In a study available online and appearing in the April 12 edition of the journal Nature, researchers at UT Southwestern Medical Center describe how they used a library of small RNA molecules — the first used by a university research center — to identify the genes.
“Chemotherapy is a very blunt instrument,” he said. “It makes people sick, and its effects are very inconsistent. Identifying genes that make chemotherapy drugs more potent at lower doses is a first step toward alleviating these effects in patients.”
The current study tested only isolated cancer cells, so further studies will be needed to determine whether blocking the genes in living animals has the same effect.
The findings were made possible because of a technology that allows scientists to rapidly test how cells react when a given gene is turned off, or “silenced.” The so-called high-throughput employs a series of small plastic dishes, each with 96 wells. Using a robot, researchers place small bits of RNA that can block the function of one gene into each well on the plate. Next, non-small-cell lung cancer cells are placed in each well with the RNA.
The tiny bits of RNA used are called small interfering RNA, or siRNA. In this experiment, four siRNAs targeting a single gene were placed in each well. Overall, the researchers used 84,508 different siRNAs.
Next, the drug paclitaxel was added to each well for two days. By examining the survival of the cells in each well, the researchers determined which genes were involved in affecting the cells’ sensitivity to the drug.
All told, the experiment took more than 150,000 individual pipetting steps over seven weeks to test the drug.
The researchers then re-tested the six genes that showed the most dramatic effect with paclitaxel and tried the same test using the chemotherapy drugs vinorelbine (Navelbine) and gemcitabine (Gemzar), but the results were not as dramatic as those seen for paclitaxel. “Our studies using additional drugs indicate that the genes we uncovered are highly specific for paxlitaxel,” said Dr. Angelique Whitehurst, postdoctoral researcher in cell biology and lead author of the study.
“Being able to do this in human cells, and being able to do it fast — this is very powerful,” Dr. White said. “The idea of the screen was to be able to take advantage of the new generation of technology to silence any gene we want. That’s the power of a genome-wide screen — you go in without any expectations and let the data tell you what’s important.”
The siRNA library was developed by Dharmacon Pharmaceuticals and is commercially available. UT Southwestern is the first academic research institution to publish a study using the library, Dr. White said.
Other UT Southwestern researchers involved in the study were Brian Bodemann, medical and graduate student; Jessica Cardenas, student research assistant; Dr. Luc Girard, assistant professor of pharmacology in the Nancy B. and Jake L. Hamon Center for Therapeutic Oncology Research; Dr. Michael Peyton, research scientist in the Hamon Center; Dr. John Minna, professor of internal medicine and director of the Hamon Center; Dr. Carolyn Michnoff, former instructor of biochemistry; Dr. Weihua Hao, software systems specialist in biochemistry; Dr. Michael Roth, professor of biochemistry; and Dr. Xian-Jin Xie, associate professor of clinical sciences. Dr. Deborah Ferguson of Reata Pharmaceuticals also contributed to the study.
The work was supported by the National Cancer Institute, The Robert A. Welch Foundation, Susan G. Komen Foundation, and the Department of Defense.
Aline McKenzie | EurekAlert!
Team discovers how bacteria exploit a chink in the body's armor
20.01.2017 | University of Illinois at Urbana-Champaign
Rabies viruses reveal wiring in transparent brains
19.01.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences