Mechanistically elucidating the in vitro safety and efficacy of a novel doxorubicin derivative

Abstract

Doxorubicin is an effective anticancer drug; however, it is cardiotoxic and has poor oral bioavazilability. Quercetin is a plant-based flavonoid with inhibitory effects on P-glycoprotein (P-gp) and CYP3A4 and also antioxidant properties. To mitigate these therapeutic barriers, DoxQ, a novel derivative of doxorubicin, was synthesized by conjugating quercetin to doxorubicin. The purpose of this study is to mechanistically elucidate the in vitro safety and efficacy of DoxQ. Drug release in vitro and cellular uptake by multidrug-resistant canine kidney (MDCK-MDR) cells were quantified by HPLC. Antioxidant activity, CYP3A4 inhibition, and P-gp inhibitory effects were examined using commercial assay kits. Drug potency was assessed utilizing triple-negative murine breast cancer cells, and cardiotoxicity was assessed utilizing adult rat and human cardiomyocytes (RL-14). Levels of reactive oxygen species and gene expression of cardiotoxicity markers, oxidative stress markers, and CYP1B1 were determined in RL-14. DoxQ was less cytotoxic to both rat and human cardiomyocytes and retained anticancer activity. Levels of ROS and markers of oxidative stress demonstrate lower oxidative damage induced by DoxQ compared to doxorubicin. DoxQ also inhibited the expression and catalytic activity of CYP1B1. Additionally, DoxQ inhibited CYP3A4 and demonstrated higher cellular uptake by MDCK-MDR cells than doxorubicin. DoxQ provides a novel therapeutic approach to mitigate the cardiotoxicity and poor oral bioavailability of doxorubicin. The cardioprotective mechanism of DoxQ likely involves scavenging ROS and CYP1B1 inhibition, while the mechanism of improving the poor oral bioavailability of doxorubicin is likely related to inhibiting CYP3A4 and P-gp.

Pharmacokinetic and Toxicodynamic Characterization of a Novel Doxorubicin Derivative

“…DoxQ was synthesized by conjugating Dox to quercetin via a glycine linker, as previously described [ 14 ].…”

“…For this reason, Dox is only currently available as a parenteral treatment administered intravenously. We have previously reported the synthesis of a Dox-quercetin derivative designed to overcome P–gp efflux and CYP inhibition [ 14 ] as quercetin is a natural flavonoid that exhibits inhibitory effects on CYP3A4 and P–gp [ 15 ] and an antioxidant that scavenges free radicals. Our in vitro investigation of DoxQ [ 14 ] revealed that both Dox and quercetin are released from the conjugate over time.…”

“…We have previously reported the synthesis of a Dox-quercetin derivative designed to overcome P–gp efflux and CYP inhibition [ 14 ] as quercetin is a natural flavonoid that exhibits inhibitory effects on CYP3A4 and P–gp [ 15 ] and an antioxidant that scavenges free radicals. Our in vitro investigation of DoxQ [ 14 ] revealed that both Dox and quercetin are released from the conjugate over time. Furthermore, DoxQ inhibited CYP3A4, a major metabolic enzyme involved in the first pass effect, and demonstrated higher cellular uptake by P–gp-positive (MDCK–MDR) cells compared to free Dox.…”

“…The cardioprotective mechanism of DoxQ involved scavenging ROS, suppression of oxidative stress, and cardiac hypertrophy markers, and also inhibitory effects on CYP1B1, all of which contribute to Dox’s induced cardiotoxicity. Taken together, the in vitro results of DoxQ showed promise at mitigating the cardiotoxicity of Dox and may also mitigate its poor oral bioavailability in vivo by inhibiting CYP3A4 and P–gp [ 14 ]. The antioxidant effects of DoxQ may also mitigate the renal toxicity induced by Dox and improve its overall tolerability in vivo.…”

Antitumour Anthracyclines: Progress and Perspectives

“…In fact, it was demonstrated that this conjugate inhibits CYP3 A4 and induces higher cellular uptake by P‐gp‐positive cells than doxorubicin only, despite the cleavage of the combined structure over time, leading to free quercetin and doxorubicin. There is also evidence to support the antitumoral activity and overall tolerability of doxorubicin‐quercetin complex, as observed in a triple‐negative murine breast cancer cell line, and decreased cardiotoxicity and renal side effects due to the inhibition of oxidative stress and CYP1B1, besides ROS scavenging property …”