RNA interference molecules have tremendous potential for cancer therapy but are limited by insufficient potency after i.v. administration. We previously found that Chol-DsiRNA polyplexes formed between cholesterol-modified dicer-substrate siRNA (Chol-DsiRNA) and the cationic diblock copolymer PLL[30]-PEG[5K] greatly increase the activity of Chol-DsiRNA against a stably expressed reporter mRNA in primary murine syngeneic breast tumors after daily i.v. dosing. Here, we provide a more thorough preliminary preclinical study of Chol-DsiRNA polyplexes against the therapeutically relevant target protein, STAT3. We found that Chol-DsiSTAT3 polyplexes greatly increase plasma exposure, distribution, potency, and therapeutic activity of Chol-DsiSTAT3 in primary murine syngeneic 4T1 breast tumors after i.v. administration. Furthermore, inactive Chol-DsiCTRL polyplexes are well tolerated by healthy female BALB/c mice after chronic i.v. administration at 50 mg Chol-DsiCTRL/kg over 28 days. Thus, Chol-DsiRNA polyplexes may be a good candidate for Phase I clinical trials to improve the treatment of breast cancer and other solid tumors.

Original languageEnglish (US)
Article number102363
JournalNanomedicine: Nanotechnology, Biology, and Medicine
StatePublished - Apr 2021


  • Chol-DsiRNA polymer micelles
  • Chol-siRNA polymer micelles
  • Drug delivery
  • DsiRNA
  • RNA interference

ASJC Scopus subject areas

  • Bioengineering
  • Medicine (miscellaneous)
  • Molecular Medicine
  • Biomedical Engineering
  • Materials Science(all)
  • Pharmaceutical Science

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