Therapeutic efficacy of in-vivo IL-12 plasmid delivery using microbubble-assisted ultrasound in a B16F10 mouse melanoma model: A proof of concept

Abstract

International audienceIn-vivo targeted delivery of immunostimulatory molecules for melanoma treatment is a promising strategy to overcome complexity, toxicity, and cost associated with current immunotherapies. Among these molecules, interleukine-12 (IL-12) is a potent immunostimulatory cytokine that plays a major role in antitumoral immune response. However, systemic administration of IL-12 induces severe side effects, highlighting the need for efficient and safe in-vivo delivery modalities. Microbubble-assisted ultrasound (MB-assisted US) is an emerging non-invasive and targeted method for therapeutic molecule delivery. This study aimed to evaluate its efficacy for intratumoral (i.t.) delivery of a plasmid encoding IL-12 (pIL-12) in a mouse melanoma model. In-vitro, delivery of 5 or 10 g of pIL-12 into melanoma cell suspensions using MB-assisted US increased IL-12 concentration to 1429 ± 125 and 2352 ± 125 pg/mL, respectively, whereas pIL-12 treatment alone did not elicit IL-12 secretion. Similarly, acoustically mediated delivery of 10 or 50 g of pIL-12 into melanoma spheroids significantly increased IL-12 concentration - 131 ± 7 and 250 ± 60 pg/mL respectively - compared to pIL-12 alone (0 pg/mL for 10 g and 7.5 ± 7.5 pg/mL for 50 g). In-vivo, acoustically mediated pIL-12 delivery increased serum mIL-12 concentration by 5-fold compared with i.t. pIL-12 injection alone, promoting NK cell recruitment and activation within the tumor microenvironment. By day 15, this strategy reduced tumor volume by 2.5-fold relative to i.t. pIL-12 alone and improved mouse health status. These findings confirm that MB-assisted US is a relevant modality for in-vivo delivery of immunostimulatory molecules in melanoma therapy