Heart Failure Post-Myocardial Infarction Promotes Mammary Tumor Growth Through the NGF-TRKA Pathway.

Background: Epidemiological investigations suggest that patients with heart failure have a higher incidence of cancer; however, the causal role of cardiac disease on cancer progression remains unclear.

Objectives: This study aimed to investigate the impact and underlying mechanisms of myocardial infarction (MI)-induced heart failure on tumor cell growth.

Methods: We generated a syngeneic mouse model by implanting mammary tumor-derived 4T1 cells into BALB/c mice with MI resulting from ligation of the left anterior descending artery.

Results: Mice with MI exhibited increased tumor volume, tumor weight, and Ki67-positive proliferative cells in the tumor tissue compared with the sham-operated mice. Furthermore, RNA sequencing analysis in the tumor tissue revealed significant enrichment of pathways related to tumor progression, particularly the PI3K-AKT pathway in the MI mice. Upregulation of tropomyosin receptor kinase A (TRKA) phosphorylation, an upstream regulator of PI3K-AKT signaling, was observed in the tumor tissue of the MI mice. We also observed elevated levels of circulating nerve growth factor (NGF), a ligand of TRKA, and increased NGF expressions in the myocardium after MI. In in vitro experiments, NGF stimulation led to increased cell proliferation, as well as phosphorylation of TRKA and AKT. Notably, inhibition of TRKA by small interfering RNA or the chemical inhibitor GW441756 effectively blocked these effects. Administration of GW441756 resulted in the suppression of tumor volume and cell proliferation in the MI mice.

Conclusions: Our study demonstrates that MI promotes mammary tumor growth through the NGF-TRKA pathway. Consequently, inhibiting TRKA could represent a therapeutic strategy for breast cancer patients concurrently experiencing heart failure after MI.