biostudies-literatureVahabi MFondazione AIRC per la ricerca sul cancro ETS217https://www.ebi.ac.uk/biostudies/studies/S-EPMC12288264biostudies-literatureUnknown44(1)<h4>Background</h4>Nucleoside analogues are crucial in treating non-small cell lung cancer (NSCLC), but resistance hampers patient outcomes. The cytidine analogue RX-3117 shows promise in gemcitabine-resistant cancers, yet mechanisms underlying acquired resistance to this drug remain unexplored. This study includes a comprehensive investigation into RX-3117 resistance mechanisms by leveraging new preclinical models and cutting-edge genomic tools, including a CRISPR-Cas9 knockout screen and transcriptomics.<h4>Methods</h4>NSCLC cell lines A549 and SW1573 were exposed to stepwise increasing concentrations of RX-3117 to establish stable resistant subclones, confirmed by SRB and clonogenic assays. Intracellular RX-3117 nucleotide levels were measured via LC/MS-MS, prompting the evaluation and Journal of experimental & clinical cancer research : CRUnraveling resistance mechanisms to the novel nucleoside analog RX-3117 in lung cancer: insights into DNA repair, cell cycle dysregulation and targeting PKMYT1 for improved therapy.PMC12288264IG 24444Lencioni GStrano SWang BVahabi MGiovannetti EBlandino GSarkisjan DDonati VXu GHassouni BEHoneywell RJDeng DMantini GPeters GJfalseUnraveling resistance mechanisms to the novel nucleoside analog RX-3117 in lung cancer: insights into DNA repair, cell cycle dysregulation and targeting PKMYT1 for improved therapy.<h4>Background</h4>Nucleoside analogues are crucial in treating non-small cell lung cancer (NSCLC), but resistance hampers patient outcomes. The cytidine analogue RX-3117 shows promise in gemcitabine-resistant cancers, yet mechanisms underlying acquired resistance to this drug remain unexplored. This study includes a comprehensive investigation into RX-3117 resistance mechanisms by leveraging new preclinical models and cutting-edge genomic tools, including a CRISPR-Cas9 knockout screen and transcriptomics.<h4>Methods</h4>NSCLC cell lines A549 and SW1573 were exposed to stepwise increasing concentrations of RX-3117 to establish stable resistant subclones, confirmed by SRB and clonogenic assays. Intracellular RX-3117 nucleotide levels were measured via LC/MS-MS, prompting the evaluation and 2025-01-01T00:00:00Z2025 Jul2026-03-10T23:05:55.735Z2025-08-12T03:05:01.635ZS-EPMC122882644070255210.1186/s13046-025-03470-z