Background:
Pancreatic ductal adenocarcinoma (PDAC) has a poor five-year survival rate (~10%) despite advances in chemotherapy and development of novel targeted therapies (i.e. KRAS inhibitors) (1-3). Therapeutic resistance is an insurmountable challenge, largely due to the immunosuppressive tumor microenvironment (TME), characterized by a dense fibrotic stroma rich in cancer-associated fibroblasts (CAFs), tumor-associated macrophages (TAMs), and extracellular matrix (ECM). However, targeting the TME in PDAC has been challenging, with dynamic metabolic crosstalk between cancer and stromal cells enabling rapid adaptation and immune evasion (4-5). Thus, novel approaches to treating PDAC need to consider the metabolic interactions within the TME and how these can be exploited to enhance the efficiency of current and emerging treatments.
Method:
Traditional 2D cell culture models lack physiological relevance and fail to mimic tumour complexity, limiting their translational accuracy. To address this, we developed a 3D spheroid model composed of PDAC cells and pancreatic stellate cells (PSCs), cultured in physiologically relevant Human Plasma-Like media. Using this model, we assessed the efficacy of novel NAMPT inhibitor OT-82, KRAS G12D inhibitor MRTX1133 and TP53 reactivator APR-246. These agents were compared to current PDAC chemotherapy, gemcitabine, and their combination potential assessed. Spheroid growth was monitored using Incucyte live imaging, and cytotoxicity was assessed with the CellTiter-Glo assay.
Results/Discussion:
Preliminary data using PDAC-PSC co-culture spheroids show that OT-82, MRTX1133, APR-246 and Gemcitabine showed highly significant cytotoxicity compared to vehicle control alone, with the strongest cytotoxic effects observed in combinations involving MRTX1133 and OT82. Although gemcitabine demonstrated greater efficacy than APR246, its potency was lower than that of MRTX1133 or OT82, suggesting that these agents may exert a stronger synergistic effect by targeting key survival pathways in PDAC cells. These pathways include KRAS-driven MAPK and PI3K/AKT signaling (targeted by MRTX1133) and NAMPT-mediated NAD⁺ biosynthesis (inhibited by OT82), both critical for tumor growth, metabolic adaptation, and immune evasion.
Summary
While KRAS and TP53 mutations are well-established oncogenic drivers, their combined impact with metabolic drugs like OT-82 on TME remodeling and immunosuppression remains underexplored. Targeting NAMPT-dependent metabolism, KRASG12D signaling, and TP53 dysfunction with gemiitabine concurrently may disrupt key tumor-stromal interactions and enhance immune infiltration.