miR-520h is crucial for DAPK2 regulation and breast cancer progression

This corrects the article DOI: 10.1038/onc.2015.168.

miR-520h is crucial for DAPK2 regulation and breast cancer progression

MicroRNAs (miRNAs) are small RNAs that suppress gene expression by their interaction with 3'untranslated region of specific target mRNAs. Although the dysregulation of miRNAs has been identified in human cancer, only a few of these miRNAs have been functionally documented in breast cancer. Thus, defining the important miRNA and functional target involved in chemoresistance is an urgent need for human breast cancer treatment. In this study, we, for the first time, identified a key role of miRNA 520h (miR-520h) in drug resistance. Through protecting cells from paclitaxel-induced apoptosis, expression of miR-520h promoted the drug resistance of human breast cancer cells. Bioinformatics prediction, compensatory mutation and functional validation further confirmed the essential role of miR-520h-suppressed Death-associated protein kinase 2 (DAPK2) expression, as restoring DAPK2 abolished miR-520h-promoted drug resistance, and knockdown of DAPK2 mitigated cell death caused by the depletion of miR-520h. Furthermore, we observed that higher level of miR-520h is associated with poor prognosis and lymph node metastasis in human breast cancer patients. These results show that miR-520h is not only an independent prognostic factor, but is also a potential functional target for future applications in cancer therapeutics.

Stromal fibroblast-derived miR-409 promotes epithelial-to-mesenchymal transition and prostate tumorigenesis

Tumor-stromal interaction is a dynamic process that promotes tumor growth and metastasis via cell-cell interaction and extracellular vesicles. Recent studies demonstrate that stromal fibroblast-derived molecular signatures can be used to predict disease progression and drug resistance. To identify the epigenetic role of stromal noncoding RNAs in tumor-stromal interactions in the tumor microenvironment, we performed microRNA profiling of patient cancer-associated prostate stromal fibroblasts isolated by laser capture dissection microscopy and in bone-associated stromal models. We found specific upregulation of miR-409-3p and miR-409-5p located within the embryonically and developmentally regulated DLK1-DIO3 (delta-like 1 homolog-deiodinase, iodothyronine 3) cluster on human chromosome 14. The findings in cell lines were further validated in human prostate cancer tissues. Strikingly, ectopic expression of miR-409 in normal prostate fibroblasts conferred a cancer-associated stroma-like phenotype and led to the release of miR-409 via extracellular vesicles to promote tumor induction and epithelial-to-mesenchymal transition in vitro and in vivo. miR-409 promoted tumorigenesis through repression of tumor suppressor genes such as Ras suppressor 1 and stromal antigen 2. Thus, stromal fibroblasts derived miR-409-induced tumorigenesis, epithelial-to-mesenchymal transition and stemness of the epithelial cancer cells in vivo. Therefore, miR-409 appears to be an attractive therapeutic target to block the vicious cycle of tumor-stromal interactions that plagues prostate cancer patients.

Long-term proliferation and characterization of human spermatogonial stem cells obtained from obstructive and non-obstructive azoospermia under exogenous feeder-free culture conditions

OBJECTIVES

The aim of the present study was to improve efficiency of isolation and to optimize proliferative potential of human spermatogonial stem cells (SSCs) obtained from obstructive azoospermic (OA) and non-obstructive azoospermic (NOA) patients, and further, to characterize these cells for potential use in infertility treatment or study of reproductive biology.

MATERIALS AND METHODS

We have applied a cell-sorting method, using collagen and magnetic activated cell separation to overcome obstacles, developing a collection system, and simple long-term proliferation system, that yields large numbers of high-purity SSCs from obstructive OA and NOA patients.

RESULTS

SSCs derived from OA and NOA patients proliferated and maintained their characteristics for more than 12 passages (>6 months) in vitro. Moreover, the population of cells positive for the SSC-specific markers GFRalpha-1 and integrin alpha6, increased to more than 80% at passage 8.

CONCLUSION

These finding may support the idea that in vitro propagation of SSCs could be a useful tool for infertility treatment and study of reproductive biology.

An orally active cathepsin K inhibitor, furan-2-carboxylic acid, 1-{1-[4-fluoro-2-(2-oxo-pyrrolidin-1-yl)-phenyl]-3-oxo-piperidin-4-ylcarbamoyl}-cyclohexyl)-amide (OST-4077), inhibits osteoclast activity in vitro and bone loss in ovariectomized rats

Human cathepsin K, a cysteine proteinase of the papain family, has been recognized as a potential drug target for the treatment of osteoporosis. The predominant expression of cathepsin K in osteoclasts has rendered the enzyme into a major target for the development of novel antiresorptive drugs. Now, we report the pharmacological properties of OST-4077 [furan-2-carboxylic acid (1-{1-[4-fluoro-2-(2-oxo-pyrrolidin-1-yl)-phenyl]-3-oxo-piperidin-4-ylcarbamoyl}-cyclohexyl)-amide] as a novel selective cathepsin K inhibitor. Human and rat cathepsin K were inhibited in vitro by OST-4077 with the IC50 values of 11 and 427 nM, respectively. OST-4077 suppressed bone resorption induced by rabbit osteoclasts (IC50, 37 nM) but did not affect bone mineralization or cellular alkaline phosphatase activity in MC3T3-E1 cells. Parathyroid hormone-induced bone resorption was inhibited in a dose-dependent manner in thyroparathyroidectomized rats gavaged with a single dose of OST-4077 (ED50, 69 mg/kg). When given orally twice daily for 4 weeks to 3-month-old ovariectomized (OVX) rats, OST-4077 dose-dependently prevented bone loss, as monitored by bone densitometry, ash content, and urinary excretion of deoxypyridinoline. No change in serum osteocalcin in the OVX rats by OST-4077 suggested that bone formation might not be affected by the agent. In summary, OST-4077 selectively inhibited bone resorbing activities of osteoclasts and prevented bone loss induced by estrogen deficiency but did not affect bone formation. OST-4077, an orally active selective human cathepsin K inhibitor, may have the therapeutic potential for the treatment of diseases characterized by excessive bone loss including osteoporosis.

Evidence for the contribution of point mutations to vlsE variation and for apparent constraints on the net accumulation of sequence changes in vlsE during infection with Lyme disease spirochetes

In the Lyme disease spirochetes, both the ospE and vlsE gene families have been demonstrated to undergo sequence variation during infection. To further investigate the mechanisms associated with the generation of vls variation, single-nucleotide polymorphism and subsequent DNA sequence analyses were performed on the vlsE gene and its paralog, BBJ51, a related gene with a frameshift mutation. These analyses focused on a series of postinfection clonal populations obtained from mice infected with Borrelia burgdorferi B31MIpc or its clonal derivative, B31MIc53. vlsE, but not BBJ51, was found to undergo sequence changes during infection. Consistent with that reported previously (J.-R. Zhang et al., Cell 89:275-285, 1997) many of the sequence changes appear to have arisen through gene conversion events and to be localized to the variable regions of vlsE. However, analysis of the vlsE nucleotide sequences revealed that some sequence changes were the result of point mutations, as these changes did not have potential contributing sources in the vls cassettes. To determine if sequence changes accumulate in vlsE over long-term infection, the vlsE genes of clonal populations recovered after 7 months of infection in mice were analyzed. While new sequence changes developed, a significant number of these changes resulted in the restoration of the vlsE sequence of the original infecting clone. In addition, we noted that some positions within the variable regions (VR) are stable even though the cassettes possess residues that could contribute to sequence variation through gene conversion. These analyses suggest that the total number of amino acid sequence changes that can be maintained by VlsE levels off during infection. In summary, in this report we demonstrate that the development of point mutations serves as a second mechanism by which vlsE sequence variation can be generated and that the capacity for vlsE variation, while still significant, is less than previously postulated.

Demonstration of the genetic stability and temporal expression of select members of the lyme disease spirochete OspF protein family during infection in mice

Infection with Lyme disease spirochetes can be chronic. This suggests that the spirochetes are capable of immune evasion. In a previous study we demonstrated that the ospE gene family, which is one of three gene families whose members are flanked at their 5' end by the highly conserved upstream homology box (UHB) element, undergoes mutation and rearrangement during infection. This results in the generation of antigenically distinct variants that may contribute to immune evasion. In this study we have assessed the genetic stability of the UHB-flanked ospF gene family during infection in mice. Using postinfection clonal populations of Borrelia burgdorferi B31MI, PCR amplicons were generated for three members of the ospF gene family after a 3-month infection time frame. The amplicons were analyzed by single-nucleotide polymorphism pattern analysis and DNA sequencing. Members of the ospF gene family were found to be stable during infection, as no mutations or rearrangements were detected. An analysis of the humoral immune response to these proteins during infection revealed that the immune response to each is specific and that there is a delayed humoral immune response to some OspF protein family members. These analyses suggest that there is a temporal component to the expression of these genes during infection. In addition to a possible contribution to immune evasion, members of the OspF protein family may play specific roles at different stages of infection.

Analysis of mechanisms associated with loss of infectivity of clonal populations of Borrelia burgdorferi B31MI

Numerous studies have provided suggestive evidence that the loss of plasmids correlates with the loss of infectivity of the Lyme disease spirochetes. In this study we have further investigated this correlation. Clonal populations were obtained from the skin of a mouse infected for 3 months with a clonal population of Borrelia burgdorferi B31MI. The complete plasmid compositions of these populations were determined using a combination of PCR and Southern hybridization. The infectivities of clones differing in plasmid composition were tested using the C3H-HeJ murine model for Lyme disease. While several clones were found to be noninfectious, a correlation between the loss of a specific plasmid and loss of infectivity in the clones analyzed in this report was not observed. While it is clear from recent studies that the loss of some specific plasmids results in attenuated virulence, this study demonstrates that additional mechanisms also contribute to the loss of infectivity.

Mutation and recombination in the upstream homology box-flanked ospE-related genes of the Lyme disease spirochetes result in the development of new antigenic variants during infection

The ospE gene family of the Lyme disease spirochetes encodes a polymorphic group of immunogenic lipoproteins. The ospE genes are one of several gene families that are flanked by a highly conserved upstream sequence called the upstream homology box, or UHB, element. Earlier analyses in our lab demonstrated that ospE-related genes are characterized by defined hypervariable domains (domains 1 and 2) that are predicted to be hydrophilic, surface exposed, and antigenic. The flanking of hypervariable domain 1 by DNA repeats may indicate that recombination contributes to ospE diversity and thus ultimately to antigenic variation. Using an isogeneic clone of Borrelia burgdorferi B31G (designated B31Gc1), we demonstrate that the ospE-related genes undergo mutation and rearrangement during infection in mice. The mutations that develop during infection resulted in the generation of OspE proteins with altered antigenic characteristics. The data support the hypothesized role of OspE-related proteins in immune system evasion.

Genetic divergence and evolutionary instability in ospE-related members of the upstream homology box gene family in Borrelia burgdorferi sensu lato complex isolates

A series of related genes that are flanked at their 5' ends by a conserved upstream sequence element called the upstream homology box (UHB) have been identified in Borrelia burgdorferi. These genes have been referred to as the UHB or erp gene family. We previously demonstrated that among a limited number of B. burgdorferi isolates, the UHB gene family is variable in composition and organization. Prior to this report the UHB gene family in other species of the B. burgdorferi sensu lato complex had not been studied, and if this family is important in the pathogenesis or biology of the Lyme disease spirochetes, then a wide distribution among species and isolates of the B. burgdorferi sensu lato complex would be expected. To assess this, we screened for the UHB element by Southern hybridization and determined its restriction fragment length polymorphism (RFLP) patterns. The UHB element was found to be carried by all B. burgdorferi sensu lato complex species tested (B. burgdorferi, B. garinii, B. afzelii, B. japonica, B. valaisiana sp. nov., and B. andersonii), but the RFLP patterns varied widely at both the inter- and intraspecies levels. Variation in both the number and size of the hybridizing restriction fragments was evident. PCR analyses also revealed the presence of polymorphic, ospE-related alleles in many isolates. Sequence analyses identified the molecular basis of the polymorphisms as being primarily insertions and deletions. Sequence variation and the insertions and deletions were found to be clustered in two distinct domains (variable domains 1 and 2). In many isolates variable domain 1 is flanked by direct repeat elements, some as long as 38 bp. Computer analyses of the deduced amino acid sequences encoded within variable domain 1 predict them to be hydrophilic, surface exposed, and antigenic. The analyses conducted here suggest that the UHB gene family, as evidenced by the variable UHB RFLP patterns, is not evolutionarily stable and that the polymorphic ospE alleles are derived from a common ancestral gene which has been modified through mutation or recombination events. The characterization of ospE-related genes of the UHB gene family among B. burgdorferi sensu lato species will prove important in attempts to construct a model for UHB gene family organization and in deciphering the role of the UHB gene family in the biology and pathogenesis of the Lyme disease spirochetes.

Synthesis of the 7,8-dihydro-7-deazapurine derivatives and their antibiotic activity

The cis- and trans-diastereomers of the 7,8-dihydro-7-deazapurine derivatives were synthesized from the corresponding diastereomers of 4-trans-cyano-2-methyl-3-phenyl-5-oxopyrrolidine (5), which were reduced from the 2-cis- and 2-trans-diastereomers of 4-trans-cyano-2-hydroxymethyl-3-phenyl-5-oxopyrrolidine (2) via tosylation, iodination and following elimination, respectively. The prepared cis- and trans-diastereomers of 6-amino-2-mercapto-8-methyl-7-phenyl-7,8-dihydro-7(9H)-deazapurine (8) were transferred to the corresponding 2-methylthio-diastereomers 9 and following desulfurization with Raney-nickel leaded to the cis- and trans-diastereomers of 6-amino-8-methyl-7-phenyl-7,8-dihydro-7(9H)-deazapurine (10), respectively. The synthesized 7-deazapurine derivatives were tested for their antibiotic activity by the serial two-fold dilution method.

Analysis of the organization of multicopy linear- and circular-plasmid-carried open reading frames in Borrelia burgdorferi sensu lato isolates

Plasmid cp8.3 of Borrelia afzelii IP21 carries several open reading frames (ORFs) and a 184-bp inverted repeat (IR) element. It has been speculated that this plasmid may encode factors involved in virulence or infectivity. In this report, we have characterized the distribution, molecular variability, and organization of ORFs 1, 2, and 4 and the IR elements among isolates of the Borrelia burgdorferi sensu lato complex. ORFs 1 and 2 are contained within a segment of cp8.3 that is bordered by the IR elements, while ORF 4 resides just outside of the IR-bordered region. By PCR, ORF 4 was amplified from most isolates while ORFs 1 and 2 were amplified from only some B. afzelii isolates. However, Southern hybridization analyses with ORF 1, 2, and 4 probes detected related sequences even in some isolates that were PCR negative. The ORF restriction fragment length polymorphism patterns varied widely even among isolates of the same species. Two-dimensional contour-clamped homogeneous electric field-pulsed-field gel electrophoresis and Southern hybridization detected ORF 1-, 2-, and 4-related sequences on linear and circular plasmids. In addition, an ORF 4-related sequence was detected on a previously uncharacterized, circular plasmid that is greater than 70 kb in size. The IR elements originally identified on plasmid cp8.3 of B. afzelii IP21 were also analyzed by Southern hybridization. Related sequences were detected in some but not all B. burgdorferi sensu lato isolates. These sequences are carried on plasmids in addition to cp8.3 in some isolates. Single-primer PCR analyses demonstrated that in some isolates these sequences exist with IR orientation. The data presented here demonstrate that the IR elements and the ORF 1-, 2-, and 4-related sequences are multicopy and are variable in organization and in genomic location among isolates of the B. burgdorferi sensu lato complex. These analyses provide additional evidence for the highly variable organization of the plasmid component of the B. burgdorferi sensu lato genome.

Asymmetric synthesis and structure-activity relationship of the four stereoisomers of the antibiotic amidinomycin. Part 2: Microbiological testing

The stereoisomers of amidinomycin 7 and their intermediates 1-6, which are produced from homochiral 3-oxocyclopentanecarboxylic acids by asymmetric synthesis, are tested for their antimicrobial effects by agar diffusion test and by Bouillon serial dilution assay. Their antibiotic activities against Bacillus subtilis, Staphylococcus aureus, and Micrococcus Iuteus, respectively, are reported. Structure-activity relationships depend on the type and combination of functional groups, on only the relative stereochemistry as well as on the grade of lipophilia of the tested compounds.

Bowenoid epidermotropic metastatic squamous cell carcinoma

Epidermotropic metastatic squamous cell carcinoma produced full-thickness cellular atypia of bowenoid carcinoma in situ or vulvar intraepithelial neoplasia, grade 3 (VIN 3), in a 73-year-old woman who had past history of uterine cervical carcinoma. The presence of intravascular tumor cell nests and areas showing smooth continuity of the malignant squamous cell nodules with the adjoining benign epidermis supported the possibility of the epidermotropic metastasis. To our knowledge, metastatic epidermotropic squamous carcinoma clinicopathologically simulating primary Bowen's disease has not been reported.

Molecular and evolutionary analyses of a variable series of genes in Borrelia burgdorferi that are related to ospE and ospF, constitute a gene family, and share a common upstream homology box

In this study we report on the molecular characterization of a series of genes that constitute a gene family related to ospE and ospF. Some members of this family appear to represent recombined or variant forms of ospE and ospF. Variant ospE and ospF genes were found in several Borrelia burgdorferi isolates, demonstrating that their occurrence is not a phenomenon relevant to only a single isolate. Hybridization analyses revealed that the upstream sequence originally identified 5' of the full-length ospEF operon exists in multiple copies ranging in number from two to six depending on the isolate. This repeated sequence, which we refer to as the upstream homology box (UHB), carries a putative promoter element. In some isolates, UHB elements were found to flank copies of ospE and ospF that exist independently of each other. We refer to this group of UHB-flanked genes collectively as the UHB gene family. The evolutionary relationships among UHB gene family members were assessed through DNA sequence analysis and gene tree construction. These analyses suggest that some UHB-flanked genes might actually represent divergent forms of other previously described genes. Analysis of the restriction fragment length polymorphism patterns of the UHB-flanked genes among B. burgdorferi isolates demonstrated that these patterns are highly variable among isolates, suggesting that these genes are not phylogenetically conserved. The variable restriction fragment length polymorphism patterns could indicate recombinational activity in these sequences. The presence of numerous copies of the UHB elements and the high degree of homology among UHB-flanked genes could provide the necessary elements to allow for homologous recombination, leading to the generation of recombination variants of UHB gene family members.

N-linked glycosylation of hepatitis B surface antigens is involved but not essential in the assembly of hepatitis delta virus

Hepatitis delta virus (HDV) is a defective virus requiring the hepatitis B virus (HBV) to provide hepatitis B surface antigens as the envelope protein. The hepatitis B surface antigens are posttranslationally modified by N-linked glycosylation, and its significance in HDV assembly was investigated with a cotransfection system using human hepatoma cell line Huh-7. After the N-linked glycosylation of HBsAg was blocked by tunicamycin treatment, the packaging of HDV in the culture system could be suppressed to a level as low as 5-10% of the untreated control. The extent of inhibition correlated with the increased concentrations of tunicamycin. In contrast, the loss of HBsAg glycosylation did not affect the efficiency of assembly of HBV particles. When the N-linked glycosylation site of small HBsAg at amino acid 146 was mutated from asparagine to glutamine, the mutant HBsAg packaged only a modest amount of HDV particles. The quantity and kinetics of formation of HDV particles in culture system were reduced by the depletion of HBsAg glycosylation. Therefore HDV, similar to influenza and vesicular stomatitis viruses, depends on glycosylation of the envelope proteins as a signal for envelope protein maturation and for virion formation.

Cyclooxygenase inhibitors blunt thromboxane action in human placental arteries by blocking thromboxane receptors

The effects of cyclooxygenase inhibitors on thromboxane-mediated vasoconstriction in human placental arteries were studied in the isolated perfused fetoplacental cotyledon. The stable thromboxane agonist U-46619 caused a dose-related increase in perfusion pressure in the fetal side of the cotyledon. Meclofenamate (3.3 x 10(-5) M) significantly blunted the pressor response to U-46619, but not to angiotensin II, and inhibited thromboxane B2 formation in placental slices (IC50, 4.80 x 10(-8) M). The mechanism by which meclofenamate prevented thromboxane-induced vasoconstriction was studied using ligand-binding techniques in a membrane fraction prepared from placental cotyledons. Meclofenamate caused a dose-related inhibition of binding of the thromboxane receptor antagonist [3H]SQ 29548 with an IC50 of 2.61 x 10(-5) M. Scatchard analysis of equilibrium binding demonstrated that meclofenamate reduced the number of binding sites without altering the affinity of the receptor, suggesting a noncompetitive mechanism. Indomethacin also caused a dose-related inhibition of thromboxane binding (IC50, 3.27 x 10(-4) M). However, aspirin at a dose of 2.0 x 10(-3) M did not inhibit [3H]SQ 29548 binding. The data indicate that some cyclooxygenase inhibitors blunt thromboxane actions by interfering with binding at thromboxane receptor sites. These studies identify a new mechanism by which cyclooxygenase inhibition by some nonsteroidal anti-inflammatory drugs can prevent thromboxane action in fetoplacental blood vessels in vitro independent of reductions in thromboxane formation.

Functional study of hepatitis delta virus large antigen in packaging and replication inhibition: role of the amino-terminal leucine zipper

The large hepatitis delta antigen (HDAg) has been found to be essential for the assembly of the hepatitis delta virion. Furthermore, in a cotransfection experiment, the large HDAg itself, without the hepatitis delta virus (HDV) genome and small HDAg, could be packaged into hepatitis B surface antigen (HBsAg) particles. By deletion analysis, it was shown that the amino-terminal leucine zipper domain was dispensable for packaging. The large HDAg could also help in copackaging of the small HDAg into HBsAg particles without the need for HDV RNA. This process was probably mediated through direct interaction of the two HDAgs as a mutated large HDAg whose leucine zipper domain was deleted such that it could not help in copackaging of the small HDAg. This mutated large HDAg did not suppress HDV replication, suggesting that this effect is probably also via protein interaction. These results indicated that functional domains of the large HDAg responsible for packaging with HBsAg particles and for the trans-negative effect on HDV replication can be separated.