Prostate cancer remains the second leading cause of cancer death in American men and there is an unmet need for biomarkers to identify patients with aggressive disease. In an effort to identify biomarkers of recurrence, we performed global RNA sequencing on 106 formalin-fixed, paraffin-embedded (FFPE) prostatectomy samples from 100 patients at three independent sites, defining a 24-gene signature panel. The 24 genes in this panel function in cell cycle progression, angiogenesis, hypoxia, apoptosis, PI3K signaling, steroid metabolism, translation, chromatin modification and transcription. Sixteen genes have been associated with cancer with five specifically associated with prostate cancer (BTG2, IGFBP3, SIRT1, MXI1 and FDPS). Validation was performed on an independent publicly available dataset of 140 patients, where the new signature panel outperformed markers published previously in terms of predicting biochemical recurrence (BCR). Our work also identified differences in gene expression between Gleason Pattern 4+3 and 3+4 tumors, including several genes involved in the epithelial to mesenchymal transition and developmental pathways. Overall, this study defines a novel biomarker panel that has the potential to improve the clinical management of prostate cancer.
Understanding remains incomplete of the mechanisms underlying initiation and progression of prostate cancer, the most commonly diagnosed cancer in American men. The transcription factor SOX4 is overexpressed in many human cancers, including prostate cancer, suggesting it may participate in prostate tumorigenesis. In this study, we investigated this possibility by genetically deleting Sox4 in a mouse model of prostate cancer initiated by loss of the tumor suppressor Pten. We found that specific homozygous deletion of Sox4 in the adult prostate epithelium strongly inhibited tumor progression initiated by homozygous loss of Pten. Mechanistically, Sox4 ablation reduced activation of AKT and β-catenin, leading to an attenuated invasive phenotype. Furthermore, SOX4 expression was induced by Pten loss as a result of the activation of PI3K-AKT-mTOR signaling, suggesting a positive feedback loop between SOX4 and PI3K-AKT-mTOR activity. Collectively, our findings establish that SOX4 is a critical component of the PTEN-PI3K-AKT pathway in prostate cancer, with potential implications for combination targeted therapies against both primary and advanced prostate cancers.
Neisseria meningitidis employs redundant heme acquisition mechanisms, including TonB receptor-dependent and receptorindependent uptakes. The TonB-dependent zinc receptor ZnuD shares significant sequence similarity to HumA, a heme receptor of Moraxella catarrhalis, and contains conserved motifs found in many heme utilization proteins. We present data showing that, when expressed in Escherichia coli, ZnuD allowed heme capture on the cell surface and supported the heme-dependent growth of an E. coli hemA strain. Heme agarose captured ZnuD in enriched outer membrane fractions, and this binding was inhibited by excess free heme, supporting ZnuD's specific interaction with heme. However, no heme utilization defect was detected in the meningococcal znuD mutant, likely due to unknown redundant TonB-independent heme uptake mechanisms. Meningococcal replication within epithelial cells requires a functional TonB, and we found that both the znuD and tonB mutants were defective not only in survival within epithelial cells but also in adherence to and invasion of epithelial cells. Ectopic complementation rescued these phenotypes. Interestingly, while znuD expression was repressed by Zur with zinc as a cofactor, it also was induced by iron in a Zur-independent manner. A specific interaction of meningococcal Fur protein with the znuD promoter was demonstrated by electrophoretic mobility shift assay (EMSA). Thus, the meningococcal ZnuD receptor likely participates in both zinc and heme acquisition, is regulated by both Zur and Fur, and is important for meningococcal interaction with epithelial cells.
Proper periplasmic disulfide bond formation is important for folding and stability of many secreted and membrane proteins, and is catalyzed by three DsbA oxidoreductases in Neisseria meningitidis. DsbD provides reducing power to DsbC that shuffles incorrect disulfide bond in misfolded proteins as well as to the periplasmic enzymes that reduce apo-cytochrome c (CcsX) or repair oxidative protein damages (MrsAB). The expression of dsbD, but not other dsb genes, is positively regulated by the MisR/S two-component system. qRT-PCR analyses showed significantly reduced dsbD expression in all misR/S mutants, which was rescued by genetic complementation. The direct and specific interaction of MisR with the upstream region of the dsbD promoter was demonstrated by EMSA, and the MisR-binding sequences were mapped. Further, the expression of dsbD was found to be induced by dithiothrietol (DTT), through the MisR/S regulatory system. Surprisingly, we revealed that inactivation of dsbD can only be achieved in a strain carrying an ectopically located dsbD, in the dsbA1A2 double mutant or in the dsbA1A2A3 triple mutant, thus DsbD is indispensable for DsbA-catalyzed oxidative protein folding in N. meningitidis. The defects of the meningococcal dsbA1A2 mutant in transformation and resistance to oxidative stress were more severe in the absence of dsbD.
BACKGROUND:Stressors affect populations exposed to them as well as offspring. Strategies preventing the intergenerational propagation of effects of stress would benefit public health. Olfactory cue-based fear conditioning provides a framework to address this issue. METHODS:We 1) exposed adult male mice to an odor, acetophenone (Ace) or Lyral (parental generation [F0]-Exposed), 2) trained mice to associate these odors with mild foot shocks (F0-Trained), and 3) trained mice to associate these odors with mild foot shocks and then extinguished their fear toward these odors with odor-only presentations (F0-Extinguished). We then examined sensitivity of future generation (F1) offspring to these odors, expression of M71 odorant (Aceresponsive) and MOR23 odorant (Lyral-responsive) receptor-expressing cell populations in F1 offspring, and DNA methylation at genes encoding the Ace-(Olfr151, Olfr160) and Lyral-(Olfr16) responsive receptors in F0 sperm. RESULTS:Extinguishing fear toward Ace or Lyral of F0 male mice (F0-Extinguished) that had been fear conditioned with Ace or Lyral, respectively, results in F1-Extinguished offspring that do not demonstrate behavioral sensitivity to Ace or Lyral, respectively, and do not have enhanced representation for M71 or MOR23 odorant receptors in the olfactory system, as is observed in F1-Trained-Ace or F1-Trained-Lyral cohorts, respectively. The promoters of genes encoding Olfr151 and Olfr160 receptors are less methylated in F0-Trained-Ace sperm compared with F0-Exposed-Ace sperm. The Olfr16 promoter is less methylated in F0-Trained-Lyral sperm compared with F0-Exposed-Lyral sperm, and F0Extinguished-Lyral sperm have methylation levels comparable to F0-Exposed-Lyral sperm. CONCLUSIONS:Our study demonstrates the potential of using extinction-based behavioral strategies to reverse influences of parental stress in offspring and in the parental germline.
Outer membrane iron receptors are some of the major surface entities that are critical for meningococcal pathogenesis. The gene encoding the meningococcal hemoglobin receptor, HmbR, is both independently transcribed and transcriptionally linked to the upstream gene hemO, which encodes a heme oxygenase. The MisR/S two-component system was previously determined to regulate hmbR transcription, and its hemO and hmbR regulatory mechanisms were characterized further here. The expression of hemO and hmbR was downregulated in misR/S mutants under both iron-replete and iron-restricted conditions, and the downregulation could be reversed by complementation. No significant changes in expression of other iron receptors were detected, suggesting that the MisR/S system specifically regulates hmbR. When hemoglobin was the sole iron source, growth defects were detected in the mutants. Primer extension analysis identified a promoter upstream of the hemO-associated Correia element (CE) and another promoter at the proximal end of CE, and processed transcripts previously identified for other cotranscribed CEs were also detected, suggesting that there may be posttranscriptional regulation. MisR directly interacts with sequences upstream of the CE and upstream of the hmbR Fur binding site and thus independently regulates hemO and hmbR. Analysis of transcriptional reporters of hemO and hmbR further demonstrated the positive role of the MisR/S system and showed that the transcription of hmbR initiated from hemO was significantly reduced. A comparison of the effects of the misS mutation under iron-replete and iron-depleted conditions suggested that activation by the MisR/S system and iron-mediated repression by Fur act independently. Thus, the expression of hemO and hmbR is coordinately controlled by multiple independent regulatory mechanisms, including the MisR/S two-component system.
Salient sensory environments experienced by a parental generation can exert intergenerational influences on offspring. While these data provide an exciting new perspective on biological inheritance, questions remain about causes and consequences of intergenerational influences of salient sensory experience. We previously showed that exposing male mice to a salient olfactory experience, like olfactory fear conditioning, resulted in offspring demonstrating a sensitivity to the odor used to condition the paternal generation and possessing enhanced neuroanatomical representation for that odor. In this study, we first injected RNA extracted from sperm of male mice that underwent olfactory fear conditioning into naïve single‐cell zygotes and found that adults that developed from these embryos had increased sensitivity and enhanced neuroanatomical representation for the odor (Odor A) with which the paternal male had been conditioned. Next, we found that female, but not male offspring sired by males conditioned with Odor A show enhanced consolidation of a weak single‐trial Odor A + shock fear conditioning protocol. Our data provide evidence that RNA found in the paternal germline after exposure to salient sensory experiences can contribute to intergenerational influences of such experiences, and that such intergenerational influences confer an element of adaptation to the offspring. In so doing, our study of intergenerational influences of parental sensory experience adds to existing literature on intergenerational influences of parental exposures to stress and dietary manipulations and suggests that some causes (sperm RNA) and consequences (behavioral flexibility) of intergenerational influences of parental experiences may be conserved across a variety of parental experiences.
Neisseria meningitidis, an obligate human pathogen, remains a leading cause of meningitis and fatal sepsis. Meningococci are known to secrete a family of proteins, such as FrpC, with sequence similarity to the repeat-in-toxin (RTX) proteins via the type I secretion system. The meningococcal type I secretion proteins are encoded at two distant genetic loci, NMB1400 (hlyB) and NMB1738/1737 (hlyD/tolC), and are separated from the RTX toxin-like substrates. We have characterized the promoter elements of both hlyB and hlyD by primer extension and lacZ reporter fusions and revealed the growth phase-dependent upregulation of both genes. In addition, we showed that the MisR/MisS two-component system negatively regulates the expression of hlyB and hlyD/tolC. Direct binding of MisR to hlyB and hlyD promoters was demonstrated by electrophoretic mobility shift assay (EMSA), and DNase I protection assays identified MisR binding sites overlapping the promoter elements. Direct repression of hlyB transcription by MisR was supported by in vitro transcription assays. Mutations in the MisR/S system affected, but did not eliminate, the growth phase-dependent upregulation of hlyB, suggesting additional regulatory mechanisms. Increased secretion of RTX toxin-like proteins was detected in the cell-free media from misS mutant cultures, indicating that the amounts of extracellular RTX toxin-like proteins are, in part, controlled by the abundance of the type I secretion apparatus. This is, to our knowledge, the first example of a two-component system mediating secretion of cytotoxin family proteins by controlling expression of the type I secretion proteins.
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