Tomography Imaging of Mammary Cancer Tumors in a Mouse
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Implanting oxygen-consuming batteries into mice with cancer caused their tumors to shrink or disappear within two weeks when used with an experimental class of cancer drugs.
As most tumors grow, they consume oxygen from the noncancerous tissue surrounding them so that the tumor cells become oxygen-starved, or hypoxic. A class of drugs, called hypoxia-active prodrugs (HAPs), seek to exploit this feature by killing only cells showing hypoxia, so that healthy cells are less affected, reducing the side effects of treatment. But no HAPs are approved for clinical use due to limited evidence of their effectiveness.
Now, fan zhang at Fudan University in Shanghai, China, and colleagues have developed a self-charging, implantable battery that runs off salt water injected into its surroundings, allowing the battery to generate very low-voltage electricity and consume oxygen . By creating a hypoxic environment, the battery should optimize the action of the HAP.
“The battery can cover tumors and consume oxygen continuously for more than 14 days, which is much longer than previous agents [that worked for] Usually no more than two days,” says Zhang.
Zhang and his team placed the batteries next to 25 mice with breast cancer. Five received functional battery and HAP treatment. The remaining mice were arranged into groups where they received either no treatment, only HAP drugs, an implanted battery that did not work or only a working battery that could last up to 500 hours in mouse tissue.
After fourteen days, tumors had shrunk by an average of 90 percent in the five mice that received the working battery and HAP treatment, and in four of these mice they had disappeared completely. The tumors remained the same size or grew in other mice groups.
Zhang says while the battery poses no safety concerns when used in rats, the safety bar for people is high, so further research is needed to ensure it is compatible with human tissue.
randall johnson At the University of Cambridge say that inducing hypoxia in tumors can have negative aspects, such as an increased tendency for cancer to spread elsewhere in the body. While this didn’t happen in rats, the costs and benefits of using the battery in people will need to be assessed before any human treatment, he says.
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