Abstract
Quercetin is a well-known flavonoid for its potent antitumor and antiproliferative effects on a wide range of human cancer cell lines. However, the delivery of quercetin is challenging due to its extreme insolubility in water. The intention of this study was to evaluate the antitumor effect of quercetin-loaded PEGylated liposomes (PEG-Que-NLs) in vitro and in vivo. We first prepared PEG-Que-NLs by method of thin film hydration; further determined, the optimum ratios of quercetin to Soybean phosphatidylcholine (SPC), to cholesterol (CHL), and to PEG-4000 were 1 : 8, 1 : 2, and 1 : 2 ( w / w ), respectively, and the optimal hydration temperature was 55°C when the mean vesicle diameter and apparent Zeta potential of PEG-Que-NLs were found to be 171.3 ± 10.4 nm and − 13.1 ± 2.1 mV, respectively; the encapsulation efficiency and the drug loading of PEG-Que-NLs were 81.25 ± 3.12 % and 8.5 ± 0.77 % , respectively. Drug release study in vitro showed that PEG-Que-NLs exhibited a slow-release effect without significant burst effect. Furthermore, the inhibition effect of PEG-Que-NLs on HeLa cells was considerably higher than free quercetin (free-Que) and quercetin liposomes (Que-NLs). Intravenous injection of PEG-Que-NLs into U14 bearing mouse models inhibited the cervical carcinoma growth significantly, and the tumor inhibition rate was much higher than free-Que and Que-NLs. These results of this study indicated that PEG-Que-NLs exhibited potential application prospects in the treatment of malignant tumors because of its tumor targeting, slow-release properties, and the solubility improvement of quercetin.
Highlights
Quercetin, as conjugated isoforms bound to alcohol and sugar, could be obtained by the human body through a regular daily diet of fruits and vegetables [1]
Our results showed that PEG-quercetin liposomes (Que-NLs) exhibit significant antitumor effects in vitro and in vivo for the improved solubility and bioavailability of natural quercetin
Soybean phosphatidylcholine and cholesterol are commonly used as liposomes forming materials with ideal biocompatibility; PEG-4000 can weaken the nonspecific protein adsorption capacity of drug loading systems and increase the long-term circulation of drug in vivo, so we choose Soybean phosphatidylcholine, cholesterol, and PEG-4000 to encapsulate quercetin to form PEGQue-NLs
Summary
As conjugated isoforms bound to alcohol and sugar, could be obtained by the human body through a regular daily diet of fruits and vegetables [1]. Recent studies have shown that liposomes coated with inert; biocompatible polymers can evade the recognition of immune cells, so liposomes can be more effectively exposed to tumor tissue [15, 16]. Earlier studies including our previous studies have shown that some nanoparticle formulations of quercetin provide more beneficial in vivo behavior than free quercetin [18, 19], there is still little information about the therapeutic efficacy of quercetin-loaded PEGylated liposomes (PEGQue-NLs) on cervical cancer mice models. Quercetin was encapsulated in the nonaqueous interior of PEGylated liposomes firstly; on the basis of systematic physical and chemical characterization, the anticervical cancer effects of PEG-Que-NLs were subsequently evaluated in vitro and in vivo. Our results showed that PEG-Que-NLs exhibit significant antitumor effects in vitro and in vivo for the improved solubility and bioavailability of natural quercetin. The main content of our study was illustrated in the Graphical Abstract
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