LC-2

The role of KRAS mutation in non‐small cell lung cancer (NSCLC) initiation and progression is well‐established. However, “undruggable” KRAS protein poses the research of small molecule inhibitors a significant challenge. Addressing this, proteolysis‐targeting chimeras (PROTACs) have become a cutting‐edge treatment method, emphasizing protein degradation. A modified ethanol injection method was employed in this study to formulate liposomes encapsulating PROTAC drug LC‐2 (LC‐2 LPs). Precise surface modifications using cell‐penetrating peptide R8 yielded R8‐LC‐2 liposomes (R8‐LC‐2 LPs). Comprehensive cellular uptake and cytotoxicity studies unveiled that R8‐LC‐2 LPs depended on concentration and time, showcasing the superior performance of R8‐LC‐2 LPs compared to normal liposomes. In vivo pharmacokinetic profiles demonstrated the capacity of DSPE‐PEG2000 to prolong the circulation time of LC‐2, leading to higher plasma concentrations compared to free LC‐2. In vivo antitumor efficacy research underscored the remarkable ability of R8‐LC‐2 LPs to effectively suppress tumor growth. This study contributed to the exploration of enhanced therapeutic strategies for NSCLC, specifically focusing on the development of liposomal PROTACs targeting the “undruggable” KRAS protein. The findings provide valuable insights into the potential of this innovative approach, offering prospects for improved drug delivery and heightened antitumor efficacy.

LC‐2, is a molecule of proteolysis targeting chimeras (PROTACs), with a large molecular weight, poor water solubility and low system bioavailability, which was designed to degrade KRASG12C protein. In this study, LC‐2 PEGylated liposomes were developed and characterized. Moreover, a rapid and sensitive liquid chromatography–tandem mass spectrometry (LC–MS/MS) method in rat plasma was established and effectively utilized for an in vivo pharmacokinetic investigation. LC‐2 PEGylated liposomes with better properties were prepared by an improved ethanol injection method. The chromatographic separation was achieved on an Agilent Eclipse XDB‐CN column (100 × 2.1 mm, 3.5 μm) with acetonitrile–ammonium deionized water (5 mm; 80:20, v/v) at a flow rate of 0.5 ml/min. The mass spectra of LC‐2 and the IS (gefitinib) were obtained at m/z 1132.5 → 626.4 and 447.1 → 128.2, respectively. The pharmacokinetic study was carried out by analyzing plasma concentrations of LC‐2 solution or produced LC‐2 PEGylated liposomes in rats using the developed and validated method. The pharmacokinetic results indicate that PEGylated liposome‐encapsulation protected LC‐2 from the influence of endogenous protein binding, improved insolubility, prolonged half‐life and increased system bioavailability. This study provides a feasible solution for future preclinical and clinical studies of LC‐2 and/or other PROTACs.