Progesterone receptor antagonists reverse stem cell expansion and the paracrine effectors of progesterone action in the mouse mammary gland.

BACKGROUND: The ovarian hormones estrogen and progesterone (EP) are implicated in breast cancer causation. A specific consequence of progesterone exposure is the expansion of the mammary stem cell (MSC) and luminal progenitor (LP) compartments. We hypothesized that this effect, and its molecular facilitators, could be abrogated by progesterone receptor (PR) antagonists administered in a mouse model. METHODS: Ovariectomized FVB mice were randomized to 14 days of treatment: sham, EP, EP + telapristone (EP + TPA), EP + mifepristone (EP + MFP). Mice were then sacrificed, mammary glands harvested, and mammary epithelial cell lineages separated by flow cytometry using cell surface markers. RNA from each lineage was sequenced and differential gene expression was analyzed using DESeq. Quantitative PCR was performed to confirm the candidate genes discovered in RNA seq. ANOVA with Tukey post hoc analysis was performed to compare relative expression. Alternative splicing events were examined using the rMATs multivariate analysis tool. RESULTS: Significant increases in the MSC and luminal mature (LM) cell fractions were observed following EP treatment compared to control (p < 0.01 and p < 0.05, respectively), whereas the LP fraction was significantly reduced (p < 0.05). These hormone-induced effects were reversed upon exposure to TPA and MFP (p < 0.01 for both). Gene Ontology analysis of RNA-sequencing data showed EP-induced enrichment of several pathways, with the largest effect on Wnt signaling in MSC, significantly repressed by PR inhibitors. In LP cells, significant induction of Wnt4 and Rankl, and Wnt pathway intermediates Lrp2 and Axin2 (confirmed by qRTPCR) were reversed by TPA and MFP (p < 0.0001). Downstream signaling intermediates of these pathways (Lrp5, Mmp7) showed similar effects. Expression of markers of epithelial-mesenchymal transition (Cdh1, Cdh3) and the induction of EMT regulators (Zeb1, Zeb2, Gli3, Snai1, and Ptch2) were significantly responsive to progesterone. EP treatment was associated with large-scale alternative splicing events, with an enrichment of motifs associated with Srsf, Esrp, and Rbfox families. Exon skipping was observed in Cdh1, Enah, and Brd4. CONCLUSIONS: PR inhibition reverses known tumorigenic pathways in the mammary gland and suppresses a previously unknown effect of progesterone on RNA splicing events. In total, our results strengthen the case for reconsideration of PR inhibitors for breast cancer prevention.

Lower Back Pain Imaging: A Readability Analysis.

PURPOSE: The internet provides access to a myriad of educational health-related resources which are an invaluable source of information for patients. Lower back pain is a common complaint that is discussed extensively online. In this article, we aim to determine if the most commonly accessed articles about lower back pain imaging use language that can be understood by most patients. According to the American Medical Association (AMA) and National Institute of Health (NIH), this corresponds to a sixth-grade reading level. METHODS: Online searches were conducted from the most commonly used search engine, Google, to assess the present state of readability on radiograph imaging for LBP. Then the top 20 populated URL links from each search were utilized based on "health & fitness" search trends and click-through rates (CTRs). The readability of various websites was evaluated with WebFX online software that analyzed the unique websites' text when put into reader view on Firefox web browser version 116.0.3 (64-bit). Evaluation occurred via five common readability indices: the Automated Readability Index (ARI), the Coleman Liau Index (CLI), the SMOG index, the Gunning Fog Score Index (GFSI), and the Flesch Kincaid Grade Level Index (FKGLI). In addition, the Flesch Kincaid Reading Ease Index (FKREI) was also used but was excluded from the calculation due to its measuring scale outside of US grade levels. The number of samples was analyzed via health and fitness-specific CTR from an open-access database from July 2022 to July 2023. This was used to calculate the number of persons clicking and visiting positional URLs (first URL to the 20th URL) from each unique keyword search and the rational criteria for selecting the first 20 websites for each query. RESULTS: Online material that included LBP imaging information was calculated to have an overall readability score of 10.745 out of the 23 websites obtained from unique searches. The range was a mean readability score of 8 to 14. Notably, 17 websites were excluded from a total of 40 websites due to duplication of the same data (URLs that resulted from both unique searches) and accessibility requiring payment (specifically, an UpToDate link). A readability score of 10.745 refers to an 11th-grade reading level. That is to say, the most commonly visited sites on Google that contain information about lower back pain imaging are, on average, five grade levels higher than the sixth-grade reading level recommended by the AMA and the NIH. CONCLUSIONS: Most internet content regarding lower back pain imaging is written at a reading level that is above the recommended limit defined by the AMA and NIH. To improve education about lower back pain imaging and the patient-physician relationship, we recommend guiding patients to online material that contains a reading level at the sixth-grade level as suggested by the AMA and NIH.

Lipid exposure activates gene expression changes associated with estrogen receptor negative breast cancer.

Improved understanding of local breast biology that favors the development of estrogen receptor negative (ER-) breast cancer (BC) would foster better prevention strategies. We have previously shown that overexpression of specific lipid metabolism genes is associated with the development of ER- BC. We now report results of exposure of MCF-10A and MCF-12A cells, and mammary organoids to representative medium- and long-chain polyunsaturated fatty acids. This exposure caused a dynamic and profound change in gene expression, accompanied by changes in chromatin packing density, chromatin accessibility, and histone posttranslational modifications (PTMs). We identified 38 metabolic reactions that showed significantly increased activity, including reactions related to one-carbon metabolism. Among these reactions are those that produce S-adenosyl-L-methionine for histone PTMs. Utilizing both an in-vitro model and samples from women at high risk for ER- BC, we show that lipid exposure engenders gene expression, signaling pathway activation, and histone marks associated with the development of ER- BC.

Character displacement in the midst of background evolution in island populations of Anolis lizards: A spatiotemporal perspective.

Negative interactions between species can generate divergent selection that causes character displacement. However, other processes cause similar divergence. We use spatial and temporal replication across island populations of Anolis lizards to assess the importance of negative interactions in driving trait shifts. Previous work showed that the establishment of Anolis sagrei on islands drove resident Anolis carolinensis to perch higher and evolve larger toepads. To further test the interaction's causality and predictability, we resurveyed a subset of islands nine years later. Anolis sagrei had established on one island between surveys. We found that A. carolinensis on this island now perch higher and have larger toepads. However, toepad morphology change on this island was not distinct from shifts on six other islands whose Anolis community composition had not changed. Thus, the presence of A. sagrei only partly explains A. carolinensis trait variation across space and time. We also found that A. carolinensis on islands with previously established A. sagrei now perch higher than a decade ago, and that current A. carolinensis perch height is correlated with A. sagrei density. Our results suggest that character displacement likely interacts with other evolutionary processes in this system, and that temporal data are key to detecting such interactions.