In MMTV-Her-2/neu transgenic mammary tumors the absence of caveolin-1−/− alters PTEN and NHERF1 but not β-catenin expression

In a recent study, we have shown that in mammary tumors from mice lacking the Cav-1 gene, there are alterations in specific heat shock proteins as well as in tumor development. With this in mind, we have now investigated other proteins in the same mammary mouse tumor model (Her-2/neu expressing mammary tumors from Cav-1 wild type and Cav-1 null mice), to further comprehend the complex tumor-stroma mechanisms involved in regulating stress responses during tumor development. In this tumor model the cancer cells always lacked of Cav-1, so the KO influenced the Cav-1 in the stroma. By immunohistochemistry, we have found a striking co-expression of β-catenin and Her-2/neu in the tumor cells. The absence of Cav-1 in the tumor stroma had no effect on expression or localization of β-catenin and Her-2/neu. Both proteins appeared co-localized at the cell surface during tumor development and progression. Since Her-2/neu activation induces MTA1, we next evaluated MTA1 in the mouse tumors. Although this protein was found in numerous nuclei, the absence of Cav-1 did not alter its expression level. In contrast, significantly more PTEN protein was noted in the tumors lacking Cav-1 in the stroma, with the protein localized mainly in the nuclei. P-Akt levels were relatively low in tumors from both Cav-1 WT and Cav-1 KO mice. There was also an increase in nuclear NHERF1 expression levels in the tumors arising from Cav-1 KO mice. The data obtained in the MMTV-neu model are consistent with a role for Cav-1 in adjacent breast cancer stromal cells in modulating the expression and localization of important proteins implicated in tumor cell behavior.     

Wildlife value orientations as predicting factors in support of reintroducing bison and of wolves migrating to Germany

In the light of the worldwide biodiversity convention, the return of the wolf and the planned reintroduction of the European bison to Germany are seen as success stories in efforts to protect biological diversity. Prerequisite to the successful long-term reintroduction of wild animals is the support and approval of the return of animal populations by the general public. To better understand opinions towards wildlife and wildlife management, which often underlie controversies, the influence of wildlife related value orientations has been the focus of empirical research in recent years. In the current study, we examined wildlife value orientations in a sample of German students (n = 364) majoring in three different university subjects: agriculture; landscape ecology/nature conservation; and, social sciences. Analysis showed internal consistencies among the items comprising the wildlife value orientation scale. As theoretically expected, results of multiple regression analysis revealed wildlife value orientations have great impact on a decision to support the return of wolves and bison to Germany. In conclusion, the instrument, developed in the US, turned out to be reliable and had predictive value for the use in Germany. Also, we found differences in wildlife value orientation in relation to the factors of gender and academic background. A value orientation that focuses on mutualism was usually subjected to gender and academic major interaction effects. Males and females within and between student groups placed different weight on wildlife value orientations, possibly generating a potential for conflicts relating to wildlife management decisions, such as the reintroduction of bison or the support of wolves’ return.     

Prognostic implication of HSPA (HSP70) in breast cancer patients treated with neoadjuvant anthracycline-based chemotherapy

Neoadjuvant chemotherapy is used in patients with locally advanced breast cancer to reduce tumor size before surgery. Unfortunately, resistance to chemotherapy may arise from a variety of mechanisms. Heat shock proteins (HSPs), which are highly expressed in mammary tumor cells, have been implicated in anticancer drug resistance. In spite of the widely described value of HSPs as molecular markers in cancer, their implications in breast tumors treated with anthracycline-based neoadjuvant chemotherapy has been poorly explored. In this study, we have evaluated, by immunohistochemistry, the expression of HSP27 (HSPB1) and HSP70 (HSPA) in serial biopsies from locally advanced breast cancer patients (n = 60) treated with doxorubicin (DOX)- or epirubicin (EPI)-based monochemotherapy. Serial biopsies were taken at days 1, 3, 7, and 21, and compared with prechemotherapy and surgical biopsies. After surgery, the patients received additional chemotherapy with cyclophosphamide, methotrexate, and 5-fluorouracil. High nuclear HSPB1 and HSPA expressions were found in invasive cells after DOX/EPI administration (P < 0.001), but the drug did not affect the cytoplasmic expression of the HSPs. Infiltrating lymphocytes showed high nuclear HSPA (P < 0.01) levels at postchemotherapy. No correlations were found between HSPs expression and the clinical and pathological response to neoadjuvant therapy. However, in postchemotherapy biopsies, high nuclear (>31 % of the cells) and cytoplasmic HSPA expressions (>11 % of the tumor cells) were associated with better DFS (P = 0.0348 and P = 0.0118, respectively). We conclude that HSPA expression may be a useful prognostic marker in breast cancer patients treated with neoadjuvant DOX/EPI chemotherapy indicating the need to change the administered drugs after surgery for overcoming drug resistance.     

Reconstitution of the recombinant human γ-tubulin ring complex

Cryo-electron microscopy recently resolved the structure of the vertebrate γ-tubulin ring complex (γ-TuRC) purified from Xenopus laevis egg extract and human cells to near-atomic resolution. These studies clarified the arrangement and stoichiometry of γ-TuRC components and revealed that one molecule of actin and the small protein MZT1 are embedded into the complex. Based on this structural census of γ-TuRC core components, we developed a recombinant expression system for the reconstitution and purification of human γ-TuRC from insect cells. The recombinant γ-TuRC recapitulates the structure of purified native γ-TuRC and has similar functional properties in terms of microtubule nucleation and minus end capping. This recombinant system is a central step towards deciphering the activation mechanisms of the γ-TuRC and the function of individual γ-TuRC core components.     

Antimicrobial peptides: biochemical determinants of activity and biophysical techniques of elucidating their functionality

Antimicrobial peptides (AMPs) have been established over millennia as powerful components of the innate immune system of many organisms. Due to their broad spectrum of activity and the development of host resistance against them being unlikely, AMPs are strong candidates for controlling drug-resistant pathogenic microbial pathogens. AMPs cause cell death through several independent or cooperative mechanisms involving membrane lysis, non-lytic activity, and/or intracellular mechanisms. Biochemical determinants such as peptide length, primary sequence, charge, secondary structure, hydrophobicity, amphipathicity and host cell membrane composition together influence the biological activities of peptides. A number of biophysical techniques have been used in recent years to study the mechanisms of action of AMPs. This work appraises the molecular parameters that determine the biocidal activity of AMPs and overviews their mechanisms of actions and the diverse biochemical, biophysical and microscopy techniques utilised to elucidate these.