Sympathetic β2-adrenergic receptor blockade overcomes docetaxel resistance in prostate cancer

Abstract

Purpose: Due to the limited effective therapies, resistance to docetaxel is ordinarily fatal and remains a critical clinical challenge.β2-adrenergic receptor(β2-AR)can promote the metastasis and invasion of prostate cancer, but the role in chemotherapy-resistant prostate cancer remains unclear.

Methods: By downloading the GEO database in NCBI, the expression of β2-AR in different prostate tissues was analyzed. We constructed docetaxel-resistant prostate cancer cell lines by the method of dose-escalation. LC3B-labeled stable cells and shAtg5 knockdown stable cells were constructed by lentivirus infection. The molecular mechanism of β2-AR affecting docetaxel sensitivity through apoptosis and autophage were investigated by flow cytometry, mitochondrial membrane potential and western blot. Then we detected the interaction between autophagy and apoptotic by performing immunoprecipitation assay.

Results: We show that restraining the activity of β₂-AR sensitized the cell response and reduced the resistance to docetaxel. The mechanism involves the regulation of β₂-AR in the cellular response to docetaxel through apoptosis and autophagy via caspase signaling and Atg5/AMPK/mTOR pathway as well as the effect of β₂-AR on the crosstalk between apoptosis and autophagy via p38 MAPK and JNK/c-Jun/FOXO3a signaling pathways.

Conclusion: Our data demonstrate that β₂-AR inhibitor-induced autophagy and apoptosis contribute to the effectiveness responses to docetaxel in castration-resistant prostate cancer, and in combination with pharmacological agents of β₂-AR and autophagy inhibitors may provide a potential therapeutic strategy to enhance the limited capacity of docetaxel to control castration-resistant prostate cancer.

Keywords: Apoptosis and autophagy; Chemotherapy resistance; Prostate cancer; β(2)-adrenergic receptor.