Anti-HER2 scFv-Directed Extracellular Vesicle-Mediated mRNA-Based Gene Delivery Inhibits Growth of HER2-Positive Human Breast Tumor Xenografts by Prodrug Activation

Abstract

This paper deals with specific targeting of the prodrug/enzyme regimen, CNOB/HChrR6, to treat a serious disease, namely HER2 human breast cancer with minimal off-target toxicity. HChrR6 is an improved bacterial enzyme that converts CNOB into the cytotoxic drug MCHB. Extracellular vesicles (EV) were used for mRNA-based H gene delivery: EVs may cause minimal immune rejection, and mRNA may be superior to DNA for gene delivery. To confine HChrR6 generation and CNOB activation to the cancer, the EVHB chimeric protein was constructed. It contains high-affinity anti-HER2 scFv antibody (ML39) and is capable of latching on to EV surface. Cells transfected with EVHB-encoding plasmid generated EVs displaying this protein ("directed EVs"). Transfection of a separate batch of cells with the new plasmid, XPort/HChrR6, generated EVs containing HChrR6 mRNA; incubation with pure EVHB enabled these to target the HER2 receptor, generating "EXO-DEPT" EVs. EXO-DEPT treatment specifically enabled HER2-overexpressing BT474 cells to convert CNOB into MCHB in actinomycin D-independent manner, showing successful and specific delivery of HChrR6 mRNA. EXO-DEPTs-but not undirected EVs-plus CNOB caused near-complete growth arrest of orthotopic BT474 xenografts , demonstrating for the first time EV-mediated delivery of functional exogenous mRNA to tumors. EXO-DEPTs may be generated from patients' own dendritic cells to evade immune rejection, and without plasmids and their potentially harmful genetic material, raising the prospect of clinical use of this regimen. This approach can be used to treat any disease overexpressing a specific marker..

Decreased miR- 31 Suppress Cell Migration and Proliferation By Targeting Syncytin-1 in Pancreatic Carcinoma

“…MiRNAs are a kind of noncoding RNAs, which have been proved to play a role in the post-transcriptional level by targeting the 3'-untranslated region (3'-UTR) of the downstream gene [39][40][41][42][43]. We use variety of online tools to predict the potential RNAs for syncytin-1, including DIANA, TargetScan, and PITA.…”

Upregulation of syncytin-1 promotes invasion and metastasis by activating epithelial-mesenchymal transition-related pathway in endometrial carcinoma

“…These findings suggest that syncytin-1 may be a regulatory gene for EC. EMT is an effective way for epithelial cells to acquire migratory capacity [41][42][43][44][45][46][47][48] and has become an important pathway for invasion and metastasis of epithelial cell carcinoma. Various studies showed that the development of EMT is accompanied with changes in markers, including E-cadherin, N-cadherin, and vimentin.…”

Mesenchymal Stem Cell-Derived Extracellular Vesicles: Challenges in Clinical Applications

“…It is speculated that MSC-EV express chemokine receptors that facilitate targeting to injured regions (Kim et al, 2012;Moon et al, 2019). Decoration of the EV surface with phosphatidylserine-binding and HER2-targeting proteins has been shown to increase EV delivery to HER2-expressing cells (Wang et al, 2018). Other studies demonstrate the feasibility of this decorating method of targeting EV to specific tissues (Alvarez-Erviti et al, 2011;Kooijmans et al, 2016;Antes et al, 2018), so perhaps these strategies may be applied to MSC-EV as well.…”