Sri Lankan Hasini Jayatilaka and a team at Johns Hopkins discovered the biochemical mechanism that tells cancer tells to break off and spread throughout the body, a process called metastasis. Some 90 percent of cancer deaths are caused when cancer metastasizes. They also found that two existing, FDA-approved drugs can severely slow metastasis.
Hasini 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 it is a bona fide discovery that offers significant promise for cancer treatment. The study was published online May 26 in the journal Nature Communications. The team is set 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.”
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. The team then tested two drugs known to work on the Interleukin receptors to see if they would block or slow metastasis in mice. They found that using Tocilizumab, a rheumatoid arthritis treatment, and Reparixin, which is being evaluated for cancer treatment together would block the signals from the Interleukin proteins that told the cancer cells to break off and spread, slowing — though not completely stopping metastasis.