Therapeutic effects of adenovirus-mediated CD and NIS expression combined with NaI/5-FC on human thyroid cancer.

Thyroid cancer is the most common type of malignant endocrine tumor diagnosed. Previous studies have indicated that gene therapy is the most promising and effective therapeutic method for thyroid cancer. Therefore, in the present study, NaI/5-fluorocytosine (5-FC) treatment was combined with cytosine deaminase (CD, encoded by the gene) and sodium iodide symporter (NIS, encoded by the gene) to act together as a therapeutic tool for thyroid cancer. The present study explored the combined cytotoxic effects of adenovirus-mediated CD and NIS under the control of the progression elevated gene-3 () promoter (Ad-PEG-3-CD-NIS) with NaI/5-FC against the human thyroid cancer TT cell line . The fragment was obtained by polymerase chain reaction (PCR) using rat genomic DNA as the template, and then Ad- was constructed using I. TT cells were transfected by recombinant adenovirus. The method of reverse transcription-quantitative PCR was performed to test the expression of CD and NIS at the level of transcription. The morphological change was assessed by fluorescence microscopy and investigated by western blot analysis. An MTT assay was used to determine the number of living cells inhibited by single or combination therapies on TT cells. The results indicated that the was successfully cloned, and was also positively regulated in 293 cells. and genes were highly expressed in TT cells. NaI combined with 5-FC significantly decreased the human thyroid cancer cells. In conclusion, combination therapy of Ad- and NaI/5-FC induces significantly more apoptotic characteristics than either single treatment with Ad- or NaI/5-FC, and low doses of Ad- enhanced the cytotoxic effects.