The human amniotic fluid stem cell secretome effectively counteracts doxorubicin-induced cardiotoxicity.

The anthracycline doxorubicin (Dox) is widely used in oncology, but it may cause a cardiomyopathy with bleak prognosis that cannot be effectively prevented. The secretome of human amniotic fluid-derived stem cells (hAFS) has previously been demonstrated to significantly reduce ischemic cardiac damage. Here it is shown that, following hypoxic preconditioning, hAFS conditioned medium (hAFS-CM) antagonizes senescence and apoptosis of cardiomyocytes and cardiac progenitor cells, two major features of Dox cardiotoxicity. Mechanistic studies with mouse neonatal ventricular cardiomyocytes (mNVCM) reveal that hAFS-CM inhibition of Dox-elicited senescence and apoptosis is associated with decreased DNA damage, nuclear translocation of NF-kB, and upregulation of the NF-kB controlled genes, Il6 and Cxcl1, promoting mNVCM survival. Furthermore, hAFS-CM induces expression of the efflux transporter, Abcb1b, and Dox extrusion from mNVCM. The PI3K/Akt signaling cascade, upstream of NF-kB, is potently activated by hAFS-CM and pre-treatment with a PI3K inhibitor abrogates NF-kB accumulation into the nucleus, modulation of Il6, Cxcl1 and Abcb1b, and prevention of Dox-initiated senescence and apoptosis in response to hAFS-CM. These results support the concept that hAFS are a valuable source of cardioprotective factors and lay the foundations for the development of a stem cell-based paracrine treatment of chemotherapy-related cardiotoxicity.