Anti-CTLA4 Peptide-Gemcitabine Nanoparticles Induce Lung Tumor Regression and Activate CD8 T-cells in Mice

Lung cancer remains a leading cause of global cancer mortality, primarily due to extensive tumor heterogeneity, inherent drug resistance, and the limited efficacy of conventional therapies. Current treatments often face challenges in achieving targeted delivery, leading to systemic toxicity and suboptimal therapeutic outcomes. The CTLA4 immune checkpoint pathway is a critical target in cancer immunotherapy, while gemcitabine is a widely used chemotherapeutic. This study addresses the need for enhanced, targeted delivery systems that combine chemotherapy with immunotherapy to overcome these limitations and improve patient prognosis.

Researchers designed and synthesized anti-CTLA4 peptide-conjugated gemcitabine prodrug nanoparticles (PD-NPs). The ARHPSWYRPFEGCG peptide, a cathepsin B cleavable FRRG linker, and gemcitabine were conjugated via a single-step amide bond, forming stable self-assembling PD-NPs. In vitro, A549 and NCI-H460 cell lines were used for cell viability, clonogenic, scratch, and flow cytometry apoptosis assays. In vivo, toxicity and biodistribution studies determined therapeutic doses. Subsequently, chemoimmunotherapeutic efficacy of PD-NPs was evaluated in a B16-F10 induced lung tumor mice model.

The synthesized PD-NPs exhibited a zeta potential of ±34.4 mV, an average particle size of 229.8 ± 2.1 nm, and a polydispersity index of 0.2, indicating a stable and monodisperse formulation. In vitro, PD-NPs demonstrated potent cytotoxic effects, suppressed clonogenicity, inhibited cellular migration, induced apoptosis, and inhibited carcinogenic protein expression in lung cancer cell lines. In vivo, treatment with PD-NPs resulted in significant tumor regression within the B16-F10 induced lung tumor mice model. This therapeutic effect was accompanied by restoration of lung tissue architecture, activating CD8 expression, and altering TNF-α expression. These findings collectively highlight the dual therapeutic potential.

In vivo treatment with anti-CTLA4 peptide-gemcitabine nanoparticles led to significant tumor regression, restored lung tissue architecture, and activated CD8 expression.