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<\/a>Credit: Chris Bickel\/Science Translational Medicine<\/figcaption><\/figure>\n
Vijee Venkatraman
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\n05\/27\/2015<\/p>\n
TOPICS
\nResearch Bacteria cancer Lemelson-MIT Prize MIT Sangeetha Bhatia
\nEating a spoonful of probiotic-fortified yogurt, followed by a quick urine test, may someday be enough to tell if cancer has spread to your liver.<\/p>\n
In a study published in this week\u2019s issue of Science Translational Medicine, researchers present a rapid, non-invasive way to detect liver cancer that\u2019s shown promise in tests in mice. Their approach: hijack the body\u2019s digestive system and use bacteria as messengers.<\/p>\n
Cancers commonly recur in the liver long after the cells have disappeared from other organs. Researchers are still exploring reasons why that\u2019s the case, but they do know that because the liver can regrow, patients have a high chance of recovery \u2014 if the cancer\u2019s caught quickly.<\/p>\n
\u201cNew data are showing that those patients have a higher survival rate, so there\u2019s a particular need for detecting early metastasis in the liver,\u201d said Sangeeta Bhatia, director of the Laboratory for Multiscale Regenerative Technologies at MIT, who worked on the study.<\/p>\n
The catch is that because liver tumors tend to be small and dispersed, they can be hard to detect using imaging techniques. A better way, Bhatia and team propose in their new study, is to use bacteria as tumor scouts \u2014 the microbes have long been known to thrive in these nutrient-rich zones \u2014 and engineer them to emit a signal once they reached the mass and multiply. That indicator then can be detected in the person\u2019s urine.<\/p>\n
This is where the probiotic yogurt comes in: It turns out the best way to get the bacteria into the liver is to eat them mixed into a parfait, say, and let the bugs make their way through the digestive system.<\/p>\n
In their study, the researchers picked a harmless strain of E. coli called Nissle 1917, which is marketed as a promoter of gastrointestinal health.<\/p>\n
\u201cThis is a safe and widely used probiotic,\u201d said Arthur Prindle, currently a post-doctoral student at UCSD, who along with MIT postdoc Tal Danino, is a lead author on the paper. \u201cIn fact, we were able to order it from Amazon and engineer it to express the genes we wanted.\u201d<\/p>\n
The researchers fed the bacteria-laced yogurt to the rodents. When the bacteria reached the liver, it was designed to release enzymes if it encountered a tumor. The rodents were then injected with a compound that interacted with the enzymes, releasing a molecule that was excreted in urine.<\/p>\n
This paper demonstrates the potential of engineered probiotic bacteria with synthetic circuits to enable diagnostics in the body, says Timothy Lu of the Research Laboratory of Electronics at MIT, a core member of the institute\u2019s Synthetic Biology Center. \u201cThe ability to sense disease states and trigger outputs that can show up in the urine opens up new possibilities for non-invasive disease monitoring with useful applications for clinical medicine.\u201d<\/p>\n
Extensive testing is needed before it reaches a clinic, but Bhatia is an experienced hand at commercializing lab discoveries. She won the $500,000 Lemelson-MIT Prize in 2014, previously worked on a method to detect colorectal cancer using nanoparticles, and is also the co-founder of two biotech companies Hepregen and Zymera.<\/p>\n
Bhatia said the group has already filed patents to allow commercial investment in this new technology. Currently, the MIT team is working on understanding the trafficking of probiotics from the gut to the liver and exploring therapeutic as well as diagnostic strains.<\/p>\n