We Could Use Ultrasound to Command Bacteria to Nuke Tumors
Ultrasound is probably best known as a way to observe the body’s insides, like to check up on a growing fetus or detect problems in someone’s heart. But it’s also used to fight cancer by sending high frequency sound waves to fry these abnormal cells. Focused ultrasound is used mostly against localized cancers like prostate. This treatment is about to get a big boost from an unlikely ally: bacteria.
In a new study reported in the journal Nature Communications on March 24, researchers at Caltech genetically modified E. coli bacteria to kill cancer after being activated by ultrasound-induced heat—laying any harm to surrounding healthy cells. These bacteria not only prevented tumors in mice from growing larger, they also managed to cut down a tumor’s size outright. The findings may help clinicians develop a more targeted search-and-destroy method for combating cancer, and might also be adapted later on into helping fight off other infections localized to a specific part of the body.
Using bacteria to wage a battle against cancer may sound out of left field, but scientists have known about bacteria’s strange attraction to cancer since the 19th century, Mikhail Shapiro, a biochemical engineer at Caltech who led the new study, told The Daily Beast. “More than 100 years ago, [American surgeon] William Coley noticed that if you have some bacteria present in a tumor, you can get beneficial anti-tumor effects,” he said. “More recently, people have seen that you can inject certain bacteria into the bloodstream and they will get cleared almost everywhere by the immune system” except where a tumor is, since cancer works hard to weaken the immune system to avoid detection.
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