Lentivirus-mediated RNA interference of HMGA1 promotes chemosensitivity to gemcitabine in pancreatic adenocarcinoma.

The high mobility group A1 (HMGA1) proteins are overexpressed in pancreatic cancers. They are architectural nuclear proteins, which regulate expression of multiple genes implicated in the malignant phenotype. In this study, we hypothesized that HMG A1 silencing will promote chemosensitivity in pancreatic adenocarcinoma. We studied highly malignant pancreatic adenocarcinoma cell lines (MiaPaCa2 and PANC1). Lentiviral short-hairpin RNA (shHMGA1) expression vectors targeting HMGA1 were used for generation of lentiviral particles. Stable transfectants were developed after lentiviral transduction. Nuclear expression of HMGA1 was assayed using Western blot analysis. Chemosensitivity to gemcitabine was determined by IC50 analysis. Caspase activity was quantitated using fluorometric caspase profiling. Apoptosis was assessed by flow cytometric analysis. Lentivirus-mediated RNA interference resulted in 90% silencing of HMGA1 expression in each of MiaPaCa2 and PANC1 cell lines. HMGA1 silencing enhanced chemosensitivity to gemcitabine with an approximately 50% reduction in IC50 in each cell line. Lentivirus-mediated HMGA1 silencing promoted the activation of caspases 3, 2, 9, and 8, on exposure to gemcitabine. HMGA1 silencing resulted in reduction in Akt kinase activity. Lentivirus-mediated RNA interference of HMGA1 promoted chemosensitivity to gemcitabine in pancreatic adenocarcinoma. HMGA1 may represent a novel therapeutic target in pancreatic cancer.