BACKGROUND: In vitro cultures of neural stem cells have shown that estrogen can regulate beta-amyloid precursor protein (β-APP) metabolism and reduce amyloid-beta production. OBJECTIVE: To investigate the effects...BACKGROUND: In vitro cultures of neural stem cells have shown that estrogen can regulate beta-amyloid precursor protein (β-APP) metabolism and reduce amyloid-beta production. OBJECTIVE: To investigate the effects of long-term oral administration of compound nylestriol or low-dose 17beta-estradiol on β-APP and mRNA expression in the hippocampus of ovariectomized (OVX) rats. DESIGN, TIME AND SETTING: This randomized and controlled experiment was performed at the Animal Laboratory and Laboratory of Endocrine and Metabolic Disease, Xiangya Second Hospital of Central South University between April 2003 and May 2004. MATERIALS: According to body mass, 50 six-month-old female Sprague-Dawley rats were randomly divided into five groups (n = 10 per group): normal control, sham operation, OVX model, 17beta-estradiol (Sigma, USA), and compound nylestriol tablet (Laboratory of Endocrine and Metabolic Disease, Xiangya Second Hospital of Central South University) groups. METHODS: Rats in OVX plus 17beta-estradiol and OVX plus compound nylestriol tablet groups underwent ovariectomy. On the second day after surgery, rats were intragastrically given 17beta-estradiol (100 μg/kg), once per day or compound nylestriol tablet (0.5 mg/kg) and levonorgestrel (0.15 mg/kg) every 2 days. MAIN OUTCOME MEASURES: β-APP expression in the hippocampus of OVX rats was determined using immunohistochemistry (SABC method) and β-APP mRNA expression was analyzed by in situ hybridization. The results were quantitatively analyzed using cell counting and average optical density. RESULTS: The number and optical density of β-APP-positive neurons in every subregion of the hippocampus of OVX rats was dramatically increased compared with normal and sham operation groups following 35 weeks of administration (P 〈 0.05). Levels of β-APP were decreased following oral administration of compound nylestriol or 17beta-estradiol. In situ hybridization showed that long-term estrogen deficiency and oral administration of compound nylestriol or 17beta-estradiol did not alter the number of β-APP mRNA-positive neurons. CONCLUSION: The results show that long-term estrogen deficiency results in an increase of expression of β-APP though no changes in the expression of β-APP mRNA are detected. Replacement of estrogen with low-dose 17 beta-estradiol or compound nylestriol tablet inhibits the expression of β-APP in the hippocampus to the same extent.展开更多
Arsenic trioxide(ATO) is used as a chemotherapeutic agent for the treatment of acute promyelocytic leukemia. However, increasing drug resistance is reducing its efficacy. Therefore, a better understanding of ATO resis...Arsenic trioxide(ATO) is used as a chemotherapeutic agent for the treatment of acute promyelocytic leukemia. However, increasing drug resistance is reducing its efficacy. Therefore, a better understanding of ATO resistance mechanism is required. In this study, we established an ATO-resistant human epidermoid carcinoma cell line, KB/ATO, from its parental KB-3-1 cells. In addition to ATO, KB/ATO cells also exhibited cross-resistance to other anticancer drugs such as cisplatin, antimony potassium tartrate, and 6-mercaptopurine. The arsenic accumulation in KB/ATO cells was significantly lower than that in KB-3-1 cells. Further analysis indicated that neither application of P-glycoprotein inhibitor, breast cancer resistant protein(BCRP) inhibitor, or multidrug resistance protein 1(MRP1) inhibitor could eliminate ATO resistance. We found that the expression level of ABCB6 was increased in KB/ATO cells.In conclusion, ABCB6 could be an important factor for ATO resistance in KB/ATO cells. The ABCB6 level may serve as a predictive biomarker for the effectiveness of ATO therapy.展开更多
Estradiol (E2) is the major molecular form of estrogens. Its biological effects are determined by estrogen receptors and intracellular E2 concentration in target cells. Regulation of intracellular E2 concentration inv...Estradiol (E2) is the major molecular form of estrogens. Its biological effects are determined by estrogen receptors and intracellular E2 concentration in target cells. Regulation of intracellular E2 concentration involves the action of 17p-hydroxysteroid dehydrogenase (17HSD) type 2, the enzyme inactivating E2 to estrone. It has been demon-strated that 17HSD type 2 is expressed in normal endo-metrial epithelia and emdometrial carcinoma cells (RL 95-2). However, the regulatory mechanism of 17HSD type 2 expression in emdometrial cancer cells remains unknown. In the present study, the effects of transforming growth factor-β1 (TGF-β1) and epidermal growth factor (EGF) on 17HSD type 2 expression in RL 95-2 cells have been investigated using enzyme activity assay and Northern blot analysis. After stimulation with TGF-P1 or EGF, the in vivo oxidative 17HSD activity in RL 95-2 cells was significantly decreased. It appeared that the inhibitory effect of TGF-β1 and EGF onthe enzyme activity of 17HSD type 2展开更多
基金the National Key Medical Technologies Research and Development Program of China during the Tenth Five-Year Plan Period, No. 2001BA702B03
文摘BACKGROUND: In vitro cultures of neural stem cells have shown that estrogen can regulate beta-amyloid precursor protein (β-APP) metabolism and reduce amyloid-beta production. OBJECTIVE: To investigate the effects of long-term oral administration of compound nylestriol or low-dose 17beta-estradiol on β-APP and mRNA expression in the hippocampus of ovariectomized (OVX) rats. DESIGN, TIME AND SETTING: This randomized and controlled experiment was performed at the Animal Laboratory and Laboratory of Endocrine and Metabolic Disease, Xiangya Second Hospital of Central South University between April 2003 and May 2004. MATERIALS: According to body mass, 50 six-month-old female Sprague-Dawley rats were randomly divided into five groups (n = 10 per group): normal control, sham operation, OVX model, 17beta-estradiol (Sigma, USA), and compound nylestriol tablet (Laboratory of Endocrine and Metabolic Disease, Xiangya Second Hospital of Central South University) groups. METHODS: Rats in OVX plus 17beta-estradiol and OVX plus compound nylestriol tablet groups underwent ovariectomy. On the second day after surgery, rats were intragastrically given 17beta-estradiol (100 μg/kg), once per day or compound nylestriol tablet (0.5 mg/kg) and levonorgestrel (0.15 mg/kg) every 2 days. MAIN OUTCOME MEASURES: β-APP expression in the hippocampus of OVX rats was determined using immunohistochemistry (SABC method) and β-APP mRNA expression was analyzed by in situ hybridization. The results were quantitatively analyzed using cell counting and average optical density. RESULTS: The number and optical density of β-APP-positive neurons in every subregion of the hippocampus of OVX rats was dramatically increased compared with normal and sham operation groups following 35 weeks of administration (P 〈 0.05). Levels of β-APP were decreased following oral administration of compound nylestriol or 17beta-estradiol. In situ hybridization showed that long-term estrogen deficiency and oral administration of compound nylestriol or 17beta-estradiol did not alter the number of β-APP mRNA-positive neurons. CONCLUSION: The results show that long-term estrogen deficiency results in an increase of expression of β-APP though no changes in the expression of β-APP mRNA are detected. Replacement of estrogen with low-dose 17 beta-estradiol or compound nylestriol tablet inhibits the expression of β-APP in the hippocampus to the same extent.
基金supported by funds from NIH (No. 1R15CA143701)St. John's University Research Seed Grant (No. 579–1110-7002) to Zhe-Sheng Chen
文摘Arsenic trioxide(ATO) is used as a chemotherapeutic agent for the treatment of acute promyelocytic leukemia. However, increasing drug resistance is reducing its efficacy. Therefore, a better understanding of ATO resistance mechanism is required. In this study, we established an ATO-resistant human epidermoid carcinoma cell line, KB/ATO, from its parental KB-3-1 cells. In addition to ATO, KB/ATO cells also exhibited cross-resistance to other anticancer drugs such as cisplatin, antimony potassium tartrate, and 6-mercaptopurine. The arsenic accumulation in KB/ATO cells was significantly lower than that in KB-3-1 cells. Further analysis indicated that neither application of P-glycoprotein inhibitor, breast cancer resistant protein(BCRP) inhibitor, or multidrug resistance protein 1(MRP1) inhibitor could eliminate ATO resistance. We found that the expression level of ABCB6 was increased in KB/ATO cells.In conclusion, ABCB6 could be an important factor for ATO resistance in KB/ATO cells. The ABCB6 level may serve as a predictive biomarker for the effectiveness of ATO therapy.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 39700052).
文摘Estradiol (E2) is the major molecular form of estrogens. Its biological effects are determined by estrogen receptors and intracellular E2 concentration in target cells. Regulation of intracellular E2 concentration involves the action of 17p-hydroxysteroid dehydrogenase (17HSD) type 2, the enzyme inactivating E2 to estrone. It has been demon-strated that 17HSD type 2 is expressed in normal endo-metrial epithelia and emdometrial carcinoma cells (RL 95-2). However, the regulatory mechanism of 17HSD type 2 expression in emdometrial cancer cells remains unknown. In the present study, the effects of transforming growth factor-β1 (TGF-β1) and epidermal growth factor (EGF) on 17HSD type 2 expression in RL 95-2 cells have been investigated using enzyme activity assay and Northern blot analysis. After stimulation with TGF-P1 or EGF, the in vivo oxidative 17HSD activity in RL 95-2 cells was significantly decreased. It appeared that the inhibitory effect of TGF-β1 and EGF onthe enzyme activity of 17HSD type 2