Ultrasound Can Selectively Eradicate Cancer Cells, Researchers Find

Not yet tried and tested on animals or humans, the promising study is still in its early stages.
Fabienne Lang

Ultrasound methods to eradicate tumors have been used for some time now. However,  these target and destroy both cancer cells and healthy cells. 

Now, a team of researchers from the California Institute of Technology (Caltech) and the City of Hope Beckman Research Institute has come up with a new ultrasound method, which targets only the cancer cells.

Their findings were published in the journal Applied Science Letters on January 7th. 


What is ultrasound therapy?

Ultrasound waves are sound waves that have too high a high frequency for humans to hear.

Previous methods of using ultrasound to kill cancer cells and healthy cells alike emit high-intensity bursts that heat up the tissue. This newly proposed method uses low-intensity pulsed ultrasound (LIPUS) and is more selective in choosing its targets. 

Ultrasound Can Selectively Eradicate Cancer Cells, Researchers Find
Left to right: Caltech principal investigators, Mory Gharib, Michael Ortiz, Mikail Shapiro, Source: Caltech

LIPUS exploits the unique physical and structural properties of tumor cells, providing a more targeted, selective, and safer option.

Trialling their method in petri dishes — the only place the team has so far conducted their research — the researchers were able to break apart a number of cancer cells without harming any healthy ones. 

Ultrasound Can Selectively Eradicate Cancer Cells, Researchers Find
Targeted pulsated ultrasound, Source: David Mittelstein/Caltech

"This project shows that ultrasound can be used to target cancer cells based on their mechanical properties," said David Mittelstein, lead author on the paper. "This is an exciting proof of concept for a new kind of cancer therapy that doesn't require the cancer to have unique molecular markers or to be located separately from healthy cells to be targeted."

Ultrasound Can Selectively Eradicate Cancer Cells, Researchers Find
Lead author of the study, David Mittelstein working on the project, Source: Caltech

The process goes by the name of oncotripsy — onco from the Greek "oncos" for tumor, and "tripsy" for breaking — which was given by Caltech's Michael Ortiz, Frank and Ora Lee Marble Professor of Aeronautics and Mechanical Engineering. 

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Oncotripsy is based on the idea that cells are vulnerable to ultrasound at specific frequencies — much like when an opera singer is able to shatter glass into a million pieces just from reaching a certain note. 

Ultrasound Can Selectively Eradicate Cancer Cells, Researchers Find
Left to right: City of Hope researchers Jian Ye and Peter P. Lee, Source: Eliza Barragan Ph.D/City of Hope

"Just by tuning the frequency of stimulation, we saw a dramatic difference in how cancer and healthy cells responded," Mittelstein said. "There are many questions left to investigate about the precise mechanism, but our findings are very encouraging."

The researchers hope that oncotripsy will get to a developed stage so as to be used alongside other cancer treatments such as chemotherapy, radiation, immunotherapy, and surgery.