The genomic region of the 3' untranslated region (3'UTR) of PHO84, rather than the antisense RNA, promotes gene repression.

PHO84 is a budding yeast gene reported to be negatively regulated by its cognate antisense transcripts both in cis and in trans. In this study, we performed Transient-transcriptome sequencing (TT-seq) to investigate the correlation of sense/antisense pairs in a dbp2Δ strain and found over 700 sense/antisense pairs, including PHO84, to be positively correlated, contrasting the prevailing model. To define what mechanism regulates the PHO84 gene and how this regulation could have been originally attributed to repression by the antisense transcript, we conducted a series of molecular biology and genetics experiments. We now report that the 3' untranslated region (3'UTR) of PHO84 plays a repressive role in sense expression, an activity not linked to the antisense transcripts. Moreover, we provide results of a genetic screen for 3'UTR-dependent repression of PHO84 and show that the vast majority of identified factors are linked to negative regulation. Finally, we show that the PHO84 promoter and terminator form gene loops which correlate with transcriptional repression, and that the RNA-binding protein, Tho1, increases this looping and the 3'UTR-dependent repression. Our results negate the current model for antisense non-coding transcripts of PHO84 and suggest that many of these transcripts are byproducts of open chromatin.

The RNA helicase DDX5 supports mitochondrial function in small cell lung cancer.

DEAD-box helicase 5 (DDX5) is a founding member of the DEAD-box RNA helicase family, a group of enzymes that regulate ribonucleoprotein formation and function in every aspect of RNA metabolism, ranging from synthesis to decay. Our laboratory previously found that DDX5 is involved in energy homeostasis, a process that is altered in many cancers. Small cell lung cancer (SCLC) is an understudied cancer type for which effective treatments are currently unavailable. Using an array of methods, including short hairpin RNA-mediated gene silencing, RNA and ChIP sequencing analyses, and metabolite profiling, we show here that DDX5 is overexpressed in SCLC cell lines and that its down-regulation results in various metabolic and cellular alterations. Depletion of DDX5 resulted in reduced growth and mitochondrial dysfunction in the chemoresistant SCLC cell line H69AR. The latter was evidenced by down-regulation of genes involved in oxidative phosphorylation and by impaired oxygen consumption. Interestingly, DDX5 depletion specifically reduced intracellular succinate, a TCA cycle intermediate that serves as a direct electron donor to mitochondrial complex II. We propose that the oncogenic role of DDX5, at least in part, manifests as up-regulation of respiration supporting the energy demands of cancer cells.

Enrichment of Root Endophytic Bacteria from Populus deltoides and Single-Cell-Genomics Analysis.

UNLABELLED: Bacterial endophytes that colonize Populus trees contribute to nutrient acquisition, prime immunity responses, and directly or indirectly increase both above- and below-ground biomasses. Endophytes are embedded within plant material, so physical separation and isolation are difficult tasks. Application of culture-independent methods, such as metagenome or bacterial transcriptome sequencing, has been limited due to the predominance of DNA from the plant biomass. Here, we describe a modified differential and density gradient centrifugation-based protocol for the separation of endophytic bacteria from Populus roots. This protocol achieved substantial reduction in contaminating plant DNA, allowed enrichment of endophytic bacteria away from the plant material, and enabled single-cell genomics analysis. Four single-cell genomes were selected for whole-genome amplification based on their rarity in the microbiome (potentially uncultured taxa) as well as their inferred abilities to form associations with plants. Bioinformatics analyses, including assembly, contamination removal, and completeness estimation, were performed to obtain single-amplified genomes (SAGs) of organisms from the phyla Armatimonadetes, Verrucomicrobia, and Planctomycetes, which were unrepresented in our previous cultivation efforts. Comparative genomic analysis revealed unique characteristics of each SAG that could facilitate future cultivation efforts for these bacteria. IMPORTANCE: Plant roots harbor a diverse collection of microbes that live within host tissues. To gain a comprehensive understanding of microbial adaptations to this endophytic lifestyle from strains that cannot be cultivated, it is necessary to separate bacterial cells from the predominance of plant tissue. This study provides a valuable approach for the separation and isolation of endophytic bacteria from plant root tissue. Isolated live bacteria provide material for microbiome sequencing, single-cell genomics, and analyses of genomes of uncultured bacteria to provide genomics information that will facilitate future cultivation attempts.

Evaluation and validation of de novo and hybrid assembly techniques to derive high-quality genome sequences.

MOTIVATION: To assess the potential of different types of sequence data combined with de novo and hybrid assembly approaches to improve existing draft genome sequences. RESULTS: Illumina, 454 and PacBio sequencing technologies were used to generate de novo and hybrid genome assemblies for four different bacteria, which were assessed for quality using summary statistics (e.g. number of contigs, N50) and in silico evaluation tools. Differences in predictions of multiple copies of rDNA operons for each respective bacterium were evaluated by PCR and Sanger sequencing, and then the validated results were applied as an additional criterion to rank assemblies. In general, assemblies using longer PacBio reads were better able to resolve repetitive regions. In this study, the combination of Illumina and PacBio sequence data assembled through the ALLPATHS-LG algorithm gave the best summary statistics and most accurate rDNA operon number predictions. This study will aid others looking to improve existing draft genome assemblies. AVAILABILITY AND IMPLEMENTATION: All assembly tools except CLC Genomics Workbench are freely available under GNU General Public License. CONTACT: brownsd@ornl.gov SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Lansoprazole interferes with fungal respiration and acts synergistically with amphotericin B against multidrug-resistant Candida auris.

Candida auris has emerged as a problematic fungal pathogen associated with high morbidity and mortality. Amphotericin B (AmB) is the most effective antifungal used to treat invasive fungal candidiasis, with resistance rarely observed among clinical isolates. However, C. auris possesses extraordinary resistant profiles against all available antifungal drugs, including AmB. In our pursuit of potential solutions, we screened a panel of 727 FDA-approved drugs. We identified the proton pump inhibitor lansoprazole (LNP) as a potent enhancer of AmB's activity against C. auris. LNP also potentiates the antifungal activity of AmB against other medically important species of Candida and Cryptococcus. Our investigations into the mechanism of action unveiled that LNP metabolite(s) interact with a crucial target in the mitochondrial respiratory chain (complex III, known as cytochrome bc1). This interaction increases oxidative stress within fungal cells. Our results demonstrated the critical role of an active respiratory function in the antifungal activity of LNP. Most importantly, LNP restored the efficacy of AmB in an immunocompromised mouse model, resulting in a 1.7-log (∼98%) CFU reduction in the burden of C. auris in the kidneys. Our findings strongly advocate for a comprehensive evaluation of LNP as a cytochrome bc1 inhibitor for combating drug-resistant C. auris infections.

Tumor-specific activation of folate receptor beta enables reprogramming of immune cells in the tumor microenvironment.

Folate receptors can perform folate transport, cell adhesion, and/or transcription factor functions. The beta isoform of the folate receptor (FRß) has attracted considerable attention as a biomarker for immunosuppressive macrophages and myeloid-derived suppressor cells, however, its role in immunosuppression remains uncharacterized. We demonstrate here that FRß cannot bind folate on healthy tissue macrophages, but does bind folate after macrophage incubation in anti-inflammatory cytokines or cancer cell-conditioned media. We further show that FRß becomes functionally active following macrophage infiltration into solid tumors, and we exploit this tumor-induced activation to target a toll-like receptor 7 agonist specifically to immunosuppressive myeloid cells in solid tumors without altering myeloid cells in healthy tissues. We then use single-cell RNA-seq to characterize the changes in gene expression induced by the targeted repolarization of tumor-associated macrophages and finally show that their repolarization not only changes their own phenotype, but also induces a proinflammatory shift in all other immune cells of the same tumor mass, leading to potent suppression of tumor growth. Because this selective reprogramming of tumor myeloid cells is accompanied by no systemic toxicity, we propose that it should constitute a safe method to reprogram the tumor microenvironment.

miR-497 target gene regulatory network in angiosarcoma.

Angiosarcoma is a vascular sarcoma that is highly aggressive and metastatic. Due to its rarity, treatment options for patients are limited, therefore more research is needed to identify possible therapeutic vulnerabilities. We previously found that conditional deletion of Dicer1 drives angiosarcoma development in mice. Given the role of DICER1 in canonical microRNA (miRNA) biogenesis, this suggests that miRNA loss is important in angiosarcoma development. After testing miRNAs previously suggested to have a tumor-suppressive role in angiosarcoma, microRNA-497-5p (miR-497) suppressed cell viability most significantly. We also found that miR-497 overexpression led to significantly reduced cell migration and tumor formation. To understand the mechanism of miR-497 in tumor suppression, we identified clinically relevant target genes using a combination of RNA-sequencing data in an angiosarcoma cell line, expression data from angiosarcoma patients, and target prediction algorithms. We validated miR-497 direct regulation of CCND2, CDK6, and VAT1. One of these genes, VAT1, is an understudied protein that has been suggested to promote cell migration and metastasis in other cancers. Indeed, we find that pharmacologic inhibition of VAT1 with the natural product Neocarzilin A reduces angiosarcoma migration. Implications: This work supports the potent tumor-suppressive abilities of miR-497 in angiosarcoma, providing evidence for its potential as a therapeutic, and provides insight into the mechanisms of tumor suppression through analysis of the target gene regulatory network of miR-497.

Phylogenomics and genetic analysis of solvent-producing Clostridium species.

The genus Clostridium is a large and diverse group within the Bacillota (formerly Firmicutes), whose members can encode useful complex traits such as solvent production, gas-fermentation, and lignocellulose breakdown. We describe 270 genome sequences of solventogenic clostridia from a comprehensive industrial strain collection assembled by Professor David Jones that includes 194 C. beijerinckii, 57 C. saccharobutylicum, 4 C. saccharoperbutylacetonicum, 5 C. butyricum, 7 C. acetobutylicum, and 3 C. tetanomorphum genomes. We report methods, analyses and characterization for phylogeny, key attributes, core biosynthetic genes, secondary metabolites, plasmids, prophage/CRISPR diversity, cellulosomes and quorum sensing for the 6 species. The expanded genomic data described here will facilitate engineering of solvent-producing clostridia as well as non-model microorganisms with innately desirable traits. Sequences could be applied in conventional platform biocatalysts such as yeast or Escherichia coli for enhanced chemical production. Recently, gene sequences from this collection were used to engineer Clostridium autoethanogenum, a gas-fermenting autotrophic acetogen, for continuous acetone or isopropanol production, as well as butanol, butanoic acid, hexanol and hexanoic acid production.

Leading the pack: Best practices in comparative canine cancer genomics to inform human oncology.

Pet dogs develop spontaneous cancers at a rate estimated to be five times higher than that of humans, providing a unique opportunity to study disease biology and evaluate novel therapeutic strategies in a model system that possesses an intact immune system and mirrors key aspects of human cancer biology. Despite decades of interest, effective utilization of pet dog cancers has been hindered by a limited repertoire of necessary cellular and molecular reagents for both in vitro and in vivo studies, as well as a dearth of information regarding the genomic landscape of these cancers. Recently, many of these critical gaps have been addressed through the generation of a highly annotated canine reference genome, the creation of several tools necessary for multi-omic analysis of canine tumours, and the development of a centralized repository for key genomic and associated clinical information from canine cancer patients, the Integrated Canine Data Commons. Together, these advances have catalysed multidisciplinary efforts designed to integrate the study of pet dog cancers more effectively into the translational continuum, with the ultimate goal of improving human outcomes. The current review summarizes this recent progress and provides a guide to resources and tools available for comparative study of pet dog cancers.

Target gene regulatory network of miR-497 in angiosarcoma.

Angiosarcoma (AS) is a vascular sarcoma that is highly aggressive and metastatic. Due to its rarity, treatment options for patients are limited, therefore more research is needed to identify possible therapeutic vulnerabilities. We previously found that conditional deletion of Dicer1 drives AS development in mice. Given the role of DICER1 in canonical microRNA (miRNA) biogenesis, this suggests that miRNA loss is important in AS development. After testing miRNAs previously suggested to have a tumor-suppressive role in AS, microRNA-497-5p (miR-497) suppressed cell viability most significantly. We also found that miR-497 overexpression led to significantly reduced cell migration and tumor formation. To understand the mechanism of miR-497 in tumor suppression, we identified clinically relevant target genes using a combination of RNA-sequencing data in an AS cell line, expression data from AS patients, and target prediction algorithms. We validated miR-497 direct regulation of CCND2, CDK6, and VAT1. One of these genes, VAT1, is an understudied protein that has been suggested to promote cell migration and metastasis in other cancers. Indeed, we find that pharmacologic inhibition of VAT1 with the natural product Neocarzilin A reduces AS migration. This work provides insight into the mechanisms of miR-497 and its target genes in AS pathogenesis.

Draft genome sequence of Rhizobium sp. strain PDO1-076, a bacterium isolated from Populus deltoides.

Rhizobium sp. strain PDO1-076 is a plant-associated bacterium isolated from Populus deltoides, and its draft genome sequence is reported.

Twenty-one genome sequences from Pseudomonas species and 19 genome sequences from diverse bacteria isolated from the rhizosphere and endosphere of Populus deltoides.

To aid in the investigation of the Populus deltoides microbiome, we generated draft genome sequences for 21 Pseudomonas strains and 19 other diverse bacteria isolated from Populus deltoides roots. Genome sequences for isolates similar to Acidovorax, Bradyrhizobium, Brevibacillus, Caulobacter, Chryseobacterium, Flavobacterium, Herbaspirillum, Novosphingobium, Pantoea, Phyllobacterium, Polaromonas, Rhizobium, Sphingobium, and Variovorax were generated.

Draft genome sequence for Microbacterium laevaniformans strain OR221, a bacterium tolerant to metals, nitrate, and low pH.

Microbacterium laevaniformans strain OR221 was isolated from subsurface sediments obtained from the Field Research Center (FRC) in Oak Ridge, TN. It was characterized as a bacterium tolerant to heavy metals, such as uranium, nickel, cobalt, and cadmium, as well as nitrate and low pH. We present its draft genome sequence.

Draft genome sequences for Clostridium thermocellum wild-type strain YS and derived cellulose adhesion-defective mutant strain AD2.

Clostridium thermocellum wild-type strain YS is an anaerobic, thermophilic, cellulolytic bacterium capable of directly converting cellulosic substrates into ethanol. Strain YS and a derived cellulose adhesion-defective mutant strain, AD2, played pivotal roles in describing the original cellulosome concept. We present their draft genome sequences.

Draft genome sequences for two metal-reducing Pelosinus fermentans strains isolated from a Cr(VI)-contaminated site and for type strain R7.

Pelosinus fermentans 16S rRNA gene sequences have been reported from diverse geographical sites since the recent isolation of the type strain. We present the genome sequence of the P. fermentans type strain R7 (DSM 17108) and genome sequences for two new strains with different abilities to reduce iron, chromate, and uranium.

Targeting DNMTs to Overcome Enzalutamide Resistance in Prostate Cancer.

Prostate cancer is the second leading cause of cancer death among men in the United States. The androgen receptor (AR) antagonist enzalutamide is an FDA-approved drug for treatment of patients with late-stage prostate cancer and is currently under clinical study for early-stage prostate cancer treatment. After a short positive response period to enzalutamide, tumors will develop drug resistance. In this study, we uncovered that DNA methylation was deregulated in enzalutamide-resistant cells. DNMT activity and DNMT3B expression were upregulated in resistant cell lines. Enzalutamide induced the expression of DNMT3A and DNMT3B in prostate cancer cells with a potential role of p53 and pRB in this process. The overexpression of DNMT3B3, a DNMT3B variant, promoted an enzalutamide-resistant phenotype in C4-2B cell lines. Inhibition of DNA methylation and DNMT3B knockdown induced a resensitization to enzalutamide. Decitabine treatment in enzalutamide-resistant cells induced a decrease of the expression of AR-V7 and changes of genes for apoptosis, DNA repair, and mRNA splicing. Combination treatment of decitabine and enzalutamide induced a decrease of tumor weight, Ki-67 and AR-V7 expression and an increase of cleaved-caspase3 levels in 22Rv1 xenografts. The collective results suggest that DNA methylation pathway is deregulated after enzalutamide resistance onset and that targeting DNA methyltransferases restores the sensitivity to enzalutamide in prostate cancer cells.

Clostridium autoethanogenum isopropanol production via native plasmid pCA replicon.

Clostridium autoethanogenum is a model gas-fermenting acetogen for commercial ethanol production. It is also a platform organism being developed for the carbon-negative production of acetone and isopropanol by gas fermentation. We have assembled a 5.5 kb pCA plasmid for type strain DSM10061 (JA1-1) using three genome sequence datasets. pCA is predicted to encode seven open-reading frames and estimated to be a low-copy number plasmid present at approximately 12 copies per chromosome. RNA-seq analyses indicate that pCA genes are transcribed at low levels and two proteins, CAETHG_05090 (putative replication protein) and CAETHG_05115 (hypothetical, a possible Mob protein), were detected at low levels during batch gas fermentations. Thiolase (thlA), CoA-transferase (ctfAB), and acetoacetate decarboxylase (adc) genes were introduced into a vector for isopropanol production in C. autoethanogenum using the native plasmid origin of replication. The availability of the pCA sequence will facilitate studies into its physiological role and could form the basis for genetic tool optimization.

Targeting Plk1 Sensitizes Pancreatic Cancer to Immune Checkpoint Therapy.

Polo-like kinase 1 (Plk1) plays an important role in cell-cycle regulation. Recent work has suggested that Plk1 could be a biomarker of gemcitabine response in pancreatic ductal adenocarcinoma (PDAC). Although targeting Plk1 to treat PDAC has been attempted in clinical trials, the results were not promising, and the mechanisms of resistance to Plk1 inhibition is poorly understood. In addition, the role of Plk1 in PDAC progression requires further elucidation. Here, we showed that Plk1 was associated with poor outcomes in patients with PDAC. In an inducible transgenic mouse line with specific expression of Plk1 in the pancreas, Plk1 overexpression significantly inhibited caerulein-induced acute pancreatitis and delayed development of acinar-to-ductal metaplasia and pancreatic intraepithelial neoplasia. Bioinformatics analyses identified the regulatory networks in which Plk1 is involved in PDAC disease progression, including multiple inflammation-related pathways. Unexpectedly, inhibition or depletion of Plk1 resulted in upregulation of PD-L1 via activation of the NF-κB pathway. Mechanistically, Plk1-mediated phosphorylation of RB at S758 inhibited the translocation of NF-κB to nucleus, inactivating the pathway. Inhibition of Plk1 sensitized PDAC to immune checkpoint blockade therapy through activation of an antitumor immune response. Together, Plk1 suppresses PDAC progression and inhibits NF-κB activity, and targeting Plk1 can potentiate the efficacy of immunotherapy in PDAC. SIGNIFICANCE: Inhibition of Plk1 induces upregulation of PD-L1 expression in pancreatic ductal adenocarcinoma, stimulating antitumor immunity and sensitizing tumors to immunotherapy.

Identification of a naturally-occurring canine model for early detection and intervention research in high grade urothelial carcinoma.

Background: Early detection and intervention research is expected to improve the outcomes for patients with high grade muscle invasive urothelial carcinoma (InvUC). With limited patients in suitable high-risk study cohorts, relevant animal model research is critical. Experimental animal models often fail to adequately represent human cancer. The purpose of this study was to determine the suitability of dogs with high breed-associated risk for naturally-occurring InvUC to serve as relevant models for early detection and intervention research. The feasibility of screening and early intervention, and similarities and differences between canine and human tumors, and early and later canine tumors were determined. Methods: STs (n=120) ≥ 6 years old with no outward evidence of urinary disease were screened at 6-month intervals for 3 years with physical exam, ultrasonography, and urinalysis with sediment exam. Cystoscopic biopsy was performed in dogs with positive screening tests. The pathological, clinical, and molecular characteristics of the "early" cancer detected by screening were determined. Transcriptomic signatures were compared between the early tumors and published findings in human InvUC, and to more advanced "later" canine tumors from STs who had the typical presentation of hematuria and urinary dysfunction. An early intervention trial of an oral cyclooxygenase inhibitor, deracoxib, was conducted in dogs with cancer detected through screening. Results: Biopsy-confirmed bladder cancer was detected in 32 (27%) of 120 STs including InvUC (n=29, three starting as dysplasia), grade 1 noninvasive cancer (n=2), and carcinoma in situ (n=1). Transcriptomic signatures including druggable targets such as EGFR and the PI3K-AKT-mTOR pathway, were very similar between canine and human InvUC, especially within luminal and basal molecular subtypes. Marked transcriptomic differences were noted between early and later canine tumors, particularly within luminal subtype tumors. The deracoxib remission rate (42% CR+PR) compared very favorably to that with single-agent cyclooxygenase inhibitors in more advanced canine InvUC (17-25%), supporting the value of early intervention. Conclusions: The study defined a novel naturally-occurring animal model to complement experimental models for early detection and intervention research in InvUC. Research incorporating the canine model is expected to lead to improved outcomes for humans, as well as pet dogs, facing bladder cancer.

Engineering of a functional pancreatic acinus with reprogrammed cancer cells by induced PTF1a expression.

A pancreatic acinus is a functional unit of the exocrine pancreas producing digest enzymes. Its pathobiology is crucial to pancreatic diseases including pancreatitis and pancreatic cancer, which can initiate from pancreatic acini. However, research on pancreatic acini has been significantly hampered due to the difficulty of culturing normal acinar cells in vitro. In this study, an in vitro model of the normal acinus, named pancreatic acinus-on-chip (PAC), is developed using reprogrammed pancreatic cancer cells. The developed model is a microfluidic platform with an epithelial duct and acinar sac geometry microfabricated by a newly developed two-step controlled "viscous-fingering" technique. In this model, human pancreatic cancer cells, Panc-1, reprogrammed to revert to the normal state upon induction of PTF1a gene expression, are cultured. Bioinformatic analyses suggest that, upon induced PTF1a expression, Panc-1 cells transition into a more normal and differentiated acinar phenotype. The microanatomy and exocrine functions of the model are characterized to confirm the normal acinus phenotypes. The developed model provides a new and reliable testbed to study the initiation and progression of pancreatic cancers.