A Facile, Transfection-Free Approach to siRNA Delivery in In Vitro 3D Spheroid Models.

Area of Science:

• Biotechnology
• Cell Biology
• Drug Discovery

Background:

• Conventional two-dimensional (2D) cell cultures inadequately model in vivo complexity, leading to poor translation of drug candidates.
• Three-dimensional (3D) spheroid models offer greater physiological relevance, mimicking tumor architecture and drug resistance.
• RNA interference (RNAi) is crucial for target identification, but its application in 3D models is limited.

Purpose of the Study:

• To demonstrate efficient RNA interference (RNAi)-mediated gene knockdown in various 3D spheroid models.
• To establish a transfection-free RNAi methodology applicable to both matrix-free and matrix-embedded 3D cultures.
• To facilitate the discovery of novel druggable targets with enhanced clinical relevance.

Main Methods:

• Utilized Dharmacon Accell siRNAs for transfection-free RNAi in three distinct 3D spheroid models.
• Investigated RNAi efficiency in both matrix-free and extracellular matrix-embedded spheroid cultures (Matrigel and GrowDex).
• Developed protocols for siRNA delivery, spheroid collection, and subsequent RNA/protein extraction for knockdown validation.

Main Results:

• Achieved efficient RNAi-mediated gene knockdown in all tested 3D spheroid models.
• Demonstrated the versatility of the transfection-free siRNA approach across different 3D culture formats.
• Successfully characterized gene knockdown at the RNA and protein levels.

Conclusions:

• The developed transfection-free RNAi method is effective for gene knockdown in complex 3D spheroid models.
• This methodology enables scalable screening for identifying novel drug targets with improved clinical predictivity.
• Advances preclinical drug development by bridging the gap between 2D and in vivo models.