Two tumor-suppressing genes given intravenously reduced cancer separately but had their most powerful effect when administered together, cutting the number of tumors per mouse by 75 percent and the weight of tumors by 80 percent.
"In cancer treatment we have combination chemotherapy, and we also combine different modes of therapy - surgery, radiation and chemotherapy. Now you've got the possibility of combined targeted gene therapy," said Jack Roth, M.D., professor and chair of the M. D. Anderson Department of Thoracic and Cardiovascular Surgery and a senior researcher on the project.
The genes wrapped in the nanoparticles were p53, a well-known tumor suppressor that works by causing defective cells to commit suicide and is often shut down or defective in cancer cells, and FUS1, a tumor-suppressor discovered by the research group that is deficient in most human lung cancers. Each nanoparticle carried one of the two genes.
The Cancer Research paper reports that FUS1 works with p53 to force the lung cancer cells to kill themselves - a process known as apoptosis.
Further analysis showed that the combination achieved greater cell suicide because FUS1 suppresses a gene that expresses a protein known to rapidly degrade p53, says senior author Lin Ji, Ph.D., M. D. Anderson associate professor of thoracic and cardiovascular surgery.
The FUS1/p53 combination also activates a cell suicide pathway based in the cells' mitochondria, their energy powerhouse.
Lab experiments first showed that the gene combination cut the number of viable cells in four lines of human non-small cell lung cancer by 70 to 80 percent 48 hours after treatment while leaving a control group of normal cells unaffected. The cancer cell lines treated with the gene combination had 2 to 3 times more cells killed by apoptosis than either gene nanoparticle had individually. The research team then confirmed these findings in the mouse studies.
The nanoparticle delivery system, which the researchers have used for years, consists of a plasmid gene expression cassette loaded with DNA that encodes either the p53 or the FUS1 protein. This is wrapped tightly in a form of cholesterol to protect it from the body's defense mechanisms. "You can't deliver naked DNA for cancer therapy," Ji says.
The nanoparticles accumulate mainly in the lungs, particularly in the tumors, Ji says. The positively charged nanoparticles are delivered to the negatively charged cancer cell membrane and taken into the cell, where the genes repeatedly express either p53 or FUS1 tumor-suppressing proteins.
Roth expects the research team to advance combination therapies to clinical trials in the coming years, either of genes or of genes with other biologic or chemotherapy agents.
"We certainly hope this approach will be more effective but we also think it's likely to be much less toxic, with fewer side effects, than other types of combined cancer therapy," Roth says. "These genes don't have much effect on normal tissue or normal cells when they are overexpressed. It's really just cancer cells where they seem to have their effect. Ultimately, the usefulness of this approach has to be proven in clinical trials."
Scott Merville | EurekAlert!
Plasmonic biosensors enable development of new easy-to-use health tests
14.12.2017 | Aalto University
ASU scientists develop new, rapid pipeline for antimicrobials
14.12.2017 | Arizona State University
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
14.12.2017 | Health and Medicine
14.12.2017 | Physics and Astronomy
14.12.2017 | Life Sciences