Stealth Nanoparticles Home In On Bone Cancer Cells

Researchers have devised a nanoparticle delivery system that could target bone cancer cells with more precision than existing therapies in order to delay cancer progression and metastasis.

Scientists have been using nanotechnology to devise techniques that could slow down the progression of diseases, or eliminate them altogether. In principle, by using nanoparticles, nanodevices, nanorobots -- or any variation thereof -- researchers are able to deliver drugs with pinpoint accuracy to target cells or tissues without harming surrounding areas of the body. Research in this field can pave the way for efficient treatments for many diseases, including cancer.

In one of the latest cancer studies using nanotechnology, researchers working at the Dana-Farber Cancer Institute and Brigham and Women’s Hospital (BWH) have invented a technique using nanoparticles that target bone cancer cells. They chose to experiment on cells in the bone because of their role in the development and spread of most known cancers.

“Bone is a favorable microenvironment for the growth of cancer cells that migrate from tumors in distant organs of the body, such as breast, prostate and blood, during disease progression,” Archana Swami, PhD, BWH Laboratory of Nanomedicine and Biomaterials, and co-lead study author, said in a statement. “We engineered and tested a bone-targeted nanoparticle system to selectively target the bone microenvironment and release a therapeutic drug in a spatiotemporally controlled manner, leading to bone microenvironment remodeling and prevention of disease progression.” 

The researchers used stealth nanoparticles which were made of biodegradable polymers and coated with the therapeutic and biphosphonate agent called alendronate. The biphosphonate coating binds with the plentiful calcium stores in the bone, and allows the nanoparticle to deliver its payload of drugs to kill cancer cells selectively. Biphosphonate is also being used for treating metastatic cancers, so its utility in this nanotech experiment has been two-fold.

“There are limited treatment options for bone cancers,” Michaela Reagan, PhD, of Dana-Farber’s Center for Hematologic Oncology, and co-lead study author, said in the statement. “Our engineered targeted therapies manipulate the tumor cells in the bone and the surrounding microenvironment to effectively prevent cancer from spreading in bone with minimal off-target effects.”

As described in their study published in Proceedings of the National Academy of Sciences of the United States of America (PNAS), the researchers tested the nanoparticles on mice with multiple myeloma (MM), a type of cancer that affects white blood cells in the bone marrow. The results showed that there was a slowing down of the progression of the disease, and overall survival rates improved. When they used the anti-cancer drug bortezomib as a pretreatment regimen, it increased bone strength and volume. In the study, the researchers concluded that nanoparticle-based “anticancer therapies with bone-targeting specificity comprise a clinically relevant method of drug delivery that can inhibit tumor progression in MM.”

“These findings suggest that bone-targeted nanoparticle anti-cancer therapies offer a novel way to deliver a concentrated amount of drug in a controlled and target-specific manner to prevent tumor progression in multiple myeloma,” Omid Farokhzad, director of the BWH Laboratory of Nanomedicine and Biomaterials, and co-senior author of the study, said in the statement. “This approach may prove useful in treatment of incidence of bone metastasis, common in 60 to 80 percent of cancer patients and for treatment of early stages of multiple myeloma.”

Such novel treatments using nanotechnology could help stem the rising incidence of cancer in the Middle East. According to Nature Middle East, cancer cases in the region are estimated to double in the next decade, more than any other part of the world.