The mechanisms of HER2 targeted ADCs are dependent on Rab GTPases

Area of Science:

• Oncology
• Molecular Biology
• Pharmacology

Background:

• Antibody-drug conjugates (ADCs) are crucial in personalized cancer therapy.
• Understanding ADC intracellular trafficking is key to their mechanism of action.

Purpose of the Study:

• Compare trastuzumab deruxtecan (T-DXd) and ado-trastuzumab emtansine (T-DM1) efficacy.
• Investigate the role of Rab GTPase-regulated intracellular trafficking in ADC efficacy.

Main Methods:

• Assessed T-DXd and T-DM1 efficacy in HER2-positive cell lines.
• Evaluated correlations between ADC efficacy, HER2, and Rab GTPase expression.
• Performed functional studies (knockdown, overexpression, microscopy) to assess Rab GTPase impact on cytotoxicity.

Main Results:

• T-DXd efficacy did not correlate with HER2 expression, unlike T-DM1.
• RAB5A expression correlated with T-DXd efficacy, while RAB5 impacted both ADCs' cytotoxicity.
• RAB4a influenced T-DXd sensitivity, indicating distinct intracellular processing pathways.

Conclusions:

• ADC design significantly influences intracellular trafficking and processing.
• Linker design is a critical factor in determining an ADC's intracellular fate.