Bifunctional Au-templated RNA nanoparticles enable direct cell uptake detection and GRP75 knockdown in prostate cancer

J Mater Chem B. 2020 Mar 11;8(10):2169-2176. doi: 10.1039/c9tb02438g.

Abstract

Nucleic acids templated on gold (Au) surfaces have led to a wide range of functional materials ranging from microarrays, sensors and probes in addition to drug delivery and treatment. In this application, we describe a simple and novel method for templating amino-functionalized RNA onto Au surfaces and their self-assembly into small, discrete nanoparticles. In our method, sample hybridization with a complementary RNA strand with and without a fatty acid (palmitamide) appendage produced functionalized double-stranded RNA on the Au surface. The resulting Au-functionalized RNA particles were found to be stable under reducing conditions according to UV-Vis spectroscopy. Sample characterization by DLS and TEM confirmed self-assembly into primarily small (∼10-40 nm) spherical shaped nanoparticles expected to be amenable to cell biology. However, fluorescence emission (λexc: 350 nm, λem: 650 nm) revealed radiative properties which limited cell uptake detection. Introduction of FITC within the Au-functionalized RNA particles produced a bifunctional probe, in which FITC fluorescence emission (λexc: 494 nm, λem: 522 nm) facilitated cell uptake detection, in a time-dependent manner. The dual encapsulation-release profiles of the FITC-labeled Au-functionalized RNA particles were validated by time-dependent UV-Vis spectroscopy and spectrofluorimetry. These experiments respectively indicated an increase in FITC absorption (λabs: 494 nm) and fluorescence emission (λem: 522 nm) with increased sample incubation times, under physiological conditions. The release of Au-functionalized siRNA particles in prostate cancer (PC-3) cells resulted in concomitant knockdown of GRP75, which led to detectable levels of cell death in the absence of a transfection vector. Thus, the formulation of stable, small and discrete Au-functionalized RNA nanoparticles may prove to be valuable bifunctional probes in the theranostic study of cancer cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / chemical synthesis
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology*
  • Cell Proliferation / drug effects
  • Cell Survival / drug effects
  • Drug Screening Assays, Antitumor
  • Gold / chemistry
  • Gold / pharmacology*
  • HSP70 Heat-Shock Proteins / antagonists & inhibitors*
  • HSP70 Heat-Shock Proteins / metabolism
  • Humans
  • Male
  • Mitochondrial Proteins / antagonists & inhibitors*
  • Mitochondrial Proteins / metabolism
  • Molecular Structure
  • Nanoparticles / chemistry*
  • PC-3 Cells
  • Particle Size
  • Prostatic Neoplasms / drug therapy*
  • Prostatic Neoplasms / metabolism
  • Prostatic Neoplasms / pathology
  • RNA, Small Interfering / chemical synthesis
  • RNA, Small Interfering / chemistry
  • RNA, Small Interfering / pharmacology*
  • Surface Properties
  • Theranostic Nanomedicine

Substances

  • Antineoplastic Agents
  • HSP70 Heat-Shock Proteins
  • HSPA9 protein, human
  • Mitochondrial Proteins
  • RNA, Small Interfering
  • Gold