Photoactivation of sulfonated polyplexes enables localized gene silencing by DsiRNA in breast cancer cells

Nanomedicine. 2020 Jun;26:102176. doi: 10.1016/j.nano.2020.102176. Epub 2020 Mar 6.


Translation potential of RNA interference nanotherapeutics remains challenging due to in vivo off-target effects and poor endosomal escape. Here, we developed novel polyplexes for controlled intracellular delivery of dicer substrate siRNA, using a light activation approach. Sulfonated polyethylenimines covalently linked to pyropheophorbide-α for photoactivation and bearing modified amines (sulfo-pyro-PEI) for regulated endosomal escape were investigated. Gene knock-down by the polymer-complexed DsiRNA duplexes (siRNA-NPs) was monitored in breast cancer cells. Surprisingly, sulfo-pyro-PEI/siRNA-NPs failed to downregulate the PLK1 or eGFP proteins. However, photoactivation of these cell associated-polyplexes with a 661-nm laser clearly restored knock-down of both proteins. In contrast, protein down-regulation by non-sulfonated pyro-PEI/siRNA-NPs occurred without any laser treatments, indicating cytoplasmic disposition of DsiRNA followed a common intracellular release mechanism. Therefore, sulfonated pyro-PEI holds potential as a unique trap and release light-controlled delivery platform for on-demand gene silencing bearing minimal off target effects.

Keywords: Endosomal escape; Photosensitizer; Polymer; RNA interference; siRNA delivery.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Breast Neoplasms / genetics*
  • Breast Neoplasms / pathology
  • Breast Neoplasms / therapy
  • Cell Cycle Proteins / genetics*
  • Cell Line, Tumor
  • DEAD-box RNA Helicases / genetics*
  • Endosomes / drug effects
  • Female
  • Gene Knockdown Techniques
  • Gene Silencing*
  • Green Fluorescent Proteins / genetics
  • Humans
  • Polyethyleneimine / chemistry
  • Polyethyleneimine / pharmacology
  • Polymers / chemistry
  • Protein-Serine-Threonine Kinases / genetics*
  • Proto-Oncogene Proteins / genetics*
  • RNA Interference
  • RNA, Small Interfering / pharmacology
  • Ribonuclease III / genetics*


  • Cell Cycle Proteins
  • Polymers
  • Proto-Oncogene Proteins
  • RNA, Small Interfering
  • enhanced green fluorescent protein
  • Green Fluorescent Proteins
  • Polyethyleneimine
  • Protein-Serine-Threonine Kinases
  • polo-like kinase 1
  • DICER1 protein, human
  • Ribonuclease III
  • DEAD-box RNA Helicases