β2‐AR activation induces chemoresistance by modulating p53 acetylation through upregulating Sirt1 in cervical cancer cells

It has been suggested that β2-adrenergic receptor (β2-AR)-mediated signaling induced by catecholamines regulates the degradation of p53. However, the underlying molecular mechanisms were not known. In the present study, we demonstrated that catecholamines upregulated the expression of silent information regulator 1 (Sirt1) through activating β2-AR-mediated signaling pathway, since selective β2-AR antagonist ICI 118, 551 and non-selective β-blocker proprenolol effectively repressed isoproterenol (ISO)-induced Sirt1 expression. Catecholamines inhibited doxorubicin (DOX)-induced p53 acetylation and transcription-activation activities by inducing the expression of Sirt1. Knockdown of the Sirt1 expression by the specific siRNA remarkably blocked the inhibitory effects of ISO on DOX-induced p53 acetylation. In addition, we demonstrated that catecholamines induced resistance of cervical cancer cells to chemotherapeutics both in vitro and in vivo and that β2-AR was overexpressed in cervical cancer tissues. Our data suggest that the p53-dependent, chemotherapeutics-induced cytotoxicity in cervical cancer cells may be compromised by catecholamines-induced upregulation of the Sirt1 expression through activating the β2-AR signaling.