Dynamic classification using case-specific training cohorts outperforms static gene expression signatures in breast cancer

The molecular diversity of breast cancer makes it impossible to identify prognostic markers that are applicable to all breast cancers. To overcome limitations of previous multigene prognostic classifiers, we propose a new dynamic predictor: instead of using a single universal training cohort and an identical list of informative genes to predict the prognosis of new cases, a case-specific predictor is developed for each test case. Gene expression data from 3,534 breast cancers with clinical annotation including relapse-free survival is analyzed. For each test case, we select a case-specific training subset including only molecularly similar cases and a case-specific predictor is generated. This method yields different training sets and different predictors for each new patient. The model performance was assessed in leave-one-out validation and also in 325 independent cases. Prognostic discrimination was high for all cases (n = 3,534, HR = 3.68, p = 1.67 E-56). The dynamic predictor showed higher overall accuracy (0.68) than genomic surrogates for Oncotype DX (0.64), Genomic Grade Index (0.61) or MammaPrint (0.47). The dynamic predictor was also effective in triple-negative cancers (n = 427, HR = 3.08, p = 0.0093) where the above classifiers all failed. Validation in independent patients yielded similar classification power (HR = 3.57). The dynamic classifier is available online at http://www.recurrenceonline.com/?q=Re_training. In summary, we developed a new method to make personalized prognostic prediction using case-specific training cohorts. The dynamic predictors outperform static models developed from single historical training cohorts and they also predict well in triple-negative cancers

Benzyl Isothiocyanate potentiates p53 signaling and antitumor effects against breast cancer through activation of p53-LKB1 and p73-LKB1 axes.

Functional reactivation of p53 pathway, although arduous, can potentially provide a broad-based strategy for cancer therapy owing to frequent p53 inactivation in human cancer. Using a phosphoprotein-screening array, we found that Benzyl Isothiocynate, (BITC) increases p53 phosphorylation in breast cancer cells and reveal an important role of ERK and PRAS40/MDM2 in BITC-mediated p53 activation. We show that BITC rescues and activates p53-signaling network and inhibits growth of p53-mutant cells. Mechanistically, BITC induces p73 expression in p53-mutant cells, disrupts the interaction of p73 and mutant-p53, thereby releasing p73 from sequestration and allowing it to be transcriptionally active. Furthermore, BITC-induced p53 and p73 axes converge on tumor-suppressor LKB1 which is transcriptionally upregulated by p53 and p73 in p53-wild-type and p53-mutant cells respectively; and in a feed-forward mechanism, LKB1 tethers with p53 and p73 to get recruited to p53-responsive promoters. Analyses of BITC-treated xenografts using LKB1-null cells corroborate in vitro mechanistic findings and establish LKB1 as the key node whereby BITC potentiates as well as rescues p53-pathway in p53-wild-type as well as p53-mutant cells. These data provide first in vitro and in vivo evidence of the integral role of previously unrecognized crosstalk between BITC, p53/LKB1 and p73/LKB1 axes in breast tumor growth-inhibition

Az orvosnői hivatás magatartástudományi vizsgálata = Behavioural sciences perspective of the medical profession by female physicians

Jelen tanulmányunk folytatni kívánja azt a 16 évvel ezelőtt készült munkát, amely a magyar­országi orvosok/orvosnők egészségi állapotát, életminőségét tárta fel. A kiugróan rossz mortalitási és morbiditási mutatók hátterében akkor az egyenlőtlen terhelés, a mozgásszegény életmód és a kedvezőtlen életkörülmények szerepeltek magyarázó változóként. 2001 tavaszán 72 orvosnővel készítettünk életút-interjút, és vettünk fel az egészségi állapotukra vonatkozó kérdőívet. Vizsgálatunk legfőbb célja az volt, hogy feltérképezzük az orvosnők hivatásbeli és családi terheinek alakulását, megvizsgáljuk  az  egészségügyi problémákat, a  szerepkonfliktusokat, illetve ezek megoldási kísérleteit.  Kutatásunk az életút számos fontos elemét igyekezett megvizsgálni: a pályaválasztás, szakválasztás kérdésétől a munkahelyeken át a család és az anyaság kérdéséig.  Munkánk ugyanakkor előtanulmánynak tekinthető, amely későbbi egészségi állapottal és szerepkonfliktussal kapcsolatos országos vizsgálat alapjául szolgálhat

miRpower: a web-tool to validate survival-associated miRNAs utilizing expression data from 2178 breast cancer patients

PURPOSE: The proper validation of prognostic biomarkers is an important clinical issue in breast cancer research. MicroRNAs (miRNAs) have emerged as a new class of promising breast cancer biomarkers. In the present work, we developed an integrated online bioinformatic tool to validate the prognostic relevance of miRNAs in breast cancer. METHODS: A database was set up by searching the GEO, EGA, TCGA, and PubMed repositories to identify datasets with published miRNA expression and clinical data. Kaplan-Meier survival analysis was performed to validate the prognostic value of a set of 41 previously published survival-associated miRNAs. RESULTS: All together 2178 samples from four independent datasets were integrated into the system including the expression of 1052 distinct human miRNAs. In addition, the web-tool allows for the selection of patients, which can be filtered by receptors status, lymph node involvement, histological grade, and treatments. The complete analysis tool can be accessed online at: www.kmplot.com/mirpower . We used this tool to analyze a large number of deregulated miRNAs associated with breast cancer features and outcome, and confirmed the prognostic value of 26 miRNAs. A significant correlation in three out of four datasets was validated only for miR-29c and miR-101. CONCLUSIONS: In summary, we established an integrated platform capable to mine all available miRNA data to perform a survival analysis for the identification and validation of prognostic miRNA markers in breast cancer

miR-34a Silences c-SRC to Attenuate Tumor Growth in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an aggressive subtype with no clinically proven biologically targeted treatment options. The molecular heterogeneity of TNBC and lack of high frequency driver mutations other than TP53 have hindered the development of new and effective therapies that significantly improve patient outcomes. miRNAs, global regulators of survival and proliferation pathways important in tumor development and maintenance, are becoming promising therapeutic agents. We performed miRNA-profiling studies in different TNBC subtypes to identify miRNAs that significantly contribute to disease progression. We found that miR-34a was lost in TNBC, specifically within mesenchymal and mesenchymal stem cell-like subtypes, whereas expression of miR-34a targets was significantly enriched. Furthermore, restoration of miR-34a in cell lines representing these subtypes inhibited proliferation and invasion, activated senescence, and promoted sensitivity to dasatinib by targeting the proto-oncogene c-SRC. Notably, SRC depletion in TNBC cell lines phenocopied the effects of miR-34a reintroduction, whereas SRC overexpression rescued the antitumorigenic properties mediated by miR-34a. miR-34a levels also increased when cells were treated with c-SRC inhibitors, suggesting a negative feedback exists between miR-34a and c-SRC. Moreover, miR-34a administration significantly delayed tumor growth of subcutaneously and orthotopically implanted tumors in nude mice, and was accompanied by c-SRC downregulation. Finally, we found that miR-34a and SRC levels were inversely correlated in human tumor specimens. Together, our results demonstrate that miR-34a exerts potent antitumorigenic effects in vitro and in vivo and suggests that miR-34a replacement therapy, which is currently being tested in human clinical trials, represents a promising therapeutic strategy for TNBC. Cancer Res; 76(4); 1-13. (c)2015 AACR

PO-357 SREBP1 drives cell-autonomous cytoskeletal changes by KRT80 remodelling during ERα breast cancer progression

Introduction Approximately 30% of oestrogen receptor α positive (ERα) breast cancer patients progress to invasive metastatic disease despite adjuvant treatment with targeted endocrine therapies. The relationship between acquisition of drug resistance and invasive potential is poorly understood. Currently, invasive behaviour is thought to be driven mainly by epithelial to mesenchymal transition. Material and methods MCF7 cell line and derived resistant clones were used for this study. MCF7 Tamoxifen Resistant (MCF7TR) and LTED (Long Term Oestrogen Deprivation) were derived from MCF7 upon one-year Tamoxifen or oestrogen deprivation, respectively. LTED combination treatments were also used (LTEDT and LTEDF). Additionally, we used T47D and T47D-LTED. Stable cell lines were generated for both KRT80 over-expression and knockdown. 3D organoids invasion assay, immunofluorescence, confocal microscopy, RNA-seq, ChIP-seq, RT-qPCR and Western blot were performed. Seventy-five human breast specimens and ten metastatic lymph nodes were selected with the approval of Imperial College Healthcare NHS Trust Tissue Bank. Twenty women with suspected breast cancer were prospectively recruited and radiological exam using shear wave ultrasound was used to determine tissue stiffness in the normal and peri-tumoral stroma, and suspected lesion. Results and discussions In this study, we show that cells that acquire resistance to aromatase inhibitors (AI) undergo active cytoskeleton re-organisation via Keratin 80 (KRT80) and F-Actin remodelling. These features directly drive the invasive phenotype. Mechanistically, we show that this process is driven by epigenetic reprogramming at the type II keratin locus (chromosome 12) leading to Keratin 80 (KRT80) up-regulation. Reprogramming is dependent on de novo SREBP1 binding to a single enhancer that is activated upon chronic AI treatment. AI-treated patients show KRT80 cytoskeletal re-organisation and an increased number of KRT80 positive cells at relapse. We find that KRT80 activation and redeployment leads to increased F-actin deposition and focal adhesion. Additionally, we show that KRT80 manipulation directly contributes to changes in cellular stiffness and invasive potential. In agreement, shear-wave elasticity imaging of prospective patients show that KRT80 levels correlate with stiffer tumours in vivo. Conclusion Collectively, our data uncover an unexpected and potentially targetable link between epigenetic reprogramming and cytoskeletal changes promoting cell invasion

Identifying Cancers Impacted by CDK8/19

CDK8 and CDK19 Mediator kinases are transcriptional co-regulators implicated in several types of cancer. Small-molecule CDK8/19 inhibitors have recently entered or are entering clinical trials, starting with breast cancer and acute myeloid leukemia (AML). To identify other cancers where these novel drugs may provide benefit, we queried genomic and transcriptomic databases for potential impact of CDK8, CDK19, or their binding partner CCNC. sgRNA analysis of a panel of tumor cell lines showed that most tumor types represented in the panel, except for some central nervous system tumors, were not dependent on these genes. In contrast, analysis of clinical samples for alterations in these genes revealed a high frequency of gene amplification in two highly aggressive subtypes of prostate cancer and in some cancers of the GI tract, breast, bladder, and sarcomas. Analysis of survival correlations identified a group of cancers where CDK8 expression correlated with shorter survival (notably breast, prostate, cervical cancers, and esophageal adenocarcinoma). In some cancers (AML, melanoma, ovarian, and others), such correlations were limited to samples with a below-median tumor mutation burden. These results suggest that Mediator kinases are especially important in cancers that are driven primarily by transcriptional rather than mutational changes and warrant an investigation of their role in additional cancer types

Dynamin impacts homology-directed repair and breast cancer response to chemotherapy

After the initial responsiveness of triple-negative breast cancers (TNBCs) to chemotherapy, they often recur as chemotherapy-resistant tumors, and this has been associated with upregulated homology-directed repair (HDR). Thus, inhibitors of HDR could be a useful adjunct to chemotherapy treatment of these cancers. We performed a high-throughput chemical screen for inhibitors of HDR from which we obtained a number of hits that disrupted microtubule dynamics. We postulated that high levels of the target molecules of our screen in tumors would correlate with poor chemotherapy response. We found that inhibition or knockdown of dynamin 2 (DNM2), known for its role in endocytic cell trafficking and microtubule dynamics, impaired HDR and improved response to chemotherapy of cells and of tumors in mice. In a retrospective analysis, levels of DNM2 at the time of treatment strongly predicted chemotherapy outcome for estrogen receptor-negative and especially for TNBC patients. We propose that DNM2-associated DNA repair enzyme trafficking is important for HDR efficiency and is a powerful predictor of sensitivity to breast cancer chemotherapy and an important target for therapy