Abstract:
Diabetes and the resulting hyperglycemia are metabolic complications frequently linked to pancreatic cancer (PC). In this study, we observe that the long non-coding RNA (lncRNA)-YIYA, which resides in a genomic region (1q32), frequently altered in various cancers, is overexpressed under conditions of chronic or intermittent high glucose (HG; 25 mM) compared to normal glucose (NG; 5.5 mM) in pancreatic ductal adenocarcinoma (PDAC) cells. It plays a pivotal role in regulating cellular metabolism-linked proliferation of PDAC cells, both under 2D and 3D conditions. Analysis of clinical datasets suggested that patients with elevated YIYA expression generally experience reduced survival in pancreatic cancer. Mechanistically, YIYA was found to regulate cellular energy metabolism and promote a Warburg phenotype, thereby facilitating the rapid proliferative status of PDAC cells. YIYA-mediated effects were found to be dependent on KRAS. Interestingly, the RIP assay revealed that YIYA interacts not only with KRAS but also with an important enzyme catalyzing the final step of the biochemical process, glycolysis, pyruvate kinase M2 (PKM2). YIYA was found to be predominantly localised in the cytoplasm, protecting the stability of the KRAS protein under a hyperglycaemic state. Importantly, YIYA knockdown enhanced autophagy-mediated degradation of KRAS. Our study is the first to identify YIYA as a glucose-responsive lncRNA in PDAC cells, and to reveal a novel YIYA-mediated connection between oncogenic KRAS signalling and metabolic reprogramming. Targeting YIYA represents a promising therapeutic strategy by disrupting the KRAS–PKM2–Warburg axis, thereby sensitizing PDAC cells.