Non-Small Cell Lung Cancer (NSCLC) is the leading cause of cancer death worldwide. Although immune checkpoint inhibitors (ICIs) have shown remarkable clinical efficacy,they can also induce a paradoxical cancer acceleration,known as hyperprogressive disease (HPD),whose causative mechanisms are still unclear. This study investigated the mechanisms of ICI resistance in an HPD-NSCLC model. Two primary cell cultures were established from samples of a NSCLC patient,before ICI initiation (“baseline”,NSCLC-B) and during HPD (“hyperprogression”,NSCLC-H). The cell lines were phenotypically and molecularly characterized through immunofluorescence,Western Blotting and RNA-Seq analysis. To assess cell plasticity and aggressiveness,cellular growth patterns were evaluated both in vitro and in vivo through 2D and 3D cell growth assays and patient-derived xenografts establishment. In vitro investigations,including the evaluation of cell sensitivity to interferon-gamma (IFN-γ) and cell response to PD-L1 modulation,were conducted to explore the influence of these factors on cell plasticity regulation. NSCLC-H exhibited increased expression of specific CD44 isoforms and a more aggressive phenotype,including organoid formation ability,compared to NSCLC-B. Plastic changes in NSCLC-H were well described by a deep transcriptome shift,that also affected IFN-γ–related genes,including PD-L1. IFN-γ–mediated cell growth inhibition was compromised in both 2D-cultured NSCLC-B and NSCLC-H cells. Further,the cytokine induced a partial activation of both type I and type II IFN-pathway mediators,together with a striking increase in NSCLC-B growth in 3D cell culture systems. Finally,low IFN-γ doses and PD-L1 modulation both promoted plastic changes in NSCLC-B,increasing CD44 expression and its ability to produce spheres. Our findings identified plasticity as a relevant hallmark of ICI-mediated HPD by demonstrating that ICIs can modulate the IFN-γ and PD-L1 pathways,driving tumor cell plasticity and fueling HPD development. The online version contains supplementary material available at 10.1186/s12967-024-06023-8.
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