Toxic stem cells to fight tumors

A Harvard team has developed special stem cells that secrete toxins that kill cancer cells, and cause no harm to healthy ones.

“Now, we have toxin-resistant stem cells that can make and release cancer-killing drugs,” Khalid Shah, a co-author of the study and the director of the Molecular Neurotherapy and Imaging Lab at Massachusetts General Hospital and Harvard Medical School, said in an official statement.

According to Shah, experiments in mice have proven very successful.

During the tests, the main part of the brain tumor was surgically removed, followed by the application of stem cells that were placed at the site of the tumor embedded in a biodegradable gel to kill the remaining cancerous cells.

Once within the cancer cell, the toxin disrupts its ability to synthesize proteins, killing it in a matter of days.

“After doing all of the molecular analysis and imaging to track the inhibition of protein synthesis within brain tumors, we do see the toxins kill the cancer cells,” he declared.

Shah said that the toxins that kill cancer have been used to treat a few types of blood cancers. However, these toxins were not effective dealing with solid tumors because these cancers are not as accessible and the toxins in the stem cells don’t have enough time to kill the cancer, since they only have a short half-life.

However, the new modified stem cells developed by Shah’s team change this limitation. “Now, we have toxin-resistant stem cells that can make and release cancer-killing drugs,” he said.

The study, published in the journal Stem Cells, possibly represents a breakthrough in cancer research, since it kills cancer cells while keeping remaining, healthy cells intact.

Scientists have applied for approval from the FDA to start the clinical trials of the method.

Experts praised the study as “the future” of cancer research.

“This is a clever study, which signals the beginning of the next wave of therapies. It shows you can attack solid tumors by putting minipharmacies inside the patient which deliver the toxic payload direct to the tumor,” Chris Mason, a professor of regenerative medicine at University College London, who was not participating in the study, told the BBC.