Researchers reveal how a process called caspase-independent cell death (CICD) frequently led to the complete eradication of colorectal cancer cells, which is not often the case with current cancertreatments.
Study co-author Dr. Stephen Tait, of the Cancer Research UK Beatson Institute at the University of Glasgow in the United Kingdom, and colleagues recently reported their findings in the journal Nature Cell Biology.
Cancer remains one of the biggest health burdens of our time. Last year, more than 1.6 million new cases were diagnosed in the United States alone, and almost 600,000 people died from the disease.
Dr. Tait and team explain that the majority of current cancer therapies work by inducing apoptosis. Apoptosis is a form of programmed cell death, or cell suicide, that helps to rid the body of abnormal or unnecessary cells by activating proteins called caspases. In cancer cells, however, apoptosis is often inactive.
Reactivating apoptosis in cancer cells – through chemotherapy or immunotherapy, for example – is one way of killing them. But this is not always effective.
Research has shown that cancer cells are sometimes able to evade treatment-induced apoptosis, and some studies have suggested that apoptosis may even promote cancer growth.
CICD, however, takes cancer killing one step further, and Dr. Tait and team suggest that it may be a more effective way to treat cancer than current therapies.
CICD prompts immune system attack
In their study, the researchers explain that CICD kills cancer cells through a process called mitochondrial outer membrane permeabilization (MOMP), but it does so without releasing caspases, which are the proteins that are normally released through apoptosis.
“[…] cells typically die following MOMP even in the absence of caspase activity […],” the team explains. “This defines MOMP as a point of no return that commits a cell to die.”
Importantly, when cancer cells die as a result of CICD, they send signals to the immune system, prompting it to attack and destroy the cancer cells that managed to escape CICD.
When Dr. Tait and team tested this technique on colorectal tumors grown in the laboratory, they found that it managed to kill almost all cancer cells.
While further studies are needed to confirm the safety and efficacy of CICD, the researchers believe that it could lead to better treatments for a number of cancers.
“In essence, this mechanism has the potential to dramatically improve the effectiveness of anti-cancer therapy and reduce unwanted toxicity.”
Dr. Stephen Tait
“Taking into consideration our findings, we propose that engaging CICD as a means of anti-cancer therapy warrants further investigation,” he adds.