On Target: Therapeutic Opportunities of siRNAs and Antagomirs

On Target
Reported by
Don Monroe

Posted August 01, 2008


Over the past decade or so, researchers have begun to glimpse the rich framework of RNA-based regulatory mechanisms in cells. RNA interference and related mechanisms have already been extensively used as a tool to explore fundamental biological questions. Researchers—and pharmaceutical companies—have high hopes for their therapeutic use as well.

A June 10, 2008 meeting at the Academy addressed some aspects of these therapeutic opportunities. The symposium covered a wide range of topics that researchers should be aware of as they consider safe, practical, and effective delivery of oligonucleotides as drugs. Some talks focused tightly on the stability, targeting, and quantification of short interfering RNA (siRNA) delivery, while others addressed more generally the need to identify appropriate targets and avoid immune side effects. In many of these areas, the history of antisense technology, which largely failed to achieve comparably lofty goals, provides a cautionary tale, but also practical experience in delivering oligonucleotides.

Journal Articles

Ingo Röhl

Frauendorf C, Hausch F, Röhl I, et al. 2003. Internal 32P-labeling of L-deoxyoligonucleotides. Nucleic Acids Res. 31: e34. Full Text

Schoetzau T, Langner J, Moyroud E, et al. 2003. Modified nucleoside triphosphates: synthesis and applications for RNA in vitro selection. Nucleosides Nucleotides Nucleic Acids 22: 1293-1296.

Soutschek J, Akinc A, Bramlage B, et al. 2004. Therapeutic silencing of an endogenous gene by systemic administration of modified siRNAs. Nature 432: 173-178.

Zimmermann TS, Lee ACH, Akinc A, et al. 2006. RNAi-mediated gene silencing in non-human primates. Nature 441: 111-114.

Jan Krützfeldt

Elmén J, Lindow M, Schütz S, et al. 2008. LNA-mediated microRNA silencing in non-human primates. Nature 452: 896-899.

Esau C, Davis S, Murray SF, et al. 2006. miR-122 regulation of lipid metabolism revealed by in vivo antisense targeting. Cell Metab. 3: 87-98. Full Text

Krützfeldt J, Poy MN, Stoffel M. 2006. Strategies to determine the biological function of microRNAs. Nat. Genet. 38: Suppl: S14-19.

Krützfeldt J, Rajewsky N, Braich R, et al. 2005. Silencing of microRNAs in vivo with 'antagomirs'. Nature 438: 685-689.

Krützfeldt J, Kuwajima S, Braich R, et al. 2007. Specificity, duplex degradation and subcellular localization of antagomirs. Nucleic Acids Res. 35: 2885-2892. Full Text

Jost Seibler

Christoph T, Bahrenberg G, De Vry J, et al. 2008. Investigation of TRPV1 loss-of-function phenotypes in transgenic shRNA expressing and knockout mice. Mol. Cell. Neurosci. 37: 579-589.

Seibler J, Küter-Luks B, Kern H, et al. 2005. Single copy shRNA configuration for ubiquitous gene knockdown in mice. Nucleic Acids Res. 33: e67. Full Text

Seibler J, Kleinridders A, Küter-Luks B, et al. 2007. Reversible gene knockdown in mice using a tight, inducible shRNA expression system. Nucleic Acids Res. 35: e54. Full Text

Takai H, Wang RC, Takai KK, et al. 2007. Tel2 regulates the stability of PI3K-related protein kinases. Cell 131: 1248-59.

Philip Low

Zhang K, Wang Q, Xie Y, et al. 2008. Receptor-mediated delivery of siRNAs by tethered nucleic acid base-paired interactions. RNA 14: 577-583.

Low PS, Henne WA, Doorneweerd DD. 2008. Discovery and development of folic-acid-based receptor targeting for imaging and therapy of cancer and inflammatory diseases. Acc. Chem. Res. 41: 120-129.

Sega EI, Low PS. 2008. Tumor detection using folate receptor-targeted imaging agents. Cancer Metastasis Rev. in press.

Zhang K, Wang Q, Xie Y, et al. 2008. Receptor-mediated delivery of siRNAs by tethered nucleic acid base-paired interactions. RNA 14: 577-583.

Arthur Krieg

Forsbach A, Nemorin JG, Montino C, et al. 2008. Identification of RNA sequence motifs stimulating sequence-specific TLR8-dependent immune responses. J. Immunol. 180: 3729-3738.

Kleinman ME, Yamada K, Takeda A, et al. 2008. Sequence- and target-independent angiogenesis suppression by siRNA via TLR3. Nature 452: 591-597.

Krieg AM. 2008. Toll-like receptor 9 (TLR9) agonists in the treatment of cancer. Oncogene 27: 161-167.

John Lamb

Chen Y, Zhu J, Lum PY, et al. 2008. Variations in DNA elucidate molecular networks that cause disease. Nature 452: 429-435.

Emilsson V, Thorleifsson G, Zhang B, et al. 2008. Genetics of gene expression and its effect on disease. Nature 452: 423-428.

Schadt EE, Lamb J, Yang X, et al. 2005. An integrative genomics approach to infer causal associations between gene expression and disease. Nat. Genet. 37: 710-717.

Zhang B, Horvath S. 2005. A general framework for weighted gene co-expression network analysis. Stat. Appl. Genet. Mol. Biol. 4: Article 17.


Ingo Röhl, PhD

Roche Kulmbach
e-mail | web site | publications

Ingo Röhl studied chemistry at the University of Oldenburg (Germany) and did his Diplom thesis work in combinatorial organic chemistry. His PhD work was focused on the isolation and identification of new sex pheromones from marine invertebrates. After receiving his doctorate, Röhl became head of the analytical chemistry department at NOXXON Pharma AG in the beginning of 2001. He built up the analytical department and worked on new methods for quality control and biochemical characterization of aptamers containing the non-natural L-ribose sugar backbone, the so-called Spiegelmers.

In 2003 Röhl joined Alnylam Pharmaceuticals. His work has been published as part of several breakthrough RNAi publications over the past four years. Through the acquisition of Alnylam's German site in August 2007, Röhl is now heading the analytical department at the Roche RNA Center of Excellence. The main interest of his group is the development of new characterization methods for quality control and chemistry, manufacturing, and control (CMC) for siRNA therapeutics and for the drug metabolism and pharmacokinetics (DMPK) and biodistribution of RNA.

Jan Krützfeldt, MD

Swiss Federal Institute of Technology Zurich
e-mail | web site | publications

Jan Krützfeldt, received his MD from the Medical University of Lübeck in 1998, and did a residency studying insulin signaling at the University of Tübingen. In 2002 he joined the lab of Markus Stoffel at Rockefeller University exploring microRNA function in mice, and in 2007, he moved with Stoffel to the Institute Swiss Federal Institute of Technology Zurich, where he is part of a clinical fellowship program.

Jost Seibler, PhD

e-mail | web site | publications

Jost Seibler is the head of technology development and RNAi research at TaconicArtemis. He leads a group dedicated to the development of novel technologies for inducible expression and repression of genes, for targeted transgenesis and for mouse disease models. He has established and is responsible for the RNAi custom project group, and has contributed to the development of proprietary knockout systems and other key technologies. Before joining TaconicArtemis in March 2000 he worked at the National Research Center for Biotechnology in Braunschweig (GBF), where he developed recombinase-based technologies for genetic engineering of the ES cell genome, including a system for the efficient exchange of gene expression cassettes. He received his PhD in 1999 from the TU-Braunschweig.

Philip S. Low, PhD

Purdue University
Endocyte, Inc.
e-mail | web site | publications

Philip Low is the Ralph C. Corley Distinguished Professor of Chemistry at Purdue University. Low has published over 270 refereed articles on various topics, including: 1) structure and function of the human erythrocyte membrane, 2) signal transduction across plant plasma membranes, 3) design and development of receptor-targeted imaging and therapeutic agents for cancer and inflammatory diseases, and 4) design and development of receptor-targeted imaging and therapeutic agents for cancer and inflammatory diseases.

Low's research into receptor-targeted therapeutic and imaging agents has led to more than 30 U.S. patents/patents pending, and development of these patents has yielded 5 targeted drugs that are currently undergoing human clinical trials for kidney, ovarian, breast, lung, brain and endometrial cancers. He is founder of Endocyte Inc., which is developing treatments based on this last technology. He is also the recipient of numerous honors and awards.

Arthur M. Krieg, MD

Pfizer Research Technology Center
e-mail | web site | publications

Arthur Krieg is chief scientific officer of Pfizer's Research Technology Center. He was formerly CSO, executive vice president of research and development, and cofounder of Coley Pharmaceutical Group, prior to its acquisition and incorporation into Pfizer in 2008.

Krieg received his MD from Washington University in 1983, and he completed a residency in Internal Medicine at the University of Minnesota in 1986. He was a staff fellow at the NIH in the Arthritis Institute from 1986 to 1991, when he left to become an assistant professor in the Department of Internal Medicine at the University of Iowa. He was promoted to full professor in 1998.

Krieg was cofounder and coeditor of the journal Oligonucleotides until 2006, and is founding vice president of the Oligonucleotide Therapeutics Society. He is a board-certified rheumatologist and a fellow of the American College of Rheumatology. He has published more than 200 scientific papers and is co-inventor on 12 issued and 78 pending U.S. patents covering CpG technology. His 1995 Nature paper reporting the discovery of the CpG motif has been cited more than 1200 times.

John R. Lamb, PhD

Rosetta Inpharmatics
e-mail | web site | publications

John Lamb is scientific director in the Genetics group at Rosetta Inpharmatics in Seattle. Lamb currently heads the group applying systems biology approaches to oncology, describing the key variables that drive tumor specific expression and behavior and relating this to treatment outcome. Lamb has also led teams in the identification and development of targets using population-based systems biology approaches for a range of disease areas including, diabetes, obesity, cardiovascular disease, asthma, and cancer.

Thomas Tuschl, PhD (organizer)

The Rockefeller University
e-mail | web site | publications

Thomas Tuschl received a diploma in chemistry from the University of Regensburg in Germany and a PhD in chemistry from the Max Planck Institute for Experimental Medicine and the University of Regensburg. He is associate professor and head of the laboratory for RNA molecular biology at The Rockefeller University. He has received the Wiley Prize in the Biomedical Sciences from the Wiley Foundation and the 2003 AAAS Newcomb Cleveland Prize for an outstanding paper in Science.

Don Monroe

Don Monroe is a science writer based in Murray Hill, New Jersey. After getting a PhD in physics from MIT, he spent more than fifteen years doing research in physics and electronics technology at Bell Labs. He writes on physics, technology, and biology.