<p>2-Methoxyestradiol (2-ME), a metabolite of 17β-estradiol, is a potent antitumor and antiangiogenesis agent in vitro and in vivo. This study aimed to investigate the effects of 2-ME on human cervical and endometrial cancers in vitro and in vivo. Human cervical cancer HeLaS3 cells, endometrial cancer HEC-1-A and RL-95-2 cells, and severe combined immune deficient (SCID) mice were used. On cervical cancer HeLaS3 cells, 2-ME inhibited the cell growth which is accompanied by apoptosis via iNOS pathway and by G₂/M cell cycle arrest. 2-ME had slight effects on normal cervical epithelial cells. In vivo on SCID mice, 2-ME (75 mg/kg p.o.) inhibited the growth of human cervical carcinoma by 34% (p < 0.05) and showed slight side effects to liver and spleen. On human endometrial cancer cells (HEC-1-A and RL-95-2 cells), 2-ME inhibited the growth by blocking cell cycle progress in S- and G₂/M-phase in both cell types, and by inducing apoptosis in HEC-1-A cells and by causing necrosis in RL-95-2 cells. 2-ME had no effects on normal endometrial cells. The apoptotic effect, in HEC-1-A cells, was prevented by iNOS-inhibitor 1400W and eliminated by Caspase-inhibitor Z-VAD-FMK. The necrosis, on RL-95-2 cells, was due to a severe disruption of the mitochondrial membrane potential. Unfortunately, 2-ME had no significant effects on endometrial cancer xenografts. It showed slight toxicity to liver, spleen and proliferative effect on uterus. In conclusion, 2-ME inhibits the growth of human cervical and endometrial cancer cells in vitro. However, a weaker anti-tumor effect was observed in our animal model and 2-ME was slightly toxic to liver and spleen. Considering the proliferative effect on uterus, 2-ME might not be a suitable therapeutic agent in gynecological tumors.</p>

<p>Molecular mechanisms in the development and progression of thyroid carcinomas are still not fully understood. In the present thesis the highly malignant anaplastic thyroid carcinoma (ATC) was used to study regulation of apoptosis and tumor interstitial fluid pressure (IFP).</p><p>Addition of a natural estrogen metabolite, 2-Methoxyestradiol (2-ME), induced a G2/M cell cycle arrest and apoptosis in five out of six human ATC cell lines. Treatment with 2-ME induced DNA-fragmentation as well as activation of caspase-3. Inhibitors of JNK and p38 MAPKs activity decreased the effect of 2-ME suggesting involvement in the induction of apoptosis.</p><p>Solid tumors have an elevated IFP. High IFP forms or reflects a barrier for exchange of molecules between microvessels and surrounding tissue. The mechanisms for the generation of the high IFP were investigated using a specific TGF-β inhibitor in an ATC model in athymic mice. Tumor IFP was lowered in TGF-β inhibitor-treated compared to control mice. Affymetrix microarray analysis showed a decreased expression of macrophage-associated genes in treated tumors. Furthermore, the number and activity of tumor-associated macrophages was reduced after TGF-β inhibition. A decreased protein leakage together with an increased coverage of α-smooth-muscle actin (SMA)-expressing cells indicated vessel normalization. An adjuvant treatment with the TGF-β inhibitor resulted in an increased treatment efficacy of doxorubicin. Thus, TGF-β inhibitor-treatment suggests improved microvessel function which results in a lowering of tumor IFP and increased tumor drug uptake.</p><p>To create a model for specific inactivation of genes in the thyroid, a transgenic mouse with a thyrocyte-specific expression of Cre recombinase was generated. The thyroglobulin promoter together with an inducible Cre recombinase (<i>creER</i><i>T2</i>) was used. Two transgenic founder lines were identified expressing cre mRNA solely in the thyroid. Functional activity of the CreER^T2 protein was demonstrated by using a ROSA26-LacZ reporter mouse.</p>

Molecular mechanisms in the development and progression of thyroid carcinomas are still not fully understood. In the present thesis the highly malignant anaplastic thyroid carcinoma (ATC) was used to study regulation of apoptosis and tumor interstitial fluid pressure (IFP). Addition of a natural estrogen metabolite, 2-Methoxyestradiol (2-ME), induced a G2/M cell cycle arrest and apoptosis in five out of six human ATC cell lines. Treatment with 2-ME induced DNA-fragmentation as well as activation of caspase-3. Inhibitors of JNK and p38 MAPKs activity decreased the effect of 2-ME suggesting involvement in the induction of apoptosis. Solid tumors have an elevated IFP. High IFP forms or reflects a barrier for exchange of molecules between microvessels and surrounding tissue. The mechanisms for the generation of the high IFP were investigated using a specific TGF-β inhibitor in an ATC model in athymic mice. Tumor IFP was lowered in TGF-β inhibitor-treated compared to control mice. Affymetrix microarray analysis showed a decreased expression of macrophage-associated genes in treated tumors. Furthermore, the number and activity of tumor-associated macrophages was reduced after TGF-β inhibition. A decreased protein leakage together with an increased coverage of α-smooth-muscle actin (SMA)-expressing cells indicated vessel normalization. An adjuvant treatment with the TGF-β inhibitor resulted in an increased treatment efficacy of doxorubicin. Thus, TGF-β inhibitor-treatment suggests improved microvessel function which results in a lowering of tumor IFP and increased tumor drug uptake. To create a model for specific inactivation of genes in the thyroid, a transgenic mouse with a thyrocyte-specific expression of Cre recombinase was generated. The thyroglobulin promoter together with an inducible Cre recombinase (creERT2) was used. Two transgenic founder lines were identified expressing cre mRNA solely in the thyroid. Functional activity of the CreERT2 protein was demonstrated by using a ROSA26-LacZ reporter mouse.

2-Methoxyestradiol (2-ME), a metabolite of 17β-estradiol, is a potent antitumor and antiangiogenesis agent in vitro and in vivo. This study aimed to investigate the effects of 2-ME on human cervical and endometrial cancers in vitro and in vivo. Human cervical cancer HeLaS3 cells, endometrial cancer HEC-1-A and RL-95-2 cells, and severe combined immune deficient (SCID) mice were used. On cervical cancer HeLaS3 cells, 2-ME inhibited the cell growth which is accompanied by apoptosis via iNOS pathway and by G2/M cell cycle arrest. 2-ME had slight effects on normal cervical epithelial cells. In vivo on SCID mice, 2-ME (75 mg/kg p.o.) inhibited the growth of human cervical carcinoma by 34% (p &lt; 0.05) and showed slight side effects to liver and spleen. On human endometrial cancer cells (HEC-1-A and RL-95-2 cells), 2-ME inhibited the growth by blocking cell cycle progress in S- and G2/M-phase in both cell types, and by inducing apoptosis in HEC-1-A cells and by causing necrosis in RL-95-2 cells. 2-ME had no effects on normal endometrial cells. The apoptotic effect, in HEC-1-A cells, was prevented by iNOS-inhibitor 1400W and eliminated by Caspase-inhibitor Z-VAD-FMK. The necrosis, on RL-95-2 cells, was due to a severe disruption of the mitochondrial membrane potential. Unfortunately, 2-ME had no significant effects on endometrial cancer xenografts. It showed slight toxicity to liver, spleen and proliferative effect on uterus. In conclusion, 2-ME inhibits the growth of human cervical and endometrial cancer cells in vitro. However, a weaker anti-tumor effect was observed in our animal model and 2-ME was slightly toxic to liver and spleen. Considering the proliferative effect on uterus, 2-ME might not be a suitable therapeutic agent in gynecological tumors.