Endo/Lysosomal-Escapable Lipid Nanoparticle Platforms for Enhancing mRNA Delivery in Cancer Therapy

Abstract

mRNA-based drug development is revolutionizing tumor therapies by enabling precise cancer immunotherapy, tumor suppressor gene restoration, and genome editing. However, the success of mRNA therapies hinges on efficient delivery systems that can protect mRNA from degradation and facilitate its release into the cytoplasm for translation. Despite the emergence of lipid nanoparticles (LNPs) as a clinically advanced platform for mRNA delivery, the efficiency of endo/lysosomal escape still represents a substantial bottleneck. Here, we summarize the intracellular fate of mRNA-loaded LNPs, focusing on their internalization pathways and processing within the endo-lysosomal system. We also discuss the impact of endo-lysosomal processes on mRNA delivery and explore potential strategies to improve mRNA escape from endo-lysosomal compartments. This review focuses on molecular engineering strategies to enhance LNP-mediated endo/lysosomal escape by optimizing lipid composition, including ionizable lipids, helper lipids, cholesterol, and PEGylated lipids. Additionally, ancillary enhancement strategies such as surface coating and shape management are discussed. By comprehensively integrating mechanistic insights into the journey of LNPs within the endo-lysosome system and recent advances in lipid chemistry, this review offers valuable inspiration for advancing mRNA-based cancer therapies by enabling robust protein expression.

Keywords: endo/lysosomal escape; gene therapy; lipid nanoparticle; mRNA delivery.

Figure 1

The basic bibliometric analysis of LNPs in mRNA delivery for cancer therapy. (A) The annual distributions of publications and their citations. Data were collected using the search query (TS = (Cancer OR Tumor OR Carcinoma) AND AB = (“mRNA” OR “Circular RNA”) AND AB = (Deliver*) NOT AB = (siRNA) AND TS = (“lipid nanoparticle*” OR “LNP” OR “liposome*”)) in Web of Science core collection from 2006 to 2025, and the histogram was created by using GraphPad Prism 9. (B) The main topics in this field analyzed by CiteSpace Version 6.3.R1. All keywords were extracted from the abstract of hit publications identified in A. Each circle represents a keyword, and its color matches the color of the cluster it belongs to (enlarged words are guided by #). Specifically, the two keywords related to endosomal/lysosomal escape, ‘intracellular delivery’ and ‘endosomal escape’, are highlighted with stars.

Figure 2

A typical intracellular journey of LNP-encapsulated mRNA in application. The mRNA-loaded LNP is introduced into early endosomes after being internalized through CME, from which some are recycled back to the extracellular space. A portion of the mRNA successfully escapes to the cytoplasm in the same period, achieving its expected translation. Meanwhile, another fraction of the LNPs progresses through maturation into late endosomes and eventually into lysosomes, where they are subjected to degradation.

Figure 3

Representative research of the endo/lysosomal-escapable LNPs for mRNA delivery. (A) For LNPs composed of DOPE-Cx, the interaction between PC in the endosomal membrane and DOPE-Cxs forms ionic pairs, which disrupts the stability of the lamellar phase of DSPC and facilitates a phase transition. Ultimately, this phase transition promotes the endosomal escape of the encapsulated mRNA. Copyright 2025 by Wiley. (B) Replacing 25% and 50% of cholesterol with 7α-hydroxycholesterol in LNPs results in a diminished number of recycling endosomes and an increased production of late endosomes. This compositional adjustment enhances the delivery of mRNA to primary human T cells in ex vivo experiments. Copyright 2022 by Elsevier. (C) Cryo-TEM observed distinct structural variations between normal LNPs and the incorporation of β-sitosterol into LNPs (eLNP), Scale = 100 nm. While monitoring the endosomal escape by smFISH, the authors obtained representative fluorescent images showing mRNA and LNPs and conducted image analysis after delivery with LNPs or eLNPs in HeLa cells, Scale = 10 μm. For higher clarity, please refer to the original publication. Copyright 2020 by Nature Publishing Group. (D) The schematic representation of the transfection mechanism by SA-modified LNPs indicates that the encapsulated mRNA is released into the cytoplasm upon its exit from the early endosomes, circumventing lysosomal degradation. Furthermore, mRNA within the early endosome may be diverted toward the Golgi apparatus and endoplasmic reticulum pathways. Copyright 2023 by Elsevier. (E) The acoustically responsive fusogenic LNP demonstrated enhanced delivery when the transfection occurred in the presence of acoustic shock waves. For higher clarity, please refer to the original publication. Copyright 2019 by ACS Publications.