Theranostic properties of a survivin-directed molecular beacon in human melanoma cells

PLoS One. 2014 Dec 11;9(12):e114588. doi: 10.1371/journal.pone.0114588. eCollection 2014.

Abstract

Survivin is an inhibitor of apoptosis overexpressed in different types of tumors and undetectable in most terminally differentiated normal tissues. In the current study, we sought to evaluate the in vitro theranostic properties of a molecular beacon-oligodeoxynucleotide (MB) that targets survivin mRNA. We used laser scanning confocal microscopy to study MB delivery in living cells and real-time PCR and western blot to assess selective survivin-targeting in human malignant melanoma cells. We further assess the pro-apoptotic effect of MB by measuring internucleosomal DNA fragmentation, dissipation of mitochondrial membrane potential (MMP) and changes in nuclear morphology. Transfection of MB into A375 and 501 Mel cells generated high signal intensity from the cytoplasm, while no signal was detected in the extracellular environment and in survivin-negative cells (i.e., human melanocytes and monocytes). MB time dependently decreased survivin mRNA and protein expression in melanoma cells with the maximum effect reached at 72 h. Treatment of melanoma cells with MB induced apoptosis by significant changes in MMP, accumulation of histone-complexed DNA fragments in the cytoplasm and nuclear condensation. MB also enhanced the pro-apoptotic effect of standard chemotherapeutic drugs tested at clinically relevant concentrations. The MB tested in the current study conjugates the ability of imaging with the pharmacological silencing activity against survivin mRNA in human melanoma cells and may represent an innovative approach for cancer diagnosis and treatment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology
  • Apoptosis / drug effects
  • Apoptosis / genetics
  • Cell Line, Tumor
  • DNA Fragmentation / drug effects
  • Down-Regulation / drug effects
  • Down-Regulation / genetics
  • Gene Expression Regulation, Neoplastic / genetics
  • Humans
  • Inhibitor of Apoptosis Proteins / biosynthesis
  • Inhibitor of Apoptosis Proteins / genetics*
  • Melanoma / pathology*
  • Membrane Potential, Mitochondrial / drug effects
  • Membrane Potential, Mitochondrial / genetics
  • Oligonucleotide Probes / genetics
  • Oligonucleotide Probes / metabolism*
  • Oligonucleotide Probes / therapeutic use
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Substrate Specificity
  • Survivin

Substances

  • Antineoplastic Agents
  • BIRC5 protein, human
  • Inhibitor of Apoptosis Proteins
  • Oligonucleotide Probes
  • RNA, Messenger
  • Survivin

Grants and funding

This work was supported by the regional project NANOCELL – Optical Nanosensors inside cells (PAR FAS REGIONE TOSCANA Linea 1.1.a.3), by the national flagship project NANOMAX, and by Association against Melanoma Onlus (Italy). The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.