Antibody Penetration and Efficacy in 3D Tumor Spheroid Models
Early drug development is at the forefront of cancer research, driving innovative treatments and advancements, but it also faces significant hurdles. A major challenge stems from the lack of robust preclinical models capable of accurately assessing both the efficacy and safety of initial drug candidates while maintaining high translational relevance.
To address this gap, InSphero has developed 3D InSightâ„¢ Tumor Microtissues that closely mimic the complexity and heterogeneity of the tumor microenvironment. The 3D tumor microtissues are aggregated in large batches with high well-to-well and plate-to-plate uniformity in specially designed 384-well plates compatible with automation and high-throughput analysis. The 3D InSightâ„¢ Tumor Microtissue model maintains uniform composition and size between spheroids, offering a highly reliable and scalable 3D in vitro tumor platform for drug discovery, screening, and preclinical evaluation.
Therapeutic antibodies represent a promising class of targeted anticancer agents that can suppress tumor cell activity or harness the immune system to promote tumor killing. However, some functional constraints have come to light, such as limited tumor penetration and heterogenous distribution within the tumor, impacting their effectiveness. We have developed a high-content imaging-based screening assay to quantify spatial antibody penetration into tumor microtissues.
3D InSightâ„¢ Tumor Microtissues were treated with therapeutic antibodies for 5 minutes up to 24 hours before fixation and undergoing our proprietary 3D immunofluorescence protocol. With this protocol, we were able to specifically detect the therapeutic antibody and to image entire spheroid cross-sections across their z-stack while maintaining a high resolution at the center of the spheroid. Additionally, InSphero has developed a high-content image analysis pipeline that automatically quantifies the number of antibody-bound positive cells and their distribution within the 3D tumor microtissues, allowing the determination of the penetration depth of the antibody.
Using this assay, we are able to highlight that different therapeutic antibodies have variable penetration depth, kinetics, and tumor distribution. We demonstrated that the therapeutic modality with the highest target affinity is able to penetrate faster, deeper and is more evenly distributed within the 3D InSightâ„¢ tumor spheroids, while the therapeutic modality with the lowest target affinity had a fast turnover.
Thus, 3D InSightâ„¢ Tumor Microtissues, which combine high physiological relevance and scalability, allow reliable, accurate, and simultaneous assessment of therapeutic antibody penetration and efficacy to empower cancer drug discovery.
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