In a medical breakthrough scientists have found a protein called perforin that kills rogue cells in the human body especially the ones causing cancer. The team comprising of experts from Melbourne and London found that perforin punches holes and kills these cells. The research appeared in the acclaimed journal Nature.
Monash University professor James Whisstock explained, “Perforin is our body's weapon of cleansing and death… It breaks into cells that have been hijacked by viruses or turned into cancer cells and allows toxic enzymes in, to destroy the cell from within… Without it our immune system can't destroy these cells. Now we know how it works, we can start to fine tune it to fight cancer, malaria and diabetes.”
Earliest observations that the human immune system could punch holes in target cells was seen by Nobel laureate Jules Bordet over 110 years ago. It is now that the team from Monash University and the Peter MacCallum Cancer Centre in Melbourne, and Birkbeck College in London came together in this decade long study to look at the exact molecular mechanism. The team used Australian Synchrotron and the powerful electron microscopes at Birkbeck to find the molecular structure. They found how perforin forms a hole in the cell membranes of the target cells. They also found that the perforins worked similar to toxic bacteria like anthrax, listeria and streptococcus.
According to head of cancer immunology at the Peter MacCallum Cancer Centre, Professor Joe Trapani, “The molecular structure has survived for close to two billion years, we think.” They also noted that it is this perforin that causes the body to turn against itself like in autoimmune disease conditions, such as early onset diabetes, or in tissue rejection following bone marrow transplantation.
“The first major step in understanding perforin came from the discovery that it is related to a family of bacterial toxins, including pneumolysin, which we had previously studied,” said researcher Helen Saibil of Birkbeck College London, UK. “We went on to obtain an electron microscopy map of perforin pores, and we could see some similarities to pneumolysin pores but we couldn't interpret the structure in detail.”
“This is a wonderful extension of the breakthrough work of 2007,” said Hagan Bayley of the University of Oxford, UK, referring to the discovery of the similarity between perforin and bacterial pores. “The weapons used by our immune cells and by pathogenic bacteria have a common origin, but now it seems they swing their swords in different ways,” he added.
A $1 million grant from the Wellcome Trust will aid in further research on using these proteins against cancer and other diseases.