Detection of apoptosis in cancer cell lines using Surface Plasmon Resonance imaging

Induction of apoptosis in cancer cells by therapeutic agents is an important event to detect the potential effectiveness of therapies. Here we explore the potential of Surface Plasmon Resonance imaging (SPRi) to assess apoptosis in cancer cells exposed to therapeutic agents by measuring the cytochrome C release of apoptotic cells. Spots on the SPR sensor were coated with anti-cytochrome C, anti-EpCAM, anti-CD49e monoclonal antibodies and combinations thereof. Cells from the breast cancer cell line MCF7 were introduced into a flow cell, captured on a sensor surface and exposed to culture medium with and without paclitaxel. The cells were followed for 72 h. Clear SPRi responses were observed on the anti-EpCAM coated spots, indicating binding of the MCF7 cells with strong time and drug presence dependent increases in SPRi responses on the spots coated with both anti-EpCAM as well as anti-cytochrome C. This suggests a release of cytochrome C by the MCF7 cells in these specific locations. In addition offline experiments were performed where cultured MCF7 cells were exposed to complete culture medium with paclitaxel, Trastuzumab antibody and Trastuzumab T-DM1 (an antibody drug conjugate). The supernatant of these cells was analyzed and also their drug concentration dependent cytochrome C presence was detected. These preliminary results suggest SPRi to be a unique tool to measure real time response of cancer cells exposed to drugs or drug combinations.