Existing parasite drug may fight prostate, colon cancer

New research has found evidence to suggest that nitazoxanide, a substance contained in antiparasitic drugs, could be effective in deterring the growth of prostate and colon cancer cells.

According to the American Cancer Society (ACS), prostate cancer is the second most common cancer type among men in the United States. Prostate cancer makes up 9.6 percent of all new cancer cases in the U.S., while colorectal cancer accounts for 8 percent of all newly diagnosed cases in the country.

In the case of both prostate and colon cancer, the dysregulation of a cellular signaling pathway called Wnt (wingless)/Beta-catenin signaling can lead to the growth and proliferation of cancer cells.

Researchers from the University of Bergen in Norway have recently been looking to explore the potential of already-available drugs to interact with and inhibit this cancer cell proliferation.

Prof. Karl-Henning Kalland and his team have now isolated a substance called nitazoxanide (NTZ), contained in existing antiparasitic drugs, as potentially effective against cancer cell growth.

"We discovered that this specific substance is blocking the signaling pathway in the cancer cells, and [making] them stop growing. It is not often that researchers discover a substance that targets specific molecules as precisely as this one."

Prof. Karl-Henning Kalland

The study's findings were recently published in the journal Nature Chemical Biology.

Available drug halts growth of cancer cells

"We assessed the effects of NTZ on Wnt-activated human colon cancer cells," the team reports. They also note that colon cancer and prostate cancer cells exhibit high levels of Wnt (wingless)-activated Beta-catenin. This is a protein that helps to regulate gene transcription and cellular interaction.

When Beta-catenin signaling is faulty, cancerous cells can develop. It can also render cancer cells more resilient.

The team found that NTZ could act on the activated Beta-catenin pathway to effectively block it and stop the growth of cancer cells.

"We are the first researchers," claims Prof. Kalland, "who have mapped the complex molecular mechanisms involved in this process."

He also explains why experimenting with drugs that are already known and approved by the Food and Drug Administration (FDA) is so important. FDA-regulated drugs have already been tested in clinical trials and used in treatments, so scientists and healthcare professionals are familiar with their possible effects on the body.

NTZ's use in immunotherapy to be tested

"The advantage of testing already-approved drugs," says Prof. Kalland, "is that we know they work in the human body and have no serious side effects, which means that a future treatment may happen quicker."

Still, further research is needed in order to ascertain NTZ's full potential in the treatment of prostate and colon cancer.

The effect of this substance on the activated Beta-catenin signaling pathway also impacts the immune response of the body, the researchers explain. In their experiments, they noted that NTZ seems to stimulate the immune system into action.

"At the moment," Prof. Kalland adds, "we are working on how to strengthen our ongoing immune therapy against prostate cancer by using the mechanisms we discovered of the NTZ."

Following the results obtained in this study, he and his team are conducting the first phase of a clinical trial targeting the use of immunotherapy in the treatment of prostate cancer.