Conventional cancer treatments, such as chemotherapy and radiation can cause toxic side-effects. Now, researchers have discovered that a drug called thioridazine can successfully destroy cancer stem cells in humans without these effects.

Mick Bhatia, lead researcher of the study and scientific director of McMaster’s Stem Cell and Cancer Research Institute in the Michael G. DeGroote School of Medicine, said: “The unusual aspect of our finding is the way this human-ready drug actually kills cancer stem cells; by changing them into cells that are non-cancerous.”

Findings from the study could pave the way for the development of anticancer drugs in the treatment of various cancers. In addition to thioridazine, the team have identified another 12 drugs that also have good potential for the same response. The study is published in the journal CELL.

Cancer stem cells were first identified in certain types of leukemia by Canadian researchers over a decade ago. Since then they have been identified in ovarian, prostate, lung, brain, breast, blood, and gastrointestinal cancer.

The researchers developed an automated robotic system in order to identify different compounds of several drugs, including thioridazine.

Bhatia explained: “Now we can test thousands of compounds, eventually defining a candidate drug that has little effect on normal stem cells but kills the cells that start the tumor.”

The researchers next step is to test thioridazine in clinical trials in patients with acute myeloid leukemia whose cancer has relapsed following chemotherapy. Their goal is to determine whether the drug can put a patients cancer into remission and prevent it from returning by targeting the cancer stem cells.

In patients with leukemia and breast cancer, the team found that the drug works through the dopamine receptor on the surface of the cancer cells. According to Bhatia, this finding means that thioridazine may be a potential biomarker that would early detection and treatment of breast cancer as well as early signs of leukemia progression.

In addition, the researchers will also determine whether the drug is effective in other types of cancers and will investigate several other drugs identified along with thioridazine.

The team also plan to analyze thousands of other compounds with their screening system in partnership with collaborations that include academic groups and industry.

Bhatia said:

“The goal for all of the partners is the same – to find unique drugs to change the way we tackle and treat cancer.

This large scale research endeavor would have been impossible without the active support and vision of the Canadian and Ontario governments along with private donors.”

Written By Grace Rattue