Perorally active nanomicellar formulation of quercetin in the treatment of lung cancer

Abstract

Background: Realizing the therapeutic benefits of quercetin is mostly hampered by its low water solubility and poor absorption. In light of the advantages of nanovehicles in the delivery of flavanoids, we aimed to deliver quercetin perorally with nanomicelles made from the diblock copolymer, polyethylene glycol (PEG)-derivatized phosphatidylethanolamine (PE).

Methods: Quercetin-loaded nanomicelles were prepared by using the film casting method, and were evaluated in terms of drug incorporation efficiency, micelle size, interaction with Caco-2 cells, and anticancer activity in the A549 lung cancer cell line and murine xenograft model.

Results: The incorporation efficiency into the nanomicelles was ≥88.9% when the content of quercetin was up to 4% w/w, with sizes of 15.4-18.5 nm and polydispersity indices of <0.250. Solubilization of quercetin by the nanomicelles increased its aqueous concentration by 110-fold. The quercetin nanomicelles were stable when tested in simulated gastric (pH 1.2) and intestinal (pH 7.4) fluids, and were non-toxic to the Caco-2 cells as reflected by reversible reduction in transepithelial electrical resistance and ≤25% lactose dehydrogenase release. The anticancer activity of quercetin could be significantly improved over the free drug through the nanomicellar formulation when tested using the A549 cancer cell line and murine xenograft model. The nanomicellar quercetin formulation was well tolerated by the tumor-bearing animals, with no significant weight loss observed at the end of the 10-week study period.

Conclusion: A stable PEG-PE nanomicellar formulation of quercetin was developed with enhanced peroral anticancer activity and no apparent toxicity to the intestinal epithelium.

Keywords: PEG-PE; lung cancer; peroral drug delivery; polymeric micelles; quercetin.

Figure 1

MTT viability of free (□) and nanomicellar (■) quercetin in A549 human lung cancer cell line upon 72 hours of exposure.

Figure 2

Stability of quercetin nanomicelles in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF).

Figure 3

Interaction of quercetin nanomicelles with Caco-2 cells. (Panel A)Cellular accumulation of FITC-labeled nanomicelles over 24 hours of incubation at 37°C Representative images from fluoresence confocal microscopy are shown. (Panel B) Change in TEER upon treatment with quercetin in free (green) and nanomicellar (orange) forms, as well as empty nanomicelles (blue) and 1% triton-X (red), with the arrow indicating treatment duration of 24 hours. Notes: ⁺, ^#, *, and ^‡ represent P < 0.05 compared to values at t = 0 hours.

Figure 4

LDH cytotoxicity in Caco-2 cells when treated with free (□) and nanomicellar (■) quercetin for 24 hours.

Figure 5

In vivo efficacy of orally given quercetin nanomicelles in subcutaneous A549 lung tumor xenograft murine model. Mice (n = 6) were treated with 30 mg/kg quercetin three times per week for 3 weeks by oral gavage, with treatment given in 3, 4, and 5 weeks post tumor inoculation. Study groups included untreated control ( ), quercetin in ethanol-based suspension (□) or nanomicelles (■). Notes: *represents P < 0.05 compared to control and quercetin oral suspension.