitro model of fibrosis based on TGF-β stimulated fibroblasts. The MSNP core also imparted an antioxidant property by scavenging reactive oxygen species (ROS) and subsequently reducing NOX4 levels in the invitro fibrogenesis model. The nanoparticle was far superior to n-acetyl cysteine (NAC) at modulating pro-fibrotic markers. Invivo evaluation was performed in a bleomycin-induced scleroderma mouse model, which shares many similarities to human scleroderma disease. Intradermal administration of siHSP47-nanoparticles effectively reduced HSP47 protein expression in skin to normal level. In addition, the antioxidant MSNP also played a prominent role in reducing the pro-fibrotic markers, NOX4, alpha smooth muscle actin (α-SMA), and collagen type I (COL I), as well as skin thickness of the mice. © 2015 Elsevier Ltd. Source

Gu S.,Oregon Health And Science University | Hu Z.,Oregon Health And Science University | Ngamcherdtrakul W.,Oregon Health And Science University | Ngamcherdtrakul W.,Pdx Pharmaceuticals, Llc | And 7 more authors.

HER2 is overexpressed in about 20% of breast cancers and contributes to poor prognosis. Unfortunately, a large fraction of patients have primary or acquired resistance to the HER2-targeted therapy trastuzumab, thus a multi-drug combination is utilized in the clinic, putting significant burden on patients. We systematically identified an optimal HER2 siRNA from 76 potential sequences and demonstrated its utility in overcoming intrinsic and acquired resistance to trastuzumab and lapatinib in 18 HER2-positive cancer cell lines. We provided evidence that the drug-resistant cancer maintains dependence on HER2 for survival. Importantly, cell lines did not readily develop resistance following extended treatment with HER2 siRNA. Using our recently developed nanoparticle platform, systemic delivery of HER2 siRNA to trastuzumab-resistant tumors resulted in significant growth inhibition. Moreover, the optimal HER2 siRNA could also silence an exon 16 skipped HER2 splice variant reported to be highly oncogenic and linked to trastuzumab resistance. Source

Ngamcherdtrakul W.,Oregon Health And Science University | Ngamcherdtrakul W.,Pdx Pharmaceuticals, Llc | Castro D.J.,Oregon Health And Science University | Castro D.J.,Pdx Pharmaceuticals, Llc | And 6 more authors.
Cancer Treatment Reviews

This Review discusses the various types of non-coding oligonucleotides, which have garnered extensive interest as new alternatives for targeted cancer therapies over small molecule inhibitors and monoclonal antibodies. These oligonucleotides can target any hallmark of cancer, no longer limited to so-called "druggable" targets. Thus, any identified gene that plays a key role in cancer progression or drug resistance can be exploited with oligonucleotides. Among them, small-interfering RNAs (siRNAs) are frequently utilized for gene silencing due to the robust and well established mechanism of RNA interference. Despite promising advantages, clinical translation of siRNAs is hindered by the lack of effective delivery platforms. This Review provides general criteria and consideration of nanoparticle development for systemic siRNA delivery. Different classes of nanoparticle candidates for siRNA delivery are discussed, and the progress in clinical trials for systemic cancer treatment is reviewed. Lastly, this Review presents HER2 (human epidermal growth factor receptor type 2)-positive breast cancer as one example that could benefit significantly from siRNA technology. How siRNA-based therapeutics can overcome cancer resistance to such therapies is discussed. © 2016 Elsevier Ltd. Source

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