Target-seeking molecule offers cancer treatment options
cancer tumours is set to improve detection and treatment of the
killer disease, which is a lot more successful if therapy begins at
an earlier stage.
The molecule, termed an affibody has been developed that binds to the protein HER-2, which primarily occurs in cancer cells from patients with aggressive forms of breast cancer.
The scientists have attached radioactivity to the affibody molecules, so that they can visualise tumours and metastases and also treat tumours with the local dose of radiation provided by this radioactivity.
Affibody molecules are tiny, which enables them to enter tumours and be rapidly distributed in the body, unlike antibodies, which are normally used in target-seeking therapy and visualisation.
In addition, affibody molecules are easy to develop for virtually any target and can therefore in all probability be used for visualising and treating many different forms of cancer.
The research involved the development of an affibody molecule that binds to the protein HER-2, which primarily occurs in cancer cells from patients with aggressive forms of breast cancer.
The scientists have attached radioactivity to the affibody molecules, so that they can visualise tumours and metastases and also treat tumours with the local dose of radiation provided by this radioactivity.
Head researcher Ann-Charlott Steffen demonstrated that the HER-2-binding affibody molecules attach to cancer cells with the HER-2 target on their surface, both in cell cultures and in mouse tumours.
The research team has also found that the radioactivity in mouse tumours can be used to make these tumours visible in a gamma camera (see picture). Moreover, the results show that the radioactivity delivered by the affibody molecules can be used to kill tumour cells in cell cultures.
"I hope these findings will lead to new possibilities of visualising and treating distributed tumour diseases so that more cancer patients will be able to survive," said researcher Ann-Charlott Steffen.
Current treatments include surgery, chemotherapy, and radiation. Surgery is most effective for large, well-defined tumours, but if the disease has spread, chemotherapy and/or radiation are needed.
These forms of treatment affect all dividing cells, leading to toxic effects on healthy tissue. This toxicity limits the size of the dose that can be given, thereby also limiting the probability that the disease will be cured.
By seeking out tumour cells and selectively delivering cytostatics or radiation to the cancer cells, the dose affecting healthy tissue can be reduced and the dose to the tumour can be increased. This improves the chances of curing the disease.
The research has been shown in a dissertation by Ann-Charlott Steffen to be publicly defended at >Uppsala University on April 22.
