Human sodium–iodide symporter (hNIS) gene expression is inhibited by a trans-active transcriptional repressor, NIS-repressor, containing PARP-1 in thyroid cancer cells

Abstract

Radioiodine remains the only tumoricidal therapy for disseminated thyroid carcinomas; however, dedifferentiated tumors lose the expression of human sodium-iodide symporter (hNIS) gene, and cannot respond to this treatment. Previous studies suggested that a trans-active protein factor (NIS-repressor) represses endogenous hNIS transcription, likely contributing to the loss of radioiodine uptake, and defined the NIS-repressor binding site (NRBS) in the proximal hNIS promoter. Using electrophoretic mobility shift assay (EMSA), we found evidence of NIS-repressor in the nuclear extract from KAK-1 cells, and confirmed this result using nuclear extracts prepared from multiple verified thyroid cell lines. Luciferase reporter assays of hNIS promoter constructs and EMSA were used to define two core sequences, NRBS-P and NRBS-D, in the hNIS promoter as the binding sites for NIS-repressor. Electrophoretic analysis of KAK-1 nuclear extract proteins cross-linked with NRBS-P suggests that NIS-repressor is a protein complex. Analysis of KAK-1 nuclear extract proteins bound to NRBS-P, via liquid chromatography coupled with tandem mass spectroscopy, demonstrated poly(ADP-ribose) polymerase-1 (PARP-1) as a NIS-repressor component. Pharmacological inhibition of PARP-1 enzymatic activity using PJ34 stimulated both the luciferase reporter activity driven by hNIS promoter and the endogenous hNIS mRNA level. Supershift studies suggest that thyroid transcription factor 2 (TTF-2) is also associated with the NIS-repressor complex. NIS-repressor, including its PARP-1 component, presents a potential therapeutic target to restore radioiodine uptake in dedifferentiated thyroid carcinomas.

The PARP inhibitor PJ34 modifies proliferation, NIS expression and epigenetic marks in thyroid cancer cell lines

“…As shown in panel A of Instead, no effect was detected on transcriptional activity of NIS-415. These data are coherent to those of Li and Ain (Li and Ain, 2010) that show the presence of a PARP-1 containing repressor binding site in the region -648/-620 bp of the NIS promoter. However, the increase that we observed upon PJ34 treatment is lower then that reported by Li at Ain.…”

“…Therefore, we evaluated this effect through an MTT bioassay in four human thyroid cancer cell lines: TPC1 and BCPAP cell lines (from papillary carcinoma), WRO cells (from follicular carcinoma), and FRO (from human undifferentiated carcinoma) by using the PARPi PJ34. This compound has been widely used to inhibit PARP-1 activity (Jagtap and Szabo', 2005;Chevanne et al, 2010;Li and Ain, 2010;Madison et al, 2011). The indicated cell lines were treated with PJ34 at doses comparable to those used in other studies (6 lM, 30 lM, 60 lM) for 24, 48 and 72 h. Results are shown in Fig.…”

“…Moreover, the presence of a trans-acting repressor of NIS transcription which may act in thyroid cancer cells has been also hypothesized (Li et al, 2007). Recently Li and Ain (2010) demonstrated human poly(ADP-ribose) polymerase-1 (PARP-1) to be a likely component of a NIS-repressor complex present in thyroid cancer cells. Interestingly, several thyroid-specific transcription factors, including PAX8 and TTF1 interact with PARP proteins (Di Palma et al, 2008;Maeda et al, 2006).…”

Afamin promotes glucose metabolism in papillary thyroid carcinoma

“…In thyroid cancer, it has been reported that PARP1 could be a component of the sodium e iodide symporter (NIS) repressor protein complex and in various thyroid cancer cell lines PARP inhibition could increase NIS gene expression through a particular modulation of transcriptional regulatory mechanisms (Lavarone et al, 2013;Li and Ain, 2010). In our current pilot study, we found that over-expression of human AFM in PTC cells could increase the expression of PARP1 which further indicated the oncogenic effect of AFM.…”

Clinical study on radiofrequency combined with 131I therapy for dedifferentiated thyroid carcinomas

“…Judgment of curative effect began to valuate in 6 month after complete therapy with clinical symptoms, CT, X ray , B ultrasonic diagnostic equipments and so on in according to RECIST curative standard of solid tumor combined radionuclide imaging and blood Tg value [6] . Therapeutic effect were sorted complete response, partial response, steady disease and progressive disease, objective curative result equal to complete response and partial response; toxic reaction referred to the standard of RECIST.…”