Quercetin-loaded Liposomes Effectively Induced Apoptosis and Decreased the Epidermal Growth Factor Receptor Expression in Colorectal Cancer Cells: An In Vitro Study

Abstract

Background: Quercetin is a flavonoid having anti-cancer properties; however, it has low stability, insufficient bioavailability, and poor solubility. This study aimed to load quercetin on nanoliposomes to enhance its efficiency against SW48 colorectal cancer cells. The cytotoxicity of free-quercetin and quercetin-loaded nanoliposomes on the expression of the epidermal growth factor receptor (EGER) gene was investigated.

Methods: This present in vitro study was conducted at Yasuj University of Medical Sciences (Yasuj, Iran) in 2021. In this in vitro study, the lipid thin-film hydration method was used to synthesize quercetin-loaded liposomes. Additionally, high-performance liquid chromatography (HPLC) analyses, dynamic light scattering (DLS), and transmission electron microscopy (TEM) investigations were used to characterize nanomaterials. Following that, MTT, flow cytometry, and real-time PCR were used to investigate the cytotoxicity of quercetin-loaded liposomes on the colorectal cancer cells SW48 cell line, the incidence of apoptosis, and the expression of the EGFR gene in these cells. Statistical analysis was performed using the SPSS (version 26.0), and the graphs were created with the GraphPad Prism version 8.4.3. P<0.05 was considered statistically significant.

Results: The nanoparticles were spherical, homogenous, and 150±10 nm in size. According to HPLC, Quercetin had a 98% loading capacity. Although both free quercetin and quercetin-loaded liposomes indicated significant cytotoxicity against cancer cells (P˂0.001), the combined form was significantly more active (P=0.008). 50 µg/mL of this compound reduced the viability of SW48 cells by more than 80% (IC₅₀ 10.65 µg/mL), while the viability of cells treated with free quercetin was only 66% (IC₅₀ 18.74 µg/mL). The apoptosis was nearly doubled in the cells treated with quercetin-loaded nanoliposomes compared to free quercetin (54.8% versus 27.6%). EGFR gene expression, on the other hand, was significantly lower in cells treated with quercetin-loaded liposomes than the quercetin alone (P=0.006).

Conclusion: When combined with nanoliposomes, quercetin had greater anti-proliferative, apoptotic, and anti-EGFR expression than free quercetin.

Keywords: Colorectal neoplasms; ErbB receptors; Lipids; Nanoparticles; Neoplasms; Quercetin.