Chen_2024_Toxicology__153757

Doxorubicin (DOX) is a widely used antitumor agent; however, its clinical application is limited by dose-related organ damage. Because organic cation/carnitine transporters (OCTN1 and OCTN2), which are critical for DOX uptake, are highly expressed in hepatocytes, we aimed to elucidate the role of these transporters in hepatic DOX uptake. The results indicated that inhibitors and RNA interference both significantly reduced DOX accumulation in HepG2 and HepaRG cells, suggesting that OCTN1/2 contribute substantially to DOX uptake by hepatocytes. To determine whether metformin (MET, an inhibitor of OCTN1 and OCTN2) ameliorates DOX-induced hepatotoxicity, we conducted in vitro and in vivo studies. MET (1-100microM) inhibited DOX (500nM) accumulation and cytotoxicity in vitro in a concentration-dependent manner. Furthermore, intravenous MET administration at 250 or 500mg/kg or by gavage at 50, 100, or 200mg/kg reduced DOX (8mg/kg) accumulation in a dose-dependent manner in the mouse liver and attenuated the release of alanine aminotransferase, aspartate aminotransferase, and carboxylesterase 1. Additionally, MET reduced the distribution of DOX in the heart, liver, and kidney and enhanced the urinary elimination of DOX; however, it did not increase the nephric toxicity of DOX. In conclusion, our study demonstrated that MET alleviates DOX hepatotoxicity by inhibiting OCTN1- and OCTN2-mediated DOX uptake in vitro (mouse hepatocytes and HepaRG or HepG2 cells) and in mice.