VOA常速英语:Tiny 'Nanobees' Fight Cancer

The challenge posed by many potentially effective anti-cancer drugs is how to use these deadly compounds to fight disease without harming the rest of the body. Dr. Sam Wickline may have found one solution. He develops tiny nanoparticles that carry medicine to the spot where it's needed.

"In this case," says Wickline, "we've taken a fairly toxic material which is a component of regular old bee venom - it's called melittin - and we've put that on our carrier and, lo and behold, it seems to get to the right place, do its job to treat cancers of several types, and then not cause trouble elsewhere."

A swarm of "nanobees" stings the tumor

Wickline and his colleagues at Washington University in Saint Louis tested their creations, which they affectionately call nanobees, on breast cancer tumors, melanoma tumors, and precancerous lesions in mice. "They were extremely effective," Wickline notes, "in all of those types of tumors given the...modest dosages that we used."

In particular, he adds, "they basically prevented [melanoma tumors] from growing, and in precancerous lesions in the skin - even before a tumor would have developed - they prevented that, at least in the short term, from turning into a cancer."

Wickline says the nanobees are able to target the disease thanks, in part, to the unusual leakiness of the blood vessels that surround tumors. "Now, the ones that get to the tumor can either get trapped in these leaky vessels or, we've put a homing system on them so that they know where the tumor is."

Wickline explains that the homing system works because "the blood vessels around the tumor that supply it with oxygen and nutrients, express a kind of...code that's not found on most normal tissues in your body."

Moving toward tests on humans

Wickline hopes to have human clinical trials underway in about two years. He predicts the federal drug approval process will be more drawn out because of the number of components involved in this kind of treatment. "Because these are very complex structures, there may be more things to monitor when you do the safety testing," Wickline says. "So the different number of tests that you have to run… makes it more difficult, more expensive, and a longer time course."

Wickline's research on cancer fighting nanobees is published in the Journal of Clinical Investigation.