Enhancing PD-1 Gene Silence in T Lymphocytes by Comparing the Delivery Performance of Two Inorganic Nanoparticle Platforms.

Suitable carriers are crucial to RNAi applications for cancer genotherapy and T-cell immunotherapy. In this research, we selected two extensively-investigated biocompatible inorganic nanoparticle carriers, i.e., layered double hydroxide (LDH) and lipid-coated calcium phosphate (LCP) and then compared their efficacy for siRNA delivery in T cells, in order to understand which carrier is more efficient in delivering functional programmed cell death protein 1 siRNA (PD-1 siRNA) to suspended T lymphocytes. Both LDH and LCP nanoparticles quickly delivered gene segment to mouse T cell lines (EL4), while the LCP nanoparticles exhibited more cellular uptake and higher PD-1 gene silence efficiency. We further demonstrated that LCP nanoparticles successfully reduced the expression of PD-1 in human ex vivo tumor infiltrating lymphocytes (TILs). Thus, LCP nanoparticles can be used as a better nano-carrier for gene therapy in lymphocytes, especially in regards to TIL-related cancer immunotherapy.