LABORATORY RESEARCH Circadian and Melatonin Disruption by Exposure to Light at Night Drives Intrinsic Resistance to Tamoxifen Therapy in Breast Cancer Light exposure at night (LEN) suppresses the nocturnal production of melatonin that inhibits breast cancer growth. Researchers used a rat model of estrogen receptor MCF-7 tumor xenografts to demonstrate how altering light/dark cycles with dim LEN speed the development of breast tumors, increasing their metabolism and growth and conferring an intrinsic resistance to tamoxifen therapy. [Cancer Res] Abstract | Press Release Nodal Signaling Promotes a Tumorigenic Phenotype in Human Breast Cancer Scientists demonstrate that Nodal is required in aggressive human breast cancer cells to activate ERK signaling and downstream tumorigenic phenotypes both in vitro and in vivo. [Semin Cancer Biol] Abstract TRIM24 Links Glucose Metabolism with Transformation of Human Mammary Epithelial Cells Scientists used an isogenic human mammary epithelial cell (HMEC) culture model, derived from reduction mammoplasty tissue, and report that ectopic expression of tripartite motif 24 protein (TRIM24) in immortalized HMECs greatly increased cellular proliferation and induced malignant transformation. [Oncogene] Abstract miR-7, Inhibited Indirectly by LincRNA HOTAIR, Directly Inhibits SETDB1 and Reverses the EMT of Breast Cancer Stem Cells by Downregulating the STAT3 Pathway Researchers showed that miR-7, which was downregulated in breast cancer stem cells (BCSCs) isolated from the human MCF-7 and MDA-MB-231 cell lines, inhibited cell invasion and metastasis, decreased the BCSC population and partially reversed epithelial-mesenchymal transition (EMT) in MDA-MB-231 cells by directly targeting the oncogene, SETDB1. [Stem Cells] Abstract MDM2-Mediated Degradation of SIRT6 Phosphorylated by AKT1 Promotes Tumorigenesis and Trastuzumab Resistance in Breast Cancer Sirtuin 6 (SIRT6) is associated with longevity and is also a tumor suppressor. In various breast cancer cell lines, researchers demonstrate that SIRT6 was phosphorylated at Ser338 by the kinase AKT1, which induced the interaction and ubiquitination of SIRT6 by MDM2, targeting SIRT6 for protease-dependent degradation. [Sci Signal] Abstract Overexpression of Oct4 Suppresses the Metastatic Potential of Breast Cancer Cells via Rnd1 Downregulation Researchers overexpressed and silenced Oct4 expression in two breast cancer cell lines, MDA-MB-231 and 4T1, separately. They showed that ectopic overexpression of Oct4 suppressed cell migration and invasion in vitro and the formation of metastatic lung nodules in vivo. Conversely, Oct4 downregulation increased the metastatic potential of breast cancer cells both in vitro and in vivo. [Biochim Biophys Acta] Abstract Lymphatic Endothelial Cells Support Tumor Growth in Breast Cancer Investigators co-injected endothelial cells with MDA-MB-231 breast cancer cells into animals and showed that lymphatic endothelial cells support tumor growth, human umbilical vein endothelial cells have no significant effect on tumor growth, whereas microvascular endothelial cells suppress it. [Sci Rep] Full Article Critical Roles for Nitric Oxide and ERK in the Completion of Prosurvival Autophagy in 4OHTAM-Treated Estrogen Receptor-Positive Breast Cancer Cells Autophagy is a mechanism of tamoxifen resistance in ER-positive (ER+) breast cancer cells. Investigators showed in ER+ MCF7 cells that 4-hydroxytamoxifen (4OHTAM) induced cellular nitric oxide (NO) that negatively regulates cellular superoxide and cytotoxicity and suggest an essential role for endogenous NO and ERK activation in the completion of pro-survival autophagy. [Cancer Lett] Abstract Selective Androgen Receptor Modulators (SARMs) Negatively Regulate Triple-Negative Breast Cancer Growth and Epithelial: Mesenchymal Stem Cell Signaling Researchers demonstrate that androgen receptor (AR) stimulation inhibits paracrine factors that are important for mesenchymal stem cell interactions and breast cancer invasion and metastasis and that SARMs may provide promise as novel targeted therapies to treat AR-positive triple-negative breast cancer. [PLoS One] Full Article CLINICAL RESEARCH Androgen Receptor Expression in Male Breast Cancer Predicts Inferior Outcome and Poor Response to Tamoxifen Treatment Scientists investigated the role of the androgen receptor (AR) in male breast cancer treatment and prognosis and to analyze the relationship between AR and the effect of tamoxifen treatment therapy in male breast cancer patients. [Eur J Endocrinol] Abstract A Phase I Pharmacokinetics Study of Lapatinib and Tamoxifen in Metastatic Breast Cancer (EORTC 10053 Lapatam Study) Researchers assessed the pharmacokinetic, tolerability, safety and preliminary clinical activity of tamoxifen and lapatinib in patients with metastatic breast cancer. [Breast] Abstract  |