[Note: This item comes from reader Randall Head. DLH]
Johns Hopkins researchers say they’ve unlocked key to cancer metastasis and how to slow it
By Carrie Wells
Jun 15 2017
Hasini Jayatilaka was a sophomore at the Johns Hopkins University working in a lab studying cancer cells when she noticed that when the cells become too densely packed, some would break off and start spreading.
She wasn’t sure what to make of it, until she attended an academic conference and heard a speaker talking about bacterial cells behaving the same way. Yet when she went through the academic literature to see if anyone had written about similar behavior in cancer cells, she found nothing.
Seven years later, the theory Jayatilaka developed early in college is now a bona fide discovery that offers significant promise for cancer treatment.
Jayatilaka and a team at Johns Hopkins discovered the biochemical mechanism that tells cancer cells to break off from the primary tumor and spread throughout the body, a process called metastasis. Some 90 percent of cancer deaths are caused when cancer metastasizes. The team also found that two existing, FDA-approved drugs can slow metastasis significantly.
“A female patient with breast cancer doesn’t succumb to the disease just because she has a mass on her breast; she succumbs to the disease because [when] it spreads either to the lungs, the liver, the brain, it becomes untreatable,” said Jayatilaka, who earned her doctorate in chemical and biomolecular engineering this spring in addition to her earlier undergraduate degree at Hopkins.
“There are really no therapeutics out there right now that directly target the spread of cancer. So what we came up with through our studies was this drug cocktail that could potentially inhibit the spread of cancer.”
The study was published online May 26 in the journal Nature Communications. The next step for the team is to test the effectiveness of the drugs in human subjects.
Typically, cancer research and treatment has focused on shrinking the primary tumor through chemotherapy or other methods. But, the team said, by attacking the deadly process of metastasis, more patients could survive.
“It’s not this primary tumor that’s going to kill you typically,” said Denis Wirtz, Johns Hopkins’ vice provost for research and director of its Physical Sciences-Oncology Center, who was a senior author on the paper.
Jayatilaka began by studying how cancer cells behave and communicate with each other, using a three-dimensional model that mimics human tissue rather than looking at them in a petri dish. Many researchers believe metastasis happens after the primary tumor reaches a certain size, but Jayatilaka found it was the tumor’s density that determined when it would metastasize.
“If you look at the human population, once we become too dense in an area, we move out to the suburbs or wherever, and we decide to set up shop there,” Jayatilaka said. “I think the cancer cells are doing the same thing.”
When the tumor reaches a certain density, the study found, it releases two proteins called Interleukin 6 and Interleukin 8, signaling to cancer cells that things had grown too crowded and it was time to break off and head into other parts of the body.
Previously, Wirtz said, the act of a tumor growing and the act of cancer cells spreading were thought to be very separate activities, because that’s how it appeared by studying cancer cells in a petri dish, rather than the 3-D model the Hopkins team used. Many researchers study only cancer cell growth or its spread, and don’t communicate with each other often, he said.
Once the cancer cells start to sense the presence of too many other cancer cells around them, they start secreting the Interleukin proteins, Wirtz said. If those proteins are added to a tumor that hasn’t yet metastasized, that process would begin, he said.