Gossypin suppresses mutant KRAS G12D driven oncogenic and adipogenic activity via NF-κB signaling in pancreatic cancer.

Pancreatic cancer is an aggressive malignancy driven largely by mutant KRAS and constitutively active downstream NF-κB pathway. Molecular docking of phenolic bioflavonoids identified a few lead compounds targeting KRAS G12D mutant protein. Gossypin exhibited better molecular docking, where MD simulation depicted a stable energetically favorable gossypin-KRAS complex, compared to other molecules. Isothermal titration calorimetry analysis confirmed the existence of thermodynamically favorable interaction between KRAS G12D and the ligand gossypin. Influence of gossypin on pancreatic cancer was not explored till date. This study aimed to address the role of KRAS downstream target NF-κB in mediating anti-oncogenic and lipid metabolic effects of gossypin in pancreatic cancer. Gossypin treatment significantly inhibited cell proliferation, migration, invasion, and stemness potential in pancreatic PANC-1 and MIA PaCa-2 cancer cells. This lead molecule blocked PI3K/AKT/mTOR and ERK signaling with concomitant inhibition of NF-κB activity. P65 (a subunit of NF-κB) overexpression was found to efficiently rescue the inhibitory effect of gossypin on oncogenic and adipogenic activities, including lipid accumulation, cholesterol and triacylglyceride contents in PANC-1 cells. This suppressed adipogenic potential was accompanied by downregulation of lipid regulatory genes (e.g., SREBF1, HMGCoR, and Perilipin-1) upon gossypin treatment. SREBF1 transcription was directly regulated by NF-κB as evidenced in ChIP assay. Moreover, down-regulated adipogenic potential-mediated by knocking down of SREBF1 gene was retained upon forced expression of p65, suggesting that NF-κB-stimulated lipogenic activity is dependent on SREBP1. These findings, for the first time, unravel KRAS/NF-κB/SREBP1 signaling as a central mediator for gossypin-inhibited lipid metabolic activity and subsequent oncogenic potential in pancreatic cancer.