MicroRNA-224 is implicated in lung cancer pathogenesis through targeting caspase-3 and caspase-7

We recently reported that miR-224 was significantly up-regulated in non-small cell lung cancer (NSCLC) tissues, in particular in resected NSCLC metastasis. We further demonstrated that miR-224 functions as an oncogene in NSCLC by directly targeting TNFAIP1 and SMAD4. However, the biological functions of miR-224 in NSCLC are controversial and underlying mechanisms of miR-224 in the progression and metastasis of lung cancer remain to be further explored. Here we report that caspase3 (CASP3) and caspase7 (CASP7) are previously unidentified targets of miR-224 in NSCLC, and that miR-224 promotes lung cancer cells proliferation and migration in part by directly targeting CASP7 and down-regulating its expression. In addition, miR-224 attenuated TNF-α induced apoptosis by direct targeting of CASP3 resulting in reduction of cleaved PARP1 expression in lung cancer cells. Furthermore, the expression of miR-224 negatively correlates with the expression of CASP7 and CASP3 in tissue samples from patients with lung cancer. Finally, we found that activated NF-κB signaling is involved in the regulation of miR-224 expression in lung cancer. Our study provides new insight in understanding of oncogenic role of miR-224 in the lung cancer pathogenesis and suggests that NF-κB/miR-224/CASP3, 7 pathway could be a putative therapeutic target in lung cancer.

Abstract LB-289: Interaction between miR-155 and Quaking in the innate immune response and leukemia

Rationale: miR-155 is a pro-inflammatory microRNA upregulated in human and mouse macrophages exposed to lipopolysaccharide (LPS) that is required to mount an effective immune response. High levels of miR-155 are observed in different solid tumors as well as leukemias, including chronic lymphocytic leukemia (CLL). Quaking (QKI) is a tumor-suppressor gene encoding a conserved RNA-binding protein. In silico analyses predict that the QKI transcript is a target of miR-155, and we hypothesized that miR-155 might carry out its pro-inflammatory and oncogenic signals at least in part by targeting QKI. Methods: Mouse RAW-264.7 macrophages were stimulated with LPS or mock PBS three times over a period of 6 days. qRT-PCR was used to monitor the expression of QKI, miR-155 and Tnf (tumor necrosis factor alpha), and Quaking protein (Qki) expression was analyzed by Western blot. Expression of miR-155 and QKI in Burkitt's lymphoma cell lines and CLL cell lines was measured by qRT-PCR; QKI expression was also determined by Western blot. Cell lines were transfected with miR-155 or miR-control, or 155-I, and Western blot analysis of QKI was performed after 48 hours. To study the in vivo effects of the cooperation between miR-155 and QKI, we analyzed Qki expression in splenic B cells from wild type C57B1/6 mice, miR-155−/- mice, and Eμ-miR-155 transgenic mice (which develop aggressive CLL), with and without LPS challenge. Finally, expression of Qki was determined in samples from patients with B-cell CLL. Results: After 8 hours of LPS challenge there was a 2-fold decrease in QKI expression, while miR-155 and Tnf both increased approximately 10-fold (p<0.05). QKI returned to pre-treatment levels at 2 days, while miR-155remained high for 3 days. LPS re-stimulation at 3 days (mimicking chronic inflammation) reduced QKI expression 2.3-fold (p<0.05) over a 48 hour period in parallel with a renewed up-regulation of miR-155, and Western blotting confirmed the above observed changes for Qki. CLL-derived cell lines showed significantly higher expression of miR-155, and lower expression of QKI, compared with Burkitt's lymphoma cell lines (p<0.05). Transfection of miR-155 led to decreased Qki expression in Burkitt's lymphoma lines, while 155-I transfection of MEC2 CLL cells caused Qki upregulation at 48 hours. Splenic B cells from leukemic Eμ-miR-155 mice had decreased Qki levels compared with C57B1/6 mice and miR-155−/−mice, and LPS challenge of cultured B cells resulted in a pronounced downregulation of Qki expression only in B cells coming from Eμ-miR-155 mice. Finally, reduced expression of Qki was observed in B cells coming from patients with CLL compared with healthy patients. Conclusions: The inverse relationship between miR-155 and Qki is specific, and may represent a regulatory mechanism for the immune response mounted by macrophages and B cells. This relationship also sheds light on the pro-inflammatory and oncogenic properties of miR-155 in leukemia.

Citation Format: Timothy K. Richmond, Esmerina Tili, Melissa Brown, Marcela Chiabai, Dario Palmieri, Ri Cui, Tyler Sheetz, Carlo M. Croce. Interaction between miR-155 and Quaking in the innate immune response and leukemia. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-289. doi:10.1158/1538-7445.AM2015-LB-289

Regulated Expression of miR-155 is Required for iNKT Cell Development

Invariant natural killer T cells (iNKT cells) are CD1d-restricted, lipid antigen-reactive T lymphocytes with immunoregulatory functions. iNKT cell development in the thymus proceeds through subsequent stages, defined by the expression of CD44 and NK1.1, and is dictated by a unique gene expression program, including microRNAs. Here, we investigated whether miR-155, a microRNA involved in differentiation of most hematopoietic cells, played any role in iNKT cell development. To this end, we assessed the expression of miR-155 along iNKT cell maturation in the thymus, and studied the effects of miR-155 on iNKT cell development using Lck-miR-155 transgenic mice, which over express miR-155 in T cell lineage under the lymphocyte-specific protein tyrosine kinase (Lck) promoter. We show that miR-155 is expressed by newly selected immature wild-type iNKT cells and turned off along iNKT cells differentiation. In transgenic mice, miR-155 over-expression resulted in a substantial block of iNKT cell maturation at Stage 2, in the thymus toward an overall reduction of peripheral iNKT cells, unlike mainstream T cells. Furthermore, the effects of miR-155 over-expression on iNKT cell differentiation were cell autonomous. Finally, we identified Ets1 and ITK transcripts as relevant targets of miR-155 in iNKT cell differentiation. Altogether, these results demonstrate that a tight control of miR-155 expression is required for the development of iNKT cells.

Role of MYC-regulated long noncoding RNAs in cell cycle regulation and tumorigenesis

BACKGROUND

The functions of long noncoding RNAs (lncRNAs) have been identified in several cancers, but the roles of lncRNAs in colorectal cancer (CRC) are less well understood. The transcription factor MYC is known to regulate lncRNAs and has been implicated in cancer cell proliferation and tumorigenesis.

METHODS

CRC cells and tissues were profiled to identify lncRNAs differentially expressed in CRC, from which we further selected MYC-regulated lncRNAs. We used luciferase promoter assay, ChIP, RNA pull-down assay, deletion mapping assay, LC-MS/MS and RNA immunoprecipitation to determine the mechanisms of MYC regulation of lncRNAs. Moreover, soft agar assay and in vivo xenograft experiments (four athymic nude mice per group) provided evidence of MYC-regulated lncRNAs in cancer cell transformation and tumorigenesis. The Kaplan-Meier method was used for survival analyses. All statistical tests were two-sided.

RESULTS

We identified lncRNAs differentially expressed in CRC (P < .05, greater than two-fold) and verified four lncRNAs upregulated and two downregulated in CRC cells and tissues. We further identified MYC-regulated lncRNAs, named MYCLos. The MYC-regulated MYCLos may function in cell proliferation and cell cycle by regulating MYC target genes such as CDKN1A (p21) and CDKN2B (p15), suggesting new regulatory mechanisms of MYC-repressed target genes through lncRNAs. RNA binding proteins including HuR and hnRNPK are involved in the function of MYCLos by interacting with MYCLo-1 and MYCLo-2, respectively. Knockdown experiments also showed that MYCLo-2, differentially expressed not only in CRC but also in prostate cancer, has a role in cancer transformation and tumorigenesis.

CONCLUSIONS

Our results provide novel regulatory mechanisms in MYC function through lncRNAs and new potential lncRNA targets of CRC.

Control of MicroRNA expression as a new way for resveratrol to deliver its beneficial effects

Grapes produce large amounts of polyphenols. Many of them accumulate in the skin, pulp, and seeds and are consequently found in wine. The health benefits of a moderate consumption of wine have been attributed at least in part to grape's polyphenols. Among them, resveratrol (3,5,4'-trihydroxystilbene) is a phytoalexin that stimulates plant cell defenses against infections and also plays protective roles in humans, where it delays cardiovascular alterations and exerts anticancer and anti-inflammatory effects. Despite numerous studies, the molecular mechanisms of resveratrol action are only partially understood. Given its pleiotropic effects, it was previously suggested that resveratrol protective properties may arise from its modulation of the expression of microRNAs. Therefore, this review will focus on the effects of resveratrol on microRNA populations in humans and human cell lines, especially emphasizing the microRNAs that have been implicated in resveratrol effects on inflammation, cancer, metabolism, and muscle differentiation.

Identification of new binding partners of the chemosensory signaling protein Gγ13 expressed in taste and olfactory sensory cells

Tastant detection in the oral cavity involves selective receptors localized at the apical extremity of a subset of specialized taste bud cells called taste receptor cells (TRCs). The identification of the genes coding for the taste receptors involved in this process have greatly improved our understanding of the molecular mechanisms underlying detection. However, how these receptors signal in TRCs, and whether the components of the signaling cascades interact with each other or are organized in complexes is mostly unexplored. Here we report on the identification of three new binding partners for the mouse G protein gamma 13 subunit (Gγ13), a component of the bitter taste receptors signaling cascade. For two of these Gγ13 associated proteins, namely GOPC and MPDZ, we describe the expression in taste bud cells for the first time. Furthermore, we demonstrate by means of a yeast two-hybrid interaction assay that the C terminal PDZ binding motif of Gγ13 interacts with selected PDZ domains in these proteins. In the case of the PDZ domain-containing protein zona occludens-1 (ZO-1), a major component of the tight junction defining the boundary between the apical and baso-lateral region of TRCs, we identified the first PDZ domain as the site of strong interaction with Gγ13. This association was further confirmed by co-immunoprecipitation experiments in HEK 293 cells. In addition, we present immunohistological data supporting partial co-localization of GOPC, MPDZ, or ZO-1, and Gγ13 in taste buds cells. Finally, we extend this observation to olfactory sensory neurons (OSNs), another type of chemosensory cells known to express both ZO-1 and Gγ13. Taken together our results implicate these new interaction partners in the sub-cellular distribution of Gγ13 in olfactory and gustatory primary sensory cells.

Resveratrol, MicroRNAs, Inflammation, and Cancer

MicroRNAs are short noncoding RNAs that regulate the expression of many target genes posttranscriptionally and are thus implicated in a wide array of cellular and developmental processes. The expression of miR-155 or miR-21 is upregulated during the course of the inflammatory response, but these microRNAs are also considered oncogenes due to their upregulation of expression in several types of tumors. Furthermore, it is now well established that inflammation is associated with the induction or the aggravation of nearly 25% of cancers. Therefore, the above microRNAs are thought to link inflammation and cancer. Recently, resveratrol (trans-3,4′,5-trihydroxystilbene), a natural polyphenol with antioxidant, anti-inflammatory, and anticancer properties, currently at the stage of preclinical studies for human cancer prevention, has been shown to induce the expression of miR-663, a tumor-suppressor and anti-inflammatory microRNA, while downregulating miR-155 and miR-21. In this paper we will discuss how the use of resveratrol in therapeutics may benefit from the preanalyses on the status of expression of miR-155 or miR-21 as well as of TGFβ1. In addition, we will discuss how resveratrol activity might possibly be enhanced by simultaneously manipulating the levels of its key target microRNAs, such as miR-663.

GAM/ZFp/ZNF512B is central to a gene sensor circuitry involving cell-cycle regulators, TGF{beta} effectors, Drosha and microRNAs with opposite oncogenic potentials

MicroRNAs (miRNAs) are small regulatory RNAs targeting multiple effectors of cell homeostasis and development, whose malfunctions are associated with major pathologies such as cancer. Herein we show that GAM/ZFp/ZNF512B works within an intricate gene regulatory network involving cell-cycle regulators, TGFβ effectors and oncogenic miRNAs of the miR-17-92 cluster. Thus, GAM impairs the transcriptional activation of the miR-17-92 promoter by c-Myc, downregulates miR-17-92 miRNAs differentially, and limits the activation of genes responsive to TGFβ canonical pathway. In contrast, TGFβ decreases GAM transcripts levels while differentially upregulating miR-17-92 miRNAs. In turn, miR-17, miR-20a and miR-92a-1 target GAM transcripts, thus establishing a feedback autoregulatory loop. GAM transcripts are also targeted by miRNAs of the let-7 family. GAM downregulates Drosha, the main effector of miRNA maturation in the nucleus, and interacts with it in a RNA-dependent manner. Finally, GAM modulates the levels of E2F1 and Ras, and increases apoptosis while reducing cell proliferation. We propose that GAM represents a new kind of vertebrate regulator aimed at balancing the opposite effects of regulators of cell homeostasis by increasing the robustness of gene circuitries controlling cell proliferation, differentiation and development.

Resveratrol decreases the levels of miR-155 by upregulating miR-663, a microRNA targeting JunB and JunD

An inflammatory component is present in the microenvironment of most neoplastic tissues, including those not causally related to an obvious inflammatory process. Several microRNAs, and especially miR-155, play an essential role in both the innate and adaptative immune response. Resveratrol (trans-3,4',5-trihydroxystilbene) is a natural antioxidant with anti-inflammatory properties that is currently at the stage of preclinical studies for human cancer prevention. Here, we establish that, in human THP-1 monocytic cells as well as in human blood monocytes, resveratrol upregulates miR-663, a microRNA potentially targeting multiple genes implicated in the immune response. In THP-1 cells, miR-663 decreases endogenous activator protein-1 (AP-1) activity and impairs its upregulation by lipopolysaccharides (LPS), at least in part by directly targeting JunB and JunD transcripts. We further establish that the downregulation of AP-1 activity by resveratrol is miR-663 dependent and that the effects of resveratrol on both AP-1 activity and JunB levels are dose dependent. Finally, we show that resveratrol impairs the upregulation of miR-155 by LPS in a miR-663-dependent manner. Given the role of miR-155 in the innate immune response and the fact that it is upregulated in many cancers, our results suggest that manipulating miR-663 levels may help to optimize the use of resveratrol as both an anti-inflammatory and anticancer agent against malignancies associated with high levels of miR-155.

Resveratrol decreases the levels of miR-155 by upregulating miR-663, a microRNA targeting JunB and JunD

An inflammatory component is present in the microenvironment of most neoplastic tissues, including those not causally related to an obvious inflammatory process. Several microRNAs, and especially miR-155, play an essential role in both the innate and adaptative immune response. Resveratrol (trans-3,4',5-trihydroxystilbene) is a natural antioxidant with anti-inflammatory properties that is currently at the stage of preclinical studies for human cancer prevention. Here, we establish that, in human THP-1 monocytic cells as well as in human blood monocytes, resveratrol upregulates miR-663, a microRNA potentially targeting multiple genes implicated in the immune response. In THP-1 cells, miR-663 decreases endogenous activator protein-1 (AP-1) activity and impairs its upregulation by lipopolysaccharides (LPS), at least in part by directly targeting JunB and JunD transcripts. We further establish that the downregulation of AP-1 activity by resveratrol is miR-663 dependent and that the effects of resveratrol on both AP-1 activity and JunB levels are dose dependent. Finally, we show that resveratrol impairs the upregulation of miR-155 by LPS in a miR-663-dependent manner. Given the role of miR-155 in the innate immune response and the fact that it is upregulated in many cancers, our results suggest that manipulating miR-663 levels may help to optimize the use of resveratrol as both an anti-inflammatory and anticancer agent against malignancies associated with high levels of miR-155.

miR-155: on the crosstalk between inflammation and cancer

MicroRNAs are short non-coding RNAs that posttranscriptionally modulate the expression of multiple target genes and are thus implicated in a wide array of cellular and developmental processes. miR-155 is processed from BIC, a non-coding transcript highly expressed in both activated B and T cells and in monocytes/macrophages. miR-155 levels change dynamically during both hematopoietic lineage differentiation and the course of the immune response. Different mouse models developed recently indicate that miR-155 plays a critical role during hematopoiesis and regulates lymphocyte homeostasis and tolerance. A moderate increase of miR-155 levels is observed in many types of malignancies of B cell or myeloid origin, and transgenic over-expression of miR-155 in mice results in cancer. While the high levels of miR-155 reached transiently during the course of the immune response remain unharmful for the organism, the reason why a moderate up-regulation of miR-155 can lead to cancer remains obscure. As prolonged exposure to inflammation can lead to cancer, the permanent up-regulation of miR-155 might be a link between the two. Therefore, designing miR-155 based therapies will require a better understanding of the molecular basis of its action as well as of how miR-155 levels are regulated in a cell-specific manner.

MicroRNAs, the immune system and rheumatic disease

MicroRNAs (miRNAs) are short noncoding RNA molecules that modulate the expression of multiple target genes at the post-transcriptional level and are implicated in a wide array of cellular and developmental processes. In hematopoietic cells, miRNA levels are dynamically regulated during lineage differentiation and also during the course of the immune response. Mouse models have provided good evidence for miRNAs being key players in the establishment of hematopoietic lineages. Furthermore, miRNA-dependent alterations in gene expression in hematopoietic cells are critical for mounting an appropriate immune response to a wide range of pathogens, spontaneously emerging tumors, and autoimmune cells. Deregulation of hematopoietic-specific miRNA expression results in defects in both central and peripheral tolerance, hematopoietic malignancies, and sometimes both. Abnormal expression of miRNAs-which is implicated in inflammation-has also been found in patients with rheumatoid arthritis. These findings identify miRNAs as critical targets for immunomodulatory drug development.

Effects of fluoroquinolones on bacterial adhesion and on preformed biofilm of strains isolated from urinary double J stents

The activity of levofloxacin and ulifloxacin on biofilm formation and persistence was evaluated on microorganisms isolated from urinary double-J-stents. We analyzed 51 bacterial strains and their susceptibility to different antimicrobial classes was determined. We evaluated the bacterial ability to form biofilm and the effects of different concentrations of levofloxacin and ulifloxacin on bacterial adhesion and biofilm persistence. Most of the strains were biofilm producers with no relevant difference in biofilm production at 24 or 48 hours. The fluoroquinolones were able to prevent biofilm formation, but not to eradicate the preformed biofilm. On the basis of our data we advise that antibiotic prophylaxis with fluoroquinolones may be most helpful if given at the time of stent insertion and at high dosage.

Expression and function of micro-RNAs in immune cells during normal or disease state

Micro-RNAs (miRNAs) are 19-24 nucleotide long non-coding RNAs that posttranscriptionally modulate gene expression. They are found in almost all species: viruses, plants, nematodes, fly, fish, mouse, human, and are implicated in a wide array of cellular and developmental processes. Microarray-based miRNA profiling brought to the discovery of miRNAs specific to different hematopoietic lineages. Furthermore, the functional assays performed in tissue cultures to discover miRNAs involved in immune responses in combination with the reports of miRNA-transgenic or miRNA -knockout mouse models has helped elucidating the miRNA roles in the development and function of immune system. Abnormal patterns of hematopoietic-specific miRNAs have been found in different types of cancer and miRNA based gene therapy is being considered as a potential technology of choice in immunological disorders and cancer. The purpose of this review is to discuss recent findings related with the expression and function of miRNAs in hematopoietic lineages.

miRNAs and their potential for use against cancer and other diseases

miRNAs are 19-24 nucleotide long noncoding RNAs found in almost all genetically dissected species, including viruses, plants, nematodes, flies, fish, mice and humans. Rapid advances have been made in understanding their physiological functions, while abnormal patterns of miRNA expression have been found in many disease states, most notably human cancer. It is now clear that miRNAs represent a class of genes with a great potential for use in diagnosis, prognosis and therapy. In this review we will focus on the discoveries that elucidate their crucial role in mammalian diseases, particularly in cancer, and propose that miRNA-based gene therapy might become the potential technology of choice in a wide range of human diseases including cancer.

Modulation of miR-155 and miR-125b levels following lipopolysaccharide/TNF-alpha stimulation and their possible roles in regulating the response to endotoxin shock

We report here that miR-155 and miR-125b play a role in innate immune response. LPS stimulation of mouse Raw 264.7 macrophages resulted in the up-regulation of miR-155 and down-regulation of miR-125b levels. The same changes also occurred when C57BL/6 mice were i.p. injected with LPS. Furthermore, the levels of miR-155 and miR-125b in Raw 264.7 cells displayed oscillatory changes in response to TNF-alpha. These changes were impaired by pretreating the cells with the proteasome inhibitor MG-132, suggesting that these two microRNAs (miRNAs) may be at least transiently under the direct control of NF-kappaB transcriptional activity. We show that miR-155 most probably directly targets transcript coding for several proteins involved in LPS signaling such as the Fas-associated death domain protein (FADD), IkappaB kinase epsilon (IKKepsilon), and the receptor (TNFR superfamily)-interacting serine-threonine kinase 1 (Ripk1) while enhancing TNF-alpha translation. In contrast, miR-125b targets the 3'-untranslated region of TNF-alpha transcripts; therefore, its down-regulation in response to LPS may be required for proper TNF-alpha production. Finally, Emu-miR-155 transgenic mice produced higher levels of TNF-alpha when exposed to LPS and were hypersensitive to LPS/d-galactosamine-induced septic shock. Altogether, our data suggest that the LPS/TNF-alpha-dependent regulation of miR-155 and miR-125b may be implicated in the response to endotoxin shock, thus offering new targets for drug design.

Ultraconserved regions encoding ncRNAs are altered in human leukemias and carcinomas

Noncoding RNA (ncRNA) transcripts are thought to be involved in human tumorigenesis. We report that a large fraction of genomic ultraconserved regions (UCRs) encode a particular set of ncRNAs whose expression is altered in human cancers. Genome-wide profiling revealed that UCRs have distinct signatures in human leukemias and carcinomas. UCRs are frequently located at fragile sites and genomic regions involved in cancers. We identified certain UCRs whose expression may be regulated by microRNAs abnormally expressed in human chronic lymphocytic leukemia, and we proved that the inhibition of an overexpressed UCR induces apoptosis in colon cancer cells. Our findings argue that ncRNAs and interaction between noncoding genes are involved in tumorigenesis to a greater extent than previously thought.

Pre-B cell proliferation and lymphoblastic leukemia/high-grade lymphoma in E(mu)-miR155 transgenic mice

MicroRNAs (miRNAs) represent a newly discovered class of posttranscriptional regulatory noncoding small RNAs that bind to targeted mRNAs and either block their translation or initiate their degradation. miRNA profiling of hematopoietic lineages in humans and mice showed that some miRNAs are differentially expressed during hematopoietic development, suggesting a role in hematopoietic cell differentiation. In addition, recent studies suggest the involvement of miRNAs in the initiation and progression of cancer. miR155 and BIC, its host gene, have been reported to accumulate in human B cell lymphomas, especially in diffuse large B cell lymphomas, Hodgkin lymphomas, and certain types of Burkitt lymphomas. Here, we show that E(mu)-mmu-miR155 transgenic mice exhibit initially a preleukemic pre-B cell proliferation evident in spleen and bone marrow, followed by frank B cell malignancy. These findings indicate that the role of miR155 is to induce polyclonal expansion, favoring the capture of secondary genetic changes for full transformation.

Cloning and characterization of cDNAs expressed during chick development and encoding different isoforms of a putative zinc finger transcriptional regulator

Development proceeds through successive activation of different sets of genes by specific transcription factors as a consequence of cell interactions and signaling. It is thus of primary interest to identify new putative transcriptional regulators. We report here the isolation of chicken clones bearing sequences coding for a chicken zinc finger protein (chZFp) which contains four pairs of zinc fingers of mixed type C2-H-C/C2-H2. At least five chZFp isoforms are produced through differential splicing of four small exons. The amino acid domains encoded by these four exons are highly conserved across species. Northern blot analysis and RNase-protection assays showed that chZFp transcripts are present in brain, heart, skin and liver during chick development. Reverse transcription mediated polymerase chain reaction (RT-PCR) experiments suggested that the relative amount of some chZFp isoforms increases at critical stages of development and skin morphogenesis. Finally, the main chZFp isoforms are able to directly interact in vitro with the scaffold attachment factor-A (SAF-A, also known as heterogenous nuclear ribonucleoprotein U) through both their aminoterminal and carboxyterminal domains.

Interpretive criteria for disk diffusion susceptibility testing of ulifloxacin, the active metabolite of prulifloxacin

Prulifloxacin, a new fluoroquinolone, is a prodrug whose active compound, ulifloxacin, is derived from its transformation after oral administration and intestinal absorption. Based on early pharmacokinetic and pharmacodynamic data, the following MIC breakpoints have tentatively been proposed: < or = 1 microg/ml, susceptible; 2 microg/ml, intermediate; and > or = 4 microg/ml, resistant. In this report, ulifloxacin MIC vs. zone diameter scattergrams and discrepancy rates were analyzed in 461 freshly isolated clinical strains (237 Enterobacteriaceae, 101 nonfermenters, and 123 Gram-positive bacteria). In agreement with the guidelines of the National Committee for Clinical Laboratory Standards, a modification of the error rate-bounded method was used to select disk diffusion test breakpoints. The following zone diameter breakpoints were chosen and are proposed herein for the interpretation of ulifloxacin disk (5 microg) test results: < or = 15 and > or = 19 mm for Enterobacteriaceae, < or = 16 and > or = 20 mm for nonfermenters, and < or = 14 and > or = 18 mm for Gram-positive bacteria. By applying these breakpoint values, no very major errors were detected, while major and minor errors were largely below the accepted discrepancy rates.

Expression of Bax in yeast affects not only the mitochondria but also vacuolar integrity and intracellular protein traffic

Bax-induced lethality in yeast is accompanied by morphological changes in mitochondria, giving rise to a reduced number of swollen tubules. Although these changes are completely abolished upon coexpression of the Bax inhibitor, Bcl-2, coexpression of Bax with Bax inhibiting-glutathione S-transferase (BI-GST) leads to aggregation, but not fusion of the mitochondria. In addition, Bax affects the integrity of yeast vacuoles, resulting in the disintegration and eventual loss of the organelles, and the disruption of intracellular protein traffic. While Bcl-2 coexpression only partially corrects this phenotype, coexpression of BI-GST fully restores the organelles, indicating a different mode of protection exerted by Bcl-2 and BI-GST.