Effects of Thyroid Stimulating Hormone on Tumor Growth by Modulating Tumor Microenvironment in Thyroid Cancer

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dc.description학위논문 (석사)-- 서울대학교 대학원 : 의학과 중개의학 전공, 2016. 2. 박영주.-
dc.description.abstractIntroduction: The stimulatory effect of thyroid stimulating hormone (TSH) through TSH receptor signal pathways on the growth of thyrocytes is well-demonstrated. Differentiated thyroid cancer (DTC) expresses TSH receptors and retains responsiveness to TSH. Thus, TSH suppression has been used as an important and effective treatment in patients with DTC. Since tumor microenvironment including angiogenesis has a crucial role in cancer progression and metastasis, we investigated whether the effects of TSH on tumor growth are also mediated by tumor microenvironment using a mouse model of DTC.
Materials and Methods: BHP10-3SC DTC cells, which express TSH receptors, were subcutaneously implanted on 7-week-old BALB/c nu/nu mice. When the greater diameter of tumor became 5 mm or larger, recombinant human TSH (rhTSH, 1.5 μg/g) or vehicle was started to be injected intraperitoneally. Tumor size was measured every 3 days. After 15 days, tumor histology was examined and vascular endothelial growth factor (VEGF) mRNA expression was analyzed using real time-PCR. For supporting in vivo results, in vitro experiments to demonstrate TSH effects on angiogenesis were performed in BHP10-3SC and human endothelial cells.
Results: Tumors in rhTSH group grew more rapidly than controls, and there was a significant difference in the tumor volume (on day 15, 1733.4 ± 793.5 mm3 vs. 1148.8 ± 471.1 mm3, respectively, P = 0.010). The vascular density in tumors was significantly increased in rhTSH group (13.8 ± 0.8% vs. 5.7 ± 0.8% in control, P = 0.021). Moreover, more tortuous and dilated vessels were observed in tumors of rhTSH group compared with controls (23.0 ± 1.7 μm vs. 7.4 ± 0.5 μm in vascular diameter, respectively, P <0.001). In addition, the macrophage infiltration in tumors was significantly increased in rhTSH group (27.6 ± 11.6% vs. 12.1 ± 4.3% in control, P = 0.004). In vitro experiments showed that TSH induced a significant up-regulation of VEGF-A mRNA expression in BHP10-3SC cells. Conditioned medium of TSH-treated BHP10-3SC cells (TSH-CM) contained higher concentration of VEGF-A than saline-treated CM (control-CM). Finally, treatment of TSH-CM significantly enhance potentials of cell migration and tube formation in human endothelial cells, HMVEC or HUVEC.
Conclusions: TSH supports the growth of thyroid cancer via enhancing abnormal vasculature and subsequent recruitment of macrophages in tumor microenvironments.
dc.description.tableofcontentsIntroduction 1
1. Positive correlation between serum TSH level and tumor progression in thyroid cancer patients 1
2. Regulatory mechanism of TSH on growth of differentiated thyroid tumor cells 1
3. Vascular endothelial growth factor (VEGF)-regulated angiogenesis in thyroid cancer 2
4. Tumor-associated macrophage (TAM) in thyroid cancer 4
5. Aims of Study 4

Materials and Methods 6
1. Mice 6
2. Cell cultures 6
3. Experimental protocols of TSH treatment on mouse tumor model 8
4. Measurement of tumor size 13
5. Measurement of serum thyroid hormone 14
6. Immunofluorescence, H&E, and immunohistochemistry 14
7. Electron microscopy 15
8. RNA extraction and real time-PCR analysis 16
9. Conditioned medium of TSH-treated BHP10-SC cells 17
10. Measurement of VEGF-A protein levels 17
11. Cell migration and tube formation assay 17
12. Morphometric analysis 18
13. Statistical analysis 19

Results 20
1. Time effects of TSH on angiogenesis in normal thyroid and thyroid cancer 20
1) Effects of TSH on thyrocytes and angiogenesis in thyroid gland 20
2) Effects of TSH on angiogenesis in thyroid cancer 21
2. Effects of TSH on tumor growth 26
1) Effects of cell passages on tumorigenesis of xenografts 26
2) Effects of TSH on tumor growth 29
3. In vivo effects of TSH on angiogenesis 34
1) Angiogenesis and vascular permeability 34
2) Endothelial fenestration 34
3) VEGF expression 35
4. In vivo effects of TSH on TAM 39
5. In vitro effects of TSH on angiogenesis 41

Discussion 48

References 52

Abstract in Korean 58
dc.format.extent5566475 bytes-
dc.publisher서울대학교 대학원-
dc.subjectthyroid stimulating hormone-
dc.subjectthyroid cancer-
dc.subjecttumor growth-
dc.titleEffects of Thyroid Stimulating Hormone on Tumor Growth by Modulating Tumor Microenvironment in Thyroid Cancer-
dc.contributor.affiliation의과대학 의학과-
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College of Medicine/School of Medicine (의과대학/대학원)Dept. of Medicine (의학과)Theses (Master's Degree_의학과)
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