Abstract 1367: Dual remodeling of RCC-associated fibroblasts via miR-196b antagomir and COUP-TFII inhibitor ultrasmall lactoferrin-lipid nano-assemblies augments immunotherapy.

Abstract Renal cell carcinoma (RCC), a type of kidney cancer, is among the 10 most common cancers in both men and women. Despite the advanced progress of cancer immunotherapy, many RCC patients show resistance to immune checkpoint inhibitors. Cancer-associated fibroblasts (CAFs) play a key role in promoting immunosuppression in RCC, which markedly impairs the antitumor immune response. Several oncogenic miRNAs (OncomiRs) are upregulated in RCC fibroblasts where they drive their differentiation into CAFs by modulating the expression of target genes involved in phenotypic changes associated with CAFs. Moreover, COUP-TFII is an unexplored transcription factor implicated in the differentiation of kidney fibroblasts. In our study, microarray-based miRNA sequencing analysis showed upregulation of some miRNAs (e.g., miR 196b) in RCC patient-derived CAFs compared to normal kidney fibroblasts. Therefore, we engineered novel ultrasmall recombinant lactoferrin (LF)-stabilized lipid nano-assemblies (NAs) co-loaded with antagomir (anti-miR 196b) and COUP-TFII inhibitor (CIA-1) to induce synergistic remodeling of renal CAFs into a quiescent phenotype. LF, a GRAS (Generally Regarded as Safe) glycoprotein, targets tumor fibroblasts through natural tropism to LRP1 and intelectin-1 receptors, over-expressed in fibrotic tissues. In addition, the recombinant form of human lactoferrin (rhLF) has high batch-to-batch consistency, reduced immunogenicity, precise molecular tailoring for drug incorporation and surface modification, and well-tolerated following systemic administration. The rhLF-lipid NAs exhibited ultrasmall and uniform size (5-7 nm) with discoidal morphology. Moreover, the NAs were successfully internalized into RCC patient-derived CAFs without inducing remarkable toxicity. The NAs reprogrammed renal CAFs into quiescence as evidenced by downregulation of fibroblast activation (e.g., αSMA, FAP, and S100A4) and extracellular matrix (e.g., Col1α1, Col3α1, fibronectin, periostin, and tenascin C) markers as well as upregulation of the quiescence marker p27. In addition, the secretion of IL-6, IL-8 and MCP1 by renal CAFs was significantly reduced after treatment with the NAs. Further treatment of renal cancer cells with conditioned media of CAFs pre-treated with the engineered NAs resulted in reduced migration and downregulation of stemness, epithelial to mesenchymal transition and proliferation markers. In vivo, the ultrasmall size and LF-targeting properties promoted higher accumulation of the IRDye 800CW-coupled fluorescent NAs in kidney tumors relative to liver and spleen following i.v. injection into orthotopic syngeneic kidney tumor-bearing mice. Our strategy represents a paradigm shift in RCC treatment, as it addresses the immunosuppressive role of CAFs by dual mechanistic nano-engineering approach. Citation Format: Ahmad Ziada, Leyla Escalante Gonzalez, Zara Sideeka, Aya Jarrous, Anna Mayer, Leo Ren, Ashley Park, Amrendra Ajay, Cuiyan Xin, Ahmed Elzoghby. Dual remodeling of RCC-associated fibroblasts via miR-196b antagomir and COUP-TFII inhibitor ultrasmall lactoferrin-lipid nano-assemblies augments immunotherapy abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 1367.