The Expression Analysis Of NDRG2 In Human Thyroid Tumors And The Functional Research In Proliferation And Invasion Of The Thyroid Cancer Cell Line

Thyroid cancer is one of the common and frequent encountered diseases. Although the occurrence of thyroid cancer constitutes only about 1%of the total human cancers,it is the most common malignant disease in endocrine system and threats human health seriously.Except for the relative better prognosis of the surgical operation,the combined treatment including endocrine hormone and radioactive isotope therapy to papillary thyroid carcinoma,the prognosis of other pathological types is still bad.So,it is very impending to deeply investigate the carcinogenesis mechanism of thyroid tumor.And the discovery and functional research of the thyroid cancer related genes are very intriguing.Human NDRG2(N-Myc downstream-regulated gene) is the novel gene cloned by the department of biochemsitry and molecular chemistry of our university.The primary research work about NDRG2 shows that Ndrg2 expresses ubiquitously in almost all normal tissues.However,it expresses very low or undetectable in nearly 10 tumor tissues or cell lines including colon cancers, glioma,leukemia,lymphoma and parotid cancers etc.It is presumptive that human NDRG2 is close to tumor progression and we believe NDRG2 is one novel candidate of tumor supressor gene.Especially,it is confirmed that NDRG2 is one of the downstream regulated target gene of Myc,the famous oncogene.Untill now,there isn't the research report about NDRG2 with thyroid cancer. So,firstly,we should elucidate the expression profiling of human NDRG2 in thyroid tumors.The first part of our work to answer this question.The preliminary detection of Ndrg2 expression in thyroid tumor is examined using the tissue microarray.With the immunostainning analysis,the conspicuous different expression pattern of Ndrg2 was detected between thyroid carcinoma and the normal tissues.We find that Ndrg2 expresses very abundant in the normal thyroid and lower or undetectable in much types of thyroid cancers statistically significant.Further,we get the similar results by immunochemistry and western blotting analysis in the collected thyroid cancer samples.Our results demonstrate that the protein level of Ndrg2 differentiate between the nornal and tumor thyroid tissues.Based on the detection of Ndrg2 protein expression in thyroid cancer tissues,real-time PCR was used to investigate NDRG2 mRNA level in thyroid tissue with carcinoma.Expectably,the expression of NDRG2 mRNA in thyroid cancer tissues is relatively low than the normal group,which is accordant with the protein level.Thus,we believe that human NDRG2 is the differentiated expression gene between normal thyroid tissues and tumors.To further explore the potential function of human NDRG2 during the progression of thyroid cancer,we overexpress NDRG2 in papillary thyroid cancer cells FTC-13 3 by the infection of NDRG2 adenovirus.RT-PCR and Western-blot methods are used to confirm the expression status MTT,flat clone formation and cell cycle analysis demonstrate that overexpression of NDRG2 could inhibit the proliferation of thyroid cancer cells significantly.Trans-well and scratch test show that NDRG2 overexpression also causes the decrease of cell metastasis ablity.Our present results demonstrate that NDRG2 is the differentiated expression gene between normal thyroid tissues and tumors.The overexpression of human NDRG2 can suppress the proliferation and metastasis of thyroid cancer cells.It is presumable that NDRG2 participates the carcinogenesis and development of thyroid tumor.The data enriches the work of human NDRG2 with thyroid cancer and lay the foundation for the research of thyroid tumor.