Yellow fluorescent protein (YFP) as a biosensor for intracellular iodide in thyroid cancer cells

Research output: Contribution to conference (unpublished)Abstractpeer-review


  • Katie Baker
  • Caitlin Thornton
  • Mohammed Alshahrani
  • Rebecca Thompson
  • Peter Haggie
  • Alan Verkman

External organisations

  • UCSF


New drug strategies are urgently needed to improve radioiodine uptake and efficiently ablate thyroid cancer cells thereby minimising the risk of recurrent disease. High-throughput screening (HTS) offers a promising approach to identify new candidate drugs that induce sodium iodide symporter (NIS) function to promote iodide uptake. However, significant progress has been limited by a lack of thyroid cell-based assays amenable to HTS.

Here, we investigated a thyroid cancer cell reporter consisting of a modified version of the yellow fluorescent protein (YFP-H148Q/I152L/F46L) as a biosensor of intracellular iodide. Iodide uptake was monitored by quenching of YFP-H148Q/I152L/F46L fluorescence using a HTS reader PHERAstar FSX.

We generated a panel of human thyroid cancer cell lines with stable overexpression of YFP-H148Q/I152L/F46L either alone or together with NIS. Importantly, the YFP cell-based assay was sensitive towards iodide uptake and robust with a Z’ value of 0.82 (e.g. maximal 12% YFP reduction at 8mM dose versus 40% YFP reduction at 68mM dose after 10 minutes). Kinetic measurements demonstrated that iodide uptake was rapid within 2 minutes with maximal quenching at 5-10 minutes depending on thyroid cancer cell type. Further, we validated the assay with a panel of reference compounds, which showed that the Src inhibitor PP1 was the most potent in enhancing iodide uptake, followed by selumetinib and SAHA.

In summary, we have developed a robust thyroid cell reporter assay that is amenable for HTS. Enhancement of iodide uptake is currently being evaluated utilizing this assay and a library of ~5300 well-annotated drugs.


Original languageEnglish
Publication statusPublished - 15 May 2018
EventThe 66th British Thyroid Association Annual Meeting - ELGAR CONCERT HALL, BRAMALL MUSIC BUILDING, UNIVERSITY OF BIRMINGHAM, , Birmingham, United Kingdom
Duration: 14 May 201815 May 2018


ConferenceThe 66th British Thyroid Association Annual Meeting
CountryUnited Kingdom
Internet address