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Transcription Factor HOXA9 is Linked to the Calcification and Invasion of Papillary Thyroid Carcinoma
- Author(s)
- JIN YILAN
- Advisor
- 정윤석
- Department
- 일반대학원 의학과
- Publisher
- The Graduate School, Ajou University
- Publication Year
- 2020-02
- Language
- eng
- Alternative Abstract
- Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer, representing 75 to 85 percent of all thyroid cancer cases. Calcification is one of the important characteristic feature for the diagnosis of papillary thyroid carcinoma. Runt-related transcription factor 2 (RUNX2), a master transcription factor associated with osteogenic differentiation, is reportedly related to PTC calcification and invasiveness. However, its regulatory role in this process is somewhat uncharacterized. Here, I attempted to identify gene that regulates RUNX2 and to clarify its function in PTC calcification and carcinogenesis. The expression of RUNX2-upstream genes was evaluated by semi-quantitative reverse-transcriptase PCR and quantitative real-time PCR in normal thyroid cell line Nthy-Ori 3-1 and the PTC cell lines TPC1 and BHP10-3. After cloning the RUNX2 promoter, luciferase assay and chromatin immunoprecipitation assay were performed with the primary candidate gene - homeobox family A9 (HOXA9). I found that RUNX2 promoter activity and binding ability were enhanced by HOXA9. Over-expression of HOXA9 was found to enhance alkaline phosphatase activity, mineralization, and the ability of in vitro cell migration and invasion, whereas downregulation of HOXA9 showed the opposite effects. To confirm the results from in vitro promoter, mineralization and carcinogenesis assays, I evaluated haematoxylin and eosin staining in human thyroid cancer tissue specimens from thyroid carcinoma patients and identified immunohistochemistry to verify the expression of RUNX2 and HOXA9 in serial calcified malignant thyroid cancer tissues. Haematoxylin and eosin staining and immunohistochemistry results showed that the expression of RUNX2 and HOXA9 were found in calcified cancer tissues simultaneously. Next, I performed RUNX2 down regulation experiment in the control cell lines and HOXA9 overexpressed system with the normal cell line Nthy-Ori 3-1 and PTC cell lines TPC1 and BHP10-3. Further, mineralization assay, wound healing assay, and transwell assay were performed in these cells. Mineralization were decreased in all RUNX2 downregulated cells, and alkaline phosphatase activity in Nthy-Ori 3-1 and BHP10-3 cells was enhanced in the RUNX2 knockdowned and HOXA9 overexpressed cells compared to the RUNX2 knockdowned in control cells. Furthermore, migration ability was all decreased in RUNX2 knockdowned cells compared to the control cells, and invasion ability was enhanced in the RUNX2 knockdown groups with HOXA9 overexpression compared to that in respective RUNX2 knockdown with control groups. These results indicated that HOXA9, as a positive regulator of RUNX2, can enhance calcification, migration, and invasion in PTC. These data can improve the understanding of the molecular mechanisms of calcification in papillary thyroid carcinoma as well as tumorigenesis.
- Fulltext
- Appears in Collections:
- Graduate School of Ajou University > Department of Medicine > 4. Theses(Ph.D)
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