AACR: Gold nanorods aim cancer-killing lasers at the bladder

In a study presented at the American Association for Cancer Research in San Diego this week, researchers from the University of Colorado described a cancer-killing method that uses gold nanorods to target tumor cells in the bladder.

Bladder cancer cells have an abundance of the protein epidermal growth factor receptor (EGFR), the UC Cancer Center wrote in a blog post, and the researchers exploited this fact with gold nanoparticles designed to find and attach specifically to these proteins. Their shape--long and thin as opposed to spherical--allows them to stick more readily to the EGFRs.

Once the nanorods are attached, the scientists used a specially tuned laser to heat the nanorods from the outside. This heat is enough to kill the cancer cells with the nanorods on their surface but not enough to harm surrounding healthy tissue.

"These early-stage bladder cancers aren't necessarily addicted to EGFR--they don't need it to survive or grow like many EGFR-dependent cancers and so using a drug to cut off this supply of EGFR doesn't do much good," said clinical investigations medical director Thomas Flaig in a statement. "However, the overexpression of EGFR marks these cells. Our approach depends only on recognizing and exploiting this marker."

In a mouse study, mice given the treatment showed no disease progression and 13 out of 16 mice had disease reduction, according to the blog post. Half of the mice treated only with the laser showed disease progression, and only two demonstrated a reduction in cancer cells.

"It's not as far from human application as it might seem," Flaig said. "We already treat bladder cancer patients with liquid-based drugs introduced into the bladder, and then patients are scoped regularly. You can see the pathway into clinical use. Instead of or in addition to drugs commonly in use, we could introduce engineered nanoparticles, and then the scope could easily transmit laser."

- here's the UCCC blog post
- and here's the AACR abstract