Could this protein duo be the key to overcoming breast cancer resistance? Insights from a new study

A groundbreaking study from the University of Liverpool has unveiled critical insights into breast cancer, particularly focusing on drug resistance mechanisms. The research highlights how two vital proteins, HER2 and aVb6 integrin, play a crucial role in the survival and spread of HER2-positive breast cancer, one of the most aggressive forms of the disease.

Previously, HER2 and aVb6 integrin were recognized for independently predicting cancer outcomes. However, this study reveals their collaboration through a newly identified ‘crosstalk’ mechanism that drives cancer cell invasion. This discovery is particularly significant as it may explain why some breast cancers become resistant to trastuzumab, a common treatment for HER2-positive cases.

Utilizing advanced proteomic analysis, the research team found that when aVb6 integrin is activated, it recruits HER2 along with a network of molecules, including RAB5, RAB7A, and GDI2. This network facilitates direct communication between the proteins, controlling their movement within cells and triggering signals that promote cancer progression. In contrast, trastuzumab-resistant breast cancer cells exhibit a breakdown of this intricate network, losing the crucial regulator GDI2. This disruption impairs the aVb6-HER2 connection, enabling the cancer to adapt and invade through alternative pathways, rendering existing therapies ineffective.

Furthermore, the study links these molecular interactions to patient outcomes. Higher levels of GDI2 correlate with improved survival rates, while increased aVb6 expression indicates a higher likelihood of relapse post-trastuzumab treatment. This positions aVb6 as a promising biomarker for identifying patients at risk of treatment failure, as well as a potential target for new therapies aimed at overcoming resistance.

Dr. Mark Morgan, the lead researcher, emphasizes the importance of these findings in understanding how breast cancer invades tissues and develops resistance to targeted treatments. By targeting the RAB5/RAB7A/GDI2 network or restoring its normal function, it may be possible to prevent or delay the onset of resistance in HER2-positive breast cancers.

The research not only enhances our understanding of cancer biology but also offers a roadmap for developing innovative strategies to combat drug resistance, potentially leading to more personalized and effective treatments for patients.