Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A new way to fight cancer: the silver shield

02.04.2008
Instead of a silver bullet to kill cancer cells, USC biologists discover a way to protect all other cells against chemotherapy; experts call the animal study a major advance in cancer research

Fasting for two days protects healthy cells against chemotherapy, according to a study appearing online the week of Mar. 31 in PNAS Early Edition.

Mice given a high dose of chemotherapy after fasting continued to thrive. The same dose killed half the normally fed mice and caused lasting weight and energy loss in the survivors.

The chemotherapy worked as intended on cancer, extending the lifespan of mice injected with aggressive human tumors, reported a group led by Valter Longo of the University of Southern California.

Test tube experiments with human cells confirmed the differential resistance of normal and cancer cells to chemotherapy after a short period of starvation.

Making chemotherapy more selective has been a top cancer research goal for decades. Oncologists could control cancers much better, and even cure some, if chemotherapy were not so toxic to the rest of the body.

Experts described the study as one of a kind.

“This is a very important paper. It defines a novel concept in cancer biology,” said cancer researcher Pinchas Cohen, professor and chief of pediatric endocrinology at the University of California, Los Angeles.

“In theory, it opens up new treatment approaches that will allow higher doses of chemotherapy. It’s a direction that’s worth pursuing in clinical trials in humans.”

Felipe Sierra, director of the Biology of Aging Program at the National Institute on Aging, said: “This is not just one more anti-cancer treatment that attacks the cancer cells. To me, that’s an important conceptual difference.”

Sierra was referring to decades of efforts by thousands of researchers working on “targeted delivery” of drugs to cancer cells. Study leader Longo focused instead on protecting all the other cells.

Sierra added that progress in cancer care has made patients more resilient and able to tolerate fasting, should clinical trials confirm its usefulness.

“We have passed the stage where patients arrive at the clinic in an emaciated state. Not eating for two days is not the end of the world,” Sierra said.

“This could have applicability in maybe a majority of patients,” said David Quinn, a practicing oncologist and medical director of USC Norris Hospital and Clinics. He predicted that many oncology groups would be eager to test the Longo group’s findings, and advised patients to look for a clinical trial near home.

Longo, an anti-aging researcher who holds joint appointments in gerontology and biological sciences at USC, said that the idea of protecting healthy cells from chemotherapy may have seemed impractical to cancer researchers, because the body has many different cells that respond differently to many drugs.

“It was almost like an idea that was not even worth pursuing. In fact it had to come from the anti-aging field, because that’s what we focus on: protecting all cells at once,” Longo said.

“What really was missing was a perspective of someone from the aging field to give this field a boost,” UCLA’s Cohen said.

The idea for the study came from the Longo group’s previous research on aging in cellular systems, primarily lowly baker’s yeast.

About five years ago, Longo was thinking about the genetic pathways involved both in the starvation response and in mammalian tumors.

When the pathways are silenced, starved cells go into what Longo calls a maintenance mode characterized by extreme resistance to stresses. In essence the cells are waiting out the lean period, much like hibernating animals.

But tumors by definition disobey orders to stop growing because the same genetic pathways are stuck in an “on” mode.

That could mean, Longo realized, that the starvation response might differentiate normal and cancer cells by their stress resistance, and that healthy cells might withstand much more chemotherapy than cancer cells.

The shield for healthy cells does not need to be perfect, Longo said. What matters is the difference in stress resistance between healthy and cancerous cells.

During the study, conducted both at USC and in the laboratory of Lizzia Raffaghello at Gaslini Children’s Hospital in Genoa, Italy, the researchers found that current chemotherapy drugs kill as many healthy mammalian cells as cancer cells.

“(But) we reached a two to five-fold difference between normal and cancer cells, including human cells in culture. More importantly, we consistently showed that mice were highly protected while cancer cells remained sensitive,” Longo said.

If healthy human cells were just twice as resistant as cancer cells, oncologists could increase the dose or frequency of chemotherapy.

“We were able to reach a 1,000-fold differential resistance using a tumor model in baker’s yeast. If we get to just a 10-20 fold differential toxicity with human metastatic cancers, all of a sudden it’s a completely different game against cancer,” Longo said.

“Now we need to spend a lot of time talking to clinical oncologists to decide how to best proceed in the human studies.”

Edith Gralla, a research professor of chemistry at UCLA, said: “It is the sort of opposite of the magic bullet. It’s the magic shield.”

Carl Marziali | EurekAlert!
Further information:
http://www.usc.edu

More articles from Health and Medicine:

nachricht Researchers release the brakes on the immune system
18.10.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht Norovirus evades immune system by hiding out in rare gut cells
12.10.2017 | University of Pennsylvania School of Medicine

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Osaka university researchers make the slipperiest surfaces adhesive

18.10.2017 | Materials Sciences

Space radiation won't stop NASA's human exploration

18.10.2017 | Physics and Astronomy

Los Alamos researchers and supercomputers help interpret the latest LIGO findings

18.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>