GM cold virus kills cancer cells

17 Oct 2007

Researchers at the University of Birmingham have developed a method of using a genetically modified cold virus to target and kill tumour cells. Rather than delivering a drug, the virus acts as a method of delivering proteins that cause cancer cells to die.

The technique targets a molecule called CD40, which normally plays a key role in activating the immune system. Previous studies have shown that this molecule is present in many common tumours including breast, liver and skin cancers.

The genetically modified virus contains a protein CD40L that will bind to the CD40 on the surface of cancer cells. This binding process results in the death of the cancer cell. Using a modified form of the cold virus to deliver the genetic material also seems to have a dual effect, both in killing cancer cells and in stimulating a natural immune response to tumours.

The body does not normally produce an immune response to cancer cells, although scientists believe that rare cases where tumours disappear without treatment may be the result of an immune reaction.

Speaking at the recent National Cancer Research Institute (NCRI) Conference in Birmingham, Dr Daniel Palmer explained: “This approach has a number of possible advantages over conventional therapies. Firstly, focusing on CD40, which is expressed on cancer cells allows any therapy to be targeted at tumours.

Secondly it seems that targeting CD40 has a double benefit by both killing cells and activating the body’s immune system. Clearly it would be very beneficial if we can activate the body’s own immune system against the tumour. This would help reduce the toxic side effects associated with chemotherapy and possible tackle microscopic secondary tumours.”

Recently the research team enhanced the system by developing a modified version of the CD40L protein, which does not break up in contact with the cell wall. This enhances its toxicity to cancer cells.

The team are now looking at developing clinical trials for the technique possibly looking at its effect in liver and skin cancers.

Professor Lawrence Young added: “We have shown that this technique can kill tumour cells in laboratory conditions. Now it is important to see whether this method could be effective in patients. The next stage will be to develop a clinical trial for the technique with probable targets being liver or skin tumours.”