Antibodies can target cancer proteins inside cells, say Singapore researchers

In collaboration with the Press Association

Scientists in Singapore have suggested that antibody-based therapies can be used to target proteins inside cancer cells, overturning the traditional view that only proteins on the surface of cells can be targeted.

The discovery could help to expand the scope of antibody-based cancer therapy.

Researchers at the Agency for Science, Technology and Research (A*STAR) have been looking at ways of using the tumour-fighting properties of antibodies, which are often used alongside therapies like chemotherapy and radiotherapy to target cancerous cells.

At present, antibodies are used to target proteins found on the surface of cancer cells - they bind to and block the action of such proteins. Several cancer drugs are antibodies, including bevacizumab (Avastin) and trastuzumab (Herceptin).

But until now antibodies were widely considered to be too big to enter cancer cells and attack the cancer-causing proteins found inside.

This has limited the scope of antibody-based drug development to target only external proteins.

However, research by Qi Zeng and colleagues at A*STAR has identified three different antibodies that can slip inside cancer cells and bind to proteins. The work in lab models also shows that the three antibodies trigger an immune response against certain tumours - working in much the same way as a traditional vaccine.

The researchers did not determine exactly how the antibodies were able to enter the cell, but found that immune system components called B cells may be involved. This will be the subject of future research.

Oliver Childs, senior science information officer at Cancer Research UK, said: "This work is an early hint that we might be able to expand the use of antibody-based therapies to target proteins inside tumour cells, but more research is needed before we can be sure.

"We also need to know exactly how antibodies reach targets within tumour cells, as understanding this mechanism could help us to improve future treatments. It will be interesting to see whether this early work translates into new antibody treatments."

Copyright Press Association 2011

References

  • Guo, K. et al. Targeting Intracellular Oncoproteins with Antibody Therapy or Vaccination. Science Translational Medicine. Vol 3 Issue 99