Lipid Nanoparticle Mediated Delivery of Docetaxel Prodrug for Exploiting Full Potential of Gold Radiosensitizers in the Treatment of Pancreatic Cancer.

Background: Pancreatic cancer is one of the leading causes of cancer deaths worldwide. Current chemoradiation therapy suffers from normal tissue toxicity. To overcome this problem, we are proposing incorporating nanoparticles as radiosensitizers and as drug delivery vehicles into current chemoradiation regimes. Gold nanoparticles (GNPs) and Docetaxel (DTX) have shown very promising synergetic radiosensitization effects despite DTX toxicity to normal tissues. Here, we explored the effect of DTX prodrug encapsulated in lipid nanoparticles (LNP DTX−P ) on GNP uptake in pancreatic cancer models in vitro and in vivo . Methods For the in vitro experiment, pancreatic cancer cell line, MIA PaCa-2, were cultured and dosed with 7.5 µg/mL of GNPs (of ~ 11 nm in diameter functionalized with PEG and RGD peptide) and with 45 nM of free DTX or equivalent dose of LNP DTX−P . For the in vivo experiment, MIA PaCa-2 were implanted subcutaneously in NRG mice and the mice were dosed with 2 mg/kg of GNPs and 6 mg/kg of DTX or equivalent dose of LNP DTX−P . GNPs content in mice and in cells were measured using Inductively Coupled Plasma–Mass Spectrometry (ICP–MS). Results The results show that LNP DTX−P treated tumour samples have no less than 191% increase in GNPs uptake compared to control samples in both in vitro and in vivo . The results also show that LNP DTX−P treated tumour samples have retained over 160% of GNPs compared to control samples in both in vitro and in vivo . No significant difference was found in GNP uptake or retention between free DTX and LNP DTX−P in tumour treated samples in vivo . Conclusions The results are very promising as LNP DTX−P have superior targeting of tumour tissues compared to free DTX due to their nano size and their ability to be functionalized. Because of their minimal toxicity to normal tissues, both GNPs and LNP DTX−P can be ideal radiosensitization candidates in radiotherapy and would produce very promising synergistic therapeutic outcome. Current radiotherapy treatments can hugely benefit from the effects of these two radiosensitizers boosting the radiation dose to the tumour while reducing the normal tissue dose. This in return will improve patient outcome and quality of life.