A team led by researchers at the Karolinska Institute in Sweden and Nanyang Technological University in Singapore recently reported that an already existing chemotherapy drug for the treatment of leukemia can reduce the growth of colorectal cancer. The study was published in the prestigious journal Science Translational Medicine and is entitled “An EphB-Abl signaling pathway is associated with intestinal tumor initiation and growth.”
Colon cancer is a common malignancy that usually develops from abnormal growths (polyps) in the inner walls of the large intestine. Normally these growths are primarily benign tumors that, when not treated, become aggressive and may metastasize (spread) to other parts of the body. Screening and polyp removal can prevent the disease. Colon cancer is estimated to be the third leading cause of cancer death in the United States and is the most common cancer in Singapore.
In the study, the research team reports the discovery that Imatinib, a drug used in leukemia treatment, can reduce by half the tumor growth in the intestine of mice with colon cancer, increasing their survival rate.
“In mice which mimicked human colon cancer, Imatinib was shown to prolong their life span,” said one of the study’s lead authors Dr. Parag Kundu in a news release. “The drug was also effective in increasing the survival of mice which had late-stage tumors and rectal bleeding.” Furthermore, Imatinib was also found to be able to reduce tumor cell proliferation and growth on colon cancer tissues taken from human patients.
Researchers found that Imatinib acts by blocking a signaling pathway that is linked to a group of cell receptors known as ephrin receptors B (EphB). EphB receptors are known to act as tumor promoters for adenoma (a non-cancerous tumor that can be a precursor of colon cancer), although they block tumor progression to invasive carcinoma. Imatinib treatment was found to inhibit the tumor-promoting effects of EphB signaling, suggesting that EphB plays a role in the initiation of intestinal tumors. On the other hand, Imatinib treatment did not attenuate the invasive tumor suppression effects of EphB signaling.
“Our findings provide experimental evidence that Imatinib treatment did not interfere with the tumor suppressor function of EphB receptors,” said one of the study’s senior authors Dr. Jonas Frisén. This observation is important because it suggests that Imatinib treatment does not affect EphB receptors’ role in preventing the spread of cancerous cells to the surrounding tissue.
The research team concluded that Imatinib can represent a new treatment strategy for colon cancer. “Our work has important clinical implications, since Imatinib is a potentially novel drug for the treatment of tumor formation and cancer progression in patients predisposed to develop colorectal cancer,” concluded one of the study’s senior authors Dr. Sven Pettersson.