Correlation of pendrin with ¹³¹Iodine uptake in post-NAI treated thyroid cancer animal model

Radioactive iodine (RAI) refractoriness develops in the background of a loss of thyroid differentiation features representing major therapeutic challenges in thyroid cancer management. Studies have reported decreased or loss of pendrin (SLC26A4 gene) expression in thyroid tumours, signifying the role of pendrin in the impaired ability of thyroid cancer cells for uptake and concentration of iodine. As acute iodide treatment has been shown to increase SLC26A4 mRNA, the study of pendrin expression in malignant tissues is of interest. Hence, we focused to evaluate the pendrin expression and ¹³¹I uptake in an N-bis-(2-hydroxypropyl) nitrosamine (DHPN) induced thyroid cancer model in Wistar rats followed by a single dose of sodium iodide (NAI) treatment to see if any change occurs in RAI uptake. ¹³¹I uptake by scintigraphy showed thyroid uptake values of 10.16±1.6 and 13.13±0.115 in DHPN-treated and control groups respectively at 24h. However, post-NAI treatment decreasing patterns at 24h, 48h and 72h were observed in a few animals similar to the control. This could be attributed to a phenomenon known as the "Wolff-Chaikoff effect" which results due to acute iodide excess that transiently impairs thyroid hormone synthesis. However, the rising pattern of ¹³¹I uptake was also observed in a few DHPN-induced thyroid cancer animals compared to the control, which could perhaps be related to the effect of iodide excess treatment influencing the expression and functionality of pendrin. In conclusion, further research is warranted to verify the role of NAI in the expression of Pendrin in conjunction with animal species and age; along with the dose and exposure time of NAI. In addition, the expression and quantification of pendrin at the molecular level entail being assessed to enhance its utility in the management of RAI refractory human thyroid cancer patients