IL-24 engineered mesenchymal stem cells as a novel therapeutic strategy to remodel the tumor microenvironment in non-small cell lung cancer

Immune checkpoint inhibitor (ICI) resistance in non-small cell lung cancer (NSCLC) is frequently driven by an immunosuppressive tumor microenvironment (TME). To address this issue, we developed IL-24-iMSC, a novel mesenchymal stem cell-based therapy designed to remodel the immunosuppressive tumor microenvironment through sustained secretion of interleukin 24 (IL-24), an immunomodulatory cytokine with anti-cancer properties. Induced mesenchymal stem cells (iMSCs) were derived from induced pluripotent stem cells (iPSCs) and the IL-24 gene was integrated into iMSC at the B2M locus under the control of the EF1alpha promoter using CRISPR/Cas. IL-24-iMSCs were confirmed to constitutively secrete IL-24. Metastatic lung cancer models were established by tail vein injection of Lewis Lung Carcinoma cells expressing luciferase (LLC-luc) into immunocompetent C57BL/6 mice. Tumor progression was monitored using an In Vivo Imaging System (IVIS). Treatment was administered 20 days after tumor inoculation, and mice were randomized into three groups: iMSC, IL-24-iMSC, or vehicle control. All mice were sacrificed three days after treatment. Tumor growth was confirmed by bioluminescence imaging using IVIS, and tumor samples were collected for immune profiling. While there was no significant difference in tumor growth among the three groups, tumors exposed to IL-24-iMSC demonstrated a pro-inflammatory phenotype. Multiplex immunohistochemistry confirmed infiltration of MSCs into the TME, with significantly increased IL-24 expression in the IL-24-iMSC arm. Compared with the control group (untreated), tumors treated with IL-24-iMSC showed increased CD8+ T cells, dendritic cells, and memory CD4+ T cells. IFN-gamma and TNF-alpha expressions were also elevated in the IL-24-iMSC treatment arm. On the contrary, regulatory T cells and exhausted T cells (PD1+ TIM3+) were significantly reduced in the IL-24-iMSC group. In conclusion, IL-24-iMSCs demonstrated the ability to modulate immune cell composition within the tumor microenvironment, suggesting their potential to synergize with ICI in NSCLC.