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Updated: Jan 15, 2026
Quantifying Antibody-Dependent Cellular Cytotoxicity in a Tumor Spheroid Model: Application for Drug Discovery
Published on: April 26, 2024
Quantification of timelapse 3D tumor spheroid killing activity of NK cells using a live-cell imaging system
Jakkrapatra Srisantitham1,2, Nontaphat Thongsin1, Siriwal Suwanpitak1
1Siriraj Center for Regenerative Medicine, Research Department, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
Abstract:
Natural killer (NK) cells are critical components of the immune system, responsible for recognizing and eliminating a wide range of abnormal cells, including those infected by pathogens or transformed into cancerous cells. Their potent cytotoxic functions, encompassing the direct release of cytotoxic granules, antibody-dependent cell cytotoxicity (ADCC), and the expression of apoptosis-inducing ligands, make NK cells a promising therapeutic product in cancer immunotherapy. This study presents a detailed protocol for assessing NK cell-mediated cytotoxicity against three-dimensional (3D) tumor spheroids using a live-cell imaging system, offering a more physiologically relevant model compared to traditional 2D cultures. Utilizing this 3D spheroid model, we explored the dynamics of NK cell killing activity against two aggressive solid cancer cell lines, cholangiocarcinoma (KKU-213A) and triple-negative breast cancer (MDA-MB-231), across varying effector-to-target (E:T) ratios. Our findings reveal a dose-dependent increase in NK cell activity, with higher E:T ratios yielding more pronounced tumor cell death. Real-time imaging further demonstrated distinct differences in the morphology and cell death patterns of the two cell lines, with MDA-MB-231 cells exhibiting a faster response to NK cell cytotoxicity. These findings underscore the utility of 3D spheroid models and live-cell imaging for studying NK cell function and advancing the development of NK cell-based immunotherapies. The standardized protocol detailed herein provides a valuable insights into immune surveillance and therapeutic applications.
Insights
Natural killer (NK) cells show increased cancer cell killing activity at higher effector-to-target ratios in a 3D model. This study provides a protocol for assessing NK cell immunotherapy potential using live-cell imaging.
Area of Science:
- Immunology
- Cell Biology
- Cancer Research
Background:
- Natural killer (NK) cells are crucial for immune surveillance and eliminating abnormal cells.
- NK cell cytotoxic functions offer therapeutic potential in cancer immunotherapy.
- Traditional 2D cell cultures lack the physiological relevance of in vivo tumor microenvironments.
Purpose of the Study:
- To present a protocol for assessing NK cell-mediated cytotoxicity against 3D tumor spheroids using live-cell imaging.
- To investigate NK cell killing dynamics against cholangiocarcinoma and triple-negative breast cancer cell lines.
- To evaluate the impact of effector-to-target (E:T) ratios on NK cell activity in a 3D model.
Main Methods:
- Development of a live-cell imaging protocol for NK cell cytotoxicity assays.
- Utilizing 3D tumor spheroids as a physiologically relevant cancer model.
- Testing varying E:T ratios against cholangiocarcinoma (KKU-213A) and triple-negative breast cancer (MDA-MB-231) cell lines.
Main Results:
- NK cell activity demonstrated a dose-dependent increase with higher E:T ratios, leading to enhanced tumor cell death.
- Live-cell imaging revealed distinct morphological and cell death patterns between the two cancer cell lines.
- MDA-MB-231 cells showed a more rapid response to NK cell-mediated cytotoxicity compared to KKU-213A cells.
Conclusions:
- 3D spheroid models and live-cell imaging are valuable tools for studying NK cell function in a more relevant context.
- The developed protocol provides insights into NK cell-mediated immune surveillance and potential therapeutic applications.
- Findings support the advancement of NK cell-based immunotherapies for solid tumors.
