Researchers use nanoparticles to shrink tumors in mice

July 9, 2010 By Jennifer Marcus
Researchers use nanoparticles to shrink tumors in mice
Fluorescence shows accumulation of nanoparticles in tumor. A dorsal view of a mouse showing accumulation of nanoparticles in a tumor four hours after intravenous administration. Bright fluorescence is observed predominantly in the tumor.

(PhysOrg.com) -- The application of nanotechnology in the field of drug delivery has attracted much attention in recent years. In cancer research, nanotechnology holds great promise for the development of targeted, localized delivery of anticancer drugs, in which only cancer cells are affected.

Such targeted-therapy methods would represent a major advance over current chemotherapy, in which anticancer drugs are distributed throughout the body, attacking healthy cells along with and causing a number of adverse side effects.

By carrying out comprehensive studies on with human tumors, UCLA scientists have obtained results that move the research one step closer to this goal. In a paper published July 8 in the journal Small, researchers at UCLA's California Institute and Jonsson Comprehensive Cancer Center demonstrate that mesoporous silica nanoparticles (MSNs), tiny particles with thousands of pores, can store and deliver chemotherapeutic drugs in vivo and effectively suppress tumors in mice.

The researchers also showed that MSNs accumulate almost exclusively in tumors after administration and that the nanoparticles are excreted from the body after they have delivered their .

The study was conducted jointly in the laboratories of Fuyu Tamanoi, a UCLA professor of microbiology, immunology and and director of the signal transduction and therapeutics program at UCLA's Jonsson Comprehensive Cancer Center, and Jeffrey Zink, a UCLA professor of chemistry and biochemistry.

In the study, researchers found that MSNs circulate in the bloodstream for extended periods of time and accumulate predominantly in tumors. The tumor accumulation could be further improved by attaching a targeting moiety to MSNs, the researchers said.

The treatment of mice with camptothecin-loaded MSNs led to shrinkage and regression of xenograft tumors. By the end of the treatment, the mice were essentially tumor free, and acute and long-term toxicity of MSNs to the mice was negligible. Mice with breast cancer were used in this study, but the researchers have recently obtained similar results using mice with human pancreatic cancer.

"Our present study shows, for the first time, that MSNs are effective for anticancer drug delivery and that the capacity for tumor suppression is significant," Tamanoi said.

"Two properties of these nanoparticles are important," Lu said. "First, their ability to accumulate in tumors is excellent. They appear to evade the surveillance mechanism that normally removes materials foreign to the body. Second, most of the nanoparticles that were injected into the mice were excreted out through urine and feces within four days. The latter results are quite interesting and might explain the low toxicity observed in the biocompatabilty experiments we conducted."

Researchers at the Nano Machine Center for Targeted Delivery and On-Demand Release are modifying MSNs — which are easily modifiable — so that the nanoparticles can be equipped with nanomachines. For example, nanovalves are being attached at the opening of the pores to control the release of anticancer drugs. In addition, the interior of the pores is being modified so that the light-induced release of anticancer drugs can be achieved.

"We can modify both the particles themselves and also the attachments on the particles in a wide variety of ways, which makes this material particularly attractive for engineering drug-delivery vehicles," Zink said.   

The team is now planning future research that involves testing MSNs in a variety of animal-model systems and carrying out extensive studies on the safety of MSNs.

"Comprehensive investigation with practical dosages which are adequate and suitable for in vivo delivery of is needed before MSNs can reach clinics as a system," Tamanoi said.

The research received support from National Institutes of Health and the National Science Foundation. In addition, NanoPacific Holdings Inc. provided critical support for the animal experiments.

Explore further: Smart Nanocarriers to Combat Tumors

Related Stories

Smart Nanocarriers to Combat Tumors

April 26, 2005

A ‘smart’ nanocarrier technology developed by a team of researchers at the Institute of Bioengineering and Nanotechnology (IBN) is set to vastly improve the way cancer patients are treated.

Nanoparticles carry cancer-killing drugs into tumor cells

June 15, 2005

Increased efficacy, lower drug toxicity in mice University of Michigan scientists have created the nanotechnology equivalent of a Trojan horse to smuggle a powerful chemotherapeutic drug inside tumor cells – increasing ...

Nanoparticles Overcome Anticancer Drug Resistance

June 12, 2006

Too often, chemotherapy fails to cure cancer because some tumor cells develop resistance to multiple anticancer drugs. In most cases, resistance develops when cancer cells begin expressing a protein, known as p-glycoprotein, ...

Tiny delivery system with a big impact on cancer cells

December 15, 2008

Researchers in Pennsylvania are reporting for the first time that nanoparticles 1/5,000 the diameter of a human hair encapsulating an experimental anticancer agent, kill human melanoma and drug-resistant breast cancer cells ...

Nanoparticles Cooperate to Detect and Treat Tumors

March 26, 2010

(PhysOrg.com) -- If one nanoparticle is good, two may be better, especially when they are designed to cooperate with each other to diagnose and treat cancer. That finding comes from work led by Michael Sailor, Ph.D., a member ...

Recommended for you

For 2-D boron, it's all about that base

September 2, 2015

Rice University scientists have theoretically determined that the properties of atom-thick sheets of boron depend on where those atoms land.

Electrical circuit made of gel can repair itself

August 25, 2015

(Phys.org)—Scientists have fabricated a flexible electrical circuit that, when cut into two pieces, can repair itself and fully restore its original conductivity. The circuit is made of a new gel that possesses a combination ...

An engineered surface unsticks sticky water droplets

August 31, 2015

The leaves of the lotus flower, and other natural surfaces that repel water and dirt, have been the model for many types of engineered liquid-repelling surfaces. As slippery as these surfaces are, however, tiny water droplets ...

Scientists grow high-quality graphene from tea tree extract

August 21, 2015

(Phys.org)—Graphene has been grown from materials as diverse as plastic, cockroaches, Girl Scout cookies, and dog feces, and can theoretically be grown from any carbon source. However, scientists are still looking for a ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

joefarah
5 / 5 (2) Jul 09, 2010
"Comprehensive investigation with practical dosages which are adequate and suitable for in vivo delivery of anticancer drugs is needed before MSNs can reach clinics as a drug-delivery system"

I'm sure there are some "terminally ill" cancer patients that would benefit from trials today. Let's assume there are long term side-effects - do you think these are worse than death? Short term side effects... if I'm terminally ill, I will certainly take my chances. Let's move this technology forward to human trials because if there is significant delay, you'd better expect some law suits.
Shaffer
5 / 5 (1) Jul 09, 2010
"Comprehensive investigation with practical dosages which are adequate and suitable for in vivo delivery of anticancer drugs is needed before MSNs can reach clinics as a drug-delivery system"

I'm sure there are some "terminally ill" cancer patients that would benefit from trials today. Let's assume there are long term side-effects - do you think these are worse than death? Short term side effects... if I'm terminally ill, I will certainly take my chances. Let's move this technology forward to human trials because if there is significant delay, you'd better expect some law suits.


I couldn't agree more!

My father was just diagnosed with stage IV colorectal cancer with liver metasticies...he would sign whatever waiver he had to for a better chance of beating it.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.