Nari Jang, a doctoral student presenting work at the meeting, said early diagnosis of cancer is crucial for effective treatment and survival. Therefore, cancer screening methods must be quick, easy, economical and non-invasive.
Currently, doctors diagnose lung cancer with imaging tests or biopsies, but these methods often cannot detect tumors in their earliest stages.
Although dogs can be trained to sniff out human cancers, they are impractical to keep in a laboratory. So Dr. Jang and Shin Sik Choi, the project’s principal investigator, decided to use worms called nematodes, which are very small (~1 mm long), easy to grow in the lab. and have a special sense of smell, to develop a non-invasive cancer diagnostic test.
“Lung cancer cells produce a different set of odor molecules than normal cells“, Choi, currently studying at Myongji University, South Korea, said.
“It’s well known that the soil-dwelling roundworm, C. elegans, is attracted or repelled by certain odors, so we came up with the idea that roundworms could be used to detect lung cancer.. “
Other researchers placed roundworms in a petri dish and added drops of human urine, observing that the worms preferentially crawled toward urine samples from cancer patients. Jang and Choi wanted to create an accurate, easy-to-measure test.
So the team created a chip from polydimethylsiloxane elastomer that has a well at each end connected by channels to a central chamber. The researchers placed the chip on a plate of agar. At one end of the chip, they added a drop of culture medium from lung cancer cells, and at the other end, they added medium from normal lung fibroblasts.
They placed the worms in the central chamber, and after an hour, they observed more worms crawling on the lung cancer vehicle than on the conventional vehicle. In contrast, worms with a mutated odorant gene called odr-3 did not exhibit this preferential behavior.
Based on these tests, the researchers estimate that the device is about 70 percent effective at detecting cancer cells in diluted cell cultures. They hope to increase both the accuracy and sensitivity of this method by using worms that have previously been exposed to the cancer cell environment and thus have a “memory“of cancer-specific odor molecules.
After the team has optimized the chip to detect cultured lung cancer cells, they plan to move on to testing human urine, saliva or even exhaled breath.
“We will work with medical doctors to find out if our method can detect lung cancer in patients at an early stage.“They also plan to test the device on many forms of cancer,” Choi said.
In other studies using worm-on-a-chip, the researchers identified specific odor molecules that attract C. elegans to lung cancer cells, including an organic compound. a volatile organic compound called 2-ethyl-1-hexanol, which has a floral scent. “We don’t know why C.elegans are attracted to lung cancer tissues or 2-ethyl-1-hexanol, but we guess that the smell is similar to that from their favorite food.“, said Jang.
Source: Medindia
