Oral Cancer News

Source: Reuters Health Information via Medscape Today

LONDON (Reuters) Aug 12 – Treating tumors with salmonella bacteria can induce an immune response that kills cancer cells, scientists have found — a discovery that may help them create tumor-killing immune cells to inject into patients.

Researchers from Italy and the United States who worked with mouse and human cancer cells said their work might help in developing new therapeutic vaccines.

“We did experiments first in mice and then in cancer cells and immune cells from human patients, and found that the salmonella was doing exactly the same job,” Dr. Maria Rescigno of European Institute of Oncology in Milan, who worked on the study, said in a telephone interview. “Now we are ready to go into (testing on) humans, but we are waiting for authorization.”

The scientists said they thought the salmonella bacteria helped to flag up cancer cells to the body’s immune system, which was then able to find and kill them.

In the very earliest stages of cancer, patrolling immune cells often recognize cancer cells as abnormal and destroy them, they explained in their study, which was published online in Science Translational Medicine on Wednesday.

This process relies on connexin 43, a protein that forms tiny communication channels between different types of cells. Tumor peptides escape through these channels, enter immune cells, and act as “red flags,” triggering a specific immune response against the disease.

But as cancer cells grow and proliferate, they can become invisible to immune cells because not enough connexin 43 is made to keep the “red flag” process going.

In this study, the scientists looked mainly at melanoma cells,

Dr. Rescigno and colleagues found that injecting salmonella into melanoma cells increased the amount of connexin 43. As a result, new communication channels formed, and immune cells were activated and went on to kill the tumor cells.

The technique also protected mice from cancer spreading to other parts of the body, Dr. Rescigno said, suggesting a potential “vaccination-style” preventative strategy.

Immunotherapy is a relatively new approach. In April, the U.S. Food and Drug Administration regulators approved Dendreon Corp’s Provenge, a therapeutic vaccine designed to stimulate the immune system to attack prostate cancer, as the first vaccine to treat tumors.

An experimental immunotherapy drug called ipilimumab being developed by Bristol-Myers Squibb showed promise in fighting melanoma in trial data released in June.

Dr. Rescigno said the team used melanoma cells in the study because this disease is one of the deadliest forms of cancer, same technique could also be tested in other types of cancer.