Detecting human melanoma cell re-differentiation following BRAF or heat shock protein 90 inhibition using photoacoustic and magnetic resonance imaging

Sci Rep. 2017 Aug 15;7(1):8215. doi: 10.1038/s41598-017-07864-8.

Abstract

Targeted therapies specific to the BRAF-MEK-ERK signaling pathway have shown great promise in the treatment of malignant melanoma in the last few years, with these drugs now commonly used in clinic. Melanoma cells treated using these agents are known to exhibit increased levels of melanin pigment and tyrosinase activity. In this study we assessed the potential of non-invasive imaging approaches (photoacoustic imaging (PAI) and magnetic resonance imaging (MRI)) to detect melanin induction in SKMEL28 human melanoma cells, following inhibition of Hsp90 and BRAF signaling using 17-AAG and vemurafenib, respectively. We confirmed, using western blot and spectrophotometry, that Hsp90 or BRAF inhibitor-induced melanoma cell differentiation resulted in an upregulation of tyrosinase and melanin expression levels, in comparison to control cells. This post-treatment increase in cellular pigmentation induced a significant increase in PAI signals that are spectrally identifiable and shortening of the MRI relaxation times T 1 and [Formula: see text]. This proof-of-concept study demonstrates the potential of MRI and PAI for detecting the downstream cellular changes induced by Hsp90 and BRAF-MEK-targeted therapies in melanoma cells with potential significance for in vivo imaging.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Cell Differentiation / drug effects
  • Cell Line, Tumor
  • Cell Proliferation
  • HSP90 Heat-Shock Proteins / antagonists & inhibitors*
  • Humans
  • Magnetic Resonance Imaging*
  • Melanoma / diagnosis*
  • Melanoma / metabolism*
  • Photoacoustic Techniques*
  • Pigments, Biological / biosynthesis
  • Protein Kinase Inhibitors / pharmacology*
  • Proto-Oncogene Proteins B-raf / antagonists & inhibitors*

Substances

  • Antineoplastic Agents
  • HSP90 Heat-Shock Proteins
  • Pigments, Biological
  • Protein Kinase Inhibitors
  • Proto-Oncogene Proteins B-raf