Mutant HER2 needs mutant HER3 to be an effective oncogene

Area of Science:

• Oncology
• Molecular Biology
• Cancer Genetics

Background:

• The human epidermal growth factor receptor 2 (HER2) pathway is implicated in various cancers.
• HER3 is a catalytically inactive homolog of HER2, often co-expressed and interacting with HER2.
• Mutations in receptor tyrosine kinases can lead to aberrant signaling and oncogenesis.

Purpose of the Study:

• To investigate the functional consequences of co-occurring mutations in HER2 and HER3.
• To elucidate the mechanism by which these mutations promote oncogenic signaling.
• To understand the synergistic effects of HER2 and HER3 mutations on signaling complex formation and activity.

Main Methods:

• Analysis of co-occurring missense mutations in HER2 and HER3 from patient tumor datasets.
• In vitro kinase assays to assess the activity of mutated HER2 and HER3.
• Cell-based assays to evaluate signaling downstream of the HER2/HER3 complex.
• Co-immunoprecipitation studies to examine HER2/HER3 complex formation.

Main Results:

• Co-occurring missense mutations in HER2 and HER3 were identified in several cancer types.
• Mutations in both HER2 and HER3 synergistically enhanced the oncogenic signaling output of the HER2/HER3 complex.
• The catalytically inactive HER3 mutations appeared to stabilize the active conformation of HER2, promoting sustained signaling.

Conclusions:

• Co-occurring mutations in HER2 and HER3 represent a novel mechanism for oncogenic signaling.
• Targeting the HER2/HER3 complex, particularly in the context of these mutations, may offer therapeutic strategies.
• Understanding the interplay between mutated HER2 and HER3 is crucial for developing effective cancer treatments.