BRAF遺伝子変異によるNF-kB活性化と甲状腺がん細胞浸潤亢進の関係

長崎大学学位論文 学位記番号:博(医歯薬)甲第74号 学位授与年月日:平成18年11月1

Nuclear Factor-Kappa B Inhibition Can Enhance Apoptosis of Differentiated Thyroid Cancer Cells Induced by 131I

Objective: To evaluate changes of nuclear factor-kappa B (NF-kB) during radioiodine 131 ( 131 I) therapy and whether NF-kB inhibition could enhance 131 I-induced apoptosis in differentiated thyroid cancer (DTC) cells in a synergistic manner. Methods: Three human DTC cell lines were used. NF-kB inhibition was achieved by using a NF-kB inhibitor (Bay 11-7082) or by p65 siRNA transfection. Methyl-thiazolyl-tetrazolium assay was performed for cell viability assessment. DNA-binding assay, luciferase reporter assay, and Western blot were adopted to determine function and expression changes of NF-kB. Then NF-kB regulated anti-apoptotic factors XIAP, cIAP1, and Bcl-xL were measured. Apoptosis was analyzed by Western blot for caspase 3 and PARP, and by flow cytometry as well. An iodide uptake assay was performed to determine whether NF-kB inhibition could influence radioactive iodide uptake. Results: The methyl-thiazolyl-tetrazolium assay showed significant decrease of viable cells by combination therapy than by mono-therapies. The DNA-binding assay and luciferase reporter assay showed enhanced NF-kB function and reporter gene activities due to 131 I, yet significant suppression was achieved by NF-kB inhibition. Western blot proved 131 I could increase nuclear NF-kB concentration, while NF-kB inhibition reduced NF-kB concentration. Western blot also demonstrated significant up-regulation of XIAP, cIAP1, and Bcl-xL after 131 I therapy. And inhibition of NF-kB could significantly downregulate these factors. Finally, synergism induced by combined therapy was displayed by significant enhancements o

Postnatal Expression of BRAFV600E Does Not Induce Thyroid Cancer in Mouse Models of Thyroid Papillary Carcinoma

The mutant BRAF (BRAFV600E) is the most common genetic alteration in papillary thyroid carcinomas (PTCs). The oncogenicity of this mutation has been shown by some genetically engineered mouse models. However, in these mice, BRAFV600E is expressed in all the thyroid cells from the fetal periods, and suppresses thyroid function, thereby leading to TSH elevation, which by itself promotes thyroid tumorigenesis. To overcome these problems, we exploited 2 different approaches, both of which allowed temporally and spatially restricted expression of BRAFV600E in the thyroid glands. First, we generated conditional transgenic mice harboring the loxP-neoR-loxP-BRAFV600Einternal ribosome entry site-green fluorescent protein sequence [Tg(LNL-BRAFV600E)]. The double transgenic mice (LNL-BRAFV600E;TPO-Cre) were derived from a high expressor line of Tg(LNLBRAFV600E) mice and TPO-Cre mice; the latter expresses Cre DNA recombinase under the control of thyroid-specific thyroid peroxidase (TPO) promoter and developed PTC-like lesions in early life under normal serum TSH levels due to mosaic recombination. In contrast, injection of adenovirus expressing Cre under the control of another thyroid-specific thyroglobulin (Tg) promoter (Ad-TgP-Cre) into the thyroids of LNL-BRAF V600E mice did not induce tumor formation despite detection ofBRAFV600EandpERKin a small fraction of thyroid cells. Second, postnatal expression ofBRAFV600E in a smallnumberof thyroid cellswasalso achieved by injecting the lentivirus expressing loxP-green fluorescent protein-loxP-BRAFV600E into the thyroids of TPO-Cre mice; however, no tumor development was again observed. These results suggest that BRAFV600E does not appear to induce PTC-like lesions when expressed in a fraction of thyroid cells postnatally under normal TSH concentrations

DHMEQ, a novel NF-kappaB inhibitor, suppresses growth and type I collagen accumulation in keloid fibroblasts

Background:Keloid is a benign dermal tumor characterized by proliferation of dermal fibroblasts and overproduction of extracellular matrix (ECM). Nuclear factor kappaB (NF-κB) plays an important role in regulation of inflammation, immune response and cell proliferation. Activation of the NF-κB pathway is thought to be closely linked to abnormal cell proliferation and ECM production in keloid fibroblasts. Objective:This study was set out to investigate the effects of a novel selective NF-κB inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ), on keloid fibroblasts. Methods:Primary normal and keloid dermal fibroblasts were used for this study. NF-κB activity was assessed by DNA-binding assay and immunohistochemistry. The effect of DHMEQ was evaluated by cell viability, cell growth and type I collagen accumulation. Results:Basal NF-κB activity was constitutively elevated in keloid fibroblasts, indicating that this pathway is involved in keloid pathogenesis. DHMEQ markedly reduced cell proliferation and type I collagen accumulation in keloid fibroblasts. Conclusion:The inhibition of NF-κB by DHMEQ may be an attractive therapeutic approach for keloids

Stem cell based regenerative medicine: is Russia taking the lead? A case study from St Petersburg

The recent scientific breakthroughs in genetics have lead to a thriving stem cell industry transforming the way medicine is practiced. This article discusses these developments and presents a case study of Russian research institute in St. Petersburg which is doing state of the art stem cell trials providing successful treatment of blood vessel disease and Ibone fractures. The potential impact of stem cell technology on regenerative medicine is discussed, the potential convergence of nanoparticle science and its contribution to stem cell research is discussed, and the dynamics of the stem cell industry is presente

The dynamics of the East African market

The establishment of the East African Community (EAC) Internal Market in 2010 creates a market of 126 million people. This article reviews the dynamics of marketing in the EAC by describing the history of the EAC formation, the socio-economic situation, and the role of factor investment in laying the foundation for rapid economic growth. Moreover the development of the retail environment in the EAC and the corresponding successful marketing mix strategies are described. The typical business strategy, structure, and rivalry and the role of chance are discussed as well as managerial implication for organizations entering or operating in the particular characteristics of the EAC marke

The dynamics of strategic capability

The strategic capability concept and its integration into the strategic planning process in international business have not been sufficiently explored as its conflicting definitions indicate. Moreover international managers may not be aware of the need for strategic capability because, the strategic capability paradigm for international business has not been sufficiently conceptualized and explored. Therefore this paper reviews how the business environment influences strategic capability, explains the elements of strategic capability, how strategic capability is integrated into the strategic planning, and gives some suggestions for future research on the strategic capability paradigm as it pertains to international businesse

Asian megatrends and management education of overseas Chinese

Asian megatrends are necessitating the development of management education of ethnic groups like the overseas Chinese and, universities need to change accordingly. This article identifies five Asian megatrends and their impact on the management education of overseas Chinese. The megatrends are: the emergence of women in politics and business; a shift in industrial strategy towards high technology; urbanization; the rise of consumerism; and migration of overseas Chinese back to China. Moreover two barriers to the impact the megatrends have on the management education of overseas Chinese are examined. Finally, a hypothetical model of the interrelationship of these variables is presente