Induced Breast Cancer Cell Apoptosis by Synchrotron-Based Irradiation with Monochromatic Microbeams

Breast cancer is the most common female malignancy and has the second highest cancer related mortality in western women. Radiotherapy (RT) plays an important role in the modern breast cancer management of all stages. However, the efficiency of conventional RT continues to be limited because the treatment induces radio-toxicity in healthy tissues. In this work, we present the feasibility studies of the monochromatic micro-beam therapy (m-MRT) technique, a novel synchrotron based radiotherapy concept that uses high brilliance, monochromatic X-ray micro-beams smaller than 200 microns, applied to treat breast cancer tissue and cell samples. Two different energies were used for those tests: 50 keV and 100 keV. The tumor fragments and cells samples were irradiated ex-situ and then analyzed to assess the damages induced by m-MRT irradiation. Eight patient derived xenografted (PDX) tumor fragments were irradiated and implanted in live NOD Severe Combined Immuno-deficient (SCID) gamma (NSG) mice to assess the effect of irradiation on tumor growth comparing to the control. The pilot studies showed that the m-MRT treatment of cancerous tissue slowed down the tumor growth in (NSG) mice as compared to untreated controls. The biomolecule analysis demonstrated that the irradiation induced cancer cell apoptosis by triggering a stress response of the cells at radiation dose of 60 Gy or higher. Future studies will investigate how the cancer cells respond to the irradiation treatment in vivo in the live animals.