Proteomic signatures of doxorubicin-induced lymphatic dysfunction in tumor-bearing rats

Doxorubicin (DOX) is widely used to treat breast and gynecological cancers; however, it is associated with several toxicities, including the development of lymphedema. Lymphedema is the accumulation of fluid in the tissues due to impaired lymphatic drainage. We have shown that DOX inhibits the rhythmic pumping of isolated lymphatic vessels (LVs) and reduces lymph flow in vivo through activation of ryanodine receptors and disruption of calcium homeostasis. The mechanism by which DOX activates RyRs in LVs is unclear. We used discovery proteomics to better understand the potential molecular mechanisms of DOX-induced contractile anomalies and RyR activation in LVs from tumor-bearing female Fisher 344 rats. Atotal of 4584 proteins were detected, with 298 proteins upregulated and 314 proteins downregulated (log2 < 0.05) by DOX treatment. While RyR protein remained unchanged, several proteins that regulate RyR action (e.g., calmodulin, parvalbumin, SOD2) were upregulated. Other proteins known to be involved in contraction and pacing mechanisms in lymph vessels were also upregulated (myosin, endothelin 1 receptor, Ano1, Ca2+ activated Cl- channel, Ca2+ activated K+ channel). Further evaluation and validation of these targets are needed to develop novel therapeutics to prevent DOX-induced lymphatic dysfunction