Responsiveness of glycyrrhetinic acid modified liposome toward secretory phospholipase A 2 and its growth inhibitory in Colo205 cells

This study aimed to design a novel liposome containing GA modified phosphatidylcholine lipid (GA-PC Lip) and determine its susceptibility to tumor over-expressed secretory phospholipase A2 (sPLA2) and its anti-cancer effect compared to conventional liposomes (Convention Lip). The liposomes were characterized for size, drug loading, encapsulation efficiency, and stability. A 6-CF release assay was conducted to assess the sensitivity of the liposomes to the tumor-overexpressed secretory phospholipase A2 (sPLA2). In vitro experiment, the sPLA2 levels in the Colo205 cell culture medium were detected by the Elisa kit and the anti-cancer effect of the oxaliplatin (L-OHP) loaded GA-PA Lip was analyzed by the CCK-8 assay. Results showed that both of L-OHP loaded formulations (GA-PC Lip and Convention Lip) had similar particle sizes of ∼100 nm and close entrapment efficiency values of 4.5-4.8%. The results of CF release assay indicated that the labeled GA-PC Lip had released more quickly than CF labeled Convention Lip in the presence of Bv sPLA2 and GA-PC Lip had a release of about 95% 6-CF at 2 h, whereas Convention Lip only released about 13% 6-CF. In addition, the average concentrations of sPLA2 in the cell-conditioned medium (CCM) of Colo205 cancer cells increased with incubation time and L-OHP loaded GA-PC Lip had much greater anti-proliferative activity than Convention Lip against Colo205 cells. These findings suggest that GA-PC Lip is an ideal complex for sPLA2-triggered release and has potential applications in enzyme-triggered smart anti-cancer drug release system to increase the anti-cancer effect.