Xu, Jianxiang

Background: Doxorubicin (DOX) is an effective chemotherapy but limited by severe cardiotoxicity. Chemokine receptors CXCR4 and CXCR7 are involved in regulating cardiac survival, inflammation, and fibrosis, yet their specific roles in DOX-induced cardiotoxicity (DICT) remain unclear. Objective: We investigated the cardioprotective effects of TC14012, a dual-target CXCR4 antagonist and CXCR7 agonist, against DICT. Methods: Male C57BL/6J mice received chronic or acute DOX administration with twice-weekly TC14012 treatment. Cardiac function was evaluated by echocardiography. Markers of cardiac fibrosis and inflammation were assessed. RNA-seq analysis was performed to explore associated molecular pathways. Key pathways were validated in cardiac cells and bone marrow-derived mast cells. Results: TC14012 significantly improved cardiac function, indicated by preservation of ejection fraction and fractional shortening, and increased survival rates optimally at 5 mg/kg, which were accompanied with reductions in cardiac collagen deposition and infiltration of macrophages and neutrophils. RNA-seq revealed that TC14012 protecting against DICT was associated with a remarkable stimulation of signals involving in cardiac contraction and energy reserve metabolism processes, particularly glycogen and glucan metabolism that are crucial for meeting the cardiac energy demand in response to DOX induction. These signals could be further enriched into AMPK signalling pathway and validated by enhancement of cardiac AMPK phosphorylation both in vivo and in vitro . Meanwhile, TC14012’s cardioprotective effects were accompanied by a reduction in signals involving in cardiac mast cell activation and degranulation, which could be enriched into Rap1 signalling pathway and validated by TC14012 inhibiting mast cell activation and Rap1-GTP activity in vitro . Importantly, TC14012 did not compromise DOX’s antitumor efficacy in EL-4 lymphoma-bearing mice. Conclusions: TC14012 may prevent DICT by activating CXCR7-AMPK signalling to reprogram cardiomyocyte metabolism and antagonizing CXCR4-Rap1 signalling to blunt mast cell-mediated sentinel effects without compromising the anticancer efficacy DOX.

Background: Doxorubicin (DOX)-induced cardiotoxicity (DICT) has become a serious health burden for cancer survivors. The detrimental effects of CXCR4-mediated excessive inflammation in myocardium and the protective effects of CXCR7 in cardiomyocytes have been demonstrated. Aims: We tested the protective effects against DICT of a dual-targeting compound TC14012, which has specific antagonistic activity against CXCR4 and potent agonistic activity on CXCR7. Methods: Eight-week-old male C57BL/6J mice were injected with DOX for consecutive 5 weeks, during which mice were treated with TC14012 twice a week. One week after the last dose injection, mice were euthanized after heart function examination. Markers of cardiac inflammation and fibrosis were evaluated. Cardiac RNA-seq was performed to explore the underlying molecular pathways. Key findings: TC14012 supplement significantly prevented DOX-induced cardiac systolic dysfunction, reflected by improved ejection fraction and fraction shortening, along with remarkable attenuation of DOX-induced cardiac perivascular and interstitial collagen deposition and neutrophils and macrophage infiltration. RNA-seq revealed that TC14012 prevention of DICT was accompanied with a remarkable stimulation of signals involving in cardiac contraction and energy reserve metabolic process, particularly glycogen and glucan metabolism that are crucial for meeting the cardiac energy demand in response to DOX induction. These signals could be further enriched into AMPK signaling pathway and validated by upregulation of AMPK phosphorylation. Besides, TC14012 prevention of DICT was accompanied with a significant reduction in cardiac mast cell activation and degranulation. These signals could be further enriched into Rap1 signaling pathway, and TC14012 was validated to inhibit Rap1 activity and mast cell activation. Most importantly, TC14012 treatment did not affect the suppressive effects of DOX on tumor growth in a syngeneic EL4 lymphoma-bearing, immunocompetent mouse model. Conclusions: We preliminary conclude that TC14012 prevents DICT by activating cardiac CXCR7 to reprogram cardiomyocyte metabolism and prevent cardiac damage and dysfunction via activating AMPK, and by antagonizing CXCR4 to inhibit cardiac mast cell infiltration and activation via blunting Rap1 activity but does not affect the anti-tumor activity of DOX.