Cancer radio-immunotherapy
Nastaran Masoudi Khoram
Institute of Biochemistry and Biophysics (IBB), University of Tehran
Introduction: Radio-immunotherapy uses an antibody labeled with a radionuclide to deliver
cytotoxic radiation to a target cell. In cancer therapy, an antibody with specificity for a
tumor-associated antigen is used to deliver a lethal dose of radiation to the tumor cells. The
ability for the antibody to specifically bind to a tumor-associated antigen increases the dose
delivered to the tumor cells while decreasing the dose to normal tissues. Methods: In the first
study a novel 213Bi-radiolabeled monoclonal antibody (J591) has been constructed that
selectively delivers α-particles to LNCaP prostate cancer cell. In the second study 225Aclabeled monoclonal antibody was used in a mouse model of breast cancer metastases. In the
third study growth inhibition after irradiation was studied with subcutaneous xenografts of
the human ovarian cancer cell line implanted in mice. The animals received an intravenous
injection of 211At-labeled monoclonal antibody (MX35). Results: In vitro study shows that
LNCaP cells kill by 213Bi-J591 proved to be both specific activity dependent and activity
concentration dependent. Other data suggest that 225Ac-labeled monoclonal antibody could
significantly prolong survival in metastatic breast cancer patients. Also tumor growth
decreased after internal irradiation with 211At- labeled antibody. Discussion and conclusion:
In summary, radio-immunotherapy could be used to eradication cancer cells and inhibition
tumor growth. In fact more studies shows that radiolabelled monoclonal antibodies are highly
selective targeting vectors for treatment of some type of cancer but this method requires a
tumor cell to express an antigen that is unique to the cancer cells or is not accessible in
normal cells.
Keywords
Radio-immunotherapy, cancer, monoclonal antibody, radionuclide, antigen
References
[1] J. L. J. Dearling, R. B. Pedley. Technological advances in radio-immunotherapy. Clinical
oncology, (2007) 19: 457-469
[2] Milenic DE, Brady ED, Brechbiel MW. Antibody- targeted radiation cancer therapy.
Nature review drug discovery, (2004) 3: 488-498
1
2