By Staff Reports
(DGIwire) – In 2013, the journal Science called cancer immunotherapy the year’s most groundbreaking advancement. Several years later, scientists continue to be excited by this field of research, which aims to enhance the body’s immune system to kill tumor cells.
A notable finding was announced in the pages of Cell Reports in May 2016. Researchers at Karolinska Institutet (KI) in Sweden were able to generate antibodies that “reprogram” a type of cell, called a macrophage, that is found in tumors. Doing this, they reported, makes the immune system better able to recognize and kill tumor cells. According to KI, this finding could lead to a potentially important diagnostic tool for breast cancer and malignant melanoma.
The normal function of macrophages is to combat infection. Some macrophages, however, affect their environment in the tumor in a way that makes it easier for cancer cells to survive and spread. Specifically, these macrophages can prevent immune cells from recognizing and killing cancer cells, reports KI. The researchers managed to alter the structure of these macrophages in a way that stopped the tumors from growing and spreading in mice. The researchers expressed hope that their new therapy would one day be used in combination with others to make it more effective.
Other researchers are aiming to combine immunotherapy with separate cutting-edge approaches to beef up the attack on cancer cells. Among the most exciting of these “combo” therapies are those that aim to combine immunotherapy agents with viruses that have shown the ability to target and attack tumor cells on their own.
The use of viruses—with significant potential in treating various forms of cancer when combined with immunotherapy or standard chemotherapy—is called virotherapy or oncolytic virus therapy. It involves the conversion of viruses into cancer-fighting agents by reprogramming them to attack cancerous cells, while healthy cells remain relatively undamaged. Specifically, viruses can be harnessed to infect, multiply within and subsequently destroy cancer cells; the drug targets the tumor and protects normal tissue.
“Oncolytic virus therapy has repeatedly indicated its potential in a wide range of clinical studies,” says Brad Thompson, Ph.D., president and CEO of Oncolytics Biotech Inc. “This includes fruitful advances made with one particular type of oncolytic virus, known as the reovirus.”
The reovirus is a non-enveloped virus with a double-stranded, segmented RNA genome. It preferentially replicates in cancer cells that have an “activated Ras pathway,” which is caused by mutations in certain genes. The reovirus leaves normal cells unharmed. This makes it intrinsically tumor-selective without the need for any genetic manipulation. With no known associated disease, the reovirus replicates in the cytoplasm and therefore does not integrate into the cell’s DNA. It is found commonly in nature and has been isolated from untreated sewage, river and stagnant waters. Exposure to the reovirus is common in humans, with half of all children by the age of 12 having been exposed and up to 100 percent testing positive by adulthood.
Oncolytics’ lead product, REOLYSIN®, is a proprietary formulation of the human reovirus. It has been utilized in nearly 30 clinical studies in a range of cancers, including ovarian, pancreatic, prostate, colorectal, non-small cell lung and breast cancers.
“The exciting future of cancer treatment could very well lie in cutting-edge applications of new therapies involving oncolytic viruses, and we are proud to be working in such a fast-evolving field,” adds Thompson.