A new polybrominated diphenyl ether ( 9), together with eight known compounds, were isolated from the crude organic extract of the marine sponge Dysidea sp. collected from the Federated States of Micronesia. Their structures were elucidated on the basis of various NMR spectroscopic data. These compounds exhibited inhibitory activities against Streptomyces 85E in the hyphae formation inhibition (HFI) assay and displayed antiproliferative activities against the human breast adenocarcinoma cancer cell line MCF-7. Compound 6 was selected for further evaluation in a cell cycle progression study.

A new bromotyrosine-derived alkaloid, (+)-aplysinillin (1), together with seven known compounds, was isolated from the crude organic extract of the marine sponge Aplysinella sp. collected from the Federated States of Micronesia. The structure of 1 was deduced by NMR and mass spectral techniques. Compounds 1-8 were evaluated for their inhibitory activity with the hyphae formation inhibition assay in Streptomyces 85E. Compounds 1 and 8 exhibited antiproliferative activities against the human breast adenocarcinoma cancer cell line MCF-7.

NOP16, also known as HSPC111, has been identified as a MYC and estrogen regulated gene in in vitro studies, hence coexpression levels were strongly correlated. Importantly, high expression of NOP16 was associated with poor clinical outcome in breast cancer patients. However, coexpression of NOP16, MYC and estrogen receptor (ESR1) varied widely in tumors and cell lines suggesting that transcriptional regulation differed according to pathological environments. The goal of this study was to determine the expression patterns of Nop16, Myc and Esr1 in murine mammary tumors with disparate histopathological and molecular features. We hypothesized that tumor environments with relatively high Myc levels would have different coexpression patterns than tumor environments with relatively low Myc levels. We measured levels of Myc and Nop16 mRNA and protein in tumors from WAP-c-myc mice that were of high grade and metastasized frequently. In contrast, Myc and Nop16 mRNA and proteins levels were significantly lower in the less aggressive tumors that developed in NRL-TGFα mice. Tumors from both mouse lines express ESR1 protein and we found that Esr1 mRNA levels correlated positively with Myc levels in both models. However, Myc and Nop16 transcript levels correlated positively only in tumors from NRL-TGFα mice. We identified prominent NOP16 protein in nuclei and less prominent staining in the cytoplasm of luminal cells of ducts and lobules from normal mammary glands as well as in hyperplasias and tumors obtained from NRL-TGFα mice. This staining pattern was reversed in tumors from WAP-c-Myc mice as nuclear staining was faint or absent and cytoplasmic staining more pronounced. In summary, the regulation of expression and localization of NOP16 varies in tumor environments with high versus low MYC levels and demonstrate the importance of stratifying clinical breast cancers based on MYC levels.

As part of an upper level undergraduate developmental biology course at the University of Minnesota Duluth, we developed a unit in which students carried out original research as part of a cooperative class project. Students had the opportunity to gain experience in the scientific method from experimental design all of the way through to the preparation of publication on their research that included text, figures, and tables. This kind of inquiry-based learning has been shown to have many benefits for students, including increased long-term learning and a better understanding of the process of scientific discovery. In our project, students designed experiments to explore why zebrafish typically spawn in the first few hours after the lights come on in the morning. The results of our experiments suggest that spawning still occurs when the dark-to-light transition is altered or absent. This is consistent with the work of others that demonstrates that rhythmic spawning behavior is regulated by an endogenous circadian clock. Our successes and failures carrying out original research as part of an undergraduate course should contribute to the growing approaches for using zebrafish to bring the excitement of experimental science to the classroom.

We previously reported that TGFα transgenic mice which received a 60-day course of tamoxifen chemoprevention had a reduced incidence of estrogen receptor positive mammary tumors by ∼50%. Mammary gene expression analysis several weeks post-tamoxifen but months prior to tumor development revealed reduced mRNA levels of the developmental gene, Elf5, in mice that remained tumor free throughout life compared to those that developed tumors. Elf5 belongs to the Elf group of transcription factors, which have ascribed roles in epithelial cell organization during organogenesis and make up a subfamily of the Ets family of transcription factors, some of which have been implicated in cancer. ELF5 is a downstream effector molecule of prolactin and instrumental to lobular development during pregnancy. Other laboratories have reported that Elf5 mRNA expression is highest in mammary epithelial cell isolates enriched with luminal progenitor cells, a subpopulation that has been shown to be increased in some murine models of mammary cancer as well as in breast tissue isolated from women with BRCA1 mutations. These data implicate luminal progenitor cells as tumor forming cells and Elf5 as a participant in cancer development. In this study, our goals were to determine (1) if there were alterations in the proportions of mammary epithelial subpopulations in glands from TGFα mice using flow cytometry and (2) the presence and pattern of ELF5 protein expression in clinical breast biopsies and in mammary glands isolated from TGFα and c-myc mammary cancer prone mice using immunohistochemistry. We found that glands from TGFα mice had an increased fraction of luminal progenitor cells compared with wild type mice which coincided with increased Elf5 mRNA expression. We then identified ELF5 protein in the nuclei of luminal cells in ducts and lobules and in higher proportions within hyperplasias from glands of both TGFα and c-myc transgenic mice. Tumor epithelia from low-grade and highgrade tumors from TGFα and c-myc, respectively, displayed negligible ELF5 protein, while surrounding reactive stroma contained spindle-like cells and endothelial cells displayed intense ELF5 staining. In an initial screen of 25 human breast biopsies ELF5 protein localization was similar to that found in mice, with nuclear ELF5 expressed in a subset of luminal cells of normal ducts and lobules and in hyperplasias but not in in situ carcinomas. ELF5 protein was frequently found in the epithelial cells of high-grade tumors but infrequently observed in low-grade tumors. In a second screen of strictly high-grade cancers (≥Grade 3) ELF5 staining was found in the epithelial compartment in ∼75% of the cases, but expression was predominantly cytoplasmic. Similar to findings in mouse models, immunolocalization of ELF5 in human breast samples was not restricted to the epithelial compartment but included spindle-shaped cells and endothelial cells within the reactive stroma of all tumors, regardless of tumor epithelial ELF5 staining status. These novel data indicate that ELF5 may contribute to breast carcinogenesis in both humans and mice. The data also demonstrate that ELF5 expression is not restricted to epithelia and points to a role of this transcription factor in the tumor reactive stromal microenvironment. Citation Information: Cancer Prev Res 2010;3(12 Suppl):A7.