A novel PEGylated liposome-encapsulated SANT75 suppresses tumor growth through inhibiting hedgehog signaling pathway

PLoS One. 2013;8(4):e60266. doi: 10.1371/journal.pone.0060266. Epub 2013 Apr 1.

Abstract

The Hedgehog (Hh) pathway inhibitors have shown great promise in cancer therapeutics. SANT75, a novel compound we previously designed to specially inhibit the Smoothened (SMO) protein in the Hh pathway, has greater inhibitory potency than many of commonly used Hh inhibitors. However, preclinical studies of SANT75 revealed water insolubility and acute toxicity. To overcome these limitations, we developed a liposomal formulation of SANT75 and investigated its antitumor efficacy in vitro and in vivo. We encapsulated SANT75 into PEGylated liposome and the mean particle size distribution and zeta-potential (ZP) of liposomes were optimized. Using the Shh-light2 cell and Gli-GFP or Flk-GFP transgenic reporter zebrafish, we confirmed that liposome-encapsulated SANT75 inhibited Hh activity with similar potency as the original SANT75. SANT75 encapsulated into liposome exerted strong tumor growth-inhibiting effects in vitro and in vivo. In addition, the liposomal SANT75 therapy efficiently improved the survival time of tumor-bearing mice without obvious systemic toxicity. The pathological morphology and immunohistochemistry staining revealed that liposomal SANT75 induced tumor cell apoptosis, inhibited tumor angiogenesis as assessed by CD31 and down-regulated the expression of Hh target protein Gli-1 in tumor tissues. Our findings suggest that liposomal formulated SANT75 has improved solubility and bioavailability and should be further developed as a drug candidate for treating tumors with abnormally high Hh activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / chemical synthesis
  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Drug Compounding
  • Embryo, Nonmammalian
  • Female
  • Gene Expression Regulation, Neoplastic / drug effects*
  • Genes, Reporter
  • Green Fluorescent Proteins
  • Humans
  • Liposomes / chemistry*
  • Mice
  • Mice, Inbred C57BL
  • Oncogene Proteins / antagonists & inhibitors*
  • Oncogene Proteins / genetics
  • Oncogene Proteins / metabolism
  • Polyethylene Glycols / chemistry
  • Receptors, G-Protein-Coupled / antagonists & inhibitors*
  • Receptors, G-Protein-Coupled / genetics
  • Receptors, G-Protein-Coupled / metabolism
  • Signal Transduction / drug effects*
  • Smoothened Receptor
  • Trans-Activators / antagonists & inhibitors*
  • Trans-Activators / genetics
  • Trans-Activators / metabolism
  • Tumor Burden / drug effects
  • Xenograft Model Antitumor Assays
  • Zebrafish
  • Zinc Finger Protein GLI1

Substances

  • Antineoplastic Agents
  • Liposomes
  • Oncogene Proteins
  • Receptors, G-Protein-Coupled
  • Smo protein, mouse
  • Smoothened Receptor
  • Trans-Activators
  • Zinc Finger Protein GLI1
  • Green Fluorescent Proteins
  • Polyethylene Glycols

Grants and funding

This work was supported by the National S&T Major project(2012ZX09501001-003). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.