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Recent evidence has highlighted the role of N 6 -methyladenosine (m 6 A) in the regulation of mRNA expression, stability, and translation, supporting a potential role for posttranscriptional regulation mediated by m 6 A in cancer. Here, we explore prostate cancer as an exemplar and demonstrate that low levels of N 6 -adenosine-methyltransferase ( METTL3 ) is associated with advanced metastatic disease. To investigate this relationship, we generated the first prostate m 6 A maps, and further examined how METTL3 regulates expression at the level of transcription, translation, and protein. Significantly, transcripts encoding extracellular matrix proteins are consistently upregulated with METTL3 knockdown. We also examined the relationship between METTL3 and androgen signaling and discovered the upregulation of a hepatocyte nuclear factor-driven gene signature that is associated with therapy resistance in prostate cancer. Significantly, METTL3 knockdown rendered the cells resistant to androgen receptor antagonists via an androgen receptor-independent mechanism driven by the upregulation of nuclear receptor NR5A2/LRH-1 . IMPLICATIONS: These findings implicate changes in m 6 A as a mechanism for therapy resistance in metastatic prostate cancer., (©2021 The Authors; Published by the American Association for Cancer Research.)

Background: Resistance to DNA damaging chemotherapies leads to cancer treatment failure and poor patient prognosis. We investigated how genomic distribution of accessible chromatin sites is altered during acquisition of cisplatin resistance using matched ovarian cell lines from high grade serous ovarian cancer (HGSOC) patients before and after becoming clinically resistant to platinum-based chemotherapy., Results: Resistant lines show altered chromatin accessibility at intergenic regions, but less so at gene promoters. Clusters of cis-regulatory elements at these intergenic regions show chromatin changes that are associated with altered expression of linked genes, with enrichment for genes involved in the Fanconi anemia/BRCA DNA damage response pathway. Further, genome-wide distribution of platinum adducts associates with the chromatin changes observed and distinguish sensitive from resistant lines. In the resistant line, we observe fewer adducts around gene promoters and more adducts at intergenic regions., Conclusions: Chromatin changes at intergenic regulators of gene expression are associated with in vivo derived drug resistance and Pt-adduct distribution in patient-derived HGSOC drug resistance models.

Rationale: Adenylosuccinate lyase (ADSL) is an essential enzyme for de novo purine biosynthesis. Here we sought to investigate the putative role of ADSL in colorectal carcinoma (CRC) carcinogenesis and response to antimetabolites. Methods: ADSL expression levels were assessed by immunohistochemistry or retrieved from The Cancer Genome Atlas (TCGA) dataset. The effects of ADSL silencing or overexpression were evaluated on CRC cell proliferation, cell migration and cell-cycle. In vivo tumor growth was assessed by the chicken chorioallantoic membrane (CAM). Transfected cell lines or patient-derived organoids (PDO) were treated with 5-fluorouracil (5-FU) and 6-mercaptopurine (6-MP) and drug response was correlated with ADSL expression levels. Metabolomic and transcriptomic profiling were performed to identify dysregulated pathways and ADSL downstream effectors. Mitochondrial respiration and glycolytic capacity were measured using Seahorse; mitochondrial membrane potential and the accumulation of ROS were measured by FACS using MitoTracker Red and MitoSOX staining, respectively. Activation of canonical pathways was assessed by immunohistochemistry and immunoblotting. Results: ADSL expression is significantly increased in CRC tumors compared to non-tumor tissue. ADSL-high CRCs show upregulation of genes involved in DNA synthesis, DNA repair and cell cycle. Accordingly, ADSL overexpression accelerated progression through the cell cycle and significantly increased proliferation and migration in CRC cell lines. Additionally, ADSL expression increased tumor growth in vivo and sensitized CRCs to 6-MP in vitro , ex vivo (PDOs) and in vivo (CAM model). ADSL exerts its oncogenic function by affecting mitochondrial function via alteration of the TCA cycle and impairment of mitochondrial respiration. The KEAP1-NRF2 and mTORC1-cMyc axis are independently activated upon ADSL overexpression and may favor the survival and proliferation of ROS-accumulating cells, favoring DNA damage and tumorigenesis. Conclusions: Our results suggest that ADSL is a novel oncogene in CRC, modulating mitochondrial function, metabolism and oxidative stress, thus promoting cell cycle progression, proliferation and migration. Our results also suggest that ADSL is a predictive biomarker of response to 6-mercaptopurine in the pre-clinical setting., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Transcriptional enhancer factor domain family member 4 (TEAD4) is a downstream effector of the conserved Hippo signaling pathway, regulating the expression of genes involved in cell proliferation and differentiation. It is up-regulated in several cancer types and is associated with metastasis and poor prognosis. However, its role in hepatocellular carcinoma (HCC) remains largely unexplored. Using data from The Cancer Genome Atlas, we found that TEAD4 was overexpressed in HCC and was associated with aggressive HCC features and worse outcome. Overexpression of TEAD4 significantly increased proliferation and migration rates in HCC cells in vitro as well as tumor growth in vivo . Additionally, RNA sequencing analysis of TEAD4 -overexpressing HCC cells demonstrated that TEAD4 overexpression was associated with the up-regulation of genes involved in epithelial-to-mesenchymal transition, proliferation, and protein-folding pathways. Among the most up-regulated genes following TEAD4 overexpression were the 70-kDa heat shock protein (HSP70) family members HSPA6 and HSPA1 A. Chromatin immunoprecipitation-quantitative real-time polymerase chain reaction experiments demonstrated that TEAD4 regulates HSPA6 and HSPA1A expression by directly binding to their promoter and enhancer regions. The pharmacologic inhibition of HSP70 expression in TEAD4 -overexpressing cells reduced the effect of TEAD4 on cell proliferation. Finally, by overexpressing TEAD4 in yes-associated protein ( YAP )/transcriptional coactivator with PDZ binding motif ( TAZ )-knockdown HCC cells, we showed that the effect of TEAD4 on cell proliferation and its regulation of HSP70 expression does not require YAP and TAZ, the main effectors of the Hippo signaling pathway. Conclusion: A novel Hippo-independent mechanism for TEAD4 promotes cell proliferation and tumor growth in HCC by directly regulating HSP70 family members., (© 2021 The Authors. Hepatology Communications published by Wiley Periodicals LLC on behalf of the American Association for the Study of Liver Diseases.)

Background: Endogenous retroviruses (ERVs) play a role in a variety of biological processes, including embryogenesis and cancer. DNA methyltransferase inhibitors (DNMTi)-induced ERV expression triggers interferon responses in ovarian cancer cells via the viral sensing machinery. Baseline expression of ERVs also occurs in cancer cells, though this process is poorly understood and previously unexplored in epithelial ovarian cancer (EOC). Here, the prognostic and immunomodulatory consequences of baseline ERV expression was assessed in EOC., Methods: ERV expression was assessed using EOC transcriptional data from The Cancer Genome Atlas (TCGA) and from an independent cohort (Hammersmith Hospital, HH), as well as from untreated or DNMTi-treated EOC cell lines. Least absolute shrinkage and selection operator (LASSO) logistic regression defined an ERV expression score to predict patient prognosis. Immunohistochemistry (IHC) was conducted on the HH cohort. Combination of DNMTi treatment with γδ T cells was tested in vitro , using EOC cell lines and patient-derived tumor cells., Results: ERV expression was found to define clinically relevant subsets of EOC patients. An ERV prognostic score was successfully generated in TCGA and validated in the independent cohort. In EOC patients from this cohort, a high ERV score was associated with better survival (log-rank p=0.0009) and correlated with infiltration of CD8+PD1+T cells (r=0.46, p=0.0001). In the TCGA dataset, a higher ERV score was found in BRCA1/2 mutant tumors, compared to wild type (p=0.015), while a lower ERV score was found in CCNE1 amplified tumors, compared to wild type (p=0.019). In vitro , baseline ERV expression dictates the level of ERV induction in response to DNMTi. Manipulation of an ERV expression threshold by DNMTi resulted in improved EOC cell killing by cytotoxic immune cells., Conclusions: These findings uncover the potential for baseline ERV expression to robustly inform EOC patient prognosis, influence tumor immune infiltration and affect antitumor immunity., Competing Interests: Competing interests: DP received lecture fees from ViiV Healthcare, Bayer Healthcare and travel expenses from BMS and Bayer Healthcare; consulting fees for Mina Therapeutics, EISAI, Roche, Astra Zeneca; received research funding (to institution) from MSD and BMS., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Staphylococcal decolonization decreases the risk of Staphylococcus aureus surgical site infection. This study evaluates patient perceptions and barriers to a universal Staphylococcal decolonization (USD) protocol., Methods: In October 2013, a protocol for the decolonization of Staphylococcal aureus in elective orthopedic, neurosurgical, and cardiac surgeries was implemented in an effort to further decrease post-operative infections rates. We surveyed patients undergoing these procedures between November 2014 and April 2015 using an anonymous, voluntary, Likert-scale survey; survey questions targeted compliance with the protocol as well as barriers to protocol completion., Results: A sample of 546 patients (n=1289, 42%) undergoing elective neurosurgical and orthopedic surgeries completed surveys. Respondents had 85% compliance with USD. Insufficient time prior to the procedure to complete the protocol was the largest barrier to USD completion., Conclusions: This study provides evidence that USD is acceptable to patients, and that the biggest barriers are logistical., (Copyright © 2018. Published by Elsevier Inc.)

Bivalent chromatin domains containing both active H3K4me3 and repressive H3K27me3 histone marks define gene sets poised for expression or silencing in differentiating embryonic stem (ES) cells. In cancer cells, aberrantly poised genes may facilitate changes in transcriptional states after exposure to anticancer drugs. In this study, we used ChIP-seq to characterize genome-wide positioning of H3K4me3- and H3K27me3-associated chromatin in primary high-grade serous ovarian carcinomas and in normal ovarian surface and fallopian tube tissue. Gene sets with proximal bivalent marks defined in this manner were evaluated subsequently as signatures of systematic change in DNA methylation and gene expression, comparing pairs of tissue samples taken from patients at primary presentation and relapse following chemotherapy. We found that gene sets harboring bivalent chromatin domains at their promoters in tumor tissue, but not normal epithelia, overlapped with Polycomb-repressive complex target genes as well as transcriptionally silenced genes in normal ovarian and tubal stem cells. The bivalently marked genes we identified in tumors before chemotherapy displayed increased promoter CpG methylation and reduced gene expression at relapse after chemotherapy of ovarian cancer. Overall, our results support the hypothesis that preexisting histone modifications at genes in a poised chromatin state may lead to epigenetic silencing during acquired drug resistance. Significance: These results suggest epigenetic targets for intervention to prevent the emergence of cancer drug resistance. Cancer Res; 78(6); 1383-91. ©2018 AACR ., (©2018 American Association for Cancer Research.)

In the original publication, Fig. 1 depicting the blot for EP300 in CAL51 cells (Fig. 1c) was unintentionally duplicated with that from MDA-MB-231 cells (Fig. 1d). The new figure given in this erratum depicts the correct EP300 blot in Fig. 1c.

Purpose: We have previously described a novel pathway controlling drug resistance, epithelial-to-mesenchymal transition (EMT) and stemness in breast cancer cells. Upstream in the pathway, three miRs (miR-106b, miR-93 and miR-25) target EP300, a transcriptional activator of E-cadherin. Upregulation of these miRs leads to the downregulation of EP300 and E-cadherin with initiation of an EMT. However, miRs regulate the expression of many genes, and the contribution to EMT by miR targets other than EP300 cannot be ruled out., Methods: We used lentiviruses expressing EP300-targeting shRNA to downregulate its expression in MCF-7 cells as well as an EP300-knocked-out colon carcinoma cell line. An EP300-expression plasmid was used to upregulate its expression in basal-like CAL51 and MDA-MB-231 breast cancer cells. Drug resistance was determined by short-term proliferation and long-term colony formation assays. Stemness was determined by tumour sphere formation in both soft agar and liquid cultures as well as by the expression of CD44/CD24/ALDH markers. Gene expression microarray analysis was performed in MCF-7 cells lacking EP300. EP300 expression was analysed by immunohistochemistry in 17 samples of metaplastic breast cancer., Results: Cells lacking EP300 became more resistant to paclitaxel whereas EP300 overexpression increased their sensitivity to the drug. Expression of cancer stem cell markers, as well as tumour sphere formation, was also increased in EP300-depleted cells, and was diminished in EP300-overexpressing cells. The EP300-regulated gene signature highlighted genes associated with adhesion (CEACAM5), cytoskeletal remodelling (CAPN9), stemness (ABCG2), apoptosis (BCL2) and metastasis (TGFB2). Some genes in this signature were also validated in a previously generated EP300-depleted model of breast cancer using minimally transformed mammary epithelial cells. Importantly, two key genes in apoptosis and stemness, BCL2 and ABCG2, were also upregulated in EP300-knockout colon carcinoma cells and their paclitaxel-resistant derivatives. Immunohistochemical analysis demonstrated that EP300 expression was low in metaplastic breast cancer, a rare, but aggressive form of the disease with poor prognosis that is characterized by morphological and physiological features of EMT., Conclusions: EP300 plays a major role in the reprogramming events, leading to a more malignant phenotype with the acquisition of drug resistance and cell plasticity, a characteristic of metaplastic breast cancer.

Purpose: DNA damage repair can lead to epigenetic changes. DNA mismatch repair proteins bind to platinum DNA adducts and at sites of DNA damage can recruit the DNA methylating enzyme DNMT1, resulting in aberrant methylation. We hypothesised that DNA damage repair during platinum-based chemotherapy may cause aberrant DNA methylation in normal tissues of patients such as blood. Experimental Design: We used Illumina 450k methylation arrays and bisulphite pyrosequencing to investigate methylation at presentation and relapse in blood DNA from patients with ovarian cancer enrolled in the SCOTROC1 trial ( n = 247) and in a cohort of ovarian tumor DNA samples collected at first relapse ( n = 46). We used an ovarian cancer cell line model to investigate the role of the DNA mismatch repair gene MLH1 in platinum-induced methylation changes. Results: Specific CpG methylation changes in blood at relapse are observed following platinum-based chemotherapy and are associated with patient survival, independent of other clinical factors [hazard ratio, 3.7; 95% confidence interval, 1.8-7.6, P = 2.8 × 10 -4 ]. Similar changes occur in ovarian tumors at relapse, also associated with patient survival (hazard ratio, 2.6; 95% confidence interval, 1.0-6.8, P = 0.048). Using an ovarian cancer cell line model, we demonstrate that functional mismatch repair increases the frequency of platinum-induced methylation. Conclusions: DNA methylation in blood at relapse following chemotherapy, and not at presentation, is informative regarding survival of patients with ovarian cancer. Functional DNA mismatch repair increases the frequency of DNA methylation changes induced by platinum. DNA methylation in blood following chemotherapy could provide a noninvasive means of monitoring patients' epigenetic responses to treatment without requiring a tumor biopsy. Clin Cancer Res; 23(9); 2213-22. ©2016 AACR ., (©2016 American Association for Cancer Research.)

A formal convergent synthesis of dictyostatin from (R)-Roche ester is described. Synthetic highlights include a Ni-catalyzed Nozaki-Hiyama-Kishi coupling between an aldehyde and a Z vinyl iodide to assemble the two main fragments, a diastereoselective Myers alkylation, a stereoselective Evans aldolization, two asymmetric Duthaler crotyltitanations, and a stereoselective Pd-catalyzed Marshall allenylindium addition to install the stereogenic centers of dictyostatin. The synthesis of (9R)-epi-dictyostatin and a new ring-contracted dictyostatin isomer were also achieved., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Quorum sensing involving acyl homoserine lactones (AHLs) is a density-dependent form of intercellular communication that occurs in many different members of the group Proteobacteria. However, to date, there have been few investigations of its occurrence in cyanobacteria. Here, using both a bioreporter Agrobacterium tumefaciens NTL4 (PZLR4) and mass spectrometry, we provide evidence of N-octanoyl homoserine lactone (C8-AHL) production in axenic cultures of the cyanobacterium Gloeothece PCC6909 and its sheathless mutant PCC6909/1. Accumulation of C8-AHL in the culture medium of laboratory cultures of Gloeothece followed a pattern characteristic of the phenomenon of autoinduction, a common feature of functional AHL-based quorum-sensing systems. Analysis by two-dimensional gel electrophoresis showed that, in response to treatment with C8-AHL, early growth-stage cells of PCC6909/1 showed changes in expression of 43 proteins compared with untreated cells. Among the 15 proteins that showed more than a twofold change in expression were RuBisCo, glutamate synthase, chorismate synthase, a member of the LysR family of transcriptional regulators (all upregulated), and enolase and aldolase, both of which were downregulated. The significance of such changes in response to C8-AHL is discussed in relation to carbohydrate and amino-acid metabolism and involvement of Gloeothece in biofilms.

A study was made of the biosynthesis by Anabaena flos-aquae of the tropane-related alkaloid anatoxin-a. Evidence is presented that the toxin arises from ornithine via putrescine (1,4-diaminobutane) and that ornithine decarboxylase (EC 4.1.1.17) is involved. An ornithine decarboxylase preparation, with optimal activity at pH 8, was obtained from Anabaena flos-aquae and partially purified by gel-filtration chromatography on DEAE-cellulose. One major and one minor peak of enzymic activity were obtained with Km values of 1.25 and 2.5 mM, respectively. Plasmid DNA (10 Kb; Mr 6.5 x 10(6] was detected in the toxic strain of Anabaena flos-aquae but not in a non-toxic strain. DNA from the toxin-producing strain of Anabaena flos-aquae transforms the non-toxic into a toxic strain.

Sixty-three patients with arteriopathies confirmed by arteriography when they were under 40 years of age were followed up for between 1 and 7 years. The arteriopathy was due to atheroma in 23 cases, to miscellaneous in 22 cases, and to Buerger's disease less frequently (18 cases), suggesting that atheroma should be suspected as being at the origin of an arteriopathy initially in young subjects. Confirmation of the basic nature of the affection is based on several criteria, the most reliable being results of angiography and the detection of associated lesions in other localizations. Histology is a decisive element, but biopsy may involve risks and results are sometimes difficult to interpret. Treatment depends more on clinical symptomatology and the localizations of arterial occlusion than on the nature of the arteriopathy. Sympathectomy is effective in distal lesions, whereas revascularization, adapted to the often small size of the vessels involved and potential impairment in distal vessel circulation, is necessary for proximal lesions. Overall prognosis is more satisfactory in Buerger's disease than in arteriopathy of atheromatous origin, rapid progression occurring in half of the latter cases.