The Functional Crosstalk between HER2 Tyrosine Kinase and TGF-β Signaling in Breast Cancer Malignancy

Abstract EN

Accumulating evidence indicates a functional crosstalk between the HER2 (ErbB2) tyrosine kinase and the TGF-β signaling mediated by its serine/threonine kinase receptors.

In HER2-overexpressing breast cancer, this crosstalk results in increased cancer cell proliferation, survival and invasion, accelerated cancer progression and metastasis in animal models, and resistance to chemotherapy and HER2-targeted therapy.

The transformed cellular context with constitutively active HER2 signaling, as a consequence of HER2 gene amplification or overexpression, converts TGF-β from a tumor suppressor to a malignancy-promoting factor.

TGF-β, in turn, potentiates oncogenic HER2 signaling by inducing shedding of the ErbB ligands and clustering of HER2 with integrins.

In addition, TGF-β is associated with resistance to trastuzumab, an anti-HER2 therapeutic antibody.

Recent mechanistic studies indicate that TGF-β and HER2 cooperate through both Smad-dependent and independent mechanisms.

Blockade of HER2:TGF-β crosstalk may significantly enhance the efficiency of conventional therapies in breast cancer patients with HER2 overexpression.