Human ELANE mRNA

mRNA-based applications have achieved remarkable success in the development of next-generation vaccines and the treatment of a variety of liver diseases. Overcoming the challenges of delivering mRNA to extrahepatic tissues, especially to specific cells within tissues, is critical for precision therapy. Here, researchers developed a platform to selectively deliver mRNA to target cells within tissues by combining lipid nanoparticle (LNP)-based targeted delivery with mRNA sequence-controlled expression. The integration of unique microRNA target sites into the mRNA scaffold further enhanced the control of protein translation in specific cells within the target tissue. This combined strategy, named SELECT (Simplified LNP with Engineered mRNA for Cell-type Targeting), demonstrated its effectiveness in distinguishing mRNA expression in tumor cells from normal cells based on intracellular microRNA abundance. This SELECT encapsulates mRNA encoding the tumor-specific cytotoxic protein human ELANE, and exhibits selective mRNA delivery to tumor lesions and significant inhibition of tumor growth in a mouse melanoma lung metastasis model. Overall, SELECT has great potential as a new precision tumor treatment method, and also provides good prospects for other mRNA therapies targeting specific cell types.

Neutrophil elastase (ELANE) is a secreted serine protease expressed in neutrophils that selectively kills cancer cells while protecting adjacent non-cancerous cells. Here, researchers synthesized a series of ELANE-related mRNAs, including full-length human ELANE mRNA (hELANEFL) with a signal peptide (SP) at the N-terminus, human ELANE (hELANE) mRNA, mouse ELANE (mELANE) mRNA, and DD95 mRNA. After evaluating their toxicity to tumor cells, it was found that both hELANE and mELANE mRNAs showed superior tumor killing ability to that reported for DD95 mRNA in a dose-dependent manner (Figure 1A). hELANE mRNA was then used to treat a variety of cancer cells (including MDA-MB-231, B16F10, and LLC1) and non-cancerous cells (including 3T3 and L02) to verify its ability to selectively kill tumor cells (Figure 1A, B). The results showed that hELANE mRNA was able to effectively kill all tested cancer cells while having minimal toxicity to non-cancerous cells. This was further confirmed by the fluorescent images of Calcein-AM staining and the results of FACS apoptosis analysis (Figure 1C, D). Next, the researchers constructed the miR142ts-126ts hELANE mRNA sequence to verify whether the miRts modification could maintain its tumor-killing ability (Figure 1E). It is worth noting that compared with the WT hELANE mRNA group, the miR142ts-126ts hELANE mRNA group maintained a high level of cytotoxicity in various tumor cell lines (Figure 1F) and produced a positive signal for tumor suppression in vivo.

Figure 1. hELANE mRNAs selectively killed a wide range of cancer cells, with less toxicity to non-cancer cells. (Fei Y, et al., 2024)