Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Findings Point to an “Off Switch” for Drug Resistance in Cancer

22.10.2014

Salk research indicates a potential mechanism for cancer cells’ adaptability.

Like a colony of bacteria or species of animals, cancer cells within a tumor must evolve to survive. A dose of chemotherapy may kill hundreds of thousands of cancer cells, for example, but a single cell with a unique mutation can survive and quickly generate a new batch of drug-resistant cells, making cancer hard to combat.


Salk Institute

From left: Yelena Dayn, Fernando Lopez-Diaz, Beverly Emerson

Now, scientists at the Salk Institute have uncovered details about how cancer is able to become drug resistant over time, a phenomenon that occurs because cancer cells within the same tumor aren’t identical—the cells have slight genetic variation, or diversity. The new work, published October 20 in PNAS, shows how variations in breast cancer cells’ RNA, the molecule that decodes genes and produces proteins, helps the cancer to evolve more quickly than previously thought. These new findings may potentially point to a “switch” to turn off this diversity—and thereby drug resistance—in cancer cells.

“It’s an inherent property of nature that in a community—whether it is people, bacteria or cells—a small number of members will likely survive different types of unanticipated environmental stress by maintaining diversity among its members,” says the senior author of the new work, Beverly Emerson, professor of Salk’s Regulatory Biology Laboratory and holder of the Edwin K. Hunter Chair. “Cancer co-ops this diversification strategy to foster drug resistance.”

Instead of looking at a single gene or pathway to target with cancer therapies, lead author Fernando Lopez-Diaz, Salk staff scientist, and the team aim to uncover the diversification “switch” by which cancer cells replicate but vary slightly from one another. Turning off this cellular process would strip cancer’s ability to survive drug treatment.

“Cancer isn’t one cell but it’s an ecosystem, a community of cells,” says Emerson. “This study begins the groundwork for potentially finding a way to understand and dial back cell diversity and adaptability during chemotherapy to decrease drug resistance.”

To uncover how groups of cancer cells achieve functional diversity (through RNA) to survive chemotherapy, Lopez-Diaz dosed dishes of human pre-cancer and metastatic breast cancer cells with the cancer drug paclitaxel for a week and then removed the drug for a few weeks, mimicking the treatment cycle for a cancer patient. Surviving cells—usually one or two out of millions—began to repopulate but with subtle changes in their RNA, presumably enabling them to survive future doses of the cancer drug.

By pushing the boundaries of bioinformatics, a collaboration led by Mei-Chong Wendy Lee and Nader Pourmand at the University of California, Santa Cruz charted more than 80,000 pieces of RNA per new cancer cell—typically, single-cell studies by other approaches look at hundreds or so RNA pieces to distinguish fairly different cells from one another. This unusually thorough list helped the researchers tease out subtle differences between generations of same cancer cells treated with chemotherapy and chart how the cancer cell community increased diversity among its members through RNA.

“We found an overwhelming return to diversity after chemotherapy treatment that couldn’t be explained by expected mechanisms,” says Lopez-Diaz. “There is something else going on here, a ‘philosopher’s stone’ to cancer cell diversity that we now know to look for.”

And when the team analyzed the gene expression profiles of the surviving cancer cell line, they were again surprised. “We thought they’d look like stressed cells with a few changes,” says Emerson. “Instead, after a few population doublings they go back to the normal gene expression pattern and rapidly reacquired drug sensitivity.” This adaptive behavior, Emerson speculates, lets the group of cancer cells prepare for the next unanticipated threat.

Another intriguing finding of the paper was that a high percentage of precancerous cells that underwent chemotherapy survived and proliferated, more so than either normal or cancerous cells. This led the pre-cancer cells to become more drug tolerant once they became a tumor. “The pre-cancer cells, when exposed to chemotherapy, evolved much faster and create a more drug-resistant state,” says Lopez-Diaz. “This and other findings can now be explored into greater detail using the knowledge and perspective we have gained here.”

Authors of the work include Beverly M. Emerson, Fernando J. Lopez-Diaz and Yelena Dayn at the Salk Institute; Nader Pourmand, Mei-Chong Wendy Lee, Shahid Yar Khan, Muhammad Akram Tariq, Amie J. Radenbaugh, and Hyunsung John Kim of the University of California, Santa Cruz; and Charles Joseph Vaske of Five3 Genomics.

Funding for the work includes support from the National Institutes of Health, the Chambers Medical Foundation, the GemCon Family Foundation and the Olive Tupper Foundation.

About the Salk Institute for Biological Studies: 
The Salk Institute for Biological Studies is one of the world's preeminent basic research institutions, where internationally renowned faculty probes fundamental life science questions in a unique, collaborative, and creative environment. Focused both on discovery and on mentoring future generations of researchers, Salk scientists make groundbreaking contributions to our understanding of cancer, aging, Alzheimer's, diabetes and infectious diseases by studying neuroscience, genetics, cell and plant biology, and related disciplines.

Faculty achievements have been recognized with numerous honors, including Nobel Prizes and memberships in the National Academy of Sciences. Founded in 1960 by polio vaccine pioneer Jonas Salk, MD, the Institute is an independent nonprofit organization and architectural landmark.

Salk Communications | newswise
Further information:
http://www.salk.edu

More articles from Life Sciences:

nachricht Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute

nachricht Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>