Our previous studies demonstrated that 17␤-estradiol (E2) rapidly induces the interaction of estrogen receptor ␣ (ER␣) with the adapter protein Shc, the translocation of ER␣ to the cell membrane, and the formation of dynamic membrane structures in MCF-7 breast cancer cells. The present study examined how E2 causes ER␣ to translocate to the region of the plasma membrane and focused on mechanisms whereby Shc and the insulin-like growth factor-1 receptor (IGF-1R) mediate this process. Shc physically interacts with IGF-1R in the plasma membrane, and E2 activates IGF-1R. We reasoned that ER␣, when bound to Shc, would be directed to the region of the plasma membrane by the same processes, causing membrane translocation of Shc. We confirmed that E2 rapidly induced IGF-1R phosphorylation and demonstrated that E2 induced formation of a ternary protein complex among Shc, ER␣, and IGF-1R. Knock down of Shc with a specific small inhibitory RNA decreased the association of ER␣ with IGF-1R by 87%, suggesting that Shc is a crucial molecule in the formation of this ternary complex. Confocal microscopy studies provided further confirmation of the functional roles of Shc and the IGF-1R in the translocation of ER␣ to the region of the membrane. Down-regulation of Shc, ER␣, or IGF-1R with specific small inhibitory RNAs all blocked E2-induced mitogen-activated protein kinase phosphorylation. Together, our results demonstrate that Shc and IGF-1R serve as key elements in the translocation of ER␣ to the cell membrane and in the facilitation of ER␣-mediated rapid E2 action.

KLF5 is a transcription factor that plays important roles in multiple physical and pathological processes, including cell growth, cell cycle regulation, and angiogenesis. To better characterize KLF5 function in bladder carcinogenesis, we established stable TSU-Pr1 cell clones expressing different levels of KLF5. These clones were then characterized for cell growth, cell cycle progression, tumorigenesis, and alteration in gene expression. Overexpression of KLF5 promoted tumorigenesis of the TSU-Pr1 cancer cells in mice. Consistently, KLF5 increased G1 to S phase transition, which was accompanied by the upregulation of cyclin D1, phosphorylation of MAPK and Akt, and reduced protein levels for CDK inhibitors p27 and p15. Microarray analysis combined with expression verification in different cell systems identified a number of additional genes that are potentially regulated by KLF5, including HBP17, ITGA6, and RAIG1. These findings suggest that the KLF5 transcription factor plays an oncogenic role in the TSU-Pr1 bladder cancer cell line through the regulation of a subset of genes. ' 2005 Wiley-Liss, Inc.

This study’s aim was to assess the histological and metabolic effects of N-3 polyunsaturated fatty acids (PUFA) versus placebo while adjusting for the impact of age and weight change in NASH patients. (ClinicalTrials.gov: NCT00681408). Methods Forty-one subjects with non-cirrhotic NASH were enrolled, and 34 completed the study. 17 received N-3 fish oil 3000 mg/day and 17 received placebo daily for 1 year with typical counseling on caloric intake and physical activity for all subjects. Results N-3- and placebo-treated groups showed no significant difference for the primary endpoint of NAS reduction ≥ 2 points without fibrosis progression after adjustment for known covariates (N-3, 4/17 (23.5%); placebo, 3/17, (17.6%), p=0.99). Among subjects with increased or stable weight, N-3 subjects showed a larger decrease in liver fat content by MRI than placebo-treated subjects (p=0.014 for 2nd quartile, p=0.003 for 3rd quartile of weight change). N-3 treatment showed significant fat reduction on paired analysis of image-assisted fat morphometry regardless of weight loss or gain. Exercise capacity remained markedly reduced in all subjects. No independent effects on markers of hepatocyte injury or insulin sensitivity indices were observed. Conclusion N-3 PUFA at 3000 mg/day for one year did not lead to improvement in the primary outcome of histological activity in NASH patients (≥ 2 point NAS reduction). N-3 led to reduced liver fat by multiple measures. Other metabolic effects were not seen, although no detrimental effects were apparent. Whether longer duration, higher dose, or different composition of N-3 therapy would lead to additional benefit is uncertain.

E2 rapidly activates MAPK in breast cancer cells, and the mechanism for this effect has not been fully identified. Since growth factor-induced MAPK activation involves signaling via the adapter protein Shc (Src-homology and collagen homology) and its association with membrane receptors, we hypothesized that breast cancer cells utilize similar signaling mechanisms in response to E2. In the present study, we demonstrated that E2 rapidly induced Shc phosphorylation and Shc-Grb2 (growth factor receptor binding protein 2)-Sos (son of sevenless) complex formation in MCF-7 cells. Overexpression of dominant negative Shc blocked the effect of E2 on MAPK, indicating a critical role of Shc in E2 action. Using selective inhibitors, we also demonstrated that ERalpha and Src are upstream regulators of Shc. A rapid physical association between ERalpha and Shc upon E2 stimulation further evidenced the role of ERalpha on Shc activation. Mutagenesis studies showed that the phosphotyrosine binding and SH2 domains of Shc are required to interact with the activation function 1, but not activation function 2, domain of ERalpha. Using a glutathione-S-transferase-Shc pull-down assay, we demonstrated that this ERalpha-Shc association was direct. Biological consequences of this pathway were further investigated at the genomic and nongenomic levels. E2 stimulated MAPK-mediated Elk-1 transcriptional activity. Confocal microscopy studies showed that E2 rapidly induced formation of membrane ruffles, pseudopodia, and ERalpha membrane translocation. The E2-induced morphological changes were prevented by antiestrogen. Together our results demonstrate that ERalpha can mediate the rapid effects of E2 on Shc, MAPK, Elk-1, and morphological changes in breast cancer cells