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Shanle E.K.,University of Wisconsin - Madison | Onitilo A.A.,Marshfield Clinic Weston Center | Huang W.,University of Wisconsin - Madison | Kim K.M.,University of Wisconsin - Madison | And 4 more authors.
American Journal of Translational Research | Year: 2015

Triple negative breast cancer (TNBC) is an aggressive breast cancer subtype for which there is a need to identify new therapeutic targets. Full-length estrogen receptor beta (ERβ1) may be a possible target given its antiproliferative effects on breast cancer cells. The prognostic significance of ERβ in breast cancer subtypes has remained elusive, and disparate results observed across previously published reports might be due to the detection of multiple ERβ isoforms, the lack of specific antibodies and the use of different cutoffs to define ERβpositivity. The objective of this retrospective study was to determine the association between ERβ1 expression and disease-free and overall survival, as well as Ki67 expression, in non-metastatic TNBC. Immunohistochemical protocols were optimized using xenograft tissues obtained from a breast cancer cell line with inducible ERβ1 expression. ERβ1 localization and expression were assessed in two cohorts of TNBC using the VECTRATM platform. There was a close relationship between nuclear and cytoplasmic ERβ1 expression. ERβ1 was expressed in a subset of TNBCs, but its expression was significantly associated with Ki67 in only one of the cohorts. There was no significant association between ERβ1 expression and disease-free and overall survival in either cohort. Although these results suggest that ERβ1 expression alone may not be informative in TNBCs, this study provides a new strategy for optimizing and objectively measuring ERβ1 expression in tissues, which may provide a standard for ERβ1 immunohistochemistry in future large-scale clinical studies aimed at better understanding the role of ERβ1 in breast cancer. © 2015, E-Century Publishing Corporation. All rights reserved.


Khan N.,University of Wisconsin - Madison | Afaq F.,University of Wisconsin - Madison | Afaq F.,University of Alabama at Birmingham | Khusro F.H.,University of Wisconsin - Madison | And 4 more authors.
International Journal of Cancer | Year: 2012

Lung cancer is one of the most commonly occurring malignancies. It has been reported that mammalian target of rapamycin (mTOR) is phosphorylated in lung cancer and its activation was more frequent in tumors with overexpression of phosphatidylinositol 3-kinase (PI3K)/Akt. Therefore, dual inhibitors of PI3K/Akt and mTOR signaling could be valuable agents for treating lung cancer. In the present study, we show that fisetin, a dietary tetrahydroxyflavone inhibits cell growth with the concomitant suppression of PI3K/Akt and mTOR signaling in human nonsmall cell lung cancer (NSCLC) cells. Using autodock 4, we found that fisetin physically interacts with the mTOR complex at two sites. Fisetin treatment was also found to reduce the formation of A549 cell colonies in a dose-dependent manner. Treatment of cells with fisetin caused decrease in the protein expression of PI3K (p85 and p110), inhibition of phosphorylation of Akt, mTOR, p70S6K1, eIF-4E and 4E-BP1. Fisetin-treated cells also exhibited dose-dependent inhibition of the constituents of mTOR signaling complex such as Rictor, Raptor, GβL and PRAS40. There was an increase in the phosphorylation of AMPKα and a decrease in the phosphorylation of TSC2 on treatment of cells with fisetin. We also found that treatment of cells with mTOR inhibitor rapamycin and mTOR-siRNA caused decrease in phosphorylation of mTOR and its target proteins which were further downregulated on treatment with fisetin, suggesting that these effects are mediated in part, through mTOR signaling. Our results show that fisetin suppressed PI3K/Akt and mTOR signaling in NSCLC cells and thus, could be developed as a chemotherapeutic agent against human lung cancer. Copyright © 2011 UICC.


Goodman C.A.,University of Wisconsin - Madison | McNally R.M.,University of Wisconsin - Madison | Hoffmann F.M.,McArdle Laboratory for Cancer Research | Hoffmann F.M.,University of Wisconsin - Madison | Hornberger T.A.,University of Wisconsin - Madison
Molecular Endocrinology | Year: 2013

Myostatin, a member of the TGF superfamily, is sufficient to induce skeletal muscle atrophy. Myostatin-induced atrophy is associated with increases in E3-ligase atrogin-1 expression and protein degradation and decreases in Akt/mechanistic target of rapamycin (mTOR) signaling and protein synthesis. Myostatin signaling activates the transcription factor Smad3 (Small Mothers Against Decapentaplegic), which has been shown to be necessary for myostatin-induced atrogin-1 expression and atrophy; however, it is not known whether Smad3 is sufficient to induce these events or whether Smad3 simply plays a permissive role. Thus, the aim of this study was to address these questions with an in vivo model. To accomplish this goal, in vivo transfection of plasmid DNA was used to create transient transgenic mouse skeletal muscles, and our results show for the first time that Smad3 expression is sufficient to stimulate atrogin-1 promoter activity, inhibit Akt/ mTOR signaling and protein synthesis, and induce muscle fiber atrophy. Moreover, we propose that Akt/mTOR signaling is inhibited by a Smad3-induced decrease in microRNA-29 (miR-29) expression and a subsequent increase in the translation of phosphatase and tensin homolog (PTEN) mRNA. Smad3 is also sufficient to inhibit peroxisome proliferator-activated receptorcoactivator-γ coactivator-1α (PGC1α) promoter activity and to increase FoxO (Forkhead Box Protein, Subclass O)-mediated signaling and the promoter activity of plasminogen activator inhibitor 1 (PAI-1). Combined, this study provides the first evidence that Smad3 is sufficient to regulate many of the events associated with myostatin-induced atrophy and therefore suggests that Smad3 signaling may be a viable target for therapies aimed at preventing myostatin-induced muscle atrophy. © 2013 by The Endocrine Society.


Maufort J.P.,McArdle Laboratory for Cancer Research | Shai A.,McArdle Laboratory for Cancer Research | Shai A.,University of California at San Francisco | Pitot H.C.,McArdle Laboratory for Cancer Research | And 2 more authors.
Cancer Research | Year: 2010

A subset of the mucosotropic human papillomaviruses (HPV), including HPV16, are etiologic agents for the vast majority of cervical cancers, other anogenital cancers, and a subset of head and neck squamous cell carcinomas. HPV16 encodes three oncogenes: E5, E6, and E7. Although E6 and E7 have been well-studied and clearly shown to be important contributors to these cancers, less is known about E5. In this study, we used E5 transgenic mice to investigate the role of E5 in cervical cancer. When treated for 6 months with estrogen, a cofactor for cervical carcinogenesis, E5 transgenic mice developed more severe neoplastic cervical disease than similarly treated nontransgenic mice, although no frank cancers were detected. In addition, E5 when combined with either E6 or E7 induced more severe neoplastic disease than seen in mice expressing only one viral oncogene. Prolonged treatment of E5 transgenic mice with exogenous estrogen uncovered an ability of E5 to cause frank cancer. These data indicate that E5 acts as an oncogene in the reproductive tracts of female mice. © 2010 American Association for Cancer Research.


Clipson L.,McArdle Laboratory for Cancer Research | Hasenstein J.R.,McArdle Laboratory for Cancer Research | Alexander C.M.,McArdle Laboratory for Cancer Research | Dove W.F.,McArdle Laboratory for Cancer Research | And 2 more authors.
G3: Genes, Genomes, Genetics | Year: 2012

The gene-trap lacZ reporter insertion, ROSA11, in the Cbx5 mouse gene illuminates the regulatory complexity of this locus in ApcMin/+ mice. The insertion site of the b-Geo gene-trap element lies in the 24-kb intron proximal to the coding region of Cbx5. Transcript analysis indicates that two promoters for Cbx5 flank this insertion site. Heterozygotes for the insertion express lacZ widely in fetal tissues but show limited expression in adult tissues. In the intestine, strong expression is limited to proliferative zones of crypts and tumors. Homozygotes for ROSA11, found at a lower than Mendelian frequency, express reduced levels of the coding region transcript in normal tissues, using a downstream promoter. Analysis via real-time polymerase chain reaction indicates that the upstream promoter is the dominant promoter in normal epithelium and tumors. Bioinformatic analysis of the Cbx5 locus indicates that WNT and its target transcription factor MYC can establish a feedback loop that may play a role in regulating the self-renewal of the normal intestinal epithelium and its tumors. ©2012 Thliveris et al.

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