Homo sapiens Raw sequence reads

Background & AimsPancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy characterized by significant heterogeneity among patients. The absence of specific symptoms and effective early screening tools frequently leads to delayed diagnosis and poor prognosis. The development and progression of PDAC are well divided into distinct phases, with pancreatic intraepithelial neoplasia (PanIN) often serving as a precursor to the more malignant PDAC stage. However, the molecular alterations in PanIN lesions and their contribution to tumor progression remain poorly defined. This study aims to elucidate the molecular mechanisms driving the initiation and progression of PDAC by conducting proteomic analyses on PanIN tissues from PDAC patients.MethodsWe employed laser capture microdissection-based proteomics to analyze protein expression changes in PanIN tissues and identified the transcriptional factor SP1 as a key player. To investigate the role of SP1 in PDAC initiation and progression, we generated a novel transgenic mouse model (KrasLSL-G12D/+; Trp53LSL-R172H/+; Sp1LOXP/LOXP; Pdx1-Cre). We carried out Seahorse assays and isotope tracing experiments to analyze the effect of SP1 on glycolysis. We further used shRNA-mediated knockdown and ChIP-seq assays to dissect the molecular mechanisms by which SP1 regulates glycolysis in PDAC tumorigenesis and progression. Finally, we evaluate the therapeutic potential of targeting SP1 and the glycolytic enzyme PFKFB4 using patient-derived organoid xenograft models (PDOXs).ResultsMetabolic reprogramming and SP1 upregulation occurred as early as the PanIN stage and persisted into the PDAC stage. SP1 overexpression promoted the proliferation of PDAC cells in vitro and tumor growth in PDOX models in vivo. Genetic ablation of Sp1 in spontaneous PDAC mouse models significantly inhibited tumorigenesis and progression. Mechanistically, SP1 was found to enhance aerobic glycolysis through transcriptional activation of PFKFB4, a critical regulator of PFK-1. Combination therapy targeting SP1 and PFKFB4 demonstrated significant efficacy against PDOXs in vivo.ConclusionsSP1 is a critical regulator of PDAC initiation and progression that is activated at the PanIN stage of tumorigenesis. By driving metabolic reprogramming through transcriptional control of PFKFB4, SP1 represents a critical vulnerability in PDAC. Targeting SP1 and its downstream effector PFKFB4 offers promising therapeutic potential for PDAC treatment.