3D Culture Represents Apoptosis Induced by Trastuzumab Better than 2D Monolayer Culture

Area of Science:

• Oncology
• Cell Biology
• Pharmacology

Background:

• Three-dimensional (3D) cell culture may better mimic in vivo conditions compared to 2D culture for evaluating drug responses.
• Investigating differential responses to trastuzumab based on PIK3CA mutation status is crucial for personalized breast cancer therapy.

Purpose of the Study:

• To compare the efficacy of 3D versus 2D cell culture models in representing in vivo responses to trastuzumab in breast cancer cell lines with varying PIK3CA genotypes.
• To assess the impact of PIK3CA mutation status on trastuzumab-induced apoptosis and cell signaling.

Main Methods:

• Western blot analysis was used to evaluate apoptosis and cell signaling proteins.
• Four HER2-amplified breast cancer cell lines were cultured in both 3D and 2D formats.
• Cells were treated with trastuzumab alone and in combination with BKM120 (a PI3K inhibitor).

Main Results:

• 3D culture demonstrated increased trastuzumab-induced apoptosis (cleaved PARP) in PIK3CA-wild-type cells, an effect not seen in 2D culture.
• The p-AKT/AKT ratio decrease upon trastuzumab treatment was more pronounced in PIK3CA-wild-type cells in 3D culture.
• Combined treatment with BKM120 and trastuzumab enhanced apoptosis compared to single-agent treatment.

Conclusions:

• 3D cell culture provides a more accurate model for studying trastuzumab-induced apoptosis and resistance mechanisms related to PIK3CA mutations in breast cancer.
• These findings support the use of 3D culture systems for preclinical evaluation of targeted therapies in breast cancer.