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Updated: Jun 14, 2026
Generation of 3D Tumor Spheroids for Drug Evaluation Studies
Published on: February 24, 2023
Pediatric multicellular tumor spheroid models illustrate a therapeutic potential by combining BH3 mimetics with
Vinzenz Särchen1, Senthan Shanmugalingam1, Sarah Kehr1
1Institute for Experimental Cancer Research in Pediatrics, Goethe-University Frankfurt, Frankfurt am Main, Germany.
Abstract:
The induction of apoptosis is a direct way to eliminate tumor cells and improve cancer therapy. Apoptosis is tightly controlled by the balance of pro- and antiapoptotic Bcl-2 proteins. BH3 mimetics neutralize the antiapoptotic function of Bcl-2 proteins and are highly promising compounds inducing apoptosis in several cancer entities including pediatric malignancies. However, the clinical application of BH3 mimetics in solid tumors is impeded by the frequent resistance to single BH3 mimetics and the anticipated toxicity of high concentrations or combination treatments. One potential avenue to increase the potency of BH3 mimetics is the development of immune cell-based therapies to counteract the intrinsic apoptosis resistance of tumor cells and sensitize them to immune attack. Here, we describe spheroid cultures of pediatric cancer cells that can serve as models for drug testing. In these 3D models, we were able to demonstrate that activated allogeneic Natural Killer (NK) cells migrated into tumor spheroids and displayed cytotoxicity against a wide range of pediatric cancer spheroids, highlighting their potential as anti-tumor effector cells. Next, we investigated whether treatment of tumor spheroids with subtoxic concentrations of BH3 mimetics can increase the cytotoxicity of NK cells. Notably, the cytotoxic effects of NK cells were enhanced by the addition of BH3 mimetics. Treatment with either the Bcl-XL inhibitor A1331852 or the Mcl-1 inhibitor S63845 increased the cytotoxicity of NK cells and reduced spheroid size, while the Bcl-2 inhibitor ABT-199 had no effect on NK cell-mediated killing. Taken together, this is the first study to describe the combination of BH3 mimetics targeting Bcl-XL or Mcl-1 with NK cell-based immunotherapy, highlighting the potential of BH3 mimetics in immunotherapy.
Insights
Combining BH3 mimetics with Natural Killer (NK) cell immunotherapy enhances cancer treatment. This approach boosts NK cell cytotoxicity against pediatric tumors, overcoming resistance and improving therapeutic potential.
Area of Science:
- Oncology
- Immunology
- Pharmacology
Background:
- Apoptosis induction is crucial for cancer therapy, regulated by Bcl-2 proteins.
- BH3 mimetics show promise but face resistance and toxicity issues in solid tumors.
- Combining BH3 mimetics with immune-based therapies may overcome apoptosis resistance.
Purpose of the Study:
- To investigate the synergistic effects of BH3 mimetics and Natural Killer (NK) cell immunotherapy in pediatric cancer models.
- To evaluate the efficacy of BH3 mimetics in sensitizing solid tumors to NK cell-mediated cytotoxicity.
- To establish 3D spheroid cultures as a platform for testing drug combinations.
Main Methods:
- Development of pediatric cancer cell spheroid cultures for drug screening.
- Assessment of allogeneic NK cell migration and cytotoxicity within tumor spheroids.
- Evaluation of subtoxic BH3 mimetic concentrations in combination with NK cells.
Main Results:
- Activated NK cells migrated into and killed pediatric cancer spheroids.
- BH3 mimetics targeting Bcl-XL (A1331852) and Mcl-1 (S63845) enhanced NK cell cytotoxicity.
- NK cell-mediated killing was augmented by Bcl-XL and Mcl-1 inhibitors, reducing spheroid size.
- The Bcl-2 inhibitor ABT-199 did not enhance NK cell activity.
Conclusions:
- This study introduces a novel combination of BH3 mimetics and NK cell immunotherapy.
- BH3 mimetics targeting Bcl-XL or Mcl-1 can potentiate NK cell anti-tumor activity.
- This combination strategy holds significant potential for treating pediatric malignancies.
