Involvement of miR-30c in resistance to doxorubicin by regulating YWHAZ in breast cancer cells

MicroRNAs (miRNAs) are small RNA molecules that modulate gene expression implicated in cancer, which play crucial roles in diverse biological processes, such as development, differentiation, apoptosis, and proliferation. The aim of this study was to investigate whether miR-30c mediated the resistance of breast cancer cells to the chemotherapeutic agent doxorubicin (ADR) by targeting tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ). miR-30c was downregulated in the doxorubicin-resistant human breast cancer cell lines MCF-7/ADR and MDA-MB-231/ADR compared with their parental MCF-7 and MDA-MB-231 cell lines, respectively. Furthermore, we observed that transfection of an miR-30c mimic significantly suppressed the ability of MCF-7/ADR to resist doxorubicin. Moreover, the anti-apoptotic gene YWHAZ was confirmed as a target of miR-30c by luciferase reporter assay, and further studies indicated that the mechanism for miR-30c on the sensitivity of breast cancer cells involved YWHAZ and its downstream p38 mitogen-activated protein kinase (p38MAPK) pathway. Together, our findings provided evidence that miR-30c was one of the important miRNAs in doxorubicin resistance by regulating YWHAZ in the breast cancer cell line MCF-7/ADR.

HLA-DR3 antigen in the resistance to idiopathic dilated cardiomyopathy

Idiopathic dilated cardiomyopathy (IDC) has been hypothesized as a multifactorial disorder initiated by an environment trigger in individuals with predisposing human leukocyte antigen (HLA) alleles. Published data on the association between HLA-DR3 antigen and IDC risk are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. Studies were identified by searching the PUBMED and Embase database (starting from June 2015). A total of 19 case-control studies including 1378 cases and 10383 controls provided data on the association between HLA-DR3 antigen and genetic susceptibility to IDC. Overall, significantly decreased frequency of HLA-DR3 allele (OR=0.72; 95%CI=0.58-0.90; P=0.004) was found in patients with IDC compared with controls. When stratified by myocardial biopsy or non-biopsy cases, statistically decreased risk was found for IDC in myocardial biopsy cases (OR=0.69; 95%CI=0.57-0.84; P=0.0003). In the subgroup analysis by ethnicity, borderline statistically significantly decreased risk was found among Europeans from 12 case-control studies (OR=0.76; 95%CI=0.58-1.00; P=0.05). In conclusion, our results suggest that individuals with HLA-DR3 antigen may have a protective effect against IDC.

Incidence of resistance to benzimidazole fungicides in a field population of Venturia inaequalis /

The allele-specific polymerase chain reaction (PCR) was used to screen for the presence of benomyl resistance, and to characterize their levels and frequencies in field populations of Venturia inaequalis during two seasons. Three hundred isolates of V. inaequalis were collected each season from infected leaves of MalusX domestica. Borkh c.v. Mcintosh. The trees used were sprayed in the year prior to collection with five applications of benomyl, its homologue Azindoyle, or water. Monoconidial isolates of V. inaequalis were grown on 2% potato dextrose agar (PDA) for four weeks. Each isolate was taken from a single lesion from a single leaf. Total genomic DNA was extracted from the four week old colonies of V. inaequalis, prepared and used as a template in PCR reactions. PCR reactions were achieved by utilizing allele-specific primers. Each primer was designed to amplify fragments from a specific allele. Primer Vin was specific for mutations conferring the ben^^"^ phenotype. It was expected to amplify a 171 bp. DNA fragment from the ben^"^ alleles only. Primers BenHR and BenMR were specific for mutations conferring the ben"" and ben'^'' phenotypes, respectively. They were expected to amplify 172 bp. and 165 bp. DNA fragments from the ben"" and ben"^" alleles, respectively. Of the 953 isolates tested, 414 (69.9%) were benomyl sensitive (ben^) and 179 (30.1%) were benomyl resistant. All the benomyl resistant alleles were ben^"", since neither the ben"" nor the ben"" alleles were detected. Frequencies of benomyl resistance were 23%, 24%, and 23% for the 1997 collections, and were 46%, 26% and 38% for the 1998 collections for benomyl, Azindoyle and water treatments, respectively. Growth assay was performed to evaluate the applicability of using PCR in monitoring benomyl resistance in fungal field populations. Tests were performed on 14 isolates representing the two phenotypes (ben^ and ben^"'' alleles) characterized by PCR. Results of those tests were in agreement with PCR results. Enzyme digestion was also used to evaluate the accuracy and reliability of PCR products. The mutation associated with the ben^"'' phenotype creates a unique site for the endonuclease enzyme Bsh^236^ allowing the use of enzyme digestion. Isolates characterized by PCR as ben^'^'^ alleles had this restriction site for the SsA7l2361 enzyme. The most time consuming aspect of this study was growing fungal isolates on culture media for DNA extraction. In addition, the risk of contamination or losing the fungus during growth processes was relatively high. A technique for extracting DNA directly from lesions on leaves has been used (Luck and Gillings 1 995). In order to apply this technique in experiments designed to monitor fungicide resistance, a lesion has to be homogeneous for fungicide sensitivity. For this purpose, PCR protocol was used to determine lesion homogeneity. One hundred monoconidial isolates of V. inaequalis from 10 lesions (10-conidia/ lesion) were tested for their phenotypes with respect to benomyl sensitivity. Conidia of six lesions were homogeneous, while conidia of the remaining lesions were mixtures of ben^ and ben^ phenotypes. Neither the ben" nor the ben' phenotype was detected.

Role of Exopolysaccharides and Monosaccharides in Erwinia amylovora Resistance to Bacteriophages

Fire blight is a disease caused by the phytopathogenic bacterium Erwinia amylovora, an economically important pathogen in the commercial production of apples and pears. Bacteriophages have been proposed as a commercial biopesticide to relieve the pressures on apple and pear production and provide alternatives to existing biological control options. This work reports on the investigation of host resistance in the development of a phage biopesticide. Exopolysaccharide (EPS) deficient bacterial mutants were generated through recombineering to investigate the role of EPS in bacteriophage adsorption and infection. The mutants that were deficient in amylovoran production were avirulent and resistant to infection by phages of the Podoviridae and some of the Siphoviridae family. Levan deficient bacterial mutants resulted in reduced phage titers in some phages from the Myoviridae family. Exopolysaccharide mimetic monosaccharides were used to demonstrate that levan and amylovoran play an important role in phage attack of E. amylovora.

An update of the mechanisms of resistance to EGFR-tyrosine kinase inhibitors in breast cancer: gefitinib (Iressatrade mark)-induced changes in the expression and nucleo-cytoplasmic trafficking of HER-ligands (Review)

Intrinsic resistance to the epidermal growth factor receptor (EGFR; HER1) tyrosine kinase inhibitor (TKI) gefitinib, and more generally to EGFR TKIs, is a common phenomenon in breast cancer. The availability of molecular criteria for predicting sensitivity to EGFR-TKIs is, therefore, the most relevant issue for their correct use and for planning future research. Though it appears that in non-small-cell lung cancer (NSCLC) response to gefitinib is directly related to the occurrence of specific mutations in the EGFR TK domain, breast cancer patients cannot be selected for treatment with gefitinib on the same basis as such EGFR mutations have been reported neither in primary breast carcinomas nor in several breast cancer cell lines. Alternatively, there is a general agreement on the hypothesis that the occurrence of molecular alterations that activate transduction pathways downstream of EGFR (i.e., MEK1/MEK2 - ERK1/2 MAPK and PI-3'K - AKT growth/survival signaling cascades) significantly affect the response to EGFR TKIs in breast carcinomas. However, there are no studies so far addressing a role of EGF-related ligands as intrinsic breast cancer cell modulators of EGFR TKI efficacy. We recently monitored gene expression profiles and sub-cellular localization of HER-1/-2/-3/-4 related ligands (i.e., EGF, amphiregulin, transforming growth factor-α, ß-cellulin, epiregulin and neuregulins) prior to and after gefitinib treatment in a panel of human breast cancer cell lines. First, gefitinibinduced changes in the endogenous levels of EGF-related ligands correlated with the natural degree of breast cancer cell sensitivity to gefitinib. While breast cancer cells intrinsically resistant to gefitinib (IC50 ≥15 μM) markedly up-regulated (up to 600 times) the expression of genes codifying for HERspecific ligands, a significant down-regulation (up to 106 times) of HER ligand gene transcription was found in breast cancer cells intrinsically sensitive to gefitinib (IC50 ≤1 μM). Second, loss of HER1 function differentially regulated the nuclear trafficking of HER-related ligands. While gefitinib treatment induced an active import and nuclear accumulation of the HER ligand NRG in intrinsically gefitinib-resistant breast cancer cells, an active export and nuclear loss of NRG was observed in intrinsically gefitinib-sensitive breast cancer cells. In summary, through in vitro and pharmacodynamic studies we have learned that, besides mutations in the HER1 gene, oncogenic changes downstream of HER1 are the key players regulating gefitinib efficacy in breast cancer cells. It now appears that pharmacological inhibition of HER1 function also leads to striking changes in both the gene expression and the nucleo-cytoplasmic trafficking of HER-specific ligands, and that this response correlates with the intrinsic degree of breast cancer sensitivity to the EGFR TKI gefitinib. The relevance of this previously unrecognized intracrine feedback to gefitinib warrants further studies as cancer cells could bypass the antiproliferative effects of HER1-targeted therapeutics without a need for the overexpression and/or activation of other HER family members and/or the activation of HER-driven downstream signaling cascades

Development and psychometric properties of the Resistance to Trauma Test (TRauma)

Resumen tomado de la publicaci??n

Inherited resistance to arsenate toxicity in two populations of Lumbricus rubellus

No unequivocal evidence exists of genetically inherited resistance to metals/metalloids in field populations of earthworms. We studied cocoon production in adult Lumbricus rubellus Hoffmeister collected from an abandoned arsenic and copper mine (Devon Great Consols, Devon, UK), and abandoned tungsten mine (Carrock Fell, Cumbria, UK) and an uncontaminated cultured population. The earthworms were kept in uncontaminated soil for nine weeks. From a total of 42 L. rubellus from each site, Devon Great Consols adults produced 301 cocoons, of which 42 were viable; Carrock Fell 60 cocoons, of which 11 were viable; and the reference population 101 cocoons, of which 62 were viable. The hatchlings were collected and stored at 4degreesC at weekly intervals. After 12 weeks, all hatchlings were transferred to clean soil and maintained at 15degreesC for 20 weeks until they showed evidence of a clitellum. In toxicity trials, F1 generation L. rubellus were exposed to 2,000 mg As/kg as sodium arsenate or 300 mg Cu/kg as copper chloride for 28 d. The F1 generation L. rubellus from Devon Great Consols mine demonstrated resistance to arsenate but not copper. All L. rubellus from Devon Great Consols kept in soil treated with sodium arsenate remained in good condition over the 28-d period but lost condition rapidly and suffered high mortality in soil treated with copper chloride. The control population suffered high mortality in soil treated with sodium arsenate and copper chloride. Previous work has shown that field-collected adults demonstrate resistance to both arsenate and Cu toxicity under these conditions. Thus, while arsenate resistance may be demonstrated in F1 generation L. rubellus from one of the contaminated sites, Cu resistance is not. The F1 adults and F2 cocoons did not have significantly higher levels of As than the control population, with no residual As tissue burden, suggesting that resistance to As in these populations may be inherited.

Statistical methods for examining genetic influences of resistance to anti-epileptic drugs

It is generally accepted that genetics may be an important factor in explaining the variation between patients’ responses to certain drugs. However, identification and confirmation of the responsible genetic variants is proving to be a challenge in many cases. A number of difficulties that maybe encountered in pursuit of these variants, such as non-replication of a true effect, population structure and selection bias, can be mitigated or at least reduced by appropriate statistical methodology. Another major statistical challenge facing pharmacogenetics studies is trying to detect possibly small polygenic effects using large volumes of genetic data, while controlling the number of false positive signals. Here we review statistical design and analysis options available for investigations of genetic resistance to anti-epileptic drugs.

Genotypic differences in the growth of bananas (Musa spp.) infected with migratory endoparasitic nematodes. 1. Roots

The effects of nematodes on root morphology and the association of root characteristics with resistance to nematodes of seven banana varieties were investigated in two experiments. Banana plants were grown in controlled conditions within polytunnels and harvested on three occasions for the measurement of root morpholopy, and biomass. Varieties differed in their resistance to nematodes, from resistant (Yg Km5, FHIA 17, FHIA 03) and partly resistant (FHIA 01, FHIA 25) to not resistant ((FHIA 23, Williams). Nematodes reduced the root dry weight of FHIA 01, FHIA 17 and FHIA 23 at some harvests. Primary root number was on average 9.5% lower in nematode-infected plants than controls, with no differences among the varieties. Thus, there was no simple association between the resistance of these varieties and their tolerance to nematodes. Varieties differed in root morphology. Root dry weight was greatest for resistant varieties Yg Km5 and FHIA 03, and least for non-resistant varieties FHIA 23 and Williams. Thus, resistance to nematodes was associated with varieties with greater root mass and more and larger primary roots.

Genotypic differences in the growth of bananas (Musa spp.) infected with migratory endoparasitic nematodes. 2. Shoots

In order to identify the effect of burrowing nematodes on the shoots (pseudostem and leaves) of banana plants and to determine whether or not shoot characteristics are associated with plant resistance to nematodes two experiments were conducted in controlled conditions within polytunnels. The banana plants were harvested on three occasions for the measurement of root morphology and biomass. Varieties differed in their resistance to nematodes from resistant (Yg Km5, FHIA 17, FHIA 03) and partly resistant (FHIA 01, FHIA 25) to not resistant (FHIA 23, Williams). Nematodes reduced total plant dry weight at the first harvest in Experiment 1 and by an average of 8.8% in Experiment 2, but did not affect leaf area in either experiment. The ratio of above-ground Weight to total plant weight was reduced from 75% to 72% in nematode-infected plants compared with the control plants for all varieties tested in Experiment 1, but was only reduced in FHIA 25 and FHIA 23 in Experiment 2. Varieties differed in above-ground growth. The FHIA varieties had greater shoot weights and leaf area than YgKm5 and Williams. Overall, resistance to nematodes was associated with the partitioning of a greater proportion of biomass to the roots than to above-ground parts.

The staphylococcus aureus surface protein IsdA mediates resistance to the innate defenses of human skin

Resistance to human skin innate defenses is crucial for survival and carriage of Staphylococcus aureus, a common cutaneous pathogen and nasal colonizer. Free fatty acids extracted from human skin sebum possess potent antimicrobial activity against S. aureus. The mechanisms by which S. aureus overcomes this host defense during colonization remain unknown. Here, we show that S. aureus IsdA, a surface protein produced in response to the host, decreases bacterial cellular hydrophobicity rendering them resistant to bactericidal human skin fatty acids and peptides. IsdA is required for survival of S. aureus on live human skin. Reciprocally, skin fatty acids prevent the production of virulence determinants and the induction of antibiotic resistance in S. aureus and other Gram-positive pathogens. A purified human skin fatty acid was effective in treating systemic and topical infections of S. aureus suggesting that our natural defense mechanisms can be exploited to combat drug-resistant pathogens.

An evaluation of the costs of making specific secondary metabolites: does the yield penalty incurred by host plant resistance to insects due to competition for resources?

The presumption that the synthesis of 'defence' compounds in plants must incur some 'trade-off' or penalty in terms of annual crop yields has been used to explain observed inverse correlations between resistance to herbivores and rates of growth or photosynthesis. An analysis of the cost of making secondary compounds suggests that this accounts for only a small part of the overall carbon budget of annual crop plants. Even the highest reported amounts of secondary metabolites found in different crop species (flavonoids, allylisothiocyanates, hydroxamic acids, 2-tridecanone) represent a carbon demand that can be satisfied by less than an hour's photosynthesis. Similar considerations apply to secondary compounds containing nitrogen or sulphur, which are unlikely to represent a major investment compared to the cost of making proteins, the major demand for these elements. Decreases in growth and photosynthesis in response to stress are more likely the result of programmed down-regulation. Observed correlations between yield and low contents of unpalatable or toxic compounds may be the result of parallel selection during the refinement of crop species by humans.