Evaluation of somatostatin and nucleolin receptors for therapeutic delivery in non-small cell lung cancer stem cells applying the somatostatin-analog DOTATATE and the nucleolin-targeting aptamer AS1411

PLoS One. 2017 May 22;12(5):e0178286. doi: 10.1371/journal.pone.0178286. eCollection 2017.

Abstract

Cancer stem cells represent the putative tumor-driving subpopulation thought to account for drug resistance, relapse, and metastatic spread of epithelial and other cancer types. Accordingly, cell surface markers for therapeutic delivery to cancer stem cells are subject of intense research. Somatostatin receptor 2 and nucleolin are known to be overexpressed by various cancer types, which have elicited comprehensive efforts to explore their therapeutic utilization. Here, we evaluated somatostatin receptor 2 targeting and nucleolin targeting for therapeutic delivery to cancer stem cells from lung cancer. Nucleolin is expressed highly but not selectively, while somatostatin receptor 2 is expressed selectively but not highly by cancer cells. The non-small cell lung cancer cell lines A549 and H1299, displayed average levels of both surface molecules as judged based on analysis of a larger cell line panel. H1299 compared to A549 cells showed significantly elevated sphere-forming capacity, indicating higher cancer stem cell content, thus qualifying as suitable test system. Nucleolin-targeting 57Co-DOTA-AS1411 aptamer showed efficient internalization by cancer cells and, remarkably, at even higher efficiency by cancer stem cells. In contrast, somatostatin receptor 2 expression levels were not sufficiently high in H1299 cells to confer efficient uptake by either non-cancer stem cells or cancer stem cells. The data provides indication that the nucleolin-targeting AS1411 aptamer might be used for therapeutic delivery to non-small cell lung cancer stem cells.

Publication types

  • Evaluation Study

MeSH terms

  • Apoptosis / drug effects
  • Aptamers, Nucleotide / pharmacology*
  • Carcinoma, Non-Small-Cell Lung / drug therapy*
  • Carcinoma, Non-Small-Cell Lung / metabolism
  • Carcinoma, Non-Small-Cell Lung / pathology
  • Cell Proliferation / drug effects
  • Drug Delivery Systems
  • Heterocyclic Compounds, 1-Ring / chemistry*
  • Humans
  • Lung Neoplasms / drug therapy
  • Lung Neoplasms / metabolism
  • Lung Neoplasms / pathology
  • Neoplastic Stem Cells / drug effects*
  • Neoplastic Stem Cells / metabolism
  • Neoplastic Stem Cells / pathology
  • Nucleolin
  • Phosphoproteins / antagonists & inhibitors*
  • RNA-Binding Proteins / antagonists & inhibitors*
  • Receptors, Somatostatin / metabolism*
  • Somatostatin / analogs & derivatives*
  • Somatostatin / pharmacology
  • Tumor Cells, Cultured

Substances

  • Aptamers, Nucleotide
  • Heterocyclic Compounds, 1-Ring
  • Phosphoproteins
  • RNA-Binding Proteins
  • Receptors, Somatostatin
  • 1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetic acid
  • Somatostatin
  • somatostatin receptor 2

Grants and funding

This work was supported by: Danish Council for Independent Research; Medical Sciences (DFF-4004-00268) http://ufm.dk/forskning-og-innovation/rad-og-udvalg/det-frie-forskningsrad, Receiver: JM; Lundbeck Foundation grant to the Nanomedicine Research Center for Cancer Stem Cell-Targeting Therapeutics (NanoCAN) http://www.lundbeckfonden.com/, Receiver: JM.