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Heterochromatin that depends on histone H3 lysine 9 methylation (H3K9me) renders embedded genes transcriptionally silent.sup.1-3. In the fission yeast Schizosaccharomyces pombe, H3K9me heterochromatin can be transmitted through cell division provided the counteracting demethylase Epe1 is absent.sup.4,5. Heterochromatin heritability might allow wild-type cells under certain conditions to acquire epimutations, which could influence phenotype through unstable gene silencing rather than DNA change.sup.6,7. Here we show that heterochromatin-dependent epimutants resistant to caffeine arise in fission yeast grown with threshold levels of caffeine. Isolates with unstable resistance have distinct heterochromatin islands with reduced expression of embedded genes, including some whose mutation confers caffeine resistance. Forced heterochromatin formation at implicated loci confirms that resistance results from heterochromatin-mediated silencing. Our analyses reveal that epigenetic processes promote phenotypic plasticity, letting wild-type cells adapt to unfavourable environments without genetic alteration. In some isolates, subsequent or coincident gene-amplification events augment resistance. Caffeine affects two anti-silencing factors: Epe1 is downregulated, reducing its chromatin association, and a shortened isoform of Mst2 histone acetyltransferase is expressed. Thus, heterochromatin-dependent epimutation provides a bet-hedging strategy allowing cells to adapt transiently to insults while remaining genetically wild type. Isolates with unstable caffeine resistance show cross-resistance to antifungal agents, suggesting that related heterochromatin-dependent processes may contribute to resistance of plant and human fungal pathogens to such agents. Fission yeast grown in sublethal levels of caffeine develop heterochromatin-dependent epimutations conferring unstable heritable gene silencing that conveys resistance to caffeine, while remaining genetically wild type., Author(s): Sito Torres-Garcia [sup.1] , Imtiyaz Yaseen [sup.1] , Manu Shukla [sup.1] , Pauline N. C. B. Audergon [sup.1] [sup.2] , Sharon A. White [sup.1] , Alison L. Pidoux [sup.1] [...]

BackgroundAromatase inhibitors such as anastrozole and letrozole are highly effective suppressants of estrogen synthesis in postmenopausal women and are the most effective endocrine treatments for hormone receptor positive breast cancer in such women. Little is known of the molecular effects of these agents on human breast carcinomas in vivo.MethodsWe randomly assigned primary estrogen receptor positive breast cancer patients to treatment with anastrozole or letrozole for 2 weeks before surgery. Expression profiling using cDNA arrays was conducted on pretreatment and post-treatment biopsies. Sample pairs from 34 patients provided sufficient RNA for analysis.ResultsProfound changes in gene expression were seen with both aromatase inhibitors, including many classical estrogen-dependent genes such as TFF1, CCND1, PDZK1 and AGR2, but also many other genes that are likely to represent secondary responses; decrease in the expression of proliferation-related genes were particularly prominent. Many upregulated genes are involved in extracellular matrix remodelling, including collagens and members of the small leucine-rich proteoglycan family (LUM, DCN, and ASPN). No significant differences were seen between letrozole and anastrozole in terms of molecular effects. The gene changes were integrated into a Global Index of Dependence on Estrogen (GIDE), which enumerates the genes changing by at least twofold with therapy. The GIDE varied markedly between tumours and related significantly to pretreatment levels of HER2 and changes in immunohistochemically detected Ki67.ConclusionOur findings identify the transcriptional signatures associated with aromatase inhibitor treatment of primary breast tumours. Larger datasets using this approach should enable identification of estrogen-dependent molecular changes, which are the determinants of benefit or resistance to endocrine therapy.

Simple Summary: Triple-negative breast cancer is characterized by a lack of targetable treatment receptors and current standard of care options, such as radiation therapy and chemotherapy, are associated with acute patient toxicity. Noninvasive imaging of PD-L1, with [89Zr]-Atezolizumab-PET imaging, has the potential to identify tumors with increased susceptibility to immunotherapy. In this work, we have optimized the labeling conditions of [89Zr]-Atezolizumab and used noninvasive [89Zr]-Atezolizumab PET imaging to characterize the longitudinal changes in PD-L1 expression in TNBC treated with standard of care treatment options. The goal of this study is to understand how [89Zr]-Atezolizumab PET imaging can characterize changes in intratumoral molecular biology and how this can inform eventual response and combination therapy. Triple-negative breast cancers (TNBCs) currently have limited treatment options; however, PD-L1 is an indicator of susceptibility to immunotherapy. Currently, assessment of PD-L1 is limited to biopsy samples. These limitations may be overcome with molecular imaging. In this work, we describe chemistry development and optimization, in vitro, in vivo, and dosimetry of [89Zr]-Atezolizumab for PD-L1 imaging. Atezolizumab was conjugated to DFO and radiolabeled with 89Zr. Tumor uptake and heterogeneity in TNBC xenograft and patient-derived xenograft (PDX) mouse models were quantified following [89Zr]-Atezolizumab-PET imaging. PD-L1 expression in TNBC PDX models undergoing therapy and immunohistochemistry (IHC) was used to validate imaging. SUV from PET imaging was quantified and used to identify heterogeneity. PET/CT imaging using [89Zr]-Atezolizumab identified a significant increase in tumor:muscle SUVmean 1 and 4 days after niraparib therapy and revealed an increased trend in PD-L1 expression following other cytotoxic therapies. A preliminary dosimetry study indicated the organs that will receive a higher dose are the spleen, adrenals, kidneys, and liver. [89Zr]-Atezolizumab PET/CT imaging reveals potential for the noninvasive detection of PD-L1-positive TNBC tumors and allows for quantitative and longitudinal assessment. This has potential significance for understanding tumor heterogeneity and monitoring early expression changes in PD-L1 induced by therapy. [ABSTRACT FROM AUTHOR]

With the changing demographics of the American workforce, the National Science Foundation, along with the U.S. Department of Commerce, has highlighted the shortage of minorities in information technology (IT) careers (http://www.ta.doc.gov/Reports/itsw/itsw.pdf). Using data from a 6-year period and the psychology Involvement-Regimen-Self Management-Social (IRSS) network theory as defined by Boice (1992), we discuss lessons learned from mentoring a group of Information Systems doctoral students who are members of a pipeline that can potentially increase the number of underrepresented faculty in business schools and who made conscious decisions to renounce the IT corporate domain. While our lessons speak to the need for more diversity awareness, we conclude that effective mentoring for underrepresented groups can and should include faculty of color (though limited in numbers) as well as majority faculty who are receptive to the needs and cultural differences of these student groups. Lastly, we draw on the work of "Ethnic America" to provide additional insight into our findings that are not offered by IRSS network theory.

Assistant principals are often overlooked as a resource for creating, advancing, and sustaining a compelling vision for mathematics. The Math Collaborative Project developed in New York City examined the process of developing and implementing programs designed to help assistant principals network and strengthen their instructional leadership capacity in mathematics within an urban setting. In this project, assistant principals participated in mathematics instruction, reflected on their roles, shared concerns about their work, and supervised lessons. The participants took what they learned back to their schools to improve mathematics instruction for their students. With their enthusiasm for change in the mathematics culture, assistant principals can help teachers come to believe that they are valued, supported, and able to make mathematics less isolating for students.

Background: Survivorship care plans (SCPs) communicate cancer‐related information from oncology providers to patients and primary care providers. SCPs may limit overuse testing by specifying necessary follow‐up care. From a randomized, controlled trial of SCP delivery, we examined whether cancer‐related tests not specified in SCPs, but conducted after SCP receipt, were appropriate or consistent with overuse. Methods: Survivors of breast, colorectal, or prostate cancer treated at urban‐academic or rural‐community health systems were randomized to one of three SCP delivery arms. Tests during 18 months after SCP receipt were classified as consistent with overuse if they were (1) not included in SCPs and (2) on a guideline‐based predetermined list of "not recommended surveillance." After chart abstraction, physicians performed review and adjudication of potential overuse. Descriptive analyses were conducted of tests consistent with overuse. Negative binomial regression models determined if testing consistent with overuse differed across study arms. Results: Among 316 patients (137 breast, 67 colorectal, 112 prostate), 140 individual tests were identified as potential overuse. Upon review, 98 were deemed to be consistent with overuse: 78 tumor markers and 20 imaging tests. The majority of overuse testing was breast cancer‐related (95%). Across sites, 27 patients (9%) received ≥1 test consistent with overuse; most were breast cancer patients (22/27). Exploratory analyses of overuse test frequency by study arm showed no significant difference. Conclusions: This analysis identified practice patterns consistent with overuse of surveillance testing and can inform efforts to improve guideline‐concordant care. Future interventions may include individual practice patterns and provider education. [ABSTRACT FROM AUTHOR]