Novel ‘nanobombs’ could deliver miRNA to attack cancer stem cells

Nanoparticles known as ‘nanobombs’ that swell and burst upon exposure to near-infrared laser light have been developed in at The Ohio State University Comprehensive Cancer Center (OH, USA).

These nanobombs could be harassed to kill or slow the growth of tumor cells by efficiently packaging and delivering miRNA agents to the tumor site, where they can alter malignant gene expression. This strategy could circumvent the issue of degradation of free miRNA by the body – a notorious problem with this type of drug.

The study, published recently in the journal Advanced Materials, has also provided a solution to a second major problem: the inability of nanoparticles and miRNA to escape encapsulation by endosomes and reach their target in the cancer cell.

“We believe we’ve overcome this challenge by developing nanoparticles that include ammonium bicarbonate, a small molecule that vaporizes when exposing the nanoparticles to near-infrared laser light, causing the nanoparticle and endosome to burst, releasing the therapeutic RNA,” commented Xiaoming (Shawn) He, principal investigator of The Ohio State University Comprehensive Cancer Center.

Near-infrared laser light can penetrate tissue to a depth of one centimeter. However, minimally invasive surgery would be required to deliver light to deeper tumors.

In their investigations, the team utilized nanoparticles equipped to target cancer stem-like cells, which are thought to play a significant role in tumor recurrence. miR-34a was chosen as the therapeutic agent due its ability to reduce levels of a protein crucial for cell survival and therapeutic resistance.

While the nanobomb delivery method was tested in human prostate cancer cells and human prostate tumors in animal models, it could prove promising for human use in clinical trials.

Sources: Wang H, Agarwal P, Zhao S, Yu J, Lu X, He X. A near-infrared laser-activated “Nanobomb” for breaking the barriers to MicroRNA delivery. Advanced Materials. DOI: 10.1002/adma.201504263 (2015); The Ohio State University Comprehensive Cancer Center press release