Novel nano-drug combination therapeutic regimen demonstrates significant efficacy in the transgenic mouse model of pancreatic ductal adenocarcinoma

The current work studied the chemopreventive efficacy of orally administered chitosan coated solid-lipid nanoparticle (c-SLN) encapsulated aspirin (ASP), curcumin (CUR) and free sulforaphane (SFN), ACS-cSLN, in the LSL-Kras ^G12D/+; Pdx-1 ^Cre/+ transgenic mouse model of pancreatic ductal adenocarcinoma (PDAC). In vitro uptake study and intracellular localization of ODA-FITC labeled ASP and CUR c-SLNs were performed in Panc-1 and MIA PaCa-2 cells by fluorescence microscopy. LSL-Kras ^G12D/+; Pdx-1 ^Cre/+ transgenic mice (n = 30) were randomly divided into 5 groups. Treatment groups were orally gavaged with ACS c-SLNs in three doses: low (2 + 4.5 + 0.16 mg/kg), medium (20 + 45 + 1.6 mg/kg) and high (60 + 135 + 4.8 mg/kg), respectively. After 20 weeks of treatment, mice pancreas were harvested, stained with dye and scored according to various pancreatic intraepithelial neoplasms (PanIN) categories by an independent observer. In vitro, cellular uptake evaluated on Panc-1 and MIA PaCa-2 cells resulted in higher fluorescence intensities, indicating increased cellular uptake of ASP and CUR c-SLNs. For further evidence, the addition of lysoID (red fluorescence) demonstrated location and uptake of ASP and CUR c-SLNs into the lysosome. In vivo, treatment with ACS c-SLN for 20-weeks did not cause obvious adverse effects on growth and no statistically significant differences in body weight were observed between groups. However, the weight (mean ± SEM) of pancreas at the end of the study was higher in blank c-SLN group (223.6 ± 42.2 mg) compared to low (138.0 ± 26.0 mg; not significant [NS]), medium (145.0 ± 9.0 mg; NS), and high (133.8 ± 20.3 mg; NS) ACS c-SLN treated groups, demonstrating the efficacy of ACS c-SLN nanoformulations. The low, medium and high dose of ACS c-SLN combinations exhibited a reduction in tumor incidence (PanIN count) by 16.6% (P < 0.01), 66.8% (P < 0.01), and 83.4% (P < 0.01), respectively. These studies provide further proof for the use of an oral, low dose nanotechnology-based combinatorial regimen for the chemoprevention of PDAC.