title: Codelivery of zoledronic acid and doublestranded RNA from core-shell nanoparticles.
abstract: BACKGROUND
  Zoledronic acid, an inhibitor of osteoclast-mediated bone resorption, has been shown to have both direct and indirect antitumor activity. However, its use in extraskeletal malignancy is limited due to rapid uptake and accumulation within bone. Polyinosinic acid-polycytidylic acid [poly (I:C)] is a synthetic double-stranded RNA with direct antitumor cytotoxicity if it can be delivered to tumor cells intracellularly.
  
  
  METHODS
  Cationic lipid-coated calcium phosphate nanoparticles (LCP) were developed to enable intracellular codelivery of zoledronic acid and poly (I:C). LCP codelivering zoledronic acid and poly (I:C) were prepared using an ethanol injection method. Briefly, the ethanol solution of lipids was rapidly injected into newly formed calcium phosphate crystals containing poly (I:C) and zoledronic acid, and the mixture was then sonicated briefly to form LCP. The LCP were fully characterized for mean diameter size and zeta potential, efficiency in loading zoledronic acid, cytotoxic effect in a B16BL6 melanoma cell line in vitro, and antitumor effect in B16BL6 melanoma-bearing mice.
  
  
  RESULTS
  LCP with a mean diameter around 200 nm and a narrow size distribution (polydispersity index 0.17) and high zoledronic acid encapsulation efficiency (94%) were achieved. LCP loaded with zoledronic acid and poly (I:C) had significantly greater antitumor activity than the free drugs in the B16BL6 melanoma cell line (P < 0.05). Furthermore, codelivery of zoledronic acid and poly (I:C) by LCP had higher cytotoxicity than delivering poly (I:C) alone by LCP (P < 0.05), indicating a synergism between zoledronic acid and poly (I:C). Finally, the antitumor study in melanoma-bearing mice also demonstrated synergism between zoledronic acid and poly (I:C) codelivered by LCP.
  
  
  CONCLUSIONS
  Cationic lipid-coated calcium phosphate nanoparticles constructed for codelivery of zoledronic acid and double-stranded RNA poly (I:C) had better antitumor activity both in vitro and in vivo. Future preclinical development of LCP encapsulating zoledronic acid and poly (I:C) for the treatment of human cancer is under way.
authors: Department of Pharmaceutical Sciences, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA.
authors: Li
authors: L
authors: Chen
authors: Yunfei
authors: Y
authors: Ding
authors: Yongzhong
authors: Y
authors: Wang
authors: Xingrong
authors: X
authors: Liu
authors: Rj
authors: R
authors: Babu
authors: Wr
authors: W
authors: Ravis
authors: Weili
authors: W
authors: Yan
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004164:Diphosphonates / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D004355:Drug Stability; D005260:Female; D007093:Imidazoles / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D008546:Melanoma, Experimental / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D053758:Nanoparticles / Q000008:administration & dosage* / Q000737:chemistry; D010316:Particle Size; D011070:Poly I-C / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D012330:RNA, Double-Stranded / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D011897:Random Allocation; D000077211:Zoledronic Acid
chemical_list: D004164:Diphosphonates; D007093:Imidazoles; D012330:RNA, Double-Stranded; D000077211:Zoledronic Acid; D011070:Poly I-C
keywords: calcium phosphate; codelivery; double-stranded RNA; lipid-coated nanoparticles; poly (I:C); zoledronic acid