In vitro characterization of reagents efficacy in the context of cancer immunotherapy for solid tumors is a necessary step before moving to more expensive animal models and clinical studies. However, current in vitro assays are difficult to implement in high throughput environment and are mainly based on end point methodologies that are unable to capture the full dynamic of the immune response. Here we present the adaptation of an impedance-based platform to monitoring cytotoxic activity of immune cells activated trough different means. The technology detects cell death and proliferation of adherent cells by measuring changes in conductance of microelectrodes embedded in 96 and 384-wells cell culture plates. We utilized adherent cell lines and primary tumor cells with different expression levels of the EpCAM antigen, which is currently under evaluation as a target for cancer immunotherapy. Using PBMCs as effector cells and combinations of EpCAM/CD3 BiTE we demonstrated the suitability of such impedance-based approach to quantitatively monitor the efficacy of immune cells-mediated cancer cell killing both under different effector:target ratios and antibody concentrations. Combination treatments with checkpoint inhibitors were also effective when evaluated with the same approach. Finally, we validated the technology with engineered Car-T cells directed against common antigens expressed in tumors. Overall, our results demonstrate the value of such approach in measuring the cytotoxic response across the temporal scale, an aspect that is otherwise very difficult to assess with more canonical end point assays like Chromium 51 release or ATP-based luminescence. Furthermore, the availability of 384-wells format and minimal sample handling place the technology in an ideal spot for applications in personalized medicine, like therapeutic protocol validation directly on patient samples.
Citation Format: Fabio Cerignoli, Biao Xi, Garret Guenther, Trent Rector, Lincoln Muir, Leyna Zhao, Yama Abassi. In vitro testing solid cancers immunotherapy protocols through impedance technology allows dynamic and label-free evaluation of immune response and reagent efficacy [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B093.
- ©2016 American Association for Cancer Research.