LABORATORY RESEARCH Reactivation of Multipotency by Oncogenic PIK3CA Induces Breast Tumor Heterogeneity Concomitant deletion of p53 and expression of Pik3caH1047R accelerated tumor development and induced more aggressive mammary tumors. Expression of Pik3caH1047R in unipotent basal cells gave rise to luminal-like cells, while its expression in unipotent luminal cells gave rise to basal-like cells before progressing into invasive tumors. [Nature] Abstract | Press Release The Inositol Polyphosphate 5-Phosphatase PIPP Regulates AKT1-Dependent Breast Cancer Growth and Metastasis Investigators showed that depletion of the inositol polyphosphate 5-phosphatase PIPP increases breast cancer cell transformation, but reduces cell migration and invasion. Pipp ablation accelerates oncogene-driven breast cancer tumor growth in vivo, but paradoxically reduces metastasis by regulating AKT1-dependent tumor cell migration. [Cancer Cell] Abstract | Graphical Abstract | Press Release Real-Time Imaging Reveals Local, Transient Vascular Permeability, and Tumor Cell Intravasation Stimulated by TIE2hi Macrophage–Derived VEGFA VEGFA signaling from TIE2hi tumor microenvironment of metastasis macrophages causes local loss of vascular junctions, transient vascular permeability, and tumor cell intravasation, demonstrating a role for the TMEM within the primary mammary tumor. [Cancer Discov] Abstract | Press Release Genome-Wide Lentiviral ShRNA Screen Identifies Serine/Arginine-Rich Splicing Factor 2 as a Determinant of Oncolytic Virus Activity in Breast Cancer Cells The authors used a pooled genome-wide short hairpin RNA library and found that depletion of the splicing factor arginine-rich splicing factor 2 leads to enhanced cytotoxicity of breast cancer cells by KM100. [Oncogene] Abstract miR-378a-3p Modulates Tamoxifen Sensitivity in Breast Cancer MCF-7 Cells through Targeting GOLT1A Investigators found that miR-378a-3p expression was downregulated in tamoxifen-resistant (TamR) and long-term estrogen-deprived cells as well as in clinical breast cancer tissues. GOLT1A was overexpressed in breast cancer specimens and GOLT1A-specific siRNAs inhibited the growth of TamR cells. [Sci Rep] Full Article Rhus coriaria Induces Senescence and Autophagic Cell Death in Breast Cancer Cells through a Mechanism Involving p38 and ERK1/2 Activation Scientists investigated the anticancer effect of Rhus coriaria on three breast cancer cell lines. They demonstrated that Rhus coriaria ethanolic extract inhibits the proliferation of these cell lines in a time- and concentration-dependent manner. [Sci Rep] Full Article PEAK1 Acts as a Molecular Switch to Regulate Context-Dependent TGFβ Responses in Breast Cancer Researchers observed that PEAK1 expression was highest in mesenchymal breast cancer cells, correlated with migration potential and increased in response to transforming growth factor β (TGFβ)-induced epithelial-mesenchymal transition. [PLoS One] Full Article MCF-7 Human Breast Cancer Cells Form Differentiated Microtissues in Scaffold-Free Hydrogels When compared to MCF-7 cells cultured in two-dimensional monolayer culture, MCF-7 microtissues exhibit increased mRNA expression of luminal epithelial markers keratin 8 and keratin 19 and decreased expression of basal marker keratin 14 and the mesenchymal marker vimentin [PLoS One] Full Article Activin-A Signaling Promotes Epithelial–Mesenchymal Transition, Invasion, and Metastatic Growth of Breast Cancer Investigators evaluated the status and role of Activin-A signaling pathway in breast tumors. Activin-A promoted anchorage-independent growth, epithelial–mesenchymal transition, invasion, angiogenesis, and stemness of breast cancer cells. [npj Breast Cancer] Full Article CLINICAL RESEARCH HAGE in Triple Negative Breast Cancer (TNBC) Is a Novel Prognostic, Predictive and Actionable Biomarker: A Transcriptomic and Protein Expression Analysis HAGE protein expression was investigated in an early primary TNBC cohort who received adjuvant chemotherapy (ACT) and in a locally advanced primary TNBC cohort who received anthracycline-combination Neo-ACT. [Clin Cancer Res] Abstract | Press Release Phase I Trial of Afatinib plus Vinorelbine in Japanese Patients with Advanced Solid Tumors, Including Breast Cancer Investigators assessed afatinib, an irreversible ErbB family blocker, plus vinorelbine in Japanese patients with advanced solid tumors not amenable to standard treatment. [Cancer Chemother Pharmacol] Abstract |